Monday, 9 November 2015

TDD-LTE-How to turn RIM (RAN information manager) function


RIMRAN information managerR9 is a characteristic feature of , 3G side can obtain the configuration of the LTE network in advance, then released when the 3G LTE -side configuration distributed UE, UE avoid searching , decoding overhead message 3G thereby shorten CSFB fall delay . By assessing the existing commercial network , the calling side reduced by an average delay of about 1s. This article covers only the UMTS LTE drop process.


1Parameter modification

Enabling RIM feature requires eNodeB, MME and 3G wireless side modify the parameters , parameters and modify specific methods involved are as follows .
Parameters path
The main parameters involved
system parameters
Defaults values
Recommended configurations 
Wireless Service Configuration - > Mobility Management
UTRAN RIM process switch
Close
Open
Open

The parameters in the network optimization template name and explain :
switchUtranRim
UTRAN RIM process switch
long:0:close,1:open;default:0
UTRAN RIM process switch
R-W-I
1

Meanwhile , RIM feature requires configuration data in UMTS LTE side neighborhood , the general neighborhood amount not more than 16 , due to the presence V3.10.20.30P53 BUG, more than 11 when the eNodeB release message will not be sent , it is recommended to configure 10 neighborhood .
2Core network side
MME section :
 
 SGSN section :

 
3RNC side
In URncFunction table, you need to open UTRA SI function switch .
 
Effect and takes effect confirmed
The following is based on the test data , Zhengzhou , randomly selected twice CSFB process , the first based on R9 (RIM hit ) to redirect the flow , and the second based on the R8 's ordinary redirection process (RIM misses ) , the first drop delay (LTE RRCConnectionRelease-> RRCConnectionSetup) for 389ms, while the second drop latency (LTE RRCConnectionRelease-> RRCConnectionSetup) is 774ms. Therefore , with respect to the success of the first RIM RIM unsuccessful second save 385ms, the effect is significant .
RIM Success:
 Second call : RIM hit failure , take regular R8 processes.
 


Budi Prasetyo

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