# US 8,542,609 B2 · Multicast rate optimization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,609 B2 - Document ID: US8542609B2 - Status: Granted - Kind: B2 - Application number: 13/059,825 - Filed: 2009-08-20 - Published: 2011-06-23 - Granted: 2013-09-24 - Earliest claimed: 2008-08-20 - Assignees: Google Inc. - Applicants: Ermin Kozica - Inventors: Ermin Kozica - Web page: https://patentgrep.com/patent/US8542609B2 ## CPC - H04L 12/1877: {Measures taken prior to transmission} - H04L 65/611: for multicast or broadcast (systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06) - H04L 65/70: Media network packetisation - H04N 21/44209: {Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network (arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896)} - H04N 21/6131: {involving transmission via a mobile phone network (wireless downlink channel access H04W74/006)} - H04N 21/6181: {involving transmission via a mobile phone network (arrangements for providing broadcast or conference services to substation in data switching networks in combination with wireless systems H04L12/189; wireless uplink channel access H04W74/004)} - H04N 21/6379: directed to encoder {, e.g. for requesting a lower encoding rate} - H04N 21/6405: Multicasting {(data broadcast and multicast in packet switching networks H04L12/18)} - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04W 28/22: Negotiating communication rate - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract This invention relates to multicast rate optimization, particularly a method for controlling an encoder (1) in a communications system (3) including a plurality of receivers (2). The method includes partitioning the receivers (2) into at least one cell, and associating each cell with a specific rate that may be used to transmit signals to a receiver (2). According to the inventive method, uncertainties in estimates of conditions of the communications system (3) are taken into account by modelling the conditions, such as the average distortion perceived by the receivers (2), as the outcome of a stochastic variable, thereby accounting for uncertainties in the estimates of the conditions of the communications system (3). The invention also relates to an encoder associated with the method. ## Claims ### Claim 1 A method for controlling an encoder in a communications system including a plurality of receivers, wherein the encoder output consists of a plurality of streams, and wherein a first decodable subset of the plurality of streams is decoded independently of a second decodable subset of the plurality of the streams, the method including the steps of: (a) partitioning the plurality of receivers into a plurality of cells, wherein each of the cells is associated with a decodable subset of the streams; (b) assigning an initial transmission rate to each decodable subset of the streams based on an estimate of available bandwidth for communicating with receivers in the cell associated with the decodable subset of the streams; (c) for a first cell of the plurality of cells, determining an average distortion perceived by the receivers in the first cell and the receivers in cells bordering the first cell given the initial transmission rate assigned to the decodable subset of the streams associated with the first cell; (d) determining whether the average distortion exceeds a threshold distortion; (e) in response to determining that the average distortion exceeds the threshold distortion, assigning a new transmission rate to the decodable subset of the streams associated with the first cell, wherein the new transmission rate is based on minimizing the average distortion perceived by the receivers in the cells bordering the first cell; and (f) controlling the encoder to output the decodable subset of the streams associated with the first cell in accordance with the new transmission rate assigned to the decodable subset of the streams; wherein the decodable subsets of the streams have one or more of the following adaptable properties: the signal representation length per time unit; the error resilience; and the erasure resilience. ### Claim 2 (depends on 1) The method according to claim 1, wherein steps (c)-(e) are performed for one or more other cells of the plurality of cells, and step (f) further comprises controlling the encoder to output the decodable subsets of the streams associated with the one or more other cells in accordance with the new transmission rates assigned to the decodable subsets of the streams. ### Claim 3 (depends on 2) The method according to claim 2, wherein the one or more other cells are selected randomly, according to a predefined order, or such that for each of the one or more other cells selected, the average distortion perceived by the receivers contained in cells bordering the cell is decreased the most compared to choosing any other cell of the plurality of cells. ### Claim 4 (depends on 1) The method according to claim 1, wherein the encoder includes one or more of the following: a plurality of sub-encoders, each sub-encoder outputting one stream, wherein each sub-encoder is provided with a property of the stream that is outputted by the sub-encoder, and a layered or multiple-description encoder outputting a plurality of streams forming a number of decodable subsets, wherein said encoder is provided with a property for each decodable subset that is outputted by said encoder. ### Claim 5 (depends on 1) The method according to claim 1, further comprising receiving feedback information for the plurality of receivers, wherein the feedback information includes a measure of the rate that may be used to transmit signals to a receiver. ### Claim 6 (depends on 1) The method according to claim 1, wherein the plurality of streams includes video or audio signals. ### Claim 7 An encoder for use in a communications system including a plurality of receivers, wherein the encoder output consists of a plurality of streams, and wherein a first decodable subset of the plurality of streams is decoded independently of a second decodable subset of the plurality of the streams, the encoder including: a control unit configured to: (a) partition the plurality of receivers into a plurality of cells, wherein each of the cells is associated with a decodable subset of the streams, (b) assign an initial transmission rate to each decodable subset of the streams based on an estimate of available bandwidth for communicating with receivers in the cell associated with the decodable subset of the streams; (c) for a first cell of the plurality of cells, determine an average distortion perceived by the receivers in the first cell and the receivers in cells bordering the first cell given the initial transmission rate assigned to the decodable subset of the streams associated with the first cell; (d) determine whether the average distortion exceeds a threshold distortion; (e) in response to determining that the average distortion exceeds the threshold distortion, assign a new transmission rate to the decodable subset of the streams associated with the first cell, wherein the new transmission rate is based on minimizing the average distortion perceived by the receivers in the cells bordering the first cell; and (f) control the encoder by outputting the decodable subset of the streams associated with the first cell in accordance with the new transmission rate assigned to the decodable subset of the streams; and wherein the decodable subsets of the streams have one or more of the following adaptable properties: the signal representation length per time unit; the error resilience; and the erasure resilience. ### Claim 8 (depends on 7) The encoder according to claim 7, wherein the control unit is further configured to perform (c)-(e) for one or more other cells of the plurality of cells, and control the encoder by outputting the decodable subsets of the streams associated with the one or more other cells in accordance with the new transmission rates assigned to the decodable subsets of the streams. ### Claim 9 (depends on 8) The encoder according to claim 8, wherein the control unit is further configured to select the one or more other cells randomly, according to a predefined order, or such that for each of the one or more other cells selected, the average distortion perceived by the receivers contained in cells bordering the cell is decreased the most compared to choosing any other cell of the plurality of cells. ### Claim 10 (depends on 7) The encoder according to claim 7, further including one or more of the following: a plurality of sub-encoders, each sub-encoder outputting one stream, wherein each sub-encoder is provided with a property of the stream that is outputted by the sub-encoder, and a layered or multiple-description encoder outputting a plurality of streams forming a number of decodable subsets, wherein said encoder is provided with a property for each decodable subset that is outputted by said encoder. ### Claim 11 (depends on 7) The encoder according to claim 7, wherein the control unit is further adapted to receive feedback information for the plurality of receivers, wherein the feedback information includes a measure of the rate that may be used to transmit signals to a receiver. ### Claim 12 (depends on 7) The encoder according to claim 7, wherein the plurality of streams includes video or audio signals. ### Claim 13 (depends on 2) The method according to claim 2, wherein the encoder includes one or more of the following: a plurality of sub-encoders, each sub-encoder outputting one stream, wherein each sub-encoder is provided with a property of the stream that is outputted by the sub-encoder, and a layered or multiple-description encoder outputting a plurality of streams forming a number of decodable subsets, wherein said encoder is provided with a property for each decodable subset that is outputted by said encoder. ### Claim 14 (depends on 3) The method according to claim 3, wherein the encoder includes one or more of the following: a plurality of sub-encoders, each sub-encoder outputting one stream, wherein each sub-encoder is provided with a property of the stream that is outputted by the sub-encoder, and a layered or multiple-description encoder outputting a plurality of streams forming a number of decodable subsets, wherein said encoder is provided with a property for each decodable subset that is outputted by said encoder. ### Claim 15 (depends on 5) The method according to claim 5, further comprising obtaining estimates of transmission quality measures of the decodable subsets of the streams by modeling the measure of the rate that may be used to transmit signals to the receiver. ### Claim 16 (depends on 15) The method according to claim 15, further comprising controlling the encoder to output the decodable subsets of the streams in accordance with the obtained estimates of transmission quality measures of the decodable subsets of the streams. ### Claim 17 (depends on 15) The method according to claim 15, wherein the measure of the rate that may be used to transmit signals to the receiver is modeled using a continuous stochastic variable while minimizing the distortion perceived by the receiver. ### Claim 18 (depends on 7) The encoder according to claim 7, wherein the control unit is further configured to obtain estimates of transmission quality measures of the decodable subsets of the streams by modeling the measure of the rate that may be used to transmit signals to the receiver. ### Claim 19 (depends on 18) The encoder according to claim 18, wherein the control unit is further configured to control the encoder by outputting the decodable subsets of the streams in accordance with the obtained estimates of transmission quality measures of the decodable subsets of the streams. ### Claim 20 (depends on 18) The encoder according to claim 18, wherein the control unit is further configured to model the measure of the rate using a continuous stochastic variable while minimizing the distortion perceived by the receiver.