Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 2009

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores. Universidade do Porto. Faculdade de Engenharia. 2011

Estágio realizado na Sun Microsystems Ireland Inc / Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2009

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2010

Internet protocol TV (IPTV) is predicted to be the key technology winner in the future. Efforts to accelerate the deployment of IPTV centralized model which is combined of VHO, encoders, controller, access network and Home network. Regardless of whether the network is delivering live TV, VOD, or Time-shift TV, all content and network traffic resulting from subscriber requests must traverse the entire network from the super-headend all the way to each subscriber's Set-Top Box (STB).IPTV services require very stringent QoS guarantees When IPTV traffic shares the network resources with other traffic like data and voice, how to ensure their QoS and efficiently utilize the network resources is a key and challenging issue. For QoS measured in the network-centric terms of delay jitter, packet losses and bounds on delay. The main focus of this thesis is on the optimized bandwidth allocation and smooth datatransmission. The proposed traffic model for smooth delivering video service IPTV network with its QoS performance evaluation. According to Maglaris et al [5] First, analyze the coding bit rate of a single video source. Various statistical quantities are derived from bit rate data collected with a conditional replenishment inter frame coding scheme. Two correlated Markov process models (one in discrete time and one incontinuous time) are shown to fit the experimental data and are used to model the input rates of several independent sources into a statistical multiplexer. Preventive control mechanism which is to be include CAC, traffic policing used for traffic control.QoS has been evaluated of common bandwidth scheduler( FIFO) by use fluid models with Markovian queuing method and analysis the result by using simulator andanalytically, Which is measured the performance of the packet loss, overflow and mean waiting time among the network users.

Internet protocol TV (IPTV) is predicted to be the key technology winner in the future. Efforts to accelerate the deployment of IPTV centralized model which is combined of VHO, encoders, controller, access network and Home network. Regardless of whether the network is delivering live TV, VOD, or Time-shift TV, all content and network traffic resulting from subscriber requests must traverse the entire network from the super-headend all the way to each subscriber's Set-Top Box (STB). IPTV services require very stringent QoS guarantees When IPTV traffic shares the network resources with other traffic like data and voice, how to ensure their QoS and efficiently utilize the network resources is a key and challenging issue. For QoS measured in the network-centric terms of delay jitter, packet losses and bounds on delay. The main focus of this thesis is on the optimized bandwidth allocation and smooth data transmission. The proposed traffic model for smooth delivering video service IPTV network with its QoS performance evaluation. According to Maglaris et al [5] first, analyze the coding bit rate of a single video source. Various statistical quantities are derived from bit rate data collected with a conditional replenishment inter frame coding scheme. Two correlated Markov process models (one in discrete time and one in continuous time) are shown to fit the experimental data and are used to model the input rates of several independent sources into a statistical multiplexer. Preventive control mechanism which is to be including CAC, traffic policing used for traffic control. QoS has been evaluated of common bandwidth scheduler( FIFO) by use fluid models with Markovian queuing method and analysis the result by using simulator and analytically, Which is measured the performance of the packet loss, overflow and mean waiting time among the network users.

Το αντικείμενο της παρούσας διπλωματικής εργασίας είναι η μελέτη της ψηφιακής τηλεόρασης μέσω πρωτόκολλου Internet, γνωστής και ως IPTV (Internet Protocol TeleVision) με ιδιαίτερη εστίαση στον αποκωδικοποιητή που χρησιμοποιείται για την επίτευξη της τηλεοπτικής μετάδοσης. Αυτός ο αποκωδικοποιητής ονομάζεται Set-Top Box. Στην ουσία το IPTV είναι η μετάδοση τηλεοπτικού σήματος μέσω ευρυζωνικής σύνδεσης που χρησιμοποιεί το πρωτόκολλο IP μέσω ενός ιδιωτικού κλειστού δικτύου και όχι του δημοσίου Internet. Το IPTV θεωρείται το παρόν και το μέλλον όσον αφορά τα είδη τηλεόρασης καθώς ο χρήστης έχει την δυνατότητα για πρόσβαση σε τηλεοπτικά κανάλια με ψηφιακή εικόνα ενώ η δυνατότητα που παρέχουν οι on-demand υπηρεσίες για παρακολούθηση τηλεοπτικού περιεχομένου παντός τύπου την ώρα που επιθυμεί ο χρήστης καθιστά το «πακέτο» πολύ πιο ελκυστικό. Συγκεκριμένα, σε αυτή την διπλωματική εργασία, παρουσιάζεται αρχικά ο ορισμός της δικτυακής τηλεόρασης και γενικά όλων αυτών που συνέβαλλαν στην δημιουργία του IPTV. Κατόπιν γίνεται μια συνοπτική ιστορική αναδρομή στα γεγονότα που οδήγησαν στην μορφή του IPTV όπως την ξέρουμε σήμερα. Έπειτα συγκρίνεται το IPTV με το γνωστό μας Internet TV. Στην συνέχεια γίνεται μια γενική περιγραφή ενός δικτύου IPTV ενώ έπειτα εμβαθύνουμε περισσότερο καθώς περιγράφονται και τεχνικές λεπτομέρειες για ένα τέτοιο δίκτυο. Ακολούθως περιγράφονται οι κωδικοποιήσεις που πραγματοποιούνται αλλά και οι διάφορές τους. Επιπλέον γίνεται ιδιαίτερη αναφορά και ανάλυση στα διάφορα είδη των αποκωδικοποιητών (Set-Top Box) που χρησιμοποιούνται και επισημαίνονται οι διαφορές που έχουν στη δομή και στα χαρακτηριστικά τους. Τέλος γίνεται μια αναφορά στους παρόχους πακέτων IPTV στην Ελλάδα ενώ γίνεται και μια σύγκριση αυτών των πακέτων μεταξύ τους. / The theme of this particular thesis is the study of the digital television via Internet protocol, also known as IPTV (Internet Protocol TeleVision) with special focusing on the decoder which is used in order to achieve television broadcasting. This decoder is called Set-Top Box. Essentially, IPTV is the transmission of television signals over broadband which is using IP protocol through a closed private network and not the public Internet. IPTV is considered to be the present and the future regarding the types of television because the user has the ability to access TV channels with digital view, while the ability provided by on-demand services about watching every type of television content at every time the user wants makes the whole “package” much more attractive. Particularly, in this thesis, is firstly presented the definition of networking TV and generally of all these things which have contributed to the creation of IPTV. Following is a brief historical background to the events that led to the form of IPTV as we know it today. Afterwards, the IPTV is compared to the Internet TV, which is familiar to us. After that, a general description of an IPTV network is taking place and then we go further as technical details of such a network are described. Moreover, the encodings performed and their differences are mentioned. Additionally, there is much reporting and analysis in various types of decoders (Set-Top Box) used and marked the differences they have on their structure and their profile. Finally, there is a reference to IPTV packet providers in Greece and is happening a comparison among these packets.

Cette thèse concerne l'investigation détaillée du problème du temps de zapping dans les réseaux d'opérateurs offrant un service IPTY basé sur la technologie multicast. Cette investigation a conduit à plusieurs contributions qui permettent de substantiellement améliorer le temps de zapping dans ce type de réseau. Notre première contribution concerne la partie purement réseau. Nous avons proposé d'optimiser le processus de changement de chaîne et ceci pour chaque version du protocole IGMP. Cette optimisation réduit la latence due au réseau sans pour autant augmenter la consommation de bande passante d'une manière significative. Nous avons modélisé le service IPTV Multicast pour estimer les pics de consommation de la bande passante pour permettre à l'opérateur de dimensionner son réseau. La deuxième contribution concerne la partie traitement du flux IPTV par le récepteur. Dans cette partie, nous avons proposé d'associer au flux principal un flux secondaire, version retardée du principal. La construction du flux secondaire se fait en donnant une priorité élevée aux paquets transportant des éléments d'une I-Frame par rapport à d'autres types d'éléments (P­ Frame, B-Frame, Voix et Data). Cette nouvelle règle de construction permet de réduire le délai d'attente de la première I­Frame nécessaire pour commencer la phase de décodage tout en réduisant le temps de remplissage du buffer. Dans un environnement réel, nous avons évalué cette contribution et constaté une réduction remarquable du temps de zapping. / This thesis involves a detailed investigation of the problem of IPTV zapping time in networks of operators providing IPTV service based on multicast technology. This investigation led to some contributions that can substantially improve the channel change time in this type of network.Our first contribution concerns the pure network. We proposed an optimization of the channels changing process for each version of the IGMP protocol. This optimization reduces network latency without significantly increasing the bandwidth consumption. We proposed also a model of multicast IPTV service that we used to estimate the maximum bandwidth demand. This model enables the operator to size the bandwidth availability in its network.The second contribution relates to the processing part of stream IPTV on the receiver. In this section, we proposed to combine the main flow to a secondary flow, delayed version of the main stream. The construction of the secondary stream is clone by giving high priority to packets carrying elements of an I-frame compared to other types of elements (P-Frame, B­-Frame, Voice and Data). This rule of construction can reduce the First I-Frame Delay required to start the decoding phase and at the same time reduce the Buffering Delay. In a real environment, we evaluated this contribution and measured a remarkable decline of the zapping time with our proposal.

Service providers strive to guarantee a certain level of quality of their services, to stay relevant and to keep their customers satisfied and to avoid customer churn. IPTV is such a service. To be able to guarantee quality of service and uptime a good problem management system is vital. Problem management system, are a system of handling occurrences and solutions of all problems and errors. Its primary goal is to detect, prevent and solve errors and incidents, but also prevent reoccurring errors and minimizing the time line of existing problems by finding its root cause. On first contact of a problem there is human operators classifying the problem. Problems with problem management is that it is reactive and problems keep happening. To be able to become pro-active, problems need to be predicted before they occur. This thesis evaluates past problems to enable pro-active actions, by statistics and actionable data mining, using performance data from IPTV service and set top boxes, not utilized today by the company this thesis is carried out for. The result shows that pro-active actions are enabled by adding supervision of the performance data and a packet error ratio. The result also shows that some large problems gets classified too late. By utilizing machine learning and predictive modelling: Logistic regression and Artificial neural network, future disturbance incidents can be predicted. Using disturbance data gave a model accuracy of 80% and 80% respectively with a model Matthew correlation coefficient of 0.50 and 0.56 respectively. Given information of affected active service consumers, if provided, customer impact could easier be assessed. The larger part of this project went to the business understanding, data understanding, data preparation and analysis. By utilizing the unutilized performance data, the problem management system can become more proactive, with the addition of supervision of the IPTV performance data and predictive modelling. / Tjänsteleverantörer strävar att kunna garantera en viss grad av kvalité på de tjänster de erbjuder, för att fortsätta vara relevant, hålla sina kunder nöjda och undvika bortfall av kunder. IPTV är en sådan tjänst. För att kunna garantera en hög tjänstekvalité och hög drifttid, är ett bra problemhanteringssystem viktigt. Problemhanteringssystem är ett system som hanterar förekomsten av och lösningar till alla problem och fel. Dess primära mål är att upptäcka, motverka och lösa incidenter och fel. Även att motverka fortsatt upprepande fel samt att minimera tidslinjen för aktiva fel genom att hitta dess grundorsaken. Vid första kontakt av ett problem så är det mänskliga operatörer som klassificerar problemet. Ett problem med problemhanteringssystem är att de är reaktiva och problem fortsätter att uppkomma. För att kunna bli proaktiv, måste problem kunna predikteras innan de uppkommer. Denna uppsats utvärderar och analyserar gamla problem och incidenter för att möjliggöra proaktivitet, genom statistik och handlingsbar data mining, genom användandet av oanvända prestandadata från IPTV tjänst och digitalbox. Resultat visar att proaktivt agerande möjliggörs genom att lägga till bevakning av prestandadata och en paketfels kvot. Resultat visar även att stora problem blir klassificerad för sent. Genom användandet av maskininlärning och prediktiva modeller: logistisk regression och artificiellt neuralt nätverk, kan kommande incidenter predikteras. Användning av störningsdata gav en modellsäkerhet på 80% och 80% med en Matthew korrelations koefficient på 0.50 och 0.56 respektive. Information om antal aktiva påverkade kunder, om implementerat, hjälper till att bedöma kundpåverkan. Den större delen av detta projekt gick åt till företag förståelse, data förståelse, data förberedning och analys. Men genom användandet av prestandadata, kan problemhanteringssystemet bli proaktiv med tillägget av bevakning av IPTV tjänst och digitalbox data och prediktiv modellering.