ABSTRACT
Safety on roads for running vehicles as well as pedestrians is indispensable as well as a challenging aspect of Intelligent Transportation Systems (ITS). Owing to the prominent aspects of vehicular communication such as large range of variation in speed, dynamic vehicular density, intermittent failure to communication link and geographically constrained topology, data transfer becomes challenging. As a prerequisite to an efficient data communication system, vehicular network is expected to have such medium access control (MAC) protocols that can ensure reliable data dissemination particularly for safety-related services. In this article, a time division multiple access (TDMA) based MAC protocol is proposed that ensures fast and reliable data delivery in vehicular environment. The protocol integrates TDMA channelization technique and distributed coordination function mechanism to minimize packet collisions. It prioritizes safety messages by providing them immediate channel access over non-safety messages which are comparatively more delay-tolerant. Apart from that, the proposed channel access scheme enhances the existing IEEE standards in terms of multichannel coordination as well as MAC and PHY layer parameters. Results have been deduced using MATLAB and are in true conformity with the simulations performed. They demonstrate the utility and efficiency of the proposed scheme with improved parametric performance.
