LDPC Rate Matching with Non-Uniform Redundancy Version Spacing
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Solution Overview
Problem
Existing rate matching methods for LDPC codes in wireless communications systems result in poor HARQ performance, particularly due to uniform distribution of redundancy versions in circular buffers, which affects decoding performance and reliability.
Innovation Solution
The method involves determining a starting position k0 in a buffer sequence W for an output bit sequence, ensuring non-uniform distribution of redundancy versions, thereby reducing repeated bits and improving decoding performance by selecting output bits based on specific intervals and intervals between adjacent values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform distribution of redundancy versions is used in circular buffer, then rate matching can be performed, but HARQ performance deteriorates due to poor decoding performance
Solution Approach 1:
The patent applies asymmetry by changing from uniform distribution to non-uniform distribution of redundancy versions in the circular buffer. Different redundancy versions are placed at different intervals rather than uniformly spaced positions, creating an asymmetric pattern that improves decoding performance while maintaining rate matching functionality.
Solution Approach 2:
The patent implements local quality by making different parts of the circular buffer have different properties. Specifically, different redundancy versions are positioned at different locations with different intervals between them, allowing each region to contribute differently to the overall HARQ performance based on its local characteristics.
2Productivity
If existing rate matching method is used, then bit sequence can be selected and transmitted, but repeated bits increase reducing decoding efficiency
Solution Approach 1:
The patent applies parameter changes by modifying the distribution parameters of redundancy versions in the circular buffer. By changing from uniform spacing to non-uniform spacing with different intervals, the patent reduces the quantity of repeated bits and improves decoding efficiency without changing the fundamental rate matching process.
Data Source
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AI summary
This application discloses an information processing method, an apparatus, a communications device, and a communications system. The communications device is configured to: obtain a starting position in a buffer sequence W for an output bit sequence, and determine the output bit sequence from the buffer sequence W based on the starting position, where a value of the starting position is one element in {p0, p1, p2, K, pkmax-1}, 0 ≤ k < kmax, 0 ≤ pk < NCB, pk is an integer, k is an integer, NCB is a length of the buffer sequence W, kmax is an integer greater than or equal to 4, and there are two or more differences between two adjacent values in {p0, p1, p2, K, pkmax-1,}. A bit sequence for initial transmission or retransmission is properly determined, so that decoding performance of a communications device on a receive end after receiving the bit sequence is improved, a decoding success rate is enhanced, and a quantity of retransmission times is further reduced.