Network Coding Based Protocol For Data Transmission In Vehicle Ad-Hoc Networks

Network coding is a technique to improve the performance of network communication. It changes the traditional store-forward mode, using the new store-code-forward mode. This model, based on network flow theory, max-flow min-cut theorem, can achieve the maximum network throughput in theory, and thus can improve the performance of the whole network. Physical layer of wireless networks is broadcast in nature, which can be easily integrated with network coding. Network coding can also improve the reliability of wireless networks effectively. Therefore, network coding is promising in wireless networks.VANET (Vehicle Ad hoc NETwork) is a mobile ad-hoc networks consisting of road vehicles and roadside access points, is a way to achieve the communication between vehicles and the communication between the access points and vehicles. In this thesis, we design a network coding based protocol for data transmission in vehicle ad-hoc networks VNC (VANET Network Coding protocol). This protocol can improve the performance of data transmission in VANET. VNC protocol combines network coding technique and the characteristics of VANET, using a variety of optimizations to improve the performance and adaptability. VNC protocol draws on the ideas of opportunity routing and uses the method of APs multicasting. With the movement of vehicles the multicast list updates in order to improve the efficiency of data transmission. VNC protocol using limited broadcast mechanism, limits the range of data broadcasting between the two access points, to reduce the protocol overhead. VNC uses progressive random linear network coding to increase decoding ratio at destination nodes.We implement VNC protocol in NS2 platform. Unicast and multicast traffic scenarios are designed to evaluate the performance of VNC protocol in terms of delivery ratio, average delay and protocol overhead, compared with the VFlood protocol without network coding. Simulation results show that VNC protocol effectively improves the performance of data transmission in VANET.