Performance of Ad Hoc Routing Protocols in Urban Environments

Multiple wireless terminals jointly create and maintain ad hoc networks without the help of central entities. Possible applications for such networks are in urban areas to avoid additional costs for communicating over cellular networks. Whenever two nodes are not within each others proximity, they use multihop connections for data exchanges. Ad hoc routing algorithms are utilized to setup these multihop connections. Most of them have been studied with the network simulator ns-2. In contrast to the proposed scenario, simulations always utilized flat simulation environments, with all nodes within line of sight. Within this paper, we introduce the well known Walfisch-Ikegami propagation model to allow ad hoc simulations in urban areas. It allows accurate propagation predictions, but does not significantly delay computation. Following simulations in two different urban situations reveal new performance insights. Ad hoc algorithms are able to cope with this environment, but compared to simulations with flat environments the overall network performance is significantly reduced.