# US 9,520,927 B2 · Including feedback information regarding an individual subband of a wireless channel > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,927 B2 - Document ID: US9520927B2 - Status: Granted - Kind: B2 - Application number: 14/481,063 - Filed: 2014-09-09 - Published: 2014-12-25 - Granted: 2016-12-13 - Earliest claimed: 2008-06-25 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Sairamesh Nammi; Shankar Venkatraman; Gaurav Hemrajani; Ashvin Chheda; Lai King Tee; Neng Wang; Kathiravetpillai Sivanesan - Web page: https://patentgrep.com/patent/US9520927B2 ## CPC - H04B 7/0417: Feedback systems - H04B 7/0619: {using feedback from receiving side (feedback signaling for adaptive modulation/coding H04L1/0001)} - H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection} - H04L 5/0096: {Indication of changes in allocation} - H04W 4/20: Services signaling; Auxiliary data signalling, i.e. transmitting data via a non-traffic channel - H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract To report feedback information regarding a wireless channel, a mobile station determines whether a predefined condition is satisfied. In response to determining that the predefined condition is satisfied, feedback information regarding an individual one of plural subbands of the wireless channel is included in a first report to be sent to a base station. In response to determining that the predefined condition is not satisfied, aggregate feedback information regarding the plural subbands is included in a second report to be sent to the base station. ## Claims ### Claim 1 A method of reporting feedback information regarding a wireless channel comprising: determining, by a mobile station, whether preferred subbands of the wireless channel are not changing, wherein said determining whether the preferred subbands of the wireless channel are not changing comprises determining whether a bitmap for a current reporting interval is unchanged from a bitmap for a prior reporting interval, wherein the bitmap identifies the preferred subbands; in response to determining that the preferred subbands of the wireless channel are not changing: transmitting in a first report to a base station, feedback information regarding an individual one of plural subbands of the wireless channel; and receiving, from the base station on the wireless channel, data precoded based on the first report; and in response to determining that the preferred subbands of the wireless channel are changing: transmitting in a second report to the base station, aggregate feedback information regarding the plural subbands; and receiving, from the base station on the wireless channel, data precoded based on the second report. ### Claim 2 (depends on 1) The method of claim 1, wherein the aggregate feedback information includes an average of the plurality of subbands. ### Claim 3 (depends on 1) The method of claim 1, wherein determining if the bitmap identifying preferred subbands has not changed comprises determining if a number of bits that correspond to one or more of the preferred subbands has not changed. ### Claim 4 (depends on 1) The method of claim 1, further comprising: after sending the first report, including, in a third report to be sent to the base station, further feedback information regarding a second individual one of the plural subbands if the preferred subbands of the wireless channel are not changing. ### Claim 5 (depends on 1) The method of claim 1, further comprising: including in the first report further feedback information regarding a second individual one of the plural subbands. ### Claim 6 (depends on 1) The method of claim 1, further comprising: performing, by the mobile station, data communication using one or more of the plural subbands that are less than all available subbands of the wireless channel. ### Claim 7 (depends on 1) The method of claim 1, wherein performing the data communication is according to a closed loop MIMO (multiple input, multiple output) mode of operation. ### Claim 8 (depends on 7) The method of claim 7, wherein the mobile station is to transmit plural codewords, and wherein the feedback information included in the first report is for a first of the plural codewords, and wherein the first report further includes feedback information for an individual subband for another one of the plural codewords. ### Claim 9 (depends on 1) The method of claim 1, wherein the feedback information in the first report for the individual subband comprises at least one of: a precoding matrix index (PMI); and channel quality indicator (CQI). ### Claim 10 A base station comprising: an interface to communicate wirelessly over a wireless channel with a mobile station; and a processor configured to: determine whether preferred subbands of the wireless channel are not changing, wherein to determine whether the preferred subbands of the wireless channel are not changing, the processor is further configured to determine if a bitmap for a current reporting interval is unchanged from a bitmap for a prior reporting interval, wherein the bitmap identifies the preferred subbands; in response to determining that preferred subbands of the wireless channel are not changing: using individual feedback information for an individual subband of plural subbands of the wireless channel; and transmitting, on the wireless channel, data precoded based on the individual feedback information; and in response to determining that preferred subbands of the wireless channel are changing: using aggregate feedback information for the plural subbands; and transmitting, on the wireless channel, data precoded based on the aggregate feedback information. ### Claim 11 (depends on 10) The base station of claim 10, wherein the aggregate feedback information includes an average of the plurality of subbands. ### Claim 12 (depends on 10) The base station of claim 10, wherein the individual feedback information or aggregate feedback information is used for downlink signaling and traffic data to be sent to the mobile station. ### Claim 13 (depends on 10) The base station of claim 10, wherein the individual feedback information comprises at least one of: an individual channel quality indicator (CQI); and an individual precoding matrix index (PMI). ### Claim 14 A mobile station comprising: an interface to communicate wirelessly over a wireless channel with a base station; and a processor configured to: determine whether preferred subbands of the wireless channel are not changing, wherein to determine whether the preferred subbands of the wireless channel are not changing, the processor is further configured to determine if a bitmap for a current reporting interval is unchanged from a bitmap for a prior reporting interval, wherein the bitmap identifies the preferred subbands; in response to determining that the preferred subbands of the wireless channel are not changing: transmit in a first report to a base station, feedback information regarding an individual one of plural subbands of the wireless channel; and receive, from the base station on the wireless channel, data precoded based on the first report; and in response to determining that the preferred subbands of the wireless channel are changing: transmit in a second report to the base station, aggregate feedback information regarding the plural subbands; and receive, from the base station on the wireless channel, data precoded based on the second report. ### Claim 15 (depends on 14) The mobile station of claim 14, wherein the aggregate feedback information includes an average of the plurality of subbands. ### Claim 16 (depends on 14) The mobile station of claim 14, wherein the first report includes a bitmap identifying the plural subbands as being preferred subbands. ### Claim 17 (depends on 14) The mobile station of claim 14, wherein the individual feedback information includes at least one of: an individual channel quality indicator (CQI); and an individual precoding matrix index (PMI). ### Claim 18 (depends on 14) The mobile station of claim 14, wherein to determine whether preferred subbands of the wireless channel are not changing the processor is further configured to: determine whether the bitmap identifying the preferred subbands remains the same in successive reporting intervals. ### Claim 19 (depends on 14) The mobile station of claim 14, wherein to determine whether preferred subbands of the wireless channel are not changing comprises determining if a number of bits that correspond to one or more of the preferred subbands has not changed. ### Claim 20 (depends on 10) The base station of claim 10, wherein determining if the bitmap identifying preferred subbands has not changed comprises determining if a number of bits that correspond to one or more of the preferred subbands has not changed.