Layered LDPC Decoder Early Termination for Fewer Pipeline Delays
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently decoding low-density parity-check (LDPC) codes, particularly in high-speed data transmission and storage, where errors can lead to unusable data and require retransmissions, and existing solutions do not effectively manage memory conflicts and pipeline delays in layered LDPC decoders.
Innovation Solution
The implementation of early termination techniques for LDPC decoders, which determine when to terminate the decoding process by tracking sign flips and parity check results, and modifying the layered decoding algorithm to relax dependencies between bit LLR updates and a posteriori LLR computations, thereby reducing pipeline bubbles and memory conflicts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If layered LDPC decoding is implemented to improve decoding speed, then productivity increases, but memory conflicts and pipeline delays increase
Solution Approach 1:
The patent applies preliminary action by checking parity conditions and detecting sign flips of log-likelihood ratios (LLRs) during the decoding process to determine early termination. By performing these checks in advance and during intermediate stages, the decoder can terminate before completing all scheduled iterations when the code word is already correctly decoded, thus reducing pipeline delays while maintaining high decoding speed
Solution Approach 2:
The patent implements dynamics by making the decoding process adaptive through early termination capability. The number of iterations is not fixed but dynamically adjusted based on real-time detection of sign flips and parity check results. This allows the system to optimize between maximum speed (early termination) and maximum reliability (full iterations) depending on the actual decoding state
2Reliability
If iterative decoding is performed to improve reliability, then error correction capability increases, but the number of iterations increases causing time loss
Solution Approach 1:
The patent applies feedback by continuously monitoring the sign flip status of LLRs and parity check results during each iteration. This feedback mechanism allows the decoder to assess decoding progress and make informed decisions about termination. When no sign flips occur and parity checks pass, the feedback indicates successful decoding, allowing early termination without compromising error correction capability
Solution Approach 2:
By performing preliminary checks of sign flips and parity conditions during the decoding process, the system can determine in advance whether additional iterations are necessary. This preliminary assessment prevents unnecessary iterations, reducing time loss while maintaining the reliability needed for proper error correction
3Productivity
If early termination is implemented to reduce iterations, then productivity increases, but decoding accuracy may deteriorate
Solution Approach 1:
The patent uses feedback from sign flip detection and parity check results to ensure decoding accuracy before termination. The continuous monitoring of LLR sign changes provides feedback on convergence status, and parity check feedback verifies code word validity. Only when both feedback indicators confirm successful decoding does the system terminate early, thus maintaining decoding accuracy while improving productivity
Solution Approach 2:
The patent performs preliminary verification of decoding success through sign flip detection and parity checks before terminating. This preliminary action ensures that early termination does not compromise accuracy by confirming the code word is correctly decoded before stopping the iteration process
Data Source
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AI summary
Certain aspects of the present disclosure generally relate to methods and apparatus for layered decoding of low density parity check (LDPC) codes, and more particularly to early termination techniques for low-density parity-check (LDPC) layered decoder architecture.