Measurement Counter
A9102:DOWN_GPRS_TBF_ESTB_SUCC
Description
This measurement provides the number of successful downlink GPRS TBF establishments in a granularity period. A low measurement value indicates that the radio environment, network parameter configuration, network resource configuration, or network equipment is not satisfactory, and thus requires optimization. Further analysis should be made based on the causes of GPRS TBF abnormal release. Together with Number of Downlink GPRS TBF Establishment Attempts, this measurement indicates the downlink assignment success rate in a granularity period. Together with the number of downlink GPRS TBF abnormal releases, this measurement indicates the call drop rate of the downlink GPRS TBF in a granularity period.
Unit
Integer number or integer.
Measurement Point
Successful downlink GPRS TBF establishment on the CCCH
The BSC initiates the request for downlink GPRS TBF establishment by sending the IMMEDIATE ASSIGNMENT message with Starting Time on the CCCH. When Starting Time expires, the BSC sends the POLLING message to the MS to obtain the TA value. The BSC also reserves the block resource for the MS to respond with the assignment acknowledgement message. If the BSC receives the PACKET CONTROL ACKNOWLEDGEMENT message from the MS on the reserved block resources, it indicates that the downlink GPRS TBF establishment is successful. On the basis of received PACKET CONTROL ACKNOWLEDGEMENT message, the BSC can calculate the TA value. Figure 1 shows the procedure of downlink GPRS TBF establishment on the CCCH. Each time the BSC receives a PACKET CONTROL ACKNOWLEDGEMENT message (see measurement point B), the counter is incremented by one.
Figure 1 Downlink packet immediate assignment
Successful downlink GPRS TBF establishment on the PACCH
The BSC can initiate the downlink GPRS TBF establishment procedure by sending the PACKET DOWNLINK ASSIGNMENT message on the uplink or downlink PACCH to the MS. The BSC also reserves the blocks for the MS to respond with the assignment acknowledgement message. If the BSC receives the PACKET CONTROL ACKNOWLEDGEMENT message from the MS on the reserved block resources, it indicates that the downlink GPRS TBF establishment is successful. Figure 2 shows the procedure of downlink GPRS TBF establishment on the PACCH. Each time the BSC receives a PACKET CONTROL ACKNOWLEDGEMENT message as a response to the PACKET DOWNLINK ASSIGNMENT (see measurement point A), the counter is incremented by one.
Figure 2 Downlink assignment on the PACCH
Formula
This is an original counter without involving any formula.