Completed Tasks Number Maximization in UAV-Assisted Mobile Relay Communication System

Abstract

Unmanned aerial vehicle (UAV) with high flexibility, ease of deployment, and low cost has been widely applied to our daily life. In this paper, an UAV-assisted mobile relay communication system is considered, in which one UAV and one access point (AP) jointly provide computing resources for dense user equipment (UE) on the ground. We aim to maximize the number of tasks completed on the UAV and AP by optimizing the local computing frequency, offloading ratio, offloading power, computing frequency of the AP, computing frequency of the UAV, relaying power of the UAV, and relaying ratio of the UAV. Because the formulated problem is a mixed-integer nonlinear programming (MINP) problem that is very difficult to solve directly, we convert it into the problem of minimizing the computing frequency allocated by the UAV and AP to each UE. Then block coordinate descent (BCD) method is adopted to solve the converted problem. An optimal partial offloading and relaying scheme (POARS) is proposed to obtain the maximal number of completed tasks. Finally, simulation results show that POARS has a better performance than other schemes.