Properties of Wireless Multihop Networks in Theory and Practice

Simulation and testbeds are frequently used for the validation of wireless networking protocols, but several assumptions regarding node placement, wireless signal propagation, and traffic type must be made. We compare common models with the measurements made in Berlin’s and Leipzig’s free multihop wireless networks. It is shown that the properties observed in reality are different than in commonly used models: network is connected but with low average node density; it has large number of bridges and articulation points that can compromise its connectivity; and the traffic distribution over nodes is highly asymmetrical. As an illustration of the discrepancy between reality and synthetic models, we present issues of reactive route discovery process that cannot be observed in simulation that use common placement and propagation models. This chapter focuses on the understanding of limitations of simulation methodologies. It also provides general guidelines on ways of reducing the gap between simulation theory and practice of wireless multihop networks.