Inputs to help with TBF dropping for GSM.
– Make sure no Hardware problem especially related TRX module. You need to fix Hardware issue first if you found hardware problem
– Make sure no Interference. You have to do re-tune or change frequency that suspected Frequency Interference to improve TBF drop rate
– Make sure No overshooting Cells. You can adjust Antenna Tilt/Down tilt for overshooting cells to improve TBF drop rate and avoid access traffic in low RX level thus can improve TBF drop call.
– Reduce Dynamic PDCH(MAXPDCHRATE) and add static PDTCH to avoid preemption channel by voice services especially for cells with high Voice traffic.
-Shifting Static PDCH from TRX non BCCH to TRX BCCH and make priority setting by set TRX layering priority which can be set by OPTL value in GTRXDEV object.With this strategy data services will be concentrated in TRX BCCH with full power(no power control) thus can improve TBF drop rate and getting better than data services in TRX non BCCH.