# US 9,520,931 B2 · System and method for unified feedback in a communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,931 B2 - Document ID: US9520931B2 - Status: Granted - Kind: B2 - Application number: 12/907,740 - Filed: 2010-10-19 - Published: 2011-05-05 - Granted: 2016-12-13 - Earliest claimed: 2009-11-02 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Jianglei Ma; Ming Jia; Mohammadhadi Baligh; Yang Tang - Inventors: Jianglei Ma; Ming Jia; Mohammadhadi Baligh; Yang Tang - Web page: https://patentgrep.com/patent/US9520931B2 ## CPC - H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection} - H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems - H04B: TRANSMISSION ## Abstract In an embodiment, a method of operating a communication device includes determining a first coordinated multipoint (CoMP) mode, electronically receiving feedback from a user device in the uniform feedback format, and determining transmission parameters of the first CoMP mode. The first CoMP mode includes one of a plurality of CoMP modes, and each of the plurality of CoMP modes is configured to operate using a uniform feedback format. ## Claims ### Claim 1 A method of operating a communication device, the method comprising: selecting one out of a plurality of coordinated multipoint (CoMP) transmission modes, wherein a uniform feedback format requires that only precoding matrix indicator (PMI) feedback parameters are reported for the selected CoMP transmission mode irrespective of which of the plurality of CoMP transmission modes is selected; receiving feedback from a user device in accordance with the uniform feedback format, wherein the feedback received from the user device includes the PMI feedback parameters for CoMP transmission while excluding other types of feedback parameters for CoMP transmission by virtue of the feedback being communicated in accordance with the uniform feedback format; and determining transmission parameters of the selected CoMP transmission mode. ### Claim 2 (depends on 1) The method of claim 1, wherein the uniform feedback format specifies that the same amount of PMI feedback information is reported irrespective of which CoMP transmission mode is selected. ### Claim 3 (depends on 2) The method of claim 2, wherein the selected CoMP transmission mode is a non-coherent joint transmission (JT) mode, wherein the communication device supports a serving cell or a cooperating cell, wherein the PMI feedback comprises a preferred PMI, and wherein the method further comprises: computing a precoder based on the feedback from the user device, precoding a transmission with the precoder, and transmitting the precoded transmission to the user device. ### Claim 4 (depends on 2) The method of claim 2, wherein the communication device further applies a multi-user multi-input-multi-output (MU-MIMO) transmission scheme in accordance with the feedback received from the user device. ### Claim 5 (depends on 2) The method of claim 2, wherein the selected CoMP transmission mode is a coherent joint transmission (JT) mode based on the determining, wherein the communication device comprises a base station supporting a serving cell or a cooperating cell, wherein the PMI feedback comprises a joint PMI for a combined channel and a PMI for coherent channel combining, and wherein the method further comprises: computing a precoder based on the feedback from the user device, precoding a transmission with the precoder, and transmitting the precoded transmission to the user device. ### Claim 6 (depends on 5) The method of claim 5, further comprising using high layer signaling to inform the user device of the selected CoMP transmission mode. ### Claim 7 (depends on 2) The method of claim 2, further comprising transmitting a command to the user device to broadcast feedback content according to a joint transmission (JT) scheme as a baseline feedback scheme, wherein the selected CoMP transmission mode is unknown by the user device. ### Claim 8 (depends on 2) The method of claim 2, wherein the selected CoMP transmission mode is a coordinated beam forming (CBF) mode. ### Claim 9 (depends on 8) The method of claim 8, wherein the communication device comprises a base station supporting a serving cell, wherein the PMI feedback comprises a preferred PMI, and wherein the method further comprises, if it is determined that the serving cell is to transmit to the user device, computing a precoder based on the PMI feedback, precoding a transmission with the precoder, and transmitting the precoded transmission to the user device. ### Claim 10 (depends on 8) The method of claim 8, wherein the communication device comprises a base station supporting a cooperating cell communicating with a first user device, wherein the PMI feedback comprises a companion PMI, and wherein the method further comprises, if it is determined that the cooperating cell is to transmit to the first user device, computing a precoder based on the PMI feedback, precoding a transmission with the precoder, and transmitting the precoded transmission to the first user device. ### Claim 11 (depends on 10) The method of claim 10, wherein the communication device further comprises a base station supporting a serving cell communicating with a second user device, and wherein the method further comprises communicating with the second user device in a joint processing mode, the communicating further comprising receiving PMI feedback from the second user device. ### Claim 12 (depends on 2) The method of claim 2, wherein the selected CoMP transmission mode is a dynamic cell selection (DCS) mode. ### Claim 13 (depends on 12) The method of claim 12, wherein the communication device comprises a base station supporting a serving cell, wherein the PMI feedback comprises a preferred PMI, and wherein the method further comprises, if it is determined that the serving cell is to transmit to the user device, computing a precoder based on the PMI feedback, precoding a transmission with the precoder, and transmitting the precoded transmission to the user device. ### Claim 14 (depends on 12) The method of claim 12, wherein the communication device comprises a base station supporting a cooperating cell, wherein the PMI feedback comprises a companion PMI, and wherein the method further comprises, if it is determined that the cooperating cell is to transmit to the user device, computing a precoder based on the PMI feedback, precoding a transmission with the precoder, and transmitting the precoded transmission to the user device. ### Claim 15 (depends on 1) The method of claim 1, wherein the uniform feedback format requires that only PMI feedback parameters are reported for each of the plurality of CoMP transmission modes. ### Claim 16 (depends on 1) The method of claim 1, further comprising: determining a non-CoMP transmission mode; and electronically receiving feedback parameters from the user device in accordance with the uniform feedback format while operating in the non-CoMP transmission mode. ### Claim 17 A communications device comprising: a transmitter; a receiver configured to receive feedback from a user device in accordance with a uniform feedback format; and a processor configured to: select one of a plurality of coordinated multipoint (CoMP) transmission modes, wherein the uniform feedback format requires that only precoding matrix indicator (PMI) feedback parameters are reported for the selected CoMP transmission mode irrespective of which of the plurality of CoMP transmission modes is selected, and wherein the feedback received from the user device includes the PMI feedback parameters for CoMP transmission while excluding other types of feedback parameters for CoMP transmission by virtue of the feedback being communicated in accordance with the uniform feedback format; and determine transmission parameters of the selected CoMP transmission mode in accordance with the feedback received from the user device. ### Claim 18 (depends on 17) The communications device of claim 17, wherein the uniform feedback format specifies that the same amount of precoder matrix indicator (PMI) feedback information is reported irrespective of which CoMP transmission mode is selected. ### Claim 19 (depends on 18) The communications device of claim 18, wherein the plurality of CoMP transmission modes comprises at least one of a coherent joint transmission (JT) mode, a non-coherent joint transmission (JT) mode, a coordinated beam forming (CBF) mode, and a dynamic cell selection mode (DCS) mode. ### Claim 20 (depends on 18) The communications device of claim 18, wherein the processor is configured to apply a multi-user multi-input-multi-output (MU-MIMO) transmission scheme in accordance with the feedback received from the user device. ### Claim 21 (depends on 17) The communications device of claim 17, wherein the processor selects the CoMP transmission mode in accordance with operation scenarios. ### Claim 22 (depends on 17) The communications device of claim 17, wherein the transmitter is configured to broadcast an indicator of the selected CoMP transmission mode to at least one user device. ### Claim 23 (depends on 22) The communications device of claim 22, wherein the transmitter is configured to transmit a command to the user device, the command instructing the user device to broadcast feedback content according to a joint transmission (JT) scheme as a baseline feedback scheme, and wherein the selected CoMP transmission mode is unknown by the user device. ### Claim 24 (depends on 17) The communications device of claim 17, wherein the uniform feedback format requires that only PMI feedback parameters are reported for each of the plurality of CoMP transmission modes. ### Claim 25 A method comprising: receiving, by a user device, an indication specifying that a coordinated multipoint (CoMP) communication mode will be used to communicate data to the user device, the CoMP communication mode being one of a plurality of CoMP communication modes; and reporting, by the user device, feedback information in accordance with a uniform feedback format, wherein the uniform feedback format requires that only precoding matrix indicator (PMI) feedback parameters are reported for the CoMP communication mode specified by the indication irrespective of which of the plurality of CoMP communication modes is specified by the indication, and wherein the feedback information reported by the user device includes the PMI feedback parameters for CoMP transmission while excluding other types of feedback parameters for CoMP transmission by virtue of the feedback information being communicated in accordance with the uniform feedback format. ### Claim 26 (depends on 25) The method of claim 25, wherein the plurality of CoMP communication modes comprises at least one of a coherent joint transmission (JT) mode; a non-coherent joint transmission (JT) mode; a coordinated beam forming (CBF) mode; and a dynamic cell selection mode (DCS) mode. ### Claim 27 (depends on 25) The method of claim 25, further comprising: receiving, by the user device, a second indication specifying a non-CoMP communication mode; and generating, by the user device, feedback information for the non-CoMP communication mode in accordance with the uniform feedback format, wherein the uniform feedback format specifies that the same type and number of feedback parameters are reported for non-CoMP communication modes as are reported for CoMP communication modes. ### Claim 28 (depends on 25) The method of claim 25, wherein the uniform feedback format specifies that the same amount of precoder matrix indicator (PMI) feedback information is reported irrespective of which CoMP transmission mode is selected. ### Claim 29 (depends on 25) The method of claim 25, wherein the uniform feedback format requires that only PMI feedback parameters are reported for each of the plurality of CoMP transmission modes. ### Claim 30 A user device comprising: a processor; and a computer readable storage medium storing programming for execution by the processor, the programming including instructions to: receive an indication specifying that a coordinated multipoint (CoMP) communication mode will be used to communicate data to the user device, wherein the CoMP communication mode is one of a plurality of CoMP communication modes; and report feedback information in accordance with a uniform feedback format, wherein the uniform feedback format requires that only precoding matrix indicator (PMI) feedback parameters are reported for the CoMP communication mode specified by the indication irrespective of which of the plurality of CoMP communication modes is specified by the indication, and wherein the feedback information reported by the user device includes the PMI feedback parameters for CoMP transmission while excluding other types of feedback parameters for CoMP transmission by virtue of the feedback information being communicated in accordance with the uniform feedback format. ### Claim 31 (depends on 30) The user device of claim 30, wherein the plurality of CoMP communication modes comprises at least one of a coherent joint transmission (JT) mode, a non-coherent joint transmission (JT) mode, a coordinated beam forming (CBF) mode, and a dynamic cell selection mode (DCS) mode. ### Claim 32 (depends on 30) The user device of claim 30, wherein the uniform feedback format specifies that the same amount of precoder matrix indicator (PMI) feedback information is reported irrespective of which CoMP transmission mode is selected. ### Claim 33 (depends on 30) The user device of claim 30, wherein the programming further includes instructions to: receive a second indication specifying a non-CoMP communication mode; and generate feedback information for the non-CoMP communication mode in accordance with the uniform feedback format, wherein the uniform feedback format specifies that the same type and number of feedback parameters are reported for non-CoMP communication modes as are reported for CoMP communication modes. ### Claim 34 (depends on 30) The user device of claim 30, wherein the uniform feedback format requires that only PMI feedback parameters are reported for each of the plurality of CoMP transmission modes.