A REVIEW STUDY OF EUROPEAN R&D PROJECTS FOR SATELLITE COMMUNICATIONS IN 5G/6G ERA

Κατά τις τελευταίες δεκαετίες τα δορυφορικά συστήματα τηλεπικοινωνιών έχουν προσφέρει μια γκάμα από πολυμεσικές υπηρεσίες όπως δορυφορική τηλεόραση, δορυφορική τηλεφωνία και ευρυζωνική πρόσβαση στο διαδίκτυο. Οι μακροπρόθεσμες τεχνολογικές αναβαθμίσεις σε συνδυασμό με την προσθήκη νέων δορυφορικών συστημάτων γεωστατικής και ελλειπτικής τροχιάς και με την ενσωμάτωση τεχνολογιών πληροφορικής έχουν ωθήσει την αύξηση του μέγιστου εύρους των δορυφόρων στο 1Gbps σε μεμονωμένους δορυφόρους ενώ σε διάταξη αστερισμού μπορούν να ξεπεράσουν το 1 Tbps. Σε συνδυασμό με την μείωση του χρόνου απόκρισης σε ρυθμούς ανταγωνιστικούς με τις χερσαίες υποδομές ανοίγουν νέες ευκαιρίες και νέους ρόλους εντός ενός οικοσυστήματος ετερογενούς δικτύων 5ης γενιάς. Σε αυτήν την διατριβή, αξιολογούμε επιδοτούμενα επιστημονικά προγράμματα έρευνας και ανάπτυξης της Ευρωπαϊκής Επιτροπής Διαστήματος (ESA) και του προγράμματος επιδότησης Horizon 2020 της Ευρωπαϊκής Ένωσης, προκειμένου να εξηγήσουμε τις δυνατότητες των δορυφόρων εντός ενός ετερογενούς δικτύου 5ης γενιάς, αναφέρουμε συγκεκριμένα αυτά που αφορούν την εξέλιξη των δορυφορικών ψηφιακών συστημάτων και την ικανότητα ενσωμάτωσης τους σε τωρινές αλλά και μελλοντικές υποδομές χερσαίων τηλεπικοινωνιακών δικτύων μέσω της εμφάνισης νέων τεχνολογιών στις ηλεκτρονικές και οπτικές επικοινωνίες αέρος μαζί με την εμφάνιση τεχνολογιών πληροφορικής όπως της δικτύωσης βασισμένης στο λογισμικό και της εικονικοποίησης λειτουργιών δικτύου. Αναφερόμαστε στους στόχους του κάθε project ξεχωριστά και κατηγοριοποιημένα στους ακόλουθους τομείς έρευνας: -Συσσωμάτωση των δορυφόρων με τα επίγεια δίκτυα 5ης γενιάς με οργανωμένες μελέτες και στρατηγικές -Ενσωμάτωση των τεχνολογιών δικτύωσης βασισμένης στο λογισμικό και εικονικοποίησης λειτουργιών δικτύου στο δορυφορικών τμήμα των δικτύων 5ης γενιάς -Ο ρόλος των δορυφόρων σε εφαρμογές του διαδικτύου των πραγμάτων σε συνάφεια με τα χερσαία δίκτυα 5ης γενιάς -Ο ρόλος των δορυφόρων στην δίκτυα διανομής πολυμεσικού περιεχομένου & η επιρροή των πρωτοκόλλων διαδικτύου στην ποιότητα υπηρεσίας χρήστη κατά την διάρκεια μιας δορυφορικής σύνδεσης. -Μελλοντικές βελτιώσεις και εφαρμογές στα δορυφορικά συστήματα με έμφαση στα μελλοντικά πρότυπα του φυσικό επιπέδου Στο τέλος διαθέτουμε ένα παράρτημα που αφορά τεχνικές αναλύσεις στην εξέλιξη του φυσικού επιπέδου των δορυφορικών συστημάτων, συνοδευόμενο με την συσχετιζόμενη βιβλιογραφία για περαιτέρω μελέτη.Over the last decades satellite telecommunication systems offer many types of multimedia services like Satellite TV, telephony and broadband internet access. The long-term technological evolutions occurred into state-of-the-art satellite systems altogether with the addition of new high throughput geostatic and non-geostatic systems, individual satellites can now achieve a peak bandwidth of up to Gbps, and with possible extension into satellite constellation systems the total capacity can reach up to Tbps. Supplementary, with systems latency being comparable to terrestrial infrastructures and with integration of several computer science technologies, satellite systems can achieve new & more advanced roles inside a heterogeneous 5G network’s ecosystem. In this thesis, we have studied European Space Agency (ESA’s) and European Union’s (EU) Horizon 2020 Research and Development (R&D) funded projects in order to describe the satellite capabilities within a 5G heterogeneous network, mentioning the impact of the evolution of digital satellite communications and furthermore the integration with the state-of the art & future terrain telecommunication systems by new technologies occurred through the evolution of electronic & free space optical communications alongside with the integration of computer science’s technologies like Software Defined Networking (SDN) and Network Function Virtualization (NFV). In order to describe this evolution we have studied the concepts of each individual project, categorized chronically and individual by its scientific field of research. Our main scientific trends for this thesis are: -Satellite Integration studies & strategies into the 5G terrestrial networks -Integration of SDN and NFV technologies on 5G satellite component -Satellite’s role in the Internet of Things applications over 5G terrestrial networks -Satellite’s role in Content Distribution Networks & internet protocols impact over user’s Quality of Experience (QoE) over a satellite link -The future proposals upon the evolution of Satellite systems by upcoming improvements and corresponding standards Finally, we have created an Annex for technical details upon the evolution of physical layer of the satellite systems with the corresponding bibliography of this thesis for future study

Um arcabouço holístico para a execução de funções virtualizadas de rede : arquitetura, gerenciamento e aplicações

Orientador: Elias Procópio Duarte JúniorTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa : Curitiba, 16/12/2022Inclui referênciasÁrea de concentração: Ciência da ComputaçãoResumo: O paradigma de Virtualização de Funções de Rede (Network Function Virtualization - NFV) visa desacoplar as funções de rede de hardware dedicado, utilizando tecnologias de virtualização para implementar as funções em software. A arquitetura de referência NFV tem sido amplamente adotada, sendo esta composta por três domínios: Infraestrutura Virtualizada (Virtualized Infrastructure - VI), Gerenciamento e Orquestração de NFV (NFV Management and Orchestration - NFV-MANO), além das próprias Funções Virtualizadas de Rede (Virtualized Network Functions - VNF). Já serviços virtualizados são definidos como composições de funções virtualizadas, organizados através de topologias que estabelecem o fluxo de processamento do tráfego de rede. Apesar do grande potencial do paradigma NFV, ainda existem importantes desafios para garantir que seja amplamente adotado nas infraestruturas modernas de telecomunicação. Esta Tese tem como objetivo principal contribuir para a gerência do ciclo de vida de funções e serviços virtualizados de rede. Neste sentido assume-se a premissa de que é essencial garantir previsibilidade operacional e padronização dos elementos que atuam no domínio de VNF, i.e., das plataformas de execução de VNF e dos Sistemas de Gerenciamento de Elemento (Element Management System - EMS). São propostas na Tese arquiteturas que descrevem um modelo de execução e gerenciamento padronizado tanto para plataformas de execução de VNF, como para o EMS, compatíveis com a arquitetura de referência NFV-MANO. As arquiteturas propostas preveem protocolos, interfaces de comunicação e orientações de integração com demais elementos e sistemas NFV. Ambas as arquiteturas foram implementadas e estão disponíveis como software livre: a plataforma COVEN de execução de VNF e o EMS HoLMES. Resultados de avaliação experimental e estudos de caso são apresentados e discutidos. Também, uma investigação do impacto das arquiteturas propostas em três contextos distintos é então introduzida. Inicialmente, é explorado seu impacto como facilitador para a gerência de NFV. Em seguida, o foco fica no compartilhamento de instâncias de funções e serviços de rede, e na emulação NFV. A Tese apresenta também contribuições no contexto de serviços virtualizados de rede. Em particular, o mapeamento multidomínio consiste na implantação de serviços em infraestruturas de virtualização distribuídas. Assim, foi proposta uma estratégia de mapeamento baseado em heurísticas genéticas, denominada GeSeMa. A estratégia permite que seus operadores definam diferentes critérios de avaliação e otimização em busca de mapeamentos de serviço adequados às suas necessidades específicas. Neste sentido, o GeSeMa representa um avanço do estado da arte, pois outras soluções operam de maneira monolítica, não permitindo que operadores e gerentes de rede personalizem o esquema de otimização adotado (e.g., métricas a serem avaliadas, pesos a serem considerados e restrições de mapeamento relacionadas a cada serviço em particular). A solução foi testada em múltiplos estudos de caso e os resultados demonstram sua aplicabilidade e ?exibilidade ao lidar com diferentes cenários de otimização de mapeamentos multidomínio. Finalmente, outras duas contribuições da Tese relacionadas ao paradigma NFV são apresentadas como apêndices, nos contextos de tolerância a falhas e engenharia de tráfego.Abstract: The Network Function Virtualization (NFV) paradigm aims to decouple network functions from dedicated hardware, employing virtualization technologies to implement functions in software. The NFV reference architecture has been widely adopted. This architecture, in turn, is composed of three domains: Virtualized Infrastructure (VI), NFV Management and Orchestration (NFV-MANO), and Virtualized Network Functions (VNF). Compositions of virtualized functions define virtualized services, organized as topologies through which network trafic is steered. Despite the extraordinary potential of the NFV paradigm, there are still relevant challenges to ensure its wide adoption by modern telecommunication infrastructures. The main objective of this Thesis is to contribute to the life cycle management of virtualized network functions and services. In this context, we consider it essential to guarantee the operational predictability and organization of the elements of the VNF domain, i.e., VNF execution platforms, and the Element Management System (EMS). Thus, this Thesis presents architectures that describe a standardized execution and management model for both VNF execution platforms and EMS. The proposed architectures are compliant with the NFV-MANO reference architecture and provide protocols, communication interfaces, and guidelines for their integration with other NFV elements and systems. Both architectures have been implemented and are available as open-source software: the COVEN VNF execution platform and the HoLMES EMS. Experimental evaluation results and case studies are presented and discussed. An investigation of the impact of the proposed architectures in three di?erent contexts is also introduced. First, we explore the opportunities regarding the proposed architectures as enablers for NFV management. Then, the focus goes to sharing instances of network functions and services and NFV emulation. In addition, the Thesis presents contributions in the context of virtualized network services. Multidomain mapping consists of deploying services on distributed virtualization infrastructures. A mapping strategy based on genetic heuristics, called GeSeMa, was proposed. GeSeMa enables its operators to define multiple optimization criteria for searching candidate service mappings tailored to their specific requirements. The proposed strategy represents a state-of-the-art advance, as other solutions operate in a monolithic manner: they do not allow operators and network managers to customize the adopted evaluation setup (e.g., metrics to be evaluated, weights to be considered, and mapping constraints related to each specific service). We tested GeSeMa in multiple case studies; the results demonstrate its applicability and flexibility in dealing with different multidomain mapping optimization scenarios. Finally, two other contributions related to the NFV paradigm, approaching fault tolerance and trafic engineering, are presented as appendices