Efficient Optimal Backhaulaware Placement of Multiple DroneCells Based on Genetic Algorithm * Dronecell is a promising solution for providing GSM3GLTE5G mobile networks to victims and rescue teams in disasteraffected areas. One of the challenges that dronecells are facing is the limitation of reliable backhaul links. In this paper, we study the optimal placement problem of a group of dronecells deployed in a disaster area with limited backhaul communication ranges, aims to maximize the number of served users. Two approaches, exhaustive search algorithm and a computationally efficient genetic algorithm are proposed, and the optimal 2D backhaulaware placements of multiple dronecells are found for each approach. We also introduce a restartstrategy to enhance searching efficiency and avoid local optimums for the proposed genetic algorithm. Simulations show that the proposed genetic algorithm can save the computing time up to 99.927% compared with the exhaustive search algorithm, and the restartstrategy helps the probability of finding the global optimum by the proposed genetic algorithm increased from 12% to 92%.

Aerial Access and Backhaul in mmWave B5G Systems: Performance Dynamics and Optimization The use of unmanned aerial vehicle (UAV) based communication in millimeterwave (mmWave) frequencies to provide ondemand radio access is a promising approach to improve capacity and coverage in beyond5G (B5G) systems. There are several design aspects to be addressed when optimizing for the deployment of such UAV base stations. As traffic demand of mobile users varies across time and space, dynamic algorithms that correspondingly adjust the UAV locations are essential to maximize performance. In addition to careful tracking of spatiotemporal usertraffic activity, such optimization needs to account for realistic backhaul constraints. In this work, we first review the latest 3GPP activities behind integrated access and backhaul system design, support for UAV base stations, and mmWave radio relaying functionality. We then compare static and mobile UAVbased communication options under practical assumptions on the mmWave system layout, mobility and clusterization of users, antenna array geometry, and dynamic backhauling. We demonstrate that leveraging the UAV mobility to serve moving users may improve the overall system performance even in the presence of backhaul capacity limitations.