A5068925211- Satellite Communication Systems
- Precipitation Measurement and Analysis
- Radio Wave Propagation Studies
- Optical Wireless Communication Technologies
- Advanced Wireless Communication Techniques
- Wireless Communication Networks Research
- Advanced MIMO Systems Optimization
- Telecommunications and Broadcasting Technologies
- Millimeter-Wave Propagation and Modeling
- Advanced Optical Network Technologies
- Power Line Communications and Noise
- Spacecraft Design and Technology
- IoT Networks and Protocols
- Optical Network Technologies
- Cooperative Communication and Network Coding
- Meteorological Phenomena and Simulations
- UAV Applications and Optimization
- Adaptive optics and wavefront sensing
- Hydrology and Drought Analysis
- Mobile Ad Hoc Networks
- GNSS positioning and interference
- Opportunistic and Delay-Tolerant Networks
- Distributed systems and fault tolerance
- Financial Risk and Volatility Modeling
- Wireless Networks and Protocols
National Technical University of Athens
2012-2021
Science and Technology Facilities Council
2018
National and Kapodistrian University of Athens
2013-2017
Office National d'Études et de Recherches Aérospatiales
2011
Summary The space environment is still challenging but becoming more and attractive for an increasing number of entities. In the second half 20th century, a huge amount funds was required to build satellites gain access space. Nowadays, it no longer so. advancement technologies allows producing very small hardware components able survive strict conditions outer Consequently, can be designed wide set missions keeping low design times, production costs, deployment costs. One widely used type...
This paper deals with the problem of precoding, scheduling, and link adaptation in next generation mobile interactive multibeam satellite systems. In contrast to fixed services, when user terminals move across coverage area, additional challenges appear. Due time varying channel, gateway has only access a delayed version channel state information (CSI), which can eventually limit overall system performance. However, general multiuser multiple-input multiple-output terrestrial systems, CSI...
The impact of cloud impairments on satellite links is increasing with the employment higher frequency bands. In this paper, a model for predicting attenuation statistics communication systems operating from Ka-band to optical range presented. must be accurately quantified reliable design systems. A stochastic dynamic generation integrated liquid water content (ILWC) fields proposed. based differential equations and incorporates spatial temporal behavior ILWC. Classifying types vertical...
Satellite communication networks at optical frequencies have been proposed to provide a very high throughput for backhauling applications. In this letter, the monthly variation of cloud coverage statistics is investigated and exploited optimum selection ground stations. Optimization algorithms minimum number stations satisfying availability requirements total network are given. The active per month calculated. Numerical results models presented.
Analytical models for the prediction of cloud-free line-of-sight (CFLOS) probability a single optical satellite link and multiple spatially separated links are presented. The presence clouds along slant paths causes their blockage. As result, an ON/OFF channel with is assumed. proposed model calculation CFLOS considers elevation angle links, altitude ground stations, spatial variability clouds. methodology based on assumption that integrated liquid water content (ILWC) follows lognormal...
In this paper, the performance of a reference medium earth orbit (MEO) satellite constellation system operating at Ka-band and employing single links to ground is compared with next generation advanced systems in higher RF or optical bands multiple diversity links. The fill rate existing MEO constellations offering broadband trunking services growing fast, rendering search for additional spectrum vital importance. Therefore, paper reports on results study investigating option using Q/V-band,...
A novel model based on the bivariate inverse Gaussian (IG) distribution is presented for prediction of outage performance a dual site diversity Earth-space system. In present paper, exceeded rain attenuation induced each path assumed that follows IG distribution. The joint exceedance probability calculated using long-term statistical parameters individual slant and adopting spatial correlation coefficient variables as function separation distance two Earth-stations. Earth-Space Database...
Modern satellite communication networks will employ frequencies above 10GHz. At these frequency bands, rain attenuation is the dominant fading mechanism. In this paper, a novel channel model, synthesizer for generating time series links operating at 10GHz and presented. The proposed model modifies Maseng-Bakken (M-B) since it generates that follow Weibull distribution. new stochastic dynamic based on first-order Stochastic Differential Equations (SDEs) considers induced slant path as...
In this letter, a simple engineering scheme for achieving optimal dynamic capacity allocation in geostationary and medium Earth orbit multi-beam high throughput satellite systems is presented. Exploiting smart gateway diversity setup considering users' requested gateways' offered capacities, we propose theoretically optimal, based on Monge arrays, minimization of both system's losses rate matching performance metrics. This has low complexity the appropriate sorting capacities. Finally,...
The Land Mobile Satellite (LMS) channel at 2 GHz is examined and the first order statistics are modeled using experimental data for two tree shadowing scenarios. Considering that of used as input to models well calculation system margins, modeling probability density function (PDF) cumulative distribution (CDF) received signal envelope great importance design LMS systems. Experimental from measurements performed in Prague, Czech Republic, presented scenarios, a Heavy Tree Shadowing one an...
In this paper, a new rain-attenuation stochastic dynamic channel model for low Earth orbit (LEO) satellite links operating above 10 GHz is proposed, taking into account the time dependence of elevation angle and its impact on dynamics. The synthesizer based first-order differential equations (SDEs) extends well-known Maseng-Bakken (M-B) fixed communication links. Moreover, an analytical closed-form expression parameter derived used in proposed synthesizer. validated terms LEO-slant-path...
The upcoming migration of satellite services to higher bands, namely the Ka- and Q-bands offers many advantages in terms bandwidth, data rates system capacity. However, it poses challenges as propagation effects introduced by various atmospheric phenomena are particularly pronounced these bands can become a serious constraint reliability performance. This paper outlines goals, organization some first results an ongoing large campaign consortium formed across Europe under supervision European...
Summary The upcoming migration of satellite services to higher bands, namely, the Ka‐ and Q/V‐bands, offers many advantages in terms bandwidth system capacity. However, it poses challenges as propagation effects introduced by various atmospheric phenomena are particularly pronounced these bands can become a serious constraint reliability performance. This paper presents goals, organisation, preliminary results an ongoing large‐scale European coordinated campaign using Alphasat Aldo Paraboni...
This contribution is focused on MEO satellite communication systems operating at optical wavelengths, and especially the optimum dimensioning of their ground station (OGS) network (OGSN). The objective optimization to minimize size network, while still ensuring target link availabilities due cloud blockage. Two new algorithms for this selection OGSs are proposed. take into account monthly variability coverage, advantage locations in different hemispheres, select OGSs, which within visibility...
The present paper proposes a novel model based on Copulas for predicting the outage probability experienced in Earth-space site diversity systems. In satellite communication networks, increase of operating frequencies above 10 GHz, which is mainly driven by need higher bandwidth, results heavier signal attenuation due to various atmospheric effects. Precipitation and rain induce high over earth-space links most important factor limiting both links' availability reliability. order mitigate...
In this article, optimal assignments, for various performance metrics, in multibeam high-throughput smart gateway diversity satellite systems operating at extremely high frequencies are studied. The minimization of the objectives total system's capacity losses and rate matching achieved same time, satisfaction ratio is maximized. offered requested capacities system as well dynamic variations atmospheric channels considered analysis. efficient Hungarian algorithm adopted to provide an pairing...
A new stochastic dynamic model for the generation of rain attenuation time series fixed satellite and Line-of-sight (LOS) terrestrial links operating above 10 GHz is presented. The model's concept originate from classic Maseng-Bakken (M-B) approach apart that it generates Gamma distributed time-series not lognormal as in M-B approach. Gamma-distributed are typical at heavy climatic regions where expected to perform better than M-B. comparison with experimental results terms exceedance...
This Letter examines optimal capacity allocation schemes in multi-beam high-throughput satellite systems exploiting the smart gateway diversity setup. Considering user beams' requested and gateways' offered capacities, we propose theoretically optimal, based on Monge arrays, different for maximization of minimum total system's satisfaction ratios. These have low complexity appropriate sorting capacities. Furthermore, theoretical analysis results dilemma giving priority to performance,...
This letter analytically derives the statistical distribution of carrier-to-noise-plus-interference ratio (CNIR) due to adjacent satellite interference for Earth stations on mobile platforms operating in Ku and Ka frequency bands. At these bands, problem, which is especially pronounced terminals, further aggravated by propagation effects, predominantly rain attenuation. The characterization resulting CNIR paramount importance design new broadband systems based digital video broadcasting via...
Cognitive Radio (CR) is a promising technology for the flexible spectrum utilization in wireless communications. Very recently, there has been increasing interest applicability of CR techniques satellite communication systems. This paper investigates impact propagation phenomena co-existence scenario uplink Fixed Satellite Service (FSS) and terrestrial (FS) systems operating Ka-band. Specifically, we analytically derive Signal-to-Interference Ratio (SIR) Signal-to-Noise plus Interference...
In this paper, the performance of multibeam high throughput satellite systems, which employ smart gateway diversity concept, is investigated and various capacity allocation schemes are examined. These systems operate at frequencies above 20 GHz. To study system's losses, impact total atmospheric attenuation incorporated a novel flexible dynamic scheme proposed based on offered capacities gateways requested users' beams. Specifically, constitute metric, determined as summation difference...
Summary In this paper, a methodology for the generation of cloud coverage time series correlated on both temporal and spatial domains estimation cloud‐free line‐of‐sight (CFLOS) probability single optical ground station (OGS) network OGSs (multiple OGS) medium earth orbit (MEO) constellation satellite communication systems is presented. Spatial diversity employed as mitigation technique against blockage to increase availability an OGS (OGSN). second part effective algorithm based ant colony...
In this paper, we study the performance of satellite-based sensor networks. particular, consider dense networks M2M devices deployed in several geographical locations. The are locally grouped into clusters and communicate with a satellite gateway. proposed network architecture is potential solution for remote monitoring surveillance usually on border non-habitable areas. We also employment Ka band broadband connection. Consequently, an efficient clustering methodology while feasibility...