Cross-layer architecture for congestion control in Vehicular Ad-hoc Networks

Vehicular Ad-hoc Networks (VANETs) are special kind of Mobile Ad-hoc Networks (MANETs). The distinctive characteristics of the VANETs include high speed of vehicular nodes and high variability in node density. Congestion detection and control protocols have been proved to be an efficient method for improving network performance and are well studied for the MANET environment. However, they often result in sub-optimal network performance for the vehicular network environment due to the specialized characteristics of VANET. In this paper we present an adaptive and distributed cross-layer congestion detection and control protocol for the VANET environment. During the congestion detection phase, information from each layer of the network protocol stack is combined and mapped on to congestion levels. In the subsequent congestion control phase parameters like contention window, transmission rate and transmit power are jointly adjusted to improve on the network performance. The effectiveness of the proposed model is evaluated through mathematical analysis and simulation-based studies.