E-RAB Failure due to MME Failure

[mounir34]

dear
please any suggestion to improve the E-RAB due to MME failure ,
-the UL Coverage is bad and almost the UE's are near to site about 400m

below are the main causes,

UEM_UECNT_REL_MME_CMD_BEFORE_SEC_MODE_CMP

UEM_UECNT_REL_MME_CMD_BEFORE_UECAP_UECAP_INFO

[samuraial]

m8,

UE context release MME command before secure mode complete
UE Context release MME command before ue capability info

Trace your Uu and S1 interface and see if you can get any user that can give you a clear picture.
Any MME timer changed during this time?

A trace will give you a clear picture.

B/R

[mounir34]

1. UEM_UECNT_REL_MME_CMD_BEFORE_UECAP_UECAP_INFO

UEM_UECNT_REL_MME_CMD_BEFORE_UECAP_UECAP_INFO(UE not received the UE Capability request sent by eNodeB or UE Not sent the Capability Information to eNodeB or eNodeB not received the UE Capability Information sent by UE)
Based on the CHR Signaling Analysis, the eNodeB send the UE Capability enquiry to UE, but UE not replied the UE Capability information to eNodeB cause of a Top UE with poor Uplink Coverage.
s1.JPG

s2.jpg

2.UEM_UECNT_REL_MME_CMD_BEFORE_SEC_MODE_CMPUEM_UECNT_REL_MME_CMD_BEFORE_SEC_MODE_CMP(UEnot received the UE Security Command sent by eNodeB or UE Not sent the SecurityComplete command information to eNodeB or eNodeB not received the UE SecurityComplete Information sent by UE)
Based on the CHR Signaling Analysis, theeNodeB send the RRC_Secur_Mode_cmd to UE, but UE not replied the UE SecurityMode complete info to eNodeB cause of a Top UE with poor Uplink Coverage.
s3.JPG

s4.jpg

m8,

UE context release MME command before secure mode complete
UE Context release MME command before ue capability info

Trace your Uu and S1 interface and see if you can get any user that can give you a clear picture.
Any MME timer changed during this time?

A trace will give you a clear picture.

B/R

[samuraial]

UE could be in underground area that can cause this kind of behavior or could be UE behavior.
You could try to tune interoperability parameters to push those edge UEs in 3G.
I say this because if it is weak UL coverage you need to optimize the HW parameters or check with planning.
SW parameters won't do much here IMO.

B/R

[mounir34]

i checked the distance is near to the site about 400m maybe indoor i dont know ,now the main issue is UL Coverage
any suggestion related to Power control maybe can improve the UL Coverage or other parameters

UE could be in underground area that can cause this kind of behavior or could be UE behavior.
You could try to tune interoperability parameters to push those edge UEs in 3G.
I say this because if it is weak UL coverage you need to optimize the HW parameters or check with planning.
SW parameters won't do much here IMO.

B/R

[samuraial]

Well you can try to change the pa parameter from -3 to 0 and this usually helps with ul coverage.
or you can change the irat thresholds to keep the user in 3G in those areas in order not to have bad KPI and improve also the user experience as last step.

B/R