Systems and methods for echo management in conferencing over a network using multiplexed mixed multicast
A system includes participant nodes that unicast a voice stream to a master node and receive a multicast voice stream from the master node. The multicast voice stream may be a mixed voice stream mixing the voice streams of the participants. In this case, each participant performs echo cancellation on the multicast voice stream. Alternatively, the multicast voice stream may be a multiplexed voice stream multiplexing the voice streams of all participants. In this case, each participant de-multiplexes the multicast voice stream and generates a mixed voice stream that does not include that participant. Alternatively, the multicast voice stream received by each participant may be a multiplexed digital voice stream multiplexing multiple mixed streams including one mixed stream that does not include the voice stream of that participant. In this case, each participant de-multiplexes the multicast voice stream to obtain the mixed stream that does not include that participant.
1. A method of voice over Internet protocol (VoIP) conferencing, comprising:
transmitting, by a participant node, a digital voice stream to a master node over a unicast session;
receiving, by the participant node, a multiplexed digital voice stream from the master node over a multicast session, wherein the multiplexed digital voice stream includes a plurality of mixed digital voice streams, wherein each mixed digital voice stream in the multiplexed digital voice stream is generated by a mixer at the master node and is configured for a corresponding participant of the VoIP conferencing, wherein the plurality of mixed digital voice streams include a mixed digital voice stream that is configured for the participant node, wherein the mixed digital voice stream that is configured for the participant node mixes a plurality of digital voice streams of participants of the VoIP conferencing except for the digital voice stream of the participant node; and
de-multiplexing, by the participant node, the multiplexed digital voice stream to obtain the mixed digital voice stream that is configured for the participant node.
2. The method of claim 1 , wherein the transmitting comprises:
receiving an analog voice stream from a phone card of the participant node; and
converting the analog voice stream into the digital voice stream.
3. The method of claim 2 , wherein the phone card aggregates one or more handsets or one or more subtended phone cards.
4. The method of claim 2 , further comprising:
performing analog echo cancellation on the analog voice stream received from the phone card.
5. The method of claim 2 , further comprising:
converting the mixed digital voice stream into a mixed analog voice stream; and
sending the mixed analog voice stream to the phone card of the participant node.
6. A method of voice over Internet protocol (VoIP) conferencing, comprising:
receiving by a master node, a plurality of digital voice streams from a plurality of participant nodes over a plurality of unicast sessions;
generating, by a mixer at the master node, a plurality of mixed digital voice streams, wherein each mixed digital voice stream in the plurality of mixed digital voice streams is configured for a corresponding one of the plurality of participant nodes, wherein, for each participant node in the plurality of participant nodes, a mixed digital voice stream that is configured for that participant node includes an ingress digital voice stream of the master node and the plurality of digital voice streams of the plurality of participant nodes except for a digital voice stream received from that participant node for which the mixed digital voice stream is configured;
multiplexing, by the master node, the plurality of mixed digital voice streams into a multiplexed digital voice stream; and
transmitting, by the master node, the multiplexed digital voice stream to the plurality of participant nodes over a multicast session.
7. The method of claim 6 , wherein the generating further comprises:
receiving an analog voice stream from a master phone card of the master node; and
converting the analog voice stream into the ingress digital voice stream.
8. The method of claim 7 , wherein the master phone card aggregates one or more handsets or one or more subtended phone cards.
9. The method of claim 7 , further comprising:
performing analog echo cancellation on the analog voice stream received from the master phone card.
10. The method of claim 7 , further comprising:
mixing the plurality of digital voice streams into a master mixed digital voice stream;
converting the master mixed digital voice stream into a mixed analog voice stream; and
sending the mixed analog voice stream to the master phone card of the master node.
11. A participant node for voice over Internet protocol (VoIP) conferencing, comprising:
a transceiver configured to:
transmit a digital voice stream to a master node over a unicast session; and
receive a multiplexed digital voice stream from the master node over a multicast session, wherein the multiplexed digital voice stream includes a plurality of mixed digital voice streams, wherein each mixed digital voice stream in the multiplexed digital voice stream is generated by a mixer at the master node and is configured for a corresponding participant of the VoIP conferencing, wherein the plurality of mixed digital voice streams include a mixed digital voice stream that is configured for the participant node, wherein the mixed digital voice stream that is configured for the participant node mixes a plurality of digital voice streams of participants of the VoIP conferencing except for the digital voice stream of the participant node;
and a de-multiplexer configured to de-multiplex the multiplexed digital voice stream to obtain the mixed digital voice stream that is configured for the participant node.
12. The participant node of claim 11 , further comprising:
a phone card; and
an analog to digital converter (ADC) configured to:
receive an analog voice stream from the phone card;
convert the analog voice stream into the digital voice stream; and
send the digital voice stream to the transceiver for transmitting to the master node.
13. The participant node of claim 12 , wherein the phone card aggregates one or more handsets or one or more subtended phone cards.
14. The participant node of claim 12 , further comprising:
an analog hybrid filtering circuit configured to perform analog echo cancellation on the analog voice stream received from the phone card.
15. The participant node of claim 12 , further comprising:
a digital to analog converter (DAC) configured to convert the mixed digital voice stream into a mixed analog voice stream, wherein the mixed analog voice stream is input to the phone card.
16. A master node for voice over Internet protocol (VoIP) conferencing, comprising:
a transceiver configured to receive a plurality of digital voice streams from a plurality of participant nodes over a plurality of unicast sessions;
a mixer configured to generate a plurality of mixed digital voice streams, wherein each mixed digital voice stream in the plurality of mixed digital voice streams is configured for a corresponding one of the plurality of participant nodes, wherein, for each participant node in the plurality of participant nodes, a mixed digital voice stream that is configured for that participant node includes an ingress digital voice stream of the master node and the plurality of digital voice streams of the plurality of participant nodes except for a digital voice stream received from that participant node for which the mixed digital voice stream is configured;
a multiplexer configured to multiplex the plurality of mixed digital voice streams into a multiplexed digital voice stream; and
wherein the transceiver is further configured to transmit the multiplexed digital voice stream to the plurality of participant nodes over a multicast session.
17. The master node of claim 16 , further comprising:
a master phone card; and
an analog to digital converter (ADC) configured to:
receive an analog voice stream from the master phone card;
convert the analog voice stream into the ingress digital voice stream; and
send the ingress digital voice stream to the transceiver for generating the plurality of mixed digital voice streams.
18. The master node of claim 17 , wherein the master phone card aggregates one or more handsets or one or more subtended phone cards.
19. The master node of claim 17 , further comprising:
an analog hybrid filtering circuit configured to perform analog echo cancellation on the analog voice stream received from the master phone card.
20. The master node of claim 17 , wherein the mixer is further configured to mix the plurality of digital voice streams into a master mixed digital voice stream, the master node further comprising:
a digital to analog converter (DAC) configured to convert the master mixed digital voice stream into a mixed analog voice stream, wherein the mixed analog voice stream is input to the master phone card.