IRAT HO Problem Alcatel (3G) to Alcatel (2G)

[srm057]

Hi all,

We are facing High IRAT Prep Failures (10-15%) on 1 RNC (isolated from other 3G network). IRAT HOs are THE only option for this RNC. The issue is sporadically present on half of the SAIs. These cells are not changing everyday too.

I got LAC and database definition checked. I am getting the cause No Resouce Available but there is no congestion on target cell at all.

Iu-trace is showing that there is high number of IRAT HO failure during some of calls not all calls are affected. Someone discussed something related to ciphering and speech codec but I was not been able to grasp it. Please help..

The RNC is using AMR 2 AMR-WB codec whereas the target BSC is using EFR and HR codec.