Power Minimization Under QOS Requirements for Low-Resolution Multiuser MIMO Systems With Reconfigurable Intelligent Surfaces Based Transmitter

The present study considers a virtual multiuser multiple-input multiple-output system with PSK modulation realized via the reconfigurable intelligent surface-based passive transmitter setup. The study considers a discrete phase shift reconfigurable intelligent surface model where the reflecting elements' coefficients are restricted to a discrete set. With this, a symbol-level precoding power minimization problem under the condition that the union-bound symbol-error probability is below a given requirement is formulated. The corresponding mixed integer problem is solved via the utilization of a sophisticated branch-and-bound strategy. Numerical results show that the proposed power minimization approach yields reduced average transmit power when compared to state-of-the-art techniques.