Contrast Coding for Multi-Level FEC BER Matching

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Solution Overview

Problem

Existing communication systems face challenges in managing bit error rates (BER) across different bits due to varying channel qualities, leading to inefficiencies in error correction and increased overhead in Forward Error Correction (FEC) schemes, which can result in higher costs, larger system sizes, and increased heat generation.

Innovation Solution

The implementation of contrast coding, which adjusts bit error rates (BER) through contrast encoding at the transmitter and contrast decoding at the receiver, allowing for better matching of FEC schemes and modulation formats, thereby achieving higher noise tolerance, greater data capacity, or smaller system sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stronger FEC schemes are used to provide better error protection, then reliability is improved, but information rate decreases and device complexity increases

Engineering Contradiction:
Improveerror protectionVSAvoidinformation rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the information bits into multiple subsets, each protected by a different FEC scheme with appropriate strength. This allows different parts of the data to receive differentiated protection levels, avoiding the need to apply strong FEC to all bits and thereby maintaining higher overall information rate while ensuring critical bits are well-protected.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different FEC schemes (with different strengths and overheads) to different subsets of bits based on their importance and channel conditions. This local differentiation optimizes the balance between reliability and information rate by concentrating strong protection only where necessary rather than uniformly across all data.

Inventive Principle:
Principle #3Local quality

2Reliability

If stronger FEC schemes are used to provide better error protection, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveerror protectionVSAvoidcircuitry size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By segmenting bits into subsets with different protection requirements, the patent avoids implementing a single complex strong FEC scheme for all bits. Instead, multiple simpler FEC schemes can be applied to different subsets, reducing overall device complexity while maintaining equivalent or better reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies FEC schemes locally to different bit subsets based on their specific needs, allowing the use of simpler coding schemes for less critical bits and reserving complex schemes only for critical bits, thereby optimizing the complexity-reliability tradeoff.

Inventive Principle:
Principle #3Local quality

3Reliability

If stronger FEC schemes are used to provide better error protection, then reliability is improved, but heat generation increases

Engineering Contradiction:
Improveerror protectionVSAvoidheat generation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent segments the data stream and applies FEC processing only to the necessary subsets, reducing the total computational load and heat generation compared to applying strong FEC to all bits. This selective approach maintains reliability for critical bits while minimizing overall energy consumption and heat.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By applying different FEC strengths locally to different bit subsets, the patent minimizes the use of computationally intensive strong FEC schemes to only where necessary, thereby reducing overall heat generation while maintaining adequate error protection for all transmitted data.

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If contrast coding is applied to adjust BERs of different bit classes, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvematching of FEC schemes to bit classesVSAvoidencoding and decoding complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments bits into classes based on their BER characteristics and applies appropriate FEC schemes to each class. This segmentation enables adaptability to different channel conditions while managing complexity by processing each segment independently with tailored coding rather than requiring complex universal processing.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3665782B1Forward error correction with outer multi-level code and inner contrast code
Publication Date: 2024.03.20 CIENA CORP
  • EP3665782B1 patent drawingFigure 1
  • EP3665782B1 patent drawingFigure 2~3
  • EP3665782B1 patent drawingFigure 4

AI summary

In data communications, a suitably designed contrast coding scheme, comprising a process of contrast encoding (108) at a transmitter end (101) and a process of contrast decoding (120) at a receiver end (103), may be used to create contrast between the bit error rates 'BERs' experienced by different classes of bits. Contrast coding may be used to tune the BERs experienced by different subsets of bits, relative to each other, to better match a plurality of forward error correction 'FEC' schemes (104, 124) used for transmission of information bits (102), which may ultimately provide a communications system (100) having a higher noise tolerance, or greater data capacity, or smaller size, or lower heat.