Reed-Muller Code Interleaving for Noncoherent Fading Decoding

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Solution Overview

Problem

Conventional Reed-Muller codes are ineffective in noncoherent fading channels due to phase ambiguity, and decoding algorithms are sensitive to phase changes, leading to difficulties in decoding coded bits that are far apart.

Innovation Solution

An interleaver design for noncoherent Reed-Muller codes that permutes coded bits into the same frequency hop or close locations, allowing for effective decoding by a receiver.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional Reed-Muller codes are used in noncoherent fading channels, then the system can operate without coherent detection, but decoding fails due to phase ambiguity and sensitivity to phase changes

Engineering Contradiction:

Improvenoncoherent channel operationVSAvoiddecoding reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The codeword is segmented into multiple groups where each group contains coded bits that are close to each other in the transmitted sequence. This segmentation ensures that bits within each group experience similar channel phase conditions, enabling reliable noncoherent decoding by processing each group independently with respect to phase ambiguity.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If coded bits are placed far apart in the transmission sequence, then frequency diversity is improved, but decoding becomes difficult due to phase changes between frequency hops

Engineering Contradiction:

Improvefrequency diversityVSAvoiddecoding difficulty

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The interleaver creates local groups of coded bits that are transmitted close together in time and frequency, giving each group uniform local characteristics. This allows the receiver to decode each group using local phase information without being affected by phase changes in other parts of the transmission, thus maintaining decoding feasibility while still providing frequency diversity across different groups.

Inventive Principle:

Principle #3Local quality

3Reliability

If an interleaver permutes coded bits into close locations, then decoding reliability improves in noncoherent channels, but the complexity of the transmission system increases

Engineering Contradiction:

Improvedecoding reliabilityVSAvoidinterleaver complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The interleaver is designed with a predetermined structure that groups coded bits into specific patterns before transmission. This preliminary organization of bits into decodeable groups simplifies the receiver's task by ensuring that bits requiring joint decoding are already positioned close together, reducing the computational complexity of noncoherent decoding algorithms.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The interleaver parameters (such as group size, permutation pattern, and spacing) are optimized to balance decoding reliability with implementation complexity. By adjusting these parameters, the system achieves sufficient grouping of coded bits for reliable noncoherent decoding while avoiding excessive complexity in both the transmitter interleaver and receiver deinterleaver implementations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12580680B2Interleaver design for noncoherent reed muller codes

Publication Date: 2026.03.17 QUALCOMM INC

AI summary

A configuration for a device to interleave a codeword, where the codeword is based on an enhanced noncoherent error correction code. The apparatus encodes a set of bits based on a noncoherent error correction code to generate a first codeword. The apparatus interleaves the first codeword to permute coded bits of the first codeword into a second codeword. The apparatus transmits the second codeword to a second device.