# US 2020/0403674 A1 · Efficient calibration for implicit feedback > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0403674 A1 - Document ID: US20200403674A1 - Status: Published application - Kind: A1 - Application number: 17/013,362 - Filed: 2020-09-04 - Published: 2020-12-24 - Earliest claimed: 2019-09-04 - Inventors: Qinghua Li; Ziv Avital; Xiaogang Chen; Assaf Gurevitz; Po-Kai Huang; Feng Jiang; Robert Stacey - Web page: https://patentgrep.com/patent/US20200403674A1 ## CPC - H04B 7/0617: {for beam forming} - H04B 17/12: of transmit antennas, e.g. of the amplitude or phase - H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection} - H04B 17/14: of the whole transmission and reception path, e.g. self-test loop-back - H04B 17/221: {of receiver antennas, e.g. as to amplitude or phase} - H04B 17/24: with feedback of measurements to the transmitter - H04L 25/0204: {of multiple channels} - H04L 25/0228: {with direct estimation from sounding signals} - H04L 43/12: Network monitoring probes - H04W 24/02: Arrangements for optimising operational condition - H04B 7/061: {using feedback from receiving side} - H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports} - 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 This disclosure describes systems, methods, and devices related to efficient calibration for implicit feedback. A device may cause to send a first sounding frame to a first station device, wherein the first sounding frame is used for a calibration of a plurality of (TX) antennas and a plurality of (RX) antennas. The device may identify one or more quantization indices received from the first station device. The device may reconstruct the feedback vector using the one or more quantization indices. The device may identify a second sounding frame from the first station device. The device may determine second channel estimates based on the RX antenna at the first station device and the plurality of TX antennas at the device. The device may compare the reconstructed feedback vector with the second channel estimates. The device may determine a compensation scalar based on the comparison. ## Claims ### Claim 1 A device, the device comprising processing circuitry coupled to storage, the processing circuitry configured to: cause to send a first sounding frame to a first station device, wherein the first sounding frame is used for a calibration of a plurality of (TX) antennas and a plurality of (RX) antennas; identify one or more quantization indices received from the first station device, wherein the one or more quantization indices are associated with a quantization of a feedback vector, wherein the quantization of the feedback vector is performed by jointly quantizing first channel estimates from an RX antenna at the first station device and each of the plurality of TX antennas at the device; reconstruct the feedback vector using the one or more quantization indices; identify a second sounding frame from the first station device; determine second channel estimates based on the RX antenna at the first station device and the plurality of TX antennas at the device; compare the reconstructed feedback vector with the second channel estimates; and determine a compensation scalar based on the comparison. ### Claim 2 (depends on 1) The device of claim 1, wherein the compensation scalar is used to compensate for a difference between a transmit chain and a corresponding receive chain connected to a same TX antenna at the device. ### Claim 3 (depends on 2) The device of claim 2, wherein the processing circuitry is further configured to determine that ratios of a transmit chain response to a corresponding receive chain response remains the same for the plurality of TX antennas. ### Claim 4 (depends on 1) The device of claim 1, wherein the calibration is initiated by sending a null data packet announcement (NDPA) frame or a trigger frame. ### Claim 5 (depends on 1) The device of claim 1, wherein the processing circuitry is further configured to send one or more data frames on the plurality of the TX antennas by applying the compensation scalar to the one or more data frames. ### Claim 6 (depends on 1) The device of claim 1, wherein the second sounding frame is a null data packet (NDP) frame received from the first station device. ### Claim 7 (depends on 1) The device of claim 1, wherein the second sounding frame is a calibration feedback frame or any frame with data comprising one or more long training fields (LTFs). ### Claim 8 (depends on 7) The device of claim 7, wherein the one or more LTFs are used for channel estimation. ### Claim 9 A non-transitory computer-readable medium storing computer-executable instructions which when executed by one or more processors result in performing operations comprising: causing to send a first sounding frame to a first station device, wherein the first sounding frame is used for a calibration of a plurality of (TX) antennas and a plurality of (RX) antennas; identifying one or more quantization indices received from the first station device, wherein the one or more quantization indices are associated with a quantization of a feedback vector, wherein the quantization of the feedback vector is performed by jointly quantizing first channel estimates from an RX antenna at the first station device and each of the plurality of TX antennas at the device; reconstructing the feedback vector using the one or more quantization indices; identifying a second sounding frame from the first station device; determining second channel estimates based on the RX antenna at the first station device and the plurality of TX antennas at the device; comparing the reconstructed feedback vector with the second channel estimates; and determining a compensation scalar based on the comparison. ### Claim 10 (depends on 9) The non-transitory computer-readable medium of claim 9, wherein the compensation scalar is used to compensate for a difference between a transmit chain and a corresponding receive chain connected to a same TX antenna at the device. ### Claim 11 (depends on 10) The non-transitory computer-readable medium of claim 10, wherein the operations further comprise determining that ratios of a transmit chain response to a corresponding receive chain response remains the same for the plurality of TX antennas. ### Claim 12 (depends on 9) The non-transitory computer-readable medium of claim 9, wherein the calibration is initiated by sending a null data packet announcement (NDPA) frame or a trigger frame. ### Claim 13 (depends on 9) The non-transitory computer-readable medium of claim 9, wherein the operations further comprise send one or more data frames on the plurality of the TX antennas by applying the compensation scalar to the one or more data frames. ### Claim 14 (depends on 9) The non-transitory computer-readable medium of claim 9, wherein the second sounding frame is a null data packet (NDP) frame received from the first station device. ### Claim 15 (depends on 9) The non-transitory computer-readable medium of claim 9, wherein the second sounding frame is a calibration feedback frame or any frame with data comprising one or more long training fields (LTFs). ### Claim 16 (depends on 15) The non-transitory computer-readable medium of claim 15, wherein the one or more LTFs are used for channel estimation. ### Claim 17 A method comprising: causing to send a first sounding frame to a first station device, wherein the first sounding frame is used for a calibration of a plurality of (TX) antennas and a plurality of (RX) antennas; identifying one or more quantization indices received from the first station device, wherein the one or more quantization indices are associated with a quantization of a feedback vector, wherein the quantization of the feedback vector is performed by jointly quantizing first channel estimates from an RX antenna at the first station device and each of the plurality of TX antennas at the device; reconstructing the feedback vector using the one or more quantization indices; identifying a second sounding frame from the first station device; determining second channel estimates based on the RX antenna at the first station device and the plurality of TX antennas at the device; comparing the reconstructed feedback vector with the second channel estimates; and determining a compensation scalar based on the comparison. ### Claim 18 (depends on 17) The method of claim 17, wherein the compensation scalar is used to compensate for a difference between a transmit chain and a corresponding receive chain connected to a same TX antenna at the device. ### Claim 19 (depends on 18) The method of claim 18, further comprising determining that ratios of a transmit chain response to a corresponding receive chain response remains the same for the plurality of TX antennas. ### Claim 20 (depends on 17) The method of claim 17, wherein the calibration is initiated by sending a null data packet announcement (NDPA) frame or a trigger frame.