CADMA: collision-avoidance directional medium access for vehicular ad hoc networks

Abstract

Quick and accurate message transmission is an important research topic for vehicular ad hoc networks (VANET). Most studies assume that the periodic broadcast of beacon frames between vehicles increases the safety of the driver. In particular, there has been a lot of research into broadcasting based on carrier sense multiple access with collision avoidance (CSMA/CA) algorithms for medium access. However, the CSMA/CA algorithm is not an optimum technique for the VANET system, due to the transfer delay that occurs in inducing frequent collisions on transmission signals. In this paper, we propose a collisionavoidance directional medium access (CADMA) protocol and infrastructure-utilized clustering method for VANET to support reliable data transfer. In the proposed scheme, the CADMA protocol uses non-competitive transmission methods and cluster heads (CHs) to manage access by allocating the nodes resources. In addition, the roadside unit (RSU) helps with the clustering process. The simulation results indicate that the CADMA can reduce transmission delays and the collision rate of the broadcasting signal, and have shown that the CADMA can be effectively utilized for the VANET systems.

Review of MAC Protocols for Vehicular Ad Hoc Networks

“…Collision-avoidance directional medium access (CADMA) uses a cluster-based polling mechanism [ 74 ]. The cluster size is set to the maximum communication distance between two vehicles, allowing direct communication between them.…”

Communication delay guarantee for IEEE 802.11p/wave Vehicle networks with RSU control

“…The CADMA (collision-avoidance directional medium access for vehicular ad hoc networks) [2] uses clustering and polling technique. The RSU is responsible of getting information from vehicles, creating clusters and selecting cluster heads.…”

“…They are classified in two types: (1) TDMA based access and (2) polling access [2,5,12]. In The first kind, slot times are assigned to different OBUs to have separate access without transmission interferences (or collisions).…”