Fibre Optic Access Network Protection via Rate Negotiation
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Solution Overview
Problem
Fibre optic access networks face challenges in maintaining high availability and cost-effectiveness due to the need for active equipment like amplifiers on protection fibre paths, which are costly and require different lengths and transmission rates than main fibre paths, leading to potential communication failures due to excessive requirements on optical transceivers.
Innovation Solution
Implementing a method in Optical Network Units (ONUs) and Optical Line Terminals (OLTs) that detect faults in the main fibre path and negotiate a transmission rate over a backup path, allowing communication to continue at a reduced rate, even if the backup path is of lower standard and not capable of supporting the same transmission rates as the main path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active equipment such as amplifiers is installed along the protection fibre path to amplify and restore the signal, then the protection capability is improved, but the operational cost and maintenance complexity increase significantly
Solution Approach 1:
The patent uses passive optical components (splitters, couplers) instead of expensive active amplifiers to achieve signal distribution on the protection path. These passive components are cheaper, have no power requirements, and require minimal maintenance, directly resolving the contradiction between protection capability and operational cost.
Solution Approach 2:
The patent replaces active electronic amplification systems with passive optical signal distribution using splitters and couplers. This substitution eliminates the need for power-consuming active equipment while maintaining the protection function, addressing both the reliability improvement and cost reduction.
2Reliability
If the protection fibre path is made much longer than the main fibre path to provide adequate coverage, then the protection area is improved, but the transmission requirements become excessive and difficult to achieve with low cost optics
Solution Approach 1:
The patent segments the protection fibre path into multiple sections using passive optical splitters and couplers. This allows the long protection path to be divided into manageable segments, each with feasible transmission requirements, while collectively providing comprehensive protection coverage that would be impossible with a single long-link transmission.
3Adaptability or versatility
If the main fibre path and the protection fibre path are made of different lengths, then the protection flexibility is improved, but the optical transceiver requirements become different and more complex
Solution Approach 1:
The patent designs the system so that a single optical transceiver model can serve both the main path and protection path despite their different lengths. The passive optical components enable the protection path to accommodate various lengths without requiring different transceiver specifications, achieving universality and reducing device complexity.
4Ease of manufacture
If the transmission rate on the protection fibre path is reduced to accommodate longer distances, then the feasibility is improved, but the service quality deteriorates
Solution Approach 1:
The patent implements dynamic rate negotiation between the ONU and OLT when switching to the protection path. The system can adaptively adjust the transmission rate based on the actual protection path conditions, allowing feasible operation on longer paths while maximizing the available bandwidth and maintaining the highest possible service quality.
Data Source
AI summary
An Optical Network Unit, ONU, and an Optical Line Terminal, OLT, as well as a respective method therein, are provided for enabling the ONU to communicate with the OLT. The ONU and at least one OLT are comprised in a passive fibre optic access network. The passive fibre optic access network comprises two fibre paths through the network, a main fibre path and a back-up fibre path, connecting the ONU with the OLT. When a fault is detected in the main fibre path is detected, transmission rate negotiation is performed between the ONU and the OLT over the back-up path. When a transmission rate is agreed upon between the ONU and the OLT during said transmission rate negotiation with regard to communication over the back-up path, the communication between the ONU and the OLT is executed using the agreed transmission rate over the back-up path.