Wavelength Selective Switch Protection Switching
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Solution Overview
Problem
Current optical solutions for mobile backhaul networks are costly and complex, with high latency and inefficient use of bandwidth, particularly in handling protection switching across interconnecting nodes in radio access networks.
Innovation Solution
An optical communications network with an interconnecting node that uses wavelength selective switches to establish and switch traffic paths between access nodes and a hub node without altering predetermined wavelength configurations, enabling efficient protection switching and reducing the need for monitoring and complex fault detection at the interconnecting node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protection switching is implemented across interconnecting nodes in optical networks, then network reliability is improved, but device complexity increases due to the need for fault monitoring and rapid communication at each node
Solution Approach 1:
The patent divides the optical network into distinct segments: access nodes with full protection switching capability, interconnecting nodes with fixed wavelength routing, and hub nodes with protection switching capability. This segmentation allows protection switching to be implemented only where necessary (at access and hub nodes) rather than at every interconnecting node, reducing overall device complexity while maintaining network reliability.
Solution Approach 2:
The patent extracts the fault monitoring and protection switching functions from interconnecting nodes and concentrates them at access nodes and hub nodes. Interconnecting nodes are left with simple fixed wavelength routing, removing the complexity of fault monitoring and rapid communication from these intermediate nodes while preserving end-to-end protection switching capability.
2Reliability
If wavelength selective switches are configured to handle protection switching at every node, then protection capability is improved, but configuration complexity and cost increase
Solution Approach 1:
The patent applies local quality by giving different functional characteristics to different nodes in the network. Access nodes and hub nodes are equipped with configurable wavelength selective switches for protection switching, while interconnecting nodes use fixed wavelength routing. This localized differentiation optimizes the network by providing protection capability only where it is needed, rather than uniformly across all nodes.
Solution Approach 2:
The wavelength selective switches at access nodes and hub nodes serve multiple functions: they handle both working traffic routing and protection switching operations. This multi-functionality reduces the need for separate dedicated protection switching equipment at each node, simplifying the overall system configuration while maintaining robust protection capability.
3Device complexity
If fixed preconfigured wavelength selections are used at interconnecting nodes, then device complexity is reduced, but adaptability to different traffic patterns decreases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the wavelength routing at interconnecting nodes during network setup. The working and protection wavelengths are assigned and fixed in advance at these intermediate nodes, eliminating the need for dynamic reconfiguration during operation. This preliminary configuration simplifies the interconnecting nodes while the access nodes and hub nodes retain adaptability through their configurable wavelength selective switches.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution simplifies protection switching across multiple access nodes, reduces costs by eliminating the need for complex monitoring and fault detection at the interconnecting node, and enhances network scalability and efficiency by allowing bidirectional optical rings to be interconnected, thus meeting stringent latency and capacity requirements.
Implementation Method 1
A working wavelength selective switch is provided to select which wavelengths are coupled optically between the hub working optical path and either of the first and second working optical paths
Implementation Method 2
a protection wavelength selective switch is provided to select which wavelengths are coupled optically between the hub protection optical path and either of the first and second protection optical paths
Data Source
AI summary
An optical communications network has an interconnecting node (100) coupled in between at least one hub node (130) and at least first (140) and second (150) access nodes, to provide working and protection optical paths. The interconnecting node has a working wavelength selective switch (110) to select which working wavelengths are coupled. A corresponding protection wavelength selective switch (120) is also provided for the protection wavelengths. In the event of detection of a fault, protection switching (230) is carried out at the access node and the hub node without altering the selections made by the wavelength selective switches in the interconnecting node. Thus protection schemes across the interconnecting node for more than one access node can be handled. By not needing to alter wavelength selections at the interconnecting node during protection switching operation, the complexity and thus costs can be reduced.