1. How to improve TBF Drop?
There are several ways you can work for TBF Drop. Check frequency in BBH and there
transmission rate in those cells. if high retransmission --> for sure there is problem on
Frequency. Improve C/I (reduce interference) Try use most BCCH TRX TS for PDCH
Make sure (E)GPRS link adaptation is enabled. If frequency change doesn't get good
result limit the(E)GPRS coding scheme up to MCS7 instead of MCS9. MCS7 is more
robust than MCS9Reduce no. of users per PDCH Check PCU congestion/Utilization
YoucancalculatetheaveragenumberofsimultaneousTBFsperPDCHbyusingtheratios:TBFP
DLGPRS/PDCHDLGPRSandTBFPULGPRS/PDCHULGPRSrespectivelyforDLandUL.
ThesecountersarefoundundertheobjecttypeTRAFFGPRS.IfthenumberofusersperPDCHish
igh,thenthethroughputperuserwillbelow.YoushouldconsideraddingmorePDCHsiftheabove
ratiosarehigh.ThereareseveralwaysyoucanworkforTBFDrop.1)CheckfrequencyinBBHand
theretransmissionrateinthosecells.ifhighretransmission--
>forsurethereisproblemonFrequency.ImproveC/I(reduceinterference)2)TryusemostBCCH
TRXTSforPDCH3)Makesure(E)GPRSlinkadaptationisenabled.4)Iffrequencychangedoesn
'tgetgoodresultlimitthe(E)GPRScodingschemeuptoMCS7insteadofMCS9.MCS7ismorero
bustthanMCS95)Reduceno.ofusersperPDCH6)CheckPCUcongestion/Utilization***GSM
RFOptimizationGuide*****************