Joint Transmit Power and Placement Optimization for URLLC-enabled UAV Relay Systems

TL;DR

This paper develops algorithms to optimize UAV placement and power for ultra-reliable, low-latency relay communication, improving performance in both free-space and 3D channel models.

Contribution

It introduces joint optimization methods for UAV location and power that enhance URLLC relay systems, including low-complexity algorithms and a globally optimal solution for high SNR scenarios.

Findings

Proposed algorithms outperform baseline methods in simulations.

Joint optimization reduces decoding error probability under latency constraints.

Algorithms are effective for both free-space and 3D channel models.

Abstract

This letter considers an unmanned aerial vehicle (UAV)-enabled relay communication system for delivering latency-critical messages with ultra-high reliability, where the relay is operating under amplifier-and-forward (AF) mode. We aim to jointly optimize the UAV location and power to minimize decoding error probability while guaranteeing the latency constraints. Both the free-space channel model and three-dimensional (3-D) channel model are considered. For the first model, we propose a low-complexity iterative algorithm to solve the problem, while globally optimal solution is derived for the case when the signal-to-noise ratio (SNR) is extremely high. For the second model, we also propose a low-complexity iterative algorithm to solve the problem. Simulation results confirm the performance advantages of our proposed algorithms.