A Unified Statistical Model for Atmospheric Turbulence-Induced Fading in Orbital Angular Momentum Multiplexed FSO Systems

Abstract

This paper proposes a unified statistical channel model to characterize the atmospheric turbulence induced distortions faced by orbital angular momentum (OAM) in free space optical (FSO) communication systems. In this channel model, the self-channel irradiance of OAM modes as well as crosstalk irradiances between different OAM modes are characterized by a Generalized Gamma distribution (GGD). The latter distribution is shown to provide an excellent match with simulated data for all regimes of atmospheric turbulence. Therefore, it can be used to overcome the computationally complex numerical simulations to model the propagation of OAM modes through atmospheric turbulent FSO channels. The GGD allows obtaining very simple tractable closed-form expressions for a variety of performance metrics. Indeed, the average capacity, the bit-error rate, and the outage probability are

Efficient and Secure Bit-Level Chaos Security Algorithm for Orbital Angular Momentum Modulation in Free-Space Optical Communications

“…The correlation distributions in the three directions of two neighboring pixels are demonstrated in Figs. (5)(6)(7). It is displayed from the figures that, the original video frame distributions for any two contiguous pixels are highly concentrated, which implies that these video frames have strong correlation between pixels.…”

“…where x is the transmitted encrypted data {0, 1}, I is the received irradiance, η is the optical to electrical conversion coefficient, N is the additve white Gaussian noise (AWGN) with zero mean and variance N 0 . The received irradiance is given by [5]:…”

“…To get the value of E[I], the following expression is estimated [5], [57]: From [56], [57], we have:…”

“…The orbital angular momentum (OAM) analogous to optical transmission systems is suggested to transmit multiple signals via free-space channels [5]- [7]. The orthogonality of OAM beams enabling propagation without signal interference allows simultaneous transmission of information on OAM modes.…”

Performance Analysis of 3D Video Transmission Over Deep-Learning-Based Multi-Coded N-ary Orbital Angular Momentum FSO System

“…However, in a strong turbulence regime, optical power spreads widely and there is significant power leakage to other OAM modes. The latter is mode dependent and causes a loss of orthogonality between OAM modes, resulting in loss disparities known as mode-dependent loss (MDL), which causes system performance degradations [38], [41], [42].…”