Simultaneous Wireless Information and Power Transfer for Multiuser UAV-Enabled IoT Networks

This article studies simultaneous wireless information and power transfer (SWIPT) for unmanned aerial vehicle (UAV)-enabled Internet-of-Things (IoT) networks. Specifically, it is assumed that a single UAV wishes to simultaneously send common and private data streams as well as energy to multiple IoT nodes, in which the common stream should be recovered by all nodes while private streams are recovered only by the dedicated nodes. In addition, it is assumed that each node uses a power-splitting method that divides the received signal into two parts for energy harvesting and information decoding. Under this setting, by applying a concave-convex procedure (CCCP) method, we propose a novel algorithm that maximizes the minimum rate of private streams of IoT nodes by properly allocating the transmit power of each stream, adjusting the power-splitting ratios at IoT nodes, and designing the trajectory of the UAV, while the common rate and energy harvesting constraints at each node should also be satisfied. Moreover, to enable multiuser communication, a superposition coding in conjunction with successive interference cancellation (SIC) decoding is considered for SWIPT. The performance of the proposed scheme is evaluated and compared with benchmark schemes in various aspects by numerical simulations.

I. Introduction

Recently, unmanned aerial vehicles (UAVs) have received great attention in the fifth-generation (5G) or beyond 5G (B5G) communication. Due to their mobility capability, UAVs equipped with communication transceivers can offer new communication services that are difficult to support in conventional fixed infrastructures [1]–[7]. For example, UAVs can be employed to support public safety networks or resolve unexpected emergency situations much more cost efficiently and faster than the fixed infrastructures [1]–[4]. In addition, UAVs can provide seamless wireless connectivity to things or users that do not reach the coverage of terrestrial infrastructures, which plays an important role for realizing the Internet-of-Things (IoT) network to be everywhere [5]–[7]. On the other hand, the mobility of UAVs can also be leveraged to assist cellular communications [8]–[16]. For example, UAVs can serve as flying base stations (BSs) or relays to handle overloaded data traffic in cellular networks or to improve the coverage and the capacity of cellular networks [8]–[11]. Furthermore, UAVs can be effectively used to construct smart heterogeneous networks, since they can be dynamically and flexibly deployed to meet immediate communication needs [12]–[16]. Consequently, UAVs have been recognized as one of the important components in 5G or B5G communication systems [2]–[4].