# US 2018/0324237 A1 · Method for congestion control in multiparty conferencing, multipoint control unit, computer program and computer program product > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324237 A1 - Document ID: US20180324237A1 - Status: Published application - Kind: A1 - Application number: 15/772,863 - Filed: 2015-11-16 - Published: 2018-11-08 - Earliest claimed: 2015-11-16 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Ingemar JOHANSSON; Bo BURMAN; Frederic GABIN; Magnus WESTERLUND - Web page: https://patentgrep.com/patent/US20180324237A1 ## CPC - H04L 65/403: Arrangements for multi-party communication, e.g. for conferences (data switching systems for conference H04L12/18; arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities H04M3/56; television conferencing systems H04N7/15) - H04L 47/12: Avoiding congestion; Recovering from congestion - H04L 65/65: Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP] - H04L 65/765: {intermediate} - H04L 65/80: Responding to QoS - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method performed in a multipoint control unit for congestion control in multiparty conferencing is provided. The method includes forwarding packets of a media stream from the sending part to receiving parts of the multiparty conference, the receiving parts being two or more; receiving, from each receiving part, a respective receiver feedback report on the reception of the packets; establishing a sender feedback report comprising a timestamp (TSRX) for a given packet sequence number, wherein the timestamp reflects a wall-clock time when the packet with the given packet sequence number have been acknowledged by a threshold number of the receiving parts; and providing the established sender feedback report to the sending part. A multipoint control unit, computer program and computer program products are also provided. ## Claims ### Claim 1 A method performed in a multipoint control unit for congestion control in multiparty conferencing, the method comprising: forwarding packets of a media stream from the sending part to receiving parts of the multiparty conference, there being at least two receiving parts; receiving, from each receiving part, a respective receiver feedback report on the reception of the packets; establishing a sender feedback report comprising a timestamp (TSRX) for a given packet sequence number, the timestamp reflecting a wall-clock time when the packet with the given packet sequence number have been acknowledged by a threshold number of the receiving parts; and providing the established sender feedback report to the sending part. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the threshold number of receiving parts having acknowledged the packet is set to one of: more than 50% of all receiving parts; more than 70% of all receiving parts; more than 90% of all receiving parts; more than 95% of all receiving parts; and 100% of all receiving parts. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the establishing comprises determining the timestamp (TSRX) such that at least one receiver feedback report is excluded. ### Claim 4 (depends on 3) The method as claimed in claim 3, further comprising one of transcoding and stream thinning the media stream for each of the at least one receiving parts for which a receiver feedback report is excluded. ### Claim 5 (depends on 1) The method as claimed in claim 1, further comprising retransmitting a packet to a receiving part that has indicated in its feedback report the packet as lost. ### Claim 6 (depends on 1) The method as claimed in claim 1, further comprising setting a source quench bit in the sender feedback report when at least one received feedback report from the at least two receiving parts comprises a source quench bit being set. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein the multipoint control unit utilizes feedback elements of Self-clocking Rate Adaptation for Multimedia, SCReAM, congestion control. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein the received receiver feedback reports comprise a feedback element, Nloss, counting accumulated number of lost packets, and the method further comprises: increasing a counter (C1) whenever a received feedback report indicates an increase in the feedback element, Nloss, and including a feedback element, Nloss, in the sender feedback report based on the counter (C1) value. ### Claim 9 (depends on 1) The method as claimed in claim 1, further comprising switching between a first and a second sender and wherein the providing comprises providing a respective sender feedback report with a delay calculated based on a round trip delay between the multipoint control unit and at least one of the receiving parts. ### Claim 10 A computer storage medium storing a computer program for a multipoint control unit for congestion control in multiparty conferencing, the computer program comprising computer program code, which, when executed on at least one processor of the multipoint control unit causes the multipoint control unit to perform the method to: forward packets of a media stream from the sending part to receiving parts of the multiparty conference, there being at least two receiving parts; receive, from each receiving part, a respective receiver feedback report on the reception of the packets; establish a sender feedback report comprising a timestamp (TSRX) for a given packet sequence number, the timestamp reflecting a wall-clock time when the packet with the given packet sequence number have been acknowledged by a threshold number of the receiving parts, and provide the established sender feedback report to the sending part. ### Claim 11 (canceled) ### Claim 12 A multipoint control unit for congestion control in multiparty conferencing, the multipoint control unit being configured to: forward packets of a media stream from the sending part to receiving parts of the multiparty conference, the receiving parts being two or more of the multiparty conference, there being at least two receiving parts; receive, from each receiving part, a respective receiver feedback report on the reception of the packets; establish a sender feedback report comprising a timestamp (TSRX) for a given packet sequence number, wherein the timestamp reflects a wall-clock time when the packet with the given packet sequence number have been acknowledged by a threshold number of the receiving parts; and provide the established sender feedback report to the sending part. ### Claim 13 (depends on 12) The multipoint control unit as claimed in claim 12, wherein the threshold number of receiving parts having acknowledged the packet is set to one of: more than 50% of all receiving parts; more than 70% of all receiving parts; more than 90%y of all receiving parts; more than 95% of all receiving parts; and 100% of all receiving parts. ### Claim 14 (depends on 12) The multipoint control unit as claimed in claim 12, further configured to establish by determining the timestamp (TSRX) such that at least one receiver feedback report is excluded. ### Claim 15 (depends on 14) The multipoint control unit as claimed in claim 14, further configured to one of transcode and stream thinning the media stream for each of the at least one receiving parts for which a receiver feedback report is excluded. ### Claim 16 (depends on 12) The multipoint control unit as claimed in claim 12, further configured to retransmit a packet to a receiving part that has indicated in its feedback report the packet as lost. ### Claim 17 (depends on 12) The multipoint control unit as claimed in claim 12, further configured to set a source quench bit in the sender feedback report when at least one received feedback report from the at least two receiving parts comprises a source quench bit being set. ### Claim 18 (depends on 12) The multipoint control unit as claimed in claim 12, further configured to utilize feedback elements of Self-clocking Rate Adaptation for Multimedia, SCReAM, congestion control. ### Claim 19 (depends on 12) The multipoint control unit as claimed in claim 12, wherein the received receiver feedback reports comprise a feedback element, Nloss, counting accumulated number of lost packets, and the multipoint control unit is further configured to: increase a counter whenever a received feedback report indicates an increase in the feedback element, Nloss, and to include a feedback element, Nloss, in the sender feedback report based on the counter value. ### Claim 20 (depends on 12) The multipoint control unit as claimed in claim 12, further configured to switch between a first and a second sender and configured to provide a respective sender feedback report with a delay calculated based on a round trip delay between the multipoint control unit and at least one of the receiving parts. ### Claim 21 (depends on 2) The method as claimed in claim 2, wherein the establishing comprises determining the timestamp (TSRX) such that at least one receiver feedback report is excluded.