Performance evaluation of IEEE 802.11p by varying data rate and node density in vehicular ad hoc network

Vehicular environments impose stringent requirements on wireless communication systems due to their inherent feature of being highly dynamic in nature. Vehicular applications cannot tolerate long access delays to disseminate their messages in order to communicate with other neighboring nodes, or with the infrastructure units. Moreover, from safety point of view, these applications demand high reliability with real-time data dissemination. Time bound delivery and inevitable channel access becomes a significant criterion to meet real-time delivery requirements; that too when it is known that the medium access technique employed in IEEE 802.11p, CSMA/CA, is unsuitable for critical communication scenarios. There exists various channel access schemes that envisage meeting stringent requirements of vehicular applications to some extent. However, to evaluate the strength and weaknesses of each technology on the basis of different performance metrics is an equally challenging task. In this paper we evaluate the performance of the IEEE 802.11p standard for varying node density and data transfer rate by means of simulations using NS-3. Simulations are performed for urban scenario in vehicle-to-vehicle mode. Results are presented and comparisons are made to evaluate various QoS parameters such as, throughput, end-to-end delay, packet loss ratio and packet delivery ratio. Significant observations have been made which would serve as an input to enhance further research in this field.