Tuesday, 30 August 2016

CS Fallback Feature

If operators have a mature UTRAN or GERAN network before the initial deployment of the evolved packet system (EPS), the legacy circuit switched (CS) network can be reused to provide CS services and the EPS can be used to provide packet switched (PS) services. This helps operators protect their investments in legacy CS networks.
CSFB and VoIP over IMS are two standard solutions used to provide CS services for E-UTRAN UEs. In view of the technological maturity, industry chain, and deployment costs of these two solutions, CSFB can serve as an interim solution for CS service access before the commercial use of the IP multimedia subsystem (IMS).

2.1 Introduction

When a UE in an E-UTRAN network attempts to initiate a CS service, the CSFB feature enables the UE to fall back to the UTRAN or GERAN for CS service access.

2.2 Benefits

CSFB provides the following benefits:
  • Provides CS services in the E-UTRAN network without the need of additional devices.
  • Implements the short message service (SMS) and location service (LCS).
  • Helps operators reduce costs by reusing legacy CS networks without the need to deploy the IMS.

2.3 Architecture

To implement CSFB to UTRAN/GERAN, an SGs interface is required between the MME and MSC server. Figure 2-1 shows the network architecture for CSFB to UTRAN/GERAN.
Figure 2-1 Network architecture for CSFB to UTRAN/GERAN
NOTE:
E-UTRAN: evolved UMTS terrestrial radio access network
GERAN: GSM/EDGE radio access network
MME: mobility management entity
MSC: mobile switching center
SGSN: serving GPRS support node
UE: user equipment
UTRAN: universal terrestrial radio access network
Table 2-1 describes the elements of the network architecture for CSFB to UTRAN/GERAN.
Table 2-1 Elements of the network architecture for CSFB to UTRAN/GERAN
Element
Function
SGs interface
  • Acts as an interface between the MME and MSC server.
  • Assists mobility management and paging between the EPS and the CS network.
  • Transmits SMS messages.
  • Transmits messages related to combined attach and combined TAU/LAU.
UE
  • Is capable of accessing the EPS and accessing the UTRAN, GERAN, or both.
  • Supports combined EPS/IMSI attach, combined EPS/IMSI detach, and combined TAU/LAU.
  • Supports CSFB mechanisms, such as PS redirection and PS handover.
NOTE:
CSFB-capable UEs must support SMS over SGs, but UEs that support SMS over SGs are not necessarily CSFB-capable.
MME
  • Connects to the MSC over the SGs interface.
  • Selects the visitor location register (VLR) and location area identity (LAI) based on the tracking area identity (TAI) of the serving cell.
  • Forwards paging messages delivered by the MSC.
  • Performs public land mobile network (PLMN) selection and reselection.
  • Supports combined EPS/IMSI attach, combined EPS/IMSI detach, and combined TAU/LAU.
  • Routes CS signaling.
  • Supports SMS over SGs.
  • Supports RAN information management (RIM) if flash CSFB or cell change order (CCO) with network assisted cell change (NACC) is used as a CSFB mechanism.
MSC
  • Supports combined EPS/IMSI attach.
  • Supports SMS over SGs.
  • Forwards paging messages transmitted over the SGs interface.
E-UTRAN
  • Forwards paging messages related to CSFB.
  • Selects target cells for CSFB for UEs.
  • Supports one or more of the following functions:
    PS redirection to UTRAN or GERAN, if PS redirection is used as the CSFB mechanism
    PS handover to UTRAN or GERAN, if PS handover is used as the CSFB mechanism
    CCO without NACC to GERAN, if CCO without NACC is used as the CSFB mechanism
    RIM for acquiring the system information about GERAN cells, if NACC is used as the CSFB mechanism
    RIM for acquiring the system information about UTRAN or GERAN cells, in addition to PS redirection, if flash CSFB is used as the CSFB mechanism
UTRAN/GERAN
Supports one or more of the following functions:
  • Incoming handovers from the E-UTRAN, if PS handover is used as the CSFB mechanism
  • RIM for delivering the system information about GERAN cells to eNodeBs, if NACC is used as the CSFB mechanism
  • RIM for delivering the system information about UTRAN or GERAN cells to eNodeBs, in addition to PS redirection, if flash CSFB is used as the CSFB mechanism
NOTE:
The UTRAN and GERAN do not need to provide extra functions to support PS redirection. The GERAN does not need to provide extra functions to support CCO without NACC.
SGSN
Does not activate Idle Mode Signaling Reduction (ISR) during the combined RAU/LAU procedure initiated by the UE. RAU is short for routing area update.
Supports RIM if flash CSFB or CCO with NACC is used as a CSFB mechanism.
NOTE:
ISR is a mechanism for reducing the inter-RAT cell reselection signaling of a UE in idle mode. RAT is short for radio access technology. For details about ISR, see 3GPP TS 23.401 V9.2.0 Annex J.

3 End-to-End Procedures for CSFB

This chapter describes the functions that a Huawei eNodeB performs during end-to-end procedures for CSFB, including the following:
  • Combined EPS/IMSI attach
  • Preregistration
  • CSFB procedure for mobile-originated calls
  • CSFB procedure for mobile-terminated calls
  • CSFB procedure for SMS
  • CSFB procedure for emergency calls
  • CSFB procedure for LCS
Regarding the capabilities of UEs and networks, Huawei provides the following mechanisms for eNodeBs to perform CSFB to the UTRAN or GERAN for mobile-originated calls and mobile-terminated calls:
  • PS redirection
  • PS handover
  • CCO with or without NACC (CCO/NACC)

3.1 CSFB to UTRAN

After a UE is powered on in the E-UTRAN, it initiates a combined EPS/IMSI attach procedure. Then, the MME performs a UE location update over the SGs interface to allow the UMTS core network to learn about the UE location. When the UE enters another tracking area (TA) or returns to the E-UTRAN by cell reselection, the UE initiates a combined TAU/LAU procedure. The combined EPS/IMSI attach and combined TAU/LAU procedures are transparent to the E-UTRAN, and therefore the E-UTRAN cannot detect them. When a mobile-originated or mobile-terminated CS service is initiated, the E-UTRAN works with other network elements to perform CSFB.

3.1.1 Combined EPS/IMSI Attach Procedure

The combined EPS/IMSI attach procedure is transparent to the eNodeBs. After a CSFB-capable UE is powered on in the E-UTRAN, the UE initiates a combined EPS/IMSI attach procedure, as shown in Figure 3-1.
Figure 3-1 Combined EPS/IMSI attach procedure
NOTE:
The symbols that appear in signaling procedure figures throughout this document are explained as follows:
  • An arrow denotes the transmission of a message.
  • A plain box denotes a mandatory procedure.
  • A dashed box denotes an optional procedure.
The combined EPS/IMSI attach procedure is described as follows:
  1. The UE sends an Attach Request message to the MME, requesting a combined EPS/IMSI attach procedure. This message also indicates whether the CSFB or SMS over SGs function is required.
  2. The EPS attach procedure is performed the same way as it is performed within the LTE system. For details, see section 5.3.2 in 3GPP TS 23.401 V9.2.0.
  3. The MME allocates an LAI to the UE, and then it derives the VLR number for the UE based on the LAI. If multiple PLMNs are available for the CS domain, the MME selects a PLMN based on the information about the selected PLMN reported by the eNodeB.
  4. The MME sends the MSC/VLR a Location Update Request message, which contains the new LAI, IMSI, MME name, and location update type.
  5. The MSC/VLR stores the MME name and creates an SGs association with the MME.
  6. The MSC/VLR performs the location update procedure in the CS domain.
  7. The MSC/VLR responds to the MME with a Location Update Accept message that contains the temporary mobile subscriber identity (TMSI) allocated by the VLR. The location update procedure is successful.
  8. The UE is informed that the combined EPS/IMSI attach procedure is successful. If the network supports SMS over SGs but not CSFB, the message transmitted to the UE contains the information element (IE) SMS-only. The message indicates that the combined EPS/IMSI attach procedure is successful but only SMS services are supported.

3.1.2 CSFB Procedures for Mobile-Originated Calls and Mobile-Terminated Calls

Based on the capabilities of UEs and networks, the following mechanisms are available for an eNodeB to perform CSFB to UTRAN:
  • CSFB based on PS handover
  • CSFB based on PS redirection
  • Flash CSFB
Table 3-1 lists the advantages and disadvantages of the preceding mechanisms. These mechanisms are based on the measurement or blind (non-measurement) mode, and they are compared here based on the same mode.
Table 3-1 Comparison of fallback mechanisms for CSFB to UTRAN
Fallback Mechanism
Impact on Networks
Impact on UEs
CS Service Access Delay
PS Service Interruption Time
CSFB based on PS handover
Complex
Complex
Short
Short
CSFB based on PS redirection
Simple
Simple
Long
Long
Flash CSFB
Medium
Medium
Short
Medium

CSFB Based on PS Handover

During CSFB based on PS handover, the UE is transferred from the E-UTRAN to the UTRAN by performing a PS handover. It then initiates a CS service in the UTRAN.
CSFB Procedure for Mobile-Originated Calls
This section describes the procedure for CSFB to UTRAN based on PS handover for mobile-originated calls, as shown in Figure 3-2.
Figure 3-2 CSFB to UTRAN based on PS handover for mobile-originated calls
The procedure is described as follows:
  1. The UE sends an Extended Service Request message to the MME to initiate a CS service.
  2. The MME sends an S1-AP Request message to instruct the eNodeB to initiate a CSFB procedure. If the MME supports the LAI-related feature, it also delivers the LAI to the eNodeB.
  3. The eNodeB determines whether to perform a blind handover based on the UE capability, parameter settings, and algorithm policy. For details, see 4.1.1.1 Selecting Between a Blind Handover and a Measurement-based Handover.
  4. The eNodeB initiates a PS handover preparation. If the preparation is successful, the eNodeB instructs the UE to perform a handover.
    NOTE:
    The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see 4 CSFB at the eNodeB.
  5. After the handover, the UE may initiate a CS call establishment procedure with an LAU or combined RAU/LAU procedure in the UTRAN.
  6. The follow-up procedures are performed for the PS handover. These procedures include data forwarding, path switching, and RAU. This step is performed together with step 5.
NOTE:
For details about the PS handover procedure, see Mobility Management in Connected Mode Feature Parameter Description and section 5.5.2 in 3GPP TS 23.401 V9.2.0.
CSFB Procedure for Mobile-Terminated Calls
Figure 3-3 shows the procedure for CSFB to UTRAN based on PS handover for mobile-terminated calls.
Figure 3-3 CSFB to UTRAN based on PS handover for mobile-terminated calls
The procedure is described as follows:
  1. The MSC sends a Paging Request message from the CS domain to the MME over the SGs interface. Then, either of the following occurs:
    • If the UE is in idle mode, the MME sends a Paging message to the eNodeB. Then the eNodeB sends a Paging message over the Uu interface to inform the UE of an incoming call from the CS domain.
    • If the UE is in active mode, the MME sends an NAS message to the UE to inform it of an incoming call from the CS domain.
  2. Upon receiving the paging message from the CS domain, the UE sends an Extended Service Request message containing a CS Fallback Indicator to the MME.
  3. The MME instructs the eNodeB over the S1 interface to perform CSFB.
  4. The subsequent steps are similar to steps 3 through 6 in the procedure for CSFB to UTRAN based on PS handover for mobile-originated calls. The only difference is that the UE sends a Paging Response message from the UTRAN cell.

CSFB Based on PS Redirection

During CSFB based on PS redirection, the eNodeB receives a CS Fallback Indicator, and then it sends an RRC Connection Release message to release the UE. The message contains information about a target UTRAN frequency, reducing the time for the UE to search for a target network. After selecting the UTRAN, the UE acquires the system information of a UTRAN cell. Then, the UE performs initial access to the cell to initiate a CS service. For the UTRAN, the UE is initially connected to it.
CSFB Procedure for Mobile-Originated Calls
Figure 3-4 shows the procedure for CSFB to UTRAN based on PS redirection for mobile-originated calls.
Figure 3-4 CSFB to UTRAN based on PS redirection for mobile-originated calls
The procedure is described as follows:
  1. The UE sends an Extended Service Request message to the MME to initiate a CS service.
  2. The MME sends an S1-AP Request message to instruct the eNodeB to initiate a CSFB procedure. If the MME supports the LAI-related feature, it also delivers the LAI to the eNodeB.
  3. The eNodeB determines whether to perform a blind handover based on the UE capability, parameter settings, and algorithm policy. For details, see 4.1.1.1 Selecting Between a Blind Handover and a Measurement-based Handover.
  4. The eNodeB sends an RRC Connection Release message to instruct the UE to perform a redirection. The message contains information about a target UTRAN frequency. Then, the eNodeB initiates an S1 UE context release procedure.
    NOTE:
    The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see 4 CSFB at the eNodeB.
  5. The UE may initiate an LAU, a combined RAU/LAU, or both an RAU and an LAU in the target cell.
  6. The UE initiates a CS call establishment procedure in the target UTRAN cell.
CSFB Procedure for Mobile-Terminated Calls
In a mobile-terminated call, the MSC sends a Paging Request message from the CS domain to the MME over the SGs interface. Then, the MME or the eNodeB initiates a paging procedure for the UE, as shown in Figure 3-3. The subsequent steps are the same as the steps in the procedure for CSFB to UTRAN based on PS redirection for mobile-originated calls.

Flash CSFB

During the flash CSFB procedure, the eNodeB receives a CS Fallback Indicator, and then it sends an RRC Connection Release message to release the UE. The message contains information about a target UTRAN frequency, as well as one or more physical cell identities and their associated system information. In this way, the UE can quickly access the target UTRAN without the need to perform the procedure for acquiring system information of the target UTRAN cell. Then, the UE can directly initiate a CS service in the UTRAN cell.
NOTE:
Because flash CSFB complies with 3GPP Release 9, the networks and UEs involved must support 3GPP Release 9 or later.
CSFB Procedure for Mobile-Originated Calls
Figure 3-5 shows the procedure for flash CSFB to UTRAN for mobile-originated calls.
Figure 3-5 Flash CSFB to UTRAN for mobile-originated calls
The procedure is described as follows:
  1. The UE sends an Extended Service Request message to the MME to initiate a CS service.
  2. The MME sends an S1-AP Request message to instruct the eNodeB to initiate a CSFB procedure. If the MME supports the LAI-related feature, it also delivers the LAI to the eNodeB.
  3. The eNodeB determines whether to perform a blind handover based on the UE capability, parameter settings, and algorithm policy. For details, see 4.1.1.1 Selecting Between a Blind Handover and a Measurement-based Handover.
  4. The eNodeB sends an RRC Connection Release message to instruct the UE to perform a redirection. The message contains information about a target UTRAN frequency, as well as one or more physical cell identities and their associated system information. Then, the eNodeB initiates an S1 UE context release procedure.
    NOTE:
    The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see 4 CSFB at the eNodeB. The system information of the target cell is acquired during the RIM procedure. For details, see 3.1.6 RIM Procedure.
  5. The UE may initiate an LAU, a combined RAU/LAU, or both an RAU and an LAU in the target cell.
  6. The UE initiates a CS call establishment procedure in the target UTRAN cell.
CSFB Procedure for Mobile-Terminated Calls
In a mobile-terminated call, the MSC sends a Paging Request message from the CS domain to the MME over the SGs interface. Then, the MME or the eNodeB initiates a paging procedure for the UE, as shown in Figure 3-3. The subsequent steps are the same as the steps in the procedure for flash CSFB to UTRAN for mobile-originated calls.

3.1.3 CSFB Procedure for SMS

SMS services are unknown to the eNodeB because SMS messages are encapsulated in NAS messages. During interworking with the UTRAN, SMS messages are exchanged between the MME and MSC over the SGs interface. Because a UE does not require fallback to the UTRAN to perform an SMS service, the SMS over SGs function can be used in a place covered only by the E-UTRAN.
As the SMS service is transparent to the eNodeB, the procedure is not described in this document. For details about the procedure, see section 8.2 in 3GPP TS 23.272 V10.0.0.

3.1.4 CSFB Procedure for Emergency Calls

The CSFB procedure for an emergency call is the same as the CSFB procedure for a normal mobile-originated voice service. The UE sends an RRC Connection Request message over the Uu interface or the MME sends an INITIAL CONTEXT SETUP REQUEST or UE CONTEXT MODIFICATION REQUEST message to inform the eNodeB of the service type. Emergency calls take precedence over other services in the eNodeB.
If PS handover is used for CSFB for emergency calls, the eNodeB does not restrict the cells in the handover restriction list when selecting the target cell. The eNodeB sends the RNC a handover request with the IE CSFB high priority in the IE Source to Target Transparent Container. This request informs the RNC that a CSFB procedure is required for an emergency call. Upon receiving the information, the RNC preferentially processes this call when using related algorithms such as admission control.
If PS redirection is used for CSFB for emergency calls, the RRC Connection Request message that the UE sends when accessing the UTRAN contains the indication of an emergency call. The UTRAN handles this emergency call the same way it handles a common CS emergency call.
For details about admission and preemption of emergency calls, see Emergency Call Feature Parameter Description.

3.1.5 CSFB Procedure for LCS

After a UE initiates an LCS request, the MME performs an attach or combined TAU/LAU procedure to inform the UE of the LCS capability of the EPS. If the EPS does not support LCS, the UE falls back to the UTRAN to initiate LCS under the control of the EPS. The CSFB procedure is the same as the procedure for CSFB to UTRAN for mobile-originated calls.
If the UTRAN initiates an LCS request towards a UE camping on an E-UTRAN cell, the MSC sends an LCS indication to the MME over the SGs interface. Then, the MME instructs the eNodeB to perform CSFB for the UE. The CSFB procedure is the same as the procedure for CSFB to UTRAN for mobile-terminated calls. The UE performs the LCS service after the fallback to the UTRAN.
For details about the CSFB procedure for LCS, see section 8.3 in 3GPP TS 23.272 V10.0.0 and LCS Feature Parameter Description.

3.1.6 RIM Procedure

The RIM procedure exchanges information between the E-UTRAN and GERAN/UTRAN through the core networks. The procedure involves the eNodeB, MME, SGSN, and RNC/base station controller (BSC). Among these NEs, the MME and SGSN transfer but do not resolve information. Figure 3-6 shows the RIM procedure.
Figure 3-6 RIM procedure
The RIM procedure supports the following two information exchange modes:
  • Single Report
    In Single Report mode, the source device sends a request, and then the target device responds with a single report.
  • Multiple Report
    In Multiple Report mode, the target device responds with a report after receiving a request from the source device, and it also sends a report to the source device each time the system information changes. For details, see section 8c in 3GPP TS 48.018 V10.0.0.
Huawei eNodeBs support the two information exchange modes, and they acquire the system information of UTRAN cells during the RIM procedure. The Multiple Report mode is enabled or disabled by setting the RimSwitch parameter, while the Single Report mode is not configurable. The RIM procedure varies depending on parameter settings.
If...
Then...
Remarks
The UTRAN_RIM_SWITCH option under the RimSwitch(LTE TDD eNodeB,LTE TDD BTS3205E) parameter is selected
After an external UTRAN cell is set up, the eNodeB sends a request for system information to the UTRAN cell. The request specifies Multiple Report mode. If the UTRAN cell supports Multiple Report mode, the cell sends the system information to the eNodeB after the cell receives the request or the system information changes.
Whether a RIM procedure in Multiple Report mode can be triggered is based on the settings of the RIM switch and external UTRAN cells. For example, the RIM procedure cannot be triggered if the RIM switch is turned on but no external UTRAN cell is configured. If an external UTRAN cell has been configured, a RIM procedure is triggered each time the RIM switch is turned on.
The flash CSFB to UTRAN switch is turned on but the UTRAN_RIM_SWITCH option under the RimSwitch(LTE TDD eNodeB,LTE TDD BTS3205E) parameter is cleared
The eNodeB obtains the system information of each candidate UTRAN cell by performing the RIM procedure in Single Report mode.
The RIM procedure in Single Report mode is triggered during CSFB and increases the CSFB latency. Therefore, the RIM procedure in Multiple Report mode is recommended.

3.2 CSFB to GERAN

After a UE is powered on in the E-UTRAN, it initiates a combined EPS/IMSI attach procedure. Then, the MME performs a UE location update over the SGs interface to allow the GSM core network to learn about the UE location. When the UE enters another tracking area (TA) or returns to the E-UTRAN by cell reselection, the UE initiates a combined TAU/LAU procedure. The combined EPS/IMSI attach and combined TAU/LAU procedures are transparent to the E-UTRAN, and therefore the E-UTRAN cannot detect them. When a mobile-originated or mobile-terminated CS service is initiated, the E-UTRAN works with other network elements to perform CSFB.

3.2.1 Combined EPS/IMSI Attach Procedure

The combined EPS/IMSI attach procedure for CSFB to GERAN is the same as that for CSFB to UTRAN. For details, see 3.1.1 Combined EPS/IMSI Attach Procedure.

3.2.2 CSFB Procedures for Mobile-Originated Calls and Mobile-Terminated Calls

Based on the capabilities of UEs and networks, the following mechanisms are available for an eNodeB to perform CSFB to GERAN:
  • CSFB based on PS redirection
  • CSFB based on PS handover
  • CSFB based on CCO/NACC
  • Flash CSFB
Table 3-2 lists the advantages and disadvantages of the preceding mechanisms.
Table 3-2 Comparison of fallback mechanisms for CSFB to GERAN
Fallback Mechanism
Impact on Networks
Impact on UEs
CS Service Access Delay
PS Service Interruption Time
CSFB based on PS redirection
Simple
Simple
Long
Long
CSFB based on PS handover
Complex
Complex
Short
Short
CSFB based on CCO/NACC
Medium
Medium
Medium
Medium
Flash CSFB
Medium
Medium
Short
Medium

CSFB Based on PS Redirection

During CSFB based on PS redirection, the eNodeB receives a CS Fallback Indicator, and then it sends an RRC Connection Release message to release the UE. The message contains information about a target GERAN frequency, reducing the time for the UE to search for a target network. After selecting the GERAN, the UE acquires the system information of a GERAN cell. Then, the UE performs initial access to the cell to initiate a CS service. For the GERAN, the UE is initially connected to it.
CSFB Procedure for Mobile-Originated Calls
Figure 3-7 shows the procedure for CSFB to GERAN based on PS redirection for mobile-originated calls.
Figure 3-7 CSFB to GERAN based on PS redirection for mobile-originated calls
The procedure is described as follows:
  1. The UE sends an Extended Service Request message to the MME to initiate a CS service.
  2. The MME sends an S1-AP Request message to instruct the eNodeB to initiate a CSFB procedure. If the MME supports the LAI-related feature, it also delivers the LAI to the eNodeB.
  3. The eNodeB determines whether to perform a blind handover based on the UE capability, parameter settings, and algorithm policy. For details, see 4.1.1.1 Selecting Between a Blind Handover and a Measurement-based Handover.
  4. The eNodeB sends an RRC Connection Release message to instruct the UE to perform a redirection. The message contains information about a target GERAN frequency. Then, the eNodeB initiates an S1 UE context release procedure.
    NOTE:
    The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see 4 CSFB at the eNodeB.
  5. The UE may initiate an LAU, a combined RAU/LAU, or both an RAU and an LAU in the target cell.
  6. For the GERAN, the PS services would be suspended if the GERAN or UE does not support Dual Transfer Mode (DTM).
  7. The UE initiates a CS call establishment procedure in the target GERAN cell.
CSFB Procedure for Mobile-Terminated Calls
In a mobile-terminated call, the MSC sends a Paging Request message from the CS domain to the MME over the SGs interface. Then, the MME or the eNodeB initiates a paging procedure for the UE, as shown in Figure 3-3. The subsequent steps are the same as the steps in the procedure for CSFB to GERAN based on PS redirection for mobile-originated calls.

CSFB Based on PS Handover

During CSFB based on PS handover, the UE is transferred from the E-UTRAN to the GERAN by performing a PS handover. The UE then initiates a CS service in the GERAN. If the GERAN or some GERAN-supporting UEs do not support DTM, the ongoing PS services must be suspended before the CS services can be established.
CSFB Procedure for Mobile-Originated Calls
This section describes the procedure for CSFB to GERAN based on PS handover for mobile-originated calls, as shown in Figure 3-8.
Figure 3-8 CSFB to GERAN based on PS handover for mobile-originated calls
The procedure is described as follows:
  1. The UE sends an Extended Service Request message to the MME to initiate a CS service.
  2. The MME instructs the eNodeB to perform CSFB. If the MME supports the LAI-related feature, it also delivers the LAI to the eNodeB.
  3. The eNodeB determines whether to perform a blind handover based on the UE capability, parameter settings, and algorithm policy. For details, see 4.1.1.1 Selecting Between a Blind Handover and a Measurement-based Handover.
  4. The eNodeB initiates a PS handover preparation. If the preparation is successful, the eNodeB instructs the UE to perform a handover.
    If DTM is not supported by the UE or GERAN, the ongoing PS services of the UE are suspended. Meanwhile, the SGSN updates the bearers towards the S-GW/P-GW.
    NOTE:
    The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see 4 CSFB at the eNodeB.
  5. After the handover, the UE may initiate a CS call establishment procedure with an LAU or combined RAU/LAU procedure in the GERAN.
  6. The follow-up procedures are performed for the PS handover. These procedures include data forwarding, path switching, and RAU. This step is performed together with step 5.
CSFB Procedure for Mobile-Terminated Calls
In a mobile-terminated call, the MSC sends a Paging Request message from the CS domain to the MME over the SGs interface. Then, the MME or the eNodeB initiates a paging procedure for the UE, as shown in Figure 3-3. The subsequent steps are the same as the steps in the procedure for CSFB to GERAN based on PS handover for mobile-originated calls.

CSFB Based on CCO/NACC

During CSFB based on CCO/NACC, the eNodeB receives a CS Fallback Indicator from the MME, and then it sends a MobilityFromEUTRACommand message to the UE over the Uu interface. The message contains information about the operating frequency, ID, and system information of a target GERAN cell. The UE searches for the target cell based on the information it received, and then it performs initial access to the cell to initiate a CS service. If the GERAN or UEs do not support DTM, the ongoing PS services must be suspended before the CS services can be established.
CSFB Procedure for Mobile-Originated Calls
This section describes the procedure for CSFB to GERAN based on CCO/NACC for mobile-originated calls, as shown in Figure 3-9.
Figure 3-9 CSFB to GERAN based on CCO/NACC for mobile-originated calls
The procedure is described as follows:
  1. The UE sends an Extended Service Request message to the MME to initiate a CS service.
  2. The MME sends an S1-AP Request message to instruct the eNodeB to initiate a CSFB procedure. If the MME supports the LAI-related feature, it also delivers the LAI to the eNodeB.
  3. The eNodeB determines whether to perform a blind handover based on the UE capability, parameter settings, and algorithm policy. For details, see 4.1.1.1 Selecting Between a Blind Handover and a Measurement-based Handover.
  4. The eNodeB sends a MobilityFromEUTRACommand message over the Uu interface to indicate the operating frequency and ID of the target GERAN cell. If the source cell has the system information of the target cell, the system information is also carried in the message.
    NOTE:
    The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see 4 CSFB at the eNodeB.
    The system information of the target cell is acquired during the RIM procedure. For details, see 3.1.6 RIM Procedure.
  5. The UE initiates an LAU, a combined RAU/LAU, or both an RAU and an LAU in the target cell.
  6. If DTM is not supported by the UE or GERAN, the ongoing PS services of the UE are suspended.
  7. The UE initiates a CS call establishment procedure in the target GERAN cell.
  8. The MME initiates an S1 UE context release procedure.
CSFB Procedure for Mobile-Terminated Calls
In a mobile-terminated call, the MSC sends a Paging Request message from the CS domain to the MME over the SGs interface. Then, the MME or the eNodeB initiates a paging procedure for the UE, as shown in Figure 3-3. The subsequent steps are the same as the steps in the procedure for CSFB to GERAN based on CCO/NACC for mobile-originated calls.

Flash CSFB

During the flash CSFB procedure, the eNodeB receives a CS Fallback Indicator, and then it sends an RRC Connection Release message to release the UE. The message contains information about a target GERAN carrier frequency group, as well as one or more physical cell identities and their associated system information. The UE searches for a target cell based on the information it received, and then it performs initial access to the cell to initiate a CS service. If the GERAN or some GERAN-supporting UEs do not support DTM, the ongoing PS services must be suspended before the CS services can be established.
NOTE:
Because flash CSFB complies with 3GPP Release 9, the networks and UEs involved must support 3GPP Release 9 or later.
CSFB Procedure for Mobile-Originated Calls
This section describes the procedure for flash CSFB to GERAN for mobile-originated calls, as shown in Figure 3-10.
Figure 3-10 Flash CSFB to GERAN for mobile-originated calls
The procedure is described as follows:
  1. The UE sends an Extended Service Request message to the MME to initiate a CS service.
  2. The MME sends an S1-AP Request message to instruct the eNodeB to initiate a CSFB procedure. If the MME supports the LAI-related feature, it also delivers the LAI to the eNodeB.
  3. The eNodeB determines whether to perform a blind handover based on the UE capability, parameter settings, and algorithm policy. For details, see 4.1.1.1 Selecting Between a Blind Handover and a Measurement-based Handover.
  4. The eNodeB sends an RRC Connection Release message to instruct the UE to perform a redirection. The message contains information about a target GERAN carrier frequency group, as well as one or more physical cell identities and their associated system information. Then, the eNodeB initiates an S1 UE context release procedure.
    NOTE:
    The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see 4 CSFB at the eNodeB.
    The system information of the target cell is acquired during the RIM procedure. For details, see 3.1.6 RIM Procedure.
  5. The UE initiates an LAU, a combined RAU/LAU, or both an RAU and an LAU in the target cell.
  6. If DTM is not supported by the UE or GERAN, the ongoing PS services of the UE are suspended.
  7. The UE initiates a CS call establishment procedure in the target GERAN cell.
CSFB Procedure for Mobile-Terminated Calls
In a mobile-terminated call, the MSC sends a Paging Request message from the CS domain to the MME over the SGs interface. Then, the MME or the eNodeB initiates a paging procedure for the UE, as shown in Figure 3-3. The subsequent steps are the same as the steps in the procedure for flash CSFB to GERAN for mobile-originated calls.

3.2.3 CSFB Procedure for SMS

SMS services are unknown to the eNodeB because SMS messages are encapsulated in NAS messages. During interworking with the GERAN, SMS messages are exchanged between the MME and MSC over the SGs interface. Because a UE does not require fallback to the GERAN to perform an SMS service, the SMS over SGs function can be used in a place covered only by the E-UTRAN.
As the SMS service is transparent to the eNodeB, the procedure is not described in this document. For details about the procedure, see section 8.2 in 3GPP TS 23.272 V10.0.0.

3.2.4 CSFB Procedure for Emergency Calls

The CSFB procedure for an emergency call is the same as the CSFB procedure for a normal mobile-originated voice service. The UE sends an RRC Connection Request message over the Uu interface or the MME sends an INITIAL CONTEXT SETUP REQUEST or UE CONTEXT MODIFICATION REQUEST message to inform the eNodeB of the service type. Emergency calls take precedence over other services in the eNodeB.
If PS handover is used for CSFB for emergency calls, the eNodeB does not restrict the cells in the handover restriction list when selecting the target cell.
If PS redirection is used for CSFB for emergency calls, the Channel Request message that the UE sends when accessing the GERAN contains the indication of an emergency call. The GERAN handles this emergency call the same way it handles a common CS emergency call.
For details about admission and preemption of emergency calls, see Emergency Call Feature Parameter Description.

3.2.5 CSFB Procedure for LCS

After a UE initiates an LCS request, the MME performs an attach or combined TAU/LAU procedure to inform the UE of the LCS capability of the EPS. If the EPS does not support LCS, the UE falls back to the GERAN to initiate LCS under the control of the EPS. The CSFB procedure is the same as the procedure for CSFB to GERAN for mobile-originated calls.
If the GERAN initiates an LCS request towards a UE camping on an E-UTRAN cell, the MSC sends an LCS indication to the MME over the SGs interface. Then, the MME instructs the eNodeB to perform CSFB for the UE. The CSFB procedure is the same as the procedure for CSFB to GERAN for mobile-terminated calls. The UE performs the LCS service after the fallback to the GERAN.
For details about the CSFB procedure for LCS, see section 8.3 in 3GPP TS 23.272 V10.0.0 and LCS Feature Parameter Description.

3.2.6 RIM procedure

The RIM procedure for CSFB to GERAN is similar to that for CSFB to UTRAN. For details, see 3.2.6 RIM procedure.
Huawei eNodeBs support the two information exchange modes, and they acquires the system information of GERAN cells during the RIM procedure. The Multiple Report mode is enabled or disabled by setting the RimSwitch parameter, while the Single Report mode is not configurable. The RIM procedure varies depending on parameter settings.
If...
Then...
Remarks
The GERAN_RIM_SWITCH option under the RimSwitch parameter is selected
After an external GERAN cell is set up, the eNodeB sends a request for system information to the GERAN cell. The request specifies Multiple Report mode. If the GERAN cell supports Multiple Report mode, the cell sends the system information to the eNodeB after the cell receives the request or the system information changes.
Whether a RIM procedure in Multiple Report mode can be triggered is based on the settings of the RIM switch and external GERAN cells. For example, the RIM procedure cannot be triggered if the RIM switch is turned on but no external GERAN cell is configured. If an external GERAN cell has been configured, a RIM procedure is triggered each time the RIM switch is turned on.
The flash CSFB to GERAN switch or CCO/NACC switch is turned on but the UTRAN_RIM_SWITCH option under the RimSwitch(LTE TDD eNodeB,LTE TDD BTS3205E) parameter is cleared
The eNodeB obtains the system information of each candidate GERAN cell by performing the RIM procedure in Single Report mode.
The RIM procedure in Single Report mode is triggered during CSFB and increases the CSFB latency. Therefore, the RIM procedure in Multiple Report mode is recommended.

4 CSFB at the eNodeB

This chapter describes the CSFB procedure performed by Huawei eNodeB and the settings for the parameters involved.

4.1 Overview

This section describes the algorithm principles and parameters for the following features:
  • TDLOFD-001033 CS Fallback to UTRAN
  • TDLOFD-001034 CS Fallback to GERAN
NOTE:
The enhanced CSFB features described in subsequent sections are based on the basic CSFB functions described in this section.
Figure 4-1 shows the CSFB procedure performed by the eNodeB.
Figure 4-1 CSFB procedure performed by the eNodeB
The CSFB procedure consists of the following phases:
  • Triggering phase
    After receiving a CS Fallback Indicator from the MME, the eNodeB decides whether to perform CSFB by means of a blind handover based on the UE capabilities and the setting of the blind handover switch. Compared with measurement-based handovers, blind handovers have shorter access delays but a lower handover success rate.
  • Measurement phase
    The eNodeB delivers the inter-RAT measurement configuration to the UE, and the UE performs inter-RAT measurements as instructed.
  • Decision phase
    The eNodeB evaluates the measurement results and generates a list of candidate cells.
  • Execution phase
    The eNodeB executes CSFB to enable the UE to initiate the CS service in the target cell.
    NOTE:
    Both measurement-based and blind handovers are applicable to CSFB based on PS handover, CCO, and PS redirection. The blind-handover switch for the three CSFB mechanisms is specified by the BlindHoSwitch option under the HoModeSwitch parameter.

4.1.1 Triggering Phase of CSFB

4.1.1.1 Selecting Between a Blind Handover and a Measurement-based Handover

After a UE initiates a CS service in an E-UTRAN cell, the MME sends the eNodeB an S1-AP Request message that contains a CS Fallback Indicator, notifying the eNodeB that the UE should be transferred to the target network. The target networks to which CSFB can be performed are specified by the HoAlgoSwitch parameter.
After receiving the CS Fallback Indicator, the eNodeB checks the blind-handover switch setting and UE capabilities for each RAT and performs accordingly:
  • If the BlindHoSwitch option under the HoModeSwitch parameter is cleared, blind handovers are prohibited. Under this condition, if the UE is capable of measuring a RAT, the eNodeB delivers the inter-RAT measurement configuration to the UE, instructing the UE to perform measurements on this RAT.
  • If the BlindHoSwitch option under the HoModeSwitch parameter is cleared and the UE is incapable of measuring a RAT, the eNodeB instructs the UE to perform CSFB based on blind redirection.
  • If the BlindHoSwitch option under the HoModeSwitch parameter is selected, blind handovers are allowed and the eNodeB instructs the UE to perform CSFB based on blind handover.
    NOTE:
    If flash CSFB is enabled and blind handovers are allowed, the principles for choosing between a blind handover and a measurement-based handover differ from the principles described in this section. For details, see 4.2 Flash CSFB.

4.1.1.2 Selecting Frequencies to Measure or a Target Cell

  • During a blind handover:
    The eNodeB selects a target cell for the blind handover. The handover takes both of the following priorities into consideration: the blind handover priority of the target RAT and that of the specific cell. The former takes precedence over the latter. If CSFB is triggered for an emergency call, an LCS-supportive RAT takes priority over a non-LCS-supportive RAT.
    • Selecting a high-priority RAT
      The priorities of RATs used in blind handovers for CSFB are specified by the InterRatHighestPri, InterRatSecondPri, and InterRatLowestPri parameters.
    • Selecting a high-priority cell for blind handovers
      The blind handover priority of an inter-RAT neighboring cell is specified by the BlindHoPriority parameter.
  • During a measurement-based handover:
    The eNodeB selects the frequency with the highest priority from the frequency priority list and sends the measurement configuration to the UE. If there are more than three frequencies with the highest priority, the eNodeB randomly selects three frequencies for measurement.
    NOTE:
    CSFB with LAI to UTRAN and E-UTRAN to UTRAN CS/PS Steering affect the handling procedures described in this chapter. For details, see 4.3 CSFB with LAI and 4.4 E-UTRAN to UTRAN CS/PS Steering.

4.1.2 Measurement Phase of CSFB

4.1.2.1 Measurement Configuration

The measurement configuration procedure and measurement gap configuration for CSFB to UTRAN/GERAN are the same as those for inter-RAT handovers. For details, see Mobility Management in Connected Mode Feature Parameter Description.

4.1.2.2 Measurement Reporting

CSFB is triggered by event B1, which is reported in event-triggered periodical reporting mode. The triggering of event B1 indicates that the signal quality of the neighboring cell is higher than a specified threshold. Section 5.5.4.7 in 3GPP TS 36.331 V10.0.0 defines the entering and leaving conditions of event B1 as follows:
  • Entering condition: Mn+Ofn-Hys > Thresh
  • Leaving condition: Mn+Ofn+Hys < Thresh
where
  • Mn is the measurement result of the neighboring cell.
  • Ofn is the frequency-specific offset for the frequency of the neighboring cell. It is contained in the associated measurement object IE in the measurement configuration.
  • Hys is the hysteresis for event B1. The hysteresis values for CSFB to UTRAN and GERAN are contained in the measurement configuration.
  • Thresh is the threshold for event B1. The values of Thresh are set based on the measurement quantities for each RAT, as follows:
    • The received signal code power (RSCP) threshold for CSFB to UTRAN is specified by CsfbHoUtranB1ThdRscp.
    • The Ec/No threshold for CSFB to UTRAN is specified by CsfbHoUtranB1ThdEcn0.
    • The received signal strength indicator (RSSI) threshold for CSFB to GERAN is specified by CsfbHoGeranB1Thd.
If the entering condition of event B1 is continuously met during a period known as time-to-trigger, the UE reports information about the cells that meet the condition to the eNodeB. The time-to-trigger for event B1 related to CSFB to UTRAN and GERAN is specified by the CsfbHoUtranTimeToTrig and CsfbHoGeranTimeToTrig parameters, respectively.
The following parameters related to event B1 for CSFB are the same as those related to event B1 for inter-RAT handovers:
  • Frequency-specific offset for the frequency of the neighboring cell
  • Hysteresis
  • Reporting interval
  • Maximum number of cells contained in one report
  • Number of periodic reports

4.1.3 Decision Phase of CSFB

In the decision phase of a measurement-based handover for CSFB, the eNodeB checks the measurement results reported by the UE. Based on the results, the eNodeB determines whether CSFB is to be initiated and, if so, determines the target cell for the CSFB.
After receiving the B1 event report, the eNodeB generates a list of candidate cells for CSFB. It selects the cell with the highest signal quality from this list as the target cell.
NOTE:
  • If CSFB with LAI is enabled, the decision phase of CSFB may be different. For details, see 4.3 CSFB with LAI.
  • If load-based CSFB is enabled, the principles for determining CSFB may be different. For details, see 4.6 Load-based CSFB.

4.1.4 Execution Phase of CSFB

Table 4-1 lists the mechanisms that are available for CSFB to UTRAN and GERAN. These mechanisms are arranged in descending order of priority. The applicable mechanisms are specified by the HoModeSwitch parameter. Huawei eNodeB selects a mechanism based on both the UE capability and priorities of mechanisms. For example, if the switch controlling PS handover from E-UTRAN to UTRAN is turned on but the UE does not support PS handover, the eNodeB checks whether the UE supports the mechanism with the second-highest priority. This process stops when the eNodeB selects a mechanism that the UE supports.
Table 4-1 CSFB mechanisms
Target Network
Mechanisms (in Descending Order of Priority)
UTRAN
  • PS handover
  • Flash CSFB
  • Redirection
GERAN
  • PS handover
  • CCO/NACC
  • Flash CSFB
  • Redirection

4.2 Flash CSFB

This section describes the algorithm principles and parameters related to flash CSFB, which involves the following optional features:
  • TDLOFD-001052 Flash CS Fallback to UTRAN
  • TDLOFD-001053 Flash CS Fallback to GERAN
Flash CSFB provides a fast CSFB mechanism. It shortens the end-to-end CSFB delay and improves user experience on CS services. Flash CSFB uses either of the following methods:
  • Blind handover. This reduces the inter-RAT measurement duration.
  • Redirection. The eNodeB sends the system information of the target cell to the UE. This reduces the time for the UE to obtain the system information of the target cell after the UE falls back.
Flash CSFB requires basic CSFB functions and also has enhanced blind handover and redirection functions.

Enhanced Blind Handover

If the BlindHoSwitch option under the HoModeSwitch parameter is selected and the UE supports RAT measurement, the following two scenarios apply:
  • If the CsfbAdaptiveBlindHoSwitch option under the HoAlgoSwitch parameter is selected, the eNodeB delivers the A1-related and inter-RAT measurement configuration to the UE. The A1 threshold is determined by the BlindHoA1ThdRsrp parameter. For details about inter-RAT measurement, see 4.1.2 Measurement Phase of CSFB. If the UE triggers this A1 event reporting, the eNodeB performs a blind handover for the UE. Otherwise, the eNodeB performs the measurement-based CSFB procedure.
  • If the CsfbAdaptiveBlindHoSwitch option under the HoAlgoSwitch parameter is cleared, the eNodeB performs a blind handover.

Enhanced Redirection

During a redirection procedure, an eNodeB can deliver the system information of a certain number of cells. The maximum number (indicated by N in this section) is specified by the CellInfoMaxUtranCellNum parameter for UTRAN cells or the CellInfoMaxGeranCellNum parameter for GERAN cells.
The eNodeB selects UTRAN or GERAN cells as follows:
  • During a blind handover:
    Among cells that operate on the target UTRAN frequency or GERAN carrier frequency group, the eNodeB queues candidate cells for the handover in the following sequence:
    • Cells that are assigned blind-handover priorities in descending order
    • Other cells
  • During a measurement-based handover:
    Among cells that operate on the target UTRAN frequency or GERAN carrier frequency group, the eNodeB queues candidate cells in the following sequence:
    • Neighboring cells indicated in the measurement report, in descending order of signal strength
    • Other cells
In either scenario, the eNodeB then filters out cells to which handovers are prohibited and cells whose system information has not been obtained. If the number of qualified cells in the queue exceeds N, the eNodeB selects the first N cells. If the number of qualified cells is equal to or less than N, the eNodeB selects all these cells.

4.3 CSFB with LAI

This section describes the algorithm principles and parameters related to CSFB with LAI, which involves the following optional features:
  • TDLOFD-001068 CS Fallback with LAI to UTRAN
  • TDLOFD-001069 CS Fallback with LAI to GERAN
NOTE:
CSFB with LAI is under license control, but not switch control.
In most cases, CSFB with LAI selects a target network among multiple PLMNs, and selects a proper LAC among multiple LACs. It provides the following benefits:
  • Supports multiple PLMNs and national roaming. The LAI is composed of the PLMN ID and LAC and the PLMN is the one with which the UE is registered. The UE needs to fall back to the CS domain in this PLMN when CSFB is performed. If the serving E-UTRAN cell has multiple neighboring UTRAN or GERAN cells with different PLMN IDs or the serving PLMN differs from the target PLMN, CSFB with LAI enables the UE to correctly fall back to the target PLMN.
  • Selects a neighboring cell with the same LAC as the registered one if there are multiple LAs in a TA. As a result, the LAU procedure is not required, which decreases the CSFB access delay.
The MME sends the INITIAL CONTEXT SETUP REQUEST or UE CONTEXT MODIFICATION REQUEST message containing the registered LAI to the eNodeB. After receiving the message, the eNodeB performs the following operations (in addition to those described in 4.1 Overview):
  • During a blind handover:
    The eNodeB checks all inter-RAT neighboring cells of the cell serving the UE and considers the following three sets of cells (in descending order of priority) based on the LAI:
    • Set 1: neighboring cells with the same PLMN ID and LAC as those indicated in the LAI received.
    • Set 2: neighboring cells with the same PLMN ID as, but different LACs from, those indicated in the LAI received.
    • Set 3: neighboring cells located in the serving PLMN of the UE. If the InterPlmnHoSwitch option under the HoAlgoSwitch parameter is selected, neighboring cells in other PLMNs in the PLMN list are also considered.
      The eNodeB selects the CSFB target cell from the set that has the highest priority among all sets whose criteria apply to at least one cell. If there are multiple neighboring cells in the highest-priority non-empty set, the eNodeB selects the neighboring cell with the highest blind-handover priority to be the CSFB target cell. If the three sets are all empty, the eNodeB delivers the inter-RAT measurement configuration to the UE, and CSFB will be performed in the form of a measurement-based handover.
  • During a measurement-based handover:
    The eNodeB delivers information about an inter-RAT frequency in the measurement configuration to the UE if all the following conditions are met:
    • The PLMN ID of any inter-RAT neighboring cell on this frequency is the same as the PLMN ID in the LAI received.
    • The UE supports this RAT.
    • The UE is capable of measuring this frequency.
    After receiving a measurement report from the UE, the eNodeB considers the candidate cells in sets 1 and 2. The eNodeB sorts cells in each candidate cell list by signal quality and selects a target cell from the lists in descending order of signal quality. For details about sets 1 and 2, see the previous description of a blind handover.
NOTE:
If the eNodeB cannot find a frequency or cell for measurement based on the LAI sent by the MME, the eNodeB performs the operations as described in 4.1.1.2 Selecting Frequencies to Measure or a Target Cell when no LAI is received.

4.4 E-UTRAN to UTRAN CS/PS Steering

This section describes the algorithm principles and parameters related to the TDLOFD-001078 E-UTRAN to UTRAN CS/PS Steering feature.
This feature provides a flexible method to select a target UTRAN frequency for CSFB. Based on the network plan and load balancing requirements, operators that have both the E-UTRAN and UTRAN can transfer UEs that are performing CS or PS services to specified UTRAN frequencies.

Basic Functions

The eNodeB selects a target UTRAN frequency for CSFB based on whether UEs are performing CS services and on the CS service priorities of UTRAN frequencies. In addition to the principles described in 4.1 Overview, the eNodeB adopts the following principles for a blind handover or a measurement-based handover:
  • During a blind handover:
    If E-UTRAN to UTRAN CS/PS steering is enabled and the UtranFreqLayerBlindSwitch option under the FreqLayerSwtich parameter is selected, the eNodeB first selects a RAT with the highest blind-handover priority. If the selected RAT is UTRAN,
    • The eNodeB places the frequencies in descending order based on the CS service priority. If there is more than one frequency with the highest priority, the eNodeB places the blind handover priority (BlindHoPriority) and frequency priority for UEs in RRC_CONNECTED mode (ConnFreqPriority) in descending order. Then the eNodeB selects a frequency or cell with the highest priority as the target frequency or cell.
    • If there are multiple frequencies or cells with the highest priority, the eNodeB randomly selects a frequency or cell.
  • During a measurement-based handover:
    If E-UTRAN to UTRAN CS/PS steering is activated and the UtranFreqLayerMeasSwitch option he FreqLayerSwtich parameter is selected,
    • The eNodeB places the frequencies in descending order based on the service priority and selects a frequency that has the highest priority as the measurement frequency.
    • If there are more than three frequencies with the highest priority, the eNodeB randomly selects three frequencies for measurement.
    NOTE:
    UtranFreqLayerMeasSwitch controls measurements on UTRAN frequencies but not on GERAN frequencies. In CSFB to GERAN scenarios, the eNodeB determines whether to instruct the UE to perform measurements based only on whether the UE supports the GERAN and GERAN frequencies.

Interaction with CSFB with LAI

If both CS fallback with LAI to UTRAN and E-UTRAN to UTRAN CS/PS steering are enabled simultaneously, the eNodeB performs the following operations:
  • During a blind handover:
    The eNodeB first selects the frequencies with the PLMN ID indicated in the received LAI. Among the cells on these frequencies, the eNodeB selects the cells on the frequencies with the highest CS service priority. Then, the eNodeB selects cells with the LAC indicated in the received LAI. If there are multiple qualified cells, the eNodeB queues the cells in the following sequence: (1) cells with blind-handover priorities (specified by the BlindHoPriority parameter) in descending order; (2) cells on frequencies with blind-redirection priorities for RRC_CONNECTED UEs (specified by the ConnFreqPriority parameter) in descending order. If there are still multiple frequencies/cells with the same priority, the eNodeB randomly selects a target frequency/cell for a blind handover.
  • During a measurement-based handover:
    The eNodeB selects the frequencies that meet all the following conditions:
    • The PLMN ID of any inter-RAT neighboring cell on a frequency is the same as the PLMN ID in the received LAI.
    • The UE supports this RAT.
    • The UE is capable of measuring the frequency.
    Then, in the measurement configuration to the UE, the eNodeB delivers information about inter-RAT frequencies with the highest CS service priority. If there are more than three frequencies with the highest priority, the eNodeB randomly selects three frequencies for measurement.

4.5 CSFB Flexible Steering

This section describes the algorithm principles and parameters related to CSFB flexible steering, which involves the following optional features:
  • TDLOFD-001088 CS Fallback Steering to UTRAN
  • TDLOFD-001089 CS Fallback Steering to GERAN
CSFB flexible steering provides a flexible method to select a target frequency for CSFB. Based on the network plan and load balancing requirements, operators that have both E-UTRAN and inter-RAT networks can transfer UEs to specified RATs and frequencies. Flexible steering can be performed based on the following factors:
  • UE status, including idle (supporting CS services only) and active (supporting CS and PS services)
  • Priorities of UTRAN frequencies in carrying CS services and CS+PS services. For example, R99 frequencies preferentially carry CS services, and High Speed Packet Access (HSPA) frequencies preferentially carry CS+PS services.
  • CSFB mechanisms, including handover-based CSFB, redirection-based CSFB, and CCO-based CSFB

Algorithm Principles

If the UtranCsfbSteeringSwitch or GeranCsfbSteeringSwitch option under the HoAlgoSwitch parameter is selected, the eNodeB verifies UE status after receiving a CS Fallback Indicator as follows:
  • If the CS Fallback Indicator is contained in an INITIAL CONTEXT SETUP REQUEST message, the eNodeB determines that this UE is in idle mode (supporting CS services only).
  • If the CS Fallback Indicator is contained in a UE CONTEXT MODIFICATION REQUEST message, the eNodeB determines that this UE is in connected mode (supporting CS+PS services).

Processing for UEs in Idle Mode

The eNodeB performs flexible steering for UEs in idle mode as follows:

Processing for UEs in Connected Mode

The eNodeB performs flexible steering for UEs in connected mode as follows:
NOTE:
The setting of the CsfbHoPolicyCfg parameter depends on UtranPsHoSwitch, GeranPsHoSwitch, GeranNaccSwitch, and GeranCcoSwitch under the HoModeSwitch parameter. For example, to enable handover-based CSFB to UTRAN, the CsfbHoPolicyCfg parameter must be set to PS_HO, and the UtranPsHoSwitch option must be selected. However, redirection-based CSFB is not affected by UtranRedirectSwitch or GeranRedirectSwitch.

4.6 Load-based CSFB

This section describes the algorithm principles and parameters related to load-based CSFB. No new license is required for load-based CSFB, which is an enhancement of TDLOFD-001033 CS Fallback to UTRAN.

Obtaining UTRAN Cell Load Information

Huawei eNodeBs obtain UTRAN cell load information through the RIM procedure. Obtaining UTRAN cell load information through RIM is under switch control, but not license control. The UtranLoadTransChan parameter specifies whether to enable this function.
An eNodeB determines whether to perform load-based CSFB to a UTRAN cell based on load status. In addition, the UTRAN cell load value is not required for the eNodeB because the eNodeB cannot determine the UTRAN cell load status based on the value.
In Single Report mode, the eNodeB can only obtain the UTRAN cell load value, such as the percentage of power load. However, in Multiple Report mode, the eNodeB can obtain the cell load value and the cell load status using the overload flag. Therefore, the RIM procedure is performed in Multiple Report mode. The RIM procedure is described as follows:
  1. If both the UtranCsfbSwitch and CSFBLoadInfoSwitch options under the HoAlgoSwitch parameter are selected, and UtranLoadTransChan is set to BASED_ON_RIM, the eNodeB sends the RAN-INFORMATION-REQUEST/Multiple Report message to the RNC to obtain the cell load value.
  2. After receiving the RIM request, the RNC includes the power load percentage in the cell load IE and the cell load state such as normal, congestion, and overload in the overload flag IE. Then, the RNC sends the RAN-INFORMATION/Multiple Report-Initial message to the eNodeB.
    NOTE:
    If the UTRAN cell load status is normal, the RNC does not carry the overload flag IE in the RAN-INFORMATION/Multiple Report message.
    Huawei RNCs extend the overload flag IE value specified in 3GPP specifications: from overload to overload and congestion.
  3. After sending the RAN-INFORMATION/Multiple Report-Initial message, if the UTRAN cell status changes among normal, congestion, and overload, the RNC actively informs the eNodeB of the cell load status by sending the RAN-INFORMATION/Multiple Report message.
After receiving the cell load information, the eNodeB saves it and uses it to select a target cell for CSFB to UTRAN.

Determining a Target UTRAN Cell

During load-based CSFB to UTRAN, the eNodeB selects a target UTRAN cell in the following order of priority:
  • Cell whose load status is normal
  • Congested cell
  • Overloaded cell
Other load-based CSFB procedures are the same as those for normal load sharing to UTRAN. For details, see MLB Feature Parameter Description.

4.7 CSFB Exception Handling

When a UE has initiated a call and the eNodeB performs measurement-based CSFB, the UE keeps staying in the EUTRAN due to the following exceptions:
  • The UE does not send the measurement report to the eNodeB.
  • After the eNodeB starts handover preparation, the MME does not respond to the eNodeB.
  • Handover preparation fails because the target RNC or BSC resource is congested.
To increase the CSFB success rate and improve user experience with CS services, Huawei provides CSFB exception handling, which is enabled by default without a license requirement.
When the eNodeB receives the CSFB indication, a timer starts. The timer length is specified by the CsfbProtectionTimer parameter. If the UE is still served by the eNodeB when the timer expires, the eNodeB performs the CSFB based on the blind redirection. Note that eNodeB preferentially performs blind redirection CSFB to a RAT that has not been measured. For example, if the UTRAN frequency has ever been measured, the eNodeB preferentially performs blind redirection CSFB to a GERAN cell.
If the blind-handover-based CSFB to the cell with the highest priority fails, the eNodeB performs a blind handover to a cell with the second-highest priority. If handover attempts fail for eight times, the eNodeB will perform CSFB based on blind redirection.

5 Related Features

5.1 Features Related to TDLOFD-001033 CS Fallback to UTRAN

Prerequisite Features

TDLOFD-001033 CS Fallback to UTRAN requires TDLOFD-001019 PS Inter-RAT Mobility between E-UTRAN and UTRAN.

Mutually Exclusive Features

When a UE initiates a CSFB request, the eNodeB cannot determine, according to 3GPP Release 9 specifications, whether the target inter-RAT network is a CDMA2000 1xRTT network or a GERAN/UTRAN. To prevent this problem, CSFB to GERAN/UTRAN cannot be used with CSFB to CDMA2000 1xRTT.
This feature does not work with the following features:
  • TDLOFD-001035 CS Fallback to CDMA2000 1xRTT
  • TDLOFD-001090 Enhanced CS Fallback to CDMA2000 1xRTT

Impacted Features

None

5.2 Features Related to TDLOFD-001034 CS Fallback to GERAN

Prerequisite Features

TDLOFD-001034 CS Fallback to GERAN requires TDLOFD-001020 PS Inter-RAT Mobility between E-UTRAN and GERAN.

Mutually Exclusive Features

When a UE initiates a CSFB request, the eNodeB cannot determine, according to 3GPP Release 9 specifications, whether the target inter-RAT network is a CDMA2000 1xRTT network or a GERAN/UTRAN. To prevent this problem, CSFB to GERAN/UTRAN cannot be used with CSFB to CDMA2000 1xRTT.
This feature does not work with the following features:
  • TDLOFD-001035 CS Fallback to CDMA2000 1xRTT
  • TDLOFD-001090 Enhanced CS Fallback to CDMA2000 1xRTT

Impacted Features

None

5.3 Features Related to TDLOFD-001052 Flash CS Fallback to UTRAN

Prerequisite Features

TDLOFD-001052 Flash CS Fallback to UTRAN requires TDLOFD-001033 CS Fallback to UTRAN.

Mutually Exclusive Features

When a UE initiates a CSFB request, the eNodeB cannot determine, according to 3GPP Release 9 specifications, whether the target inter-RAT network is a CDMA2000 1xRTT network or a GERAN/UTRAN. To prevent this problem, CSFB to GERAN/UTRAN cannot be used with CSFB to CDMA2000 1xRTT.
This feature does not work with the following features:
  • TDLOFD-001035 CS Fallback to CDMA2000 1xRTT
  • TDLOFD-001090 Enhanced CS Fallback to CDMA2000 1xRTT

Impacted Features

If the handover switch is turned on for TDLOFD-001019 PS Inter-RAT Mobility between E-UTRAN and UTRAN, and UEs support mobility from the E-UTRAN to the UTRAN, TDLOFD-001052 Flash CS Fallback to UTRAN does not take effect. That is, if handover to UTRAN is enabled and UEs are capable of such handovers, all inter-RAT procedures to the UTRAN including CSFB will preferentially be performed based on handovers.

5.4 Features Related to TDLOFD-001053 Flash CS Fallback to GERAN

Prerequisite Features

TDLOFD-001053 Flash CS Fallback to GERAN requires TDLOFD-001034 CS Fallback to GERAN.

Mutually Exclusive Features

When a UE initiates a CSFB request, the eNodeB cannot determine, according to 3GPP Release 9 specifications, whether the target inter-RAT network is a CDMA2000 1xRTT network or a GERAN/UTRAN. To prevent this problem, CSFB to GERAN/UTRAN cannot be used with CSFB to CDMA2000 1xRTT.
This feature does not work with the following features:
  • TDLOFD-001035 CS Fallback to CDMA2000 1xRTT
  • TDLOFD-001090 Enhanced CS Fallback to CDMA2000 1xRTT

Impacted Features

If the handover switch is turned on for TDLOFD-001020 PS Inter-RAT Mobility between E-UTRAN and GERAN, and UEs support mobility from the E-UTRAN to the GERAN, TDLOFD-001053 Flash CS Fallback to GERAN does not take effect. That is, if handover to GERAN is enabled and UEs are capable of such handovers, all inter-RAT procedures to the GERAN including CSFB will preferentially be performed based on handovers.

5.5 Features Related to TDLOFD-001068 CS Fallback with LAI to UTRAN

Prerequisite Features

TDLOFD-001068 CS Fallback with LAI to UTRAN requires TDLOFD-001033 CS Fallback to UTRAN.

Mutually Exclusive Features

When a UE initiates a CSFB request, the eNodeB cannot determine, according to 3GPP Release 9 specifications, whether the target inter-RAT network is a CDMA2000 1xRTT network or a GERAN/UTRAN. To prevent this problem, CSFB to GERAN/UTRAN cannot be used with CSFB to CDMA2000 1xRTT.
This feature does not work with the following features:
  • TDLOFD-001035 CS Fallback to CDMA2000 1xRTT
  • TDLOFD-001090 Enhanced CS Fallback to CDMA2000 1xRTT

Impacted Features

None

5.6 Features Related to TDLOFD-001069 CS Fallback with LAI to GERAN

Prerequisite Features

TDLOFD-001069 CS Fallback with LAI to GERAN requires TDLOFD-001034 CS Fallback to GERAN.

Mutually Exclusive Features

When a UE initiates a CSFB request, the eNodeB cannot determine, according to 3GPP Release 9 specifications, whether the target inter-RAT network is a CDMA2000 1xRTT network or a GERAN/UTRAN. To prevent this problem, CSFB to GERAN/UTRAN cannot be used with CSFB to CDMA2000 1xRTT.
This feature does not work with the following features:
  • TDLOFD-001035 CS Fallback to CDMA2000 1xRTT
  • TDLOFD-001090 Enhanced CS Fallback to CDMA2000 1xRTT

Impacted Features

None

5.7 Features Related to TDLOFD-001088 CS Fallback Steering to UTRAN

Prerequisite Features

TDLOFD-001088 CS Fallback Steering to UTRAN requires TDLOFD-001033 CS Fallback to UTRAN and TDLOFD-001078 E-UTRAN to UTRAN CS/PS Steering.

Mutually Exclusive Features

When a UE initiates a CSFB request, the eNodeB cannot determine, according to 3GPP Release 9 specifications, whether the target inter-RAT network is a CDMA2000 1xRTT network or a GERAN/UTRAN. To prevent this problem, CSFB to GERAN/UTRAN cannot be used with CSFB to CDMA2000 1xRTT.
This feature does not work with the following features:
  • TDLOFD-001035 CS Fallback to CDMA2000 1xRTT
  • TDLOFD-001090 Enhanced CS Fallback to CDMA2000 1xRTT

Impacted Features

This feature affects TDLOFD-001089 CS Fallback Steering to GERAN. In overlapping coverage of GSM, UMTS, and LTE networks, TDLOFD-001088 CS Fallback Steering to UTRAN and TDLOFD-001089 CS Fallback Steering to GERAN, if enabled simultaneously, achieve CSFB steering to different RATs.

5.8 Features Related to TDLOFD-001089 CS Fallback Steering to GERAN

Prerequisite Features

TDLOFD-001089 CS Fallback Steering to GERAN requires TDLOFD-001034 CS Fallback to GERAN.

Mutually Exclusive Features

When a UE initiates a CSFB request, the eNodeB cannot determine, according to 3GPP Release 9 specifications, whether the target inter-RAT network is a CDMA2000 1xRTT network or a GERAN/UTRAN. To prevent this problem, CSFB to GERAN/UTRAN cannot be used with CSFB to CDMA2000 1xRTT.
This feature does not work with the following features:
  • TDLOFD-001035 CS Fallback to CDMA2000 1xRTT
  • TDLOFD-001090 Enhanced CS Fallback to CDMA2000 1xRTT

Impacted Features

This feature affects TDLOFD-001088 CS Fallback Steering to UTRAN. In overlapping coverage of GSM, UMTS, and LTE networks, TDLOFD-001088 CS Fallback Steering to UTRAN and TDLOFD-001089 CS Fallback Steering to GERAN, if enabled simultaneously, achieve CSFB steering to different RATs.

5.9 Features Related to TDLOFD-001078 E-UTRAN to UTRAN CS/PS Steering

Prerequisite Features

This feature requires TDLOFD-001019 PS Inter-RAT Mobility between E-UTRAN and UTRAN and TDLOFD-001033 CS Fallback to UTRAN.

Mutually Exclusive Features

None

Impacted Features

None

6 Network Impact

6.1 TDLOFD-001033 CS Fallback to UTRAN

System Capacity

CSFB provides CS service access for E-UTRAN UEs. Considering that the number of UEs that request CS services within an area is relatively stable regardless of the deployment of the LTE networks, CSFB has no impact on the total number of UEs that request CS services within a network.
CSFB mechanisms affect signaling overhead as follows:
  • If redirection is used as the CSFB mechanism, no extra signaling message is required for the UTRAN because each CSFB procedure is equivalent to the initiation of a new CS service. The EPS does not need to interact with the target network, and the corresponding signaling overhead is negligible.
  • If PS handover is used as the CSFB mechanism, extra signaling messages are required from each NE for the request, preparation, and execution of each handover. However, from the perspective of traffic statistics, the number of UEs that initiate CS services per second per cell during peak hours is far below cell capacity. Therefore, signaling overhead caused by PS handovers is low.
  • Load-based CSFB to UTRAN prevents PS handover preparation failure caused by UTRAN cell congestion, because the eNodeB selects a target cell based on the UTRAN cell load status. This increases system capacity.

Network Performance

CSFB affects the access success rate as follows:
  • If redirection is used as the CSFB mechanism, each CSFB is equivalent to the initiation of a new CS service. Therefore, the access success rate for CSFB UEs is theoretically the same as that for normal CS UEs in the UTRAN.
  • If PS handover is used as the CSFB mechanism, the access success rate for CSFB UEs depends on the success rate of handovers to the target RAT. Handover-triggered CS service access has a higher requirement for signal quality compared with normal CS service access. Therefore, the access success rate for CSFB UEs is a little lower than that for normal UEs in the UTRAN.
  • Load-based CSFB to UTRAN prevents PS handover preparation failure caused by UTRAN cell congestion, because the eNodeB selects a target cell based on the UTRAN cell load status. This decreases the CSFB delay.

6.2 TDLOFD-001034 CS Fallback to GERAN

System Capacity

CSFB provides CS service access for E-UTRAN UEs. Considering that the number of UEs that request CS services within an area is relatively stable regardless of the deployment of the LTE networks, CSFB has no impact on the total number of UEs that request CS services within a network.
CSFB mechanisms affect signaling overhead as follows:
  • If redirection or CCO without NACC is used as the CSFB mechanism, no extra signaling message is required for the GERAN because each CSFB procedure is equivalent to the initiation of a new CS service. The EPS does not need to interact with the target network, and the corresponding signaling overhead is negligible.
  • If CCO with NACC is used as the CSFB mechanism, extra signaling messages are required only during eNodeB deployment. Afterward, signaling overhead is negligible because of infrequent system information updates.
  • If PS handover is used as the CSFB mechanism, extra signaling messages are required from each NE for the request, preparation, and execution of each handover. However, from the perspective of traffic statistics, the number of UEs that initiate CS services per second per cell during peak hours is far below cell capacity. Therefore, signaling overhead caused by PS handovers is low.

Network Performance

CSFB affects the access success rate as follows:
  • If PS redirection or CCO/NACC is used as the CSFB mechanism, each CSFB is equivalent to the initiation of a new CS service. Therefore, the access success rate for CSFB UEs is theoretically the same as that for normal CS UEs in the UTRAN.
  • If PS handover is used as the CSFB mechanism, the access success rate for CSFB UEs depends on the success rate of handovers to the target RAT. Handover-triggered CS service access has a higher requirement for signal quality compared with normal CS service access. Therefore, the access success rate for CSFB UEs is a little lower than that for normal UEs in the GERAN.

6.3 TDLOFD-001052 Flash CS Fallback to UTRAN

System Capacity

CSFB provides CS service access for E-UTRAN UEs. Considering that the number of UEs that request CS services within an area is relatively stable regardless of the deployment of the LTE networks, CSFB has no impact on the total number of UEs that request CS services within a network.
Flash CSFB affects signaling overhead as follows:
Extra signaling messages are required only during eNodeB deployment. Afterward, signaling overhead is negligible because of infrequent system information updates.

Network Performance

Flash CSFB affects the access success rate as follows:
  • Each flash CSFB procedure is equivalent to the initiation of a new CS service. Therefore, the access success rate for CSFB UEs is theoretically the same as that for normal CS UEs in the UTRAN.
  • Flash CSFB to UTRAN decreases the CSFB delay by up to 1.28s because UEs obtain information about the target UTRAN cell for redirection before RRC connections to the LTE network are released.
  • However, the RRC connection success rate may slightly decrease for the UTRAN. The uplink interference information contained in SIB7 in the UTRAN updates frequently. The RNC cannot update the uplink interference information in the system information sent to the LTE network based on SIB7 in the UTRAN. Therefore, the uplink interference information contained in SIB7 in the LTE network is a default value (-105 dBm). If the actual uplink interference in the UTRAN is greater than -105 dBm, the transmit power on UEs' physical random access channel (PRACH) increases and the RRC connection setup success rate may decrease.

6.4 TDLOFD-001053 Flash CS Fallback to GERAN

System Capacity

CSFB provides CS service access for E-UTRAN UEs. Considering that the number of UEs that request CS services within an area is relatively stable regardless of the deployment of the LTE networks, CSFB has no impact on the total number of UEs that request CS services within a network.
Flash CSFB affects signaling overhead as follows:
Extra signaling messages are required only during eNodeB deployment. Afterward, signaling overhead is negligible because of infrequent system information updates.

Network Performance

CSFB affects the access success rate as follows:
  • If flash CSFB is used as the CSFB mechanism, each CSFB is equivalent to the initiation of a new CS service. Therefore, the access success rate for CSFB UEs is theoretically the same as that for normal CS UEs in the GERAN.
  • Flash CSFB to GERAN decreases the CSFB delay by up to 2s because UEs obtain information about the target GERAN cell for redirection before RRC connections to the LTE network are released.

6.5 TDLOFD-001068 CS Fallback with LAI to UTRAN

System Capacity

No impact.

Network Performance

CSFB with LAI ensures that a UE can fall back to the CS network to which the UE has attached. This prevents CSFB failure or long delay caused by incorrect target RAT selection and increases the CSFB success rate.

6.6 TDLOFD-001069 CS Fallback with LAI to GERAN

System Capacity

No impact.

Network Performance

CSFB with LAI ensures that a UE can fall back to the CS network to which the UE has attached. This prevents CSFB failure or long delay caused by incorrect target RAT selection and increases the CSFB success rate.

6.7 TDLOFD-001088 CS Fallback Steering to UTRAN

System Capacity

No impact.

Network Performance

If the frequency with the highest priority is inappropriately configured, for example, if the highest-priority frequency has coverage holes, a UE may fail to measure this frequency and therefore the CSFB delay increases.

6.8 TDLOFD-001089 CS Fallback Steering to GERAN

System Capacity

No impact.

Network Performance

If the frequency with the highest priority is inappropriately configured, for example, if the highest-priority frequency has coverage holes, a UE may fail to measure this frequency and therefore the CSFB delay increases.

6.9 TDLOFD-001078 E-UTRAN to UTRAN CS/PS Steering

System Capacity

No impact.

Network Performance

No impact.

7 Engineering Guidelines

7.1 TDLOFD-001033 CS Fallback to UTRAN

7.1.1 When to Use CSFB to UTRAN

Use TDLOFD-001033 CS Fallback to UTRAN in the initial phase of LTE network deployment when both of the following conditions are met:
  • The operator owns a mature UTRAN network.
  • The E-UTRAN does not provide VoIP services, or UEs in the E-UTRAN do not support VoIP services.
For policies on whether to use PS handover or PS redirection for CSFB, see Mobility Management in Connected Mode Feature Parameter Description. If the UTRAN cell and E-UTRAN cell cover the same area, or the UTRAN cell provides better coverage than the E-UTRAN cell, use CSFB based on blind handover to decrease the CSFB delay.

7.1.2 Required Information

  1. Collect the operating frequencies, coverage areas, and configurations of the E-UTRAN and UTRAN cells.
  2. Collect the versions and configurations of the NEs in the E-UTRAN, UTRAN, and core networks, and ensure that they all support CSFB. Table 7-1 describes the requirements of CSFB to UTRAN for the core networks.
  3. Collect the following information about the UEs supporting UMTS and LTE on the live network:
    • Supported frequency bands
    • Whether the UEs support redirection from E-UTRAN to UTRAN
    • Whether the UEs support PS handover from E-UTRAN to UTRAN
    • Whether the UEs support UTRAN measurements
    This information is used to configure neighboring UTRAN cells and to determine whether to perform CSFB based on handover or redirection. For details, see Mobility Management in Connected Mode Feature Parameter Description.
  4. Obtain the information about whether the RNC, MME, and SGSN support the RIM procedure. Use these information to decide whether to perform load-based CSFB.
Table 7-1 Requirements of CSFB to UTRAN for the core networks
NE
Description
MME
Supports:
  • SGs interface to the MSC/VLR
  • VLR and LAI selection based on the TAI of the serving cell
  • MSC-initiated paging
  • PLMN selection and reselection
  • Combined EPS/IMSI attach, combined EPS/IMSI detach, and combined TAU/LAU
  • Routing of CS signaling messages
  • SMS over SGs
MSC
Supports:
  • Combined EPS/IMSI attach
  • SMS over SGs
  • Paging message forwarding over the SGs interface
SGSN
Does not activate ISR during the combined RAU/LAU procedure initiated by the UE.

7.1.3 Deployment

This section describes configuration, activation, and observation of TDLOFD-001033 CS Fallback to UTRAN.

7.1.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, ensure that the core network equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-2.
Table 7-2 License information for CSFB to UTRAN
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001033
CS Fallback to UTRAN
CS Fallback to UTRAN(TDD)
eNodeB
per RRC Connected User

7.1.3.2 Data Preparation

This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Collect scenario-specific data when necessary for a specific feature deployment scenario. You need to collect both required data and scenario-specific data based on requirements.
There are three types of data sources:
  • Network plan (negotiation not required): parameter values planned and set by the operator
  • Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment
  • User-defined: parameter values set by users
Required Data
Before configuring CSFB to UTRAN, collect the data related to neighbor relationships between E-UTRAN and UTRAN cells. This section provides only the information about MOs related to neighboring UTRAN cells. For details about how to collect data for the parameters in these MOs, see Mobility Management in Connected Mode Feature Parameter Description.
  1. UtranNFreq: used to configure neighboring UTRAN frequencies.
  2. UtranExternalCell: used to configure external UTRAN cells. If PS handover is used, the Rac parameter must be configured.
  3. UtranExternalCellPlmn: used to configure additional PLMN IDs for a shared external UTRAN cell. This MO is required only if the NodeB providing the external UTRAN cell works in RAN sharing with common carriers mode and multiple operators share the external UTRAN cell.
  4. UtranNCell: used to configure neighbor relationships between E-UTRAN and UTRAN cells. If a neighboring UTRAN cell supports blind handovers according to the network plan, the blind handover priority of the cell must be specified by the BlindHoPriority parameter.
Scenario-specific Data
The following table describes the parameters that must be set in the ENodeBAlgoSwitch MO to set the handover mode and handover algorithm switches for CSFB to UTRAN.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Mode switch
Network plan (negotiation not required)
Set this parameter based on the network plan.
To activate PS handovers, select the UtranPsHoSwitch(UtranPsHoSwitch) check box. If this check box is not selected, redirection will be used for CSFB to UTRAN.
To activate blind handovers, select the BlindHoSwitch(BlindHoSwitch) check box. A blind handover to an inter-RAT neighboring cell can be performed only if the blind handover priority is specified for the inter-RAT neighboring cell. Compared with measurement-based handovers, blind handovers have shorter access delays but a lower handover success rate.
Handover Algo switch
Network plan (negotiation not required)
To activate CSFB to UTRAN, select the UtranCsfbSwitch(UtranCsfbSwitch) check box.
If CSFB based on neighboring UTRAN cell loads is to be activated, select the CSFBLoadInfoSwitch(CSFBLoadInfoSwitch) check box.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the blind-handover priorities of different systems for CSFB.
Parameter Name
Parameter ID
Data Source
Setting Notes
CN Operator ID
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the ID of the operator whose inter-RAT blind-handover priorities are to be set.
Highest priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in blind handovers for CSFB. For CSFB to UTRAN, set this parameter to UTRAN.
Second priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the medium-priority system to be considered in blind handovers for CSFB. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
UTRAN LCS capability
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the LCS capability of the UTRAN.
The following table describes the parameters that must be set in the ENodeBAlgoSwitch MO to set the CSFB based on neighboring UTRAN cell loads.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Algo switch
Network plan (negotiation not required)
If CSFB based on neighboring UTRAN cell loads is to be activated, select the CSFBLoadInfoSwitch(CSFBLoadInfoSwitch) check box.
The following table describes the parameters that must be set in the GLOBALPROCSWITCH MO to select the transmission channel for UTRAN cell loads.
Parameter Name
Parameter ID
Data Source
Setting Notes
Choose UMTS Cell Load Info Trans Channel
Network plan (negotiation not required)
This parameter is set to Based on RIM if the UTRAN cell load must be obtained through the RIM procedure, and RCN, MME, and SGSN support RIM.
The following table describes the parameters that must be set in the CSFallBackHo MO to configure the CSFB protection timer.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB Protection Timer
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to 4 by default, which applies to operators who own GERAN, UTRAN, and E-UTRAN. For operators who own both UTRAN and E-UTRAN, this parameter can be set to 2. A large value affects the end-to-end delay in abnormal scenarios, and a small value may lead to interruption during measurement or handover.

7.1.3.3 Activation

Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs
Enter the values of the parameters listed in Table 7-3 in a summary data file, which also contains other data for the new eNodeBs to be deployed. Then, import the summary data file into the CME for batch configuration. For detailed instructions, see section "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB.
The summary data file may be a scenario-specific file provided by the CME or a customized file, depending on the following conditions:
  • The MOs in Table 7-3 are contained in a scenario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save the file.
  • Some MOs in Table 7-3 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters.
Table 7-3 Parameters for CSFB to UTRAN
MO
Sheet in the Summary Data File
Parameter Group
Remarks
UtranNFreq
UtranNFreq
Local cell identity and Downlink UARFCN
User-defined template
UtranExternalCell
UtranExternalCell
Mobile country code, Mobile network code, UTRAN cell identity, Downlink UARFCN, RNC identity, Primary scrambling code, and Location area code
User-defined template
UtranExternalCellPlmn
UtranExternalCellPlmn
UTRAN cell identity, Mobile country code, Mobile network code, Share mobile country code, and Share mobile network code
User-defined template
UtranNCell
UtranNCell
Local cell identity, Mobile country code, Mobile network code, UTRAN cell identity, and Blind handover priority
User-defined template
ENodeBAlgoSwitch
ENodeBAlgoSwitc
Handover Algo switch and Handover Mode switch
User-defined template
CSFallBackBlindHoCfg
CSFallBackBlindHoCfg
CN Operator ID, Highest priority InterRat, Second priority InterRat, and UTRAN LCS capability
User-defined template
CSFallBackHo
CSFallBackHo
Local cell ID and CSFB Protection Timer
User-defined template
Using the CME to Perform Batch Configuration for Existing eNodeBs
Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure is as follows:
  1. Choose CME > Advanced > Customize Summary Data File from the main menu of an M2000 client, or choose Advanced > Customize Summary Data File from the main menu of a CME client, to customize a summary data file for batch reconfiguration.
    NOTE:
    For context-sensitive help on a current task in the client, press F1.
  2. Choose CME > LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the CME client, to export the eNodeB data stored on the CME into the customized summary data file.
  3. In the summary data file, set the parameters in the MOs listed in "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs" and close the file.
  4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application> Import Data > Import Base Station Bulk Configuration Data from the main menu of the CME client, to import the summary data file into the CME.
  5. Choose CME > Planned Area > Export Incremental Scripts from the main menu of the M2000 client, or choose Area Management > Planned Area > Export Incremental Scripts from the main menu of the CME client, to export and activate the incremental scripts.
Using the CME to Perform Single Configuration
On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows:
  1. In the planned data area, click Base Station in the upper left corner of the configuration window.
  2. In area 1 shown in Figure 7-1, select the eNodeB to which the MOs belong.
    Figure 7-1 MO search and configuration window
  3. On the Search tab page in area 2, enter an MO name, for example, CELL.
  4. In area 3, double-click the MO in the Object Name column. All parameters in this MO are displayed in area 4.
  5. Set the parameters in area 4 or 5.
  6. Choose CME > Planned Area > Export Incremental Scripts (M2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.
Using MML Commands
  1. Run the following commands to add neighbor relationships between E-UTRAN and UTRAN cells:
    ADD UTRANNFREQ
    ADD UTRANEXTERNALCELL
    ADD UTRANEXTERNALCELLPLMN
    ADD UTRANNCELL
  2. Run the MOD ENODEBALGOSWITCH command to set the handover mode and handover algorithm switches for CSFB to UTRAN.
  3. Run the MOD CSFALLBACKBLINDHOCFG command to set the blind-handover priorities of different systems for CSFB.
  4. Run the MOD CSFallBackHo command to configure the CSFB protection timer.
  5. (Optional) Run the MOD ENODEBALGOSWITCH command with the CSFBLoadInfoSwitch check box selected under the Handover Algo switch parameter.
  6. (Optional) Run the MOD GLOBALPROCSWITCH command and set the Choose UMTS Cell Load Info Trans Channel parameter to Based on RIM.

7.1.3.4 Activation Observation

  1. Enable a UE to camp on an E-UTRAN cell and originate a voice call. The UE falls back to a UTRAN cell for voice services.
  2. Enable the UE to camp on the E-UTRAN cell and receive a voice call. The UE falls back to the UTRAN cell for voice services.
  3. If CSFB based on UTRAN cell loads is used, the verification procedure is as follows:
    Assume that there are two UTRAN cells represented by cell A and cell B, respectively. The RSCP of cell A is higher than that of cell B. The status of cell A is OLC and the status of cell B is Normal.
    Run the DSP UTRANRIMLOADINFO command to query load information of the specific eNodeB.
    After CSFB to UTRAN is activated, assume that PS handovers for CSFB are based on measurement. The eNodeB performs the following operations:
    If cells A and B both work properly, the eNodeB sends UEs the measurement configuration related to only cell B. If the RSCP of cell B meets handover requirements, the eNodeB enables UEs to fall back to cell B.
    If cell B is blocked, the eNodeB sends UEs the measurement configuration related to only cell A. If the RSCP of cell A meets handover requirements, the eNodeB enables UEs to fall back to cell A and ensures the access based on preemption and queuing policies.
Signaling Observation
  1. The CSFallbackIndicator IE contained in INITIAL CONTEXT SETUP REQ or UE_CONTEXT_MOD_REQ message is cs-fallback-required, indicating that CSFB has been initialized.
  2. After the eNodeB receives the CSFB indication, it selects the corresponding CSFB policies based on selection policies of neighboring cells and UE capabilities.
For UEs not supporting PS handovers, the eNodeB sends UEs the RRC Connection Release message containing redirectedCarrierInfo, which carries the UTRAN frequencies. The frequency configurations are consistent with those for the target CSFB cell.
For UEs supporting PS handovers, the eNodeB delivers event B1 contained in the RRC_CONN_RECONFIG message.
UEs trigger event B1 and the eNodeB delivers handover commands. The RRC_MOBIL_FROM_EUTRA_CMD message contains information about the target UTRAN cell.
Figure 7-2 and Figure 7-3 show sample procedures for CSFB to UTRAN for a mobile-originated call and CSFB to UTRAN for a mobile-terminated call, respectively. In the examples, the UE was in idle mode before the call and is forced to fall back to the UTRAN based on a redirection. Figure 7-4 shows UE CSFB to UTRAN by using the PS handover.
NOTE:
The UEs shown in the left and right sides of the figure are the same. This applies to all figures in the rest of this document. The messages on the UMTS side are only for reference.
Figure 7-2 CSFB to UTRAN for a mobile-originated call
Figure 7-3 CSFB to UTRAN for a mobile-terminated call
During the redirection, the eNodeB initiates a UE capability enquiry procedure if the UE capability is not included in the Initial Context Setup Request (Initial Context Setup Req in the figures) message received from the MME. If the UE capability is included, the eNodeB does not initiate this procedure.
If measurement-based redirection is used for CSFB to UTRAN, the eNodeB delivers the B1-related measurement configuration.
If blind redirection is used for CSFB to UTRAN, the eNodeB does not deliver the B1-related measurement configuration but sends an RRC Connection Release (RRC Conn Rel in the figures) message to the UE. The procedures indicated by dashed lines are optional.
If PS handover is used for CSFB to UTRAN, the eNodeB initiates a PS handover procedure after receiving a measurement report from the UE, instead of sending an RRC Connection Release message to the UE. Figure 7-4 shows the PS handover procedure.
Figure 7-4 PS handover procedure
Counter Observation
Table 7-4 lists the performance counters for observing functions related to CSFB to UTRAN.
Table 7-4 Performance counters for observing CSFB to UTRAN
Function
Counter ID
Counter Name
Description
CSFB to UTRAN
1526728323
L.CSFB.E2W
Number of procedures for CSFB to WCDMA network
CSFB to UTRAN triggered for emergency calls
1526728709
L.CSFB.E2W.Emergency
Number of procedures for CSFB to WCDMA network triggered for emergency calls
RIM during load-based CSFB to UTRAN
1526728949
L.RIM.Load.E2W.Req
Number of load requests from eNodeB to WCDMA network
1526728950
L.RIM.Load.E2W.Resp
Number of load responses from WCDMA network to eNodeB
1526728951
L.RIM.Load.E2W.Update
Number of load updates from eNodeB to WCDMA network

7.1.3.5 Deactivation

Using the CME to Perform Batch Configuration
Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that for feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 7-5.
Table 7-5 Parameters for CSFB to UTRAN
MO
Sheet in the Summary Data File
Parameter Group
Setting Notes
ENodeBAlgoSwitch
ENodeBAlgoSwitch
HoAlgoSwitch
UtranCsfbSwitch:Off
CSFBLoadInfoSwitch:Off
Using the CME to Perform Single Configuration
On the CME, set parameters according to Table 7-5. For detailed instructions, see Using the CME to Perform Single Configuration for feature activation.
Using MML Commands
Deactivating CSFB to UTRAN:
Run the MOD ENODEBALGOSWITCH command with the UtranCsfbSwitch(UtranCsfbSwitch) check box cleared under the HoAlgoSwitch parameter.
Only Deactivating UTRAN-cell-load-based CSFB:
Run the MOD ENODEBALGOSWITCH command with the CSFBLoadInfoSwitch(CSFBLoadInfoSwitch) check box cleared under the HoAlgoSwitch parameter.

7.1.3.6 MML Command Examples

NOTE:
The parameters in this section are for reference only. Configure the parameters depending on network requirements.
Activating CSFB to UTRAN
//To turn on the algorithm switch and handover switch, run the following command:
MOD ENODEBALGOSWITCH:HOALGOSWITCH=UtranCsfbSwitch-1,HOMODESWITCH=UtranPsHoSwitch-1&UtranRedirectSwitch-1&BlindHoSwitch-1;
NOTE:
Turn on the handover switch according to the network plan and UE capabilities to enable the CSFB mechanism.
To enable blind handovers, select the BlindHoSwitch check box.
//(Optional) Turn on the UTRAN-cell-load-based handover switch.
To enable CSFB based on UTRAN cell loads, run the following command with the CSFBLoadInfoSwitch and UTRAN_RIM_SWITCH check boxes selected:
MOD ENODEBALGOSWITCH:CSFBLoadInfoSwitch-1,RIMSWITCH=UTRAN_RIM_SWITCH-1;
MOD GLOBALPROCSWITCH: UtranLoadTransChan=BASED_ON_RIM;
//To configure a neighboring UTRAN frequency, run the following command:
ADD UTRANNFREQ:LOCALCELLID=0,UTRANDLARFCN=10700,UTRANVERSION=HSPA,UTRANFDDTDDTYPE=UTRAN_FDD,UTRANULARFCNCFGIND=NOT_CFG,CELLRESELPRIORITYCFGIND=NOT_CFG;
//To configure an external UTRAN cell, run the following command:
ADD UTRANEXTERNALCELL:MCC="460",MNC="14",RNCID=186,CELLID=203,UTRANDLARFCN=10700,UTRANULARFCNCFGIND=NOT_CFG,UTRANFDDTDDTYPE=UTRAN_FDD,RACCFGIND=NOT_CFG,PSCRAMBCODE=0,LAC=1313;
//To configure additional PLMN IDs for a shared external UTRAN cell, run the following command:
ADD UTRANEXTERNALCELLPLMN:MCC="460",MNC="14",RNCID=186,CELLID=203,SHAREMCC="460",SHAREMNC="13";
//To configure neighbor relationships between E-UTRAN and UTRAN cells, run the following command:
ADD UTRANNCELL:LOCALCELLID=0,MCC="460",MNC="14",RNCID=186,CELLID=203,BLINDHOPRIORITY=10;
//To enable a UE to preferentially fall back to the UTRAN, run the following command:
MOD CSFALLBACKBLINDHOCFG: CnOperatorId=0, InterRatHighestPri=UTRAN, InterRatSecondPri=GERAN, UtranLcsCap=ON;
Deactivating CSFB to UTRAN
//To disable CSFB to UTRAN, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=UtranCsfbSwitch-0;

7.2 TDLOFD-001034 CS Fallback to GERAN

7.2.1 When to Use CSFB to GERAN

Use TDLOFD-001034 CS Fallback to GERAN in the initial phase of LTE network deployment when both of the following conditions are met:
  • The operator owns a mature GERAN network.
  • The E-UTRAN does not provide VoIP services, or UEs in the E-UTRAN do not support VoIP services.
For policies on whether to use PS handover or PS redirection for CSFB, see Mobility Management in Connected Mode Feature Parameter Description. If the GERAN cell and E-UTRAN cell cover the same area, or the GERAN cell provides better coverage than the E-UTRAN cell, use CSFB based on blind handover to decrease the CSFB delay.

7.2.2 Required Information

  1. Collect the operating frequencies, coverage areas, and configurations of the E-UTRAN and GERAN cells.
  2. Collect the versions and configurations of the NEs in the E-UTRAN, GERAN, and core networks, and ensure that they all support CSFB. Table 7-6 describes the requirements of CSFB to GERAN for the core networks.
  3. Collect the following information about the UEs supporting GSM and LTE on the live network:
    • Supported frequency bands
    • Whether the UEs support redirection from E-UTRAN to GERAN
    • Whether the UEs support PS handovers from E-UTRAN to GERAN
    • Whether the UEs support GERAN measurements
    This information is used to configure neighboring GERAN cells and to determine whether to perform CSFB based on handover or redirection. For details, see Mobility Management in Connected Mode Feature Parameter Description.
Table 7-6 Requirements of CSFB to GERAN for the core networks
NE
Description
MME
Supports:
  • SGs interface to the MSC/VLR
  • VLR and LAI selection based on the TAI of the serving cell
  • MSC-initiated paging
  • PLMN selection and reselection
  • Combined EPS/IMSI attach, combined EPS/IMSI detach, and combined TAU/LAU
  • Routing of CS signaling messages
  • SMS over SGs
MSC
Supports:
  • Combined EPS/IMSI attach
  • SMS over SGs
  • Paging message forwarding over the SGs interface
SGSN
Does not activate ISR during the combined RAU/LAU procedure initiated by the UE.

7.2.3 Deployment

This section describes configuration, activation, and observation of TDLOFD-001034 CS Fallback to GERAN.

7.2.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, ensure that the core network equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-7.
Table 7-7 License information for CSFB to GERAN
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001034
CS Fallback to GERAN
CS Fallback to GERAN(TDD)
eNodeB
per RRC Connected User

7.2.3.2 Data Preparation

This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Collect scenario-specific data when necessary for a specific feature deployment scenario. You need to collect both required data and scenario-specific data based on requirements.
There are three types of data sources:
  • Network plan (negotiation not required): parameter values planned and set by the operator
  • Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment
  • User-defined: parameter values set by users
Required Data
Before configuring CSFB to GERAN, collect the data related to neighbor relationships with GERAN cells. This section provides only the information about MOs related to neighboring GERAN cells. For details about how to collect data for the parameters in these MOs, see Mobility Management in Connected Mode Feature Parameter Description.
  1. GeranNfreqGroup: used to configure GERAN carrier frequency groups.
  2. GeranNfreqGroupArfcn: used to configure absolute radio frequency channel numbers (ARFCNs) in each BCCH GERAN carrier frequency group.
  3. GeranExternalCell: used to configure external GERAN cells. If PS handover is used, the Rac parameter must be configured.
  4. GeranExternalCellPlmn: used to configure additional PLMN IDs for a shared external GERAN cell. This MO is required only if the NodeB providing the external GERAN cell works in RAN sharing with common carriers mode and multiple operators share the external GERAN cell for more than one hour.
  5. GeranNcell: used to configure neighbor relationships with GERAN cells. If a neighboring GERAN cell supports blind handovers according to the network plan, the blind handover priority of the cell must be specified by the BlindHoPriority parameter.
Scenario-specific Data
The following table describes the parameters that must be set in the ENodeBAlgoSwitch MO to set the handover mode and handover algorithm switches for CSFB to GERAN.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Mode switch
Network plan (negotiation not required)
Set this parameter based on the network plan.
To activate PS-handover-based CSFB, select the GeranPsHoSwitch(GeranPsHoSwitch) check box. To activate CCO-based CSFB, select the GeranCcoSwitch(GeranCcoSwitch) check box. To activate NACC-based CSFB, select the GeranNaccSwitch(GeranNaccSwitch) check box. If none of these check boxes is selected, redirection will be used for CSFB to GERAN.
To activate blind handovers, select the BlindHoSwitch(BlindHoSwitch) check box. A blind handover to an inter-RAT cell can be performed only if the blind handover priority is specified for the inter-RAT cell. Compared with measurement-based handovers, blind handovers have shorter access delays but a lower handover success rate.
Handover Algo switch
Network plan (negotiation not required)
To activate CSFB to GERAN, select the GeranCsfbSwitch(GeranCsfbSwitch) check box.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the blind-handover priorities of different systems for CSFB.
Parameter Name
Parameter ID
Data Source
Setting Notes
CN Operator ID
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the ID of the operator whose inter-RAT blind-handover priorities are to be set.
Highest priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in blind handovers for CSFB. For CSFB to GERAN, set this parameter to GERAN.
Second priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the medium-priority system to be considered in blind handovers for CSFB. If the Highest priority InterRat parameter is set to GERAN, this parameter cannot be set to GERAN. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
GERAN LCS capability
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the LCS capability of the GERAN.
The following table describes the parameters that must be set in the CSFallBackHo MO to configure the CSFB protection timer.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB Protection Timer
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to 4 by default, which applies to operators who own GERAN, UTRAN, and E-UTRAN. For operators who own GERAN and UTRAN, the default value is recommended. A large value affects the end-to-end delay in abnormal scenarios, and a small value may lead to interruption during measurement or handover.

7.2.3.3 Activation

Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs
Enter the values of the parameters listed in Table 7-8 in a summary data file, which also contains other data for the new eNodeBs to be deployed. Then, import the summary data file into the CME for batch configuration. For detailed instructions, see section "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB.
The summary data file may be a scenario-specific file provided by the CME or a customized file, depending on the following conditions:
  • The MOs in Table 7-8 are contained in a scenario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save the file.
  • Some MOs in Table 7-8 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters.
Table 7-8 Parameters for CSFB to GERAN
MO
Sheet in the Summary Data File
Parameter Group
Remarks
GeranNfreqGroup
GeranNfreqGroup
Local cell identity, BCCH group identity, GERAN version, Starting ARFCN, and Band indicator
User-defined template
GeranNfreqGroupArfcn
GeranNfreqGroupArfcn
Local cell identity, BCCH group identity, and GERAN ARFCN
User-defined template
GeranExternalCell
GeranExternalCell
Mobile country code, Mobile network code, GERAN cell identity, Location area code, Routing area code configure indicator, Band indicator, GERAN ARFCN, Network colour code, Base station colour code, and DTM indication
User-defined template
GeranExternalCellPlmn
GeranExternalCellPlmn
GERAN cell identity, Location area code, Mobile country code, Mobile network code, Share mobile country code, and Share mobile network code
User-defined template
GeranNcell
GeranNcell
Local cell identity, Mobile country code, Mobile network code, Location area code, GERAN cell identity, and Blind handover priority
User-defined template
ENodeBAlgoSwitch
ENodeBAlgoSwitch
Handover Algo switch, Handover Mode switch
User-defined template
CSFallBackBlindHoCfg
CSFallBackBlindHoCfg
CN Operator ID, Highest priority InterRat, Second priority InterRat, and GERAN LCS capability
User-defined template
CSFallBackHo
CSFallBackHo
Local cell ID, CSFB Protection Timer
User-defined template
Using the CME to Perform Batch Configuration for Existing eNodeBs
Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure is as follows:
  1. Choose CME > Advanced > Customize Summary Data File from the main menu of an M2000 client, or choose Advanced > Customize Summary Data File from the main menu of a CME client, to customize a summary data file for batch reconfiguration.
    NOTE:
    For context-sensitive help on a current task in the client, press F1.
  2. Choose CME > LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the CME client, to export the eNodeB data stored on the CME into the customized summary data file.
  3. In the summary data file, set the parameters in the MOs listed in "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs" and close the file.
  4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application> Import Data > Import Base Station Bulk Configuration Data from the main menu of the CME client, to import the summary data file into the CME.
  5. Choose CME > Planned Area > Export Incremental Scripts from the main menu of the M2000 client, or choose Area Management > Planned Area > Export Incremental Scripts from the main menu of the CME client, to export and activate the incremental scripts.
Using the CME to Perform Single Configuration
On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows:
  1. In the planned data area, click Base Station in the upper left corner of the configuration window.
  2. In area 1 shown in Figure 7-5, select the eNodeB to which the MOs belong.
    Figure 7-5 MO search and configuration window
  3. On the Search tab page in area 2, enter an MO name, for example, CELL.
  4. In area 3, double-click the MO in the Object Name column. All parameters in this MO are displayed in area 4.
  5. Set the parameters in area 4 or 5.
  6. Choose CME > Planned Area > Export Incremental Scripts (M2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.
Using MML Commands
  1. Run the following commands to add neighbor relationships between E-UTRAN and GERAN cells:
    • ADD GERANNFREQGROUP
    • ADD GERANNFREQGROUPARFCN
    • ADD GERANEXTERNALCELL
    • ADD GERANEXTERNALCELLPLMN
    • ADD GERANNCELL
  2. Run the MOD ENODEBALGOSWITCH command to set the handover mode and handover algorithm switches for CSFB to GERAN.
  3. Run the MOD CSFALLBACKBLINDHOCFG command to set the blind-handover priorities of different systems for CSFB.

7.2.3.4 Activation Observation

  1. Enable a UE to camp on an E-UTRAN cell and originate a voice call. The UE falls back to a GERAN cell for voice services.
  2. Enable the UE to camp on the E-UTRAN cell and receive a voice call. The UE falls back to the GERAN cell for voice services.
Signaling Observation
  1. The CSFallbackIndicator IE contained in INITIAL CONTEXT SETUP REQ or UE_CONTEXT_MOD_REQ message is cs-fallback-required, indicating that CSFB has been initialized.
  2. After the eNodeB receives the CSFB indication, it selects the corresponding CSFB policies based on selection policies of neighboring cells and UE capabilities.
For UEs not supporting PS-handover-based CSFB, the eNodeB sends UEs the RRC Connection Release message carrying redirectedCarrierInfo, which is consistent with frequency configurations of the target CSFB cell.
For UEs supporting PS-handover-based CSFB, the eNodeB delivers event B1 contained in the RRC_CONN_RECONFIG message. The UE reports event B1 and the eNodeB delivers handover commands. The RRC_MOBIL_FROM_EUTRA_CMD message contains information about the target GERAN cell.
The signaling procedure for CSFB to GERAN is similar to that for CSFB to UTRAN described in 7.1.3.4 Activation Observation.
Counter Observation
Verify that CSFB to GERAN has taken effect by observing the L.CSFB.E2G counter.

7.2.3.5 Deactivation

Using the CME to Perform Batch Configuration
Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that for feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 7-9.
Table 7-9 Parameters for CSFB to GERAN
MO
Sheet in the Summary Data File
Parameter Group
Setting Notes
ENodeBAlgoSwitch
ENodeBAlgoSwitch
HoAlgoSwitch
GeranCsfbSwitch:Off
Using the CME to Perform Single Configuration
On the CME, set parameters according to Table 7-9. For detailed instructions, see Using the CME to Perform Single Configuration for feature activation.
Using MML Commands
Run the MOD ENODEBALGOSWITCH command with the GeranCsfbSwitch(GeranCsfbSwitch) check box cleared under the HoAlgoSwitch parameter.

7.2.3.6 MML Command Examples

NOTE:
The parameters in this section are for reference only. Configure the parameters depending on network requirements.
Activating CSFB to GERAN
//To turn on the algorithm and handover switches, run the following commands:
MOD ENODEBALGOSWITCH:HOALGOSWITCH=GeranCsfbSwitch-1,HOMODESWITCH=GeranPsHoSwitch-1&GeranRedirectSwitch-1&BlindHoSwitch-1;
NOTE:
Turn on the handover switch according to the network plan and UE capabilities to enable the CSFB mechanism.
To enable blind handovers, select the BlindHoSwitch check box.
//To configure the GERAN frequency group, run the following command:
ADD GERANNFREQGROUP:LOCALCELLID=0,BCCHGROUPID=0,GERANVERSION=GSM,STARTINGARFCN=90,BANDINDICATOR=GSM_dcs1800,CELLRESELPRIORITYCFGIND=NOT_CFG,PMAXGERANCFGIND=NOT_CFG;
//To configure the frequency in the GERAN frequency group, run the following command:
ADD GERANNFREQGROUPARFCN:LOCALCELLID=0,BCCHGROUPID=0,GERANARFCN=700;
//To configure an external GERAN cell, run the following command:
ADD GERANEXTERNALCELL:MCC="460",MNC="14",GERANCELLID=8,LAC=1313,RACCFGIND=CFG,RAC=0,BANDINDICATOR=GSM_dcs1800,GERANARFCN=90,NETWORKCOLOURCODE=0,BASESTATIONCOLOURCODE=0,DTMIND=DTM_AVAILABLE;
//To configure additional PLMN IDs for a shared external GERAN cell, run the following command:
ADD GERANEXTERNALCELLPLMN: GeranCellId=0, Lac=1313, Mcc="460", Mnc="14", ShareMcc="460", ShareMnc="13";
//To configure neighbor relationships between E-UTRAN and GERAN cells, run the following command:
ADD GERANNCELL:LOCALCELLID=0,MCC="460",MNC="14",LAC=1313,GERANCELLID=8,BLINDHOPRIORITY=10;
//To configure the CSFB priority, run the following command:
MOD CSFALLBACKBLINDHOCFG: CnOperatorId=0, InterRatHighestPri=GERAN, InterRatSecondPri=UTRAN, GeranLcsCap=ON;
Deactivating CSFB to GERAN
//To deactivate CSFB to GERAN, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=GeranCsfbSwitch-0;

7.3 TDLOFD-001052 Flash CS Fallback to UTRAN

7.3.1 When to Use Flash CSFB to UTRAN

When TDLOFD-001033 CS Fallback to UTRAN has been enabled, use TDLOFD-001052 Flash CS Fallback to UTRAN if all the following conditions are met:
  • The E-UTRAN and UTRAN support the RIM with SIB procedure.
  • UEs comply with 3GPP Release 9.
  • The core networks support the RIM procedure.
For policies on whether to use PS handover or PS redirection for CSFB, see Mobility Management in Connected Mode Feature Parameter Description. If the UTRAN cell and E-UTRAN cell cover the same area, or the UTRAN cell provides better coverage than the E-UTRAN cell, use CSFB based on blind handover to decrease the CSFB delay.

7.3.2 Required Information

  1. Collect the operating frequencies, coverage areas, and configurations of the E-UTRAN and UTRAN cells.
  2. Collect the versions and configurations of the NEs in the E-UTRAN, UTRAN, and core networks, and ensure that they all support CSFB and the RIM procedure. Table 7-10 describes the requirements of flash CSFB to UTRAN for the core networks.
  3. Table 7-11 describes the requirements of flash CSFB to UTRAN for the UTRAN.
  4. Collect the following information about the UEs supporting UMTS and LTE on the live network:
    • Supported frequency bands
    • Whether the UEs support redirection from E-UTRAN to UTRAN
    • Whether the UEs support PS handovers from E-UTRAN to UTRAN
    • Whether the UEs support UTRAN measurements
    • Whether the UEs comply with the 3GPP Release 9
    This information is used to configure neighboring UTRAN cells and to determine whether to perform CSFB based on handover or redirection. For details, see Mobility Management in Connected Mode Feature Parameter Description.
Table 7-10 Requirements of flash CSFB to UTRAN for the core networks
NE
Description
MME
Supports:
  • CSFB basic functions
  • RIM procedures
SGSN
Supports:
  • CSFB basic functions
  • RIM procedures
Table 7-11 Requirements of flash CSFB to UTRAN for the UTRAN
NE
Description
RNC
RIM procedures

7.3.3 Deployment

This section describes configuration, activation, and observation of TDLOFD-001052 Flash CS Fallback to UTRAN.

7.3.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, ensure that the core network equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-12.
Table 7-12 License information for flash CSFB to UTRAN
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001033
CS Fallback to UTRAN
CS Fallback to UTRAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001052
Flash CS Fallback to UTRAN
Flash CS Fallback to UTRAN(TDD)
eNodeB
per RRC Connected User
NOTE:
If PS handover for CSFB to UTRAN is enabled, CSFB to UTRAN based on PS handover instead of flash CSFB to UTRAN is used for UEs that support PS handovers. For details, see 5.3 Features Related to TDLOFD-001052 Flash CS Fallback to UTRAN.

7.3.3.2 Data Preparation

This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Collect scenario-specific data when necessary for a specific feature deployment scenario. You need to collect both required data and scenario-specific data based on requirements.
There are three types of data sources:
  • Network plan (negotiation not required): parameter values planned and set by the operator
  • Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment
  • User-defined: parameter values set by users
Required Data
Before configuring CSFB to UTRAN, collect the data related to neighbor relationships between E-UTRAN and UTRAN cells. This section provides only the information about MOs related to neighboring UTRAN cells and key parameters in these MOs. For details about how to collect data for the parameters in these MOs, see Mobility Management in Connected Mode Feature Parameter Description.
  1. UtranNFreq: used to configure neighboring UTRAN frequencies.
  2. UtranExternalCell: used to configure external UTRAN cells. If PS handover is used, the Rac parameter must be configured.
  3. UtranExternalCellPlmn: used to configure additional PLMN IDs for a shared external UTRAN cell. This MO is required only if the NodeB providing the external UTRAN cell works in RAN sharing with common carriers mode and multiple operators share the external UTRAN cell.
  4. UtranNCell: used to configure neighbor relationships between E-UTRAN and UTRAN cells. If a neighboring UTRAN cell supports blind handovers according to the network plan, the blind handover priority of the cell must be specified by the BlindHoPriority parameter.
  5. S1Interface: used to configure the S1 interface that works in compliance with the Release 9. The MmeRelease must be set to Release_R9.
Scenario-specific Data
The following table describes the parameters that must be set in the ENodeBAlgoSwitch MO to set the handover mode and handover algorithm switches for flash CSFB to UTRAN.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Mode switch
Network plan (negotiation not required)
Set this parameter based on the network plan.
To activate blind handovers, select the BlindHoSwitch(BlindHoSwitch) check box. A blind handover to an inter-RAT cell can be performed only if the blind handover priority is specified for the inter-RAT cell. Compared with measurement-based handovers, blind handovers have shorter access delays but a lower handover success rate.
Handover Algo switch
Network plan (negotiation not required)
To activate flash CSFB to UTRAN, select the UtranCsfbSwitch(UtranCsfbSwitch) and UtranFlashCsfbSwitch(UtranFlashCsfbSwitch) check boxes.
RIM switch
Network plan (negotiation not required)
UTRAN_RIM_SWITCH under this parameter specifies whether to enable or disable the RIM procedure that requests event-driven multiple reports from UTRAN cells.
If this switch is turned on, the eNodeB can send RAN-INFORMATION-REQUEST/Multiple Report protocol data units (PDUs) to UTRAN cells to request event-driven multiple reports.
If this switch is turned off, the eNodeB cannot send RAN-INFORMATION-REQUEST/Multiple Report PDUs to UTRAN cells.
If this switch is turned off and the UtranFlashCsfbSwitch check box under the HoAlgoSwitch parameter is selected, the eNodeB sends RAN-INFORMATION-REQUEST/Single Report PDUs to UTRAN cells to request single reports.
If the UTRAN cells support RAN-INFORMATION-REQUEST/Multiple Report PDUs, it is recommended that you select the UTRAN_RIM_SWITCH(UTRAN_RIM_SWITCH) check box.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the blind-handover priorities of different systems for CSFB.
Parameter Name
Parameter ID
Data Source
Setting Notes
CN Operator ID
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the ID of the operator whose inter-RAT blind-handover priorities are to be set.
Highest priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in blind handovers for CSFB. For CSFB to UTRAN, set this parameter to UTRAN.
Second priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the medium-priority system to be considered in blind handovers for CSFB. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
UTRAN LCS capability
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the LCS capability of the UTRAN.
The following table describes the parameters that must be set in the InterRatHoComm MO to set the number of system messages containing target cells during a flash redirection procedure.
Parameter Name
Parameter ID
Data Source
Setting Notes
Max Utran cell num in redirection
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to 8 by default. A small value of this parameter leads to a low probability of SIB mappings, which decreases the success rate of flash CSFB to UTRAN. A large value of this parameter leads to a large size of the RRC connection Release message, which may fail to be sent in certain scenarios. This also decreases the CSFB success rate.
If adaptive blind CSFB is required, the following parameters must be set.
The following table describes the parameters in the ENodeBAlgoSwitch MO that must be configured to set the blind handover mode and adaptive blind handover algorithm switches.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Mode switch
Network plan (negotiation not required)
Select the BlindHoSwitch check box.
Handover Algo switch
Network plan (negotiation not required)
Select the CsfbAdaptiveBlindHoSwitch(CsfbAdaptiveBlindHoSwitch) check box.
The following table describes the parameters in the CSFallBackHo MO that must be configured to set the RSRP threshold used to report event A1 for adaptive blind handovers.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB Adaptive Blind Ho A1 RSRP Trigger Threshold
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is used to distinguish cell center users (CCUs) from cell edge users (CEUs). Blind handovers are performed only for CCUs. Therefore, operators must balance the CSFB success rate and delay, and set the overlapping coverage area of cells as the cell center.

7.3.3.3 Activation

Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs
Enter the values of the parameters listed in Table 7-13 in a summary data file, which also contains other data for the new eNodeBs to be deployed. Then, import the summary data file into the CME for batch configuration. For detailed instructions, see section "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB.
The summary data file may be a scenario-specific file provided by the CME or a customized file, depending on the following conditions:
  • The MOs in Table 7-13 are contained in a scenario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save the file.
  • Some MOs in Table 7-13 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters.
Table 7-13 Parameters for flash CSFB to UTRAN
MO
Sheet in the Summary Data File
Parameter Group
Remarks
UtranNFreq
UtranNFreq
Local cell identity/Downlink UARFCN
User-defined template
UtranExternalCell
UtranExternalCell
Mobile country code, Mobile network code, UTRAN cell identity, Downlink UARFCN, RNC identity, Routing area code configure indicator, Routing area code, Primary scrambling code, and Location area code
User-defined template
UtranExternalCellPlmn
UtranExternalCellPlmn
UTRAN cell identity, Mobile country code, Mobile network code, Share mobile country code, and Share mobile network code
User-defined template
UtranNCell
UtranNCell
Local cell identity, Mobile country code, Mobile network code, UTRAN cell identity, and Blind handover priority
User-defined template
ENodeBAlgoSwitch
ENodeBAlgoSwitch
Handover Algo switch, Handover Mode switch, Redirection switch, and RIM switch
User-defined template
CSFallBackBlindHoCfg
CSFallBackBlindHoCfg
CN Operator ID, Highest priority InterRat, Second priority InterRat, and UTRAN LCS capability
User-defined template
InterRatHoComm
InterRatHoComm
Max Utran cell num in redirection
User-defined template
CSFallBackHo
CSFallBackHo
Local cell ID and CSFB Adaptive Blind Ho A1 RSRP Trigger Threshold
User-defined template
S1Interface
S1InterfacePattern
S1Interface ID and MME Release
User-defined template
Using the CME to Perform Batch Configuration for Existing eNodeBs
Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure is as follows:
  1. Choose CME > Advanced > Customize Summary Data File from the main menu of an M2000 client, or choose Advanced > Customize Summary Data File from the main menu of a CME client, to customize a summary data file for batch reconfiguration.
    NOTE:
    For context-sensitive help on a current task in the client, press F1.
  2. Choose CME > LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the CME client, to export the eNodeB data stored on the CME into the customized summary data file.
  3. In the summary data file, set the parameters in the MOs listed in "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs" and close the file.
  4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application> Import Data > Import Base Station Bulk Configuration Data from the main menu of the CME client, to import the summary data file into the CME.
  5. Choose CME > Planned Area > Export Incremental Scripts from the main menu of the M2000 client, or choose Area Management > Planned Area > Export Incremental Scripts from the main menu of the CME client, to export and activate the incremental scripts.
Using the CME to Perform Single Configuration
On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows:
  1. In the planned data area, click Base Station in the upper left corner of the configuration window.
  2. In area 1 shown in Figure 7-6, select the eNodeB to which the MOs belong.
    Figure 7-6 MO search and configuration window
  3. On the Search tab page in area 2, enter an MO name, for example, CELL.
  4. In area 3, double-click the MO in the Object Name column. All parameters in this MO are displayed in area 4.
  5. Set the parameters in area 4 or 5.
  6. Choose CME > Planned Area > Export Incremental Scripts (M2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.
Using MML Commands
  1. Run the following commands to add neighbor relationships between E-UTRAN and UTRAN cells:
    ADD UTRANNFREQ
    ADD UTRANEXTERNALCELL
    ADD UTRANEXTERNALCELLPLMN
    ADD UTRANNCELL
  2. Run the MOD ENODEBALGOSWITCH command to set the handover mode, handover algorithm switches, redirection algorithm switch, and RIM procedure switch for flash CSFB to UTRAN.
  3. Run the MOD CSFALLBACKBLINDHOCFG command to set the blind-handover priorities of different systems for CSFB.
  4. Run the MOD S1INTERFACE command to set the MME version.
  5. Run the MOD InterRatHoComm command to configure the maximum number of cells in the UTRAN to which redirection-based flash CSFB is to be performed.
Perform the following operations to enable the adaptive blind CSFB:
  1. Run the MOD ENODEBALGOSWITCH command to configure the blind handover and CSFB adaptive blind handover switches.
  2. Run the MOD CSFallBackHo command to configure the RSRP threshold used to report event A1 for adaptive blind handovers.

7.3.3.4 Activation Observation

Signaling Observation
Deployment of Flash CSFB to UTRAN Based on MultiRIM
  1. Obtain the UTRAN information from the RIM procedure.
    For the RIM procedure in Multiple Report mode, the eNodeB exchanges the DIRECT_INFO_TRANSF message with the MME. By doing this, the eNodeB obtains the SI of the UTRAN.
  2. Query RIM information.
    After message exchanges, run the DSP UTRANRIMINFO command to query the RIM status of neighboring UTRAN cells. If the cell ID is displayed in the queried result, the eNodeB has obtained the SI of the neighboring UTRAN cells.
  3. Perform flash CSFB to UTRAN.
    Enable a UE to camp on an E-UTRAN cell and originate a voice call. If the call continues and the RRC Connection Release message traced on the Uu interface carries the information about the neighboring UTRAN cell, flash CSFB to UTRAN has been activated successfully. If the eNodeB obtains the system information of multiple UTRAN cells and the frequency selected by the eNodeB serves multiple UTRAN cells, the RRC Connection Release message carries the cell information of multiple SIBs, as described in the following messages:
Deployment of Flash CSFB to UTRAN Based on SingleRIM
  1. Obtain the UTRAN information from the RIM procedure.
    Enable a UE to camp on an E-UTRAN cell and originate a voice call. After receiving a CSFB indication from the MME, the eNodeB sends a RIM request message to obtain the system information.
  2. Perform flash CSFB to UTRAN.
    If the call continues and the RRC Connection Release message traced on the Uu interface carries the information about the neighboring UTRAN cell, flash CSFB to UTRAN has been activated successfully.
Counter Observation
Table 7-14 lists the performance counters for observing functions related to flash CSFB to UTRAN.
Table 7-14 Performance counters for observing flash CSFB to UTRAN
Function
Counter ID
Counter Name
Description
Flash CSFB to UTRAN
1526728705
L.FlashCSFB.E2W
Number of procedures for flash CSFB to WCDMA network
RIM during flash CSFB to UTRAN
1526728946
L.RIM.SI.E2W.Req
Number of system information requests from eNodeB to WCDMA network
1526728947
L.RIM.SI.E2W.Resp
Number of system information responses from WCDMA network to eNodeB
1526728948
L.RIM.SI.E2W.Update
Number of system information updates from eNodeB to WCDMA network

7.3.3.5 Deactivation

Using the CME to Perform Batch Configuration
Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that for feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 7-15.
Table 7-15 Parameters for CSFB to UTRAN
MO
Sheet in the Summary Data File
Parameter Group
Setting Notes
ENodeBAlgoSwitch
ENodeBAlgoSwitch
HoAlgoSwitch
UtranFlashCsfbSwitch:Off
Using the CME to Perform Single Configuration
On the CME, set parameters according to Table 7-15. For detailed instructions, see Using the CME to Perform Single Configuration for feature activation.
Using MML Commands
Run the MOD ENODEBALGOSWITCH command with the UtranFlashCsfbSwitch(UtranFlashCsfbSwitch) check box cleared under the HoAlgoSwitch parameter.

7.3.3.6 MML Command Examples

NOTE:
The parameters in this section are for reference only. Configure the parameters depending on network requirements.
Activating Flash CSFB to UTRAN
The flash CSFB to UTRAN feature requires the CSFB to UTRAN feature. For details about the basic configuration, see Activating CSFB to UTRAN. For details about the configuration related to flash CSFB to UTRAN, refer to the following commands.
//To turn on the algorithm switch and handover switch, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=UtranFlashCsfbSwitch-1&CsfbAdaptiveBlindHoSwitch-1,HoModeSwitch=RimSwitch=UTRAN_RIM_SWITCH-1;
NOTE:
Select the UtranFlashCsfbSwitch(UtranFlashCsfbSwitch) check box.
To enable CSFB based on the RIM procedure in Multiple Report mode, select the UTRAN_RIM_SWITCH(UTRAN RIM Switch) check box; to enable CSFB based on the RIM procedure in Single Report mode, keep the UTRAN_RIM_SWITCH(UTRAN RIM Switch) check box cleared.
To enable CSFB based on the adaptive blind handover, select the CsfbAdaptiveBlindHoSwitch(CsfbAdaptiveBlindHoSwitch) check box.
//To set the MME version for the S1 interface, run the following command:
MOD S1INTERFACE: S1InterfaceId=0, MmeRelease=Release_R9;
//To set the A1 threshold for adaptive blind handovers, run the following command:
MOD CSFALLBACKHO: LocalCellId=0, BlindHoA1ThdRsrp=-95;
//To set the maximum number of UTRAN cells, run the following command:
MOD INTERRATHOCOMM: CellInfoMaxUtranCellNum=16;
Deactivating Flash CSFB to UTRAN
//To deactivate flash CSFB to UTRAN, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=UtranFlashCsfbSwitch-0;

7.4 TDLOFD-001053 Flash CS Fallback to GERAN

7.4.1 When to Use Flash CSFB to GERAN

When TDLOFD-001034 CS Fallback to GERAN has been enabled, use TDLOFD-001053 Flash CS Fallback to GERAN if all the following conditions are met:
  • The E-UTRAN and UTRAN support the RIM with SIB procedure.
  • UEs comply with 3GPP Release 9.
  • The core networks support the RIM procedure.
For policies on whether to use PS handover or PS redirection for CSFB, see Mobility Management in Connected Mode Feature Parameter Description. If the GERAN cell and E-UTRAN cell cover the same area, or the GERAN cell provides better coverage than the E-UTRAN cell, use CSFB based on blind handover to decrease the CSFB delay.

7.4.2 Required Information

  1. Collect the operating frequencies, coverage areas, and configurations of the E-UTRAN and GERAN cells.
  2. Collect the versions and configurations of the NEs in the E-UTRAN, GERAN, and core networks, and ensure that they all support CSFB and the RIM procedure. Table 7-16 describes the requirements of CSFB to GERAN for the core networks.
  3. Table 7-17 describes the requirements of flash CSFB to GERAN for the UTRAN.
  4. Collect the following information about the UEs supporting UMTS and LTE on the live network:
    • Supported frequency bands
    • Whether the UEs support redirection from E-UTRAN to GERAN
    • Whether the UEs support PS handovers from E-UTRAN to GERAN
    • Whether the UEs support GERAN measurements
    • Whether the UEs comply with the 3GPP Release 9
    This information is used to configure neighboring GERAN cells and to determine whether to perform CSFB based on handover or redirection. For details, see Mobility Management in Connected Mode Feature Parameter Description.
Table 7-16 Requirements of flash CSFB to GERAN for the core networks
NE
Description
MME
Supports:
  • CSFB basic functions
  • RIM procedures
SGSN
Supports:
  • CSFB basic functions
  • RIM procedures
Table 7-17 Requirements of flash CSFB to GERAN for the GERAN
NE
Description
BSC
RIM procedures

7.4.3 Deployment

This section describes configuration, activation, and observation of TDLOFD-001053 Flash CS Fallback to GERAN.

7.4.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, ensure that the core network equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-18.
Table 7-18 License information for flash CSFB to GERAN
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001034
CS Fallback to GERAN
CS Fallback to GERAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001053
Flash CS Fallback to GERAN
Flash CS Fallback to GERAN(TDD)
eNodeB
per RRC Connected User
NOTE:
If PS handover for CSFB to GERAN is enabled, CSFB to GERAN based on PS handover instead of flash CSFB to GERAN is used for UEs that support PS handovers. For details, see 5.4 Features Related to TDLOFD-001053 Flash CS Fallback to GERAN.

7.4.3.2 Data Preparation

This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Collect scenario-specific data when necessary for a specific feature deployment scenario. You need to collect both required data and scenario-specific data based on requirements.
There are three types of data sources:
  • Network plan (negotiation not required): parameter values planned and set by the operator
  • Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment
  • User-defined: parameter values set by users
Required Data
Before configuring CSFB to GERAN, collect the data related to neighbor relationships between E-UTRAN and GERAN cells. This section provides only the information about MOs related to neighboring GERAN cells and key parameters in these MOs. For details about how to collect data for the parameters in these MOs, see Mobility Management in Connected Mode Feature Parameter Description.
  1. GeranNfreqGroup: used to configure neighboring GERAN frequencies.
  2. GeranNfreqGroupArfcn: used to configure neighboring GERAN BCCH frequencies.
  3. GeranExternalCell: used to configure external GERAN cells. The Rac parameter must be configured. If multiple external GERAN cells on the same frequency are configured, the eNodeB sends the system information of multiple external GERAN cells to the UE based on frequency selection policy.
  4. GeranExternalCellPlmn: used to configure additional PLMN IDs for a shared external GERAN cell. This MO is required only if the NodeB providing the external GERAN cell works in RAN sharing with common carriers mode and multiple operators share the external GERAN cell for more than one hour.
  5. GeranNcell: used to configure neighbor relationships between E-UTRAN and GERAN cells. If a neighboring GERAN cell supports blind handovers according to the network plan, the blind handover priority of the cell must be specified by the BlindHoPriority parameter.
  6. S1Interface: used to configure the S1 interface that works in compliance with the Release 9. The MmeRelease must be set to Release_R9.
Scenario-specific Data
The following table describes the parameters that must be set in the ENodeBAlgoSwitch MO to set the handover mode and handover algorithm switches for flash CSFB to GERAN.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Mode switch
Network plan (negotiation not required)
Set this parameter based on the network plan.
To activate blind handovers, select the BlindHoSwitch(BlindHoSwitch) check box. A blind handover to an inter-RAT cell can be performed only if the blind handover priority is specified for the inter-RAT cell. Compared with measurement-based handovers, blind handovers have shorter access delays but a lower handover success rate.
Handover Algo switch
Network plan (negotiation not required)
To activate flash CSFB to GERAN, select the GeranCsfbSwitch(GeranCsfbSwitch) and GeranFlashCsfbSwitch(GeranFlashCsfbSwitch) check boxes.
RIM switch
Network plan (negotiation not required)
GERAN_RIM_SWITCH under this parameter specifies whether to enable or disable the RIM procedure that requests event-driven multiple reports from GERAN cells.
If this switch is turned on, the eNodeB can send RAN-INFORMATION-REQUEST/Multiple Report PDUs to GERAN cells to request event-driven multiple reports.
If this switch is turned off, the eNodeB cannot send RAN-INFORMATION-REQUEST/Multiple Report PDUs to GERAN cells.
If this switch is turned off and the GeranFlashCsfbSwitch check box under the HoAlgoSwitch parameter is selected, the eNodeB sends RAN-INFORMATION-REQUEST/Single Report PDUs to GERAN cells to request single reports.
If the GERAN cells support RAN-INFORMATION-REQUEST/Multiple Report PDUs, it is recommended that you select the GERAN_RIM_SWITCH(GERAN_RIM_SWITCH) check box.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the blind-handover priorities of different systems for CSFB.
Parameter Name
Parameter ID
Data Source
Setting Notes
CN Operator ID
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the ID of the operator whose inter-RAT blind-handover priorities are to be set.
Highest priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in blind handovers for CSFB. For flash CSFB to GERAN, set this parameter to GERAN.
Second priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the medium-priority system to be considered in blind handovers for CSFB. If the Highest priority InterRat parameter is set to GERAN, this parameter cannot be set to GERAN. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
GERAN LCS capability
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the LCS capability of the GERAN.
The following table describes the parameters that must be set in the InterRatHoComm MO to set the number of system messages containing target cells during a flash redirection procedure.
Parameter Name
Parameter ID
Data Source
Setting Notes
Max Geran cell num in redirection
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to 8 by default. A small value of this parameter leads to a low probability of SIB mappings, which decreases the success rate of flash CSFB to UTRAN. A large value of this parameter leads to a large size of the RRC connection Release message, which may fail to be sent in certain scenarios. This also decreases the CSFB success rate.
If adaptive blind CSFB is required, the following parameters must be set.
The following table describes the parameters in the ENodeBAlgoSwitch MO that must be configured to set the blind handover mode and adaptive blind handover algorithm switches.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Mode switch
Network plan (negotiation not required)
Select the BlindHoSwitch check box.
Handover Algo switch
Network plan (negotiation not required)
Select the CsfbAdaptiveBlindHoSwitch(CsfbAdaptiveBlindHoSwitch) check box.
The following table describes the parameters in the CSFallBackHo MO that must be configured to set the RSRP threshold used to report event A1 for adaptive blind handovers.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB Adaptive Blind Ho A1 RSRP Trigger Threshold
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is used to distinguish CCUs from CEUs. Blind handovers are performed only for CCUs. Therefore, operators must balance the CSFB success rate and delay, and set the overlapping coverage area of cells as the cell center.

7.4.3.3 Activation

Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs
Enter the values of the parameters listed in Table 7-19 in a summary data file, which also contains other data for the new eNodeBs to be deployed. Then, import the summary data file into the CME for batch configuration. For detailed instructions, see section "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB.
The summary data file may be a scenario-specific file provided by the CME or a customized file, depending on the following conditions:
  • The MOs in Table 7-19 are contained in a scenario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save the file.
  • Some MOs in Table 7-19 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters.
Table 7-19 Parameters for flash CSFB to GERAN
MO
Sheet in the Summary Data File
Parameter Group
Remarks
GeranNfreqGroup
GeranNfreqGroup
Local cell identity, BCCH group identity, GERAN version, Starting ARFCN, and Band indicator
User-defined template
GeranNfreqGroupArfcn
GeranNfreqGroupArfcn
Local cell identity, BCCH group identity, and GERAN ARFCN
User-defined template
GeranExternalCell
GeranExternalCell
Mobile country code, Mobile network code, GERAN cell identity, Location area code, Routing area code configure indicator, Routing area code, Band indicator, GERAN ARFCN, Network colour code, Base station colour code, and DTM indication
User-defined template
GeranExternalCellPlmn
GeranExternalCellPlmn
GERAN cell identity, Location area code, Mobile country code, Mobile network code, Share mobile country code, and Share mobile network code
User-defined template
GeranNcell
GeranNcell
Local cell identity, Mobile country code, Mobile network code, Location area code, GERAN cell identity, and Blind handover priority
User-defined template
ENodeBAlgoSwitch
ENodeBAlgoSwitch
Handover Algo switch, Handover Mode switch, Redirection switch, RIM switch, and BlindHoSwitchCsfbAdaptiveBlindHoSwitch
User-defined template
CSFallBackBlindHoCfg
CSFallBackBlindHoCfg
CN Operator ID, Highest priority InterRat, Second priority InterRat, and GERAN LCS capability
User-defined template
InterRatHoComm
InterRatHoComm
Max Geran cell num in redirection
User-defined template
CSFallBackHo
CSFallBackHo
Local cell ID and CSFB Adaptive Blind Ho A1 RSRP Trigger Threshold
User-defined template
S1Interface
S1InterfacePattern
S1Interface ID and MME Release
User-defined template
Using the CME to Perform Batch Configuration for Existing eNodeBs
Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure is as follows:
  1. Choose CME > Advanced > Customize Summary Data File from the main menu of an M2000 client, or choose Advanced > Customize Summary Data File from the main menu of a CME client, to customize a summary data file for batch reconfiguration.
    NOTE:
    For context-sensitive help on a current task in the client, press F1.
  2. Choose CME > LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the CME client, to export the eNodeB data stored on the CME into the customized summary data file.
  3. In the summary data file, set the parameters in the MOs listed in "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs" and close the file.
  4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application> Import Data > Import Base Station Bulk Configuration Data from the main menu of the CME client, to import the summary data file into the CME.
  5. Choose CME > Planned Area > Export Incremental Scripts from the main menu of the M2000 client, or choose Area Management > Planned Area > Export Incremental Scripts from the main menu of the CME client, to export and activate the incremental scripts.
Using the CME to Perform Single Configuration
On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows:
  1. In the planned data area, click Base Station in the upper left corner of the configuration window.
  2. In area 1 shown in Figure 7-7, select the eNodeB to which the MOs belong.
    Figure 7-7 MO search and configuration window
  3. On the Search tab page in area 2, enter an MO name, for example, CELL.
  4. In area 3, double-click the MO in the Object Name column. All parameters in this MO are displayed in area 4.
  5. Set the parameters in area 4 or 5.
  6. Choose CME > Planned Area > Export Incremental Scripts (M2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.
Using MML Commands
  1. Run the following commands to add neighbor relationships between E-UTRAN and GERAN cells:
    ADD GERANNFREQGROUP
    ADD GERANNFREQGROUPARFCN
    ADD GERANEXTERNALCELL
    ADD GERANEXTERNALCELLPLMN
    ADD GERANNCELL
  2. Run the MOD ENODEBALGOSWITCH command to set the handover mode, handover algorithm switches, redirection algorithm switch, and RIM procedure switch for flash CSFB to GERAN.
  3. Run the MOD CSFALLBACKBLINDHOCFG command to set the blind-handover priorities of different systems for CSFB.
  4. Run the MOD S1INTERFACE command to set the MME version.
  5. Run the MOD InterRatHoComm command to configure the maximum number of cells in the GERAN to which redirection-based flash CSFB is to be performed.
Perform the following operations to enable the adaptive blind CSFB:
  1. Run the MOD ENODEBALGOSWITCH command to configure the blind handover and CSFB adaptive blind handover switches.
  2. Run the MOD CSFallBackHo command to configure the RSRP threshold used to report event A1 for adaptive blind handovers.

7.4.3.4 Activation Observation

Deployment of Flash CSFB to GERAN Based on MultiRIM
  1. Obtain the GERAN information from the RIM procedure.
    For the RIM procedure in Multiple Report mode, the eNodeB exchanges the DIRECT_INFO_TRANSF message with the MME. By this means, the eNodeB obtains the RIM information of the GERAN. The GERAN notifies the eNodeB of system information change if any.
  2. Query RIM information.
    After message exchanges, run the DSP GERANRIMINFO command to query the RIM status of neighboring GERAN cells. If the cell ID can be found from the queried result, the eNodeB has obtained the system information of the neighboring GERAN cells.
  3. Perform flash CSFB to GERAN.
    Enable a UE to camp on an E-UTRAN cell and originate a voice call. If the call continues and the RRC Connection Release message traced on the Uu interface carries the information about the neighboring GERAN cell, flash CSFB to GERAN has been activated successfully. If the eNodeB obtains the system information of multiple GERAN cells and the frequency selected by the eNodeB serves multiple GERAN cells, the RRC Connection Release message carries the cell information of multiple SIBs, as described in the following messages: as described in the following messages:
Deployment of Flash CSFB to GERAN Based on SingleRIM
  1. Obtain the GERAN information from the RIM procedure.
    Enable a UE to camp on an E-UTRAN cell and originate a voice call. After receiving a CSFB indication from the MME, the eNodeB sends a RIM request message to obtain the system information.
  2. Perform flash CSFB to GERAN.
    If the call continues and the RRC Connection Release message traced on the Uu interface carries the information about the neighboring GERAN cell, flash CSFB to GERAN has been activated successfully.
    This procedure is the same as that for the RIM procedure in Multiple Report mode.
Counter Observation
Verify that this feature has taken effect by observing the L.flashCSFB.E2G counter.

7.4.3.5 Deactivation

Using the CME to Perform Batch Configuration
Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that for feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 7-20.
Table 7-20 Parameters for flash CSFB to GERAN
MO
Sheet in the Summary Data File
Parameter Group
Setting Notes
ENodeBAlgoSwitch
ENodeBAlgoSwitch
HoAlgoSwitch
GeranFlashCsfbSwitch:Off
Using the CME to Perform Single Configuration
On the CME, set parameters according to Table 7-20. For detailed instructions, see Using the CME to Perform Single Configuration for feature activation.
Using MML Commands
Run the MOD ENODEBALGOSWITCH command with the GeranFlashCsfbSwitch(GeranFlashCsfbSwitch) check box cleared under the HoAlgoSwitch parameter.

7.4.3.6 MML Command Examples

NOTE:
The parameters in this section are for reference only. Configure the parameters depending on network requirements.
Activating Flash CSFB to GERAN
The flash CSFB to GERAN feature requires the CSFB to GERAN feature. For details about the basic configuration, see Activating CSFB to GERAN. For details about the configuration related to flash CSFB to GERAN, refer to the following commands.
//To turn on the algorithm switch and handover switch, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=GeranFlashCsfbSwitch-1&CsfbAdaptiveBlindHoSwitch-1,RimSwitch=GERAN_RIM_SWITCH-1;
NOTE:
Select the GeranFlashCsfbSwitch(GeranFlashCsfbSwitch) check box.
To enable CSFB based on the RIM procedure in Multiple Report mode, select the GERAN_RIM_SWITCH(GERAN RIM Switch) check box; to enable CSFB based on the RIM procedure in Single Report mode, keep the GERAN_RIM_SWITCH(GERAN RIM Switch) check box cleared.
To enable CSFB based on the adaptive blind handover, select the CsfbAdaptiveBlindHoSwitch(CsfbAdaptiveBlindHoSwitch) check box.
//To set the A1 threshold for adaptive blind handovers, run the following command:
MOD CSFALLBACKHO: LocalCellId=0, BlindHoA1ThdRsrp=-95;
//To configure the CSFB priority, run the following command:
MOD CSFALLBACKBLINDHOCFG: CnOperatorId=0, InterRatHighestPri=GERAN, InterRatSecondPri=UTRAN, UtranLcsCap=ON;
//To set the maximum number of GERAN cells, run the following command:
MOD INTERRATHOCOMM: CellInfoMaxUtranCellNum=16;
Deactivating Flash CSFB to GERAN
//To deactivate flash CSFB to GERAN, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=GeranFlashCsfbSwitch-0;

7.5 TDLOFD-001068 CS Fallback with LAI to UTRAN

7.5.1 When to Use CSFB with LAI to UTRAN

Use TDLOFD-001068 CS Fallback with LAI to UTRAN when both of the following conditions are met:
  • TDLOFD-001033 CS Fallback to UTRAN has been enabled.
  • The E-UTRAN cell has neighboring UTRAN cells that belong to different PLMNs and supports inter-PLMN handovers, or the E-UTRAN cell has neighboring cells that have different LACs.
Use TDLOFD-001068 CS Fallback with LAI to UTRAN also when both of the following conditions are met:
  • TDLOFD-001033 CS Fallback to UTRAN and TDLOFD-001034 CS Fallback to GERAN have been enabled.
  • The neighboring UTRAN and GERAN cells have different LAIs.

7.5.2 Required Information

  1. Collect the operating frequencies, coverage areas, and configurations of the E-UTRAN and UTRAN cells.
  2. Collect the versions and configurations of the NEs in the E-UTRAN, UTRAN, and core networks, and ensure that they all support CSFB and MMEs support delivering LAI delivery. Table 7-21 describes the requirements of CSFB with LAI to UTRAN for the core networks.
  3. Collect the following information about the UEs supporting UMTS and LTE on the live network:
    • Supported frequency bands
    • Whether the UEs support redirection from E-UTRAN to UTRAN
    • Whether the UEs support PS handovers from E-UTRAN to UTRAN
    • Whether the UEs support UTRAN measurements
    This information is used to configure neighboring UTRAN cells and to determine whether to perform CSFB based on handover or redirection. For details, see Mobility Management in Connected Mode Feature Parameter Description.
Table 7-21 Requirements of CSFB with LAI to UTRAN for the core networks
NE
Description
MME
Supports:
  • SGs interface to the MSC
  • VLR and LAI selection based on the TAI of the serving cell
  • MSC-initiated paging
  • PLMN selection and reselection
  • Combined EPS/IMSI attach, combined EPS/IMSI detach, and combined TAU/LAU
  • Routing of CS signaling messages
  • SMS over SGs
  • LAI delivery
MSC
Supports:
  • Combined EPS/IMSI attach
  • SMS over SGs
  • Paging message forwarding over the SGs interface
SGSN
Does not activate ISR during the combined RAU/LAU procedure initiated by the UE.

7.5.3 Deployment

This section describes configuration, activation, and observation of CSFB with LAI to UTRAN.

7.5.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, check with the vendor whether the equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-22.
Table 7-22 License information for CSFB with LAI to UTRAN
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001033
CS Fallback to UTRAN
CS Fallback to UTRAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001068
CS Fallback with LAI to UTRAN
CS Fallback with LAI to UTRAN(TDD)
eNodeB
per RRC Connected User

7.5.3.2 Data Preparation

Data preparation for CSFB with LAI to UTRAN is similar to that for CSFB to UTRAN described in 7.1.3.2 Data Preparation.

7.5.3.3 Activation

CSFB with LAI to UTRAN is automatically activated when two conditions are met:
  • The license for this feature has been activated.
  • CSFB to UTRAN has been activated.
For details about how to activate CSFB to UTRAN, see 7.1.3.3 Activation.

7.5.3.4 Activation Observation

Signaling Observation
  1. Configure two neighboring UTRAN cells with different LAIs for an E-UTRAN cell, and enable the MME to include only one of the two LAIs in the indications that will be delivered to the eNodeB.
  2. Ensure that the signal strengths of the two UTRAN cells both reach the threshold for event B1. You can query the threshold by running the LST INTERRATHOUTRANGROUP command.
  3. Enable a UE to camp on the E-UTRAN cell and originate a voice call so that the UE falls back to the UTRAN cell with the specified LAI and completes the call.
  4. Enable a UE to camp on the E-UTRAN cell and receive a voice call so that the UE falls back to the UTRAN cell with the specified LAI and completes the call.
  5. The Initial Context Setup Request message or UE Context Modification Request message carries the LAI that the MME delivers to the eNodeB.
You can observe the signaling procedure for CSFB with LAI to UTRAN, which is similar to that for CSFB to UTRAN described in 7.1.3.4 Activation Observation.
Counter Observation
Verify that CSFB with LAI to UTRAN has taken effect by observing the L.CSFB.E2W counter.

7.5.3.5 Deactivation

CSFB with LAI to UTRAN is automatically deactivated when its license or CSFB to UTRAN is deactivated. For details about how to deactivate CSFB to UTRAN, see 7.1.3.5 Deactivation.

7.5.3.6 MML Command Examples

The MML configuration for CSFB with LAI to UTRAN is similar to that for CSFB to UTRAN described in 7.1.3.6 MML Command Examples.

7.6 TDLOFD-001069 CS Fallback with LAI to GERAN

7.6.1 When to Use CSFB with LAI to GERAN

Use TDLOFD-001069 CS Fallback with LAI to GERAN when both of the following conditions are met:
  • TDLOFD-001034 CS Fallback to GERAN has been enabled.
  • The E-UTRAN cell has neighboring GERAN cells that belong to different PLMNs and supports inter-PLMN handovers, or the E-UTRAN cell has neighboring GERAN cells that have different LACs.
Use TDLOFD-001069 CS Fallback with LAI to GERAN also when both of the following conditions are met:
  • TDLOFD-001033 CS Fallback to UTRAN and TDLOFD-001034 CS Fallback to GERAN have been enabled.
  • The neighboring UTRAN and GERAN cells have different LAIs.

7.6.2 Required Information

  1. Collect the operating frequencies, coverage areas, and configurations of the E-UTRAN and GERAN cells.
  2. Collect the versions and configurations of the NEs in the E-UTRAN, GERAN, and core networks, and ensure that they all support CSFB and the MME supports LAI delivery. Table 7-23 describes the requirements of CSFB with LAI to GERAN for the core networks.
  3. Collect the following information about the UEs supporting GSM and LTE on the live network: Supported frequency bands Whether the UEs support redirection from E-UTRAN to GERAN Whether the UEs support PS handovers from E-UTRAN to GERAN Whether the UEs support GERAN measurements This information is used to configure neighboring GERAN cells and to determine whether to perform CSFB based on handover or redirection. For details, see Mobility Management in Connected Mode Feature Parameter Description.
Table 7-23 Requirements of CSFB with LAI to GERAN for the core networks
NE
Description
MME
Supports:
  • SGs interface to the MSC
  • VLR and LAI selection based on the TAI of the serving cell
  • MSC-initiated paging
  • PLMN selection and reselection
  • Combined EPS/IMSI attach, combined EPS/IMSI detach, and combined TAU/LAU
  • Routing of CS signaling messages
  • SMS over SGs
  • LAI delivery
MSC
Supports:
  • Combined EPS/IMSI attach
  • SMS over SGs
  • Paging message forwarding over the SGs interface
SGSN
Does not activate ISR during the combined RAU/LAU procedure initiated by the UE.

7.6.3 Deployment

This section describes configuration, activation, and observation of CSFB with LAI to GERAN.

7.6.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, ensure that the core network equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-24.
Table 7-24 License information for CSFB with LAI to GERAN
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001034
CS Fallback to GERAN
CS Fallback to GERAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001069
CS Fallback with LAI to GERAN
CS Fallback with LAI to GERAN(TDD)
eNodeB
per RRC Connected User

7.6.3.2 Data Preparation

Data preparation for CSFB with LAI to GERAN is similar to that for CSFB to GERAN described in 7.2.3.2 Data Preparation.

7.6.3.3 Activation

CSFB with LAI to GERAN is automatically activated when two conditions are met: The license for this feature has been activated. CSFB to GERAN has been activated. For details about how to activate CSFB to GERAN, see 7.2.3.3 Activation.

7.6.3.4 Activation Observation

  1. Configure two neighboring GERAN cells with different LAIs for an E-UTRAN cell, and enable the MME to include only one of the two LAIs in the indications that will be delivered to the eNodeB.
  2. Ensure that the signal strengths of both the two GERAN cells reach the threshold for event B1. You can query the threshold by running the LST INTERRATHOGERANGROUP command.
  3. Enable a UE to camp on the E-UTRAN cell and originate a voice call. The UE falls back to a GERAN cell with the specified LAI for voice services.
  4. Enable a UE to camp on the E-UTRAN cell and receive a voice call. The UE falls back to the GERAN cell with the specified LAI for voice services.
Signaling Observation
  1. The Initial Context Setup Request message or UE Context Modification Request message carries the LAI that the MME delivers to the eNodeB.
  2. The signaling procedure for CSFB with LAI to GERAN is similar to that for CSFB to GERAN described in 7.2.3.4 Activation Observation.
Counter Observation
Verify that CSFB with LAI to GERAN has taken effect by observing the L.CSFB.E2G counter.

7.6.3.5 Deactivation

CSFB with LAI to GERAN is automatically deactivated when its license or CSFB to GERAN is deactivated. For details about how to deactivate CSFB to GERAN, see 7.2.3.5 Deactivation.

7.6.3.6 MML Command Examples

The MML configuration for CSFB with LAI to GERAN is similar to that for CSFB to GERAN described in 7.2.3.6 MML Command Examples.

7.7 TDLOFD-001088 CS Fallback Steering to UTRAN

7.7.1 When to Use CSFB Steering to UTRAN

When TDLOFD-001033 CS Fallback to UTRAN has been activated, this feature can be activated to improve network efficiency and user experience if operators have different requirements for CSFB RAT, frequencies of CSFB to UTRAN, or handovers of voice services and combined voice and data services. If operators have UTRAN and GERAN where CSFB can be performed, TDLOFD-001089 CS Fallback Steering to GERAN can also be activated after activation of this feature so that UTRAN and GERAN efficiency is improved.

7.7.2 Required Information

  1. Verify that TDLOFD-001033 CS Fallback to UTRAN has been deployed successfully.
  2. Collect the following information about the UEs supporting UMTS and LTE on the live network:
    • Supported frequency bands
    • Whether the UEs support redirection from E-UTRAN to UTRAN
    • Whether the UEs support PS handovers from E-UTRAN to UTRAN
    • Whether the UEs support UTRAN measurements
    This information is used to configure neighboring UTRAN cells and to determine whether to perform CSFB based on handover or redirection. For details, see Mobility Management in Connected Mode Feature Parameter Description.
  3. Collect information about UTRAN frequencies. It is recommended that this information be consistent between UTRAN and E-UTRAN. For example, if UTRAN F1 is used for voice first services, E-UTRAN F1 is also used for voice first services.
  4. If both TDLOFD-001089 CS Fallback Steering to GERAN and TDLOFD-001088 CS Fallback Steering to UTRAN are deployed, the UTRAN and GERAN frequency policies must be considered together.

7.7.3 Deployment

This section describes configuration, activation, and observation of TDLOFD-001088 CS Fallback Steering to UTRAN.

7.7.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, check with the vendor whether the equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-25.
Table 7-25 License information for CSFB steering to UTRAN
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001033
CS Fallback to UTRAN
CS Fallback to UTRAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001088
CS Fallback Steering to UTRAN
CS Fallback Steering to UTRAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001078
E-UTRAN to UTRAN CS/PS Steering
E-UTRAN to UTRAN CS/PS steering(TDD)
eNodeB
per RRC Connected User

7.7.3.2 Data Preparation

This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Collect scenario-specific data when necessary for a specific feature deployment scenario. You need to collect both required data and scenario-specific data based on requirements.
There are three types of data sources:
  • Network plan (negotiation not required): parameter values planned and set by the operator
  • Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment
  • User-defined: parameter values set by users
Required Data
The data preparation is similar to that described in Required Data.
Scenario-specific Data
The following table describes the parameters that must be set in the ENodeBAlgoSwitch MO to set the handover mode and handover algorithm switches for CSFB steering to UTRAN.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Algo switch
Network plan (negotiation not required)
Select the UtranCsfbSteeringSwitch(UtranCsfbSteeringSwitch) check box.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the inter-RAT priorities for UEs in connected mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CN Operator ID
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the ID of the operator whose inter-RAT blind-handover priorities are to be set.
Highest priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in blind handovers for CSFB. For CSFB to UTRAN, set this parameter to UTRAN.
Second priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the medium-priority system to be considered in blind handovers for CSFB. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
UTRAN LCS capability
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the LCS capability of the UTRAN.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the inter-RAT priorities for UEs in idle mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB Highest priority InterRat for Idle UE
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in CSFB for UEs in idle mode. For CSFB to UTRAN, set this parameter to UTRAN.
CSFB Second priority InterRat for Idle UE
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the high-priority system to be considered in CSFB for UEs in idle mode. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
The following table describes the parameters that must be set in the UTRANNFREQ MO to set the UTRAN priorities for UEs in idle mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CS service priority
Network plan (negotiation not required)
Set this parameter based on the network plan. Priority_0: Indicates that CS services are prohibited. Priority_16 and Priority_1 indicate the highest and lowest priorities, respectively. It is recommended UTRAN frequency priority be set as the highest one.
The following table describes the parameters that must be set in the UTRANNFREQ MO to set the UTRAN priorities for UEs in connected mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CS and PS mixed priority
Network plan (negotiation not required)
Set this parameter based on the network plan. Priority_0: Indicates that CS services are prohibited. Priority_16 and Priority_1 indicate the highest and lowest priorities, respectively. It is recommended UTRAN frequency priority be set as the highest one.
The following table describes the parameters that must be set in the CSFallBackPolicyCfg MO to set the handover mode for UEs in connected mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB handover policy Configuration
Network plan (negotiation not required)
Set this parameter based on the network plan. The default configurations include redirection, CCO_HO, and PS_HO. It is recommended that handover modes be selected based on capabilities of UEs and networks.
The following table describes the parameters that must be set in the CSFallBackPolicyCfg MO to set the handover mode for UEs in idle mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB handover policy Configuration for idle ue
Network plan (negotiation not required)
Set this parameter based on the network plan. The default configurations include redirection, CCO_HO, and PS_HO. It is recommended that handover modes be selected based on capabilities of UEs and networks.

7.7.3.3 Activation

Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs
Enter the values of the parameters listed in Table 7-26 in a summary data file, which also contains other data for the new eNodeBs to be deployed. Then, import the summary data file into the CME for batch configuration. For detailed instructions, see section "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB.
The summary data file may be a scenario-specific file provided by the CME or a customized file, depending on the following conditions:
  • The MOs in Table 7-26 are contained in a scenario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save the file.
  • Some MOs in Table 7-26 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters.
Table 7-26 Parameters for CSFB steering to UTRAN
MO
Sheet in the Summary Data File
Parameter Group
Remarks
ENodeBAlgoSwitch
ENodeBAlgoSwitch
Handover Algo switch
User-defined template
CSFallBackBlindHoCfg
CSFallBackBlindHoCfg
CN Operator ID, Highest priority InterRat, Second priority InterRat, GERAN LCS capability, CSFB Highest priority InterRat for Idle UE, and CSFB Second priority InterRat for Idle UE
User-defined template
CSFALLBACKPOLICYCFG
CSFALLBACKPOLICYCFG
CSFB handover policy Configuration and CSFB handover policy Configuration for idle ue
User-defined template
UtranNFreq
UtranNFreq
Local cell ID, Downlink UARFCN, CS service priority, and CS and PS mixed priority
User-defined template
Using the CME to Perform Batch Configuration for Existing eNodeBs
Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure is as follows:
  1. Choose CME > Advanced > Customize Summary Data File from the main menu of an M2000 client, or choose Advanced > Customize Summary Data File from the main menu of a CME client, to customize a summary data file for batch reconfiguration.
    NOTE:
    For context-sensitive help on a current task in the client, press F1.
  2. Choose CME > LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the CME client, to export the eNodeB data stored on the CME into the customized summary data file.
  3. In the summary data file, set the parameters in the MOs listed in "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs" and close the file.
  4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application> Import Data > Import Base Station Bulk Configuration Data from the main menu of the CME client, to import the summary data file into the CME.
  5. Choose CME > Planned Area > Export Incremental Scripts from the main menu of the M2000 client, or choose Area Management > Planned Area > Export Incremental Scripts from the main menu of the CME client, to export and activate the incremental scripts.
Using the CME to Perform Single Configuration
On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows:
  1. In the planned data area, click Base Station in the upper left corner of the configuration window.
  2. In area 1 shown in Figure 7-8, select the eNodeB to which the MOs belong.
    Figure 7-8 MO search and configuration window
  3. On the Search tab page in area 2, enter an MO name, for example, CELL.
  4. In area 3, double-click the MO in the Object Name column. All parameters in this MO are displayed in area 4.
  5. Set the parameters in area 4 or 5.
  6. Choose CME > Planned Area > Export Incremental Scripts (M2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.
Using MML Commands
  1. Configure TDLOFD-001033 CS Fallback to UTRAN. For details, see Using MML Commands.
  2. Run the MOD ENODEBALGOSWITCH command to configure the handover algorithm switch for CSFB steering to UTRAN.
  3. Run the MOD CSFALLBACKBLINDHOCFG command to configure the CSFB inter-RAT priorities for UEs in connected and idle modes.
  4. Run the MOD UTRANNFREQ command to configure the CS service priority and CS and PS mixed priority
  5. Run the MOD CSFallBackPolicyCfg to configure the CSFB handover policy configuration and CSFB handover policy configuration for idle UE.

7.7.3.4 Activation Observation

  1. Ensure that UEs support CSFB redirection and handover.
  2. Set the CSFB handover policy Configuration for idle ue and CSFB handover policy Configuration parameters to REDIRECTION and PS_HO, respectively.
  3. Enable the UE to camp on the LTE cell and perform CSFB for two mobile-originated calls by UE in idle and connected modes, respectively.
  4. The total times of CSFB, redirection-based CSFB, and handover-based CSFB increase by two, one, and one, respectively.
If TDLOFD-001089 CS Fallback Steering to GERAN is enabled, the verification is as follows:
  1. Ensure that UEs support CSFB to GERAN and CSFB to UTRAN.
  2. Set the IdleCsfbHighestPri and InterRatHighestPri parameter to GERAN and UTRAN, respectively.
  3. Perform CSFB for two mobile-originated calls by the UE in idle and connected modes, respectively.
  4. The UE in idle and connected modes falls back to the GERAN network in redirection and PS handover modes, respectively. The total times of CSFB, redirection-based CSFB, handover-based CSFB, CSFB to UTRAN, and CSFB to GERAN increase by two, one, one, one, and one, respectively.
If TDLOFD-001078 E-UTRAN to UTRAN CS/PS Steering is enabled, the verification is as follows:
  1. Set CSFB priorities for UEs in connected and idle modes to UTRAN.
  2. Configure two UTRAN neighboring frequencies represented by F1 and F2. The CS service priority on F1 is higher than that on F2, and the CS and PS mixed priority on F1 is lower than that on F2.
  3. Perform CSFB for two mobile-originated calls by the UE in idle and connected modes, respectively.
  4. The UE in idle mode and connected mode falls back to the network on F1 and F2, respectively.
Signaling Observation
The procedures of CSFB steering to UTRAN and CSFB to UTRAN are the same. For details, see 7.1.3.4 Activation Observation.
Counter Observation
Verify that the CSFB steering to UTRAN has taken effect by observing the L.CSFB.PrepSucc, L.CSFB.PrepSucc.Idle, L.CSFB.E2W, L.CSFB.E2W.Idle, and L.CSFB.E2G counters.
Verify that this feature takes effect by observing the LIRATHO.E2W.CSFB.ExecAttOut, LIRATHO.E2W.CSFB.ExecSuccOut, LIRATHO.E2W.CSFB.PrepAttOut, and L.RRCRedirection.E2W.CSFB counters.

7.7.3.5 Deactivation

Using the CME to Perform Batch Configuration
Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that for feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 7-27.
Table 7-27 Parameters for CSFB steering to UTRAN
MO
Sheet in the Summary Data File
Parameter Group
Setting Notes
ENodeBAlgoSwitch
ENodeBAlgoSwitch
HoAlgoSwitch
UtranCsfbSteeringSwitch:Off
Using the CME to Perform Single Configuration
On the CME, set parameters according to Table 7-27. For detailed instructions, see Using the CME to Perform Single Configuration for feature activation.
Using MML Commands
Run the MOD ENODEBALGOSWITCH command with the UtranCsfbSteeringSwitch(UtranCsfbSteeringSwitch) check box cleared under the HoAlgoSwitch parameter.

7.7.3.6 MML Command Examples

NOTE:
The parameters in this section are for reference only. Configure the parameters depending on network requirements.
Activating CSFB Steering to UTRAN
The CSFB steering to UTRAN feature requires the CSFB to UTRAN feature. For details about MML commands, see 7.1.3.6 MML Command Examples.
For details about MML commands related to CSFB steering to UTRAN, see the following examples. Set the parameters based on the network plan.
//To turn on the handover algorithm switch, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=UtranCsfbSteeringSwitch-1;
//To set the CS service priority and CS and PS mixed priority for the UTRAN neighboring frequency, run the following command:
MOD UTRANNFREQ: LocalCellId=0, UtranDlArfcn=10700, CsPriority=Priority_16, CsPsMixedPriority=Priority_16;
//To enable a UE to preferentially fall back to the UTRAN, run the following command:
MOD CSFALLBACKBLINDHOCFG: CnOperatorId=0, InterRatHighestPri=UTRAN, InterRatSecondPri=GERAN, InterRatLowestPri=CDMA2000, UtranLcsCap=ON, IdleCsfbHighestPri=UTRAN, IdleCsfbSecondPri=GERAN, IdleCsfbLowestPri=CDMA2000;
//To set the CSFB handover policy configuration, run the following command:
MOD CSFALLBACKPOLICYCFG: CsfbHoPolicyCfg=REDIRECTION-0&PS_HO-1, IdleModeCsfbHoPolicyCfg=REDIRECTION-1&PS_HO-0;
Deactivating CSFB Steering to UTRAN
//To deactivate CSFB steering to UTRAN, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=UtranCsfbSteeringSwitch-0;

7.8 TDLOFD-001089 CS Fallback Steering to GERAN

7.8.1 When to Use CSFB Steering to GERAN

When TDLOFD-001034 CS Fallback to GERAN has been activated, if operators have different requirements for CSFB system, or handovers of voice services and voice and data services, this feature can be activated to improve network efficiency and user experience. If operators have UTRAN and GERAN where handovers can be performed, TDLOFD-001088 CS Fallback Steering to UTRAN can also be activated after activation of this feature so that UTRAN and GERAN efficiency is improved.

7.8.2 Required Information

  1. Verify that TDLOFD-001034 CS Fallback to GERAN has been deployed successfully.
  2. Collect the following information about the UEs supporting GSM and LTE on the live network:
    • Supported frequency bands
    • Whether the UEs support redirection from E-UTRAN to GERAN
    • Whether the UEs support PS-handover- or CCO-based CSFB from E-UTRAN to GERAN
    • Whether the UEs support GERAN measurements
    This information is used to configure neighboring GERAN cells and to determine whether to perform CSFB based on handover, redirection, or CCO. For details, see Mobility Management in Connected Mode Feature Parameter Description.
  3. Obtain the frequency bands and frequencies of the GERAN on the live network. Ensure that the frequency information between the GERAN and E-UTRAN is consistent.
  4. If both TDLOFD-001089 CS Fallback Steering to GERAN and TDLOFD-001088 CS Fallback Steering to UTRAN are required, consider both UTRAN and GERAN frequencies when determining frequency policies.

7.8.3 Deployment

This section describes configuration, activation, and observation of TDLOFD-001034 CS Fallback to GERAN.

7.8.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, ensure that the core network equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-28.
Table 7-28 License information for CSFB steering to GERAN
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001034
CS Fallback to GERAN
CS Fallback to GERAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001089
CS Fallback Steering to GERAN
CS Fallback Steering to GERAN(TDD)
eNodeB
per RRC Connected User

7.8.3.2 Data Preparation

This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Collect scenario-specific data when necessary for a specific feature deployment scenario. You need to collect both required data and scenario-specific data based on requirements.
There are three types of data sources:
  • Network plan (negotiation not required): parameter values planned and set by the operator
  • Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment
  • User-defined: parameter values set by users
Required Data
Before configuring CSFB to GERAN, collect the data related to neighbor relationships with GERAN cells. This section provides only the information about MOs related to neighboring GERAN cells. For details about how to collect data for the parameters in these MOs, see Mobility Management in Connected Mode Feature Parameter Description. Collect data for the parameters in the following MOs:
  1. GeranNfreqGroup: used to configure neighboring GERAN frequencies.
  2. GeranNfreqGroupArfcn: used to configure neighboring GERAN BCCH frequencies.
  3. GeranExternalCell: used to configure external GERAN cells. If PS handover is used, the Rac parameter must be configured.
  4. GeranExternalCellPlmn: used to configure additional PLMN IDs for a shared external GERAN cell. This MO is required only if the NodeB providing the external GERAN cell works in RAN sharing with common carriers mode and multiple operators share the external GERAN cell for more than one hour.
  5. GeranNcell: used to configure neighbor relationships with GERAN cells. If a neighboring GERAN cell supports blind handovers according to the network plan, the blind-handover priority of the cell must be specified by the BlindHoPriority parameter.
Scenario-specific Data
The following table describes the parameters that must be set in the ENodeBAlgoSwitch MO to set the handover mode and handover algorithm switches for CSFB to GERAN.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Mode switch
Network plan (negotiation not required)
Set this parameter based on the network plan.
To activate PS handovers, select the GeranPsHoSwitch(GeranPsHoSwitch) check box. To activate handovers based on CCO, select the GeranCcoSwitch(GeranCcoSwitch) check box. To activate handovers based on NACC, select the GeranNaccSwitch(GeranNaccSwitch) check box. If none of these check boxes is selected, redirection will be performed for CSFB to GERAN.
To activate blind handovers, select the BlindHoSwitch(BlindHoSwitch) check box. A blind handover to an inter-RAT cell can be performed only if the blind handover priority is specified for the inter-RAT cell. Compared with measurement-based handovers, blind handovers have shorter access delays but a lower handover success rate.
Handover Algo switch
Network plan (negotiation not required)
To activate CSFB to GERAN, select the GeranCsfbSwitch(GeranCsfbSwitch) check box. To activate flash CSFB to GERAN, select the GeranFlashCsfbSwitch(GeranFlashCsfbSwitch) check box.
To activate CSFB steering to GERAN, select the GeranCsfbSteeringSwitch(GeranCsfbSteeringSwitch) check box.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the inter-RAT priorities for UEs in connected mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CN Operator ID
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the ID of the operator whose inter-RAT blind-handover priorities are to be set.
Highest priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in blind handovers for CSFB. For CSFB steering to GERAN, set this parameter to GERAN.
Second priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the medium-priority system to be considered in blind handovers for CSFB. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
GERAN LCS capability
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the LCS capability of the GERAN.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the inter-RAT priorities for UEs in idle mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB Highest priority InterRat for Idle UE
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in CSFB for UEs in idle mode. For CSFB fallback to UTRAN, set this parameter to UTRAN.
CSFB Second priority InterRat for Idle UE
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the medium-priority system to be considered in CSFB for UEs in idle mode. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
The following table describes the parameters that must be set in the CSFallBackPolicyCfg MO to set the handover mode for UEs in connected mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB handover policy Configuration
Network plan (negotiation not required)
Set this parameter based on the network plan. The default configurations include redirection, CCO_HO, and PS_HO. It is recommended that handover modes be selected based on capabilities of UEs and networks.
The following table describes the parameters that must be set in the CSFallBackPolicyCfg MO to set the handover mode for UEs in idle mode.
Parameter Name
Parameter ID
Data Source
Setting Notes
CSFB handover policy Configuration for idle ue
Network plan (negotiation not required)
Set this parameter based on the network plan. The default configurations include redirection, CCO_HO, and PS_HO. It is recommended that handover modes be selected based on capabilities of UEs and networks.

7.8.3.3 Activation

Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs
Enter the values of the parameters listed in Table 7-29 in a summary data file, which also contains other data for the new eNodeBs to be deployed. Then, import the summary data file into the CME for batch configuration. For detailed instructions, see section "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB.
The summary data file may be a scenario-specific file provided by the CME or a customized file, depending on the following conditions:
  • The MOs in Table 7-29 are contained in a scenario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save the file.
  • Some MOs in Table 7-29 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters.
Table 7-29 Parameters for CS fallback steering to GERAN
MO
Sheet in the Summary Data File
Parameter Group
Remarks
CSFallBackBlindHoCfg
CSFallBackBlindHoCfg
CN Operator ID, Highest priority InterRat, Second priority InterRat, UTRAN LCS capability, CSFB Highest priority InterRat for Idle UE, and CSFB Second priority InterRat for Idle UE
User-defined template
CSFALLBACKPOLICYCFG
CSFALLBACKPOLICYCFG
CSFB handover policy Configuration and CSFB handover policy Configuration for idle ue
User-defined template
CSFallBackHo
ENodeBAlgoSwitch
Handover Algo switch
User-defined template
Using the CME to Perform Batch Configuration for Existing eNodeBs
Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure is as follows:
  1. Choose CME > Advanced > Customize Summary Data File from the main menu of an M2000 client, or choose Advanced > Customize Summary Data File from the main menu of a CME client, to customize a summary data file for batch reconfiguration.
    NOTE:
    For context-sensitive help on a current task in the client, press F1.
  2. Choose CME > LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the CME client, to export the eNodeB data stored on the CME into the customized summary data file.
  3. In the summary data file, set the parameters in the MOs listed in "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs" and close the file.
  4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application> Import Data > Import Base Station Bulk Configuration Data from the main menu of the CME client, to import the summary data file into the CME.
  5. Choose CME > Planned Area > Export Incremental Scripts from the main menu of the M2000 client, or choose Area Management > Planned Area > Export Incremental Scripts from the main menu of the CME client, to export and activate the incremental scripts.
Using the CME to Perform Single Configuration
On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows:
  1. In the planned data area, click Base Station in the upper left corner of the configuration window.
  2. In area 1 shown in Figure 7-9, select the eNodeB to which the MOs belong.
    Figure 7-9 MO search and configuration window
  3. On the Search tab page in area 2, enter an MO name, for example, CELL.
  4. In area 3, double-click the MO in the Object Name column. All parameters in this MO are displayed in area 4.
  5. Set the parameters in area 4 or 5.
  6. Choose CME > Planned Area > Export Incremental Scripts (M2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.
Using MML Commands
  1. Configure TDLOFD-001034 CS Fallback to GERAN. For details, see 7.2.3.3 Activation.
  2. Run the MOD ENODEBALGOSWITCH command to configure Handover Algo switch for CS Fallback Steering to GERAN.
  3. Run the MOD CSFALLBACKBLINDHOCFG command to configure MOs related to CSFB inter-RAT priority for UEs in connected or idle mode.
  4. Run the MODCSFallBackPolicyCfg to configure the CSFB handover policy Configuration and CSFB handover policy Configuration for idle ue parameters.

7.8.3.4 Activation Observation

  1. Ensure that UEs support redirection-based CSFB and handover-based CSFB.
  2. Set the CSFB Highest priority InterRat for Idle and Highest priority InterRat parameters to GERAN.
  3. Set the CSFB handover policy Configuration for idle ue and CSFB handover policy Configuration parameters to REDIRECTION and PS_HO, respectively.
  4. Enable the UE to camp on the LTE cell and perform CSFB for two mobile-originated calls by the UE in idle and connected modes, respectively.
  5. If the CSFB succeeds, the UE in idle and connected modes falls back to the GERAN network in redirection and PS handover modes, respectively.
If TDLOFD-001088 CS Fallback Steering to UTRAN is also enabled, the verification is as follows:
  1. Ensure that UEs support CSFB to GERAN and CSFB to UTRAN.
  2. Set the CSFB Highest priority InterRat for Idle UE and Highest priority InterRat parameters to GERAN and UTRAN, respectively.
  3. Set the CSFB handover policy Configuration for idle ue and CSFB handover policy Configuration parameters to REDIRECTION and PS_HO, respectively.
  4. Perform CSFB for two mobile-originated calls by the UE in idle and connected modes, respectively.
  5. The UE in idle and connected modes falls back to the GERAN network in redirection and PS handover modes, respectively. The total occurrences of CSFB increase by 2, and the occurrences of redirection-based CSFB, handover-based CSFB, CSFB to UTRAN, and CSFB to GERAN each increases by 1.
Signaling Observation
The procedures of CSFB steering to UTRAN and CSFB to UTRAN are the same. For details, see 7.1.3.4 Activation Observation.
Counter Observation
For details about activation based on RAT strategy, see Counter Observation.
Verify that this feature has taken effect by observing the CSFB-triggered RRC redirection times from E-UTRAN to GERAN, and times of handover implementation, handover success rates, and preparation attempts from E-UTRAN to GERAN.

7.8.3.5 Deactivation

Using the CME to Perform Batch Configuration
Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that for feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 7-30.
Table 7-30 Parameters for CSFB steering to GERAN
MO
Sheet in the Summary Data File
Parameter Group
Setting Notes
ENodeBAlgoSwitch
ENodeBAlgoSwitch
HoAlgoSwitch
GeranCsfbSteeringSwitch:Off
Using the CME to Perform Single Configuration
On the CME, set parameters according to Table 7-30. For detailed instructions, see Using the CME to Perform Single Configuration for feature activation.
Using MML Commands
Run the MOD ENODEBALGOSWITCH command with the GeranCsfbSteeringSwitch(GeranCsfbSteeringSwitch) check box under the HoAlgoSwitch parameter cleared.

7.8.3.6 MML Command Examples

NOTE:
The parameters in this section are for reference only. Configure the parameters depending on network requirements.
Activating CS Fallback Steering to GERAN
Activate CSFB to GERAN before you activate CSFB steering to GERAN. For details about how to activate CSFB to GERAN, see 7.2.3.6 MML Command Examples.
The following lists the MML command examples related to CSFB steering to GERAN. Set the parameters according to the network plan.
//To turn on the handover algorithm switch for CSFB steering to GERAN, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=GeranCsfbSteeringSwitch-1;
//To enable a UE to preferentially fall back to the GERAN, run the following command:
MOD CSFALLBACKBLINDHOCFG: CnOperatorId=0, InterRatHighestPri=GERAN, InterRatSecondPri=UTRAN, InterRatLowestPri=CDMA2000, GeranLcsCap=OFF, IdleCsfbHighestPri=GERAN, IdleCsfbSecondPri=UTRAN, IdleCsfbLowestPri=CDMA2000;
//To set the CSFB handover policy Configuration parameter, run the following command:
MOD CSFALLBACKPOLICYCFG: CsfbHoPolicyCfg=REDIRECTION-0&CCO_HO-1&PS_HO-1, IdleModeCsfbHoPolicyCfg=REDIRECTION-1&CCO_HO-0&PS_HO-0;
Deactivating CS Fallback Steering to GERAN
To deactivate CSFB steering to GERAN, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=GeranCsfbSteeringSwitch-0;

7.9 TDLOFD-001078 E-UTRAN to UTRAN CS/PS Steering

7.9.1 When to Use E-UTRAN to UTRAN CS/PS Steering

It is recommended that TDLOFD-001078 E-UTRAN to UTRAN CS/PS Steering be enabled when the following conditions are both met: TDLOFD-001033 CS Fallback to UTRAN and TDLOFD-001019 PS Inter-RAT Mobility between E-UTRAN and UTRAN have been activated, and operators have separate UTRAN networks for CSFB of PS and CS services, respectively.

7.9.2 Required Information

  1. Verify that TDLOFD-001033 CS Fallback to UTRAN has been deployed successfully.
  2. Verify that TDLOFD-001019 PS Inter-RAT Mobility between E-UTRAN and UTRAN has been deployed successfully.
  3. Collect the following information about the UEs supporting UMTS and LTE on the live network:
    • Supported frequency bands Whether the UEs support redirection from E-UTRAN to UTRAN
    • Whether the UEs support PS handovers from E-UTRAN to UTRAN
    • Whether the UEs support UTRAN measurements
    This information is used to configure neighboring UTRAN cells and to determine whether to perform CSFB based on handover or redirection. For details, see Mobility Management in Connected Mode Feature Parameter Description.
  4. Obtain information about UTRAN frequencies and frequency policies. For example, F1 and F2 for the UTRAN are preferentially used for voice first services and data first services, respectively.

7.9.3 Deployment

This section describes configuration, activation, and observation of TDLOFD-001078 E-UTRAN to UTRAN CS/PS Steering.

7.9.3.1 Requirements

Operating Environment
This feature requires support from the core network equipment working with the eNodeB. If Huawei core network equipment is used, the version must be PS10.0. If the core network equipment is provided by another vendor, check with the vendor whether the equipment supports this feature.
License
The operator has purchased and activated the license for the feature listed in Table 7-31.
Table 7-31 License information for E-UTRAN to UTRAN CS/PS steering
Feature ID
Feature Name
License Control Item
NE
Sales Unit
TDLOFD-001033
CS Fallback to UTRAN
CS Fallback to UTRAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001019
PS Inter-RAT Mobility between E-UTRAN and UTRAN
PS Inter-RAT Mobility between E-UTRAN and GERAN(TDD)
eNodeB
per RRC Connected User
TDLOFD-001078
E-UTRAN to UTRAN CS/PS Steering
E-UTRAN to UTRAN CS/PS steering(TDD)
eNodeB
per RRC Connected User

7.9.3.2 Data Preparation

This section describes the data that you need to collect for setting parameters. Required data is data that you must collect for all scenarios. Collect scenario-specific data when necessary for a specific feature deployment scenario. You need to collect both required data and scenario-specific data based on requirements.
There are three types of data sources:
  • Network plan (negotiation not required): parameter values planned and set by the operator
  • Network plan (negotiation required): parameter values planned by the operator and negotiated with the EPC or peer transmission equipment
  • User-defined: parameter values set by users
Required Data
Data preparation for E-UTRAN to UTRAN CS/PS steering is similar to that for CSFB to UTRAN described in Required Data.
For details about required data preparation for PS services, see Mobility Management in Connected Mode Feature Parameter Description.
Scenario-specific Data
The following table describes the parameters that must be set in the ENodeBAlgoSwitch MO to set the handover mode and handover algorithm switches for E-UTRAN to UTRAN CS/PS steering.
Parameter Name
Parameter ID
Data Source
Setting Notes
Frequency Layer Switch
Network plan (negotiation not required)
It is recommended that E-UTRAN to UTRAN CS/PS steering be activated. Set FreqLayerSwtich based on the UE capability and network plan. To activate blind handovers, select the UtranFreqLayerBlindSwitch(UtranFreqLayerBlindSwitch) check box. To activate measurement-based handovers, select the UtranFreqLayerMeasSwitch(UtranFreqLayerMeasSwitch) check box.
The following table describes the parameters that must be set in the UTRANNFREQ MO to set the UTRAN priorities for PS and CS services.
Parameter Name
Parameter ID
Data Source
Setting Notes
CS service priority
Network plan (negotiation not required)
Set this parameter based on the network plan. Priority_0: Indicates that CS services are prohibited. Priority_16 and Priority_1 indicate the highest and lowest priorities, respectively. It is recommended UTRAN frequency priority be set as the highest one.
PS service priority
Network plan (negotiation not required)
Set this parameter based on the network plan. Priority_0: Indicates that PS services are prohibited. Priority_16 and Priority_1 indicate the highest and lowest priorities, respectively. It is recommended UTRAN frequency priority be set as the highest one.

7.9.3.3 Activation

Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs
Enter the values of the parameters listed in Table 7-32 in a summary data file, which also contains other data for the new eNodeBs to be deployed. Then, import the summary data file into the CME for batch configuration. For detailed instructions, see section "Creating eNodeBs in Batches" in the initial configuration guide for the eNodeB.
The summary data file may be a scenario-specific file provided by the CME or a customized file, depending on the following conditions:
  • The MOs in Table 7-32 are contained in a scenario-specific summary data file. In this situation, set the parameters in the MOs, and then verify and save the file.
  • Some MOs in Table 7-32 are not contained in a scenario-specific summary data file. In this situation, customize a summary data file to include the MOs before you can set the parameters.
Table 7-32 Parameters for E-UTRAN to UTRAN CS/PS steering
MO
Sheet in the Summary Data File
Parameter Group
Remarks
ENodeBAlgoSwitch
ENodeBAlgoSwitch
Frequency Layer Switch
User-defined template
UtranNFreq
UtranNFreq
Local cell ID, Downlink UARFCN, CS service priority, and PS service priority
User-defined template
Using the CME to Perform Batch Configuration for Existing eNodeBs
Batch reconfiguration using the CME is the recommended method to activate a feature on existing eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure is as follows:
  1. Choose CME > Advanced > Customize Summary Data File from the main menu of an M2000 client, or choose Advanced > Customize Summary Data File from the main menu of a CME client, to customize a summary data file for batch reconfiguration.
    NOTE:
    For context-sensitive help on a current task in the client, press F1.
  2. Choose CME > LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application > Export Data >Export Base Station Bulk Configuration Data from the main menu of the CME client, to export the eNodeB data stored on the CME into the customized summary data file.
  3. In the summary data file, set the parameters in the MOs listed in "Using the CME to Perform Batch Configuration for Newly Deployed eNodeBs" and close the file.
  4. Choose CME > LTE Application > Import Data > Import Base Station Bulk Configuration Data from the main menu of the M2000 client, or choose LTE Application> Import Data > Import Base Station Bulk Configuration Data from the main menu of the CME client, to import the summary data file into the CME.
  5. Choose CME > Planned Area > Export Incremental Scripts from the main menu of the M2000 client, or choose Area Management > Planned Area > Export Incremental Scripts from the main menu of the CME client, to export and activate the incremental scripts.
Using the CME to Perform Single Configuration
On the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB. The procedure is as follows:
  1. In the planned data area, click Base Station in the upper left corner of the configuration window.
  2. In area 1 shown in Figure 7-10, select the eNodeB to which the MOs belong.
    Figure 7-10 MO search and configuration window
  3. On the Search tab page in area 2, enter an MO name, for example, CELL.
  4. In area 3, double-click the MO in the Object Name column. All parameters in this MO are displayed in area 4.
  5. Set the parameters in area 4 or 5.
  6. Choose CME > Planned Area > Export Incremental Scripts (M2000 client mode), or choose Area Management > Planned Area > Export Incremental Scripts (CME client mode), to export and activate the incremental scripts.
Using MML Commands
  1. Configure TDLOFD-001033 CS Fallback to UTRAN. For details, see 7.1.3.3 Activation.
  2. Configure TDLOFD-001019 PS Inter-RAT Mobility between E-UTRAN and UTRAN to verify the mobility function of PS services. For details, see Mobility Management in Connected Mode Feature Parameter Description.
  3. Configure the Frequency Layer Switch parameter for E-UTRAN to UTRAN CS/PS steering by running the MOD ENODEBALGOSWITCH command.
  4. Configure the CS service priority and PS service priority parameters by running the MODUTRANNFREQ command.

7.9.3.4 Activation Observation

The activation observation procedure is as follows:
  1. Ensure that CSFB to UTRAN has been enabled.
  2. Configure two UTRAN frequencies represented by F1 and F2. The CS service priority on F1 is higher than that on F2, and the connect frequency priority on F2 is higher than that on F1.
  3. Enable a UE to camp on the E-UTRAN cell and originate a voice call.
  4. Observe CS services fall back to F1.
  5. Enable a UE to camp on the E-UTRAN cell and trigger coverage-based PS mobility. The UE falls back to F2.
Signaling Observation
You can observe the signaling procedures for E-UTRAN to UTRAN CS/PS steering, which is the same as that for CSFB to UTRAN described in 7.1.3.4 Activation Observation.
For details about procedures for PS mobility service based on E-UTRAN to UTRAN CS/PS steering, see Mobility Management in Connected Mode Feature Parameter Description.
Counter Observation
Verify that E-UTRAN to UTRAN CS/PS steering has taken effect by observing the L.CSFB.E2W and L.CSFB.E2W.Idle counters.

7.9.3.5 Deactivation

Using the CME to Perform Batch Configuration
Batch reconfiguration using the CME is the recommended method to deactivate a feature on eNodeBs. This method reconfigures all data, except neighbor relationships, for multiple eNodeBs in a single procedure. The procedure for feature deactivation is similar to that for feature activation described in Using the CME to Perform Batch Configuration for Existing eNodeBs. In the procedure, modify parameters according to Table 7-33.
Table 7-33 Parameters for E-UTRAN to UTRAN CS/PS steering
MO
Sheet in the Summary Data File
Parameter Group
Setting Notes
ENodeBAlgoSwitch
ENodeBAlgoSwitch
Frequency Layer Switch
Clear the UtranFreqLayerMeasSwitch(UtranFreqLayerMeasSwitch) and UtranFreqLayerBlindSwitch(UtranFreqLayerBlindSwitch) check boxes.
Using the CME to Perform Single Configuration
On the CME, set parameters according to Table 7-33. For detailed instructions, see Using the CME to Perform Single Configuration for feature activation.
Using MML Commands
Run the MOD ENODEBALGOSWITCH command with the UtranFreqLayerMeasSwitch(UtranFreqLayerMeasSwitch) and UtranFreqLayerBlindSwitch(UtranFreqLayerBlindSwitch) check boxes cleared under the HoAlgoSwitch parameter.

7.9.3.6 MML Command Examples

NOTE:
The parameters in this section are for reference only. Configure the parameters depending on network requirements.
Activating E-UTRAN to UTRAN CS/PS Steering
CSFB steering to UTRAN requires CSFB to UTRAN. For details about how to activate CSFB steering to UTRAN, see 7.1.3.6 MML Command Examples.
For details about MML commands related to E-UTRAN to UTRAN CS/PS steering, see the following examples. Set this parameter based on the network plan.
//To turn on the frequency layer switch, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=FreqLayerSwtich=UtranFreqLayerMeasSwitch-1&UtranFreqLayerBlindSwitch-1;
//To configure the CS and PS frequency priorities for UTRAN frequencies, run the following command:
MOD UTRANNFREQ: LocalCellId=0, UtranDlArfcn=10700, CsPriority=Priority_16, ConnFreqPriority=8;
Deactivating E-UTRAN to UTRAN CS/PS Steering
//To deactivate CSFB steering to UTRAN, run the following command:
MOD ENODEBALGOSWITCH: HoAlgoSwitch=FreqLayerSwtich=UtranFreqLayerMeasSwitch-0&UtranFreqLayerBlindSwitch-0;

7.10 Performance Optimization

7.10.1 Performance Monitoring

CSFB allows UEs under LTE coverage to shift to CS networks when CS services arrive. Use the L.CSFB.PrepAtt and L.CSFB.PrepSucc counters to monitor CSFB performance. Use the L.CSFB.E2W and L.CSFB.E2G counters (corresponding to UMTS and GSM, respectively) to distinguish between the target CS networks.
Use the L.RRCRedirection.E2W.CSFB, L.RRCRedirection.E2G.CSFB, L.IRATHO.E2W.CSFB.PrepAttOut, and L.IRATHO.E2G.CSFB.PrepAttOut counters to monitor the CSFB mechanisms including redirections and handovers.
NOTE:
CSFB is an end-to-end service. The performance counters on the LTE side only include the success rate of the CSFB procedure on the LTE side. Therefore, the performance counters on the LTE side cannot directly show the user experience of the CSFB procedure. It is recommended that you perform drive tests and use the performance counters on the UE side to indicate the actual user experience of the CSFB procedure.
The number of SRVCC-triggered CSFB attempts is not calculated in the associated counters.

7.10.2 Parameter Optimization

Blind Handovers for CSFB

Compared with measurement-based handovers, blind handovers have shorter access delays but a lower handover success rate.
Set blind-handover priorities of different systems according to the operator's policy. When the handover success rate or service setup success rate is low due to poor UTRAN or GERAN coverage, adjust the blind-handover priorities for different systems or deactivate blind handovers to improve CSFB performance.
The following table describes the parameters that must be set in the CSFallBackBlindHoCfg MO to set the blind-handover priorities of different systems for CSFB.
Parameter Name
Parameter ID
Data Source
Setting Notes
CN Operator ID
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the ID of the operator whose inter-RAT blind-handover priorities are to be set.
Highest priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to UTRAN by default and specifies the high-priority system to be considered in blind handovers for CSFB.
Second priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to GERAN by default and specifies the medium-priority system to be considered in blind handovers for CSFB. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatLowestPri parameters.
Lowest priority InterRat
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter is set to CDMA2000 by default and specifies the low-priority system to be considered in blind handovers for CSFB. Ensure that this parameter is set to a value different from the InterRatHighestPri and InterRatSecondPri parameters.
The following table describes the parameter in the ENodeBAlgoSwitch MO to activate or deactivate blind handovers.
Parameter Name
Parameter ID
Data Source
Setting Notes
Handover Mode switch
Network plan (negotiation not required)
To activate blind handovers, select the BlindHoSwitch(BlindHoSwitch) check box. A blind handover to an inter-RAT cell can be performed only if the blind handover priority is specified for the inter-RAT cell. Compared with measurement-based handovers, blind handovers have shorter access delays but a lower handover success rate.
To deactivate blind handovers, clear the BlindHoSwitch(BlindHoSwitch) check box.

Measurement-based Handovers for CSFB

An appropriate event B1 threshold for CSFB ensures that inter-RAT handovers are triggered in a timely manner. A high threshold results in a low probability of triggering event B1, thereby affecting user experience. A low threshold results in a high probability of triggering event B1, but causes a high probability of incorrect handover decisions and a low handover success rate. Tune this threshold based on site conditions.
Event B1 for CSFB has a time-to-trigger parameter. This parameter lowers the probability of incorrect handover decisions and raises the handover success rate. However, if the value of this parameter is too large, CSFB delay is extended, affecting user experience. Tune this parameter based on site conditions.
Appropriate settings of the threshold and time-to-trigger for event B1 raise the handover success rate and lower the call drop rate. The related parameters are as follows:
  1. CSFB to UTRAN: CsfbHoUtranB1ThdRscp, CsfbHoUtranB1ThdEcn0, and CsfbHoUtranTimeToTrig
  2. CSFB to GERAN: CsfbHoGeranB1Thd and CsfbHoGeranTimeToTrig
  3. CSFB to CDMA2000 1xRTT: CsfbHoCdmaB1ThdPs and CsfbHoCdmaTimeToTrig
These parameters belong to the CSFALLBACKHO MO and are described in the following table.
Parameter Name
Parameter ID
Data Source
Setting Notes
Local cell ID
Network plan (negotiation not required)
Set this parameter based on the network plan.
CSFB Utran EventB1 Time To Trig
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the time-to-trigger for event B1 in CSFB to UTRAN. When CSFB to UTRAN is required, this parameter must be set, because it is used by UEs as one of the conditions for triggering event B1. When a UE detects that the signal quality in at least one UTRAN cell meets the entering condition, it does not immediately send a measurement report to the eNodeB. Instead, the UE sends a measurement report only when the signal quality has met the entering condition throughout a period specified by this parameter. An appropriate value for this parameter reduces the probability of random events B1 and the average number of handovers, thereby eliminating unnecessary handovers.
CSFB UTRAN EventB1 RSCP Trigger Threshold
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the RSCP threshold for event B1 in CSFB to UTRAN. When CSFB to UTRAN is required, this parameter must be set, because it is used by UEs as one of the conditions for triggering event B1. Event B1 is triggered when the RSCP measured by the UE is higher than the value of this parameter and all other conditions are also met.
CSFB UTRAN EventB1 ECN0 Trigger Threshold
Network plan (negotiation not required)
This parameter specifies the Ec/No threshold for event B1 in CSFB to UTRAN. When CSFB to UTRAN is required, this parameter must be set, because it is used by UEs as one of the conditions for triggering event B1. Event B1 is triggered when the Ec/No measured by the UE is higher than the value of this parameter and all other conditions are also met. Set this parameter to a large value for a cell with a large signal fading variance in order to reduce the probability of unnecessary handovers. Set this parameter to a small value for a cell with a small signal fading variance in order to ensure timely handovers.
CSFB GERAN EventB1 Trigger Threshold
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the RSSI threshold for event B1 in CSFB to GERAN. Event B1 is triggered when the measured RSSI of a GERAN cell reaches the value of this parameter and all other conditions are also met.
CSFB Geran EventB1 Time To Trig
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the time-to-trigger for event B1 in CSFB to GERAN. When CSFB to GERAN is required, this parameter must be set, because it is used by UEs as one of the conditions for triggering event B1. When a UE detects that the signal quality in at least one GERAN cell meets the entering condition, it does not immediately send a measurement report to the eNodeB. Instead, the UE sends a measurement report only when the signal quality has met the entering condition throughout a period specified by this parameter. An appropriate value for this parameter reduces the probability of random events B1 and the average number of handovers, thereby eliminating unnecessary handovers.
CSFB CDMA2000 EventB1 Trigger Threshold
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the pilot strength threshold for event B1 in CSFB to CDMA2000. Event B1 is triggered when the measured pilot strength of a CDMA2000 cell reaches the value of this parameter and all other conditions are also met.
CSFB CDMA EventB1 Time To Trig
Network plan (negotiation not required)
Set this parameter based on the network plan. This parameter specifies the time-to-trigger for event B1 in CSFB to CDMA2000. When CSFB to CDMA2000 is required, this parameter must be set, because it is used by UEs as one of the conditions for triggering event B1. When a UE detects that the signal quality in at least one CDMA cell meets the entering condition, it does not immediately send a measurement report to the eNodeB. Instead, the UE sends a measurement report only when the signal quality has met the entering condition throughout a period specified by this parameter. An appropriate value for this parameter reduces the probability of random events B1 and the average number of handovers, thereby eliminating unnecessary handovers.

7.10.3 EBC Description

Table 7-34 describes the event-based counters (EBCs) for CSFB.
Table 7-34 EBCs for CSFB
Event Name
Counter Name
Counter Description
Value
PRIVATE_RRC_CON_REL
ucRedirectionTrigger
Indicator for Redirection Trigger
0: CSFB 1: others
ucCSFBHighPriority
Emergency Call Indicator
0: indicates a non-emergency call. 1: indicates an emergency call.
ucSIBInfo
Indicator for Including Target Cell SIB in RRC Connection Release Message
0: indicates that the SIB information of the target cell is not included in the RRC Connection Release message. 1: indicates that the SIB information of the target cell is included in the RRC Connection Release message.
ucTargetType
Target Cell RAT
0: indicates that the target cell is an E-UTRAN cell. 1: indicates that the target cell is a UTRAN cell. 2: indicates that the target cell is a GERAN cell.
PRIVATE_INTER_RAT_HO
ucHoType
Handover Type: Intra-Frequency/Inter-Frequency/Inter-RAT
1: indicates an intra-frequency handover. 2: indicates an inter-frequency handover. 3: indicates a handover to UTRAN. 4: indicates a handover to TD-SCDMA. 5: indicates a handover to CDMA2000. 6: indicates a handover to GERAN.
ucHoTrigger
Handover Trigger
0: indicates a reserved value. 1: indicates a distance-based handover. 2: indicates a coverage-based handover. 3: indicates a load-based handover.
ucChoice
Cause Category
0: indicates that the procedure is complete. 1: indicates that the procedure fails due to radio-network-layer faults. 2: indicates that the procedure fails due to transport-layer faults. 3: indicates that the procedure fails due to NAS faults. 4: indicates that the procedure fails due to protocol-layer faults. 5: indicates that the procedure fails due to other faults.
ucCauseValue
Cause Value
23: S1_CS_FALLBACK
ucCSFBHighPriority
Indicator for Emergency Call-Triggered CSFB
0: indicates a non-emergency call. 1: indicates an emergency call.

7.11 Troubleshooting

7.11.1 Fault 1

Fault Description

A UE reselects an inter-RAT neighboring cell directly after initiating a voice call in an E-UTRAN cell, and the S1 interface tracing result shows that CSFB is not triggered.

Fault Handling

  1. Create an S1 interface tracing task, enable the UE to camp on the E-UTRAN cell again, and check whether the value of the information element (IE) ePS-attach-type-value is "combined-attach" in the traced Attach Request message.
    • If yes, go to 2.
    • If not, replace the UE with one that supports combined EPS/IMSI attach, and try again.
  2. Check whether the traced Attach Accept message includes the IE cs-domain-not-available.
    • If yes, go to 3.c.
    • If not, contact Huawei technical support.
  3. Contact the vendors of core network equipment to ensure the following:
    1. Attach procedures to the CS domain are allowed according to the subscription data on the HSS.
    2. The core network supports CSFB.
    3. The SGs interface is correctly configured.

7.11.2 Fault 2

Fault Description

An eNodeB delivers an RRC Connection Reconfiguration message to a UE that has initiated a voice call in the LTE network, but the eNodeB does not receive a measurement report.

Fault Handling

  1. Check whether the RRC Connection Reconfiguration message contains B1-related measurement configurations and whether the information about the inter-RAT systems in the configuration is correct.
    • If yes, go to 2.
    • If not, rectify the fault and try again. If the faults persist, contact Huawei technical support.
  2. Check whether the coverage of the inter-RAT neighboring cell is good enough. If the coverage is not good enough, adjust B1-related parameters or use CSFB based on blind handovers. For details about how to adjust B1-related parameters, see Mobility Management in Connected Mode Feature Parameter Description.

7.11.3 Fault 3

Fault Description

When blind handovers are configured as the preferred choice in the operator's policy, a blind handover based on CSFB is not triggered after a UE initiates a voice call. Instead, the eNodeB delivers an inter-RAT measurement configuration to the UE.

Fault Handling

  1. Run the LST ENODEBALGOSWITCH command and check the setting of BlindHoSwitch under the Handover Mode switch parameter. If BlindHoSwitch is Off, run the MOD ENODEBALGOSWITCH command with the BlindHoSwitch(BlindHoSwitch) check box under the HoModeSwitch parameter selected. In addition, check the CSFB mechanism and perform the following steps:
    • If CSFB to UTRAN is required, go to 2.
    • If CSFB to GERAN is required, go to 3.
  2. Run the LST UTRANNCELL command and check whether Blind handover priority is 0 for a neighboring UTRAN cell for incoming blind handovers.
    • If Blind handover priority is 0, blind handovers to this cell are not allowed. In this case, run the MOD UTRANNCELL command with the Blind HandOver Priority parameter set to a value other than 0.
    • If Blind handover priority has been configured, contact Huawei technical support.
  3. Run the LST GERANNCELL command and check whether Blind handover priority is 0 for a neighboring GERAN cell for incoming blind handovers.
    • If Blind handover priority is 0, blind handovers to this cell are not allowed. In this case, run the MOD GERANNCELL command with the Blind handover priority parameter set to a value other than 0.
    • If Blind handover priority has been configured, contact Huawei technical support.

8 Parameters

Table 8-1 Parameter description
MO
Parameter ID
MML Command
Feature ID
Feature Name
Description
CSFallBackBlindHoCfg
IdleCsfbHighestPri
MOD CSFALLBACKBLINDHOCFG
LST CSFALLBACKBLINDHOCFG
LOFD-001035 / TDLOFD-001035
LOFD-001088 / TDLOFD-001088
LOFD-001089 / TDLOFD-001089
TDLOFD-001090
CS Fallback to CDMA2000 1xRTT
CS Fallback Steering to UTRAN
CS Fallback Steering to GERAN
Enhanced CS Fallback to CDMA2000 1xRTT
Meaning: Indicates the highest-priority RAT for CSFB initiated by a UE in idle mode. It is UTRAN by default. If this parameter is set to UTRAN, GERAN, or CDMA2000, the highest-priority RAT is UTRAN, GERAN, or CDMA2000, respectively.
GUI Value Range: UTRAN, GERAN, CDMA2000
Unit: None
Actual Value Range: UTRAN, GERAN, CDMA2000
Default Value: UTRAN
CSFallBackBlindHoCfg
IdleCsfbSecondPri
MOD CSFALLBACKBLINDHOCFG
LST CSFALLBACKBLINDHOCFG
LOFD-001035 / TDLOFD-001035
LOFD-001088 / TDLOFD-001088
LOFD-001089 / TDLOFD-001089
TDLOFD-001090
CS Fallback to CDMA2000 1xRTT
CS Fallback Steering to UTRAN
CS Fallback Steering to GERAN
Enhanced CS Fallback to CDMA2000 1xRTT
Meaning: Indicates the medium-priority RAT for CSFB initiated by a UE in idle mode. It is GERAN by default. If this parameter is set to UTRAN, GERAN, or CDMA2000, the medium-priority RAT is UTRAN, GERAN, or CDMA2000, respectively. If this parameter is set to NULL, no medium-priority RAT is specified and only the highest-priority RAT can be selected for CSFB initiated by a UE in idle mode.
GUI Value Range: UTRAN, GERAN, CDMA2000, NULL
Unit: None
Actual Value Range: UTRAN, GERAN, CDMA2000, NULL
Default Value: GERAN
CSFallBackBlindHoCfg
IdleCsfbLowestPri
MOD CSFALLBACKBLINDHOCFG
LST CSFALLBACKBLINDHOCFG
LOFD-001035 / TDLOFD-001035
LOFD-001088 / TDLOFD-001088
LOFD-001089 / TDLOFD-001089
TDLOFD-001090
CS Fallback to CDMA2000 1xRTT
CS Fallback Steering to UTRAN
CS Fallback Steering to GERAN
Enhanced CS Fallback to CDMA2000 1xRTT
Meaning: Indicates the lowest-priority RAT for CSFB initiated by a UE in idle mode. It is CDMA2000 by default. If this parameter is set to UTRAN, GERAN, or CDMA2000, the lowest-priority RAT is UTRAN, GERAN, or CDMA2000, respectively. If this parameter is set to NULL, no lowest-priority RAT is specified and only the highest- or medium-priority RAT can be selected for CSFB initiated by a UE in idle mode.
GUI Value Range: UTRAN, GERAN, CDMA2000, NULL
Unit: None
Actual Value Range: UTRAN, GERAN, CDMA2000, NULL
Default Value: CDMA2000
CSFallBackBlindHoCfg
InterRatHighestPri
MOD CSFALLBACKBLINDHOCFG
LST CSFALLBACKBLINDHOCFG
LOFD-001033 / TDLOFD-001033
LOFD-001034 / TDLOFD-001034
LOFD-001035 / TDLOFD-001035
LOFD-001019 / TDLOFD-001019
LOFD-001020 / TDLOFD-001020
LOFD-001021
TDLOFD-001052
TDLOFD-001053
TDLOFD-001090
TDLOFD-001043
TDLOFD-001072
TDLOFD-001046
TDLOFD-001073
CS Fallback to UTRAN
CS Fallback to GERAN
CS Fallback to CDMA2000 1xRTT
PS Inter-RAT Mobility between E-UTRAN and UTRAN
PS Inter-RAT Mobility between E-UTRAN and GERAN
PS Inter-RAT Mobility between E-UTRAN and CDMA2000
Flash CS Fallback to UTRAN
Flash CS Fallback to GERAN
Enhanced CS Fallback to CDMA2000 1xRTT
Service based Inter-RAT handover to UTRAN
Distance based Inter-RAT handover to UTRAN
Service based Inter-RAT handover to GERAN
Distance based Inter-RAT handover to GERAN
Meaning: Indicates the highest-priority RAT for handovers. It is UTRAN by default. If this parameter is set to UTRAN, GERAN, or CDMA2000, the highest-priority RAT is UTRAN, GERAN, or CDMA2000, respectively.
GUI Value Range: UTRAN, GERAN, CDMA2000
Unit: None
Actual Value Range: UTRAN, GERAN, CDMA2000
Default Value: UTRAN
CSFallBackBlindHoCfg
InterRatSecondPri
MOD CSFALLBACKBLINDHOCFG
LST CSFALLBACKBLINDHOCFG
LOFD-001033 / TDLOFD-001033
LOFD-001034 / TDLOFD-001034
LOFD-001035 / TDLOFD-001035
LOFD-001019 / TDLOFD-001019
LOFD-001020 / TDLOFD-001020
LOFD-001021
TDLOFD-001052
TDLOFD-001053
TDLOFD-001090
TDLOFD-001043
TDLOFD-001072
TDLOFD-001046
TDLOFD-001073
CS Fallback to UTRAN
CS Fallback to GERAN
CS Fallback to CDMA2000 1xRTT
PS Inter-RAT Mobility between E-UTRAN and UTRAN
PS Inter-RAT Mobility between E-UTRAN and GERAN
PS Inter-RAT Mobility between E-UTRAN and CDMA2000
Flash CS Fallback to UTRAN
Flash CS Fallback to GERAN
Enhanced CS Fallback to CDMA2000 1xRTT
Service based Inter-RAT handover to UTRAN
Distance based Inter-RAT handover to UTRAN
Service based Inter-RAT handover to GERAN
Distance based Inter-RAT handover to GERAN
Meaning: Indicates the medium-priority RAT for handovers. It is GERAN by default. If this parameter is set to UTRAN, GERAN, or CDMA2000, the medium-priority RAT is UTRAN, GERAN, or CDMA2000, respectively. If this parameter is set to NULL, no medium-priority RAT is specified and only the highest-priority RAT can be selected for handovers.
GUI Value Range: UTRAN, GERAN, CDMA2000, NULL
Unit: None
Actual Value Range: UTRAN, GERAN, CDMA2000, NULL
Default Value: GERAN
CSFallBackBlindHoCfg
InterRatLowestPri
MOD CSFALLBACKBLINDHOCFG
LST CSFALLBACKBLINDHOCFG
LOFD-001033 / TDLOFD-001033
LOFD-001034 / TDLOFD-001034
LOFD-001035 / TDLOFD-001035
LOFD-001019 / TDLOFD-001019
LOFD-001020 / TDLOFD-001020
LOFD-001021
TDLOFD-001052
TDLOFD-001053
TDLOFD-001090
TDLOFD-001043
TDLOFD-001072
TDLOFD-001046
TDLOFD-001073
CS Fallback to UTRAN
CS Fallback to GERAN
CS Fallback to CDMA2000 1xRTT
PS Inter-RAT Mobility between E-UTRAN and UTRAN
PS Inter-RAT Mobility between E-UTRAN and GERAN
PS Inter-RAT Mobility between E-UTRAN and CDMA2000
Flash CS Fallback to UTRAN
Flash CS Fallback to GERAN
Enhanced CS Fallback to CDMA2000 1xRTT
Service based Inter-RAT handover to UTRAN
Distance based Inter-RAT handover to UTRAN
Service based Inter-RAT handover to GERAN
Distance based Inter-RAT handover to GERAN
Meaning: Indicates the lowest-priority RAT for handovers. It is CDMA2000 by default. If this parameter is set to UTRAN, GERAN, or CDMA2000, the lowest-priority RAT is UTRAN, GERAN, or CDMA2000, respectively. If this parameter is set to NULL, no lowest-priority RAT is specified and only the highest- or medium-priority RAT can be selected for handovers.
GUI Value Range: UTRAN, GERAN, CDMA2000, NULL
Unit: None
Actual Value Range: UTRAN, GERAN, CDMA2000, NULL
Default Value: CDMA2000
CSFallBackPolicyCfg
IdleModeCsfbHoPolicyCfg
MOD CSFALLBACKPOLICYCFG
LST CSFALLBACKPOLICYCFG
LOFD-001088
LOFD-001089
CS Fallback Steering to UTRAN
CS Fallback Steering to GERAN
Meaning: Indicates the CSFB policy for a UE in idle mode. The policy can be PS handover, CCO, or redirection.
GUI Value Range: REDIRECTION, CCO_HO, PS_HO
Unit: None
Actual Value Range: REDIRECTION, CCO_HO, PS_HO
Default Value: REDIRECTION:On, CCO_HO:On, PS_HO:On
CSFallBackPolicyCfg
CsfbHoPolicyCfg
MOD CSFALLBACKPOLICYCFG
LST CSFALLBACKPOLICYCFG
LOFD-001088
LOFD-001089
CS Fallback Steering to UTRAN
CS Fallback Steering to GERAN
Meaning: Indicates the CSFB policy for a UE in connected mode. If the CSFB steering function is disabled, this parameter also applies to UEs in idle mode. The policy can be PS handover, CCO, or redirection.
GUI Value Range: REDIRECTION, CCO_HO, PS_HO
Unit: None
Actual Value Range: REDIRECTION, CCO_HO, PS_HO
Default Value: REDIRECTION:On, CCO_HO:On, PS_HO:On
UtranNFreq
CsPsMixedPriority
ADD UTRANNFREQ
MOD UTRANNFREQ
LST UTRANNFREQ
LOFD-001033 / TDLOFD-001033
LOFD-001078 / TDLBFD-001078
CS Fallback to UTRAN
E-UTRAN to UTRAN CS/PS Steering
Meaning: Indicates the priority for the neighboring UTRAN frequency to carry CS+PS combined services. In measurement-based CSFB to UTRAN, if UtranCsfbSteeringSwitch and UtranFreqLayerMeasSwitch are turned on, the eNodeB determines the UTRAN frequency to be delivered to a UE in RRC_CONNECTED mode based on the CS+PS combined service priorities. The eNodeB preferentially delivers the UTRAN frequency with the highest CS+PS combined service priority to the UE. In blind CSFB to UTRAN, if UtranCsfbSteeringSwitch and UtranFreqLayerBlindSwitch are turned on, the target cell is selected based on the CS+PS combined service priorities. The cell on the UTRAN frequency with the highest CS+PS combined service priority is preferentially selected. If this parameter is set to Priority_0(Priority 0), the UTRAN frequency is not included in CS+PS combined service priority arrangement.
GUI Value Range: Priority_0(Priority 0), Priority_1(Priority 1), Priority_2(Priority 2), Priority_3(Priority 3), Priority_4(Priority 4), Priority_5(Priority 5), Priority_6(Priority 6), Priority_7(Priority 7), Priority_8(Priority 8), Priority_9(Priority 9), Priority_10(Priority 10), Priority_11(Priority 11), Priority_12(Priority 12), Priority_13(Priority 13), Priority_14(Priority 14), Priority_15(Priority 15), Priority_16(Priority 16)
Unit: None
Actual Value Range: Priority_0, Priority_1, Priority_2, Priority_3, Priority_4, Priority_5, Priority_6, Priority_7, Priority_8, Priority_9, Priority_10, Priority_11, Priority_12, Priority_13, Priority_14, Priority_15, Priority_16
Default Value: Priority_2(Priority 2)
InterRatHoComm
CellInfoMaxUtranCellNum
MOD INTERRATHOCOMM
LST INTERRATHOCOMM
None
None
Meaning: Indicates the maximum number of UTRAN cell system information messages that can be transmitted during a flash redirection procedure.
GUI Value Range: 1~16
Unit: None
Actual Value Range: 1~16
Default Value: 8
InterRatHoComm
CellInfoMaxGeranCellNum
MOD INTERRATHOCOMM
LST INTERRATHOCOMM
None
None
Meaning: Indicates the maximum number of GERAN cell system information messages that can be transmitted during a flash redirection procedure.
GUI Value Range: 1~32
Unit: None
Actual Value Range: 1~32
Default Value: 8
ENodeBAlgoSwitch
HoAlgoSwitch
MOD ENODEBALGOSWITCH
LST ENODEBALGOSWITCH
LBFD-00201801 / TDLBFD-00201801
LBFD-00201802 / TDLBFD-00201802
LOFD-001019 / TDLOFD-001019
LOFD-001020 / TDLOFD-001020
LOFD-001021
LOFD-001022 / TDLOFD-001022
LOFD-001023 / TDLOFD-001023
LOFD-001033 / TDLOFD-001033
LOFD-001034 / TDLOFD-001034
LOFD-001035
LOFD-001043 / TDLOFD-001043
LOFD-001044 / TDLOFD-001044
LOFD-001046 / TDLOFD-001046
LBFD-00201805
LOFD-001088
LOFD-001089
Coverage Based Intra-frequency Handover
Coverage Based Inter-frequency Handover
PS Inter-RAT Mobility between E-UTRAN and UTRAN
PS Inter-RAT Mobility between E-UTRAN and GERAN
PS Inter-RAT Mobility between E-UTRAN and CDMA2000
SRVCC to UTRAN
SRVCC to GERAN
CS Fallback to UTRAN
CS Fallback to GERAN
CS Fallback to CDMA2000 1xRTT
Service based inter-RAT handover to UTRAN
Inter-RAT Load Sharing to UTRAN
Service based inter-RAT handover to GERAN
Service Based Inter-frequency Handover
CS Fallback Flexible Steering to UTRAN
CS Fallback Flexible Steering to GERAN
Meaning: Indicates the collective switch used to enable or disable. Flash CS fallback to UTRAN: If the switch for CS fallback to UTRAN is turned off, this switch does not take effect; Flash CS fallback to GERAN: If the switch for CS fallback to GERAN is turned off, this switch does not take effect. CsfbAdaptiveBlindHoSwitch:If BlindHoSwitch is turned off, this switch does not take effect.
GUI Value Range: IntraFreqCoverHoSwitch(IntraFreqCoverHoSwitch), InterFreqCoverHoSwitch(InterFreqCoverHoSwitch), UtranCsfbSwitch(UtranCsfbSwitch), GeranCsfbSwitch(GeranCsfbSwitch), Cdma1xRttCsfbSwitch(Cdma20001xRttCsfbSwitch), UtranServiceHoSwitch(UtranServiceHoSwitch), GeranServiceHoSwitch(GeranServiceHoSwitch), CdmaHrpdServiceHoSwitch(Cdma2000HrpdServiceHoSwitch), Cdma1xRttServiceHoSwitch(Cdma20001xRttServiceHoSwitch), UlQualityInterRATHoSwitch(UlQualityInterRATHoSwitch), InterPlmnHoSwitch(InterPlmnHoSwitch), UtranFlashCsfbSwitch(UtranFlashCsfbSwitch), GeranFlashCsfbSwitch(GeranFlashCsfbSwitch), ServiceBasedInterFreqHoSwitch(ServiceBasedInterFreqHoSwitch), UlQualityInterFreqHoSwitch(UlQualityInterFreqHoSwitch), CsfbAdaptiveBlindHoSwitch(CsfbAdaptiveBlindHoSwitch), UtranCsfbSteeringSwitch(UtranCsfbSteeringSwitch), GeranCsfbSteeringSwitch(GeranCsfbSteeringSwitch), CSFBLoadInfoSwitch(CSFBLoadInfoSwitch), Cdma1XrttEcsfbSwitch(Cdma1XrttEcsfbSwitch), EmcBlindHoA1Switch(EmcBlindHoA1Switch), EmcInterFreqBlindHoSwitch(EmcInterFreqBlindHoSwitch)
Unit: None
Actual Value Range: IntraFreqCoverHoSwitch, InterFreqCoverHoSwitch, UtranCsfbSwitch, GeranCsfbSwitch, Cdma1xRttCsfbSwitch, UtranServiceHoSwitch, GeranServiceHoSwitch, CdmaHrpdServiceHoSwitch, Cdma1xRttServiceHoSwitch, UlQualityInterRATHoSwitch, InterPlmnHoSwitch, UtranFlashCsfbSwitch, GeranFlashCsfbSwitch, ServiceBasedInterFreqHoSwitch, UlQualityInterFreqHoSwitch, CsfbAdaptiveBlindHoSwitch, UtranCsfbSteeringSwitch, GeranCsfbSteeringSwitch, CSFBLoadInfoSwitch, Cdma1XrttEcsfbSwitch, EmcBlindHoA1Switch, EmcInterFreqBlindHoSwitch
Default Value: IntraFreqCoverHoSwitch:On, InterFreqCoverHoSwitch:On, UtranCsfbSwitch:Off, GeranCsfbSwitch:Off, Cdma20001xRttCsfbSwitch:Off, UtranServiceHoSwitch:Off, GeranServiceHoSwitch:Off, Cdma2000HrpdServiceHoSwitch:Off, Cdma20001xRttServiceHoSwitch:Off, UlQualityInterRATHoSwitch:Off, InterPlmnHoSwitch:Off, UtranFlashCsfbSwitch:Off, GeranFlashCsfbSwitch:Off, ServiceBasedInterFreqHoSwitch:Off, UlQualityInterFreqHoSwitch:Off, CsfbAdaptiveBlindHoSwitch:Off, UtranCsfbSteeringSwitch:Off, GeranCsfbSteeringSwitch:Off, CSFBLoadInfoSwitch:Off, Cdma1XrttEcsfbSwitch:Off, EmcBlindHoA1Switch:Off, EmcInterFreqBlindHoSwitch:Off
ENodeBAlgoSwitch
RimSwitch
MOD ENODEBALGOSWITCH
LST ENODEBALGOSWITCH
LOFD-001052 / TDLOFD-001052
LOFD-001053 / TDLOFD-001053
Flash CS Fallback to UTRAN
Flash CS Fallback to GERAN
Meaning: Indicates the collective switch for the RAN information management (RIM) function. UTRAN_RIM_SWITCH: Indicates the switch used to enable or disable the RIM procedure that requests event-driven multiple reports from UTRAN cells. If this switch is turned on, the eNodeB can send RAN-INFORMATION-REQUEST protocol data units (PDUs) to UTRAN cells to request multiple event-driven reports. If this switch is turned off, the eNodeB cannot send RAN-INFORMATION-REQUEST PDUs to UTRAN cells to request multiple event-driven reports. GERAN_RIM_SWITCH: Indicates the switch used to enable or disable the RIM procedure that requests event-driven multiple reports from GERAN cells. If this switch is turned on, the eNodeB can send RAN-INFORMATION-REQUEST PDUs to CERAN cells to request multiple event-driven reports. If this switch is turned off, the eNodeB cannot send RAN-INFORMATION-REQUEST PDUs to GERAN cells to request multiple event-driven reports.
GUI Value Range: UTRAN_RIM_SWITCH(UTRAN RIM Switch), GERAN_RIM_SWITCH(GERAN RIM Switch)
Unit: None
Actual Value Range: UTRAN_RIM_SWITCH, GERAN_RIM_SWITCH
Default Value: UTRAN RIM Switch:Off, GERAN RIM Switch:Off
ENodeBAlgoSwitch
HoModeSwitch
MOD ENODEBALGOSWITCH
LST ENODEBALGOSWITCH
LOFD-001019 / TDLOFD-001019
LOFD-001020 / TDLOFD-001020
LOFD-001021
LOFD-001022 / TDLOFD-001022
LOFD-001023 / TDLOFD-001023
LOFD-001033 / TDLOFD-001033
LOFD-001034 / TDLOFD-001034
LOFD-001035
LOFD-001043 / TDLOFD-001043
LOFD-001044 / TDLOFD-001044
LOFD-001045 / TDLOFD-001045
LOFD-001046 / TDLOFD-001046
PS Inter-RAT Mobility between E-UTRAN and UTRAN
PS Inter-RAT Mobility between E-UTRAN and GERAN
PS Inter-RAT Mobility between E-UTRAN and CDMA2000
SRVCC to UTRAN
SRVCC to GERAN
CS Fallback to UTRAN
CS Fallback to GERAN
CS Fallback to CDMA2000 1xRTT
Service based inter-RAT handover to UTRAN
Inter-RAT Load Sharing to UTRAN
Inter-RAT Load Sharing to GERAN
Service based inter-RAT handover to GERAN
Meaning: Indicates the switches corresponding to the inputs based on which the eNodeB determines handover policies. EutranVoipCapSwitch: This switch will be removed in later versions. In this version, the setting of this switch is still synchronized between the M2000 and the eNodeB, but it is no longer used internally. Therefore, avoid using this switch. BlindHoSwitch: This switch controls whether to enable or disable blind handovers during CS fallback. GeranNaccSwitch: This switch does not take effect if GeranCcoSwitch is disabled.
GUI Value Range: EutranVoipCapSwitch(EutranVoipCapSwitch), UtranVoipCapSwitch(UtranVoipCapSwitch), GeranVoipCapSwitch(GeranVoipCapSwitch), Cdma1xRttVoipCapSwitch(Cdma1xRttVoipCapSwitch), UtranPsHoSwitch(UtranPsHoSwitch), GeranPsHoSwitch(GeranPsHoSwitch), CdmaHrpdNonOtpimisedHoSwitch(CdmaHrpdNonOtpimisedHoSwitch), CdmaHrpdOptimisedHoSwitch(CdmaHrpdOptimisedHoSwitch), GeranNaccSwitch(GeranNaccSwitch), GeranCcoSwitch(GeranCcoSwitch), UtranSrvccSwitch(UtranSrvccSwitch), GeranSrvccSwitch(GeranSrvccSwitch), Cdma1xRttSrvccSwitch(Cdma1xRttSrvccSwitch), UtranRedirectSwitch(UtranRedirectSwitch), GeranRedirectSwitch(GeranRedirectSwitch), CdmaHrpdRedirectSwitch(CdmaHrpdRedirectSwitch), Cdma1xRttRedirectSwitch(Cdma1xRttRedirectSwitch), BlindHoSwitch(BlindHoSwitch), LcsSrvccSwitch(LcsSrvccSwitch), AutoGapSwitch(AutoGapSwitch)
Unit: None
Actual Value Range: EutranVoipCapSwitch, UtranVoipCapSwitch, GeranVoipCapSwitch, Cdma1xRttVoipCapSwitch, UtranPsHoSwitch, GeranPsHoSwitch, CdmaHrpdNonOtpimisedHoSwitch, CdmaHrpdOptimisedHoSwitch, GeranNaccSwitch, GeranCcoSwitch, UtranSrvccSwitch, GeranSrvccSwitch, Cdma1xRttSrvccSwitch, UtranRedirectSwitch, GeranRedirectSwitch, CdmaHrpdRedirectSwitch, Cdma1xRttRedirectSwitch, BlindHoSwitch, LcsSrvccSwitch, AutoGapSwitch
Default Value: EutranVoipCapSwitch:On, UtranVoipCapSwitch:Off, GeranVoipCapSwitch:Off, Cdma1xRttVoipCapSwitch:Off, UtranPsHoSwitch:Off, GeranPsHoSwitch:Off, CdmaHrpdNonOtpimisedHoSwitch:Off, CdmaHrpdOptimisedHoSwitch:Off, GeranNaccSwitch:Off, GeranCcoSwitch:Off, UtranSrvccSwitch:Off, GeranSrvccSwitch:Off, Cdma1xRttSrvccSwitch:Off, UtranRedirectSwitch:Off, GeranRedirectSwitch:Off, CdmaHrpdRedirectSwitch:Off, Cdma1xRttRedirectSwitch:Off, BlindHoSwitch:Off, LcsSrvccSwitch:Off, AutoGapSwitch:Off
EutranInterFreqNCell
BlindHoPriority
ADD EUTRANINTERFREQNCELL
MOD EUTRANINTERFREQNCELL
LST EUTRANINTERFREQNCELL
LBFD-00201802 / TDLBFD-00201802
LBFD-00201803 / TDLBFD-00201803
Coverage Based Inter-frequency Handover
Cell Selection and Reselection / Cell Selection and Re-selection
Meaning: Indicates the priority of the neighboring cell during handovers. The parameter values are divided into three segments, indicating the blind-handover priority, frequency-based-handover priority, and 0. Within the same segment, a larger parameter value indicates a higher priority. Blind handover is a process in which the eNodeB instructs a UE to hand over to a specified neighboring cell without measurements. If this parameter value is set to 0, blind handovers and frequency-based handovers cannot be performed. The parameter values 1 to 16 indicate the blind-handover priorities. The parameter values 17 to 32 indicate the frequency-based-handover priorities for frequency-based blind handovers and measurement-based handovers.
GUI Value Range: 0~32
Unit: None
Actual Value Range: 0~32
Default Value: 0
CSFallBackHo
CsfbHoUtranB1ThdRscp
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001033 / TDLOFD-001033
CS Fallback to UTRAN
Meaning: Indicates the RSCP threshold for event B1, which is used in CS fallback to UTRAN. When CS fallback to UTRAN is applicable, this parameter is set for UEs and used in the evaluation about whether to trigger event B1. This parameter indicates the RSCP requirement for the UTRAN cells to be included in the measurement report. A UE sends a measurement report related to event B1 to the eNodeB when the RSCP in at least one UTRAN cell exceeds this threshold and other triggering conditions are met. For details, see 3GPP TS 36.331.
GUI Value Range: -120~-25
Unit: dBm
Actual Value Range: -120~-25
Default Value: -106
CSFallBackHo
CsfbHoUtranB1ThdEcn0
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001033 / TDLOFD-001033
CS Fallback to UTRAN
Meaning: Indicates the Ec/No threshold for event B1, which is used in CS fallback to UTRAN. When CS fallback to UTRAN is required, this parameter is set for UEs and used in the evaluation about whether to trigger event B1. This parameter indicates the Ec/No requirement for the UTRAN cells to be included in the measurement report. A UE sends a measurement report related to event B1 to the eNodeB when the Ec/No in at least one UTRAN cell exceeds this threshold and other triggering conditions are met. For a cell with large signal fading variance, set this parameter to a large value to prevent unnecessary handovers. For a cell with small signal fading variance, set this parameter to a small value to ensure timely handovers. For details, see 3GPP TS 36.331.
GUI Value Range: -48~0
Unit: 0.5dB
Actual Value Range: -24~0, step:0.5
Default Value: -13
CSFallBackHo
CsfbHoGeranB1Thd
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001034 / TDLOFD-001034
CS Fall Back to GERAN
Meaning: Indicates the RSSI threshold for event B1 that is used in CS fallback to GERAN. A UE sends a measurement report related to event B1 to the eNodeB when the RSSI in at least one GERAN cell exceeds this threshold and other triggering conditions are met. For details, see 3GPP TS 36.331.
GUI Value Range: -110~-48
Unit: dBm
Actual Value Range: -110~-48
Default Value: -103
CSFallBackHo
CsfbHoUtranTimeToTrig
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001033 / TDLOFD-001033
CS Fallback to UTRAN
Meaning: Indicates the time-to-trigger for event B1 that is used in CS fallback to UTRAN. When CS fallback to UTRAN is applicable, this parameter is set for UEs and used in the evaluation of whether to trigger event B1. When detecting that the signal quality in at least one UTRAN cell meets the entering condition, the UE does not send a measurement report to the eNodeB immediately. Instead, the UE sends a report only when the signal quality continuously meets the entering condition during the time-to-trigger. This parameter helps decrease the number of occasionally triggered event reports, the average number of handovers, and the number of wrong handovers, and thus helps prevent unnecessary handovers. For details, see 3GPP TS 36.331.
GUI Value Range: 0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms, 1280ms, 2560ms, 5120ms
Unit: ms
Actual Value Range: 0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms, 1280ms, 2560ms, 5120ms
Default Value: 40ms
CSFallBackHo
CsfbHoGeranTimeToTrig
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001034 / TDLOFD-001034
CS Fall Back to GERAN
Meaning: Indicates the time-to-trigger for event B1 that is used in CS fallback to GERAN. When CS fallback to GERAN is applicable, this parameter is set for UEs and used in the evaluation of whether to trigger event B1. When detecting that the signal quality in at least one GERAN cell meets the entering condition, the UE does not send a measurement report to the eNodeB immediately. Instead, the UE sends a report only when the signal quality continuously meets the entering condition during the time-to-trigger. This parameter helps decrease the number of occasionally triggered event reports, the average number of handovers, and the number of wrong handovers, and thus helps prevent unnecessary handovers. For details, see 3GPP TS 36.331.
GUI Value Range: 0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms, 1280ms, 2560ms, 5120ms
Unit: ms
Actual Value Range: 0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms, 1280ms, 2560ms, 5120ms
Default Value: 40ms
CSFallBackHo
BlindHoA1ThdRsrp
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001052
LOFD-001053
Flash CSFB to Utran
Flash CSFB to Geran
Meaning: Indicates the RSRP threshold for event A1 associated with CSFB-triggered adaptive blind handovers. This parameter is set for a UE as a triggering condition of event A1 measurement related to a CSFB-triggered adaptive blind handover. This parameter specifies the RSRP threshold of the local cell above which a CSFB-triggered adaptive blind handover is triggered. If the RSRP value measured by the UE exceeds this threshold, this UE submits a measurement report related to event A1.
GUI Value Range: -141~-43
Unit: dBm
Actual Value Range: -141~-43
Default Value: -80
ENodeBAlgoSwitch
FreqLayerSwtich
MOD ENODEBALGOSWITCH
LST ENODEBALGOSWITCH
LBFD-002018 / TDLBFD-002018
LOFD-001087
Mobility Management
SRVCC Flexible Steering to UTRAN
Meaning: This parameter includes the following three switches: UtranFreqLayerMeasSwitch, UtranFreqLayerBlindSwitch, and UtranSrvccSwitch. UtranSrvccSwitch takes effect only when UtranFreqLayerMeasSwitch is turned on. If UtranFreqLayerMeasSwitch is turned on, the UTRAN hierarchy-based measurement algorithm takes effect for measurements related to coverage-based and CSFB-triggered handovers from EUTRAN to UTRAN. If UtranFreqLayerBlindSwitch is turned on, the UTRAN hierarchy-based blind-handover algorithm takes effect for coverage-based and CSFB-triggered blind handovers from EUTRAN toUTRAN. If UtranSrvccSwitch is turned on, the UTRAN SRVCC hierarchy-based measurement algorithm takes effect for SRVCC-triggered handovers from EUTRAN to UTRAN.
GUI Value Range: UtranFreqLayerMeasSwitch(UtranFreqLayerMeasSwitch), UtranFreqLayerBlindSwitch(UtranFreqLayerBlindSwitch), UtranSrvccSteeringSwitch(UtranSrvccSteeringSwitch)
Unit: None
Actual Value Range: UtranFreqLayerMeasSwitch, UtranFreqLayerBlindSwitch, UtranSrvccSteeringSwitch
Default Value: UtranFreqLayerMeasSwitch:Off, UtranFreqLayerBlindSwitch:Off, UtranSrvccSteeringSwitch:Off
UtranNCell
BlindHoPriority
ADD UTRANNCELL
MOD UTRANNCELL
LST UTRANNCELL
LBFD-002018 / TDLBFD-002018
Mobility Management
Meaning: Indicates the priority of the neighboring cell during blind handovers. Blind handover is a process in which the eNodeB instructs a UE to hand over to a specified neighboring cell. There are 32 priorities altogether. The priority has a positive correlation with the value of this parameter. Note that the value 0 indicates that blind handovers to the neighboring cell are not allowed.
GUI Value Range: 0~32
Unit: None
Actual Value Range: 0~32
Default Value: 0
UtranNFreq
ConnFreqPriority
ADD UTRANNFREQ
MOD UTRANNFREQ
LST UTRANNFREQ
LBFD-00201803 / TDLBFD-00201803
Cell Selection and Reselection
Meaning: Indicates the frequency priority based on which the eNodeB selects a target frequency for blind redirection or contains a frequency in a measurement configuration. If a blind redirection is triggered and the target neighboring cell is not specified, the eNodeB selects a target frequency based on this priority. If a measurement configuration is to be delivered, the eNodeB preferentially delivers a frequency with the highest priority. If this priority is set to 0 for a frequency, this frequency is not selected as the target frequency for a blind redirection. A larger value indicates a higher priority.
GUI Value Range: 0~8
Unit: None
Actual Value Range: 0~8
Default Value: 0
UtranNFreq
CsPriority
ADD UTRANNFREQ
MOD UTRANNFREQ
LST UTRANNFREQ
LOFD-001033 / TDLOFD-001033
LOFD-001078 / TDLBFD-001078
CS Fallback to UTRAN
E-UTRAN to UTRAN CS/PS Steering
Meaning: Indicates the priority for a neighboring UTRAN frequency to carry CS services. In coverage-based inter-RAT SRVCC or CSFB to UTRAN, if UtranFreqLayerMeasSwitch is turned on, the eNodeB determines the UTRAN frequency to be delivered to a UE based on CS service priorities. The eNodeB delivers the UTRAN frequency with the highest CS priority to the UE by default.In blind handovers for CSFB to UTRAN, if UtranFreqLayerBlindSwitch is turned on, the target cell for a blind handover is selected based on CS service priorities. The cell on the UTRAN frequency with the highest CS priority is selected by default.When this parameter is set to Priority_0 for a UTRAN frequency, the UTRAN frequency is not included in CS service priority arrangement.
GUI Value Range: Priority_0(Priority 0), Priority_1(Priority 1), Priority_2(Priority 2), Priority_3(Priority 3), Priority_4(Priority 4), Priority_5(Priority 5), Priority_6(Priority 6), Priority_7(Priority 7), Priority_8(Priority 8), Priority_9(Priority 9), Priority_10(Priority 10), Priority_11(Priority 11), Priority_12(Priority 12), Priority_13(Priority 13), Priority_14(Priority 14), Priority_15(Priority 15), Priority_16(Priority 16)
Unit: None
Actual Value Range: Priority_0, Priority_1, Priority_2, Priority_3, Priority_4, Priority_5, Priority_6, Priority_7, Priority_8, Priority_9, Priority_10, Priority_11, Priority_12, Priority_13, Priority_14, Priority_15, Priority_16
Default Value: Priority_2(Priority 2)
GlobalProcSwitch
UtranLoadTransChan
MOD GLOBALPROCSWITCH
LST GLOBALPROCSWITCH
None
None
Meaning: Indicates the UMTS load transmission channel. The BASED_ON_ECO function is temporarily unavailable.
GUI Value Range: NULL, BASED_ON_RIM, BASED_ON_ECO
Unit: None
Actual Value Range: NULL, BASED_ON_RIM, BASED_ON_ECO
Default Value: NULL
CSFallBackHo
CsfbProtectionTimer
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001033 / TDLOFD-001033
CS Fallback to UTRAN
Meaning: Indicates the timer governing the period in which only CSFB can be performed . After the timer expires, the eNodeB performs a blind redirection for the UE.
GUI Value Range: 1~10
Unit: s
Actual Value Range: 1~10
Default Value: 4
UtranExternalCell
Rac
ADD UTRANEXTERNALCELL
MOD UTRANEXTERNALCELL
LST UTRANEXTERNALCELL
LOFD-001019 / TDLOFD-001019
PS Inter-RAT Mobility between E-UTRAN and UTRAN
Meaning: Indicates the routing area code.
GUI Value Range: 0~255
Unit: None
Actual Value Range: 0~255
Default Value: 0
CSFallBackBlindHoCfg
CnOperatorId
LST CSFALLBACKBLINDHOCFG
MOD CSFALLBACKBLINDHOCFG
None
None
Meaning: Indicates the index of the operator.
GUI Value Range: 0~5
Unit: None
Actual Value Range: 0~5
Default Value: None
CSFallBackBlindHoCfg
UtranLcsCap
MOD CSFALLBACKBLINDHOCFG
LST CSFALLBACKBLINDHOCFG
LOFD-001033 / TDLOFD-001033
CS Fallback to UTRAN
Meaning: Indicates the LCS capability of the UTRAN. If this parameter is set to ON, the UTRAN supports LCS. If this parameter is set to OFF, the UTRAN does not support LCS.
GUI Value Range: OFF(Off), ON(On)
Unit: None
Actual Value Range: OFF, ON
Default Value: OFF(Off)
GeranExternalCell
Rac
ADD GERANEXTERNALCELL
MOD GERANEXTERNALCELL
LST GERANEXTERNALCELL
LOFD-001020 / TDLOFD-001020
PS Inter-RAT Mobility between E-UTRAN and GERAN
Meaning: Indicates the routing area code.
GUI Value Range: 0~255
Unit: None
Actual Value Range: 0~255
Default Value: 0
GeranNcell
BlindHoPriority
ADD GERANNCELL
MOD GERANNCELL
LST GERANNCELL
LBFD-002018 / TDLBFD-002018
Mobility Management
Meaning: Indicates the priority of the neighboring cell during blind handovers. Blind handover is a process in which the eNodeB instructs a UE to hand over to a specified neighboring cell. There are 32 priorities altogether. The priority has a positive correlation with the value of this parameter. Note that the value 0 indicates that blind handovers to the neighboring cell are not allowed.
GUI Value Range: 0~32
Unit: None
Actual Value Range: 0~32
Default Value: 0
CSFallBackBlindHoCfg
GeranLcsCap
MOD CSFALLBACKBLINDHOCFG
LST CSFALLBACKBLINDHOCFG
LOFD-001034 / TDLOFD-001034
CS Fallback to GERAN
Meaning: Indicates the LCS capability of the GERAN. If this parameter is set to ON, the GERAN supports LCS. If this parameter is set to OFF, the GERAN does not support LCS.
GUI Value Range: OFF(Off), ON(On)
Unit: None
Actual Value Range: OFF, ON
Default Value: OFF(Off)
S1Interface
MmeRelease
ADD S1INTERFACE
MOD S1INTERFACE
DSP S1INTERFACE
/ TDLBFD-00300101
/ TDLBFD-00300102
/ TDLBFD-00300103
TDLOFD-001018
Star Topology
Chain Topology
Tree Topology
S1-flex
Meaning: Indicates the compliance protocol release of the MME to which the eNodeB is connected through the S1 interface. The eNodeB sends S1 messages complying with the protocol release specified by this parameter. The value of this parameter must be the same as the MME-complied protocol release. If the parameter value is different from the MME-complied protocol release, the way in which the MME handles these message is subject to the MME implementation.
GUI Value Range: Release_R8(Release 8), Release_R9(Release 9), Release_R10(Release 10)
Unit: None
Actual Value Range: Release_R8, Release_R9, Release_R10
Default Value: Release_R8(Release 8)
UtranNFreq
PsPriority
ADD UTRANNFREQ
MOD UTRANNFREQ
LST UTRANNFREQ
LOFD-001019 / TDLOFD-001019
PS Inter-RAT Mobility between E-UTRAN and UTRAN
Meaning: Indicates the priority for the neighboring UTRAN frequency to carry PS services. In coverage-based inter-RAT PS handovers, if UtranFreqLayerMeasSwitch is turned on, the eNodeB determines the UTRAN frequency to be delivered to a UE based on PS service priorities. The eNodeB delivers the UTRAN frequency with the highest PS priority to the UE by default.In blind handovers to UTRAN, the target cell for a blind handover is selected based on PS service priorities. The cell on the UTRAN frequency with the highest PS priority is selected by default.When this parameter is set to Priority_0 for a UTRAN frequency, the UTRAN frequency is not included in PS service priority arrangement.
GUI Value Range: Priority_0(Priority 0), Priority_1(Priority 1), Priority_2(Priority 2), Priority_3(Priority 3), Priority_4(Priority 4), Priority_5(Priority 5), Priority_6(Priority 6), Priority_7(Priority 7), Priority_8(Priority 8), Priority_9(Priority 9), Priority_10(Priority 10), Priority_11(Priority 11), Priority_12(Priority 12), Priority_13(Priority 13), Priority_14(Priority 14), Priority_15(Priority 15), Priority_16(Priority 16)
Unit: None
Actual Value Range: Priority_0, Priority_1, Priority_2, Priority_3, Priority_4, Priority_5, Priority_6, Priority_7, Priority_8, Priority_9, Priority_10, Priority_11, Priority_12, Priority_13, Priority_14, Priority_15, Priority_16
Default Value: Priority_2(Priority 2)
CSFallBackHo
CsfbHoCdmaB1ThdPs
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001035
CS Fallback to CDMA2000 1xRTT
Meaning: Indicates the pilot strength threshold related to event B1, which is used in CS fallback to CDMA2000. A UE sends a measurement report related to event B1 to the eNodeB when the pilot strength in at least one CDMA2000 cell exceeds this threshold and other triggering conditions are met. For details, see 3GPP TS 36.331.
GUI Value Range: -63~0
Unit: 0.5dB
Actual Value Range: -31.5~0, step:0.5
Default Value: -34
CSFallBackHo
CsfbHoCdmaTimeToTrig
MOD CSFALLBACKHO
LST CSFALLBACKHO
LOFD-001035
CS Fallback to CDMA2000 1xRTT
Meaning: Indicates the time-to-trigger for event B1, which is used in CS fallback to CDMA2000. When CS fallback to CDMA2000 is applicable, this parameter is set for UEs and used in the evaluation of whether to trigger event B1. When detecting that the signal quality in at least one CDMA2000 cell meets the entering condition, the UE does not send a measurement report to the eNodeB immediately. Instead, the UE sends a report only when the signal quality continuously meets the entering condition during the time-to-trigger. This parameter helps reduce the number of occasionally triggered event reports, the average number of handovers, and the number of wrong handovers, and hence helps prevent unnecessary handovers. For details, see 3GPP TS 36.331.
GUI Value Range: 0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms, 1280ms, 2560ms, 5120ms
Unit: ms
Actual Value Range: 0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms, 1280ms, 2560ms, 5120ms
Default Value: 40ms
CSFallBackHo
LocalCellId
LST CSFALLBACKHO
MOD CSFALLBACKHO
LBFD-001001 / TDLBFD-001001
3GPP R8 Specifications
Meaning: Indicates the local ID of the cell. It uniquely identifies a cell within a BS.
GUI Value Range: 0~17
Unit: None
Actual Value Range: 0~17
Default Value: None

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