Study On Multi-Link Failure Detection And Localization Schemes Of Optical Transport Network For High-speed Railway

Optical transport network of high-speed railway has been the foundation for ensuring the safety of high-speed railway operation.Aiming to provide more rates and more kinds of communication channels and transmit services with multiple different security levels,the optical transport network of high-speed railway presents a trend of development with complicated topology and high capacity bandwidth.On one hand,complicated network topologies increase the probability of multi-link failures;on the other hand,high capacity link bandwidth increases the loss caused by failures.Existing network structures and protections of high-speed railway optical transport network are completely resistant to overcoming single-node and single-link failure.However,it is still difficult to localize multi-node and multi-link failures.The impact of multi-node and multi-link failures on the reliability of optical transport network is enormous.In order to avoid the huge loss of multi-node and multi-link failures bringing to the railway operation,the paper focuses on the multi-node and multi-link failures detection and localization schemes applicable to the high-speed railway optical transport network.The main contents of this paper are as follows:Firstly,the sources of failures and the mechanism of failure occurrence in the optical transport network of high-speed railway are analyzed in this paper.Based on these above analysis,the evaluation standards are concluded for classification of failures in the high-speed railway optical transport network,and a set of failure assessment indicators for high-speed railway optical transport network is established.Apart from this,an optical network status monitoring function is proposed which can quantify fault alarm information.Secondly,Binary Tree Decomposition Localization Algorithm based on Tree Decomposition Localization Algorithm is proposed for multi-link failures in bureau-level networks of high-speed railway optical transport network.In this algorithm,the alarm information in the network is collected first,and then the binary tree decomposition algorithm is used to partition the network into subnetworks with single-link failure.The improved m-tree algorithm in each subnetwork is operated to locate failures accurately afterwards.Finally,multi-link failures location is realized.Through simulation and verification,BTDL algorithm enables a gain in terms of monitoring cost of around 12.4%compared to the TDL algorithm.BTDL algorithm can always maintain a failure localization accuracy that is not inferior to that of the TDL algorithm under the condition that the monitoring cost is lower than that of the TDL.Thirdly,Parallel Clustering-limited-perimeter Vector Matching Fault-localization Protocol(PC-LVM)is proposed for multi-link failure localization in the head office level network of high-speed railway optical transport network.PC-LVM combines the Parallel Limited-perimeter Vector Matching Fault-localization Protocol(PLVM)based on Limited-perimeter Vector Matching Fault-localization Protocol(LVM)with Clustering Failure Localization Algorithm.PC-LVM realizes the transition from multi-link failure localization to single-link failure localization to localize multi-link failures which LVM and Clustering Failure Localization Algorithm cannot realize.In this algorithm,the parallel limited-perimeter vector matching fault-localization protocol is used to realize the transition from multi-link failure localization to single-link failure localization and to limit the failure area of each link failure.Clustering Failure Localization Algorithm is used to achieve fast and accurate failure localization within the failure area.The simulation verifies that the algorithm can effectively reduces the average failure localization delay.