Optical Ring Network Protection Using Wavelength Assignment Tables
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Solution Overview
Problem
Conventional optical communication networks with ring structures face high technical complexity and inflexibility in managing multi-wavelength signals for protection against connection failures, requiring complex optical switching tools and matrices that increase with the number of communication channels.
Innovation Solution
The implementation of a method where each node in the optical communication network maintains a wavelength assignment table to map working wavelengths to corresponding protection wavelengths, allowing nodes to dynamically reroute signals upon failure detection using tunable transceivers and colorless reconfigurable optical add/drop multiplexers, reducing complexity and enhancing flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical switching tools and matrices are used to manage multi-wavelength signals for protection, then protection against connection failures is achieved, but device complexity increases considerably with the number of communication channels
Solution Approach 1:
The patent segments the protection mechanism by implementing protection switching at the add-drop multiplexer level rather than requiring full network-wide optical switching matrices. Each ADM independently handles protection for its local connections, dividing the complex global protection problem into manageable local segments that don't require extensive cross-connect capabilities
Solution Approach 2:
The patent introduces an intermediary control mechanism that uses electronic processing and control signaling to manage protection switching, rather than relying solely on complex optical switching matrices. The control system coordinates wavelength assignment and switching decisions, acting as an intermediary between failure detection and physical switching actions
2Reliability
If complex optical switching matrices are deployed to handle all wavelengths at each node, then protection coverage is comprehensive, but ease of operation deteriorates due to difficulty in managing and reconfiguring the system
Solution Approach 1:
The patent implements dynamic wavelength assignment where protection wavelengths are not fixed but are assigned on-demand based on actual traffic patterns and failure conditions. The system can dynamically adjust which wavelengths use protection paths, allowing flexible adaptation to changing network conditions without manual reconfiguration of fixed switching matrices
Solution Approach 2:
The system changes operational parameters by allowing wavelengths to switch between working and protection modes based on detected failures. The wavelength assignment tables can be dynamically updated to reflect changing protection needs, enabling the network to adapt its protection characteristics without physical reconfiguration
3Reliability
If each node is equipped with optical switching tools for the complete set of wavelengths, then protection capability is maximized, but manufacturing precision and implementation difficulty increase due to high technical complexity
Solution Approach 1:
The patent makes the add-drop multiplexers universal by enabling them to handle both working and protection wavelengths through dynamic reconfiguration. Rather than requiring specialized protection switching hardware at each node, the existing ADM infrastructure is made multi-functional through software-controlled wavelength assignment, eliminating the need for separate protection switching matrices
Solution Approach 2:
The patent uses wavelength assignment tables that can be copied and distributed across multiple nodes to ensure consistent protection behavior. The control system can replicate configuration data across the network, allowing nodes to independently implement protection switching based on copied configuration information rather than requiring complex point-to-point control connections
Data Source
AI summary
The invention relates to an optical communication network (1) comprising a plurality of nodes (2) connected to each other by means of optical fibers (3) in a ring structure, wherein optical signals are transported at working wavelengths (λw) in a first direction in said ring structure and wherein optical signals are transported at protection wavelengths (λp) in a second direction that is opposite to the first direction in said ring structure, wherein for each node (2) at least one wavelength assignment table (WAT) is provided, wherein to each working wavelength (λw) a corresponding protection wavelength (λp) is assigned, wherein in case of a detected connection failure in said ring structure each node (2) which loses at least one connection performs for all working wavelengths (λw) affected by said connection failure a lookup in its wavelength assignment table (WAT) to determine the respective protection wavelength (λp) and tunes lasers of transceiver units to the determined protection wavelengths (λp).