•A bis failure
•Path unbalance between DL/UL caused by difference in sensitivity between BTS & MS. (MS- 102dbm, BTS-104 dbm)
•Co-BCCH Frequency and BSIC in the nearby BTS Cells in a Coverage area.
•SDCCH defined on TRX having poor path loss.
•High Interference level.
•High SD congestion.
•Greater Rx level access min.
•Due to heavy location updates on the cell.
•Hardware Issues.
to Reduce the SD drop we have to concentrate on the above