Exploiting Large Vehicles with High Antenna for Efficient Relay in Inter-Vehicle Communication

Inter-vehicle communication (IVC) helps to prevent vehicle accidents by disseminating vehicle position and speed information, and road/traffic information among vehicles. Relay vehicle selection control (for disseminating road/traffic information in a wide range) and prioritized transmission control (for disseminating fast and reliably urgent information such as sudden brake information) play important roles in IVC. Our previous work proposed to integrate the two control functions explicitly in the MAC (Media Access Control) layer. Relay vehicle selection control is realized by sorting vehicles in the descending order of their distances from the transmitting vehicle and on this basis a different waiting time is set to each vehicle via using CW (Contention Window) in the EDCA (Enhanced Distributed Channel Access) mechanism of wireless LANs. In this paper, we further consider the coexistence of ordinary and large vehicles. A large vehicle, with a high antenna and a long transmission distance, is more preferentially selected as relay by introducing a new metric-potential relay distance. Simulation results show that by preferentially selecting large vehicles as relay, the proposed method can improve the reachability by up to 10% and reduce the delay by 35% in the highway scenario, and can improve the reachability by up to 4% and reduce the delay by up to 13% in the urban scenario.