Spatially Coupled Polar Codes for Flexible Block Lengths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polar codes face inflexibility in block length selection, as each code block must be a power of 2, leading to performance degradation due to heavy puncturing when supporting various block lengths, and existing methods to improve granularity, such as using small block lengths, limit the minimum distance of the code.
Innovation Solution
Spatially coupling multiple constituent polar codes with different block lengths to form a spatially coupled polar code, where the block length of the overall code is the sum of individual block lengths, allowing for flexible block length selection without performance degradation, and using feedforward decoding to enhance the minimum distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polar codes use fixed block lengths that are powers of 2, then the coding structure is simple and decoding is efficient, but the adaptability to different block length requirements is poor
Solution Approach 1:
The polar code is divided into multiple constituent polar codes with different block lengths. Each constituent code can be independently configured, allowing the overall code to achieve flexible block length adaptation while maintaining the simplicity of individual power-of-2 based constituent codes.
Solution Approach 2:
The patent combines multiple polar codes with different block lengths into a composite spatially coupled polar code structure. This composite structure leverages the strengths of individual power-of-2 based codes while achieving overall flexibility in block length selection.
2Adaptability or versatility
If polar codes support various block lengths through puncturing, then the adaptability improves, but the performance degrades due to heavy puncturing
Solution Approach 1:
Instead of puncturing a single long code, the system segments the code into multiple shorter constituent codes with different lengths. This eliminates the need for heavy puncturing while achieving flexible block length support, as each constituent code can be naturally configured to its optimal length.
Solution Approach 2:
The patent changes the block length parameter of each constituent polar code to match the desired overall block length exactly, avoiding the need for puncturing operations that would degrade performance. The spatial coupling structure maintains reliability while adapting to different length requirements.
3Adaptability or versatility
If small block length codes are used to achieve finer granularity, then the block length flexibility improves, but the minimum distance of the code is limited
Solution Approach 1:
The patent merges multiple small block length polar codes into a spatially coupled structure. The spatial coupling combines the strengths of individual small codes while achieving a larger effective minimum distance through the coupled structure, thus improving both granularity and code strength simultaneously.
Solution Approach 2:
By creating a composite spatially coupled polar code from multiple constituent codes, the system achieves a minimum distance that exceeds what any individual small block length code could provide alone, while maintaining fine block length granularity through the modular constituent structure.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method in a node (110, 115) comprises generating (604) a plurality of constituent polar codes, each of the plurality of constituent polar codes having an associated block length and an associated set of information bits. The method comprises coupling (608) at least a portion of the sets of information bits associated with each of the plurality of constituent polar codes to generate a spatially coupled polar code. The method comprises encoding (612) a wireless transmission using the spatially coupled polar code.