Improving connectivity in vehicular ad hoc networks: An analytical study

Connectivity in vehicular ad hoc networks may degrade dramatically in sparse traffic and also high speed highways. In this paper we study a way to improve the connectivity by adding some extra nodes with higher transmission range which we call mobile base-stations. These nodes can also offer commercial services (e.g. advertisement, video, audio, etc.) to the vehicles on roads. Besides, the financial profit of those services also depends on a satisfactory connectivity. We use an equivalent M/G/infinity queuing model in order to investigate the connectivity. We further take into account the case when some vehicles do not participate in the network either because they are not equipped with wireless transceivers or some other reasons like security concerns. Moreover, connectivity in presence of fixed Road Side Units (RSUs) is also studied. Our proposed analytical model can be used to find the optimum values of the number of base-stations as well as their transmission range in order to achieve a desired degree of connectivity. (C) 2007 Elsevier B.V. All rights reserved.