An Empirical study on MAC layer in IEEE 802.11p/WAVE based Vehicular Ad hoc Networks

Abstract

Intelligent Transportation Systems use Vehicular Ad-hoc Networks to improve road safety. Dedicated Short Range Communications (DSRC or IEEE 802.11p) and Wireless Access in Vehicular Environments (WAVE or IEEE 1609 protocol suite) are the two important standards that govern communication in VANETs. However, DSRC based VANETs cannot guarantee to achieve the Quality of Service (QoS) requirements like reliability and latency under high vehicle density scenario due to network congestion. This paper studies the congestion behavior of IEEE802.11p/1609.4 based Medium Access Control by varying vehicle density in urban and highway conditions. Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is the default medium access mechanism in WAVE MAC. The metrics chosen for evaluating the performance of CSMA/CA are the average end-to-end delay, average throughput, packet delivery ratio, packet loss ratio and the number of packets lost. The simulation is carried out for both urban and highway scenario under varying vehicle density and communication load. The Simulation is performed using Omnet++ and SUMO based veins framework. The simulation results show that under high vehicle density and high communication load, CSMA/CA fails to meet the required QoS.