On the Performance Enhancement of Vehicular Ad hoc Network for Transportation Cyber Physical Systems

Timely dissemination of safety related information in a Vehicular Ad-hoc Network (VANET) for transportation cyber physical systems (CPS) is always challenging because of delay constraint and data collision in the network. In this paper, we investigate an analytical approach for enhancing network performance through dynamic adaptation of transmit range/power and contention window for IEEE 802.11p based VANETs. The proposed model uses a Markov chain for transmission opportunities for messages using enhanced distributed channel access (EDCA) in VANET. The estimated local traffic density and data collision rate are used to adapt both transmission range and contention window of each message category on the fly in VANETs. Existing state-of-the-art work considers either adaptation of transmit power or contention window in VANET based on a single parameter which might not provide reliable communication for transportation CPS. In order to corroborate the mathematical analysis, we present numerical results obtained from Monte Carlo simulations. The proposed approach with dynamic adaptation of transmission range and contention window outperforms the existing approaches.