Polar Code Interleaver Layout for Lower BLER in QAM
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Solution Overview
Problem
Existing wireless communication systems using polar codes face challenges in achieving sufficient performance in terms of Signal-to-Noise Ratio (SNR) and Block Error Rate (BLER), especially under Additive White Gaussian Noise (AWGN), due to inadequate interleaver designs for higher-order modulation schemes like 16-QAM or 64-QAM.
Innovation Solution
A new interleaver design for polar codes utilizing a right isosceles triangle-shaped or trapezoid-shaped matrix with varying column counts between rows, where coded bits are fed into successive rows from top to bottom and read out from left to right, accompanied by the removal of inter-column permutation to reduce complexity and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rectangular interleavers are used for polar codes, then the structure is simple and easy to implement, but the performance in terms of SNR and BLER is insufficient, especially for higher-order modulation schemes
Solution Approach 1:
The patent applies asymmetry by transforming the traditional rectangular interleaver into a triangular interleaver structure where the number of columns varies between rows. Specifically, the first row has N columns while subsequent rows have progressively fewer columns, creating an asymmetric distribution pattern that improves error randomization performance for polar codes while maintaining implementation feasibility.
Solution Approach 2:
The patent changes the structural parameters of the interleaver from a fixed rectangular grid to a variable triangular grid. The key parameter change is in the column count per row, which follows a specific pattern (N, N-1, N-2, ..., 1) rather than being uniform across all rows. This parameter variation enables better performance for higher-order modulations like 16-QAM and 64-QAM.
2Reliability
If complex interleaver designs are used to improve performance, then SNR and BLER performance improves, but computational complexity and latency increase
Solution Approach 1:
The patent segments the code block into a triangular matrix structure where each row has a different number of columns. This segmentation approach distributes the coded bits across varying row lengths, creating effective interleaving without requiring complex permutation operations. The segmented triangular structure achieves performance comparable to random interleavers while maintaining simpler computational requirements.
3Reliability
If inter-column permutation is included to enhance interleaving, then error randomization improves, but processing latency and complexity increase
Solution Approach 1:
The patent extracts and removes the inter-column permutation operation from the traditional interleaving process. By relying solely on the triangular row-filling structure without additional permutation steps, the design achieves effective error randomization while reducing processing latency and computational overhead. This extraction of unnecessary operations optimizes the interleaver for real-time communication applications.
Data Source
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AI summary
Aspects of the disclosure relate to wireless communication devices configured to encode information blocks to produce code blocks and interleave the code blocks utilizing an interleaver including a plurality of rows and a plurality of columns, where the number of columns of the interleaver varies between the rows. In some examples, the interleaver includes a right isosceles triangle-shaped matrix of rows and columns. In other examples, the interleaver includes a trapezoid-shaped matrix of rows and columns.