Downlink DTX support
This is not as important as uplink DTX, but helps with reducing interference toward surrounding cells on same/adjacent ARFCN
#6 Updated by laforge about 2 years ago
- Priority changed from Low to Normal
In Downlink DTX, the BTS is muting some bursts/blocks during times with no voice activity in the downlink side towards the phone. This basically means that there are RTP SID frames (possibly at larger-than-20ms-intervals), which should trigger the muting of some bursts from the BTS.So basically
- if we are on a secondary TRX (not TRX0 which carries the BCCH), and
- if DTXd is active, and
- we get a PH-RTS.ind from the PHY for the TCH (not SACCH!), but we do not have a valid codec frame with actual voice data (but rather no codec frame or a SID frame), then we chose to mute the transceiver for this burst, rather than sending a normal/dummy burst.
In terms of measurement reporting, the phone will perform the downlink rxqual and rxlev calculations for both FULL (all frames) and SUB (only sacch frames) and report this to the BTS, who will forward it in the RSL MEAS REP to the BSC. The BTS does not need to perform any processing here, as far as I know.