International Journal of Network Management
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The survivability of wireless access networks has become a critical issue due to the rapidly increasing dependence on wireless mobile services. However, little emphasis has been placed on understanding and improving the survivability of wireless access networks. In this dissertation, a multilayer survivability framework is presented in order to facilitate the development of effective techniques for building survivable wireless access networks. The results of a simulation-based survivability analysis are given to determine the impact of various failure scenarios in wireless access networks. This dissertation proposes new techniques for survivable wireless access network design. The goal is to provide an effective solution for wireless access network design that satisfies traffic and survivability requirements while minimizing the network design cost of the wireless backhaul network. Three different approaches to creating a survivable network topology for second generation wireless access networks are considered namely: (1) a mesh-based restorable network, (2) a multi-ring network, and (3) a hybrid mesh-ring network. Network design problems are formulated as mathematical optimization models for each of the three approaches. A novel aspect of the proposed work is the incorporation of the effect of user mobility after a failure in the network design model. Numerical results show that, among the three different network design approaches considered, a mesh-based restorable network design is the most cost-efficient. A two-phase design methodology is developed to solve the mesh-based restorable network design problem. The first phase provides a minimum-cost, initial network design that can satisfy the traffic requirements of the network. The second phase provides an incremental approach to augmenting the minimum cost network topology from phase one in order to satisfy survivability requirements. The proposed two-phase model for a mesh restorable network design can be easily applied to both new and existing wireless access networks to improve their survivability.This dissertation also proposes an efficient heuristic algorithm to solve the mesh-based network design problem using a minimum-cost routing technique. The proposed heuristic can efficiently find near-optimal solutions compared to the solutions obtained from a standard optimization technique for small problem-size networks. More importantly, the algorithm is shown to scale to solve the mesh-based network design problem in large problem-size networks within a reasonable amount of time. Lastly, the proposed two-phase mesh network design model and heuristic algorithm can be applied to the design of emerging third-generation wireless access networks. Experimental results show that the two-phase mesh network design model and heuristic algorithm yield reasonable solutions.