3D Geometry-Based Channel Model for Intelligent Reflecting Surface-Assisted MIMO Communications

Intelligent reflecting surface (IRS) has been regarded as an emerging technology, which can significantly enhance the coverage and capacity of next-generation wireless networks. An accurate and easy-to-use channel model is essential to the deployment and evaluation of IRS-assisted communication systems. In this paper, we propose a 3D geometry-based channel model for the IRS-assisted multiple-input-multiple-output (MIMO) communications, and its corresponding parameters are obtained by channel measurement to better capture the underlying propagation characteristics. First, a cascaded channel model considering the relationship between the reflection amplitude and the angle of signal is presented. With the cascaded channel model, a channel coefficient generation procedure based on the 3GPP technical report 38.901 is proposed for IRS-assisted communication systems. To generate the cascaded channel, a response function that satisfies the reciprocity of uplink and downlink channels is derived. Then a channel measurement campaign at 3.7GHz is carried out to obtain some small-scale parameters for the IRS scenario. Finally, the proposed statistical channel model is implemented on a system-level simulation platform and some channel characteristics are analyzed to validate its rationality.