Intelligent Omni-Surfaces: Ubiquitous Wireless Transmission by Reflective-Refractive Metasurfaces

Intelligent reflecting surfaces (IRSs), which are capable of adjusting radio propagation conditions by controlling the phase shifts waves that impinge on surface, have been widely analyzed for enhancing performance wireless systems. However, reflective properties studied IRSs restrict service coverage to only one side surface. In this paper, extend communication systems, we introduce concept intelligent omni-surface (IOS)-assisted communication. More precisely, an IOS is important instance a reconfigurable surface (RIS) can provide mobile users (MUs) in and refractive manner. We consider downlink IOS-assisted system, where multi-antenna small base station (SBS) jointly perform beamforming, improving received power multiple MUs both sides IOS, through different reflective/refractive channels. To maximize sum-rate, formulate joint shift design SBS beamforming optimization problem, propose iterative algorithm efficiently solve resulting non-convex program. Both theoretical analysis simulation results show significantly extends when compared IRS.