Intelligent Reflecting Surfaces for Free Space Optical Communications

Abstract

In this paper, we investigate the use of intelligent reflecting surfaces (IRSs) (i.e., smart mirrors) to relax the lineof-sight requirement of free space optical (FSO) systems. We characterize the impact of the physical parameters of the IRS, such as its size, position, and orientation, on the quality of the end-to-end FSO channel. In addition, we develop a statistical channel model for the geometric and the misalignment losses which accounts for the random movements of the IRS, transmitter, and receiver due to building sway. This model can be used for performance analysis of IRS-based FSO systems. Our analytical results shows that depending on the angle between the beam direction and the IRS plane, building sway for the IRS has either a smaller or larger impact on the quality of the end-to-end FSO channel than building sway for the transmitter and receiver. Furthermore, our simulation results validate the accuracy of the developed channel model and offer insight for system design.

Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead

“…In [246], the authors consider the application of RISs in order to alleviate the line-of-sight requirement in free space optical systems. The authors develop conditional and statistical channel models that characterize the impact of the physical parameters of an RIS, which include the size, position, and orientation, on the quality of the end-to-end channel.…”

Intelligent Surface-Aided Transmitter Architectures for Millimeter-Wave Ultra Massive MIMO Systems

“…, N , where each subset is responsible for reflection/transmission of the signal of one of the active antennas, cf. (20). For PI, the positioning of the active antennas minimizes the interference between the different subsets of passive antennas M n , n = 1, .…”

Reconfigurable Intelligent Surface assisted Two–Way Communications: Performance Analysis and Optimization

“…The corresponding optimal phases are φ ⋆ ℓ = ϕ ℓ + ψ ℓ for both users with reciprocal channels, φ ⋆ ℓ = ϕ r,ℓ +ψ t,ℓ for U 1 with non-reciprocal channels, and φ ⋆ ℓ = ϕ t,ℓ + ψ r,ℓ for U 2 with non-reciprocal channels. It is important to note that there is no loop interference, i.e., σ 2 i = 0 in (4), (5), (7) or (8). Therefore, the SNR of Scheme 2 is always larger than the SINR of Scheme 1, and achieves lower outage probability which can easily be deduced from (16) and (22) replacing ρ as ρ = P/σ 2 w .…”