MULTIHOP R-ALOHA FOR INTERVEHICLE COMMUNICATIONS AT MILLIMETER WAVES

With reference to road transport information (RTI) applications, such as cooperative driving, short-range intervehicle communications in a h ighway environment are investigated in this paper, The research in thi s field indicates the suitability of the 60-64-GHz band. Due to the di stributed nature of the intervehicle communication system, an R-ALOHA protocol is considered; multihop (MH) and single-hop (SH) strategies a re compared, Network performance is assessed by considering the joint impact of random access, interference, thermal noise, propagation, and packet capture effect. Several figures of merit are analyzed and disc ussed: packet success probability (PSP), system stabilization time (SS T), first success time (FST), and deadline failure probability (DFP), Network performance is evaluated either by an analytical approach or b y a software tool able to simulate a one-lane highway scenario, Both s teady-state and transition situations are considered. System performan ce in terms of PSP (in the presence of two-ray Rice fading, noise, and interference with antenna diversity and selection combining) is analy tically evaluated to validate the simulation tool and to prove the sui tability of an MH network strategy, The simulation approach allows the evaluation of the impact of protocol parameters on network performanc e, with reference to nonsteady-state situations.