A near collision free reservation based MAC protocol for VANETs

Compared with the CSMA based MAC protocols, the slotted reservation solutions could be more adaptable for VANETs. However, the high mobility and mobile hidden terminal (MHT) issues in vehicular environments cause a challenge of efficient and scalable slotted scheduling for TDMA MAC protocols. This paper proposes a novel near collision free reservation (CFR) MAC which is based on a recent VeMAC protocol to provide near collision free scheduling and address the mobile hidden terminal issue in VANETs. In former distributed TDMA MAC proposals like VeMAC, on the control channel of DSRC communication system, each vehicle randomly reserves dedicated time slots. However, the slot reservation of CFR MAC is more structural, based on the driving status and traffic flow of each vehicle. The performance of CFR MAC is verified via simulations and comparisons with IEEE 802.11p and VeMAC to demonstrate that superiority of CFR MAC.