A Novel Beam Channel Model for AIRS-Assisted Mobile-to-Mobile Communication Systems

Due to the existence of wind and pressure variation, the unmanned aerial vehicle (UAV) will undergo pitch and roll wobbles in 3-D space, which will further induce the position offset of the aerial intelligent reflector surface (AIRS) deployed on the UAV platform. In this article, we consider the impact of the UAV pitch and roll wobbles and the effective AIRS structure, which is the projected structure of AIRS reflection unit in the signal propagation direction, on the channel statistical characteristics, and propose a novel AIRS-assisted beam channel model for mobile-to-mobile (M-to-M) multiple-input-multiple-output (MIMO) communication systems. In the proposed model, the relationship between the scattering gain of the AIRS unit and its size is also considered. Based the proposed model, the power scaling law of the AIRS-assisted link is derived, and it is demonstrated that the average received signal power is proportional to the square of the total geometric area of the AIRS in the far-field region. The simulation results show that the UAV wobbles with small angles significantly affects the spatial correlation function and the average received signal power, and the Doppler spread can be significantly reduced by increasing the number of AIRS reflection units. The simulation results also show that the effective AIRS structure in the signal propagation direction is essential in AIRS-assisted channel modeling and the proposed AIRS-assisted M-to-M MIMO communication system can obtain higher performance gain than traditional M-to-M MIMO communication system.