Missed call when mobile attached on 3G

[ninjafine]

Directed retry could be the cause if the settings is very aggressive. Imagine subscriber A calls to B saying "call me back" or something ending call in 2G due DR. B make an attempt to call but A is not reachable. One of the solution is to have common LAC in 2 and 3G.

[rsv12]

Hi,
Check Open Loop Power Control parameters. Sometimes it could be the reason for missed calls. Do you know how many rach messages usually should be send in your network before UE get the answer from NodeB?

[elkador]

Have you verified if complaints where coming from customers owning the same type of UE? This problem can be UE-driven as well...

[sekit]

Try to set treselection parameter on 1s. It's e******* parameter.

[Spider]

Back again, actually this problem was not related to some UE, from our analysis we deduced that it could be related to some paging messages discarded on RAN Level for some capacity issues, can anyone tell me what is the maximum capacity for one Node B regarding how many paging/s could be handled?

[elkador]

Usually Paging congestion will appear per LAC. Paging Load should be less than 60%.
If not the case, then you will need to trace a missed call in the RNC and MSS. Likely a bug fix, your vendor is likely to help on this matter...

[acronopio]

Hello:

Did you solved your issue ? , we faced a similar problem here with similar CS Paging Success Rates in fact I noticed from your post that 91% is actualy a low value we had missing calls issue under 96% .

We did a long investigation and we found out that the PS Paging was so huge that was filling up the paging channels in radio so there was no room for CS Paging ( may be that´s why you see paging coming out but there is no answer in our case that paging message was not reaching the user at all)

The main reason behind this was the use of Smartphones with Fast Dormancy Features that takes them into idle very quickly creating this huge PS Paging situation. Bottom line we took all the Iphones into private ip addresses ( and NAT of course) , this reduced the PS Paging and increased the CS Paging Success Rate and now there are no more missing calls

hope this helps
BR

[Spider]

Hi Acronopio, thank you for your reply actually i changed work on another network! where we face low paging SR and high MP load on RNC due to signaling for paging and fast dormancy of mobiles, but i didn't understand well the solution that you did, can you give me more details on your methodology!

Reputation already given

[acronopio]

Hi Acronopio, thank you for your reply actually i changed work on another network! where we face low paging SR and high MP load on RNC due to signaling for paging and fast dormancy of mobiles, but i didn't understand well the solution that you did, can you give me more details on your methodology!

Reputation already given

Hello Spider :

The Paging is caused by incoming traffic when the UEs are idle , meaning that if a lot of Smartphones are using Fast Dormancy and some traffic is coming in from the Internet it will create huge PS Paging traffic . In our case this situation congested the paging channels leaving no room for CS Paging and creating a Low Succes Rate for CS Paging ...our solution was simple , to avoid this incoming traffic ,how ? moving all the smartphones to private ip addressing in the GGSNs ( in the PS Core ) , so there is no way that incoming unsolicited traffic comes in. This solution requires a NAT device at the network edge (may be a Cisco Router or a Firewall in the Internet access from the operator).

We really solved the issue with this set up , and now the CS Paging success is high and there are no more missing calls anymore !

The thing here is that there is a lot of unsolicited traffic coming in from Internet ( just like in your internet router in your house) , everytime you see people trying to reach the UEs , and the UEs don´t answer most of the time but this situation will trigger paging ( to find the Smartphone that is Idle)

When you define private ip addressing for the Smatphones only solicited traffic ( meaning traffic that the Smartphone was requesting for) is allowed to get in

hope this helps

BR
Alexi

[Spider]

Thanks a lot, i'll try to discuss this with PS core guys