TBF Success Rate

TBF Success Rate 

TBF Success rate indicate Success percentage of Data call GPRS in GSM.Temporary Block Flow (TBF) is a physical connection used by the two Radio Resource entities to support the unidirectional transfer of PDUs on packet data physical channels. The TBF is allocated radio resource on one or more PDCHs and comprises a number of RLC/MAC blocks carrying one or more LLC PDU. TBF Success Rate is when during a data session, TBFs are successfully established on UL and DL. PDASR (Packet Data access Success Rate) also called TBF Success rate indicate Success percentage of Data call GPRS in GSM.

PROCESS for Optimization:

Check for PDCH Blocking or TBF Blocking due to No channel
PDCH Blocking indicate insufficient data channel for EDGE/GPRS services.For PDCH Blocking you can check also by counter TBF Blocking due to no channel. If you found TBF Blocking then you need to add Channel allocation for Data or you can add static PDCH channel and finally you need to upgrade TRX if found high PDCH blocking.

Check for TBF fail due to MS no response

TBF fail due to MS no response (UL/DL) occurred on cells due to some reasons such as: Frequency interference, Overshooting Cells or hardware problem. You need to check and clear Frequency interference, overshooting and hardware issue include transmission problem.

check initial step such as: Hardware, Overshooting, Frequency interference to improve all KPI include PDASR(Packet Data Acces Success Rate).

TBF Congestion:

 ·         Check The Static and Dynamic PDCH definition from BSC Configuration data

• ·  If you find Zero Static or Dynamic PDCH, define the same.If PDCH definition is sufficient as per the guidelines, then check whether the TBF requests are high. If requests are high, then we need to define more PDCHs in the cell. But before defining more PDCHs, check whether the Voice Utilization is not high and there is no TCH Congestion in the cell..

·         Check Hardware/TRX alarms; Resolve if find any.

·         Audit for any parameters related discrepancies and define as per standard parameters set.

MS No Response: RF and Environmental Factors:

• Low Coverage Areas (Try to reduce low coverage patches with physical optimization; New sites)

• ·    Interference/ Bad quality/ UL-DL Imbalance;Check the states for TRx on which PDCH is configured can be issue of TRx also; Change TRx if you found random behavior of TRX.