Statistical Characterization of RIS-assisted UAV Communications in Terrestrial and Non-Terrestrial Networks Under Channel Aging

This paper studies the statistical characterization of ground-to-air (G2A) and reconfigurable intelligent surface (RIS)-assisted air-to-ground (A2G) communications with unmanned aerial vehicles (UAVs) in terrestrial and non-terrestrial networks under the impact of channel aging. We first model the G2A and A2G signal-to-noise ratios (SNRs) as non-central complex Gaussian quadratic random variables (RVs) and derive their exact probability density functions, offering a unique characterization for the A2G SNR as the product of two scaled non-central chi-square RVs. Moreover, we also find that, for a large number of RIS elements, the RIS-assisted A2G channel can be characterized as a single Rician fading channel. Our results reveal the presence of channel hardening in A2G communication under low UAV speeds, where we derive the maximum target spectral efficiency (SE) for a system to maintain a consistent required outage level. Meanwhile, high UAV speeds, exceeding 50 m/s, lead to a significant performance degradation, which cannot be mitigated by increasing the number of RIS elements.Comment: 6 pages, 3 figures and 7 subfigures, IEEE ICC'24 (Revision

Agile 5G Scheduler for Improved E2E Performance and Flexibility for Different Network Implementations

In this article, we present a holistic overview of the agile multi-user scheduling functionality in 5G. An E2E perspective is given, including the enhanced QoS architecture that comes with 5G, and the large number of scheduling relatedoptions from the new access stratum sub-layer, MAC, and PHY layer. A survey of the 5G design agreements from the recently concluded 5G Study in 3GPP is presented, and it is explained how to best utilize all these new degrees of freedom to arrive at an agile scheduling design that offers superior E2E performance for a variety of services with highly diverse QoS requirements.Enhancements to ensure efficient implementation of the 5G scheduler for different Network architectures are outlined. Finally, state-of-the-art system level performance results are presented, showing the ability to efficiently multiplex services with highly diverse QoS requirements.In this article, we present a holistic overview of the agile multi-user scheduling functionality in 5G. An E2E perspective is given, including the enhanced QoS architecture that comes with 5G, and the large number of scheduling related options from the new access stratum sub-layer, MAC, and PHY layer. A survey of the 5G design agreements from the recently concluded 5G Study in 3GPP is presented, and it is explained how to best utilize all these new degrees of freedom to arrive at an agile scheduling design that offers superior E2E performance for a variety of services with highly diverse QoS requirements. Enhancements to ensure efficient implementation of the 5G scheduler for different network architectures are outlined. Finally, state-of-the-art system level performance results are presented, showing the ability to efficiently multiplex services with highly diverse QoS requirements

New forms of electronic media and their impact on public policy making: three cases from Egypt

There is an increasing rise in the popularity of electronic media, especially Facebook and YouTube in the Arab world, and in Egypt in particular. This reflects an important indication of the growing influence of Facebook and YouTube on the Egyptian society and on Egypt\u27s political stream. The purpose of this study is to answer the main research question, which is to what extent does electronic media affect public policy making in Egypt, with regards to three cases studies. They include the Egyptian/Algerian football conflict, as a result of a soccer match qualifying the winning team to the World Cup 2010, the face-veil controversy, banning women wearing the face-veil to enter public university examinations, and the Fair Access Policy limiting Internet download for DSL and ADSL subscribers. The objective is to determine whether electronic media has the power to mobilize public opinion towards a certain cause, which may then affect government action. This would allow us to realize first the power and influence of mainstream media, followed by electronic media, and the factors that affect Egypt\u27s policy making decisions. The methodology adopted in this study include a review of literature, a qualitative study, that includes interviews with media and political science experts, and a quantitative study surveying 238 students from The American University in Cairo and Cairo University. Respondents for the in-depth interviews were selected based on their professional expertise, and the respondents for the survey were based on a non-probability convenient sample from The American University in Cairo and Cairo University students, which represent a sample of Egyptian youth coming from different socio-economic backgrounds. The study findings indicate that electronic media affects public policy making decisions to a certain extent and on a case by case basis. Although Egypt is a non-democratic country, whose policies do not get affected easily by public opinion, the mobilization of educated youth through online social networks, such as Facebook and YouTube, are growing in influence and are having an impact on Egypt\u27s political stream. The findings of the study reveal that the government is paying attention to online social networks, which is indicated from the arrests of online political activists and bloggers, and its response to the public outcry on the Egyptian/Algerian football conflict. There is also evidence that the mobilization of Internet users through Facebook groups is linked to the government\u27s decision to reverse the Fair Access Policy two weeks after it was announced. As for the face-veil controversy, online discussions are affecting public opinion and public debate, however, there is no direct link on the court decision to ban or allow women wearing the face-veil to enter public university examinations

An SDN QoE Monitoring Framework for VoIP and video applications

Τα τελευταία χρόνια έχει σημειωθεί ραγδαία άνοδος του κλάδου των κινητών επικοινωνιών, αφού η χρήση των κινητών συσκευών εξαπλώνεται με ταχύτατους ρυθμούς και αναμένεται να συνεχίσει τη διείσδυσή της στην καθημερινότητα των καταναλωτών. Το γεγονός αυτό, σε συνδυασμό με τους περιορισμούς που θέτει η τρέχουσα δομή των δικτύων επικοινωνιών, καθιστά αναγκαία την ανάπτυξη νέων δικτύων με αυξημένες δυνατότητες, ώστε να είναι δυνατή η εξυπηρέτηση των χρηστών με την καλύτερη δυνατή ποιότητα εμπειρίας και ταυτόχρονα τη βέλτιστη αξιοποίηση των πόρων του δικτύου. Μία νέα δικτυακή προσέγγιση αποτελεί η δικτύωση βασισμένη στο λογισμικό (Software Defined Networking - SDN), η οποία αφαιρεί τον έλεγχο από τις συσκευές προώθησης του δικτύου, και οι αποφάσεις λαμβάνονται σε κεντρικό σημείο. Η ποιότητα υπηρεσίας που αντιλαμβάνεται ο χρήστης, ή αλλιώς ποιότητα εμπειρίας, κρίνεται ζήτημα υψηλής σημασίας στα δίκτυα SDN. Η παρούσα διπλωματική εργασία έχει ως στόχο την παρουσίαση της τεχνολογίας SDN, την επισκόπηση της υπάρχουσας έρευνας στο πεδίο της ποιότητας εμπειρίας σε SDN δίκτυα και στη συνέχεια την ανάπτυξη μίας SDN εφαρμογής η οποία παρακολουθεί και διατηρεί την ποιότητας εμπειρίας σε υψηλά επίπεδα για εφαρμογές VoIP και video. Πιο συγκεκριμένα, η εφαρμογή SQMF (SDN QoE Monitoring Framework) παρακολουθεί περιοδικά στο μονοπάτι μετάδοσης των πακέτων διάφορες παραμέτρους του δικτύου, με βάση τις οποίες υπολογίζει την ποιότητα εμπειρίας. Εάν διαπιστωθεί ότι το αποτέλεσμα είναι μικρότερο από ένα προσδιορισμένο κατώφλι, η εφαρμογή αλλάζει το μονοπάτι μετάδοσης, και έτσι η ποιότητα εμπειρίας ανακάμπτει. Η δομή της παρούσας διπλωματικής εργασίας είναι η εξής: Στο κεφάλαιο 1 παρουσιάζεται η σημερινή εικόνα των δικτύων επικοινωνιών και οι προβλέψεις για τη μελλοντική εικόνα, καθώς και οι προκλήσεις στις οποίες τα σημερινά δίκτυα δε θα μπορούν να αντεπεξέλθουν. Στη συνέχεια στο κεφάλαιο 2 περιγράφεται αναλυτικά η τεχνολογία SDN ως προς την αρχιτεκτονική, το κύριο πρωτόκολλο που χρησιμοποιεί, τα σενάρια χρήσης της, την προτυποποίηση, τα πλεονεκτήματα και τα μειονεκτήματά της. Το κεφάλαιο 3 εισάγει την έννοια της ποιότητας εμπειρίας του χρήστη και παραθέτει ευρέως γνωστά μοντέλα υπολογισμού της για διάφορους τύπους εφαρμογών, που χρησιμοποιούνται στην παρούσα εργασία. Σχετικές υπάρχουσες μελέτες στο πεδίο της ποιότητας εμπειρίας σε δίκτυα SDN αλλά και συγκριτικός πίνακας μπορούν να βρεθούν στο κεφάλαιο 4. Τα επόμενα κεφάλαια αφορούν στην εφαρμογή SQMF που υλοποιήθηκε στα πλαίσια της παρούσας διπλωματικής εργασίας: το κεφάλαιο 5 περιγράφει αναλυτικά όλα τα προαπαιτούμενα εργαλεία και οδηγίες για την ανάπτυξη του SQMF, ενώ το κεφάλαιο 6 παρουσιάζει παραδείγματα όπου η ποιότητα εμπειρίας ενός δικτύου μπορεί να υποστεί μείωση. Τέλος, το κεφάλαιο 7 αναλύει σε βάθος τις σχεδιαστικές προδιαγραφές, τη λογική και τον κώδικα του SQMF και παρέχει επίδειξη της λειτουργίας του και αξιολόγησή του, ενώ το κεφάλαιο 8 συνοψίζει επιγραμματικά τα συμπεράσματα της παρούσας εργασίας και ανοιχτά θέματα για μελλοντική έρευνα.Lately, there has been a rapid rise of the mobile communications industry, since the use of mobile devices is spreading at a fast pace and is expected to continue its penetration into the daily routine of consumers. This fact, combined with the limitations of the current communications networks’ structure, necessitates the development of new networks with increased capabilities, so that users can be served with the best possible quality of service and at the same time with the optimal network resources utilization. A new networking approach is Software Defined Networking (SDN) which decouples the control from the data plane, transforming the network elements to simple forwarding devices and making decisions centrally. The quality of service perceived by the user, or quality of experience (QoE), is considered to be a matter of great importance in software defined networks. This diploma thesis aims at presenting SDN technology, reviewing existing research in the field of QoE on SDN networks and then developing an SDN application that monitors and preserves the QoE for VoIP and video applications. More specifically, the developed SDN QoE Monitoring Framework (SQMF) periodically monitors various network parameters on the VoIP/video packets transmission path, based on which it calculates the QoE. If it is found that the result is less than a predefined threshold, the framework changes the transmission path, and thus the QoE recovers. The structure of this diploma thesis is the following: Chapter 1 presents the current state of communications networks and predictions for the future state, as well as the challenges that current networks will not be able to cope with. Chapter 2 then describes in detail the SDN technology in terms of architecture, main control-data plane communication protocol, use cases, standardization, advantages and disadvantages. Chapter 3 introduces the concept of QoE and lists well-known QoE estimation models for various applications types, some of which were used in this thesis. Relevant existing studies in the field of QoE on SDN networks as well as a comparative table can be found in chapter 4. The following chapters concern the framework implemented in the context of this diploma thesis: Chapter 5 describes in detail all the required tools and instructions for the development of SQMF, while Chapter 6 presents examples where the QoE in a network can face degradation. Finally, Chapter 7 analyzes in depth SQMF's design principles, logic and code files, provides a demonstration of its operation and evaluates it, whereas Chapter 8 briefly summarizes the conclusions and of this thesis and future work points

Human-Machinic Assemblages: Technologies, Bodies, and the Recuperation of Social Reproduction in the Crisis Era

This dissertation argues that class composition, as defined and theorised by Operaismo and Autonomist thinkers, has had both a major and a minoritarian form. In fact class composition in its major form has always been subtended by a minor current. I examine both historical (the 1905 Russian Soviets, the 1919 Turin factory councils, the Italian social movements of the 1970s) and contemporary examples (the occupation of Tahrir Square in Egypt, the Indignados movement in Spain, and Occupy Wall Street in 2011, as well as the 2012 Quebec student strike) of class composition. From these examples I then argue that the minor current of class composition is rooted in social reproduction – both its crisis and its recuperation. And further that this minor current expands throughout history, growing to command greater attention within social and labour movements. Further, this dissertation argues that contemporary social movements appear today as an assemblage, a human-machinic assemblage, which enact social reproduction in crisis and recuperation through both embodied and technologized forms. I demonstrate the ways in which technologies of communication are implicated in forms of securitised and commodified social reproduction, but also open up new and powerful possibilities for autonomous and liberatory social reproduction. This dissertation relies on a merger of conceptual, theoretical, and field research and benefits from the author’s direct involvement in social and political struggles

Διαμοιρασμός Πόρων ως Υπηρεσία : Τεχνικές Προκλήσεις και Λύσεις για Ασύρματα Δίκτυα Πέμπτης Γενιάς

Η αναμενόμενη «έκρηξη» στην κίνηση δεδομένων που προέρχονται από ασύρματα δίκτυα επικοινωνιών, σε συνδυασμό με τη μετάβαση σε έναν «ΙοΤ κόσμο», καθιστά αναγκαία την ανάπτυξη μίας νέας γενιάς δικτύων προκειμένου να ικανοποιηθούν οι ολοένα αναδυόμενες ανάγκες των χρηστών. Το όραμα για τα δίκτυα 5ης γενιάς (5G) θέτει στο επίκεντρο του ενδιαφέροντος την ικανοποίηση τριών βασικών απαιτήσεων: την επίτευξη της μέγιστης δυνατής ρυθμοαπόδοσης (throughput), την επίτευξη της ελάχιστης δυνατής καθυστέρησης (latency) και την παράλληλη εξυπηρέτηση μεγάλου όγκου συνδέσεων. Στην ικανοποίηση των εν λόγω απαιτήσεων διαδραματίζουν σημαντικό ρόλο η προτυποποίηση, η αρχιτεκτονική και οι τεχνολογίες δικτύου που θα υιοθετηθούν στα νέα συστήματα κινητών επικοινωνιών. Ωστόσο, παράλληλα σημαντικό παράγοντα αποτελεί η αναγνώριση των αδυναμιών που φέρουν τα συστήματα προηγούμενων γενεών και η αποτελεσματική αντιμετώπιση τους. Το πρόβλημα των αναξιοποίητων δικτυακών πόρων έχει αναγνωριστεί από την επιστημονική κοινότητα και ήδη μελετώνται προτάσεις για την διευθέτησή του. Στα πλαίσια της παρούσας εργασίας πραγματοποιείται μία εκτενής επισκόπηση των συστημάτων κινητών επικοινωνιών 5ης γενιάς (5G), ενώ στην πορεία μελετάται το ζήτημα της αποτελεσματικής κατανομής δικτυακών πόρων και προτείνεται ένα νέο πρωτόκολλο για τη διευθέτηση του. Πιο συγκεκριμένα, αρχικά μελετώνται τα κίνητρα ανάπτυξης των 5G δικτύων, η πορεία προς την προτυποποίηση τους και οι απαιτήσεις που τίθενται. Επιπρόσθετα, πραγματοποιείται περιγραφή των ενδεχόμενων σεναρίων αρχιτεκτονικής, καθώς επίσης και των επικρατέστερων τεχνολογιών για την υποστήριξης της. Το κομμάτι της επισκόπησης της νέας γενιάς δικτύων ολοκληρώνεται με μία σύντομη αναφορά στα χρηματοδοτούμενα από την Ευρωπαϊκή Ένωση ερευνητικά προγράμματα που έχουν ως στόχο την διερεύνηση σχετικών λύσεων για τα επερχόμενα συστήματα. Στη συνέχεια τίθεται στο προσκήνιο το πρόβλημα ύπαρξης αναξιοποίητων ράδιο-πόρων και αναγνωρίζεται η ανάγκη για το διαμοιρασμό τους μεταξύ διαφορετικών παρόχων. Αφού γίνει μία σύντομη αναφορά σε υπάρχουσες σχετικές μελέτες, παρουσιάζεται εκτενώς το πρωτόκολλο «Διαμοιρασμού ράδιο-πόρων με Network-Centric προσέγγιση», το οποίο θέτει το τεχνολογικό υπόβαθρο για το πρωτόκολλο που προτείνεται μέσω της παρούσας εργασίας. Πιο συγκεκριμένα, προτείνεται μία εναλλακτική σχεδίαση για το προαναφερθέν πρωτόκολλο, η οποία φέρει τον τίτλο «Διαμοιρασμός ράδιο-πόρων με Device-Centric προσέγγιση». Αφού πραγματοποιηθεί εκτενής παρουσίαση του προτεινόμενου πρωτοκόλλου, λαμβάνει χώρα μία σύγκριση μεταξύ της Network-Centric και Device-Centric προσέγγισης. Στη συνέχεια, αναγνωρίζονται οι πτυχές του θέματος διαμοιρασμού των ράδιο-πόρων που χρήζουν περαιτέρω επιστημονικής μελέτης. Τέλος, πραγματοποιείται προσομοίωση δικτύουThe expected explosive increase in demand for wireless broadband services in combination with the Internet of Things (IoT) society, necessitates the development of a new network generation to meet the ever-emerging user needs. The 5th generation (5G) networks vision places under the spotlight three basic requirements that have to be met: the maximum possible throughput, the minimum possible latency and the support of massive device connectivity. Standardization, network architecture and network technologies play an important role in satisfying the aforementioned requirements. However, it is essential to identify the weaknesses of the previous generation systems and cope with them by proceeding with all the necessary improvements. The problem of unused network resources has been detected by the scientific community and there are already some proposals for tackling it. As part of this thesis, an extensive review of the 5th generation mobile communications systems (5G) is carried out, while the issue of the efficient network resources allocation follows along with a new protocol proposal for its addressing. More specifically, the motivation for the 5G systems development, the standardization timeline and the requirements posed are first studied. Moreover, some possible architecture scenarios and the technologies that aim to be used in order to support them are examined as well. At the end of this review, we proceed with presenting the projects funded by the European Union for research in the 5G development filed. Subsequently, the problem of unused radio resources is set in the spotlight and the need for radio resource sharing between different network operators is pointed out. Having presented some relevant studies, we analyze the “Radio Resource Sharing with Network-Centric Approach” protocol, which sets the technical base and the idea of the new protocol that we introduce through this thesis. More specifically, an alternative approach regarding the aforementioned protocol is the “Radio Resource Sharing with Device-Centric Approach”. After an extensive presentation of the new proposed protocol, a comparative analysis between Network-Centric and Device-Centric approaches takes place. Then, the radio resource sharing aspects that need further investigation and scientific research in the future are recognized. We end up with a network simulation based on the prosed protocol usage and proceed with a result analysi

Watching the Watchers: New Perspectives on Spectatorship, Gaming and Online Media

Electronic sports (e-sports) represents the configuration of competitive videogaming as spectatorial, professionalized sport, problematizing conventional distinctions between work and leisure, ‘geek’ and ‘jock’ cultures, and crucially, between playing games and watching others play. Much of the scholarship on e-sports has focused primarily on players and player communities involved in the ‘professionalization’ of digital gaming, examining players’ game-based skillsets (Rambusch, Jakobsson & Pargman, 2007), the ways they negotiate the rules, expectations and challenges that come with professional play (Witkowski, 2012), and the formation of gendered subjectivities afforded (and constrained) by the confluence of gaming and sport (Taylor, 2010). Recent work by TL Taylor (2012) and Todd Harper (2010) have begun to extend the study of competitive play beyond players, examining the fundamental role of spectatorship in the social, technological and economic development of e-sports. As TL Taylor points out in Raising the Stakes, the connections between spectatorship and play run deep. While The Wizard, Twin Galaxies, and Starcade may have presented spectatorial gaming as an entertaining, if quirky sideshow, watching others play - whether attending tournaments, bars or arcades in person, or simply watching others in between turns at the controls - has arguably always been an integral, albeit understudied, part of gaming culture (Alloway & Gilbert, 1998; Lin & Sun, 2011; Taylor, 2012). Over the last 15 years, however, the loosely affiliated and often volatile assortment of clans, tournaments and leagues collectively representing the e-sports industry has sought to cultivate a mass online audience for competitive, elite gaming. Recent developments have demonstrated that there is indeed a global audience for e-sports, made possible both by the surging popularity of specific games as well as by the emergence of high definition, live streaming webcasts, and the various viewer practices and business models these make possible. Major League Gaming (MLG), the self-proclaimed “world’s largest e-sports organization”, recently reported 11.7 million “live online viewers” for online, streaming webcasts of MLG’s Pro Circuit tournament play in 2012 (MLG, 2012). The last day of competition of the 2012 Spring Championship, held June 8-10 in Anaheim, CA, which featured the League of Legends and Starcraft 2 finals, drew 2.2 million viewers to MLG’s webcast – more than their total number of unique viewers for all 2010. Over roughly the same period of time, Twitch (http://www.twitch.tv/) has emerged as a highly popular venue to watch live-streaming videogame play, including e-sports. Boasting over 23 million subscribers a month, the platform has not only offered a means for e-sports organizations, teams and individual players to reach potentially massive audiences, but it has served to further enact and legitimate the notion of gaming as something we watch as well as something we do. The recent success of MLG and Twitch, as well as the (related) surging popularity of Starcraft 2 and League of Legends, have seemed to establish e-sports as a legitimate and viable entertainment media industry (Tassi, 2013). At the same time, the short history of professional gaming is marked as much by sudden declines as by sudden success; claims that ‘e-sports has finally arrived’ were heard shortly before the collapse of the longstanding Cyberathlete Professional League (CPL) and the much-touted Championship Gaming Series (CGS) in 2008-2009, for instance (Kane, 2010). Outside of South Korea, where e-sports has had a solid foothold for some time (Jin, 2010), competitive gaming organizations struggle to attract and maintain sponsorship for what is still largely seen, by potential sponsors, as a marketing experiment (Taylor, 2012, p. 146). Adding to this the high “churn” rate of players, games, and tournaments (p. 153); the brevity of players’ careers and the relatively short shelf life of games and gaming platforms means that the constellation of pro-gaming ‘stars’ shifts rapidly. For these reasons, competitive gaming is very much a moving target for researchers: often, by the time a particular community, tournament, or organization is reported on in academic publications, it no longer exists in the same form, if at all. Given this dynamic and unpredictable terrain, one of the central challenges for e-sports researchers is to link accounts of competitive gaming to larger transformations in digital games, social media, and emerging forms of both leisure and labor. Each of the papers on this panel undertakes this project, whether through linking e-sports spectatorship in China to issues of censorship, nationality, and broadcasting, analyzing the fundamental role of spectators in enacting and shaping the psychological and social experiences of play, or exploring changes in the ways spectators have been incorporated into the ‘assemblage’ of North American e-sports broadcasting over the past five years. Collectively, this panel represents an attempt to more productively understand the crucial role that audiences carry out in the ongoing socio-technical transformation of digital play as spectatorial activity