The Research And Simulation Of Routing Protocols In Ad Hoc Networks

Ad Hoc network composed of mobile nodes with wireless communication device are typically characterized by their multi-hop, self-organized and un-center. With its highly flexibility, Ad Hoc network will be widely used in the fields of military, civil and various environments which the fixed communication infrastructure are difficult to set up. However, the traditional internet routing protocol can not meet the demand of Ad Hoc network because the topology of which frequently changes. So the routing protocols are always an important research field of Ad Hoc network.This paper firstly introduces the conception & characteristics of Ad Hoc network, then analyses the route technology. Detailed discussion of current typical routing protocols is made from the follow aspects, route discovering, route maintaining and so on. Simulation of two typical routing protocols, OLSR and AODV is done in NS2. Average Packet Delivery Fraction, Average End-to-End Delay and routing Load three main parameters are selected to compare the performance of the two route protocols for difficult scene. Simulation results show that OLSR is applied in large scale, high node density and slowly speed Ad Hoc network. AODV is applied in small scale, high speed Ad Hoc network.Secondly,A new QoS routing protocol based on DSR named QOS-DSR. QOS-DSR optimized route setup process and provided bandwidth computation and judgment mechanism. It can select shortest path with end-to-end bandwidth demand satisfied for data flows, and reduce network overhead in flooding process.Finally, QOS-DSR was simulated in NS2. The result shows that the QOS-DSR performs better than DSR in drop ratio, the overhead of routing protocol is acceptably, QOS-DSR guarantees the QoS, such as bandwidth. So it comes to the conclusion that QOS-DSR is an efficient QoS routing protocol. In the end, this paper discusses possible future directions in the QoS routing research area.