FDD-LTE network, there some TAU reject during use Apple UE test CSFB
function in some eNodeB,need to check the failure and solved.The Apple
UE test log as following:
-> UE releases the call in UMTS
-> moves to LTE
-> Sends TAU
-> Gets TAU Accept
-> The Next TAU is rejected with cause 10
Setp20 signal explain:
The MME sends a TAU Accept (GUTI, TAI list, EPS bearer status, NAS sequence number, NAS-MAC, IMS Voice over PS session supported Indication) message to the UE. If the active flag is set the MME may provide the eNodeB with Handover Restriction List. GUTI is included if the MME allocates a new GUTI. If the "active flag" is set in the TAU Request message the user plane setup procedure can be activated in conjunction with the TAU Accept message.
According the above TAU update signaling, UE call end and move to LTE network, the normal TAU update process should be like this: UE send TAU Request to SGSN, SGSN feedback TAU Accept, after UE send NAS signaling TAU Complete, it’s meaning the TAU procedure is finish.But check the Apple UE test log, while The SGSN feedback TAU Accept, does not contain GUTI information, lead to no complete message from UE, shown as The Next TAU is rejected with cause10.
If the MME locally deactivates EPS bearer contexts for the UE (see subclause 22.214.171.124.4) and no active EPS bearer contexts remain for the UE, the MME shall send the TRACKING AREA UPDATE REJECT message including the EMM cause value #10 "Implicitly detached".
After TAU rejected the UE action: