# US 8,275,386 B2 · Apparatus and method for adaptive channel quality feedback in a multicarrier wireless network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,275,386 B2 - Document ID: US8275386B2 - Status: Granted - Kind: B2 - Application number: 12/945,567 - Filed: 2010-11-12 - Published: 2011-03-17 - Granted: 2012-09-25 - Earliest claimed: 2006-06-27 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Farooq Khan - Web page: https://patentgrep.com/patent/US8275386B2 ## CPC - H04L 1/0026: {Transmission of channel quality indication} - H04L 5/0044: {Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH} - H04L 5/006: {Quality of the received signal, e.g. BER, SNR, water filling} - H04L 5/0091: {Signalling for the administration of the divided path, e.g. signalling of configuration information} - H04W 24/08: Testing, {supervising or monitoring} using real traffic - H04W 72/542: using measured or perceived quality - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L 27/261: {Details of reference signals} - H04L 27/2626: {Arrangements specific to the transmitter only} - H04L 27/2647: {Arrangements specific to the receiver only (equalisation H04L27/01)} - 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 A subscriber station for use in a wireless network capable of communicating according to a multicarrier protocol. The subscriber station determines a total average signal level across N subbands, where each of subband comprises a plurality of subcarriers. The subscriber station also determines a first average signal level within a first subband. The subscriber station then transmits a channel quality indicator (CQI) feedback message to the wireless network. The CQI feedback message comprises a first data field indicating the total average signal level and a second data field indicating the first average signal level. The first data field may indicate the total average signal level as an absolute value and the second data field may indicate the first average signal level relative to the total average signal level. ## Claims ### Claim 1 A subscriber station configured to communicate according to a multi-carrier protocol, the subscriber station comprising: a transmitter configured to: determine a first channel quality indicator value indicating, channel quality across N subbands and a second channel quality indicator value indicating channel quality within one subband of the N subbands, and generate a feedback message including first data and second data, the first data indicating the first channel quality indicator value and the second data representing a value indicating a relative difference between the second channel quality indicator value and the first channel quality indicator value, and transmit the feedback message. ### Claim 2 (depends on 1) The subscriber station as set forth in claim 1, wherein the first data indicates the first channel quality indicator value using four bits and the second data represents the value indicating the relative difference between the second channel quality indicator value and the first channel quality indicator value using two bits. ### Claim 3 (depends on 1) The subscriber station as set forth in claim 1, wherein the first channel quality indicator value is determined based on effective Signal-to-Noise Ratio (SNR), the effective SNR, SNREFF, being calculated using C = 1 K · ∑ k = 1 K ⁢ ⁢ log ⁡ ( 1 + S ⁢ ⁢ N ⁢ ⁢ R k ) , and SNREFF=2C-1, where K is a total number of subcarriers and SNRK is the SNR of a k-th subcarrier. ### Claim 4 (depends on 1) The subscriber station as set forth in claim 1, wherein the transmitter is configured to determine the first channel quality indicator value based on all subcarriers in the N subbands. ### Claim 5 (depends on 1) The subscriber station as set forth in claim 1, wherein the transmitter is configured to determine the first channel quality indicator value based on a subset of all subcarriers in the N subbands, the subset including subcarriers from two or more of the N subbands. ### Claim 6 (depends on 1) The subscriber station as set forth in claim 1, wherein the transmitter is configured to determine the second channel quality indicator value based on all subcarriers in the one subband of the N subbands. ### Claim 7 (depends on 1) The subscriber station as set forth in claim 1, wherein the transmitter is configured to determine the second channel quality indicator value based on a subset of all subcarriers in the one subband of the N subbands. ### Claim 8 (depends on 1) The subscriber station as set forth in claim 1, wherein the relative difference is a differential offset level. ### Claim 9 (depends on 1) The subscriber station as set forth in claim 1, wherein the first channel quality indicator value is a wideband channel quality indicator value and the second channel quality indicator value is a subband channel quality indicator value. ### Claim 10 For use in a wireless network, a base station configured to communicate with a plurality of subscriber stations according to a multi-carrier protocol, wherein the base station transmits in a downlink to the plurality of subscriber stations using N subbands, each of the N subbands comprising a plurality of subcarriers, the base station comprising: a receiver configured to receive from a first one of the plurality of subscriber stations a feedback message, the feedback message comprising first data representing a first channel quality indicator value indicating channel quality determined by the first subscriber station across the N subbands and second data representing a value indicating a relative difference between the first channel quality indicator value and a second channel quality indicator value indicating channel quality determined by the first subscriber station within one subband of the N subbands, wherein the base station is configured to use the first and second data from the feedback message to allocate a group of subcarriers for transmitting in the downlink to the first subscriber station. ### Claim 11 (depends on 10) The base station as set forth in claim 10, wherein the first data indicates the first channel quality indicator value using four bits and the second data represents the value indicating the relative difference between the second channel quality indicator value and the first channel quality indicator value using two bits. ### Claim 12 (depends on 10) The base station as set forth in claim 10, wherein the first channel quality indicator value is determined based on effective Signal-to-Noise Ratio (SNR), the effective SNR, SNREFF, being calculated using C = 1 K · ∑ k = 1 K ⁢ ⁢ log ⁡ ( 1 + S ⁢ ⁢ N ⁢ ⁢ R k ) , and SNREFF=2C-1, where K is a total number of subcarriers and SNRK is the SNR of a k-th subcarrier. ### Claim 13 (depends on 10) The base station as set forth in claim 10, wherein the first channel quality indicator value is determined based on all subcarriers in the N subbands. ### Claim 14 (depends on 10) The base station as set forth in claim 10, wherein the first channel quality indicator value is determined based on a subset of all subcarriers in the N subbands, the subset including subcarriers from two or more of the N subbands. ### Claim 15 (depends on 10) The base station as set forth in claim 10, wherein the second channel quality indicator value is determined based on all subcarriers in the one subband of the N subbands. ### Claim 16 (depends on 10) The base station as set forth in claim 10, wherein the second channel quality indicator value is determined based on a subset of all subcarriers in the one subband of the N subbands. ### Claim 17 (depends on 10) The base station as set forth in claim 10, wherein the relative difference is a differential offset level. ### Claim 18 (depends on 10) The base station as set forth in claim 10, wherein the first channel quality indicator value is a wideband channel quality indicator value and the second channel quality indicator value is a subband channel quality indicator value.