Cascaded Polar-LDPC Encoding for Flexible Code Length Extension
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Solution Overview
Problem
Polar codes face limitations in flexible extension of code length, restricting their application in data channels due to difficulties in extending the code length effectively.
Innovation Solution
An encoding method that involves obtaining a first bit sequence and performing channel encoding to generate a third bit sequence with additional check bits, allowing for flexible extension of code length based on the target code length M, using an extension matrix derived from a lifted base matrix to incorporate check bits and maintain the advantages of polar codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polar code is used for channel encoding, then algebraic encoding structure and probability decoding advantages are achieved, but code length extension flexibility is poor
Solution Approach 1:
The encoding process is segmented into two independent stages: first channel encoding (polar code) and second channel encoding (LDPC code). This segmentation allows each encoding stage to maintain its own advantages while combining to achieve overall flexibility. The first bit sequence undergoes polar code encoding to preserve algebraic structure and decoding efficiency, while the second bit sequence undergoes LDPC encoding to enable flexible code length extension through check bit generation.
Solution Approach 2:
The patent merges polar code encoding and LDPC code encoding into a unified two-stage encoding system. The output of the first channel encoder becomes the input to the second channel encoder, creating a cascaded structure that combines the strengths of both coding schemes. This merging allows the system to simultaneously achieve the reliability benefits of polar codes and the flexibility benefits of LDPC codes.
2Adaptability or versatility
If code length is extended using check bits, then flexibility of code length extension is improved, but device complexity increases
Solution Approach 1:
The system dynamically adjusts the code length by varying the number of check bits E based on the target code length M and the intermediate code length N. The extension matrix dimensions (N rows and E columns) are dynamically determined to achieve the desired code length M = N + E. This dynamic adjustment mechanism provides flexibility without requiring a completely different encoding structure for each code length.
Solution Approach 2:
The extension matrix serves as an intermediary component that bridges the fixed-structure polar code output and the flexible code length requirement. By introducing this intermediate encoding stage with a specifically designed extension matrix, the system can transform the rigid polar code structure into a flexible final code structure with extended length, without directly modifying the core polar encoding algorithm.
Data Source
AI summary
This application discloses an encoding method, a decoding method, and an apparatus. The encoding method includes: obtaining a first bit sequence and a target code length M; then performing first channel encoding on the first bit sequence, to obtain a second bit sequence; performing second channel encoding based on the second bit sequence, to obtain a third bit sequence; and outputting the third bit sequence. The first bit sequence includes K information bits, the second bit sequence includes N bits, and the third bit sequence includes the N bits and E check bits, where M>N, and E=M−N. M, K, N, and E are all integers greater than or equal to 1.