Bus Assisted Connectionless Routing Protocol for Metropolitan VANET

The rapid development of the wireless communications lets more and more people are used to access network services via various wireless technologies. Users expect the ubiquitous network environments to acquire information they needed anytime and anywhere. How to provide an efficient routing protocol is one of major challenges in VANETs to improve the performance in terms of packet delivery ratio, end-to-end delay with less control overheads. In this paper, we propose two schemes: (1) The footmark leaving scheme. It can pursue the target vehicle automatically in compliance with its moving trajectory without route recalculation and the aid of GPS during transmission. It only maintains a table of passed vehicles in each road segment to efficiently seek out target vehicles. (2) The bus-assisted transmission protocol. By benefiting from the predictability and regularity of buses, packets can be transmitted by switching between common vehicles and buses so that routes would be more feasible and scalable. It can greatly improve the reliability of transmitting packets in VANET.