The potential of transmit data rate control for channel congestion mitigation in VANET

Vehicular ad hoc networks (VANETs) promise to increase road safety, enhance road transportation efficiency and offer new communication-based services to road users. However, VANETs based on the European and American standards suffer from limited scalability due to poor robustness to radio channel congestion. At present, most works on congestion mitigation are based on transmit power control, while alternative approaches such as transmit data rate control are less popular. In this paper, transmit power control and transmit data rate control are compared, showing that the latter outperforms the former in a number of test scenarios, and particularly when channel congestion concerns a localized cluster of vehicles. The analysis is focused on the tradeoff between channel congestion mitigation and vehicles broadcast performance. Moreover, this work considers the decisive influence of congestion spatial distribution on the effectiveness of the compared approaches.