Research On A New Cross-layer Service Discovery Protocol For Ad-Hoc Network

Ad-Hoc Network is a kind of special wireless network.All nodes in the network are equal and there is no need to set any central control node.It is highly self-organized and resistant to destruction.Therefore,it is popular in military affairs,disaster rescues,remote area affairs and temporary conferences and becomes one of the hot spots in the research of wireless networks.Efficient service discovery is very important because of the dynamic topology in Ad-Hoc Network.It is not only the foundation for all nodes in the network to share their services but also one of the integrant parts in Ad-Hoc protocol stack. The purpose of this paper is to design an efficient service discovery protocol for Ad-Hoc Network so as to improve the efficiency of service discovery.Firstly,we analyze the characteristics,classification and application surroundings of existing service discovery protocols and pointe out that traditional strictly layered service discovery protocols do not adapt to Ad-Hoc Network.Then,we make a comparision between route discovery and service discovery and find that they are similar though the two discovery mechanisms are in different layers of the network.The traditional layered design distinguishes these two discovery mechanisms strictly so that these two similar mechanisms are realized and executed repeatedly.Therefore,it produces redundant control overhead and resultes low service discovery efficiency.To solve this problem,we make reference to the popular cross-layer design in Ad-Hoc Network and put forward a new service discovery algorithm that is to integrate the service discovery messages to routing discovery protocol.The algorithm will decrease redundant control overhead between layers and increase the efficiency of service discovery.In the mean time we propose a typical application example using this new algorithm to realize service discovery in Ad-Hoc Network.After filtering among routing protocols,we finally choose AODV(Ad-Hoc On-Demand Distance Vector Algorithm) routing protocol,which enjoys high bandwidth utilization and quick response to dynamic topology,to integrate service discovery messages.At last,we run simulation on the platform of OPNET(Optimal Network Engineering Tools).The results show that the new algorithm can decrease total control overhead and end-to-end delay and so it is effective.