LDPC Signal Decoder Quantization Switching for Variable Bit Depth

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Solution Overview

Problem

Current communication systems using LDPC codes are limited in their ability to adapt decoding performance based on the number of quantization bits, as they are optimized for either uniform or non-uniform quantization schemes without the flexibility to switch between them, leading to suboptimal decoding outcomes depending on the number of quantization bits.

Innovation Solution

A signal reception apparatus and method that incorporates both uniform and non-uniform quantizers, along with optimized check and variable node processors, allowing the decoder to switch between quantization schemes based on the number of quantization bits, thereby optimizing decoding performance across varying bit conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed quantization scheme (either uniform or non-uniform) is used in the decoder, then the decoder complexity is reduced and implementation is simplified, but the decoding performance becomes suboptimal when the number of quantization bits varies

Engineering Contradiction:
Improvedecoder complexityVSAvoiddecoding performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The decoder dynamically selects between uniform and non-uniform quantization schemes based on the number of quantization bits. When quantization bits are 5 or more, uniform quantization is used; when quantization bits are 4 or fewer, non-uniform quantization is used. This dynamic adaptation optimizes decoding performance for different bit conditions without significantly increasing overall decoder complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the quantization parameter (scheme type) based on the quantization bit depth. By switching between uniform and non-uniform quantization schemes according to the number of bits, the system adapts to different precision requirements, improving reliability across varying operational conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the decoder is optimized for a specific quantization scheme, then decoding performance is improved for that scheme, but the system loses adaptability to different quantization bit conditions

Engineering Contradiction:
Improvedecoding performanceVSAvoidquantization scheme flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The decoder is designed to support both uniform and non-uniform quantization schemes within a single implementation. By incorporating functionality for both schemes and selecting based on bit depth, the decoder becomes universal and can handle various quantization conditions optimally, rather than being specialized for just one scheme.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system adapts the quantization parameter (scheme selection) based on the input signal's quantization bit depth, enabling the decoder to maintain high performance across different operational scenarios.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If uniform quantization is used with 5 or more quantization bits, then quantization precision is maintained, but non-uniform quantization cannot be applied to improve performance in low-bit conditions

Engineering Contradiction:
Improvequantization precisionVSAvoiddecoding performance in low-bit conditions
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

Different quantization schemes are applied locally based on the specific bit condition: uniform quantization is used when bits ≥ 5 to maintain precision, while non-uniform quantization is used when bits ≤ 4 to optimize performance in low-bit conditions. This localized adaptation ensures optimal performance for each operational regime.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The quantization parameter changes based on bit depth thresholds, allowing the system to switch between uniform and non-uniform schemes to maintain both precision and performance across different quantization conditions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS7450033B2Apparatus and method for receiving signal in a communication system
Publication Date: 2008.11.11 SAMSUNG ELECTRONICS CO LTD
  • US7450033B2 patent drawing
  • US7450033B2 patent drawing
  • US7450033B2 patent drawing

AI summary

An apparatus and method for receiving a signal in a signal reception apparatus of a communication system is provided. The signal reception method includes receiving a signal, and decoding the received signal using a Low Density Parity Check (LDPC) decoding scheme according to the number of quantization bits.