Survivability Analysis Of Hybrid Optical And Wireless Access Network

With the rapid development of high-speed access network, end users can get faster and higher quality of service. However, due to the natural disasters or other unpredictable factors, access network may also be damaged, and make huge losses to the users. When disasters occur frequently and failure cannot be repaired, service interruptions are devastating and may result in significant economic losses. Therefore, how to avoid service disruptions, improve network survivability, and reduce the losses to a minimum has increasingly become an issue of concern.Network survivability is becoming a key issue in Passive Optical Networks (PONs). In conventional PONs, optical protection is applied to improve the network survivability. However, optical protection may be considered cost-prohibitive for cost-sensitive access networks. Besides, fiber and wireless access technology are the widely used access technology, both of them has their advantages and disadvantages. Fiber access technology has huge capacity, long transmission distance and less susceptible to interference. Furthermore, the cost is gradually declining. However, the fiber access method is singleness. Wireless access technology has flexible access method and free from the constraints of geography, but susceptible to interference.Based on the two aspects above, I propose two novel hybrid optical and wireless access networks. In this paper, by establishing wireless links among ONUs, we propose a novel wireless bypass-based protection method which has two schemes:intra-domain wireless bypass and inter-domain wireless bypass. The other hybrid optical and wireless access network is created by adding wireless Mesh module for the node of the PON, and these nodes form a wireless Mesh network. According to the difference of the nodes which form the wireless Mesh network, I propose three different network architectures:Terminal Mesh, ONU Mesh and Hybrid Mesh.Further, I present the survivability model of wireless bypass-based network architecture and the hybrid wireless Mesh-based network architecture, respectively. Then evaluate the survivability models by means of probabilistic analysis and Matlab simulation. According to the wireless bypass-based network, by taking both optical and wireless segments into account simultaneously, the simulation present that this network architecture has higher network survivability. We also compared the survivability with full optical protection, and our results highlight that the bypass-based protection method performs an improvement in survivability. In addition, we quantitatively analyze the impact of probability of fiber link failure, wireless bypass links and wireless bypass distance on the network survivability. According to the wireless Mesh-based network, I further refine the parameters of the connectivity. Considering the length of the fiber link from the microcosmic to the disaster probability from the macroscopic, I establish a survivability model which is reliable and reflect the real situation. Then I analyze the three different architecture schemes by Matlab simulation from horizontal and vertical respectively. The results of the analysis show that the wireless Mesh-based networking has a higher network survivability compared with the protection of the all-fiber-based network networking, and the wireless access can provide a more flexible access schemes for end-user. Finally, compared the three wireless Mesh-based network, the hybrid networking has the highest survivability.