Cloud Attenuation Statistics Prediction From &lt;italic&gt;Ka&lt;/italic&gt;-Band to Optical Frequencies: Integrated Liquid Water Content Field Synthesizer

Efrem

et al. 2018

Self Cite

Summary In this paper, a methodology for the generation of cloud coverage time series correlated on both temporal and spatial domains and the estimation of cloud‐free line‐of‐sight (CFLOS) probability for a single optical ground station (OGS) and a network of OGSs (multiple OGS) for medium earth orbit (MEO) constellation satellite communication systems is presented. Spatial diversity is employed as a mitigation technique against cloud blockage to increase the availability of an OGS network (OGSN). In the second part of the paper, an effective algorithm based on the ant colony optimization (ACO) algorithm is proposed for the optimum selection of OGSs forming an OGSN. The proposed algorithm takes into consideration the spatial correlation between the OGSs. In the simulation results section, a MEO constellation system with 12 MEO satellites has been assumed. The integrated liquid water content (ILWC) statistical parameters that are necessary for the CFLOS time series are taken from ECMWF Re‐Analysis (ERA)‐Interim database, European Centre for Medium‐Range Weather Forecasts (ECMWF). Finally, numerical results for the optimum selection of OGSs using the proposed methodology are exhibited and commented. Interesting conclusions are drawn, and future work with technical challenges is briefly described.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Medium earth orbit optical satellite communication networks: Ground terminals selection optimization based on the cloud‐free line‐of‐sight statistics

Efrem

et al. 2018

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Ground‐to‐GEO optical feeder links for very high throughput satellite networks: Accent on diversity techniques

Mengali

et al. 2020

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This paper studies the use of optical feeder links in very high throughput satellites (VHTS) networks with emphasis on gateway diversity techniques to mitigate the inherent propagation losses in optical frequencies. Focusing on a GEO scenario, the paper considers a system-wide approach investigating various challenges of optical feeder links. These include transmission schemes amenable for transparent on-board processing, optical channel models taking into account blockage by clouds and fading caused by atmospheric turbulence in addition to complexity of on-board and on-ground processing. The channel models are then used to dimension the ground segment towards ensuring a given availability percentage (e.g., 99.9%). The channel model and payload complexity further influence the choice of link layer techniques used for counteracting fading due to atmospheric turbulence in the absence of blockage. An elaborate end-to-end simulator incorporating the proposed channel models capturing the nuances of various processing blocks like optical-electrical conversion is developed. The system performance results provide interesting insights and a framework for assessing the feasibility and advantages of optical feeder links in VHTS systems. K E Y W O R D Sanalog and digital transparent payloads, channel models, GEO networks, microdiversity and macrodiversity, optical feeder links, optical ground station network selection, optical received time series, optical SNR | INTRODUCTIONA key challenge towards future generation very high throughput satellites (VHTS) is the limited spectrum of about 2 GHz available in the Ka band (20/30 GHz). A potential solution for resolving this issue could be to move the feeder links from the Ka band to the Q/V band (40/50 GHz) 1-4 or even to the W band (70/80 GHz) 5 where bandwidths of up to 5 GHz are available. While this allows for the use of radio frequency (RF) domain expertise, the bandwidth available is limited compared with requirement estimates and the spectrum is also solicited in the emerging 5G paradigm. 6 Another revolutionary solution is to move the feeder link from RF frequencies to optical frequencies. [7][8][9] Both these approaches are challenging due to the attenuation by atmospheric phenomena (e.g., rain and clouds) whose severity increases with the frequency. In both cases, a network of multiple gateways with smart switching capabilities is thus envisaged. 10,11 While RF at high frequencies is less impaired than the optical counterpart, larger number of gateways is nonetheless required to achieve very high throughputs due to the limited available bandwidth per

Scintillation due to atmospheric turbulence on optical GEO and MEO satellite links: Time series synthesizer for system level simulations

Panagopoulos

2020

SummaryOptical satellite links have been proposed in order to cover the increasing capacity demand for satellite networks. The reliable design of the performance of optical satellite links is of utmost importance. In the present paper, an analytical methodology for the generation of time series of scintillation due to atmospheric turbulence of optical satellite links is proposed. Under cloud‐free line of sight, scintillation causes the degradation of link's quality. In order to design adaptive transmission techniques for scintillation compensation, an accurate channel model for time series synthesis is required. The proposed synthesizer is based on stochastic differential equations (SDEs) driven by fractional Brownian motion and generates log‐amplitude time series for plane and spherical waves affected by turbulence. The links are considered between Ground and Geostationary or Medium Earth Orbit satellites. The synthesizer is validated using the theoretical aspects of scintillation considering the first‐ and second‐order statistics. Additionally, the performance of the synthesizer for the case of Geostationary is validated with data from ARTEMIS optical satellite link experiment carried out by European Space Agency. The proposed synthesizer can be directly employed for the system performance of transmission techniques for optical satellite forward and reverse links taking into account the scintillation effects.