RIS Enabled Multi-User SWIPT for URLLC

We consider an ultra-reliable low-latency system in which a reconfigurable intelligent surface (RIS) is deployed to assist the simultaneous wireless information and power transfer between the access point and multiple devices. The data transmission, in the form of short packets, is performed using the rate splitting mechanism with chase-combining hybrid automatic repeat request error control. Using a realistic channel model and considering operation in the presence of hardware impairments at the RIS and the devices, the system performance is investigated in two folds. First, the average block error rate and the outage probability in the information transfer are evaluated. Then, the battery recharging time in the power transfer and its statistics are determined. Numerical results are provided to illustrate the system performance and quantify the impacts of key parameters including the packet size, the maximum number of packet retransmissions, and the RIS size.