A Review on Congestion Control in MAC Layer of VANET

Abstract: Vehicular Ad hoc Networks (VANET) play an important role in future car-to-car communication systems and related applications like Self-Organizing Traffic Information Systems (SOTIS), which are based on broadcast/geocast transmission schemes. Congestion control for VANETs has not been studied thoroughly so far - but this feature will be extremely necessary for VANET applications and network performance. Due to the high mobility and the resulting highly dynamic network topology, congestion control will need to be performed in a decentralized and self-organized way, locally in each VANET node. This paper presents a novel concept for utility-based congestion control and packet forwarding in VANETs. The control algorithm uses an application-specific utility function and encodes the quantitative utility information in each transmitted data packet in a transparent way for all users within a local environment. A decentralized algorithm then calculates the "average utility value" of each individual node based on the utility of its data packets and assigns a share of the available data rate proportional to the relative priority.

Keywords: VANET, MANET, Congestion Control.