On power adaptation schemes in aerial-terrestrial communications

This paper mainly studies the transmission capacity performance of an aerial-terrestrial communication system, in which an unmanned aerial vehicle (S) delivers information bits to a terrestrial receiver (D) by adaptively controlling its transmit power according to the instantaneous channel state information. In this work, three adaptive transmission schemes, i.e., optimal simultaneous power and rate adaptation, optimal rate adaptation with constant transmit power and truncated channel inversion with fixed rate, are considered at S. Closed-form expressions for the ergodic capacity (EC) under these adaptive transmission schemes are derived, while considering the randomness of the location of D. Furthermore, some insights are obtained by deriving asymptotic expressions for the EC. Finally, numerical results are proposed to compare the performance of these considered power adaption methods, as well as to confirm the accuracy of the proposed analytical models.