Optical Switch for Radio Access Network Flexibility
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Solution Overview
Problem
Current radio access networks face challenges in connecting remote radio units (RRUs) with main units (MUs) over extended geographical distances, leading to inadequate flexibility and high fiber requirements, as traditional point-to-point links are insufficient for long distances between RRU and MU.
Innovation Solution
A switch system with multiple stages, including a central stage using an Arrayed Waveguide Grating (AWG) for wavelength-based optical switching, allows dynamic connection between RRUs and MUs, enabling flexible wavelength selection and distribution across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional point-to-point optical connections are used between MU and RRU, then connection simplicity is maintained, but flexibility and adaptability are insufficient for extended geographical distances
Solution Approach 1:
The optical switching system is divided into multiple stages: first stage units perform electrical-to-optical conversion and initial wavelength assignment, a central stage performs optical switching based on wavelength, and second stage units perform optical-to-electrical conversion. This segmentation allows each stage to specialize in specific functions, achieving flexible connectivity without requiring a single complex switching device.
Solution Approach 2:
Optical wavelengths serve as intermediaries between remote radio units and main units. The first stage converts electrical signals to optical signals with specific wavelengths, which then traverse the optical network to the central stage and ultimately to the destination. This intermediary approach enables flexible routing over extended distances while maintaining signal integrity.
2Quantity of substance
If daisy-chained RRU configuration is used to reduce fiber requirements, then fiber quantity is reduced, but latency control and synchronization accuracy deteriorate
Solution Approach 1:
The system segments the signal path into dedicated point-to-point optical connections rather than daisy-chaining multiple RRUs through a single fiber. Each RRU-MU pair has its own optical pathway, eliminating the cumulative latency and synchronization issues inherent in daisy-chain configurations while still optimizing fiber usage through wavelength multiplexing.
Solution Approach 2:
The patent replaces electrical signal transmission through shared copper or fiber infrastructure with optical signal transmission through dedicated optical paths. This substitution of transmission medium and method enables precise latency control and synchronization while reducing the need for complex daisy-chain topologies.
3Adaptability or versatility
If CPRI protocol with static configuration is used, then implementation simplicity is maintained, but adaptability for dynamic network conditions is insufficient
Solution Approach 1:
The optical switching system enables dynamic reconfiguration of connections between RRUs and MUs by changing wavelength assignments and switching paths in real-time. Unlike static CPRI configurations, the system can dynamically adapt to varying traffic conditions, maintenance requirements, and network optimization goals while maintaining operational simplicity through automated control.
Solution Approach 2:
The system changes operational parameters such as wavelength assignments, connection paths, and switching configurations to adapt to different network conditions. By modifying these parameters dynamically, the system achieves versatility in handling various scenarios while the underlying optical infrastructure maintains operational simplicity through standardized interfaces and automated management.
4Reliability
If multiple fibers are deployed for each RRU-MU connection, then connection reliability is improved, but infrastructure cost and complexity increase
Solution Approach 1:
Single optical fibers are designed to carry multiple wavelength channels, each serving different RRU-MU connections. This multi-functionality allows the same physical fiber infrastructure to support multiple logical connections simultaneously, achieving connection reliability through wavelength diversity rather than physical redundancy, thereby reducing the total fiber quantity required.
Solution Approach 2:
The system uses wavelength as a variable parameter to create multiple independent communication channels within a single fiber. By changing the wavelength parameter, the system can establish different connections through the same physical medium, providing reliability through channel diversity while minimizing fiber deployment requirements.
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 provides flexible and efficient connectivity between RRUs and MUs, reducing fiber requirements and meeting strict latency requirements, while allowing for dynamic load balancing and energy optimization in radio access networks.
Implementation Method 1
A switch system with multiple stages, including a central stage using an Arrayed Waveguide Grating (AWG) for wavelength-based optical switching
Data Source
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AI summary
A switch (10) configured to connect a plurality of remote radio units (3) with a plurality of main units (5) in a radio access network. The switch comprises a first stage (30) comprising one or more first units (18) configured to receive a signal originating from a remote radio unit, and configured to output one or more spectral component having a wavelength. The switch further comprises a central stage (40) configured to receive the one or more optical wavelength, and transfer the spectral component to an output port determined by the wavelength. The switch further comprises a second stage (50) comprising one or more second units configured to receive the one or more spectral component from the central stage and output a signal towards a main unit. The first unit (18) is configured to control the wavelength of the output spectral component such that the spectral component is transferred by the central stage to a selected one of said second units (19).