A Multi-Hop Broadcast Routing Based On Networt State Estimation For Vanet

In recent years, the traffic safety and efficiency has become a crucial social problem with the growing number of cars. The VANET (Vehicular Ad Hoc Network) has been proposed to enable the data transmission for the traffic information technique by applying the communication technique. It has attracted increasing academic and industry attention recently. Multi-hop broadcast which has been frequently used in VANET can distribute information such as emergency, road condition to vehicles or roadside infrastructures outwards the source center speedily.In traditional flood broadcast, every node will rebroadcast message once it receives a new one. Then large amount of redundancy data is generated which will consume the valuable network resource rapidly. As a result, the performance such as network delay and throughput drop seriously. So, in this paper, how to control the nodes rebroadcasting and provide real-time and reliable data dissemination in multi-hop broadcast will be mainly studied.A multi-hop broadcast routing that is based on network estimation called AS-FAMB (Adaptive Slot-time and Forwarding Acknowledgement based Multi-hop Broadcast) is proposed. Firstly, A candidate set based on vehicles position information is defined to limited nodes forwarding. And then an adaptive slot-time and a forwarding node selection mechanism based on short control packets are developed to further reduce the redundancy data and forwarding delay. Finally, an over time rebroadcasting scheme is carried out to guarantee the transmission reliability.In this paper, the network simulator NS2is used to implement and evaluate the AS-FAMB in different traffic density and network load. The results confirm that AS-FAMB mitigates the broadcast storm significantly and it also performs well in the real time and reliability of data transmission.