Optical Signal Assignment in Mixed-Grid Transparent Networks
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Solution Overview
Problem
In transparent optical networks with mixed channel spacings, existing routing strategies lead to significant bandwidth under-utilization due to fragmentation and lack of wavelength continuity between adjacent links, resulting in inefficient signal assignment.
Innovation Solution
A method to assign signals to central wavelengths by determining the widest and narrowest channel spaced grids, weighting central wavelengths based on occupation and alignment, and combining weights to optimize signal routing across multiple links with different channel spacings, using a bonus value to minimize bandwidth waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different channel spaced grids are used in transparent optical network links, then the network can accommodate various filtering technologies and generations of wavelength selective switches, but wavelength continuity between adjacent links is not guaranteed and bandwidth is significantly under-utilized
Solution Approach 1:
The patent segments the optical bandwidth into multiple grids with different channel spacings (e.g., 100 GHz, 50 GHz, 25 GHz, 12.5 GHz), allowing each link to use the most suitable grid for its filtering capabilities while maintaining overall network compatibility. This segmentation enables flexible adaptation to different node capabilities without requiring uniform grid spacing across the entire network.
Solution Approach 2:
The patent introduces a new dimension for wavelength selection by considering both grid alignment and channel spacing simultaneously. Instead of choosing wavelengths based on a single grid, the method evaluates multiple grids with different spacings and selects optimal wavelengths that are aligned across the widest possible number of grids, thereby maximizing bandwidth utilization while maintaining compatibility with various filtering technologies.
2Ease of operation
If routing strategies are used to route signals through mixed grids, then signals can be transmitted across links with different channel spacings, but significant stranding of bandwidth occurs
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing alignment information between different grids before signal routing occurs. The system determines in advance which wavelengths are aligned across multiple grids and uses this pre-computed information during routing decisions, enabling optimal wavelength selection that minimizes bandwidth stranding while maintaining routing flexibility.
Solution Approach 2:
The patent implements feedback mechanisms where the routing algorithm continuously monitors bandwidth utilization and alignment status across mixed grids. Based on this feedback, the system dynamically adjusts wavelength assignments and routing paths to minimize stranding, ensuring that bandwidth is efficiently utilized while maintaining operational flexibility in routing signals through heterogeneous networks.
Data Source
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AI summary
A method of assigning a signal (10) to a central wavelength (5) through a path crossing successive links (1, 2, 3, 4) in a transparent optical network comprising nodes connected by a plurality of links, each link (1, 2, 3, 4) using an optical grid with a constant channel spacing, comprising the steps of: - determining, through the network, the widest channel spaced grid (4) and the narrowest channel spaced grid (1); - parting, at each link (1, 2, 3, 4) through said path, the total optical bandwidth into central wavelengths spaced and aligned with the narrowest channel spaced grid (1); - weighting, at each link (1, 2, 3, 4) through said path, each central wavelength with a weight indicative of the occupation of said central wavelength at said link and of the alignment of said central wavelength with said widest channel spaced grid (4); - combining, the weights encountered through said path for each central wavelength; and - assigning said signal to be routed to a central wavelength with an optimal combined weight.