On the ergodic sum rate for multisource multidestination unmanned aerial vehicle relaying

Unmanned aerial vehicle (UAV) relay system has received significant attention in future wireless communications. In this article, the ergodic sum rate of a multisource multidestination UAV relaying is investigated. Here, an UAV with multiple antennas is deployed as an aerial relay using threshold‐based decode‐and‐forward protocol to assist signal transmission from multiple sources to their intended destinations simultaneously. By considering the effect of path loss, we first obtain the output signal‐to‐interference‐plus‐noise ratio expression for the considered system. Then, we propose a statistical channel state information based beamforming (SCSI‐BF) scheme to maximize the system ergodic sum rate, where both of the uplink and downlink channels are subject to correlated Rayleigh fading. Furthermore, we derive the analytical expression for the ergodic sum rate of the considered system with the SCSI‐BF scheme. Finally, numerical results are given to demonstrate the superiority of the SCSI‐BF scheme and the validity of the theoretical analysis, and show the impact of various parameters on the system performance. A multisource multidestination UAV relaying is investigated. And a statistical channel state information based beamforming scheme ia proposed to improve the performance of the considered system. Finally, the analytical expression for the ergodic sum rate is derived to measure the performance of the considered system.