WDM Path Selection with Physical Impairment Checks
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Solution Overview
Problem
Existing WDM optical networks do not fully consider the mutual influence of service performance between different wavelengths, leading to bit errors or service interruptions during network expansion, as they fail to account for physical impairments such as crosstalk and non-linearity.
Innovation Solution
A path selecting method and apparatus that computes end-to-end paths for new services considering network topology and wavelength constraints, collects physical impairment information including gain reference spectra of optical amplifiers, and performs impairment checks to ensure performance meets preset requirements, thereby selecting paths that minimize interference between wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wavelength assignment is performed from two sides to the middle in mixed-rate transmission scenarios, then network expansion is simplified, but service performance mutual influence is not fully considered leading to bit errors or service interruptions
Solution Approach 1:
The patent performs preliminary impairment checks and performance computations before finalizing wavelength assignment. By calculating physical impairment effects and service performance metrics in advance, the system identifies potential conflicts between wavelengths before network expansion is completed, preventing bit errors and service interruptions while maintaining expansion simplicity
Solution Approach 2:
The patent implements a feedback mechanism where service performance is computed based on physical impairment information, and this performance data feeds back into the wavelength assignment decision process. The system continuously monitors and adjusts wavelength assignments to maintain service performance requirements, resolving the contradiction between expansion simplicity and service reliability
2Reliability
If physical impairment information is fully considered in path selection, then service performance mutual influence is accounted for, but computation complexity and processing time increase
Solution Approach 1:
The patent segments the impairment check process into distinct modules: physical impairment information collection, performance computation based on impairment data, and path selection based on performance results. This modular approach allows comprehensive impairment consideration while managing computation complexity through structured, reusable components
Solution Approach 2:
The patent transforms physical impairment information into service performance parameters through standardized computations. By converting complex physical impairment data into manageable performance metrics, the system achieves accurate service performance assessment without excessive computation complexity
Data Source
AI summary
Embodiments of the present invention disclose a path selecting method and apparatus. The method includes: computing an end-to-end path for a newly added service according to network topology and a wavelength constraint, and assigning a wavelength to the path; computing performance of each existing service and performance of the newly added service in a network according to physical impairment information collected in the network, where the physical impairment information includes a gain reference spectrum of each optical amplifier in the network; and performing impairment check on performance of each service, and performing path selection for the newly added service according to a result of the impairment check. The apparatus includes a path computation module, a performance computation module and an impairment check module. According to the embodiments, efficiency of network update or rerouting is improved.