Composite Fading Model for Aerial MIMO FSO Links in the Presence of Atmospheric Turbulence and Pointing Errors

Khallaf, Haitham S.; Kato, Kazutoshi; Mohamed, Ehab Mahmoud; Sait, Sadiq M.; Yanıkömeroğlu, Halim; Uysal, Murat

doi:10.1109/lwc.2021.3064832

Cited by 13 publications

(8 citation statements)

References 18 publications

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“…A probability distribution function of the C 2 n values from the experiment could be computed to determine if this adhered to relevant channel probability distribution functions for FSO spatial mode diversity and FSO aerial communications such as Malaga, log normal, Gamma-Gamma, Nagakami, and others [68][69][70][71][72]. Log normal and Gamma-Gamma channel models are considered as special cases of the Malaga channel model, for weak turbulence and moderate-strong turbulence, respectively [72].…”

Section: Resultsmentioning

confidence: 99%

Post-Flood UAV-Based Free Space Optics Recovery Communications with Spatial Mode Diversity

et al. 2022

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The deployment of unmanned aerial vehicles (UAVs) for free space optical communications is an attractive solution for forwarding the vital health information of victims from a flood-stricken area to neighboring ground base stations during rescue operations. A critical challenge to this is maintaining an acceptable signal quality between the ground base station and UAV-based free space optics relay. This is largely unattainable due to rapid UAV propeller and body movements, which result in fluctuations in the beam alignment and frequent link failures. To address this issue, linearly polarized Laguerre–Gaussian modes were leveraged for spatial mode diversity to prevent link failures over a 400 m link. Spatial mode diversity successfully improved the bit error rate by 38% to 55%. This was due to a 10% to 19% increase in the predominant mode power from spatial mode diversity. The time-varying channel matrix indicated the presence of nonlinear deterministic chaos. This opens up new possibilities for research on state-space reconstruction of the channel matrix.

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Section: Resultsmentioning

confidence: 99%

Post-Flood UAV-Based Free Space Optics Recovery Communications with Spatial Mode Diversity

et al. 2022

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“…Specifically for SOC, the receiving telescope plays a vital role. It incorporates a PD for direct detection, facilitating a precise light signal focusing and collection before being directed to the PD, as observed in applications as SOC and astronomical observations [5], [6]. Unlike OWC, SOC signals must travel long distances, requiring innovative laser transmitters to facilitate long-range OWC connections.…”

Section: A Backgroundmentioning

confidence: 99%

“…The authors in [12] consider utilizing a Lognormal distribution for OWC to accurately represent the atmospheric modeling in weak turbulence regime. On the other hand, the Gamma-Gamma distribution is more suitable for strong turbulence regime [6]. The authors in [13] proved that double Generalized Gamma distribution is an appropriate statistical model to represent the irradiance fluctuations in strong and weak turbulence regimes for OWC.…”

Section: ) Channel Modelingmentioning

confidence: 99%

Symbol Detection and Channel Estimation for Space Optical Communications Using Neural Network and Autoencoder

Elfikky,

Rezki

2024

Trans. Mach. Learn. Comm. Netw.

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Optical wireless communications in space are degraded by atmospheric turbulence, light attenuation, and detector noise. In this paper, we develop a neural network (NN) channel estimator that is optimized across a wide range of signal-to-noise ratio levels during the training stage. In addition, we propose a novel autoencoder (AE) model to develop a complete physical layer communication system in space optical communications (SOC). The AE is designed to work with both perfect and imperfect channel state information (CSI), providing a flexible and versatile solution for SOC. Batch normalization and multiple-decoders are incorporated into the proposed AE, which improves receiver learning capabilities by allowing the use of more than one path to update encoder and decoder weights. This novel approach can reduce the error in detection relative to state-of-the-art models. Using the system tool kit simulator, we examine our system's performance in a downlink SOC channel that connects a geostationary satellite to a ground station in Log-normal fading channel. Furthermore, we evaluate the performance of our system in a downlink channel that establishes a connection between a Low Earth Orbit satellite and a ground station, operating in Gamma-Gamma fading channel. The numerical results show that the proposed channel estimator NN is superior to state-of-the-art learning-based frameworks and achieves the same level of performance as the minimum mean square error estimator. Additionally, with no fading and for both perfect and imperfect CSI with different code rates and fading channels, the proposed AE-based detection outperforms both benchmark learning frameworks and most popular convolutional codes.INDEX TERMS Deep learning, channel estimation, symbol detection, space optical communications, system tool kit.

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“…The attenuation caused by snow is highly variational and depends on the density and size of snow crystals. FSO links through snow are affected and degraded in a major way due to the signal attenuation [27]. The attenuation coefficient is given by [28]…”

Section: Modeling Effects Of Snow On a Fso Linkmentioning

confidence: 99%

Evaluations of UAV-enabled FSO Communications in the Arctic

Pottoo

Ellingsen

2022

2022 IEEE/SICE International Symposium on System Integration (SII)

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This paper investigates the feasibility of using free space optics (FSO) for communication between multiple hovering unmanned aerial vehicles (UAVs) and a detection unit (DU) in the Arctic. The uniqueness that sets apart UAV-based FSO systems from conventional FSO systems is the dynamics of the system since location and inclination of the UAV changes over time due to wind load and UAV oscillations. The envisioned scenario consists of UAVs equipped with laser diodes and a DU mounted on top of a ship. We propose an application scenario of search and rescue (SAR) operations in the High North. In the system design, the SAR team establishes communication with UAVs using radio frequency multiple-access links while DU demodulates the information from the incoming FSO fronthaul signals. Furthermore, statistical models for the FSO channel, random position and orientation fluctuations, snow, and fog have been derived. This work amplifies the need and possibility of enabling enhanced accessibility and connectivity in the Arctic utilizing UAVs and FSO.

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Composite Fading Model for Aerial MIMO FSO Links in the Presence of Atmospheric Turbulence and Pointing Errors

Cited by 13 publications

References 18 publications

Post-Flood UAV-Based Free Space Optics Recovery Communications with Spatial Mode Diversity

Post-Flood UAV-Based Free Space Optics Recovery Communications with Spatial Mode Diversity

Symbol Detection and Channel Estimation for Space Optical Communications Using Neural Network and Autoencoder

Evaluations of UAV-enabled FSO Communications in the Arctic

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