# US 12,191,884 B2 · Extending low-density parity check (LDPC) codes for Wi-Fi > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,884 B2 - Document ID: US12191884B2 - Status: Granted - Kind: B2 - Application number: 18/189,865 - Filed: 2023-03-24 - Published: 2024-09-26 - Granted: 2025-01-07 - Earliest claimed: 2023-03-24 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Thomas Joseph Richardson; Kanke Wu; Bin Tian; Didier Johannes Richard Van Nee - Web page: https://patentgrep.com/patent/US12191884B2 ## CPC - H03M 13/033: {Theoretical methods to calculate these checking codes} - H03M 13/1174: {Parity-check or generator matrices built from sub-matrices representing known block codes such as, e.g. Hamming codes, e.g. generalized LDPC codes} - H03M 13/116: {Quasi-cyclic LDPC [QC-LDPC] codes, i.e. the parity-check matrix being composed of permutation or circulant sub-matrices} - H03M 13/616: {Matrix operations, especially for generator matrices or check matrices, e.g. column or row permutations} - H03M 13/6516: {Support of multiple code parameters, e.g. generalized Reed-Solomon decoder for a variety of generator polynomials or Galois fields} - H03M 13/6561: {Parallelized implementations} - H04L 1/0057: {Block codes (H04L1/0061, H04L1/0064 take precedence)} - H03M 13/114: {Shuffled, staggered, layered or turbo decoding schedules} - H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract This disclosure provides methods, components, devices and systems for low-density parity check (LDPC) coding. Some aspects more specifically relate to extending LDPC codewords to produce longer codewords. In some examples, a first wireless device may generate a baseline LDPC code by performing a first lifting on a base matrix, which may produce an LDPC code used for a current Wi-Fi implementation. The first wireless device may then perform a second lifting or a re-lifting (such as a cyclic lifting, a product lifting, a swapping lifting, or a combination thereof) to generate an extended lifted code. This extended lifted code may be an extension of the first LDPC code such that the first LDPC code may be preserved as part of the extended code. Then first wireless device may then transmit the extended LDPC code as an extended or lifted codeword. ## Claims ### Claim 1 An apparatus for wireless communication at a first wireless device, comprising: a processing system that includes processor circuitry and memory circuitry that stores code, the processing system configured to cause the first wireless device to: generate a first low-density parity check matrix and a first low-density parity check code by performing a first lifting on a base matrix; generate an extended low-density parity check matrix and an extended low-density parity check code by performing a second lifting on the first low-density parity check matrix, one or more lifted permutation matrices associated with base edges of the first low-density parity check matrix being recoverable as block-wise sub-matrices of the one or more lifted permutation matrices associated with respective base edges of the extended low-density parity check matrix, the extended low-density parity check code being an extension of the first low-density parity check code; encode a first plurality of bits according to the extended low-density parity check matrix and the extended low-density parity check code to produce a lifted codeword; and transmit, at the first wireless device, the lifted codeword to a second wireless device. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the extended low-density parity check matrix comprises a two-step lifting that includes a first lifting step and a second lifting step, the second lifting step applied to a result of the first lifting step to produce an extended lifting, and the processing system is further configured to cause the first wireless device to: generate an integer pair to identify one or more images of first low-density parity check lifted bit vectors within respective extended lifted low-density parity check bit vectors, a first integer of the integer pair corresponding to the first lifting step and a second integer of the integer pair corresponding to the second lifting step, and bits of a first low-density parity check lifted bit vector of an extended low-density parity check lifted bit vector are enumerated first according to the first integer of the integer pair identifying a bit within the first low-density parity check lifted bit vector and second according to the second integer of the integer pair identifying an image of the first low-density parity check lifted bit vector within the extended low-density parity check lifted bit vector; and perform the first lifting step and the second lifting step in accordance with an inner extension or an outer extension of the first lifting to produce the extended low-density parity check code. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the second lifting step comprises the inner extension that retains first low-density parity check liftings as a sub-component of extended low-density parity check liftings in accordance with the first lifting being recoverable from the second lifting via an application of a bit mask. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein the second lifting step comprises the outer extension that retains first low-density parity check liftings as a sub-component of extended low-density parity check liftings in accordance with the first lifting being recoverable from the second lifting via an application of a modulo operation. ### Claim 5 (depends on 2) The apparatus of claim 2, wherein the first lifting step is related to the second lifting step via a lifting factor and a modulo operation. ### Claim 6 (depends on 2) The apparatus of claim 2, wherein the inner extension retains lifted edge permutations of the first low-density parity check code as a sub-component of edge permutations of the extended low-density parity check code in accordance with a first lifting permutation being recoverable from an extended lifting permutation as a block-wise sub-matrix of the extended low-density parity check matrix. ### Claim 7 (depends on 2) The apparatus of claim 2, wherein the first lifting corresponding to the first integer of the integer pair is independent from the second lifting corresponding to the second integer of the integer pair in accordance with the inner extension, and the block-wise sub-matrices corresponding to a permutation of an image of the first lifting are identical. ### Claim 8 (depends on 2) The apparatus of claim 2, wherein the processing system is further configured to cause the first wireless device to: swap at least two images of the one or more images of the first low-density parity check code during the first lifting step or the second lifting step. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the extended low-density parity check code comprises one or more lifted low-density parity check codes including at least the first low-density parity check code that is recoverable from the extended low-density parity check code. ### Claim 10 A method for wireless communication at a first wireless device, comprising: generating a first low-density parity check matrix and a first low-density parity check code by performing a first lifting on a base matrix; generating an extended low-density parity check matrix and an extended low-density parity check code by performing a second lifting on the first low-density parity check matrix, one or more lifted permutation matrices associated with base edges of the first low-density parity check matrix being recoverable as block-wise sub-matrices of the one or more lifted permutation matrices associated with respective base edges of the extended low-density parity check matrix, the extended low-density parity check code being an extension of the first low-density parity check code; encoding a first plurality of bits according to the extended low-density parity check matrix and the extended low-density parity check code to produce a lifted codeword; and transmitting, at the first wireless device, the lifted codeword to a second wireless device. ### Claim 11 (depends on 10) The method of claim 10, wherein the extended low-density parity check matrix comprises a two-step lifting that includes a first lifting step and a second lifting step, the second lifting step applied to a result of the first lifting step to produce an extended lifting, the method further comprising: generating an integer pair to identify one or more images of first low-density parity check lifted bit vectors within respective extended lifted parity check bit vectors, a first integer of the integer pair corresponding to the first lifting step and a second integer of the integer pair corresponding to the second lifting step, and bits of a first low-density parity check lifted bit vector of an extended low-density parity check lifted bit vector are enumerated first according to the first integer of the integer pair identifying a bit within the first low-density parity check lifted bit vector and second according to the second integer of the integer pair identifying an image of the first low-density parity check lifted bit vector within the extended low-density parity check lifted bit vector; and performing the first lifting step and the second lifting step in accordance with an inner extension or an outer extension of the first lifting to produce the extended low-density parity check code. ### Claim 12 (depends on 11) The method of claim 11, wherein the second lifting step comprises the inner extension that retains first low-density parity check liftings as a sub-component of extended low-density parity check liftings in accordance with the first lifting being recoverable from the second lifting via an application of a bit mask. ### Claim 13 (depends on 11) The method of claim 11, wherein the second lifting step comprises the outer extension that retains first low-density parity check liftings as a sub-component of extended low-density parity check liftings in accordance with the first lifting being recoverable from the second lifting via an application of a modulo operation. ### Claim 14 (depends on 11) The method of claim 11, wherein the first lifting step is related to the second lifting step via a lifting factor and a modulo operation. ### Claim 15 (depends on 11) The method of claim 11, wherein the inner extension retains lifted edge permutations of the first low-density parity check code as a sub-component of edge permutations of the extended low-density parity check code in accordance with a first lifting permutation being recoverable from an extended lifting permutation as a block-wise sub-matrix of the extended low-density parity check matrix. ### Claim 16 (depends on 11) The method of claim 11, wherein the first lifting corresponding to the first integer of the integer pair is independent from the second lifting corresponding to the second integer of the integer pair in accordance with the inner extension, and the block-wise sub-matrices corresponding to a permutation of an image of the first lifting are identical. ### Claim 17 (depends on 11) The method of claim 11, further comprising: swapping at least two images of the one or more images of the first low-density parity check code during the first lifting step or the second lifting step. ### Claim 18 (depends on 10) The method of claim 10, wherein the extended low-density parity check code comprises one or more lifted low-density parity check codes including at least the first low-density parity check code that is recoverable from the extended low-density parity check code. ### Claim 19 An apparatus for wireless communication at a first wireless device, comprising: a processing system that includes processor circuitry and memory circuitry that stores code, the processing system configured to cause the first wireless device to: generate a first low-density parity check matrix and a first low-density parity check code by performing a first lifting on a base matrix; generate an extended low-density parity check matrix and an extended low-density parity check code by performing a second lifting on the first low-density parity check matrix, one or more lifted permutation matrices associated with base edges of the first low-density parity check matrix being recoverable as block-wise sub-matrices of the one or more lifted permutation matrices associated with respective base edges of the extended low-density parity check matrix, the extended low-density parity check code being an extension of the first low-density parity check code; receive, from a second wireless device, a lifted codeword encoded in accordance with the extended low-density parity check matrix; and decode the lifted codeword according to the extended low-density parity check code. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the extended low-density parity check matrix comprises a two-step lifting that includes a first lifting step and a second lifting step, the second lifting step applied to a result of the first lifting step to produce an extended lifting, and the processing system is further configured to cause the first wireless device to: generate an integer pair to identify one or more images of first low-density parity check lifted bit vectors within respective extended lifted low-density parity check bit vectors, a first integer of the integer pair corresponding to the first lifting step and a second integer of the integer pair corresponding to the second lifting step, and bits of a first low-density parity check lifted bit vector of an extended low-density parity check lifted bit vector are enumerated first according to the first integer of the integer pair identifying a bit within the first low-density parity check lifted bit vector and second according to the second integer of the integer pair identifying an image of the first low-density parity check lifted bit vector within the extended low-density parity check lifted bit vector; and decode the lifted codeword in accordance with the first lifting step and the second lifting step in accordance with an inner extension or an outer extension. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein the processing system is further configured to cause the first wireless device to: decode the lifted codeword in accordance with the inner extension, the inner extension retaining a first low-density parity check lifting permutation identifier as a sub-component of an extended low-density parity check lifting permutation identifier in accordance with the first low-density parity check lifting permutation identifier being recoverable from the extended low-density parity check lifting permutation identifier via an application of a bit mask. ### Claim 22 (depends on 20) The apparatus of claim 20, wherein the processing system is further configured to cause the first wireless device to: decode the lifted codeword in accordance with the outer extension, the outer extension retaining first low-density parity check lifting permutation identifiers as sub-components of extended low-density parity check lifting permutation identifiers in accordance with a first low-density parity check lifting permutation identifier being recoverable from an extended low-density parity check lifting permutation identifier via an application of a modulo operation. ### Claim 23 (depends on 20) The apparatus of claim 20, wherein the first lifting step is related to the second lifting step via a lifting factor and a modulo operation. ### Claim 24 (depends on 20) The apparatus of claim 20, wherein the inner extension retains lifted edge permutations of the first low-density parity check code as a sub-component of edge permutations of the extended low-density parity check code in accordance with a first lifting permutation being recoverable from an extended lifting permutation as a block-wise sub-matrix of the extended low-density parity check matrix. ### Claim 25 (depends on 20) The apparatus of claim 20, wherein the first lifting corresponding to the first integer of the integer pair is independent from the second lifting corresponding to the second integer of the integer pair in accordance with the inner extension, and the block-wise sub-matrices corresponding to a permutation of an image of the first lifting are identical. ### Claim 26 (depends on 20) The apparatus of claim 20, wherein the processing system is further configured to cause the first wireless device to: swap at least two images of the one or more images of the first low-density parity check code during the first lifting step or the second lifting step. ### Claim 27 (depends on 20) The apparatus of claim 20, wherein the extended low-density parity check code comprises one or more lifted low-density parity check codes including at least the first low-density parity check code that is recoverable from the extended low-density parity check code. ### Claim 28 A method for wireless communication at a first wireless device, comprising: generating a first low-density parity check matrix and a first low-density parity check code by performing a first lifting on a base matrix; generating an extended low-density parity check matrix and an extended low-density parity check code by performing a second lifting on the first low-density parity check matrix, one or more lifted permutation matrices associated with base edges of the first low-density parity check matrix being recoverable as block-wise sub-matrices of the one or more lifted permutation matrices associated with respective base edges of the extended low-density parity check matrix, the extended low-density parity check code being an extension of the first low-density parity check code; receiving, from a second wireless device, a lifted codeword encoded via the extended low-density parity check matrix; and decoding the lifted codeword according to the extended low-density parity check code. ### Claim 29 (depends on 28) The method of claim 28, wherein the extended low-density parity check matrix comprises a two-step lifting that includes a first lifting step and a second lifting step, the second lifting step applied to a result of the first lifting step to produce an extended lifting, the method further comprising: generating an integer pair to identify one or more images of first low-density parity check lifted bit vectors within respective extended lifted low-density parity check bit vectors, a first integer of the integer pair corresponding to the first lifting step and a second integer of the integer pair corresponding to the second lifting step, and bits of a first low-density parity check lifted bit vector of an extended low-density parity check lifted bit vector are enumerated first according to the first integer of the integer pair identifying a bit within the first low-density parity check lifted bit vector and second according to the second integer of the integer pair identifying an image of the first low-density parity check lifted bit vector within the extended low-density parity check lifted bit vector; and decoding the lifted codeword in accordance with the first lifting step and the second lifting step in accordance with an inner extension or an outer extension. ### Claim 30 (depends on 29) The method of claim 29, further comprising: decoding the lifted codeword in accordance with the inner extension, the inner extension retaining a first low-density parity check lifting permutation identifier as a sub-component of an extended low-density parity check lifting permutation identifier in accordance with the first low-density parity check lifting permutation identifier being recoverable from the extended low-density parity check lifting permutation identifier via an application of a bit mask.