Based On The Location Of The On-board Self-organizing Network Communication Routing Protocol Research

Because of the restrictions of wired communication mode in the range of applications, wireless mobile communication was invented. In recent years, the rapid growth of wireless networks in support of mobility, coupled with the immediate problem of traffic informationization, require the research on Vehicular Ad Hoc Networks (VANET). VANET is a multi-hop wireless ad hoc network, which is able to establish a mobile communication network at any time in any place without any infrastructure. Each node in the network can move freely and have equal status. Through the applications of early warning, computer-aided driving, distributed traffic information publishing, information services, entertainment services and so forth, VANET implements "the smooth flow of goods, the convenient travel of people". However, high mobility of vehicular nodes makes high dynamics of topologic structure for vehicular network, and finally leads to frequently disconnection of multi-hop route in VANET. All of them bring great challenges to reliability of routing algorithm and quality of data transmission. This paper analyzes the previous works in related fields at home and abroad, makes comparison among the existing VANET routing protocols, and improves position-based routing protocol——GPSR. The main work is as follows:To solve the problem caused by high mobility of nodes, this paper combines with the ability of greedy routing and ant colony algorithm in finding optimum solution, proposes an algorithm named AGA, which improves GPSR based on ant colony algorithm. In most cases, GPSR can find optimum solution, but in a few cases, the obtained path is neither optimal, nor suboptimal, but a very long path. When greedy routing is failed, AGA passes the void area by probability selecting the next hop based on ant colony algorithm, and updates the position of destination node in data packet header during transmission. AGA implements data offloading and prevents network jam. This algorithm selects the next hop by prior-computing node’s position, therefore, is better able to adapt to the high-speed environment.To avoid the routing void in middle or low speed environment, this paper proposes an algorithm (P-GPSR) which improves GPSR based on predecessor node forwarding. In order to resolve the long path problem in GPSR, it is necessary to avoid routing void. Because the destination nodes broadcast query message periodically, each node records the predecessor node of the query message as the forwarding next hop of data packet, thereby avoiding routing void and saving the data packet transfer delay.This paper uses network simulation platform NS-2to simulate these protocols. To avoid human disturbance, all of the experimental scenes are from traffic simulator VanetMobiSim. Based on the comparison, this paper makes a comparison between the protocol proposed in this paper and the existing routing protocol, by rates of successful packet deliveries, packet loss ratio, mean end-to-end hops and packet delay. The result of the simulation reveals that AGA is able to achieve a more stable and reliable transmission of data packets, and P-GPSR has great performance in avoiding routing holes.