Channel Modeling and Performance Analysis of UAV-Enabled Communications With UAV Wobble

Because of the influence of wind, unmanned aerial vehicles (UAVs) inevitably experience different degrees of wobble while flying. Considering the impact of effective apertures (EA) on the performance of array antennas, this letter proposes a channel model for UAV-enabled communication systems, which incorporates the UAV's pitch and yaw, as well as the randomly varying EA caused by the UAV's wobble and flight posture. The general expression for the average signal-to-noise ratio (ASNR) is derived based on this model. From this general expression, we derive a closed-form expression for the case when the receiver is located directly below the hovering UAV. In deriving this closed-form expression, a method for approximating the general expression using a finite power series is proposed. The numerical results show that even slight wobble of the UAV can severely degrade the performance of the communication system. Moreover, owing to the wobble, increasing the number of antenna elements does not narrow the beamwidth and can't lead to a significant improvement in ASNR. Furthermore, we find that in a UAV-enabled communication system, neglecting the EA also results in a severe overestimation of the ASNR.