Causes for Radio Connection With UE lost and Release to generated UTRAN Reason

[Spider]

Hi Guys,

This is my first post here and hope to have some findings for my question. Actually, i'm working on IUCS traces and got several times the reasons 'Radio connection with UE lost' and 'Release to generated UTRAN Reason' for many cases OC/TC calls setup failure , call drops.

I assume that these are radio failures, any suggestion for fine troubleshooting? What could be the exact cases?

Thanks in advance.

[jayk]

"Radio connection with UE lost" occurs due to Radio Interface exceptions, generally it is due to coverage/pilot pollution issues. Need to check Radio conditions.

"Release due to UTRAN Generated Reason" is initiated by RNC due to UTRAN Reasons. Need to check traces step by step.

[Spider]

I'll take a look on the most affected cells and keep you informed.

[Spider]

From Iub trace analysis i remark that the cell condition is good in terms of RSCP and EC/No, but, the last message consolidated with the RADIOCONWITHUElost and RELEASEDUETOGENERATED is synchronization failure, sent from the node B to RNC, in some cases the UL SIR target increase in the end and we get this causes.

Any suggestions of what could be behind the synchronization failure and involved parameters?

[jmasterfunk]

Is this RAN12? Are you also seeing that the UE is covered very well by one cell? I have seen this in some of our rural sites. A device on a cell with very light load, very good RSCP and Ec/No. Huawei has not been able to provide and explanation.

[Spider]

It's E******* RAN, until now i'm trying to get more details, any ideas?

[agenov]

Check RTWP, the range of the serving, alarms in the nodeb etc...
Try collect more details from IMSI/Cell trace.

It's E******* RAN, until now i'm trying to get more details, any ideas?

[auto_art]

i think u shuold read Radio connection supervision algoritham..! that can answer your queries.

Hi Guys,

This is my first post here and hope to have some findings for my question. Actually, i'm working on IUCS traces and got several times the reasons 'Radio connection with UE lost' and 'Release to generated UTRAN Reason' for many cases OC/TC calls setup failure , call drops.

I assume that these are radio failures, any suggestion for fine troubleshooting? What could be the exact cases?

Thanks in advance.

[adewijaya]

in case of your statement : "in some cases the UL SIR target increase in the end and we get this causes" its mean could be by internal uplink load (like : capacity) or eksternal uplink interferensi with other frequency, please make sure with this two kind of RTWP

[topoffenders]

check the event sequence:
and look for this event:

(RRC) UL-DCCH-MessageType (failureCause=FailureCauseWithProtErr)