Capacity Analysis of UAV-to-Ground Channels With Shadowing: Power Adaptation Schemes and Effective Capacity

In this paper, an unmanned aerial vehicle (UAV), acting as a transmitter, employs different power adaptation strategies in order to enhance the ergodic capacity of the wireless channel between it and a receiver on the ground. We present the derivation of closed-form expressions for the channel capacity of the recently developed UAV-to-ground fading channels under different power adaptation strategies. The power adaptation strategies considered in this paper are optimal rate adaptation with fixed power (ORA), optimal power and rate adaptation (OPRA), channel inversion with fixed rate (CIFR), and truncated channel inversion with fixed rate (TIFR). In addition to ergodic capacity analysis, precise analytical formulas for the effective capacity of the UAV-to-ground fading channels are derived. Additionally, all of these closed-form expressions are verified by comparing them with numerical results obtained through Monte Carlo simulations.