Turbo Code Interleaver Layout Matched to Puncturing Patterns

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Solution Overview

Problem

Current turbo codes face challenges in optimizing the interleaving process for improved coding efficiency, particularly at low error rates, due to cumbersome parameter calculation methods and suboptimal performance across various coding efficiencies, leading to inefficiencies in error correction and increased computational complexity.

Innovation Solution

A method for turbo encoding that incorporates a specific interleaving function based on a periodic punching pattern, distributing information symbols into layers while respecting an interleaving function defined by the punching pattern, which adjusts the interleaving parameters to enhance coding and decoding performance by reducing the search space for interleaving parameters and preserving the structure of punching patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional interleaving methods are used, then the turbo code structure is simple, but the coding performance at low error rates is suboptimal

Engineering Contradiction:
Improvecoding performance at low error ratesVSAvoidinterleaving parameter calculation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the interleaving parameters (period P, degree of disorder Q, adjustment values Tl and Al) based on the punching pattern to optimize coding performance. By adapting these parameters to the specific punching pattern being used, the system achieves better performance at low error rates without requiring completely new interleaving structures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary calculation of interleaving parameters based on the punching pattern before encoding. By pre-determining the optimal parameters (P, Q, Tl, Al) according to the punching pattern, the system avoids complex real-time calculations during encoding while maintaining optimized performance.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the same encoder and decoder are used for all coding efficiencies, then device complexity is reduced, but coding efficiency optimization is limited

Engineering Contradiction:
Improvecoding efficiency adaptationVSAvoidinterleaver design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal interleaver design that works across different coding efficiencies by parameterizing the interleaving function. The same interleaver structure can be used for various coding rates (1/3, 2/3, 3/4, etc.) by simply adjusting the parameters (P, Q, Tl, Al) according to the punching pattern, eliminating the need for multiple specialized encoders and decoders.

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

3Productivity

If information symbols are punched to increase coding efficiency, then coding rate is improved, but minimum Hamming distance decreases

Engineering Contradiction:
Improvecoding efficiencyVSAvoidminimum Hamming distance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent adjusts the interleaving parameters specifically to compensate for the effects of punching. By modifying the period P, degree of disorder Q, and adjustment values Tl and Al based on the punching pattern, the system maintains adequate minimum Hamming distance while achieving the desired coding efficiency through selective punching of information and redundancy symbols.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3311495B1Interleaver design for turbo codes in dependence on the puncturing pattern
Publication Date: 2021.02.24 ORANGE SA
  • EP3311495B1 patent drawingFigure 1A~2
  • EP3311495B1 patent drawingFigure 3~4
  • EP3311495B1 patent drawingFigure 5

AI summary

The present invention relates to a method for coding a digital input message, having K information symbols, using a turbo encoder forming a turbo code, the turbo encoder comprising an interleaver and first and second encoders (C1, C2) encoding according to at least one elementary code, and delivering information symbols and redundancy symbols. According to the invention, a puncturing of symbols delivered by the turbo encoder being carried out according to at least one periodic puncturing pattern of length N, defining the puncturing period N, said interleaver distributes the information symbols of said input message in Q input message layers interleaved according to an interleaving function defined from said at least one puncturing pattern, according to the relationship π(i) = Pi + S(i mod Q) mod K = Pi + (Tl + Al Q) mod K.