Joint Beamforming Designs for Intelligent Omni Surface Assisted Wireless Communication Systems

Intelligent reflecting surface (IRS) has been widely considered as one of key enabling techniques for the future wireless networks owing to its ability of constructing favorable propagation environment by controlling the phase shifts of reflected electromagnetic (EM) waves that impinge on the surface. While an IRS only focuses on the reflective implementation, recently emerged innovative concept of intelligent omni-surface (IOS) can provide the dual-functionality of manipulating signal reflection and transmission. Thus, an IOS can provide service coverage for both sides of it. In this paper, we consider an IOS-assisted multi-user multi-input single-output (MU-MISO) system, in which the IOS utilizes its reflective and transmissive properties to enhance the MU-MISO transmission. Our goal is to jointly optimize the transmit beamformers at base station (BS), the reflective and transmissive phase-shifts of IOS, and the reflection-to-transmission ratio of IOS to minimize the total transmit power for the MU-MISO system, subject to the signal-to-interference-plus-noise ratio (SINR) requirements of individual users. An efficient iterative algorithm is presented to solve this non-convex optimization problem. Simulation results verify the advantage of the IOS-assisted wireless communication system and the efficiency of the associate beamforming design algorithm.