Uplink Resource Allocation in Cellular Networks with Energy-Constrained UAV Relay

Abstract

In this paper, we focus on a cellular network with a energy-constrained unmanned aerial vehicle (UAV), which serves as a relay for all the users to improve their uplink rates via cooperative communication. Uplink resource allocation in terms of power and time allocation among users is investigated to optimize the uplink sum-rate. By leveraging the local search strategy, the sum-rate optimization problem is decomposed into two subproblems, i.e., energy allocation and time allocation. We derived the optimal solution for both amplify-and-forward (AF) and decode- and-forward (DF) protocols with in-depth analysis. Numerical results show that path loss exponent has non- trivial impact on the sum-rate while higher energy replenishment rate of the UAV relay brings little performance gain. In addition, location of the UAV is also non-negligible and the cellular network can significantly benefit from proper deployment of the UAV relay.