QC-LDPC Puncturing Structure for 7/8 Wireless Code Rates
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Solution Overview
Problem
Existing wireless communication systems face challenges in achieving higher code rates and throughput due to limitations in LDPC codeword lengths and code rates, particularly in IEEE 802.11 standards, which are not optimized for modern wireless signaling capabilities.
Innovation Solution
Puncturing specific bits from LDPC codewords, such as systematic and parity bits, to achieve higher code rates like 7/8, while using optimized LDPC codes that enhance parity bit generation for improved coding gains and flexibility, allowing for larger codeword lengths without significant hardware modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC codeword length is increased to improve coding gains, then error correction performance is improved, but hardware complexity and storage requirements increase
Solution Approach 1:
The parity-check matrix H is segmented into multiple sub-matrices (first sub-matrix, second sub-matrix, third sub-matrix, fourth sub-matrix) with specific structures. This segmentation allows the decoder to process different segments independently or in parallel, reducing the computational complexity of handling the full matrix while maintaining the coding gains of the complete structure.
Solution Approach 2:
The patent employs a nested structure where the parity-check matrix contains sub-matrices that are themselves structured with nested patterns. The first sub-matrix contains a first sub-sub-matrix, and this nesting continues, allowing hierarchical processing that reduces storage requirements while preserving the error correction capabilities of the full matrix structure.
2Productivity
If code rate is increased to improve throughput, then data transmission efficiency is improved, but error correction capability deteriorates
Solution Approach 1:
The patent changes the parameters of the parity-check matrix by defining specific structures for its sub-matrices with different densities and patterns. By adjusting the parameters of these sub-matrices (such as the density of non-zero elements and their positions), the code rate can be optimized while maintaining sufficient error correction capability through the carefully designed matrix structure.
3Productivity
If LDPC code structure is optimized for higher code rates, then throughput is improved, but compatibility with existing hardware increases complexity
Solution Approach 1:
The parity-check matrix structure is designed to be universal and multi-functional, accommodating different code rates and codeword lengths while maintaining the same fundamental decoding architecture. The segmented sub-matrix structure can be configured for various operational modes, allowing existing hardware to support multiple throughput levels without requiring complete redesign for each code rate optimization.
Data Source
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AI summary
This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for encoding data for wireless transmissions. In one aspect, a wireless device may encode a number (M) of systematic bits for transmission to a receiving device. The systematic bits may be encoded using a quasi-cyclic low-density parity-check (QC-LDPC) code to produce an LDPC codeword. The LDPC codeword may include a number (N) of codeword bits, including the M systematic bits and one or more parity bits. The wireless device may further puncture a number (K) of the codeword bits (systematic and/or parity bits) to produce a punctured codeword having a code rate M/(N-K) > 5/6, e.g M/(N-K) = 7/8. The wireless device may transmit the N-K remaining codeword bits, over a wireless channel, to a receiving device.