Wi-Fi LDPC Codeword Extension Through Re-Lifting Matrices
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Solution Overview
Problem
Existing LDPC codes for Wi-Fi face challenges in efficiently extending codeword lengths without significant hardware burden, as device encoders and decoders struggle with power, area, latency, and cost constraints, particularly with increasing bandwidth and modulation orders.
Innovation Solution
The technique involves performing additional liftings on existing LDPC codes to extend codeword lengths, preserving the structure of original codes to minimize hardware impact, allowing for seamless integration and reduced decoding complexity, and enabling backward compatibility by generating extended LDPC matrices and codes through cyclic, product, or swapping liftings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LDPC codes are extended to longer codeword lengths to support higher bandwidth and modulation orders, then communication performance is improved, but hardware complexity and resource requirements increase significantly
Solution Approach 1:
The patent applies segmentation by dividing the extended LDPC code into multiple segments or blocks. The encoding process processes input bits in segments, generating corresponding codeword segments that can be handled by existing hardware structures. This allows long codewords to be processed in manageable chunks without requiring complete redesign of hardware for entire extended codes.
Solution Approach 2:
The patent implements nesting by embedding the original LDPC code structure within the extended code framework. The base matrix and its derived structures are nested within extended matrices through systematic lifting operations. This nested structure enables existing hardware designed for original codes to operate within the extended code context with minimal modifications.
2Reliability
If LDPC codes are extended to longer lengths, then error correction capability is improved, but decoding latency increases
Solution Approach 1:
The patent segments the decoding process to match the segmented encoding structure. Decoders can process individual segments or blocks independently or in parallel, reducing overall decoding latency compared to processing entire extended codes sequentially. This segmentation maintains error correction capability while enabling faster processing through parallelization.
Solution Approach 2:
The patent employs preliminary action through pre-computation of lifting matrices and permutation patterns during system initialization. These pre-computed structures are stored and reused during actual encoding and decoding operations, eliminating the need for real-time complex calculations and thereby reducing decoding latency while maintaining extended code error correction capabilities.
3Adaptability or versatility
If additional lifting operations are performed to extend LDPC codes, then code flexibility and adaptability are improved, but encoding and decoding complexity increase
Solution Approach 1:
The patent achieves universality by designing extended LDPC codes that maintain compatibility with existing decoding algorithms and hardware structures. The systematic lifting approach ensures that extended codes share fundamental structural properties with original codes, allowing single hardware designs to handle both original and extended codes through configuration changes rather than complete redesigns.
Solution Approach 2:
The patent applies parameter changes by modifying code parameters such as lifting size, block length, and matrix dimensions while preserving the underlying code structure and decoding methodology. This allows flexible adaptation to different communication requirements (bandwidth, modulation orders) by adjusting parameters rather than changing the fundamental encoding/decoding algorithms, thereby controlling complexity.
Data Source
AI summary
This disclosure provides methods, components, devices and systems for low-density parity check (LDPC) coding. Some aspects more specifically relate to extending LDPC codewords to produce longer codewords. In some examples, a first wireless device may generate a baseline LDPC code by performing a first lifting on a base matrix, which may produce an LDPC code used for a current Wi-Fi implementation. The first wireless device may then perform a second lifting or a re-lifting (such as a cyclic lifting, a product lifting, a swapping lifting, or a combination thereof) to generate an extended lifted code. This extended lifted code may be an extension of the first LDPC code such that the first LDPC code may be preserved as part of the extended code. Then first wireless device may then transmit the extended LDPC code as an extended or lifted codeword.