Ultra-Reliable and Low-Latency UAV Communications in High-Mobility Environments

Ultra-reliable and low-latency communications (URLLC) are one of main scenarios of the fifth-generation (5G) and beyond-5G wireless networks, where most existing work concentrated on the tailored resource allocation on the premise of known channel state information (CSI) to meet its strict requirements. However, sometimes due to the high mobility of transceivers, the instantaneous CSI is highly time-varying such that we cannot capture it in a timely manner. Motivated by this background, we in this paper investigate the provisioning of URLLC over unmanned-aerial-vehicle (UAV) networks in high-mobility environments, considering that only the distribution of CSI is available at the transmitter. The short-packet transmission is assumed to guarantee the low-latency requirement. The influences of channel outage probability and block error rate of short-packet transmissions are analyzed to evaluate and guarantee transmission reliability. Next, we delve into the transmit power minimization problem by firstly relaxing it to be convex and then devising the corresponding optimal solution with convex optimization techniques. The numerical results verify the superiority of our proposal.