SHADOWING EFFECTS ON ROUTING PROTOCOL OF MULTIHOP AD HOC NETWORKS

Two-ray ground reflection model has been widely used as the propagation model to investigate theperformance of an ad hoc network. But two-ray model is too simple to represent a real world network. Amore realistic model namely shadowing propagation model has been used in this investigation. Undershadowing propagation model, a mobile node may receive a packet at a signal level that is below arequired threshold level. This low signal level affects the routing protocol as well as the medium accesscontrol protocol of a network. An analytical model has been presented in this paper to investigate theshadowing effects on the network performance. The analytical model has been verified via simulationresults. Simulation results show that the performance of a network becomes very poor if shadowingpropagation model is used in compare to the simple two-ray model. Two solutions have also beenproposed in this paper to overcome the effects of shadowing. One solution is a physical layer solution andthe other one is a Medium Access Control (MAC) layer solution. Simulation results show that these twosolutions reduce the shadowing effect and improve network performance