L9557: CELL_LLC_TX_DOWN_EGPRS_BKGND_LLC_PDU_TRANS_DURATION
This measurement provides the transmission duration of all downlink EGPRS background services in a cell in a granularity period.
ms.
Each time the transmission of the background service is complete on the downlink EGPRS TBF, the transmission duration is taken as the transmission duration of the downlink EGPRS TBF background service. In a granularity period, the sum of the transmission duration of all background services on the downlink EGPRS TBFs is taken as the total transmission duration of downlink EGPRS background service.
This is an original counter without involving any formula.