K-Alternate Channel Selection for Flexible Optical WDM Spectrum Allocation
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Solution Overview
Problem
Current optical WDM networks with fixed channel spacing are inefficient in spectrum utilization due to fixed spectrum allocation, which does not adapt to varying line rates, leading to suboptimal spectral efficiency and scalability issues in solving the Routing, Wavelength Assignment, and Spectrum Allocation (RWSA) problem.
Innovation Solution
The K-alternate channel selection procedure, which involves finding optimal line rates, selecting channels with sufficient spectrum, and determining K-distinct shortest routes to minimize spectrum usage by prioritizing lower wavelengths and optimizing spectrum allocation in flexible optical WDM networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed grid networks with standardized channel spacing are used, then network simplicity and standardization are improved, but spectral efficiency deteriorates because fixed spectrum allocation cannot adapt to varying line rates
Solution Approach 1:
The patent implements flexible channel spacing that adapts to different line rates dynamically. Instead of fixed grid spacing, the system allows variable channel spacing (e.g., 100 GHz, 50 GHz, or custom spacing) based on the specific bandwidth requirements of each connection, enabling optimal spectrum utilization while maintaining network simplicity through automated configuration.
Solution Approach 2:
The invention changes the fundamental parameter of channel spacing from fixed to variable. The system allows operators to configure different channel spacing values depending on the line rate and spectrum requirements, transforming the rigid fixed grid into a flexible parameter that can be optimized for each specific deployment scenario.
2Quantity of substance
If flexible channel grid is implemented to increase spectral efficiency, then spectral efficiency is improved, but the complexity of solving RWSA problem increases exponentially with system size
Solution Approach 1:
The patent segments the RWSA problem into multiple independent sub-problems: first determining optimal line rates, then selecting channels with sufficient spectrum, and finally routing connections. This segmentation allows each sub-problem to be solved independently and efficiently, avoiding the exponential complexity of solving the entire problem simultaneously while maintaining high spectral efficiency.
Solution Approach 2:
The invention performs preliminary actions by first determining the optimal set of line rates and then pre-calculating channel selections before final routing. This preliminary processing reduces the search space for the actual routing decision, transforming an exponentially complex problem into a polynomial-time solvable problem while preserving optimal spectral efficiency.
3Loss of time
If K-alternate channel selection procedure is used to reduce computation time, then time required to solve RWSA problem is reduced from exponential to polynomial, but solution quality may degrade marginally
Solution Approach 1:
The patent applies partial action by considering only the K shortest paths instead of exhaustively searching all possible routes. This partial exploration approach provides sufficiently good solutions in polynomial time, achieving a practical trade-off between computation time and solution quality. The system selects channels and routes that provide adequate performance without requiring exhaustive search.
Data Source
AI summary
A method implemented in an optical flexible wavelength division multiplexing FWDM network includes finding a first channel out of available channels with sufficient spectrum on a given route out of available channels in an optical FWDM network; finding a second channel at a lower wavelength out of the available channels for minimizing total spectrum on the given route; selecting a channel out of the available channels on K-distinct shortest routes; and finding line rates of channels using a predetermined channel selection.