PON Link Failure Processing for Ethernet ONU Collision Prevention
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Solution Overview
Problem
In PON systems using Ethernet devices, 10 G Ethernet ONUs face challenges in transmitting L2 data signals due to link failure detection limitations, leading to failed uplink communications when multiple ONUs transmit simultaneously.
Innovation Solution
Implementing a communication device with an Ethernet controller and link failure processing unit that manages data transmission based on link failure notifications, allowing ONUs to terminate or start data transmission as needed to prevent collisions and recover from link failures, enabling uplink communication using standard Ethernet devices in PON topology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ONUs transmit data signals simultaneously in a PON system using standard Ethernet devices, then uplink communication capacity is improved, but link failure detection limitations cause transmission collisions and communication failures
Solution Approach 1:
The OLT transmits gate messages to multiple ONUs in advance, allocating specific transmission time periods and start time points before the actual data transmission begins. This preliminary scheduling prevents collisions by ensuring each ONU transmits only during its assigned time slot, resolving the contradiction between enabling simultaneous uplink communication and preventing transmission conflicts.
2Adaptability or versatility
If 10 G Ethernet ONUs use standard link failure detection functions, then device compatibility is improved, but the detection function causes false link failure recognition when multiple ONUs transmit simultaneously
Solution Approach 1:
The gate message acts as an intermediary control mechanism that coordinates transmission between multiple ONUs and the OLT. By requiring ONUs to wait for and respond to gate messages before transmitting data signals, the system prevents simultaneous transmissions that would cause false link failure detection, while still allowing standard Ethernet link failure detection functions to operate correctly.
3Ease of manufacture
If the OLT shares a single optical fiber among multiple ONUs to reduce installation costs, then cost and occupation area are reduced, but transmission control complexity increases
Solution Approach 1:
The OLT segments the shared optical fiber transmission medium by allocating specific time periods and time slots to different ONUs for data transmission. This time-division segmentation allows multiple ONUs to share the same physical fiber infrastructure without interference, reducing installation costs while maintaining manageable transmission control through structured time allocation.
Data Source
AI summary
A communication device including a first communication device and a plurality of second communication devices in an optical access system in which a first communication device and the plurality of second communication devices perform communications with each other under a time division multiple access scheme includes an Ethernet controller configured to implement the communications as Ethernet (registered trademark) communications, and a link failure processing unit configured to output, in response to reception of a link failure notification for notifying occurrence of a link failure in the communications from the first communication device, a termination instruction to terminate data transmission when the communication device is performing the data transmission to the first communication device, and a start instruction to start the data transmission after recovery from the link failure when the communication device is not performing the data transmission to the first communication device.