Permuted Belief Propagation Decoding for Short Algebraic Codes

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Solution Overview

Problem

Current decoding techniques for short packet length communications, particularly in the range of 30-300 bits, face challenges with increased computational complexity, leading to high latency and power consumption due to the complexity of decoding linear algebraic codes, which is impractical for applications like command and control systems where reliability is critical.

Innovation Solution

The implementation of a permuted belief propagation decoding method that iteratively exchanges messages between variable and check nodes in a factor graph, applying permutations to map codewords onto different valid codewords, reducing the need for heuristic damping factors and multiple decoders, thus simplifying the decoding process and reducing computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional decoding techniques are used for short algebraic codes, then error correction capability is achieved, but computational complexity increases leading to high latency and power consumption

Engineering Contradiction:
Improveerror correction capabilityVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The decoding process is segmented into iterative message passing between variable nodes and check nodes in a factor graph, breaking down the complex decoding task into smaller, manageable iterations that reduce overall computational burden while maintaining error correction capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies dynamic permutations to the code space during decoding iterations, adapting the decoding approach based on the current state of message passing. This dynamic transformation of codewords through permutations allows the system to explore different decoding paths efficiently, reducing computational complexity while preserving reliability

Inventive Principle:
Principle #15Dynamics

2Reliability

If conventional decoding techniques are used for short algebraic codes, then error correction is performed, but latency increases due to multiple iterations and heuristic damping factors

Engineering Contradiction:
Improveerror correctionVSAvoiddecoding latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent prepares permutation operators in advance that can be applied to codewords during the decoding process. These pre-prepared transformations allow the decoder to quickly explore different codeword configurations without requiring complex heuristic damping factors, thereby reducing the number of iterations needed and lowering latency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter space by applying permutations to transform codewords into different valid codewords within the code space. This parameter transformation approach replaces the need for heuristic damping factors and multiple decoders, reducing iterative complexity and decoding latency while maintaining error correction performance

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple decoders and heuristic damping factors are used, then decoding accuracy is improved, but device complexity and power consumption increase

Engineering Contradiction:
Improvedecoding accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements a universal decoding approach where a single decoder can handle multiple decoding scenarios by applying different permutations to the code space. This eliminates the need for multiple specialized decoders and heuristic damping factors, reducing power consumption while maintaining decoding accuracy through the flexible application of permutation-based transformations

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

Data Source

PatentUS9960790B2Belief propagation decoding for short algebraic codes with permutations within the code space
Publication Date: 2018.05.01 KK TOSHIBA
  • US9960790B2 patent drawing
  • US9960790B2 patent drawing
  • US9960790B2 patent drawing

AI summary

A method of processing data received over a channel includes receiving data representing probabilities associated with a plurality of variables and receiving a parity check matrix associated with a factor graph which includes variable nodes and check nodes connected by edges. After each exchange of messages between the variable nodes and check nodes, messages are calculated based on messages received at the variable nodes and permuted messages to be sent from the variable nodes in the next iteration are calculated by applying a permutation to the calculated messages. The permutation is of a set of permutations which map each codeword of the set of codewords onto a different codeword of the set of codewords. Soft values associated to variable nodes can be accumulated over two iterations of the message exchange processing.