3G drop calls – Downlink Direct Transfer

Hi all,

Hoping I can get some help from you guys. I’m getting a lot of CS drops that all point to the same message in the layer 3. The problem I have is that I dont know how to interpret it. The “drop” message is a DDT message and shows a “Disconnect to Mobile” message that the cause of the drop is Type 41 (temporary Network failure). Can anyone explain a bit more about the message as I dont know if its a RF/Core problem/or a PSTN problem.

Although RSCP levels are quite low (-95ish) the ECIO measurements are well within spec (-11).

Sorry, but I cant cut and paste the L3 messaging, but its sequence is basically:

UL-DCCH Active set update complete
DL-DCCH -Downlink Direct Transfer
DL Call Control Disconnect
UL_DCCH Uplink Direct transfer
UL Call Control release

Dropped call

DL_DCCH Downlink Direct Transfer
DL Call Control Release Complete

Then RRC clearing commences.

Any help appreciated

Ta