SYSTEM AND METHOD OF MINIMIZING THE NUMBER OF VOICE TRANSCODINGS DURING A CONFERENCE CALL IN A PACKET-SWITCHED NETWORK

摘要

A system, method and access gateway for minimizing the number of transcodings of a speech signal during a Voice-over-IP (VoIP) conference call in a packet-switched network in which Tandem Free Operation (TFO) is utilized. The system includes a first gateway (14) connecting the first mobile subscriber (11) to the network, a second gateway (25) connecting the second subscriber (23), and a third gateway (22) connecting the third subscriber (19). The second gateway sends a message (62) to the first gateway indicating a speech coding mode being utilized between the second gateway and the second subscriber. The third gateway sends a message to the first gateway indicating a speech coding mode being utilized between the third gateway and the third subscriber. When a three-way conference call (64) is initiated, the first gateway (14) encodes the call path (56) to the second subscriber with the speech coding mode (53) being utilized between the second gateway and the second subscriber. The first gateway also encodes the speech signal for the call leg (55) to the third subscriber with the speech coding mode being utilized between the third gateway and the third subscriber.