Suhua Tang

Fine-Grained Integration of Priority Control and Relay Selection for Fast and Reliable Inter-vehicle Communication

Inter-vehicle communication has two important controls: (i) prioritized transmission control ensuring that information with high priority is disseminated quickly and reliably, which typically relies on the setting of both Arbitration Inter-frame Space (AIFS) and backoff time in the Enhanced Distributed Channel Access (EDCA) mechanism of the MAC layer, and (ii) relay-vehicle selection for disseminating information efficiently, which is usually implemented in the upper layer. Previous efforts have separately designed and evaluated these controls, but a simple combination cannot achieve the full merits of both controls. In this paper, we propose a fine-grained integration of prioritized transmission control and relay selection by separately using the two components of the EDCA mechanism. (a) Prioritized transmission control is realized by properly setting AIFS for each priority. (b) Potential relay vehicles are explicitly ordered based on their progresses of wireless signal from the transmitting vehicle, and vehicles with high orders are selected as relay vehicles preferentially with a small backoff time. In addition, packet aggregation is used to improve the reachability of packets with low priority. Simulation evaluations confirm that the reachability of information with high priority is improved by up to 53% compared with other integration methods, and the delay is suppressed to be less than 400 ms.