Analysis of the behavior of selfish nodes in ad-hoc networks for reduction of their impacts

Ad-hoc networks consist of wireless nodes communicating without the need for a centralized administration. In such a set-up, reliability of the communication process depends on all nodes potentially contributing to the routing of packets. In practice though, some nodes may act selfishly and refuse to forward packets. Such nodes may be overloaded, or they may merely want to save their resources, as they may not see any advantages for themselves through routing of packets. As a result of such selfish behavior, the functioning of the whole network can be drastically distressed. In this paper, we report the experimental results obtained from typical Ad-hoc networks that contain selfish nodes. The results of simulation studies, using Optimized NETwork (OPNET) software simulator, under the same settings as the experimental networks are also reported. Correlation between the two sets of results is found to be satisfactory enough to validate the simulation techniques and processes. With this validation, using similar simulation methods, the examination of a rather large Ad-hoc network is then carried out. Using the results of such analysis, we propose an approach that is based on taking into account the behavior history of the nodes in establishing the packet routing paths. The reported approach is an extension of the widely used Ad-hoc on Demand Distance Vector routing protocol. The results of simulation studies clearly show that by applying the proposed approach, significant improvements in the reliability of the Ad-hoc networks are accomplished.