Multi-User Full-Duplex Reconfigurable Intelligent Surface Assisted Wireless Powered IIoT Networks

This paper investigates a full-duplex (FD) reconfigurable intelligent surface (RIS)-assisted wireless powered communication network (WPCN) in which FD multi-user (FD-MUs) industrial internet-of-things (IIoT) sensor devices with energy harvesting (EH) capabilities communicate with an FD hybrid-access point (FD-AP). The FD-AP with dual-set of multiple antennas use a set of antennas to beamform energy in downlink (DL) transmission and the other set of antennas to receive information signals in uplink (UL) transmission from the dual-set of single antenna FD-MUs. The FD-MUs use one single antenna to receive energy signals, while the other single antenna is used to transmit information. For comparison, two special cases of the FD-FD RIS-assisted WPCN IIoT network are considered. The first scenario considers an FD-HD (half-duplex) RIS-assisted WPCN IIoT network made up of a FD-AP and HD-MUs while the second comprises an HD-HD RIS-assisted WPCN IIoT network consisting of HD-AP and HD-MUs. We investigate the sum-rate performance of the FD-FD system with random IRS phase shifts and compare it to FD-HD and HD-HD system models. It is shown from simulation results that the FD-FD system outperforms the two special cases in the low transmit power regime.