Optimizing Vehicular Safety Message Communications by Adopting Transmission Probability With CW Size

Vehicular ad hoc networks (VANETs) will have noteworthy breakthroughs with the upcoming 5G and 6G technologies. In VANETs, the performance changes with traffic, contention window (CW) size, and vehicle velocity. Since the velocity and number of vehicles are not controllable, CW size will be optimized to maximize performance. In this paper, performance is optimized for highly important safety messages (sm) in VANETs by optimizing CW size with respect to number of vehicles and vehicle velocity. If any of these parameters (velocity and/or number of vehicles) changes, CW size will be dynamically adjusted to keep performance at optimum level. The comparison between IEEE 802.11 and IEEE 802.11p for sm in VANETs is presented where performance is maximized for both IEEE 802.11 and IEEE 802.11p. Markov chain based analytical model is developed and optimum expressions are derived. SUMO is used to build the microscopic mobility model. Monte Carlo simulation results are provided which verify analytical study and demonstrate that the performance is maximized regardless of parameters variation.