Hazim M. Shakhatreh

Path loss is a significant component of wireless communication channel design and analysis and reflects the reduction in a transmitted signal’s power density. Due to the differences in the propagation conditions, wireless aerial channels’ features differ from those of terrestrial wireless channels; therefore, unmanned aerial vehicle path loss models are often different from conventional terrestrial wireless channel path loss models. A mathematical propagation model is proposed in this paper to estimate the Ground-to-Air path loss between a wireless device and a low-altitude platform using the frequency bands of the millimeter wave. The suggested model of Ground-to-Air path loss will assist academic researchers in formulating several vital problems.

In the last few years, the use of drones is increasing day by day in wireless networks and the applications of them are rapidly increased on different sides. Now, we can use the drone as an aerial base station (BS) to support cellular networks in emergency cases and in natural disasters. To take the advantage of both drones and fifth-generation (5G) and link between their features, we study an aerial BS considering millimeter waves (mm-waves). In this paper, we optimize the 3D placements for multiple unmanned aerial vehicles (UAVs) in an mm-wave network to achieve maximum time durations of the uplink transmission. First, we present a formulation for the placement problem, where we aim to allocate 3D locations for multiple UAVs to achieve the maximum sum of time durations of uplink transmissions. We propose an efficient algorithm to find the placements of UAVs. We propose an algorithm that starts by grouping the wireless devices into a number of clusters, and each cluster is served by a single UAV. After the clustering process, it applies the gradient projection-based algorithm (GP) or particle swarm optimization (PSO) in each cluster. In the results section, our proposed approach and the center projection algorithm will be compared to prove the efficiency of our approach.

Path loss is a significant component of wireless communication channel design and analysis and reflects the reduction in a transmitted signal’s power density. Due to the differences in the propagation conditions, wireless aerial channels’ features differ from those of terrestrial wireless channels; therefore, unmanned aerial vehicle path loss models are often different from conventional terrestrial wireless channel path loss models. A mathematical propagation model is proposed in this paper to estimate the Ground-to-Air path loss between a wireless device and a low-altitude platform using the frequency bands of the millimeter wave. The suggested model of Ground-to-Air path loss will assist academic researchers in formulating several vital problems.

The use of unmanned aerial vehicles (UAVs) is growing rapidly across many civil application domains, including providing wireless coverage. Most studies on UAV-based wireless coverage typically consider downlink scenarios from an aerial base station to ground users. The uplink scenario in which ground wireless devices transmit data to an aerial base station is only considered by few studies. However, the frequency bands that are used in these studies are not Millimeter Wave frequency bands, and this limits the applicability of these applications when one needs to consider 5G networks. In this paper, we are motivated to explore if the placement of UAV can enhance the time durations of uplink transmissions of wireless devices in Millimeter Wave UAV networks. First, we present a realistic Millimeter Wave path loss model and describe the tradeoff introduced by this model. Then, we study the problem of optimal UAV placement, where the objective is to determine the placement of a single UAV such that the sum of time durations of uplink transmissions is maximized. To this end, an algorithm to find the optimal UAV location is proposed. Simulation results are presented to validate the effectiveness of the proposed algorithm.

Unmanned aerial vehicles (UAVs) can be used as aerial wireless base stations when cellular networks go down. Prior studies on UAV-based wireless coverage typically consider outdoor scenarios, where a UAV and wireless devices are outdoor. In this paper, the problem of UAV placement is studied, where the goal is to find the optimum location of a single UAV that prolongs the lifetime of indoor wireless devices. First, a realistic Indoor-Outdoor path loss model is presented and the tradeoff introduced by this model is described. Then, the problem of UAV placement is formulated, where the goal is to find the optimum UAV location that prolongs the lifetime of indoor wireless devices. It can be proven that the constraint sets of the problem can be represented by a convex set in terms of three variables. To this end, an algorithm to find the optimum UAV location is proposed. Simulation results are presented to validate the effectiveness of the proposed algorithm.