LDPC Matrix Structure for Lower-SNR WiFi Decoding

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Solution Overview

Problem

Current communication systems face challenges in achieving optimal signal-to-noise ratio (SNR) and bit error rate (BER) due to interference and noise, particularly in dense deployments where many devices operate in close proximity, such as in WiFi or wireless local area networks, limiting their performance and throughput.

Innovation Solution

The implementation of novel architectures and methods utilizing Low Density Parity Check (LDPC) codes, which enable improved spatial re-use and error correction in communication devices, allowing for enhanced performance in dense deployments by encoding and decoding signals using LDPC matrices with specific sub-matrix structures and puncturing patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional error correction coding is used in dense wireless deployments, then communication reliability is maintained, but signal-to-noise ratio performance degrades and throughput is limited

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidthroughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies parameter changes by modifying the LDPC code structure through puncturing patterns and sub-matrix configurations. Specifically, the parity check matrix is constructed with specific sub-matrices (e.g., identity matrices, zero matrices) in predetermined positions, and puncturing is applied to select subsets of coded bits for transmission. This changes the effective code rate and structure to optimize performance in dense deployments, achieving both improved reliability and throughput by adapting the coding parameters to the channel conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If forward error correction coding is applied to correct transmission errors, then bit error rate improves, but signal-to-noise ratio requirement increases

Engineering Contradiction:
Improvebit error rateVSAvoidsignal-to-noise ratio
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the coding parameters by using LDPC codes with specific puncturing patterns and sub-matrix structures. The parity check matrix is designed with specific configurations (e.g., identity matrices at certain positions, zero matrices elsewhere) that allow flexible control of the code rate and error correction capability. By adjusting these parameters, the system achieves better bit error rate performance while reducing the required signal-to-noise ratio compared to conventional coding schemes.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If LDPC codes with specific sub-matrix structures are used, then spatial re-use and error correction improve, but device complexity increases

Engineering Contradiction:
Improvespatial re-useVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the parity check matrix into multiple sub-matrices (e.g., identity matrices, zero matrices, and other structured matrices) arranged in a specific block structure. This segmentation allows the encoder and decoder to process data in manageable blocks, improving spatial re-use efficiency. The structured sub-matrices enable efficient implementation of encoding and decoding operations, reducing the computational complexity compared to using a completely dense parity check matrix.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes structural parameters by defining specific configurations for sub-matrices within the parity check matrix. The positions, sizes, and types of sub-matrices are predetermined and optimized for performance. This structured approach allows devices to implement the coding scheme with reduced complexity by leveraging the regular patterns in the sub-matrix arrangements, rather than handling arbitrary dense matrices.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10313054B2Low density parity check (LDPC) codes for communication devices and systems
Publication Date: 2019.06.04 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • US10313054B2 patent drawing
  • US10313054B2 patent drawing
  • US10313054B2 patent drawing

AI summary

A communication device (alternatively, device) includes a processor configured to support communications with other communication device(s) and to generate and process signals for such communications. In some examples, the device includes a communication interface and a processor, among other possible circuitries, components, elements, etc. to support communications with other communication device(s) and to generate and process signals for such communications. In some examples, a device encodes information using a low density parity check (LDPC) code to generate an LDPC coded signal and transmits the LDPC coded signal to another communication device. in other examples, a device receives an LDPC coded signal from another communication device and decodes the LDPC coded signal using an LDPC matrix. The LDPC matrix includes a left hand side matrix and a right hand side matrix (e.g., having CSI (Cyclic Shifted Identity) sub-matrices on a main diagonal and another diagonal adjacently located to the main diagonal).