Design And Simulated Implementation For Protection Algorithms In Wireless-Optical Broadband-Access Networks

With the broadband services increasing, such as IPTV, the broadband access network is experiencing a rapid development. Compared with the traditional access technologies, hybrid Wireless-Optical Broadband-Access Networks (WOBAN) provides the larger bandwidth, more flexible network control platform, higher Quality of Service (QoS) and better support for multimedia applications to meet the users’ requirements. Therefore, WOBAN is a promising architecture for access networks and it has become a hot issue in recent years.This thesis focuses on the survivability in WOBAN to design the proper protection strategies and find the optimal solution to reduce the cost of backup fibers. Considering the front-end wireless Mesh network in WOBAN is self-healing while the back-end Passive Optical Network (PON) cannot guarantee the survivability due to the tree topology, this thesis studies the protection method to resist network component failures in the back-end PON.Based on the analysis of the failure effects resulting from the exceptions of WOBAN, this thesis make the rating of the failures in network. A brief description of the survivable theories and technologies are adopted, and the consideration is taken on the protection strategy. Then, this thesis proposes a protection strategy of the coordinate between the developing backup fiber and the placement of backup ratio which aims at protections of various levels of failure effects. Firstly, according to the topology of access network, this thesis put forwards a Ring-Based Protection Algorithm (RBPA) targeting on high level failure. Then a Radio-Deployed Protection Algorithm (RDPA) is proposed combined with the RBPA algorithm at the front end of WOBAN which aims at secondary failure.The simulation and relevant analysis are introduced in order to validate the performance of the proposed protection algorithms. Based on VC++simulation software, the RBPA and RDPA algorithms are compared with the traditional algorithms. The simulation result shows that RBPA and RDPA are able to provide a suboptimal solution of developing backup fiber and placement of the backup radio. Compared with the previous protection methods in WOBAN, the algorithms proposed in this thesis can not only provide a full protection for all levels of failure conditions but also save the network cost hugely. Also, the time used to transfer the traffic affected by failure is in an acceptable range.