OPTIMAL PLACEMENT OF GATEWAY BASED ON GREEDY TECHNIQUE IN MULTI-HOP VEHICLE INTERNET ACCESS

Now a day's Vehicular AdHoc Network (VANET) is an emerging technology. Mobility management is one of the most challenging research issues for VANETs to support variety of intelligent transportation system (ITS) applications. VANETs are getting importance for inter-vehicle communication, because they allow the communication among vehicles without any infrastructure, configuration effort, and without the high costs of cellular networks. The access is provided by Internet gateways located on the site of roadside and the packet routing scheme is based on a multichannel medium access control protocol called VMAC using time division multiple access. We propose a graph model to characterize the observed mobility pattern. Then the gateway deploymentproblem is transformed into a vertex selection problem in a graph. By reducing it the minimum vertex coverage problem, we show the gateway deployment problem is NP-complete, so a heuristic algorithm MobGDeploy is proposed to search greedily the optimal deployment points. Extensive simulations are carried out to evaluate the performance, and the results show that the proposed algorithm out performs others.