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ahmadia
2010-05-17, 08:36 PM
Dear RNO engineers ;

we have a live 3G network upgraded from a 2G network , but we do have a problem of pushing our subscriber to the new network.

I have invistigated the probability of the UE cabability ... I found there are lots of UE support the 3G but yet they are still camping on the 2G network

paboya
2010-05-17, 08:53 PM
U can check parameter at 2G and 3G
if i dont make a mistake, any parameter that correlated with
priority connection.. which 3G to be priority..

May i know what is ur vendor ??
I use NSN..

rayhan
2010-05-17, 11:47 PM
Hi Dear,
Apart from Network settings there are lot other factors which may impact UE <Handset> registration on any Network.

1. USIM Used : What kind of USIM your operator is using is it USIM or rel 99 USIM, USIMs play an important role in HPLMN and RAT can be defined in them. This means USIM can force device to look for specific HPLMN with RAT preference. <Could be 2G or 3G>

2. Device's RAT Preference :This could be equally important as this defined the RAT preference of the device. If it is set to 2G then device will always look for 2G network and then based on Network selection parameters it could reselect 3G networks.

Apart form this please have a look into cell selection and re-selection parameter set in your network. Look for SIB 3.

What is the value of Ssearch RAT, is it set to 0 <Recommended>, and do check other thresholds....

Hope this information may be useful to you .....

cocoloco
2010-05-19, 11:46 PM
Hi all,

I have a doubt associated to this issue. The problem is that there are several mobiles of 2 differents models in the same place (same RF condition, same network operator) that hand over from 3G to 2G at the same time. After a few seconds phones of one of the models change to 3G again but the others continue attached to 2G for a long time until they reselected a 3G cell. I ´ve checked reports and both measures the same neigborh 3G cells but not the same values : one of them reports RSCP -120 dBm continuosly and the other one reports much better conditions.

Have you any idea or experience about it? Thanks a lot

rayhan
2010-05-20, 01:03 AM
This is quite normal scenario... ....just like all fingers <of you hand> are not equal ..in the same way RX sensitivity of the handsets differs from each other.... as well...few handsets could have poor receiver sensitivity ....you can refer SAR reports or Antenna reports of these devices for better understanding.

apart from this it too depends upon power class of the handset ....

Like generally in UMIS Handset power Class is 4 <<+21 : +2/-2 dB>> or 3 <+21 : +3/-1 dB>
depending upon frequency bands ...

GSM : This could be Class 4 <GSM 850/ 900> or Class 1 <GSM 1800/1900>

In you case the handset which reselected to 2G must have poor antenna sensitivity ....as in SIB 3 QrxLevMin is set to -119. This means handset can only select 2Gwhen its CPICH - RSCP is >> then -120dB. Other handset which is sill camped on 3G has better antenna sensitivity.
Same is the case with Handover ......apart from this what is the value of Ssearch RAT ...if you can share SIB 3, SIB 11 , 2Qter I can provide more information on this ....

cocoloco
2010-05-20, 08:03 PM
This is quite normal scenario... ....just like all fingers <of you hand> are not equal ..in the same way RX sensitivity of the handsets differs from each other.... as well...few handsets could have poor receiver sensitivity ....you can refer SAR reports or Antenna reports of these devices for better understanding.

apart from this it too depends upon power class of the handset ....

Like generally in UMIS Handset power Class is 4 <<+21 : +2/-2 dB>> or 3 <+21 : +3/-1 dB>
depending upon frequency bands ...

GSM : This could be Class 4 <GSM 850/ 900> or Class 1 <GSM 1800/1900>

In you case the handset which reselected to 2G must have poor antenna sensitivity ....as in SIB 3 QrxLevMin is set to -119. This means handset can only select 2Gwhen its CPICH - RSCP is >> then -120dB. Other handset which is sill camped on 3G has better antenna sensitivity.
Same is the case with Handover ......apart from this what is the value of Ssearch RAT ...if you can share SIB 3, SIB 11 , 2Qter I can provide more information on this ....

Thanks a lot for your answer. However, i´ve not found the reason. As you said, QrxLevMin is set to -119. In SIB 3 Ssearch RAT is 0.0dB and obviously this is common for both handsets. I think its relationated to antenna sensitivity as you said, but i´ve not found any data about it.

rayhan
2010-05-20, 09:10 PM
place two handsets <from different vendors> under same radio conditions <good condition> and check for the reported CPICH RSCP ...you may see diff of 2-3 dB or more ....which could play important role at cell boundary...means unit with poor antenna sensitivity will have low 3G coverage and hence will reselect to 2G soon compared to the other one which is still camped on 3G due to better receiver sensitivity.