G.7 Intra BSC TFO Handover (TRAU remains)

28.0623GPPInband Tandem Free Operation (TFO) of speech codecsService descriptionStage 3TS

G.7.1 TRAU-TC TFO connection

The following protocol flow shows a local handover in a TRAU-TC TFO connection, where the local TRAU remains the same. The distant TC sees potentially some phase alignment of the TFO Frames, but no interruption of the TFO Operation. The Round Trip Delay is not important for TC and RNC and is therefore not measured. The local BTS estimates the round trip delay when it receives the first Con_Ack.

Figure G.7.1-1: Intra BSC TFO Handover – TRAU-TC TFO connection

G.7.2 TRAU-TRAU TFO connection

The following protocol flow re-shows the lower part of a local handover in a TRAU-TRAU TFO connection, where the local TRAU remains the same. The Round Trip Delay is important for both BTSs and therefore the Handover_Complete Message triggers a new delay measurement within the distant BTS.

Figure G.7.2-1: Intra BSC TFO Handover – TRAU-TRAU TFO connection