Flexible Optical Modem Excess Capacity Management

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Solution Overview

Problem

Fiber optic communication networks face challenges in utilizing excess optical capacity and margin due to fixed modulation schemes, leading to inefficient data throughput and increased operational complexity, especially as they approach the Shannon Limit and require hitless modulation changes to maintain service integrity.

Innovation Solution

Implementing flexible optical modems that support variable bit-rates and adaptive modulation formats, integrated with a management and control plane to manage excess capacity, allowing for hitless modulation scheme changes and spectral shaping to optimize spectral efficiency without impacting existing traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fixed modulation schemes are used in optical networks, then system stability is maintained, but excess optical capacity and margin cannot be utilized, leading to inefficient data throughput

Engineering Contradiction:
Improvedata throughputVSAvoidmodulation scheme flexibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic modulation schemes that can adaptively change based on available optical margin and channel conditions. The system transitions from fixed modulation formats to variable modulation formats (e.g., QPSK, 16-QAM, 64-QAM) that can be adjusted in real-time to utilize excess capacity while maintaining system stability through controlled transition mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes modulation parameters (order, format, rate) based on detected optical margin conditions. When excess margin is available, the system increases modulation order to boost throughput; when margin is consumed, it reduces modulation order to maintain reliability, thereby optimizing productivity across different operational states.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If adaptive modulation techniques are implemented to utilize excess margin, then spectral efficiency is improved, but system complexity increases due to margin detection and dynamic reconfiguration requirements

Engineering Contradiction:
Improvespectral efficiencyVSAvoidmodulation management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements self-service mechanisms where the system automatically detects optical margin, determines appropriate modulation schemes, and executes transitions without external intervention. The transponder autonomously monitors channel conditions and adjusts modulation parameters, reducing the need for complex external management while improving spectral efficiency.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system employs feedback mechanisms where margin detection results inform modulation scheme selections. The transponder continuously monitors optical conditions, feeds this information back to the modulation controller, and adjusts parameters accordingly, creating a closed-loop system that optimizes spectral efficiency while managing complexity through automated decision-making.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If modulation scheme changes are performed in traditional optical networks, then capacity can be adjusted, but service interruption occurs causing operational complexity and potential data loss

Engineering Contradiction:
Improvecapacity adjustment capabilityVSAvoidservice continuity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements preliminary actions by detecting margin conditions and preparing modulation transitions in advance. The system evaluates whether excess margin exists before initiating changes, and if conditions are favorable, it proceeds with hitless transitions. This preliminary assessment ensures that capacity adjustments can be made without service interruption, maintaining reliability while enabling adaptability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses available optical margin as a cushion to absorb the effects of modulation scheme changes. When sufficient excess margin is detected, the system can transition to higher-order modulation formats without risking service quality. This beforehand cushioning allows capacity adjustments to be made safely without causing service interruption or data loss.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Productivity

If excess margin is utilized by increasing data throughput, then operational costs are reduced, but the system approaches the Shannon Limit reducing future expansion capability

Engineering Contradiction:
Improvedata throughputVSAvoidsignal quality margin
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic capacity management where the system continuously monitors optical margin and adjusts throughput accordingly. When excess margin is available, the system increases throughput to reduce operational costs; when margin levels indicate approaching the Shannon Limit, the system reduces throughput to preserve signal quality. This dynamic adjustment resolves the contradiction by allowing both high productivity and maintained reliability at different times.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (data rate, modulation format) based on real-time margin conditions. By adjusting these parameters dynamically, the system can operate at high throughput when margin permits, reducing costs, and transition to conservative operation when approaching capacity limits, thereby maintaining both productivity and reliability across different operational phases.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3105887B1Methods, apparatus and system for managing excess optical capacity and margin in optical networks
Publication Date: 2022.03.30 CIENA CORP
  • EP3105887B1 patent drawingFigure 1~2
  • EP3105887B1 patent drawingFigure 3
  • EP3105887B1 patent drawingFigure 4

AI summary

Systems and methods for managing excess optical capacity and margin in optical networks include determining excess margin relative to margin needed to insure performance at a nominal guaranteed rate in a flexible optical modem configured to communicate over an optical link; causing the flexible optical modem to consume most or all of the excess margin, wherein capacity increased above the nominal guaranteed rate in the flexible optical modem is excess capacity; and mapping the excess capacity to one or more logical interfaces for use by a management system, management plane, and/or control plane.