Polar Code Rate Matching That Preserves Reliability Order
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Solution Overview
Problem
The natural order-based rate matching scheme for polar codes causes changes in reliability order, leading to poor decoding performance and the formation of 'bad points' where SNR suddenly increases, affecting encoding efficiency.
Innovation Solution
A polar code encoding method that determines a threshold based on the length of the reliability sequence and encoded bit sequence to identify sub-sequences for information bits, using methods like puncturing or shortening to improve encoding performance by avoiding these 'bad points'.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a natural order-based rate matching scheme is used, then implementation is simple and both shortened bits and punctured bits are consecutive, but decoding performance deteriorates due to changes in reliability order and formation of bad points
Solution Approach 1:
The patent segments the bit sequence into different parts (information bits and frozen bits) and applies different processing methods to each segment. Specifically, it divides the N bits into K information bits and N-K frozen bits, and further segments the information bits into segments that are punctured or shortened based on the rate matching ratio, thereby maintaining reliability order while achieving simple implementation.
Solution Approach 2:
The patent changes the parameters of the rate matching process by dynamically adjusting which bits are punctured or shortened based on the rate matching ratio R. It modifies the reliability sequence parameters to ensure that after rate matching, the reliability order is preserved, thus improving decoding performance while keeping the implementation straightforward.
2Productivity
If rate matching is performed without considering reliability order changes, then processing is straightforward, but sudden SNR increases occur forming bad points that affect encoding efficiency
Solution Approach 1:
The patent performs preliminary actions by pre-determining which bits will be punctured or shortened based on the rate matching ratio before actual encoding. It calculates the required number of punctured or shortened bits in advance and applies these operations systematically to maintain reliability order, thereby preventing sudden SNR increases and avoiding bad points that would harm decoding performance.
Data Source
AI summary
This application provides a polar code encoding method and an apparatus. The method includes: determining a threshold based on a length N of a first reliability sequence and a length M of an encoded bit sequence, where N is a positive integer power of 2, and M is a positive integer; determining a first sub-sequence and a second sub-sequence based on a rate matching method of the encoded bit sequence and the first reliability sequence; determining, based on the threshold, the first sub-sequence, the second sub-sequence, the rate matching method of the encoded bit sequence, and the first reliability sequence, K information bits corresponding to the encoded bit sequence, where K is a positive integer less than M; and performing polar encoding to obtain the encoded bit sequence.