LDPC Bit Replacement to Preserve Amplitude Shaping Gains
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems using low density parity check (LDPC) encoding face challenges in maintaining the gains provided by amplitude shaping processes due to puncturing of information bit vectors, which reduces communication quality.
Innovation Solution
A preprocessing technique is applied at a wireless device to replace information bit vectors with corresponding parity bit vectors before encoding, avoiding puncturing and ensuring that information bits are generated at parity bit columns of the parity check matrix, while a postprocessing technique is used at the receiving device to replace parity bits with information bits after decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If puncturing is applied to information bit vectors in LDPC encoding, then communication efficiency is improved, but communication quality deteriorates due to loss of amplitude shaping gains
Solution Approach 1:
The patent extracts the harmful effect of puncturing by separating the information bit generation function from the transmission process. Instead of puncturing information bits, the system generates information bits at parity bit columns through preprocessing, thereby removing the source of quality degradation while preserving coding efficiency
Solution Approach 2:
The patent applies preprocessing before encoding to replace information bits with parity bits at specific positions. This preliminary action ensures that information bits are generated at parity bit columns during encoding, preventing the need for puncturing and preserving amplitude shaping gains throughout the transmission process
2Device complexity
If information bits are generated at parity bit columns without preprocessing, then encoding simplicity is maintained, but amplitude shaping gains are lost due to puncturing
Solution Approach 1:
The patent introduces a preprocessing step before encoding that replaces information bits with parity bits at designated positions. This preliminary preparation enables the encoder to generate information bits at parity bit columns naturally, preserving amplitude shaping gains without complicating the core encoding process
Solution Approach 2:
The patent introduces a preprocessing component as an intermediary between the information source and the LDPC encoder. This intermediary performs bit replacement to ensure that information bits are positioned at parity bit columns, thereby preserving amplitude shaping gains while maintaining encoder simplicity
3Reliability
If bit replacement preprocessing is applied, then communication quality is improved, but processing complexity increases
Solution Approach 1:
The patent extracts the complex bit replacement operation from the main encoding and decoding paths, implementing it as a separate preprocessing and postprocessing stage. This separation confines complexity to specific stages while keeping the core LDPC operations simple and efficient
Solution Approach 2:
The patent discards the original information bits at certain positions during preprocessing and recovers them through postprocessing after decoding. This approach allows quality improvement through bit replacement while managing complexity by limiting the replacement operation to specific preprocessing and postprocessing stages
Data Source
AI summary
Methods, systems, and devices for wireless communication are described to support replacing values of one or more information bit vectors with one or more corresponding sets of parity bits. A first wireless device may replace an information bit vector with a parity bit vector, using a set of information bits of the information bit vector and based on a parity check matrix, which may result in generating the set of information bits at an information bit vector corresponding to a parity bit column of the parity check matrix, during encoding. The first wireless device may perform a transmission to a second wireless device, which may receive the transmission, decode the set of information bits to the information bit vector corresponding to the parity bit column. The second wireless device may replace other bit estimates of a vector corresponding to an information bit column with the set of information bits.