Long LDPC Code Layout for Fixed 1344-Bit 7/8 Codewords
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The implementation of different LDPC codeword lengths for various code rates in wireless networks, such as in the IEEE 802.11ay standard, leads to inefficiencies in blocking and de-blocking processes at transmitters and receivers, particularly for the 7/8 LDPC code rate, which results in increased redundancy and complexity during encoding and single carrier blocking.
Innovation Solution
A high rate, long LDPC code with a codeword length of 1344 bits is developed, maintaining consistency with lower rate codes, by deriving a parity check matrix HI through optimized lifting and summation of base parity check matrices, specifically for the 7/8 code rate, thereby simplifying encoding and reducing redundancy in single carrier blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different LDPC codeword lengths are used for different code rates, then code rate adaptability is improved, but blocking and de-blocking process complexity increases
Solution Approach 1:
The patent applies homogeneity by using a uniform codeword length of 1344 bits across all LDPC code rates (1/2, 5/8, 3/4, 7/8, 13/16). This is achieved through a systematic generator matrix construction method that produces consistent codeword lengths regardless of code rate, thereby simplifying blocking and de-blocking processes while maintaining code rate adaptability.
2Adaptability or versatility
If different LDPC codeword lengths are used for different code rates, then code rate adaptability is improved, but redundancy in encoding increases
Solution Approach 1:
The patent changes the parameter of codeword length from variable (different for each code rate) to fixed (1344 bits for all code rates). This is accomplished through a modified generator matrix construction that adjusts the information bit and parity bit distribution according to code rate while maintaining constant total codeword length, thereby reducing encoding redundancy.
3Adaptability or versatility
If different LDPC codeword lengths are used for different code rates, then code rate adaptability is improved, but spectrum efficiency decreases
Solution Approach 1:
The patent optimizes the distribution of information bits and parity bits within the fixed 1344-bit codeword structure according to different code rates. This parameter optimization reduces the need for zero-padding and improves spectral efficiency by maximizing the utilization of available spectrum resources across all code rates.
Data Source
AI summary
Methods and devices for encoding source words and decoding codewords wherein encoding a source word includes: receiving a 1×K source word row vector ū; and generating a 1×N codeword vector c=ū·G, wherein G is a K×N generator matrix derived from a parity check matrix HI; and wherein the parity check matrix HI is derived from a base parity check matrix H by applying an optimized lifting matrix to the base parity check matrix H.