Polar Code Decoder Reliability Estimation for SCL Bit Flipping
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Solution Overview
Problem
Conventional polar code decoders face challenges in selecting the optimal bit position to flip during the successive cancellation list (SCL) flip operation, leading to inefficiencies in decoding and increased average decoding times.
Innovation Solution
A method and polar code decoder that estimates the correct path probability and reliability of each bit position in the decoding tree, allowing for the selection of the most suitable bit position to flip, thereby improving decoding efficiency by performing an SCL flip operation based on these calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional SCL flip operation is performed without reliable bit position selection, then decoding can be attempted, but the decoding efficiency is low and average decoding time is increased
Solution Approach 1:
The patent performs preliminary reliability estimation for all bit positions before executing the flip operation. By calculating path metrics and determining reliability values in advance, the system identifies the most suitable bit position to flip, avoiding trial-and-error approaches and reducing the average number of flip operations needed.
Solution Approach 2:
The decoding system uses its own decoded results and path metrics to automatically determine the reliability of each bit position. This self-evaluation mechanism allows the system to autonomously select the optimal flip target without external intervention, improving decoding efficiency while maintaining accuracy.
2Measurement precision
If reliability estimation is performed for each bit position, then the selection of to-be-flipped bit position becomes accurate, but the computational complexity increases
Solution Approach 1:
The patent performs reliability estimation for all bit positions (excessive action) to ensure accurate identification of the optimal flip target. By comprehensively evaluating all positions rather than using heuristic selection, the system achieves high selection accuracy that significantly reduces the number of flip operations required, offsetting the additional computational cost.
Solution Approach 2:
The system uses feedback from path metrics and decoding results to continuously refine bit position reliability estimates. This feedback mechanism allows the decoder to learn from previous decoding attempts and improve its selection accuracy over time, making the computational investment in reliability estimation increasingly worthwhile.
Data Source
AI summary
The disclosure provides a method and a polar code decoder for determining a to-be-flipped bit position when performing a successive cancellation list flip operation. The method includes: obtaining a polar code decoding tree generated by performing a successive cancellation list (SCL) operation on a polar code segment, and the polar code segment includes multiple bit positions, and each bit position in the polar code decoding tree includes multiple surviving paths and multiple pruned paths; in a post-processing stage for the SCL operation, estimating a correct path probability of each of the surviving paths and the pruned paths of the i-th bit position and accordingly estimating a reliability for the i-th bit position; selecting a specific bit position among the bit positions based on the reliability of each bit position; and performing an SCL flip operation on the polar code decoding tree based on the specific bit position.