23 research outputs found
Overview of SES's Innovation Activities on Satellite Integration into 5G
No full textThis presentation will provide an overview of the R&D and innovation activities, in which SES is actively involved to promote the satellite integration into 5G. Main emphasis will be put on the European Commission H2020 5G PPP Phase 2 project “SaT5G” (http://sat5g-project.eu/) and Phase 3 project “5G-VINNI” (https://www.5g-vinni.eu/), on the European Space Agency ARTES project “SATis5” (https://artes.esa.int/projects/satis5), as well as on SES’s role in each of these initiatives.</p
MIMO Channels for next generation satellite networks
No full text279 σ.Αντικείμενο της Διατριβής είναι η έρευνα και ανάπτυξη μοντέλων για την περιγραφή ΜΙΜΟ δορυφορικών διαύλων με πολλαπλές εισόδους – πολλαπλές εξόδους και η εκτίμηση της επίδοσής τους μέσω αναλυτικών εκφράσεων και προσομοιώσεων.
Το Κεφάλαιο 1 παρέχει μια εισαγωγή στις πρόσφατες τεχνολογικές εξελίξεις των δορυφορικών επικοινωνιών και της τεχνολογίας MIMO και στη συνέχεια εισάγει την έννοια της εφαρμοσιμότητας της τεχνολογίας ΜΙΜΟ στις δορυφορικές επικοινωνίες. Στο Κεφάλαιο 2 αναλύονται τα φαινόμενα διάδοσης και οι αντίστοιχες διαλείψεις που χαρακτηρίζουν τους συμβατικούς SISO δορυφορικούς διαύλους με απλή είσοδο – απλή έξοδο και λειτουργούν σε συχνότητες τόσο κάτω όσο και άνω των 10GHz. Επίσης, αναλύεται προτεινόμενο αναλυτικό μοντέλο συσχέτισης των διαλείψεων λόγω βροχής και πολυδιαδρομικής διάδοσης σε SISO κινητό δορυφορικό δίαυλο σε συχνότητες άνω των 10GHz. Στο Κεφάλαιο 3 μελετώνται διάφοροι MIMO επίγειοι ασύρματοι δίαυλοι και εισάγονται θεμελιώδεις έννοιες που αφορούν τη χωρητικότητά τους με βάση τη θεωρία ΜΙΜΟ. Επίσης, αναλύεται η χωρητικότητα σε διάφορες ειδικές περιπτώσεις ΜΙΜΟ επίγειων ασυρμάτων διαύλων μεταξύ των οποίων και ο προτεινόμενος MIMO ασύρματος δίαυλος σε συχνότητες άνω των 10GHz υπό συνθήκες διαλείψεων λόγω βροχής.
Στη συνέχεια, ενοποιούνται οι αναλύσεις των Κεφαλαίων 2 και 3 για τη σε βάθος μελέτη εφαρμογής της τεχνολογίας MIMO στους δορυφορικούς διαύλους. Συγκεκριμένα, στο Κεφάλαιο 4 μελετώνται ΜΙΜΟ σταθεροί δορυφορικοί δίαυλοι που λειτουργούν σε συχνότητες άνω των 10GHz υπό συνθήκες διαλείψεων λόγω βροχής και στους οποίους εφαρμόζονται οι τεχνικές διαφορισμού δορυφόρου και διαφορισμού θέσης. Στο Κεφάλαιο 5 μελετώνται ΜΙΜΟ κινητοί δορυφορικοί δίαυλοι που λειτουργούν σε συχνότητες κάτω των 10GHz υπό συνθήκες διαλείψεων λόγω σκίασης και πολυδιαδρομικής διάδοσης και στους οποίους εφαρμόζονται οι τεχνικές διαφορισμού πόλωσης, διαφορισμού δορυφόρου και διαφορισμού κεραίας. Και στα δύο αυτά Κεφάλαια, έμφαση δίδεται στην έρευνα και ανάπτυξη μοντέλων για την αναλυτική περιγραφή των αντιστοίχων ΜΙΜΟ διαύλων και στην εκτίμηση της επίδοσής τους μέσω αναλυτικών εκφράσεων και προσομοιώσεων για τη χωρητικότητα διακοπής, την πιθανότητα διακοπής λόγω σφαλμάτων μετάδοσης ψηφίων και την πιθανότητα λάθους τους. Επιπλέον, στο Κεφάλαιο 5 δίδεται αναλυτική μεθοδολογία δημιουργίας χρονοσειρών των υπό μελέτη MIMO κινητών δορυφορικών διαύλων για την προσομοίωση επίδοσης των διαφόρων MIMO τεχνικών μετάδοσης σε σύγχρονα δορυφορικά συστήματα επικοινωνιών.This PhD Thesis deals with the research and development of MIMO satellite channel models and their performance improvement estimation through analytical expressions and computer simulations.
Chapter 1 provides an introduction on the recent technological advances in the fields of satellite communications and MIMO technology and then outlines issues associated to the applicability of MIMO technology to satellite channels. Chapter 2 analyzes the propagation impairments and the respective fading effects which characterize the conventional SISO satellite channels operating at frequencies below and above 10GHz. An analytical model on the relation between rain fading and multipath fading effects in SISO land mobile satellite (LMS) channels operating at frequencies above 10GHz is also proposed. Chapter 3 addresses MIMO terrestrial wireless communications and analyzes some fundamentals on channel modeling and capacity evaluation based on the available vast MIMO theory. The channel capacity is evaluated in several special cases of MIMO terrestrial wireless channels among which a proposed MIMO millimeter-wave channel which operates under rain fading.
The analyses of Chapters 2 and 3 are then unified in Chapters 4 and 5 for an in-depth investigation of MIMO applicability to satellite communications. Specifically, Chapter 4 deals with MIMO fixed satellite channels which operate at frequencies above 10GHz under rain fading and to which satellite diversity and site diversity are separately assumed for the MIMO channel matrix generation. Chapter 5 deals with MIMO LMS channels which operate at frequencies below 10GHz under shadowing and multipath fading and to which polarization diversity, satellite diversity and antenna diversity are separately assumed for the MIMO channel matrix generation. In both Chapters 4 and 5, emphasis is put on channel modeling and performance evaluation issues for the respective MIMO satellite channels through analytical expressions and computer simulations. In this regard, performance measures employed refer to outage capacity, bit error outage probability (BEOP) and bit error probability (BEP). Moreover, specifically, in Chapter 5, a step-by-step methodology for the time-series generation of the proposed MIMO LMS channels is provided for the performance assessment of advanced MIMO-enabled satellite transmission systems.Κωνσταντίνος Π. Λιώλη
Multi-Satellite MIMO Communications at Ku-Band and Above: Investigations on Spatial Multiplexing for Capacity Improvement and Selection Diversity for Interference Mitigation
No full textThis paper investigates the applicability of multiple-input multiple-output (MIMO) technology to satellite communications at the Ku-band and above. After introducing the possible diversity sources to form a MIMO matrix channel in a satellite environment, particular emphasis is put on satellite diversity. Two specific different topics from the field of MIMO technology applications to satellite communications at these frequencies are further analyzed: (i) capacity improvement achieved by MIMO spatial multiplexing systems and (ii) interference mitigation achieved by MIMO diversity systems employing receive antenna selection. In the first case, a single-user capacity analysis of a satellite 2×2 MIMO spatial multiplexing system is presented and a useful analytical closed form expression is derived for the outage capacity achieved. In the second case, a satellite 2×2 MIMO diversity system with receive antenna selection is considered, adjacent satellite cochannel interference on its forward link is studied and an analytical model predicting the interference mitigation achieved is presented. In both cases, an appropriate physical MIMO channel model is assumed which takes into account the propagation phenomena related to the frequencies of interest, such as clear line-of-sight operation, high antenna directivity, the effect of rain fading, and the slant path lengths difference. Useful numerical results obtained through the analytical expressions derived are presented to compare the performance of multi-satellite MIMO systems to relevant single-input single-output (SISO) ones
<i>SPELL-fuzz</i> : An Innovative Tool for Fully Automated Verification of SPELL Satellite Operation Procedures
No full textNext-Generation MIMO Satellite Systems From Channel Modeling to System Performance Evaluation
No full textMulti-Satellite MIMO Communications at Ku-Band and Above: Investigations on Spatial Multiplexing for Capacity Improvement and Selection Diversity for Interference Mitigation
No full text This paper investigates the applicability of multiple-input multiple-output (MIMO) technology to satellite communications at the Ku-band and above. After introducing the possible diversity sources to form a MIMO matrix channel in a satellite environment, particular emphasis is put on satellite diversity. Two specific different topics from the field of MIMO technology applications to satellite communications at these frequencies are further analyzed: (i) capacity improvement achieved by MIMO spatial multiplexing systems and (ii) interference mitigation achieved by MIMO diversity systems employing receive antenna selection. In the first case, a single-user capacity analysis of a satellite MIMO spatial multiplexing system is presented and a useful analytical closed form expression is derived for the outage capacity achieved. In the second case, a satellite MIMO diversity system with receive antenna selection is considered, adjacent satellite cochannel interference on its forward link is studied and an analytical model predicting the interference mitigation achieved is presented. In both cases, an appropriate physical MIMO channel model is assumed which takes into account the propagation phenomena related to the frequencies of interest, such as clear line-of-sight operation, high antenna directivity, the effect of rain fading, and the slant path lengths difference. Useful numerical results obtained through the analytical expressions derived are presented to compare the performance of multi-satellite MIMO systems to relevant single-input single-output (SISO) ones.</p
Railway satellite channel at Ku band and above: Composite dynamic modeling for the design of fade mitigation techniques
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On statistical modeling and performance evaluation of SIMO land mobile satellite channels
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