SDCCH Drop due to other (Ericsson)

Hello Experts,

I have a problem with SDCCH drop in a single cell reached 17% ( where the other sectors in the same site have no problems)and the reasons are 99% other reasons,the cell has 2 TRXs I tried to halt on and TRX and work with the other TRX carrying the BCCH and the SDCCH but I did not get any improvement (vise verse).
so How I can find out the solution for this problem????

please help me ^_^

Thank you all,,,