Performance analysis of cooperative ADHOC MAC for vehicular networks

The paradigm of vehicular ad-hoc networks (VANETs) emerges as a promising approach to provide road safety, vehicle traffic management, and infotainment applications. Thus, it is important to develop a VANET medium access control (MAC) protocol that provides an efficient and reliable delivery of packets for diverse applications. Cooperative communication, on the other hand, can enhance the reliability of communication links in VANETs, thus mitigating wireless channel impairments due to a poor channel condition. Recently, a cooperative scheme for MAC in VANETs based on time-division multiple access, referred to as Cooperative ADHOC MAC (CAH-MAC), has been proposed [1]. CAH-MAC is an efficient protocol capable of increasing the network throughput by reducing the wastage of time slots. In CAH-MAC, neighboring nodes cooperate by utilizing the unreserved time slots, for retransmission of a packet which failed to reach its target receiver due to a poor channel condition. In this paper, we study the reliability of CAH-MAC in terms of packet transmission delay (PTD) and packet dropping rate (PDR). Through mathematical analysis and computer simulation, we show that CAH-MAC provides reliable communication by decreasing the PTD and PDR as compared with existing approaches.