Polar CRC Encoding with Reliability-Based Bit Selection
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Solution Overview
Problem
Conventional polar code concatenation with CRC codes does not achieve optimal performance, especially when the CRC code length is short, leading to suboptimal frame error rates in wireless communications systems.
Innovation Solution
The method involves selecting bits for CRC encoding based on row weights and reliability of polarized subchannels, and performing polar encoding on both CRC check bits and input bits to generate an encoded codeword, thereby improving the performance of the polar code concatenated with CRC codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polar code concatenation with CRC codes is used, then the encoding structure is simple, but the frame error rate performance is suboptimal
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different bit positions. Specifically, information bits are divided into two groups: those that participate in CRC encoding and those that do not. The CRC encoding is selectively applied to specific information bits based on their position and reliability characteristics, rather than uniformly to all bits. This selective local application of CRC encoding improves frame error rate performance while avoiding the complexity of applying CRC to all bits uniformly.
Solution Approach 2:
The patent segments the information bits into distinct groups based on their encoding characteristics. The K information bits are divided into those that will be CRC-encoded (M bits) and those that will not. This segmentation allows the system to apply different encoding strategies to different subsets of bits, optimizing the overall error performance without requiring a complete redesign of the encoding structure.
2Reliability
If CRC encoding is applied to all K bits, then error detection capability is maximized, but encoding complexity and overhead increase
Solution Approach 1:
The patent implements partial action by applying CRC encoding to only M out of K information bits, rather than to all K bits. This selective partial application provides sufficient error detection capability for the most critical bits while avoiding the unnecessary complexity and overhead of CRC encoding on all bits. The number M is carefully chosen to achieve the desired performance level with minimal complexity.
Solution Approach 2:
Different encoding treatments are applied to different portions of the information bits. Specifically, M bits are selected to participate in CRC encoding while the remaining K-M bits are encoded differently. This local differentiation optimizes the balance between error detection capability and encoding complexity by applying the more complex CRC operation only where most beneficial.
Data Source
AI summary
A method and an apparatus for encoding a polar code concatenated with a cyclic redundancy check (CRC), where M bits are selected from K bits in the sequence to perform CRC encoding. The M bits are determined based on reliability of K polarized subchannels on which the K bits are placed and/or row weights of K rows, in a first matrix, corresponding to the K polarized subchannels on which the K bits are placed. The first matrix is an encoding matrix of polar encoding. Polar encoding is performed on the K bits and obtained CRC check bits. An encoded codeword is output.