Low-Overhead Kronecker-Based Intelligent Reflective Surfaces for 5G and Beyond

Intelligent Reflective Surfaces (IRSs) typically require element-wise control, which necessitates complex wiring systems and leads to higher power consumption. Additionally, the number of control signals needed for each configuration equals the number of IRS elements, resulting in substantial control overhead and challenges in achieving rapid configuration changes. In order to not only simplify the control mechanism but also enhance the overall efficiency of IRS-assisted wireless networks by mitigating these drawbacks, we present a novel approach for controlling the phase shifts introduced by IRS elements. This approach incorporates a Kronecker structure into the phase-shifting matrix, enabling more efficient implementation and control. Consequently, our method significantly reduces the number of control signals required compared to traditional element-wise control methods. We jointly optimize active and passive beamforming for downlink communication in a controllable IRS-assisted wireless network to evaluate the performance of our proposed method.