The T3101 is supervising the paging retransission. I can’t find a correlation between SDR and PSR, but please correct me if i’m wrong.
First thing to do is to find the cause of SDR. Timing Advance ? Bad Quality ? Bad Level ?
Activate the SDCCH HO. Doing so will give you precise counter regarding SDCCH HO CAUSE, which will help you diagnose the main issue.
Put 2 SDCCH on the TRX0 (bcch) only.
Then put 1 SDCCH on the TRX1, and 1 SDCCH on BCCH TS.
Then compare SDR between those two configuration.
If available, check the SDR per TRX.
Check the path imbalance.
Check the VSWR.
Also, the cells may be located at a MSC border ? I’m not familiar with this issue, but if you do a drivetest, you may be able to see things more clearly : call setup can’t go through when the MS has just changed MSC area. (to be verified)