Hierarchical Optical Access Network with Switches
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Solution Overview
Problem
Conventional GE-PON systems face limitations in transmission distance due to optical splitter losses, security issues due to signal encryption vulnerabilities, and communication interference from malicious or faulty ONUs.
Innovation Solution
Implementing a hierarchical optical access network with optical switches that forward downlink and uplink signals based on information from the center terminal, allowing for precise signal routing and reducing the need for optical splitters, thereby increasing transmission distance, enhancing security, and preventing communication interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If optical splitters are used to connect multiple ONUs to the OLT, then the network can support multiple users, but the transmission distance is limited due to optical power loss
Solution Approach 1:
The patent divides the optical network into multiple stages, with optical switches performing coarse-grained spatial switching in earlier stages and optical splitters performing fine-grained distribution in later stages. This segmentation allows the system to support multiple ONUs while maintaining longer transmission distances by reducing the burden on individual optical splitters.
Solution Approach 2:
The patent introduces optical switches as intermediary devices between the OLT and optical splitters. These switches act as mediators that perform preliminary spatial switching, reducing the number of ports required at each splitter and thereby reducing total optical loss while maintaining the ability to serve multiple ONUs.
2Area of stationary object
If optical splitters are used to distribute signals to multiple ONUs, then network coverage is expanded, but security is compromised because all ONUs receive all signals
Solution Approach 1:
The patent segments the signal distribution process into multiple stages: optical switches perform coarse-grained spatial switching to direct signals to specific groups of ONUs, while optical splitters perform fine-grained distribution within those groups. This multi-stage segmentation ensures that each ONU receives only the signals intended for it, maintaining security while expanding network coverage.
Solution Approach 2:
The patent applies different switching characteristics to different parts of the network. Optical switches provide dedicated, secure connections for specific signal streams, while optical splitters provide shared distribution for localized groups. This local differentiation of quality ensures security is maintained where needed while coverage is expanded where appropriate.
3Quantity of substance
If a large number of optical splitters are deployed to support many ONUs, then user capacity increases, but system cost increases
Solution Approach 1:
The patent merges the functions of optical switching and optical splitting into a unified hierarchical system. Optical switches and optical splitters work together in a coordinated manner, with the switch performing coarse-grained routing and the splitter performing fine-grained distribution. This merging of functions reduces the total number of components needed while maintaining the ability to support many ONUs.
Solution Approach 2:
The patent creates a universal hierarchical architecture that can accommodate varying numbers of ONUs by combining optical switches and optical splitters in different configurations. This multi-functional system can be scaled to support different network sizes without requiring complete redesign, thereby reducing overall system cost while maintaining high user capacity.
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
The solution enables longer transmission distances, improved security by ensuring signals reach only intended ONUs, and prevents communication interference, making the network more economical and suitable for broadband services.
Implementation Method 1
an optical switch forwards a downlink signal transmitted from the center terminal to one of the remote terminals specified by the center terminal based on information from the downlink signal, and forwards an uplink signal transmitted from the remote terminal specified by the center terminal to the center terminal based on the information from the downlink signal
Implementation Method 2
Implementing a hierarchical optical access network with optical switches that forward downlink and uplink signals based on information from the center terminal, allowing for precise signal routing and reducing the need for optical splitters, thereby increasing transmission distance
Data Source
AI summary
An optical access network method, an optical access network and an optical switch for an optical access network, capable of solving all the three problems in the conventional GE-PON: transmission distance problem, security problem and communication interference problem. The optical access network comprises an OLT, a plurality of ONUs and one or more stages of optical switches, which are connected one another. In the direction from the OLT to the ONU, each frame (packet) transmitted from the OLT to one of the ONUs is checked so that only the destination ONU specified in the frame (packet) is connected to the OLT. In the direction from the ONU to the OLT, a control message transmitted from the OLT to one of the ONUs is checked so that only one ONU which has been given a transmission allowance from the OLT is connected to the OLT with respect to each frame (packet).