Measurement Counter
L9120: DL_GPRS_TOTAL_TBF
Description
This measurement provides the total number of downlink GPRS TBFs in a cell in a granularity period.
Unit
Integer number or integer.
Measurement Point
Every time the BSC establishes a downlink GPRS TBF successfully, the counter is incremented by one. The successful downlink GPRS TBF establishment involves the following conditions: The BSC initiates the request for downlink GPRS TBF establishment by sending an IMMEDIATE ASSIGNMENT message with Starting Time on the CCCH. When Starting Time expires, the BSC sends a 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 a 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 the 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. Every time the BSC receives a PACKET CONTROL ACKNOWLEDGEMENT message (see measurement point A), the counter is incremented by one.
The BSC can initiate the downlink GPRS TBF establishment procedure by sending a PACKET DOWNLINK ASSIGNMENT message on the uplink or downlink PACCH to the MS. The BSC also reserves the block resources for the MS to respond with the assignment acknowledgement message. If the BSC receives a 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. Every 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.
Formula
This is an original counter without involving any formula.