# US 12,003,353 B2 · Coverage enhanced reciprocity-based precoding scheme > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,003,353 B2 - Document ID: US12003353B2 - Status: Granted - Kind: B2 - Application number: 17/428,841 - Filed: 2019-11-11 - Published: 2022-04-21 - Granted: 2024-06-04 - Earliest claimed: 2019-02-06 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Mohammadreza Malek-Mohammadi; Karl Werner - Web page: https://patentgrep.com/patent/US12003353B2 ## CPC - H04L 25/03898: {codebook-based design (selection of codebook or precoding matrix for MIMO diversity systems H04B7/0456)} - H04B 7/0617: {for beam forming} - H04L 25/0212: {of impulse response} - H04L 25/0224: {using sounding signals} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract Systems and methods for coverage enhanced reciprocity-based precoding schemes are provided. In some embodiments, a method performed by a base station for determining precoding information includes: determining channel estimates for at least a channel between the wireless device and another device; determining a plurality of precoding hypotheses based on the channel estimates; determining a figure of merit for each of the plurality of precoding hypotheses; and determining the precoding information based on the figure of merit for each of the plurality of precoding hypotheses. In some embodiments, this precoding method enables the use of reciprocity-based precoding down to a lower Signal to Noise Ratio, SNR, than what existing state of the art reciprocity-based precoding can offer. ## Claims ### Claim 1 A method performed by a radio node for determining precoding information, the method comprising: determining channel estimates for at least a channel between the radio node and another device; determining a plurality of precoding hypotheses based on the channel estimates; determining a Figure of Merit (FOM) for each of the plurality of precoding hypotheses; determining the precoding information based on the FOM for each of the plurality of precoding hypotheses; performing matched filtering of received reference symbols and corresponding known reference symbols; filtering an output of the matched filtering based on a plurality of precoding hypotheses; applying a transform to the filtered output for the plurality of precoding hypotheses to produce a plurality of transformed precoding hypotheses; calculating a FOM for each of the plurality of transformed precoding hypotheses; and selecting a precoder that maximizes the FOM as the precoding information. ### Claim 2 (depends on 1) The method of claim 1, wherein the matched filtering is performed with at least one of the group consisting of: a Sounding Reference Signal (SRS), a Random Access Channel(RACH), Demodulation Reference Signals (DMRS), a Channel State Information Reference Signal(CSI-RS), Physical Uplink Control Channel (PUCCH), and DMRS for PUCCH. ### Claim 3 (depends on 2) The method of claim 2, wherein the matched filtering is performed with the SRS and a Zadoff-Chu sequence inverted. ### Claim 4 (depends on 1) The method of claim 1, wherein the plurality of precoding hypotheses are chosen from at least one of the group consisting of: a codebook, a Grid of Beams (GoB) codebook, a New Radio (NR) Type 1 codebook, an NR Type 2 codebook, and a subset of any of these codebooks. ### Claim 5 (depends on 1) The method of claim 1, wherein the transform is chosen from the group consisting of: a Discrete Fourier Transform (DFT), an Inverse DFT, a Discrete Cosine Transform (DCT), and an Inverse DCT. ### Claim 6 (depends on 1) The method of claim 1, wherein the transform is linear. ### Claim 7 (depends on 1) The method of claim 1, wherein the FOM is a maximum. ### Claim 8 (depends on 7) The method of claim 7, wherein the maximum is only performed over a limited range. ### Claim 9 (depends on 8) The method of claim 8, wherein the limited range is related to at least one of the group consisting of: a cyclic prefix and a delay spread of the channel. ### Claim 10 (depends on 1) The method of claim 1, wherein the FOM is proportional to an estimated Signal to Noise Ratio (SNR). ### Claim 11 (depends on 1) The method of claim 1, wherein the radio node is a gNB, and the other device is a wireless device that operates in a NR communication network. ### Claim 12 (depends on 1) The method of claim 1, wherein the radio node is a gNB. ### Claim 13 (depends on 1) The method of claim 1, wherein the radio node is a wireless device that operates in a NR communication network. ### Claim 14 (depends on 1) The method of claim 1, wherein the radio node is a wireless device, and the another device is a gNB. ### Claim 15 (depends on 1) The method of claim 1, wherein the radio node is a base station. ### Claim 16 (depends on 1) The method of claim 1, wherein the radio node is a wireless device. ### Claim 17 A base station for determining precoding information, the base station comprising: one or more processors; and memory comprising instructions to cause the base station to: determine channel estimates for at least a channel between the base station and another device; determine a plurality of precoding hypotheses based on the channel estimates; determine a Figure of Merit (FOM), for each of the plurality of precoding hypotheses; determine the precoding information based on the FOM for each of the plurality of precoding hypotheses; perform matched filtering of received reference symbols and corresponding known reference symbols; filter an output of the matched filtering based on a plurality of precoding hypotheses; apply a transform to the filtered output for the plurality of precoding hypotheses to produce a plurality of transformed precoding hypotheses; calculate a FOM for each of the plurality of transformed precoding hypotheses; and select a precoder that maximizes the FOM as the precoding information. ### Claim 18 A wireless device for determining precoding information, the wireless device comprising: one or more processors; and memory comprising instructions to cause the wireless device to: determine channel estimates for at least a channel between the wireless device and another device; determine a plurality of precoding hypotheses based on the channel estimates; determine a Figure of Merit (FOM), for each of the plurality of precoding hypotheses; determine the precoding information based on the FOM for each of the plurality of precoding hypotheses; perform matched filtering of received reference symbols and corresponding known reference symbols; filter an output of the matched filtering based on a plurality of precoding hypotheses; apply a transform to the filtered output for the plurality of precoding hypotheses to produce a plurality of transformed precoding hypotheses; calculate a FOM for each of the plurality of transformed precoding hypotheses; and select a precoder that maximizes the FOM as the precoding information.