Number called B not responding the first time, only on second dialing

3G / 2G
,
21

No it’s not related to CSFB.

Cell phones which are not supporting 4G are also facing the same.

22

As you are saying, this problem is in the whole 3G network, than I guess best possible way would be to take IU trace or even call trace.

You will be get the clear picture where actually the rejection is happening and why.

23

Thanks!

How about if we implement Seamless Paging feature?

EXTD_LAC_PAGING_SWITCH

Do you think we can give it a try?

24

It’s always better to identify the problem and solve it rather than suppress it.

25

These numbers are huge!

Using the same counter, query at least 2 weeks of data, day level.

Check the trend in this counter, and check which date the problem started.

Follow below steps for remedy:

  1. Check the operations log, so see if there are changes on big scale.
  2. Do a trace, as the experts say, it’s always to know the issue rather than suppress it.
  3. Check if the sites having this issue in the same area, if yes check with the Core team about LAC/TAC mapping, or LAC definition in the MSC/Core.
  4. Check the other channels in the 3G, you’re checking the PCH, check if the NW started pushing users to PCH channel instead of the FACH. Check if the S-CCPCH is working properly.
  5. Again, check if the paging timers have been changed, from the operation logs, better check with the Core team.

This is for know to have an idea about the problem.

26

If it’s the problem with the whole network then it’s more likely to be a Transmission or Core issue.

Sudden change in the entire radio network is unlikely.

Get the Core team involved, initiate a call trace and verify the LAC and RAC definition and check the failure reason.

27

I’ve seen it once and the problem was in OpenLoop Power Control for ULPC. Mobile sometimes didn’t build enough power to reach BTS, so it was a noticed problem that did not show at KPIs.

Check on UL open loop PC parameters for inconsistences. K parameter, power increment and Max probes.

MSC counter on not completed calls should show you a ruge difference if that is the case.

It should be Rel19 on Ericsson Axe.

28

I experienced this problem on my network and it was a CSFB problem and lack of eUTRAN neighbors.