IRS-Enabled Monostatic Backscatter MIMO Communication Design for V2I Networks

Future vehicle-to-infrastructure (V2I) wireless networks are meeting unprecedented challenges regarding the high energy consumption problem caused by the large number of radio frequency (RF) emitters deployed. The backscatter communication (BackCom) and Intelligent Reflecting Surface (IRS) techniques can achieve low-power transmission while implementing effective beamforming. Thus, this paper leverages these two techniques into V2I communication systems, where multiple IRSs transmit roadside information to a multi-antenna vehicle by backscattering the vehicle's signals. Considering the self-interference and two optimization methods at the vehicle, i.e., post-detection (PD) and integrated detection (ID), we formulate two weighted sum-rate maximization problems. The detection matrix and transmit power at the vehicle, as well as the IRS reflection coefficients, are jointly designed based on an alternating algorithm. The simulation results validate the convergence performance of the proposed algorithm, the feasibility of the introduced system model, and the effectiveness of the optimization scheme.