A Low-Latency and Energy-Efficient Multimetric Routing Protocol Based on Network Connectivity in VANET Communication

Intelligent transportation systems (ITSs) are important applications of 5G mobile communication technology. Vehicular ad hoc networks (VANETs) are key part of intelligent transportation systems. Although 5G technology and infrastructure can significantly promote the development of VANETs, in some scenarios, for example, if 5G service is not available or the vehicle speed is too fast, device to device (D2D) will be an important means of communication. Therefore, combining 5G and D2D VANET communication is crucial to provide better connectivity. However, due to high-speed mobility, uneven distribution, and unpredictable vehicle behavior, the VANET network topology changes rapidly, and network connectivity is unstable. This phenomenon represent a considerable challenge to the routing protocol; at the same time, the continuous establishment of new routes needs to send a large number of routing requests (RREQ) and routing reply (RREP) packets, and it therefore consumes considerable energy. How to choose a more stable route is the key to implementing the routing protocol. In this paper, we take the most representative features of vehicles and roadways into consideration and based on the hypothesis of uneven vehicle distribution, we use a nonhomogeneous Poisson process to analyze the network connectivity and take the network connectivity as one of the routing decision metrics. Therefore, using fuzzy logic to make routing decisions under multiple selection criteria, we developed a new routing protocol named LENC (low-latency and energy-efficient routing based on network connectivity). Simulations have been performed comparing classical AODV and LENC. The results indicate that LENC represents a great improvement in routing stability and is superior to AODV in several aspects.