174 research outputs found

    Final report on the evaluation of RRM/CRRM algorithms

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    Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin

    QoE estimation for Adaptive Video Streaming over LTE Networks

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    Η 4η γενιά (4G) κινητών επικοινωνιών, στην οποία ανήκει το σύστημα Long Term Evolution (LTE), παρέχει ευρυζωνική πρόσβαση σε κινητές συσκευές με ποιότητα και ταχύτητα που αγγίζουν τις ενσύρματες επικοινωνίες. Παρόλ’αυτά, η κινητικότητα εκ φύσεως εισάγει αστοχίες/διακυμάνσεις στην ασύρματη διεπαφή, γενόντας έτσι την ανάγκη για αντίστοιχη προσαρμογή της ροής μετάδοσης των δεδομένων. Η ανάγκη αυτή είναι ακόμη πιο έκδηλη για τις ροές δεδομένων βίντεο, που έχουν και τη μερίδα του λέοντος στην διαδικτυακή κίνηση. Καθώς, λοιπόν, η ροή βίντεο μέσω ΗΤΤΡ έχει γίνει ο κανόνας στη διανομήπεριεχομένου, η εφαρμογή ενός πρωτοκόλλου προσαρμογής βασισμένου στο HTTP είναι αναπόφευκτη. Το DASH (Dynamic Adaptive Streaming over HTTP) επιτρέπει μια ομαλή, αδιάκοπη ροή video εφαρμόζοντας αλγόριθμους προσαρμογής του bitrate στη μεριά του χρήστη αξιοποιώντας πλήρως την υπάρχουσα υποδομή. Έχοντας ως στόχο να τελειοποιήσουν την ποιότητα την οποία προσφέρει στους χρήστες το δίκτυο, οι ερευνητές συνεχώς αναπτύσσουν νέες φόρμουλες για την εκτίμηση της ποιότητας εμπειρίας του τελικού χρήστη, γνωστής υπο τον όρο Quality of Experience (QoE). Η παρούσα πτυχιακή αντιπροσωπεύει την προσπάθεια συγκερασμού των τριών ακόλουθων πυλώνων: της υποκείμενης υποδομής, του ελέγχου της ποιότητας υπηρεσίας με τη χρήση αλγορίθμων προσαρμογής και του επαναπροσδιορισμού του συστήματος με ανάλυση της ποιότητας και ανατροφοδότηση. Ανοίγει τη συζήτηση για τη χρήση προσαρμοζόμενης ροής μετάδοσης πάνω απο δίκτυα LTE και στοχεύει όχι μόνο να προσφέρει μια βαθιά βιβλιογραφική προσέγγιση των επιμέρους, αλλά και να περιγράψει πώς συνδέονται, πώς επικαλύπτονται, ή πώς αλληλεπιδρούν. Περιγράφει τα σημαντικότερα σύγχρονα μοντέλα μέτρησης QoE και πώς αυτά χρησιμεύουν στην αντικειμενική εκτίμηση της ποιότητας. Βασική συνεισφορά της εργασίας, είναι η ανάπτυξη μιάς πλήρης εκτελέσιμης οντότητας (module) για τον προσομοιωτή NS-3 συνδυάζοντας όλες τις έννοιες που αναφέρονται παραπάνω.Ο αναγνώστης μπορεί να βρεί ενα τυπικό παράδειγμα εκτέλεσης της εν λόγω οντότητας, με την συνοδεία μιας βήμα-βήμα εξήγησής του και και κάποιων διαγραμμάτων με αποτελέσματα. Το NS3 module αναπτύχθηκε με την ελπίδα να φανεί χρήσιμο σε κάθε ερευνητή τηλεπικοινωνιών που ασχολείται με θέματα παροχής ποιότητας εμπειρίας και αναζητά ένα εργαλείο προσομειώσεων.The ability to address an increasing need for mobility in work and entertainment has rendered LTE networks critically essential to our everyday environments. The promising 4th Generation (4G) of Long Term Evolution (LTE) provides ubiquitous broadband access to mobile devices matching land communications in speed and quality. However, the nature of mobility introduces a need for adaptivity in multimedia streaming, the largest part of mobile Internet traffic. As HTTP video streaming has become the de facto dominating solution to distribute media content, the implementation of an HTTP-based adaptive streaming protocol is inevitable. Dynamic Adaptive Streaming over HTTP (DASH) allows for smooth, uninterrupted video streaming by implementing bitrate adaptation algorithms on the client side, with complete utilization of the existing network infrastructure. In order to perfect the current quality served by the network, network researchers constantly develop new metrics to assess the end-user’s Quality of Experience. This thesis represents an attempt to join these three pillars of mobile video streaming: the underlying infrastructure, the over-the-top algorithmic quality control, and the follow-up feedback measurement. It opens a discussion about the use of adaptive streaming in LTE networks, and aims to offer not only a deep down bibliographic approach of each individual concept, but also describe where they overlap, how they connect and interact with each other. It depicts the most important contemporary QoE models and metrics, explains their formulas, and outlines their uses as key performance indicators in objective quality estimation. Furthermore, within this work, we provide a complete, expandable NS-3 model combining all the concepts discussed. An HTTP Server-Client model within the LTE network architecture, with implemented adaptive streaming functionality. The tool was developed in the hope of becoming useful to any telecommunications researcher, supporting their research and introducing them to the NS-3 simulator. In the end, we present a typical execution of our example with a step by step explanation, followed by the plotting of some of the results using a C++ script we developed

    Call admission control for interactive multimedia satellite networks.

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    Master of Science in Engineering (Electronic). University of KwaZulu-Natal, Durban 2015.Satellite communication has become an integral component of global access communication network due mainly to its ubiquitous coverage, large bandwidth and ability to support for large numbers of users over fixed and mobile devices. However, the multiplicity of multimedia applications with diverse requirements in terms of quality of service (QoS) poses new challenges in managing the limited and expensive resources. Furthermore, the time-varying nature of the propagation channel due to atmospheric and environmental effects also poses great challenges to effective utilization of resources and the satisfaction of users’ QoS requirements. Efficient radio resource management (RRM) techniques such as call admission control (CAC) and adaptive modulation and coding (AMC) are required in order to guarantee QoS satisfaction for user established connections and realize maximum and efficient utilization of network resources. In this work, we propose two CAC policies for interactive satellite multimedia networks. The two policies are based on efficient adaptation of transmission parameters to the dynamic link characteristics. In the first policy which we refer to as Gaussian Call Admission Control with Link Adaptation (GCAC-LA), we invoke the central limit theorem to statistically multiplex rate based dynamic capacity (RBDC) connections and obtain an aggregate bandwidth and required capacity for the multiplex. Adaptive Modulation and Coding (AMC) is employed for transmission over the time-varying wireless channel of the return link of an interactive satellite network. By associating users’ channel states to particular transmission parameters, the amount of resources required to satisfy user connection requirements in each state is determined. Thus the admission control policy considers in its decision, the channel states of all existing and new connections. The performance of the system is investigated by simulation and the results show that AMC significantly improves the utilization and call blocking performance by more than twice that of a system without link adaptation. In the second policy, a Game Theory based CAC policy with link adaptation (GTCAC-LA) is proposed. The admission of a new user connection under the GTCAC-LA policy is based on a non-cooperative game that is played between the network (existing user connections) and the new connection. A channel prediction scheme that predicts the rain attenuation on the link in successive intervals of time is also proposed. This determines the current resource allocation for every source at any point in time. The proposed game is played each time a new connection arrives and the strategies adopted by players are based on utility function, which is estimated based on the required capacity and the actual resources allocated. The performance of the CAC policy is investigated for different prediction intervals and the results show that multiple interval prediction scheme shows better performance than the single interval scheme. Performance of the proposed CAC policies indicates their suitability for QoS provisioning for traffic of multimedia connections in future 5G networks

    Convergence of packet communications over the evolved mobile networks; signal processing and protocol performance

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    In this thesis, the convergence of packet communications over the evolved mobile networks is studied. The Long Term Evolution (LTE) process is dominating the Third Generation Partnership Project (3GPP) in order to bring technologies to the markets in the spirit of continuous innovation. The global markets of mobile information services are growing towards the Mobile Information Society. The thesis begins with the principles and theories of the multiple-access transmission schemes, transmitter receiver techniques and signal processing algorithms. Next, packet communications and Internet protocols are referred from the IETF standards with the characteristics of mobile communications in the focus. The mobile network architecture and protocols bind together the evolved packet system of Internet communications to the radio access network technologies. Specifics of the traffic models are shortly visited for their statistical meaning in the radio performance analysis. Radio resource management algorithms and protocols, also procedures, are covered addressing their relevance for the system performance. Throughout these Chapters, the commonalities and differentiators of the WCDMA, WCDMA/HSPA and LTE are covered. The main outcome of the thesis is the performance analysis of the LTE technology beginning from the early discoveries to the analysis of various system features and finally converging to an extensive system analysis campaign. The system performance is analysed with the characteristics of voice over the Internet and best effort traffic of the Internet. These traffic classes represent the majority of the mobile traffic in the converged packet networks, and yet they are simple enough for a fair and generic analysis of technologies. The thesis consists of publications and inventions created by the author that proposed several improvements to the 3G technologies towards the LTE. In the system analysis, the LTE showed by the factor of at least 2.5 to 3 times higher system measures compared to the WCDMA/HSPA reference. The WCDMA/HSPA networks are currently available with over 400 million subscribers and showing increasing growth, in the meanwhile the first LTE roll-outs are scheduled to begin in 2010. Sophisticated 3G LTE mobile devices are expected to appear fluently for all consumer segments in the following years

    Cloud Radio Access Network architecture. Towards 5G mobile networks

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    Simulating LTE/LTE-Advanced Networks with SimuLTE

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    In this work we present SimuLTE, an OMNeT++-based simulator for LTE and LTE-Advanced networks. Following well-established OMNeT++ programming practices, SimuLTE exhibits a fully modular structure, which makes it easy to be extended, verified, and integrated. Moreover, it inherits all the benefits of such a widely used and versatile simulation framework as OMNeT++, i.e., experiment support and seamless integration with the OMNeT++ network modules, such as INET. This allows SimuLTE users to build up mixed scenarios where LTE is only a part of a wider network. This paper describes the architecture of SimuLTE, with particular emphasis on the modeling choices at the MAC layer, where resource scheduling is located. Furthermore, we describe some of the verification and validation efforts and present an example of the performance analysis that can be carried out with SimuLTE

    Telecommunications Networks

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    This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing

    Optimizing IETF multimedia signaling protocols and architectures in 3GPP networks : an evolutionary approach

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    Signaling in Next Generation IP-based networks heavily relies in the family of multimedia signaling protocols defined by IETF. Two of these signaling protocols are RTSP and SIP, which are text-based, client-server, request-response signaling protocols aimed at enabling multimedia sessions over IP networks. RTSP was conceived to set up streaming sessions from a Content / Streaming Server to a Streaming Client, while SIP was conceived to set up media (e.g.: voice, video, chat, file sharing, …) sessions among users. However, their scope has evolved and expanded over time to cover virtually any type of content and media session. As mobile networks progressively evolved towards an IP-only (All-IP) concept, particularly in 4G and 5G networks, 3GPP had to select IP-based signaling protocols for core mobile services, as opposed to traditional SS7-based protocols used in the circuit-switched domain in use in 2G and 3G networks. In that context, rather than reinventing the wheel, 3GPP decided to leverage Internet protocols and the work carried on by the IETF. Hence, it was not surprise that when 3GPP defined the so-called Packet-switched Streaming Service (PSS) for real-time continuous media delivery, it selected RTSP as its signaling protocol and, more importantly, SIP was eventually selected as the core signaling protocol for all multimedia core services in the mobile (All-)IP domain. This 3GPP decision to use off-the-shelf IETF-standardized signaling protocols has been a key cornerstone for the future of All-IP fixed / mobile networks convergence and Next Generation Networks (NGN) in general. In this context, the main goal of our work has been analyzing how such general purpose IP multimedia signaling protocols are deployed and behave over 3GPP mobile networks. Effectively, usage of IP protocols is key to enable cross-vendor interoperability. On the other hand, due to the specific nature of the mobile domain, there are scenarios where it might be possible to leverage some additional “context” to enhance the performance of such protocols in the particular case of mobile networks. With this idea in mind, the bulk of this thesis work has consisted on analyzing and optimizing the performance of SIP and RTSP multimedia signaling protocols and defining optimized deployment architectures, with particular focus on the 3GPP PSS and the 3GPP Mission Critical Push-to-Talk (MCPTT) service. This work was preceded by a detailed analysis work of the performance of underlying IP, UDP and TCP protocol performance over 3GPP networks, which provided the best baseline for the future work around IP multimedia signaling protocols. Our contributions include the proposal of new optimizations to enhance multimedia streaming session setup procedures, detailed analysis and optimizations of a SIP-based Presence service and, finally, the definition of new use cases and optimized deployment architectures for the 3GPP MCPTT service. All this work has been published in the form of one book, three papers published in JCR cited International Journals, 5 articles published in International Conferences, one paper published in a National Conference and one awarded patent. This thesis work provides a detailed description of all contributions plus a comprehensive overview of their context, the guiding principles beneath all contributions, their applicability to different network deployment technologies (from 2.5G to 5G), a detailed overview of the related OMA and 3GPP architectures, services and design principles. Last but not least, the potential evolution of this research work into the 5G domain is also outlined as well.Els mecanismes de Senyalització en xarxes de nova generació es fonamenten en protocols de senyalització definits per IETF. En particular, SIP i RTSP són dos protocols extensibles basats en missatges de text i paradigma petició-resposta. RTSP va ser concebut per a establir sessions de streaming de continguts, mentre SIP va ser creat inicialment per a facilitar l’establiment de sessions multimèdia (veu, vídeo, xat, compartició) entre usuaris. Tot i així, el seu àmbit d’aplicació s’ha anat expandint i evolucionant fins a cobrir virtualment qualsevol tipus de contingut i sessió multimèdia. A mesura que les xarxes mòbils han anat evolucionant cap a un paradigma “All-IP”, particularment en xarxes 4G i 5G, 3GPP va seleccionar els protocols i arquitectures destinats a gestionar la senyalització dels serveis mòbils presents i futurs. En un moment determinat 3GPP decideix que, a diferència dels sistemes 2G i 3G que fan servir protocols basats en SS7, els sistemes de nova generació farien servir protocols estandarditzats per IETF. Quan 3GPP va començar a estandarditzar el servei de Streaming sobre xarxes mòbils PSS (Packet-switched Streaming Service) va escollir el protocol RTSP com a mecanisme de senyalització. Encara més significatiu, el protocol SIP va ser escollit com a mecanisme de senyalització per a IMS (IP Multimedia Subsystem), l’arquitectura de nova generació que substituirà la xarxa telefònica tradicional i permetrà el desplegament de nous serveis multimèdia. La decisió per part de 3GPP de seleccionar protocols estàndards definits per IETF ha representat una fita cabdal per a la convergència del sistemes All-IP fixes i mòbils, i per al desenvolupament de xarxes NGN (Next Generation Networks) en general. En aquest context, el nostre objectiu inicial ha estat analitzar com aquests protocols de senyalització multimèdia, dissenyats per a xarxes IP genèriques, es comporten sobre xarxes mòbils 3GPP. Efectivament, l’ús de protocols IP és fonamental de cara a facilitar la interoperabilitat de solucions diferents. Per altra banda, hi ha escenaris a on és possible aprofitar informació de “context” addicional per a millorar el comportament d’aquests protocols en al cas particular de xarxes mòbils. El cos principal del treball de la tesi ha consistit en l’anàlisi i optimització del rendiment dels protocols de senyalització multimèdia SIP i RTSP, i la definició d’arquitectures de desplegament, amb èmfasi en els serveis 3GPP PSS i 3GPP Mission Critical Push-to-Talk (MCPTT). Aquest treball ha estat precedit per una feina d’anàlisi detallada del comportament dels protocols IP, TCP i UDP sobre xarxes 3GPP, que va proporcionar els fonaments adequats per a la posterior tasca d’anàlisi de protocols de senyalització sobre xarxes mòbils. Les contribucions inclouen la proposta de noves optimitzacions per a millorar els procediments d’establiment de sessions de streaming multimèdia, l’anàlisi detallat i optimització del servei de Presència basat en SIP i la definició de nous casos d’ús i exemples de desplegament d’arquitectures optimitzades per al servei 3GPP MCPTT. Aquestes contribucions ha quedat reflectides en un llibre, tres articles publicats en Revistes Internacionals amb índex JCR, 5 articles publicats en Conferències Internacionals, un article publicat en Congrés Nacional i l’adjudicació d’una patent. La tesi proporciona una descripció detallada de totes les contribucions, així com un exhaustiu repàs del seu context, dels principis fonamentals subjacents a totes les contribucions, la seva aplicabilitat a diferents tipus de desplegaments de xarxa (des de 2.5G a 5G), així una presentació detallada de les arquitectures associades definides per organismes com OMA o 3GPP. Finalment també es presenta l’evolució potencial de la tasca de recerca cap a sistemes 5G.Postprint (published version

    Network reputation-based quality optimization of video delivery in heterogeneous wireless environments

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    The mass-market adoption of high-end mobile devices and increasing amount of video traffic has led the mobile operators to adopt various solutions to help them cope with the explosion of mobile broadband data traffic, while ensuring high Quality of Service (QoS) levels to their services. Deploying small-cell base stations within the existing macro-cellular networks and offloading traffic from the large macro-cells to the small cells is seen as a promising solution to increase capacity and improve network performance at low cost. Parallel use of diverse technologies is also employed. The result is a heterogeneous network environment (HetNets), part of the next generation network deployments. In this context, this thesis makes a step forward towards the “Always Best Experience” paradigm, which considers mobile users seamlessly roaming in the HetNets environment. Supporting ubiquitous connectivity and enabling very good quality of rich mobile services anywhere and anytime is highly challenging, mostly due to the heterogeneity of the selection criteria, such as: application requirements (e.g., voice, video, data, etc.); different device types and with various capabilities (e.g., smartphones, netbooks, laptops, etc.); multiple overlapping networks using diverse technologies (e.g., Wireless Local Area Networks (IEEE 802.11), Cellular Networks Long Term Evolution (LTE), etc.) and different user preferences. In fact, the mobile users are facing a complex decision when they need to dynamically select the best value network to connect to in order to get the “Always Best Experience”. This thesis presents three major contributions to solve the problem described above: 1) The Location-based Network Prediction mechanism in heterogeneous wireless networks (LNP) provides a shortlist of best available networks to the mobile user based on his location, history record and routing plan; 2) Reputation-oriented Access Network Selection mechanism (RANS) selects the best reputation network from the available networks for the mobile user based on the best trade-off between QoS, energy consumptions and monetary cost. The network reputation is defined based on previous user-network interaction, and consequent user experience with the network. 3) Network Reputation-based Quality Optimization of Video Delivery in heterogeneous networks (NRQOVD) makes use of a reputation mechanism to enhance the video content quality via multipath delivery or delivery adaptation

    Analysis and performance evaluation of the next generation wireless networks

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    International audienceExponential growth in demand for high bandwidth applications such as multimedia in cellular networks has triggered the need for development of new technologies capable of providing the required high bandwidth, reliable links in wireless environments. However, the available spectrum is a limited natural resource and the current technologies have been shown to have low spectrumefficiency. To improve the spectrum efficiency, heterogeneous networks are considered as a viable solution. They are composed of a mix of macro, pico, femto and relay base-stations that improve the spectrum efficiency and throughput performance of the system. The aim of this chapter is to provide an overview of these emerging technologies. This chapter describes the main characteristics and performance requirements that the next generation networks must fulfill. Particularly, the focus is on Long Term Evolution (LTE)/LTE-Advanced technologies where some possible improvements and challenges are explained. Subsequently, the analytical methods and simulations techniques to evaluate the performance of the next generation heterogeneous networks are discussed. Finally, the simulation results for some example scenarios are provided and discussed
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