Performance Evaluation of Joint Placement and Sleep Scheduling of Grid-Connected Solar Powered Road Side Units in Vehicular Networks

Ensuring ubiquitous connectivity in vehicular ad hoc networks (VANETs) has gained enormous importance in the research community. In this direction, placing a large number of road side units (RSUs) in the scenario has emerged as a solution. Although placing more RSUs leads to high coverage, it also leads to high deployment cost, operational cost, and total energy consumed. While optimal RSU placement helps to reduce cost, efficient sleep scheduling helps to reduce energy consumption at RSUs. In order to achieve both the benefits, for the first time, we propose joint placement and sleep scheduling of RSUs in a VANET environment. We perform a detailed analysis of the probability of successful packet delivery and expected vehicle-to-RSU delay for a packet by considering the presence of hidden terminals and retransmissions, and by modeling the buffer of a vehicle as an M/M/1 queue. We also formulate an optimization problem which captures the behavior of a realistic scenario and propose an energy efficient candidate location selection algorithm to jointly perform placement and sleep scheduling of grid-connected solar powered RSUs. Our simulation results show that the proposed approach performs better than the uniform placement strategy with and without sleep scheduling of RSUs and exhaustive search without sleep scheduling of RSUs. Also, the results obtained are close to the best case-exhaustive search with sleep scheduling of RSUs. Our analytical results are in good agreement with the simulation results.