Real time and Efficient Unicast Routing Protocols for Vehicular Ad Hoc Network: A Survey and Recommendations for efficiency enhancement

Vehicular Ad Hoc Network (VANET) is a new class of wireless technologies that integrates ad hoc network, wireless local area network and mobile technologies to achieve intelligent transportation system and improve road traffic safety. But there are numerous challenges to deal with. VANET has large-scale size, hybrid network architecture, frequent connection breaks, swift topology changes, characteristics of node movements, and new application platforms. Therefore, developing highly efficient and real time unicast routing protocols for VANETs is a difficult task. In this paper, we study and analyze some state-of-the-art unicast routing protocols developed to achieve efficiency in real-time scenario and describe their advantages and disadvantages. We further make some recommendations for potential improvements in terms of delay, throughput and overall efficiency.