Subchannel Encoding Device Grouping for Circuit Scale Reduction

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Solution Overview

Problem

As the number of subchannels increases in optical communication systems, the number of probability distribution shaping-encoding units required also increases, leading to a significant circuit scale problem that hinders the efficient enhancement of information rate.

Innovation Solution

The system divides subchannels into groups and uses a single probability distribution shaping-encoding unit to determine the entropy for each group based on average or median SNR values, allowing for increased information rate without the need for as many units as the total number of subchannels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a probability distribution shaping-encoding unit is provided in each subchannel, then the information rate in the total of a plurality of subchannels can be increased, but the circuit scale increases

Engineering Contradiction:
Improveinformation rateVSAvoidcircuit scale
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple probability distribution shaping-encoding units into a single shared unit. This single unit services multiple subchannels by determining entropy based on average or median SNR values across the subchannels, thereby reducing the total number of encoding units from M×N (where M is the number of subchannels and N is the number of groups) to just one, while still maintaining the ability to increase information rate through probabilistic shaping.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single probability distribution shaping-encoding unit is designed to be universal, serving multiple subchannels with different SNR characteristics. By using average or median SNR values as a common basis for entropy determination across different subchannel groups, the unit achieves multi-functionality without requiring separate dedicated units for each subchannel, thus reducing circuit complexity while maintaining adaptability.

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

2Productivity

If the number of subchannels increases, then the throughput increases, but the number of probability distribution shaping-encoding units increases

Engineering Contradiction:
ImprovethroughputVSAvoidnumber of units
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the functionality of multiple subchannel-specific encoding units into a single shared unit that can serve all subchannels. This merging approach allows the system to handle an increasing number of subchannels for higher throughput without proportionally increasing the number of encoding units, thus breaking the direct correlation between subchannel count and unit count.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the parameter basis for entropy determination from individual subchannel SNR values to aggregate metrics (average or median SNR across multiple subchannels). This parameter change enables a single encoding unit to adapt to multiple subchannels with varying SNR characteristics, allowing throughput to scale with subchannel count while keeping the number of units constant.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3989502B1Subchannel encoding device, subchannel decoding device, subchannel encoding method, subchannel decoding method, and subchannel multiplexing optical communication system
Publication Date: 2023.12.27 MITSUBISHI ELECTRIC CORP
  • EP3989502B1 patent drawingFigure 1
  • EP3989502B1 patent drawingFigure 2
  • EP3989502B1 patent drawingFigure 3

AI summary

A subchannel encoding device (11) is configured to include: a probability distribution shaping-encoding unit (21) for dividing M × N (M is an integer of two or more, and N is an integer of one or more) subchannels into N groups, shaping a probability distribution of transmission modulation symbols of each group on the basis of signal-to-noise ratios of the M × N subchannels, and converting an information bit string into a shaped bit string corresponding to the probability distribution of the transmission modulation symbols of each group; a subchannel signal generating unit (22) for generating each subchannel signal in the M × N subchannels from the shaped bit string; and a signal multiplexing unit (26) for multiplexing the M × N subchannel signals generated by the subchannel signal generating unit (22) to generate a subchannel multiplexed signal.