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RRC connection Failure

LEMAURE - 10th December 2017  (23:10 GMT)

durng csfb the paging is sent on 4G and the UE responds rhrough an RRCconnReq with the cause extended service
the paging response occurs through the 3G network after the release (blind or assisted). at the end of the call if there is "fast return to 4G" feature activated, the UE immediately return of 4G otherwise, LAC update occurs on 3G network

MUSTAPHA EL AHMADI - 6th November 2017  (08:56 GMT)

Thanks a lot for your answer.
I have another question in the same subject:
Can the CSFB be an issue for MTC Call Attempt failure and paging ,when the UE came back to 3G?paging sent when he was in 3G par exemple?because from the drive tests before a paging,the previous message was CSFB.
Thanks for your support

pix - 6th November 2017  (06:16 GMT)


Well, I would just attempt a MOC and see how it goes. If MOC is made, then it means the UE is attached and capable of doing voice calls (through VOLTE I assume ?).

Try to do the MTC after that.

If MOC is not possible, then you know for sure there's an issue. I would investigate the ATTACH procedure (which you can trace by doing an "airplane" mode ON/OFF during the tracing)

Also, try to do packet transfers. If those are possible but not the VOLTE, then it's something else altogether.


MUSTAPHA EL AHMADI - 5th November 2017  (12:18 GMT)

Thanks for your reply
I agree with you and I checked M-TMSI in a previous messages before paging like RRC connection req(MOC) or tracking area update and the M-TMSI in a a paging didn't match any one nor in RRC request or tracking area update .The cause is B-party is unreachable,it's look like the device is down,or not connected but I don't know how to confirm ,prove that

pix - 4th November 2017  (12:34 GMT)


Are you certain the Paging was intended for your UE ? I find it strange that the UE does not proceed with a RRC Connection.
Did the UE properly attach to the network ? Performed Tracking Area Updates ? What about MOC ?


MUSTAPHA EL AHMADI - 4th November 2017  (11:03 GMT)

I need your support on how to troubleshoot on high MTC call attempt on 4G,during a drive test as I can see paging received,nothing happened after this message(no rrc connection request,...),radio condition ok ,except of 3 failures dur to SNR =-6
what can be the cause?the mobility can impact the MTC call attempt failure due to delay paging?

pix - 7th June 2017  (21:09 GMT)


What a vague question. Are you able to elaborate ?

br / pix

Sarin Sreevalsan - 5th June 2017  (04:29 GMT)

I'm getting a high RRC failure rate in my network . Kindly let me know how i can tackle this issue pls.

VIKAS - 1st December 2016  (19:13 GMT)

There is RRC failure in Cell due to cause code RRCsig.RRcsetup time expires before signal reach to UE.Please support to resolve.

GJ Rajput - 4th November 2016  (06:43 GMT)

Failure Reasons in RRC:
1. Coverage Issue
2. Interference Issue
3. PRACH Usage High
4. Configuration Issue
5. Paging Load High

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Last modified: 17 May 2017

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