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Today, satellite communications are the result of research in the field of communications, space and new technologies in shipping and trade, aiming to increase the coverage and manage the spectrum and the quality of services (QoS) with the lowest possible costs of implementation and maintenance. Apart from the research, satellite communications have also been part of the everyday life, as many applications that contribute to people’s everyday lives would be impossible to operate without them (e.g. positioning services that contribute to facilitating transport and navigation, or the weather forecast for emergency measures in adverse weather conditions). Satellite communications has also great contribution to telecommunication applications by providing global coverage and communication to anywhere on Earth, where there is no terrestrial network support.
Our research is focused to study, analysis and design of new efficient cooperative and resource management techniques for terrestrial mobile terminals, participating in an efficient hybrid terrestrial (5G) / satellite network, while making use of network coding schemes, proactive caching, multicast precoding techniques, as well as localization schemes.
The efficient combination of such competent communication schemes, will provide:
- increased coverage by one satellite
- reduction of the overall transmissions from the satellite, thus resulting in energy efficiency
- satellite and terrestrial network off-loading
- simultaneous transmission of different data types to multiple users with appropriate spectrum management techniques
- identification of external interference signals targeting to avoid intentional and unintentional interferers
We also deal with the following fields of research for satellite and terrestrial mobile communications:
- Narrowband Satellite IoT
- Hybrid Terrestrial/Satellite IoT Networks
- Cooperative satellite and terrestrial networks, relays, route diversity protocols, MIMO capacity evaluation, throughput and goodput calculations
- Radio Planning and Propagation Modeling: Static and long-term design (radio planning and dimensioning) of mobile, wireless and satellite networks, Cross-layer algorithms, Interference avoidance and mitigation techniques, Synergy of satellite and terrestrial wired and wireless networks, Quality of Service modeling and measurements
- Multiple access techniques such NOMA. Cooperation NOMA and Network Coding (NCMA scheme) in order to minimize latency/energy consumption and simultaneous provision of high throughput and QoS in hybrid Terrestrial/Satellite Networks
- Study and Development of Handover Techniques in Satellite Constellations exploiting advanced network coding technique
Also, the research team had developed a fully custom made simulator (MATLAB/C++) in orbital mechanics and communication link level and continue until now to maintain and update for research and development purposes:
The developed simulator:
- Predicts and performs real-time tracking of any space object that is in orbit around the Earth using Simplified Perturbations Models (SGP4 / SDP4)
- Calculates the propagation losses that occur in a satellite link in the various atmospheric layers of Earth using the ITU models.
- Calculates the Land Mobile Satellite channel losses using empirical and stochastic / statistical models, such as Loo, Corazza-Vatalaro, Karasawa, Lutz and Perez Fontan.
- Simulates the motion of satellite constellations, such as Iridium and Globalstar, as well as the performance (throughput, Bit Error Rate – BER) of the satellite link, both at physical and network layer.
- Gives results of the performance metrics of the satellite link (uplink, downlink) of the constellation’s satellites at physical and network layer.
National Strategic Reference Framework (NSRF), Education and Lifelong Learning
The success story of MIMO spans now for over a decade and has revolutionized all the aspects of wireless networks leading to its rapid embrace by the research community, standardization institutes and the industry. Application of MIMO technology to satellite and stratospheric communication systems have only recently begun to be investigated by academia and space agencies. The proposed research activity aims at shaping and enhancing the next generation fixed, mobile and hybrid satellite and stratospheric communication systems through MIMO techniques by contributing to both the theoretical and practical aspects of satellite technology. Another significant goal of the proposed activity is to create a Satellite Communications Network of Excellence in order to strengthen scientific and technological excellence on Satellite Communications (satcom) Technologies in Greece through the durable integration of the research capacities of the participants and having in view setting up in the long term a Hellenic Space Agency.
The research areas of the proposal are: a) Physical-Layer MIMO Techniques for next generation satcom and stratospheric systems, b) Multi-antenna terminal design for next generation satcom and stratospheric systems, c) Satellite and stratospheric MIMO radiochannel measurement campaign, d) Satellite and stratospheric MIMO radiochannel modeling, e) Satellite Communications and Stratospheric MIMO end-to-end system simulator and f) Various scenario applications including deep space communications and earth observation links. The expected results are: numerous contributions to standardization institutes (European Telecommunication Standardization Institute (ETSI), International Telecommunication Union-Radio (ITU-R), Digital Video Broadcasting (DVB)), scientific actions (COST), cooperation with European Space agencies (European Space Agency (ESA), German Aerospace Research Center (DLR), French Space Agency (CNES), French Aerospace Laboratory (ONERA), Italian Space Agency (ASI) etc) and numerous publications in the most prestigious Journals (IEEE) and Conferences relevant to Satellite and Wireless Communications and generally to Digital Communications.
- Derivation of a plethora of valuable results for the design of next generation fixed, mobile and hybrid satellite and stratospheric communication systems.
- Novel physical layer techniques for increasing capacity (multiplexing gain) and performance (coding and diversity gain).
- Development of efficient multiantenna terminal design methods.
- Conduct a state-of-the art MIMO radiochannel measurement campaign for various propagation scenarios.
- Novel realistic end-to-end system simulators with reference to recent satellite and industrial standards (e.g. DVB-S2, DVB-SH, DVB-RCS, DVB-NGH).
- A bulk of contributions to standardization institutes (ETSI, ITU-R, DVB), scientific actions (COST) is envisaged. International cooperation with European space agencies (ESA, DLR, CNES, ONERA etc).
- A series of research articles published in the most prestigious Journals and Conferences relevant to Satellite Communications and Digital Communications.
- Create and making of a critical mass of resources and expertise in order to set up a Network of Excellence and in Satellite Communications in Greece and, in the long term, creating a Hellenic Space Agency.
High Altitude Platforms for Communications and Other Services
COST297 – ‘HAPCOS’ was a European Action – now completed – dealing with HAPs and their applications. Representing an active group of researchers from academia, industry and governments, it has aimed to catalyse research activity, and to provide cohesion among the community. We included members from 20 European countries, and engaged active participation from across the world
Broadband Access Satellite Enabled Education
The overall objective of the BASE2 (Broadband Access Satellite Enabled Education) project is the implementation of an end-to-end system for tele-education applications, integrating broadband terrestrial networks with satellite broadband technologies. Aim of the project is to facilitate the sustainable provision of integrated tele- education services and applications to a large number of distributed interconnected sites over a variety of telecommunication infrastructures and the investigation of the seamless integration of low-cost satellite telecommunications infrastructures with broadband terrestrial systems. The project will integrate satellite communication technologies with various terrestrial network infrastructures. An integrated end-to-end system will be implemented in order to provide tele-education services to remote, distributed and isolated rural areas and maritime userswhere satellitecommunication technologieshave apotential edgeoverterrestrial infrastructures. Both oftheseuser groupsaretypical examplesof economicsectorsand activitiesthatcan benefitgreatlyby a wider deployment and use of satellite communications essentially due to the usually large distances which separate them from broadband terrestrial telecom infrastructures.
Mobile Application and Services based on Terrestrial and Satellite Interworking
The European satellite community is proceeding with great thrust towards the development of the innovative Satellite Digital Multimedia Broadcast (SDMB) concept, which will pave the way for an effective Satellite and Terrestrial network convergence. The SDMB system aims at complementing mobile networks with broadcast and multicast capabilities for a spectrum effective delivery of multimedia services on mobile devices. Taking advantage of the natural assets of satellite systems and of the full interoperability with terrestrial standards, the SDMB system will facilitate the successful deployment of UMTS, minimise geographical discrimination and foster multimedia usage adoption inEurope, effectively bridging the digital divide. Numerous studies, lead by the European Commission (e.g. MODIS, SATIN and RELY IST FP5 projects), the European Space Agency and National space agencies have contributed to the emergence of the SDMB concept, to secure the overall feasibility of the proposed innovations, to improve regulatory opportunities and to assess the market benefits.
Starting from this strong European knowledge base, the MAESTRO Integrated Project will proceed to specify, implement and validate the critical features of an SDMB system architecture. It aims at the highest possible degree of interoperability with terrestrial infrastructures with the objective to maximise its competitive assets and the underlying business rationale. Based on a solid consortium that achieves a balanced participation of terrestrial and satellite actors, the MAESTRO project will contribute to ensure wider adoption, broader availability of 3G and beyond 3G applications and services. In this perspective, MAESTRO is a unique opportunity for satellite communications to assure their role in the Generalised Access Network infrastructure, to foster the growth of the eEconomy and to improve European citizens welfare and safety.
Satellite UMTS IP Based Network
Project SATIN aims to investigate several new Satellite UMTS architectures that provide a range of new and complimentary packet based services to the terrestrial component of the UMTS. SATIN provides a fresh view as to the role of satellites within the overall UMTS design by focusing attention of using the satellite component as an effective and efficient access network for delivery of a wide range of packet-based and point-to-multipoint services. Based on the above architecture, SATIN will produce an optimised layer-1 and layer-2 design with full integration into the terrestrial UMTS core network in mind.