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While using UAVs in the Drone-Base Station scenario, we need to consider the network performance characterization, best method of 3D deployment of drones, allocation of both wireless as well as computational resources, optimization of flight time, and planning of UAV network. Operation in Drone-UE scenario should take into consideration issues like channel modeling, handover management, low latency control, interference management and 3D localization. To use UAVs for specific applications of wireless communication networks, factors like capability of UAV, flight constraints of UAV, energy constraints of UAV, the flying altitudes of UAV must be taken into account. Since UAV communication has distinctive channel characteristics of its own, accurate channel characterization is essential for optimum performance and efficient designing. The propagation characteristics of the highly dynamic UAV channels have not yet been properly explored, in terms of the spatial and temporal variations induced in the non-stationary channels of UAV networks. Designing of a generic channel model for UAV air to ground communications (A2G), demands for simulations and measurements to be carried out comprehensively in various environments, taking into consideration the altitudes at which the UAV is flying, it’s antenna movements, shadowing caused by UAV’s body, etc. Airframe shadowing caused due to structural design and maneuvering of small rotary UAVs is yet to be explored in detail, though preliminary studies were carried out by Sun et al. in 2017. Figure 2.1 depicts the design issues faced in the UAV-assisted communication networks.

The rest of the chapter discusses in detail the above mentioned design issues encountered in deployment of UAV-assisted communication networks, the solutions proposed till date and the open research areas that need to be worked upon for optimizing the performance of the UAV systems. Designing of UAV-assisted communication networks is a great challenge in itself.

Figure 2.1 Design issues of UAV-assisted communication networks.