Polar Code Rate Matching Using Adaptive Mother Code Selection
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Solution Overview
Problem
Existing rate matching methods for polar codes in communication systems face challenges in reducing complexity and achieving efficient encoding and decoding, particularly when adjusting code lengths, which results in high overheads and increased complexity with larger mother code lengths.
Innovation Solution
A method that determines the appropriate mother code length based on the target code length, using either repetition or shortening/puncturing techniques to achieve the desired code length, while optimizing for integer powers of 2, thereby reducing encoding and decoding complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mother code length larger than the target code length is used for polar encoding, then encoding gain is improved, but complexity and buffer size increase
Solution Approach 1:
The patent applies dynamics by making the mother code length adjustable based on the target code length. Instead of always using a fixed large mother code length, the system dynamically selects the appropriate mother code length (N1 or N2) according to the specific transmission requirements, thereby adapting the encoding complexity to the actual needs while maintaining encoding gain where necessary.
Solution Approach 2:
The patent changes the parameter of mother code length from a fixed value to a variable that can be selected from different powers of 2. By changing this parameter based on the target code length and transmission conditions, the system optimizes the balance between encoding gain and complexity, avoiding unnecessary computational overhead when large mother codes are not required.
2Reliability
If a mother code length larger than the target code length is used for polar encoding, then encoding gain is improved, but buffer size increases
Solution Approach 1:
The patent changes the mother code length parameter to match or exceed the target code length only when necessary. By selecting from multiple possible mother code lengths (different powers of 2), the system minimizes the buffer size required while maintaining sufficient encoding gain, avoiding the need to always allocate buffers for very large mother codes when smaller ones suffice.
3Adaptability or versatility
If rate matching is performed by puncturing or shortening a large mother code, then target code length is achieved, but overhead increases
Solution Approach 1:
The patent applies preliminary action by pre-selecting an appropriate mother code length before encoding, rather than starting with a large mother code and then puncturing or shortening it. This preliminary selection avoids the overhead associated with rate matching operations, as the encoding is performed directly at or near the target code length from the beginning.
4Reliability
If the target code length increases, then code rate decreases and encoding gain increases, but complexity increases
Solution Approach 1:
The patent applies dynamics by making the mother code length adaptable to the target code length. When the target code length increases, the system dynamically selects a larger mother code length from available powers of 2, but only to the extent necessary. This dynamic adaptation allows the system to maintain encoding gain for longer codes while avoiding the complexity increase that would result from always using the largest possible mother codes.
Data Source
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AI summary
Embodiments of this application provide a coding method, a coding apparatus, a communication apparatus, a decoding method, a device and a computer readable storage medium. The method includes: obtaining an information bit sequence and a target code length M of a polar code, a quantity of information bits in the information bit sequence is K, wherein K, M are positive integers; when the target code length M meets a preset condition, using a polar code with a first mother code length N1 to encode the information bit sequence, to output a first encoded bit sequence having a length of N1, wherein N1=2n and n is an integer less than or equal to log2M; and performing rate matching by repeating at least some bits in the first encoded bit sequence, to obtain a first target polar code with a length M; wherein the preset condition comprises one of: a first code rate R1 is less than or equal to a second code rate R2 that is preset, wherein the first code rate R1 is equal to K/ N1; or a difference between the target code length M and the first mother code length N1 is less than a predetermined range.