Measurement Counter
A9206: UP_EGPRS_TBF_ABNORM_REL_N3101_OVERFLOW
Description
This measurement provides the number of uplink EGPRS TBF abnormal releases due to N3101 overflow in a granularity period. Together with Number of Successful Uplink EGPRS TBF Establishments, this measurement indicates the call drop rate of the uplink EGPRS TBF in a granularity period. A high measurement value is yielded because the radio quality of the cell is bad.
Unit
Integer number or integer.
Measurement Point
During the uplink transmission, the BSC reserves uplink blocks for the MS and assigns valid USF to schedule these uplink blocks. In addition, the BSC attaches the USF message to the downlink blocks that the MS listens to. The purpose is to instruct the MS to upload data on the corresponding uplink blocks. If the BSC receives valid uplink blocks in the blocks reserved for the MS within a certain period predefined by the BSC timer, the N3101 is reset. Otherwise, the N3101 is incremented by one, and the BSC reschedules the uplink blocks for the MS through the POLLING REQUEST message. If the N3101 overflows, the BSC releases the uplink EGPRS TBF.
Figure 1 shows the procedure of abnormal release of the TBF due to no response from the MS. Each time the N3101 overflows (see measurement point A), the counter is incremented by one.
Formula
This is an original counter without involving any formula.