Energy-Efficient Deployment of UAV in V2X Network Considering Latency and Backhaul Issues

Unmanned aerial vehicles (UAV) take place in the communication field more and more. Since the energy efficiency will be one of the most important issues in regard to smart city applications, energy-efficient deployment of the UAVs becomes a critical topic. Besides, V2X communication stands out in smart city applications and has its own unique problems such as latency. In this paper, we have investigated the energy-efficient deployment problem of UAV as flying roadside unit (RSU) with considering latency of vehicular users (VUs) and backhaul link capacity constraints while making power control of VUs as well. First, we proposed a junction scenario that a UAV is integrated as RSU to provide V2I links in a region while connecting the core network with a backhaul link. Then, when the number of vehicular users is given, we propose a communication problem that aims to minimize the total power consumption including both hovering and communicating powers. In our scenario, the probability of that the latency of the vehicular users is greater than a given value is kept below a certain violation probability. In the numerical results, it is stated that communication packet size is an essential parameter for the latency constraint in the network configurations. It is also observed that as the delay constraint tightens and the average packet size increases, the sum of the data rates of VUs converges to the backhaul link capacity. At the end of the paper, results for the proposed communication problem are provided.