Dynamic Modulation Format Assignment in Optical Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical networks face challenges in efficiently provisioning virtual optical networks with guaranteed availability and maximum spectral efficiency, as they often require over-provisioning and have limited spectral utilization due to fixed channel spacing and modulation formats that do not optimize data rate and spectral efficiency.
Innovation Solution
The method involves identifying nodes and optical routes in a virtual optical network, determining the signal-to-noise ratio (SNR) probability density function, setting an SNR threshold for desired availability, and selecting modulation formats that maximize spectral efficiency, such as probabilistically shaped or time-domain hybrid quadrature amplitude modulation, to assign the optimal modulation format for data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed channel spacing and modulation formats are used in optical networks, then network provisioning is simplified, but spectral efficiency is limited and over-provisioning is required
Solution Approach 1:
The patent implements dynamic modulation format assignment where the modulation format (e.g., QPSK, 16-QAM, 64-QAM) is selected based on real-time SNR measurements and availability requirements. This dynamic adaptation allows the system to optimize spectral efficiency for each optical route while maintaining guaranteed availability, eliminating the need for fixed, conservative provisioning
Solution Approach 2:
The system changes the modulation format parameter based on SNR threshold calculations. By determining the PDF of SNR for each optical route and calculating appropriate SNR thresholds based on desired availability (e.g., 0.999), the system selects modulation formats that maximize spectral efficiency while meeting availability guarantees, thereby resolving the contradiction between provisioning simplicity and spectral efficiency
2Reliability
If over-provisioning is implemented to guarantee availability, then reliability is improved, but network resource utilization decreases
Solution Approach 1:
The system employs feedback mechanisms by continuously measuring SNR on optical routes and using this information to dynamically adjust modulation format assignments. This feedback loop ensures that availability guarantees are met based on actual channel conditions rather than conservative over-provisioning, thereby maximizing network resource utilization while maintaining reliability
Solution Approach 2:
The system performs preliminary calculations of SNR probability density functions and SNR thresholds for different availability levels (e.g., 0.99, 0.999, 0.9999) before actual data transmission. This preliminary analysis enables the system to pre-determine optimal modulation formats that satisfy availability requirements without requiring over-provisioning, thus improving resource utilization while guaranteeing reliability
Data Source
AI summary
Systems and methods for identifying a pair of nodes of a plurality of nodes of a virtual optical network (VON); identifying i) an optical route between the pair of nodes and ii) a desired availability of the optical route; determining a probability density function (PDF) of a signal-to-noise ratio (SNR) of a signal of the optical route; determining a SNR threshold such that an integration of the PDF of the SNR of the signal above the SNR threshold corresponds to the desired availability of the optical route; determining a plurality of spectral efficiencies that corresponds to the SNR threshold, each spectral efficiency of the plurality of spectral efficiencies associated with a respective modulation format of a plurality of modulation formats; and identifying a particular modulation format of the plurality of modulation formats that corresponds to a maximum spectral efficiency of the plurality of spectral efficiencies.