Research Article Adaptive Beaconing in Mobility Aware Clustering Based MAC Protocol for Safety Message Dissemination in VANET Nishu Gupta, Arun Prakash, and Rajeev Tripathi Department of Electronics and Communication Engineering, Motilal Nehru National Institute of Technology Allahabad, Allahabad, India Correspondence should be addressed to Nishu Gupta; rel0513@mnnit.ac.in Received 27 July 2016; Accepted 16 October 2016; Published 11 January 2017 Academic Editor: Oscar Esparza Copyright © 2017 Nishu Gupta et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Majority of research contributions in wireless access in vehicular environment (WAVE)/IEEE 802.11p standard focus on life critical safety-related applications. Tese applications require regular status update of vehicle’s position referred to as beaconing. Periodic beaconing in vehicle to vehicle communication leads to severe network congestion in the communication channel. Te condition worsens under high vehicular density where it impacts reliability and upper bound latency of safety messages. In this paper, WAVE compliant enhancement to the existing IEEE 802.11p protocol is presented which targets prioritized delivery of safety messages while simultaneously provisioning the dissemination of nonsafety messages. Proposed scheme relies on dynamic generation of beacons to mitigate channel congestion and inefcient bandwidth utilization by reducing transmission frequency of beacons. Trough the use of clustering mechanism, diferent beaconing frequencies and diferent data transmission rates are assigned to prioritize vehicular mobility. Trough extensive simulation results, the performance of the proposed approach is evaluated in terms of a wide range of quality of service (QoS) parameters for two diferent transmission ranges. Results show that the proposed protocol provides signifcant enhancement and stability of the clustered topology in vehicular ad hoc network over existing standard and other protocols with similar applications. 1. Introduction Vehicular ad hoc network (VANET) in recent years has emerged as a promising wireless network technology for academia, research community, and industry to support a wide range of applications ranging from travel safety to trafc management and navitainment (navigation and entertain- ment). VANET adopts dedicated short-range communica- tion (DSRC) technology which is based on short-range wire- less communication under the process of standardization as the wireless access in vehicular environment (WAVE)/IEEE 802.11p standard [1]. VANET facilitates wireless communica- tion among vehicles (vehicle-to-vehicle or V2V communica- tion) and between vehicles and road side units (vehicle-to- infrastructure or V2I Communication). V2V communication forms a basis for decentralized active safety applications that are expected to reduce accidents and their severity [2]. Safety- related applications emphasize avoiding the risk of road acci- dents. Intersection collision warning, lane merge warning, lane change alert, precrash sensing, trafc violation alert, and road condition alert are some examples. Tese applications have real-time constraints, timeliness being the prominent one [3]. However, the inherent features of vehicular net- working such as high speed, intermittent connectivity, and frequent topological changes lead to special issues and chal- lenges in the network design, especially at the medium access control (MAC) layer. One such issue in VANET that has yet not been addressed convincingly is how the nodes should share the radio resources in order to ensure optimum quality of service (QoS) especially for safety assurance. Te safety and nonsafety message requirements are accomplished by exchanging short messages called beacons. Message dissem- ination through beacons in VANET is termed as beaconing. Information inside a beacon may include vehicle’s location, speed, moving direction, and other driving/topographical information [4]. Since all vehicles access the same control channel, the beaconing load may eventually saturate the capacity of the Hindawi Wireless Communications and Mobile Computing Volume 2017, Article ID 1246172, 15 pages https://doi.org/10.1155/2017/1246172