Spatially Coupled QC-LDPC Code Generation With Simulated Annealing
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Solution Overview
Problem
Existing methods for generating LDPC codes face challenges in computational complexity and ease of implementation, particularly for high data rate applications like 5G wireless communication systems, where current approaches such as randomly constructed irregular LDPC codes are inefficient due to randomness and complexity in analysis and hardware implementation.
Innovation Solution
The development of an apparatus and method for generating spatially-coupled low-density parity-check (LDPC) codes using a set of base matrix parameters, where a processor discards protographs and codes based on simulated annealing techniques, minimum Hamming distance, balanced girth, and extrinsic message degree thresholds to optimize parity check matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If randomly constructed irregular LDPC codes are used, then asymptotic performance approaches Shannon limit, but randomness hinders ease of analysis and implementation
Solution Approach 1:
The code construction is segmented into two distinct parts: a random protograph stage that ensures good asymptotic performance, and a structured QC-LDPC lifting stage that provides ease of analysis and implementation. This segmentation allows each part to optimize for its specific strength while avoiding the weaknesses of the other approach.
Solution Approach 2:
The protograph serves as an intermediary between the random construction approach and the structured QC-LDPC approach. The random protograph defines the code structure, which is then lifted to create a deterministic QC-LDPC code, thus mediating between randomness and structure.
2Productivity
If QC-LDPC codes are used for high data rates, then encoding efficiency improves, but code length and rate adaptation complexity increases
Solution Approach 1:
The code construction method is made dynamic by allowing adjustment of the lifting size parameter, which enables code length and rate adaptation. This dynamic parameter allows the same base protograph to generate codes of different lengths and rates, simplifying adaptation complexity while maintaining encoding efficiency.
Solution Approach 2:
By changing the lifting size parameter, the system can adapt code length and rate without changing the fundamental code structure. This parameter change approach maintains encoding efficiency while providing flexible adaptation to different communication requirements.
3Reliability
If spatially-coupled LDPC codes are used, then performance under moderate to high lengths improves, but structure complexity for analysis and design increases
Solution Approach 1:
The spatially-coupled code is segmented from a standard QC-LDPC code by introducing coupling matrices that connect different code blocks. This segmentation allows the code to achieve better performance under moderate to high lengths while maintaining a structured form that is more manageable than fully random codes.
Data Source
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AI summary
The invention relates to an apparatus (100) for providing at least one parity check matrix defining a spatially-coupled low density parity check, LDPC, code on the basis of a set of base matrix parameters defining a plurality of base matrices, each base matrix of the plurality of base matrices being associated with a protograph of a plurality of protographs, wherein the set of base matrix parameters defines the size WxC, a circulant size N, a maximal column weight M and a set of allowed column weights of the plurality of base matrices, wherein the apparatus (100) comprises: a processor (101) configured to: generate on the basis of the plurality of protographs a set of candidate protographs by discarding protographs of the plurality of protographs; lift the protographs of the set of candidate protographs for generating a plurality of codes; and generate on the basis of a plurality of codes a set of candidate codes by discarding codes of the plurality of codes, wherein the processor (101) is configured to lift the protographs of the set of candidate protographs on the basis of a simulated annealing technique.