Time Slot Evaluation Based on DCF Mechanism Under Urban Traffic Scenario in Vehicular Network

This paper is focusing on improving the Quality of Service (QoS) in Vehicular Ad-Hoc Network (VANET) under urban traffic scenarios through the utilization of the Distributed Coordination Function (DCF) mechanism at the Medium Access Control (MAC) layer. The primary purpose of VANET technology is to facilitate the real-time exchange of high-speed data information among vehicles using the On-Board Unit (OBU) and with roadside infrastructure using Roadside Unit (RSU). In vehicular networks, the IEEE 802.11p or Dedicated Short Range (DSRC) is used as a standard protocol based on DCF mechanisms with slot time being a significant factor for optimization. The slot time represents the duration of a time slot within which a vehicle can access the channel. It is influenced by the maximum range of the network and provides a crucial part in achieving efficient data transmission. This project investigates the impact of different slot time values between 10µs, 20µs and 50µs and implements routing protocols including Ad hoc On-Demand Distance Vector (AODV), Dynamic Source Routing (DSR) and Destination-Sequenced Distance Vector (DSDV) through simulation using Network Simulator 2 (NS-2), Java Open Street Map (JOSM), Simulation of Urban Mobility (SUMO) and Mobility Model Generator for Vehicular Network (MOVE). The results of the comparison provide insights into the effectiveness of different routing protocols and their suitability in achieving desired QoS levels under three slot time durations. The findings of this project contribute to the understanding of how slot time optimization and routing protocol selection can enhance the QoS in VANET, ultimately improving the efficiency and reliability of vehicular communication in urban environments. Our preliminary results indicate that the AODV protocol consistently outperforms DSR and DSDV in terms of throughput and packet delivery ratio across all tested slot time values, with the most significant improvements observed at the 20µs slot time.