SWIPT MISO Wireless Communication System via Intelligent Reflecting Surface

Intelligent reflecting surfaces (IRS) have recently received notably attention in the field of wireless communications research. This technology has a unique ability to control the wireless propagation environment, which is not possible in traditional wireless networks. This paper investigates a multiple-input single-output (MISO) IRS-assisted simultaneous wireless information and power transfer (SWIPT) system. This system involves a base station (BS) installed on an unmanned aerial vehicle (UAV) concurrently sends information to information-decoding receivers (IDRs) and transfers energy to energy-harvesting receivers (EHRs). Unlike conventional SWIPT systems with fixed transmitters, UAV-mounted BSs can flexibly provide wireless services to ground users in three-dimensional (3D) space. Incorporating UAV and IRS into the SWIPT systems enhances the quality of service (QoS) for IDRs and EHRs. The primary objective of the proposed system is to maximize the weighted sum rate of the IDRs by simultaneously optimizing the phase shifts of the IRS as well as the precoding vectors at the UAV. To achieve this, we propose the utilization of Dinkelbach's algorithm, which allows us to optimize all the variables jointly with an acceptable complexity. The results of the simulation indicate that the deployment of the IRS in the SWIPT system enhances the spectral efficiency of IDRs and the energy efficiency of EHRs compared to the system without IRS. Furthermore, numerical results are provided to assess the performance of our proposed approach in comparison to other design schemes.