Lost of sync

[cocoloco]

Hi all,

in 3G, It is known that when there is high BLER in uplink or lost of sync, RNC requests mobile to power up, but my question is how can i see this request? in which message?

Thanks

[tsiz]

Hi all,

in 3G, It is known that when there is high BLER in uplink or lost of sync, RNC requests mobile to power up, but my question is how can i see this request? in which message?

Thanks
Its been quite some time since I saw those messages. Check and see if you can see the SIB message from the node B. This should contain the SIR target that the node B would be requesting the ue to ramp upto.

[kentck86]

Its been quite some time since I saw those messages. Check and see if you can see the SIB message from the node B. This should contain the SIR target that the node B would be requesting the ue to ramp upto.


which SIB message should be refering to? Any idea what is the main cause of High BLER?

[jan74]

Hi all,

in 3G, It is known that when there is high BLER in uplink or lost of sync, RNC requests mobile to power up, but my question is how can i see this request? in which message?

Thanks

Loss of sync can happen for many reasons and sometimes it is simply down to Software. You'll often see it in very weak coverage, particularly in the Uplink. If you have TEMS, you can see the BLER values in the Mode Reports. Its painstaking but you will probably see BLER go to 100%. But this is really just an effect and not a cause. The cause of the sync problem is usually down to rapid decrease in Signal Strength or as I said, Software. To rule out Hardware on the cell, check your RRC Access Failures. If you have fails during the RRC Access phase, this can be Sync related as the UE did not establish Sync within T312. This is of course for the initial call setup phase. If your issue is losing sync in connected phase, there is a seperate T312 timer which we have set to 1sec. You could check how often this has been timed out.

Finally, you could see how many RRC-Re-establishments you have on the cell along with Cell Update messages sent due to radiolink Failures. If you have a lot, there could be a coverage blackspot, overshooting or a HW fault.