439 research outputs found
Analytical Channel Model and Link Design Optimization for Ground-to-HAP Free-Space Optical Communication Networks
Integrating high altitude platforms (HAPs) and free-space optical (FSO)
communications is a promising solution to establish high data rate aerial links
for the next-generation wireless networks. However, practical limitations such
as pointing errors and angle-of-arrival (AOA) fluctuations of the optical beam
due to the orientation deviations of hovering HAPs make it challenging to
implement HAP-based FSO links. For a ground-to-HAP FSO link, tractable,
closed-form statistical channel models are derived in this paper to simplify
the optimal design of such systems. The proposed models include the combined
effects of atmospheric turbulence regimes (i.e., log-normal and gamma-gamma),
pointing error induced geometrical loss, pointing jitter variance caused by
beam wander, detector aperture size, beam-width, and AOA fluctuations of the
received optical beam. The analytical expressions are corroborated by
performing Monte-Carlo simulations. Furthermore, closed-form expressions for
the outage probability of the considered link under different turbulence
regimes are derived. Detailed analysis is carried out to optimize the
transmitted laser beam and the field-of-view of the receiver for minimizing
outage probability under different channel conditions. The obtained analytical
results can be applied to finding the optimal parameter values and designing
ground-to-HAP FSO links without resorting to time-consuming simulations.Comment: 11 pages, 13 figures, accepted on May 22, 2020, for publication in
IEEE/OSA Journal of Lightwave Technolog
Analytical Channel Model and Link Design Optimization for Ground-to-HAP Free-Space Optical Communications
Integrating high altitude platforms (HAPs) and free-space optical (FSO)
communications is a promising solution to establish high data rate aerial links
for the next-generation wireless networks. However, practical limitations such
as pointing errors and angle-of-arrival (AOA) fluctuations of the optical beam
due to the orientation deviations of hovering HAPs make it challenging to
implement HAP-based FSO links. For a ground-to-HAP FSO link, tractable,
closed-form statistical channel models are derived in this paper to simplify
the optimal design of such systems. The proposed models include the combined
effects of atmospheric turbulence regimes (i.e., log-normal and gamma-gamma),
pointing error induced geometrical loss, pointing jitter variance caused by
beam wander, detector aperture size, beam-width, and AOA fluctuations of the
received optical beam. The analytical expressions are corroborated by
performing Monte-Carlo simulations. Furthermore, closed-form expressions for
the outage probability of the considered link under different turbulence
regimes are derived. Detailed analysis is carried out to optimize the
transmitted laser beam and the field-of-view of the receiver for minimizing
outage probability under different channel conditions. The obtained analytical
results can be applied to finding the optimal parameter values and designing
ground-to-HAP FSO links without resorting to time-consuming simulations.Comment: 11 pages, 13 figures, accepted on May 22, 2020, for publication in
IEEE/OSA Journal of Lightwave Technolog
Statistical Modeling of FSO Fronthaul Channel for Drone-based Networks
We consider a drone-based communication network, where several drones hover
above an area and serve as mobile remote radio heads for a large number of
mobile users. We assume that the drones employ free space optical (FSO) links
for fronthauling of the users' data to a central unit. The main focus of this
paper is to quantify the geometric loss of the FSO channel arising from random
fluctuation of the position and orientation of the drones. In particular, we
derive upper and lower bounds, corresponding approximate expressions, and a
closed-form statistical model for the geometric loss. Simulation results
validate our derivations and quantify the FSO channel quality as a function of
the drone's instability, i.e., the variation of its position and orientation.Comment: This paper has been submitted to ICC 201
Evaluations of UAV-enabled FSO Communications in the Arctic
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
Communications-Aware Robotics: Challenges and Opportunities
The use of Unmanned Ground Vehicles (UGVs) and Unmanned Aerial Vehicles
(UAVs) has seen significant growth in the research community, industry, and
society. Many of these agents are equipped with communication systems that are
essential for completing certain tasks successfully. This has led to the
emergence of a new interdisciplinary field at the intersection of robotics and
communications, which has been further driven by the integration of UAVs into
5G and 6G communication networks. However, one of the main challenges in this
research area is how many researchers tend to oversimplify either the robotics
or the communications aspects, hindering the full potential of this new
interdisciplinary field. In this paper, we present some of the necessary
modeling tools for addressing these problems from both a robotics and
communications perspective, using the UAV communications relay as an example.Comment: 6 pages, 4 figures, accepted for presentation to the 2023
International Conference on Unmanned Aircraft Systems (ICUAS) at Lazarski
University, Warsaw, Polan
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