  Vehicle-to-Everything communications (V2X) are becoming increasingly popular
as a solution for safer roads and better traffic management. One of the
essential protocols in V2X is the Dedicated Short Range Communication (DSRC)
protocol suite. DSRC includes the IEEE 802.11p protocol that operates at the
medium access control (MAC) and physical (PHY) layers. Upon collision, the IEEE
802.11p MAC layer applies a carrier sense multiple access/collision avoidance
(CSMA/CA) mechanism that randomly selects a backoff time to re-check the
channel activity and then retransmit. However, the random selection of the
backoff time may lead to further packet collisions that decrease the
utilization of the communication channel, which suffers from a limited
bandwidth in the first place. This paper proposes a fuzzy model based on
rational decision-making, which we call F-802.11p, to improve the IEEE 802.11p
protocol backoff time selection by limiting the IEEE 802.11p beacon messages to
better use of the available bandwidth. A simulation study presents the
evaluation of our work compared to IEEE 802.11p. We deployed the simulation
software in two scenarios: the Veins Framework map and the map of New
Administrative Cairo in Egypt. We base our comparison on slots backoff, times
into backoff, PHY busy time, MAC busy time, total lost packets, and
generated/received beacon messages. Simulation results show that both protocols
have comparable results in slots backoff, times into back off, and the
generated beacon messages. At the same time, our F-802.11p significantly
outperforms the IEEE 802.11p in PHY busy time, MAC busy time, total lost
packets, and the received beacon messages in both scenarios.
