The Measurement-based Intelligent Reflecting Surfaces Path Loss Model

Intelligent reflecting surface (IRS) can control the reflection of electromagnetic wave, so the deployment of IRS can adjust the channel conditions to enhance the coverage and throughput in the 5G evolution networks. Since the IRS is only capable of passively reflecting the received signals by adjusting the phase-shift, its path-loss modelling method is different from existing two-hop communication networks, such as repeater, or relay. In this paper, the path-loss model for IRS in real urban scenario is proposed. Based on the theoretical analysis, the novel measurement methodology is proposed that the path-loss channel measurement campaign can be divided into separate measurement and cascade measurement, so that the measurement efficiency is dramatically improved under the constraint of modelling accuracy. The measurement data at 3.7 GHz verifies the accuracy of the proposed IRS path-loss model with the root mean squared error (RMSE) as 2.33 dB. The work investigated in this paper could be the foundation for IRS-based network link budget calculation and system level evaluation.