The Study On Ad Hoc Network Distributed Simulation On OPNET

Ad Hoc network is a new network technology in the field of wireless communication, which is being developed rapidly. It doesn’t depend on the conventional network infrastructure. Each node is both a host and a router, so the mobile node via multi-hop wireless links communicating with each other. As each node is a wireless mobile node, it can enter and leave the network at any time, the network is distributed running. Research on its distributed operating becomes a hot issue. And Network simulation technology has become one of the primary means to study network performance, and OPNET simulation platform becomes the most widely used simulation software by virtue of its precision simulation and accurate presentation of the results. This paper will research the semi-physical simulation of Ad Hoc network based on OPNET platform.Ad Hoc network can be widely used in many fields, especially in the military field. In the specific military applications, it often needs to select a master node among the whole nodes to control the entire network, and needs to update the master node alone with the change of the network topology. But Ad Hoc network cannot meet these needs as there is no different between the network nodes; we need to design an effective method to solve the problem.The SITL(System-in-the-Loop) module and HLA(High Level Architecture) interface provided by OPNET are deeply analyzed in this paper. On the basis, a design is proposed to realize semi-physical simulation based on SITL module, given the specific design and experimental design. It also analyses the function of SITL module to make communication between the physical environment and simulation environment. Meanwhile, a new algorithm is proposed based on OLSR protocol to realize that the master node can be chosen automatically. Firstly, the local routing table of each node is updated by OLSR routing protocol; Secondly, each node queries the local routing table to get the IP addresses of all the nodes; Finally master node is selected or updated according to the selection strategy. The algorithm has been realized through the transformation of MANET node model in OPNET. And finally, we use OPNET simulation platform to validate the algorithm, through analysis of the experiment results we find that the algorithm can work successfully in the Ad Hoc network to achieve the automatic choice of master node and meet the specific requirements for military purposes.