Polar Code Rate Matching With Adaptive Mother Code Length
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Solution Overview
Problem
Polar codes face challenges in rate matching, leading to increased complexity and overhead during encoding and decoding, especially when adjusting code lengths from a mother code to a target code, which affects encoding gain and decoding delays.
Innovation Solution
A method for rate matching in polar codes that involves using a mother code length less than or equal to the target code length and repeating bits to achieve the desired length, or using a mother code length greater than the target code and shortening or puncturing the encoded sequence, based on preset conditions to balance encoding gain and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rate matching is performed by puncturing or shortening a mother code to achieve target code length, then code length flexibility is improved, but encoding and decoding complexity increases
Solution Approach 1:
The patent segments the rate matching process into two distinct approaches: puncturing mode for high code rates and shortening mode for low code rates. This segmentation allows the system to select the appropriate method based on the code rate, thereby reducing overall complexity while maintaining code length flexibility. The encoding apparatus determines the code rate and selects the corresponding rate matching mode, avoiding the need to implement both complex operations in all cases.
2Reliability
If a larger mother code length is used to maintain encoding gain, then error correction performance is improved, but decoding delays increase
Solution Approach 1:
The patent dynamically changes the mother code length parameter based on the target code length and code rate requirements. By selecting an appropriate mother code length from available options (e.g., 512, 1024, 2048 bits) rather than always using the maximum length, the system maintains sufficient encoding gain while reducing decoding delays. The encoding apparatus determines the appropriate mother code length to balance performance and delay requirements.
3Adaptability or versatility
If traditional rate matching methods are used, then code length adjustment is achieved, but overhead increases
Solution Approach 1:
The patent implements self-service rate matching where the encoding apparatus autonomously determines the appropriate rate matching mode (puncturing or shortening) and parameters based on the code rate and target code length, without requiring additional overhead signaling to the decoding apparatus. Both apparatuses share predetermined knowledge of the mapping between code rates and rate matching modes, eliminating the need for extra overhead bits to convey rate matching information.
Data Source
AI summary
Embodiments of the application provide a method for rate matching in a wireless communication network. A device obtains K information bits and a target code length M of a polar code, determines, according to a minimum value of a set of values, a mother code length N1, polar encodes the K information bits to obtain an encoded sequence of N1 bits, obtains a target sequence of M bits from the N1 bit encoded sequence, and outputs the M-bit target sequence. When the mother code length N1 is larger than the target code length M, (N1−M) bits of the encoded sequence are punctured or shortened from the N1 bit encoded sequence.