Missed call when mobile attached on 3G

[Spider]

We faced several complaints concerning some subscribers receiving missed call alerts while connected to the network. PSR in 3G is around 91% and we are sending twice the paging based on TMSI with 8s interval. The 3G was newly launched and we need any suggestions about this issue.

Any suggestions for investigation?

[louvre]

Due you have isho enabled if yes then check your setting for cell reselection between WCDMA and GSM.. Most of the likely hood problem is that the mobile is ping - ponging between 3G and 2G this will cause miss call and voice mail problem.. also could you be more specific about vendor. further patch / workaround can be figured out based on vendor.

[Spider]

Thanks for your reply, actually we are with Ericsonn Utran and CN and isho is enabled, could you tell me please what are the parameters to be checked? Another Thing i checked for several cases from IU and A interface tracing that the subscriber was on 3G only.

[kevin_h811]

Hi Spider,

Is this for one NodeB only or a cluster of NodeBs.From there you can compare settings parameters.

Regards//

[Spider]

Hi Kevin,

The problem is that problem is very sporadic and hard to detect, that's why i'm trying to get suggestions for troubleshooting.

Br.

[maahsan]

Try to check if this problem is related to some particular type of handset.

[Spider]

As i said, it's sporadic and not easy to detect and based on some complaints, from Iu traces i detected that the paging was sent withtout response from the mobile, and no activity on 2G side was detected. I'm still investigating... any ideas?

[plannerguy]

Hi

u have to look into timers for cell reselection as cells gets reselected it has do LA updation ..

so mean while u will miss paging..

Regards
Plannerguy

[Moon]

Hi,

If you are pushing all UE in idle mode to 3G, you will end up with high number of UEs going from 3G to 2G (as your 3G layer is "small" than 2G layer), in this case & after disconnecting your calls in 2G you will need to do 2G cell reselection & LU then start measuring 3G cells; during this period of 2G cell reselection, LU (which is taking between 20 to 30 s) your UE will not be reachable. You may need to delay ISHO (EcNo to -14/-16, RSCP to -105) to minise going from 3G to 2G, also check cell reselection & make sure you are not doing Ping Pong betwen 3g to 2G (Qqualmin=-18 dB, SsearchRAT=2dB,FDDQMIN=-14,QSI=7)

Regards

[Spider]

Actually we are implementing Directed retry, to favorize voice call on 2G layer, but i think it couldn't be the cause for this issue?