Impact of nonzero boresight pointing error on ergodic capacity of MIMO FSO communication systems

Ruben-Boluda-Ruiz, Antonio García-Zambrana, Beatriz del Castillo-Vázquez, Carmen Castillo-Vázquez
January 2016
Cite DOI URL

Abstract

A thorough investigation of the impact of nonzero boresight pointing errors on the ergodic capacity of multiple-input/multiple-output (MIMO) free-space optical (FSO) systems with equal gain combining (EGC) reception under different turbulence models, which are modeled as statistically independent, but not necessarily identically distributed (i.n.i.d.) is addressed in this paper. Novel closed-form asymptotic expressions at high signal-to-noise ratio (SNR) for the ergodic capacity of MIMO FSO systems are derived when different geometric arrangements of the receive apertures at the receiver are considered in order to reduce the effect of nonzero inherent boresight displacement, which is inevitably present when more than one receive aperture is considered. As a result, the asymptotic ergodic capacity of MIMO FSO systems is evaluated over log-normal (LN), gamma-gamma (GG) and exponentiated Weibull (EW) atmospheric turbulence in order to study different turbulence conditions, different sizes of receive apertures as well as different aperture averaging conditions. It is concluded that the use of single-input/multiple-output (SIMO) and MIMO techniques can significantly increase the ergodic capacity respect to the direct path link when the inherent boresight displacement takes small values, i.e. when the spacing among receive apertures is not too big. The effect of nonzero additional boresight errors, which is due to the thermal expansion of the building, is evaluated in multiple-input/single-output (MISO) and single-input/single-output (SISO) FSO systems. Simulation results are further included to confirm the analytical results. © 2016 Optical Society of America.

Type
Journal article
Publication
Optics Express
Atmospheric Turbulence Channel Capacity Errors Optical Communication Signal Receivers Thermal Expansion Turbulence Models Asymptotic Expressions Equal-Gain Combining Exponentiated Weibull Free Space Optical Systems High Signalto-Noise Ratios (SNR) Multiple Input/Multiple Outputs Single Input/Single Outputs Turbulence Conditions Signal to Noise Ratio
Antonio García-Zambrana
Antonio García-Zambrana
Professor of Telecommunications Engineering

Professor at the University of Málaga working on wireless optical communications, free-space optical links, underwater optical wireless communications, visible light communications, and FPGA/RFSoC-based real-time prototyping.

Beatriz del Castillo-Vázquez
Beatriz del Castillo-Vázquez
Associate Professor of Telecommunications Engineering

Associate Professor at the University of Málaga working on wireless optical communications, free-space optical links, underwater optical wireless communications, optical channel modelling and system-level performance analysis.