Delay and Throughput in Random Access Wireless Mesh Networks

The wireless mesh networks (WMNs) are emerging as a popular means of providing connectivity to communities in both affluent and poor parts of the world. The presence of backbone mesh routers and the use of multiple channels and interfaces allow mesh networks to have better capacity than infrastructure-less multihop ad hoc networks. In this paper we characterize the average delay and capacity in random access MAC based WMNs. We model residential area WMNs as open G/G/1 queuing networks. The analytical model takes into account the mesh client and router density, the random packet arrival process, the degree of locality of traffic and the collision avoidance mechanism of random access MAC. The diffusion approximation method is used to obtain closed form expressions for end-to-end packet delay and maximum achievable per-node throughput. The analytical results indicate that how the performance of WMNs scales with the number of mesh routers and clients. We also discuss that how the results obtained for WMNs compare with well known results on asymptotic capacity of infrastructure-less ad hoc networks. The results obtained from simulations agree closely with the analytical results.