Adaptive Optical Network Reach Extension via Subcarrier Multiplexing
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Solution Overview
Problem
The transmission reach of optical channels in optical networks is limited by higher order modulation formats and nonlinear effects, which restricts the capacity and efficiency of data transmission.
Innovation Solution
An adaptive optical network system that selects the modulation format and number of subcarriers based on target distance and fiber characteristics, using a network management system to configure transponders for optimal spectral efficiency and reach extension through subcarrier multiplexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher order modulation formats are used to increase data rate, then spectral efficiency is improved, but transmission reach deteriorates
Solution Approach 1:
The patent segments the optical channel into multiple subcarriers (e.g., 4 subcarriers at 8 Gbaud each, or 8 subcarriers at 4 Gbaud each) to reduce the symbol rate per subcarrier. This segmentation allows the system to achieve extended transmission reach while maintaining high spectral efficiency through parallel data transmission across multiple subcarriers.
Solution Approach 2:
The patent implements dynamic adaptation of modulation formats and subcarrier configurations based on channel conditions. The system can switch between different modulation formats (QPSK, 8-QAM, 16-QAM) and adjust the number of subcarriers to optimize both spectral efficiency and transmission reach for different network scenarios.
2Length of moving object
If subcarrier multiplexing is used to extend reach, then transmission reach is improved, but device complexity increases
Solution Approach 1:
The patent describes a universal transponder design that can operate in multiple modes: single-carrier mode, multi-carrier mode with different numbers of subcarriers, and different modulation formats. This multi-functionality allows a single device type to handle various transmission reach requirements without requiring separate specialized equipment for each configuration.
Solution Approach 2:
The system achieves reach extension by dynamically changing parameters such as symbol rate, number of subcarriers, and modulation format. The network management system configures these parameters to optimize transmission reach while managing the complexity through standardized parameter sets rather than custom configurations.
3Productivity
If adaptive modulation and subcarrier configuration are implemented, then spectral efficiency is improved, but control complexity increases
Solution Approach 1:
The network management system monitors channel conditions and provides feedback to adjust modulation formats and subcarrier configurations. This feedback mechanism enables the system to adapt to changing network conditions and optimize spectral efficiency while managing control complexity through automated decision-making based on measured performance.
Solution Approach 2:
The system pre-configures multiple modulation format and subcarrier combinations that can be quickly deployed based on network conditions. This preliminary preparation of configuration options allows for rapid adaptation to different scenarios without requiring complex real-time calculations, thereby reducing control complexity.
Data Source
AI summary
A disclosed method for extending reach in an adaptive optical network may include selecting, for an optical channel having a given target distance and a given maximum data rate, the modulation format having the highest spectral efficiency among modulation formats supported in the adaptive optical network that are suitable for optical channels having the given target distance and the given maximum data rate, determining a symbol rate for the optical channel dependent on characteristics of transmission media for the optical channel, determining a number of subcarriers for the optical channel corresponding to the determined symbol rate, and activating subcarrier multiplexing (SCM) for the optical channel. Activating SCM may include configuring transponders to transmit or receive the traffic in the optical channel using the selected modulation format and the determined number of subcarriers. The method may be implemented by a network management system of the optical network.