<p>TV and radio services have always been distributed over analogue broadcasting networks and been received on a TV -set or a radio receiver. Today this situation is changing due to digitalization and convergence between broadcasting, telecommunications and data communications. Other terminals, such as a PC, can also receive TV and radio services. Digital TV and radio can offer additional services such as e-commerce, electronic program guides and content synchronized to the TV and radio shows. If these services are to be received by several receiving terminals with different properties, the services must be adapted to the terminals. This can be done by scaling the services, meaning that the appearances and functionality of the services vary depending on the terminals’ properties. In this thesis scalable services are examined from a terminal point of view. Present and future receivers, platforms and possible methods to achieve scalability are presented, and their effects on scalable services are discussed.</p> / <p>TV- och radiosändningar har fram till nyligen endast distribuerats över analoga TV- och radionät och tagits emot av traditionella TV- och radioapparater, men detta håller på att ändras i och med att sändningarna digitaliseras och konvergens sker mellan broadcasting, telekom och datakom. Nu kan även andra terminaler fungera som mottagare, t.ex. en PC med ett digital-TVkort eller ett digital-radiokort. Digital TV och radio erbjuder tilläggstjänster som t.ex. ehandel, tjänster kopplade till radio- eller TV-program och elektroniska programguider. Om samma tjänst ska kunna tas emot på flera olika mottagarterminaler med olika egenskaper, måste tjänsten anpassas efter terminalerna. Detta kan göras genom att skala tjänsten, dvs. utseendet och funktionerna varierar beroende på bl.a. terminalens kapacitet. I detta arbete har terminalaspekterna på skalbara tjänster undersökts. Aktuella och framtida terminaler, plattformar och eventuella skalbarhetslösningar presenteras, och deras påverkan på skalbara tjänster diskuteras.</p>

<p>Digital television broadcasters use conditional access (CA) systems to protect some of their services from being viewed by people not subscribing for these services. A manufacturer of digital television receivers develops applications to handle the CA systems that the receiver shall support. A problem for the application developer is that a CA application developed for one specific CA system is usually not reusable for other CA systems because of the differences between CA systems. The CA systems are different in both their application programming interfaces (API) as well as the types of functionality that they support. </p><p>This master thesis presents a study of three APIs from different CA systems. The possibilities of defining a new CA API that supports all the functionality that is provided by existing CA APIs while still being as similar as possible to these existing APIs are investigated. The conclusion from the study is that it is not possible to define this new CA API because the studied CA systems are so different and only small parts of the provided functionality are shared between them.</p>

Im Rahmen der vorliegenden Diplomarbeit wurden etablierte Systemsoftware-Updatefunktionen von DVB-Empfangsgeräten untersucht. Auf der Grundlage einer gezielten Analyse der Nutzersicht auf diese Systeme wurden dabei wiederkehrende Problematiken in der Durchführung aufgedeckt und mangelhafte Benutzer-Transparenz sowie deren Konsequenzen beleuchtet. Die Studie erfolgt in Form einer Online-Umfrage unter Nutzern themenbezogener Fach- bzw. Diskussionsforen. Mittels einer kritischen Bewertung der existierenden Systemsoftware-Updatemodelle unter gleichzeitiger Berücksichtigung der Hersteller- und Nutzerinteressen erfolgte eine Favorisierung, bei welcher die Updatemethoden „Over the Air“ und „Internet“ die günstigsten Voraussetzungen zeigten. An diesen wurden Ideenansätze mit dem Ziel einer weitergehenden Modelloptimierung diskutiert und konkretisiert. Im Ergebnis erwies sich die optimierte Variante der Updatemethode „Internet“ im Sinne der untersuchten Aspekte als besonders zweckmäßig. Als Praxisversuch wurde eine Systemsoftware-Updatefunktion unter Einbeziehung der Verbesserungen in einer VDR-Umgebung erfolgreich implementiert und getestet. Der großen Funktionsvielfalt dieses Multimedia-Entertainment-Systems und der Überschaubarmachung dieser für den Nutzer wurde dabei Rechnung getragen.

All digital-TV receivers that are existent on the market today include some sort of a multiplexer which filters the data, the sound and the picture from the digital stream. These de-multiplexers are rather complex and general. The purpose of this Master Thesis is to develop a de-multiplexer which would solely filter one specific type of information out of the data stream, in our case the name of the network. The main task of this project contains a close study of MPEG2 and the transport streams in order to find a solution and create a static de-multiplexer. Another part of this project is to choose an adequate method for the control and data communication. We will study the bus protocols I2C and SPI. Finally we will construct the entire circuit after having chosen the Development Environment, DE and considered all the different circuit designs suitable for our task as well as the working at a low production cost, which is of course an important factor and challenge. The first part of construction will be made in Very High Speed Integrated Circuit Hardware Description Language, VHDL, code and once the program is tested and working we will implement it and create the circuit. We will run a test of the final circuit test by filtering a near satellite signal and the get the name of the aimed network.

Satellite networks provide an alternative to terrestrial networks where cost and lack of infrastructure are driving parameters. For a satellite network to be cost effective one needs to be able to increase the efficiency of the network: this is accomplished by focusing on the parameters that affect the performance of the system and improving on them where possible. The factors affecting the network performance include the capacity, the propagation delay, the protocol used, and the channel error rate, among others. There are various ways to implement a satellite network depending on the satellite orbit, the architecture used, the access technique used, the radio interfaces used, etc. This thesis work describes the chosen satellite standard, Digital Video Broadcasting – Return Channel via Satellite (DVB-RCS) and the associated Medium Access Control (MAC) protocols. Two protocols were designed and investigated under ideal channel conditions, these being the Combined Free/Demand Assigned Multiple Access with Piggy Backing – Packet Dropping (CF/DAMA-PB-PD) protocol; and the Combined Free/Demand Assigned Multiple Access with Piggy Backing – Prioritised Earliest Deadline First (CF/DAMA-PB-PEDF) protocol, both derived from the Combined Free/Demand Assigned Multiple Access with Piggy Backing (CF/DAMA-PB) protocol. The multimedia traffic models for voice, video and web classes are described, validated through simulations and presented; these provide the heterogeneous vi traffic required for evaluating the performance of the satellite system implemented and the designed protocols. Under the multimedia traffic, CF/DAMA-PB-PD was shown to excel in average packet delay reduction while reducing the overall system throughput. The CF/DAMA-PB-PEDF does not contribute to an improvement over the CF/DAMA-PB-PD protocol. The effects of a non-ideal channel on the CF/DAMA-PB-PD protocol was investigated and presented along with the design of three MAC protocols that take the channel characteristics into account to improve on the system performance. The cross-layer interactions, more specifically the interaction between the physical and data–link layers, were used, investigated and presented. The channel state information in terms of signal-to-noise ratio (SNR) was used to improve the system performance. The five protocols evaluated under non-ideal channel conditions were the CF/DAMA-PB, CF/DAMA-PB-PD, CF/DAMA-PB-BSNRF, CF/DAMA-PB-DD and the CF/DAMA-PB-BSNRF+DD. The best overall performance, both in average packet delay while maintaining good QoS levels and throughput was shown to be that of the CF/DAMA-PB-DD protocol. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

Ένα από τα βασικά μειονεκτήματα που παρουσιάζει ο σχεδιασμός και η υλοποίηση LDPC αποκωδικοποιητών είναι η μεγάλη πολυπλοκότητα που παρουσιάζεται σε επίπεδο υλικού εξαιτίας της εσωτερικής διασύνδεσης των μονάδων επεξεργασίας δεδομένων.H αρχιτεκτονική που επιτυγχάνει το μέγιστο επίπεδο παραλληλότητας και κατά συνέπεια είναι πολύ αποδοτική όσον αφορά την ταχύτητα αποκωδικοποίησης, δεν χρησιμοποιείται συχνά εξαιτίας της πολυπλοκότητας του υλικού λόγω των πολλαπλών κυκλωμάτων διασύνδεσης που απαιτεί. Στην παρούσα διπλωματική εργασία προτείνεται μια νέα αρχιτεκτονική για το δίκτυο διασύνδεσης ενώ παράλληλα έχει υλοποιηθεί και ένας αλγόριθμος για την αποδοτική τοποθέτηση των επεξεργαστικών μονάδων σε αυτό το δίκτυο. Επίσης έχει μελετηθεί και η επίδραση μειωμένης μετάδοσης πληροφορίας σε κάθε επανάληψη του αλγορίθμου αποκωδικοποίησης.Το περιβάλλον που χρησιμοποιήθηκε για την εξομοίωση και την παραγωγή των αποτελεσμάτων είναι η πλατφόρμα της Matlab. Η προτεινόμενη αρχιτεκτονική υλοποιήθηκε και εξομοιώθηκε σε κώδικες LDPC που αποτελούν μέρος του προτύπου DVB - S2 (Digital Video Broadcasting).Το συγκεκριμένο πρότυπο, εκτός των άλλων, καθορίζει και τις προδιαγραφές των κωδίκων LDPC που χρησιμοποιούνται κατά την κωδικοποίηση και αποκωδικοποίηση δεδομένων σε συστήματα ψηφιακής δορυφορικής μετάδοσης. Τα αποτελέσματα των εξομοιώσεων σχετίζονται με την πολυπλοκότητα της προτεινόμενης αρχιτεκτονικής σε υλικό αλλά και της απόδοσης (ταχύτητα αποκωδικοποίησης) και συγκρίνονται με την βασική πλήρως παράλληλη αρχιτεκτονική. / One of the main disadvantages of the design and implementation of LDPC decoders is the great complexity presented at the hardware level because of the internal interconnection of processing units. The fully parallel architecture that achieves the maximum level of parallelism and hence is very efficient in terms of speed decoding is not used often because of the hardware complexity due to the multiple interface circuits required. This MSc thesis proposes a new architecture for the network interface and also introduces an algorithm for the efficient placement of the processing units in this network. In addition to that, a modified version of the decoding algorithm has been implemented. The relative advantage of this algorithm is that in each iteration only a percentage of the processing units exchange information with each other. That approach further reduces the hardware complexity and power usage. The environment used to simulate and produce the results is Matlab. The proposed architecture is implemented and simulated in LDPC codes that are part of the standard DVB - S2 (Digital Video Broadcasting). This standard, among other things, determines the specifications of the LDPC codes used in the channel encoding and decoding process in digital satellite transmission systems. The results of the simulations related to the complexity of the proposed architecture in hardware and performance (decoding speed) are compared with the fully parallel architecture.

H παρούσα πτυχιακή εργασία επικεντρώνεται αρχικά, στη μελέτη των προτύπων της επίγειας και φορητής ψηφιακής τηλεοράσης (DVB-T και DVB-H). Το DVB-T αποτελεί τo πρότυπο της επίγειας µετάδοσης που έχει αναπτυχθεί µε ιδιαίτερα πολύπλοκο τρόπο από ότι τα προηγούµενα πρότυπα για δορυφορική και καλωδιακή µετάδοση. Με το DVB-T επιτυγχάνονται καλύτερες επιδόσεις απ’ ότι µε την αναλογική μετάδοση και προσφέρει πολλά πλεονεκτήµατα στην επίγεια µετάδοση αλλά και λήψη του σήµατος. Επειδή αποδείχθηκε σχετικά νωρίς ότι το DVB-T έχει μειονεκτήματα σε ότι αφορά το broadcasting τηλεοπτικού σήματος σε κινητά τηλέφωνα, γεννήθηκε η ιδέα για ένα σύστημα αποκλειστικά για φορητές συσκευές βασισμένο στο DVB-T. Καλείται DVB-H (DVB-Handheld). Δεδομένου ότι τα συστήματα ψηφιακής μετάδοσης DVB-T και DVB-H χρησιμοποιούν για τη διάδοσή τους το επίγειο και δορυφορικό κανάλι, γίνεται εκτενής ανάλυση των παραμέτρων που επηρεάζουν την επίγεια και δορυφορική μετάδοση, κυρίως από την οπτική των απωλειών. Στη συνέχεια, γίνεται ανάλυση όλων των σταδίων που λαμβάνουν χώρα κατά την εκπομπή και λήψη ενός OFDM σήματος μέσω ενός φυσικού καναλιού, διαμόρφωση η οποία χρησιμοποιείται κατά κόρον στα πρότυπα DVB-T και DVB-H. Έπειτα, προσομοιώνουμε μέσω του MATLAB όλη τη διαδικασία της OFDM μετάδοσης και λήψης, εξάγοντας τις γραφικές παραστάσεις με τη μορφή του OFDM σήματος σε κάθε στάδιο. Τέλος, θα μελετήσουμε την επίδραση του ασύρματου καναλιού (δορυφορικού και επίγειου) στην εξασθένηση του OFDM σήματος, στο σταθμό λήψης και θα εξάγουμε τις γραφικές παραστάσεις, επιβεβαιώνοντας την εξασθένηση αυτή. / This project focuses initially on the study of patterns of terrestrial and mobile digital television (DVB-T and DVB-H). The DVB-T standard is the terrestrial broadcasting standard that has been developed in a very complex way than previous standards for satellite and cable broadcasting. By implementing DVB-T we can achieve much better performance than analog transmission as it offers many advantages for terrestrial transmission and reception. Since it has been proved early on that the DVB-T has disadvantages in terms of the broadcasting of television signals to mobile phones, there has been created an idea for a system that exclusively focuses on mobile devices, based on DVB-T. It is called DVB-H (DVB-Handheld). Since the digital broadcasting systems of DVB-T and DVB-H use the terrestrial and satellite channel to transmit information, an extensive analysis of parameters affecting the terrestrial and satellite transmission takes place, mainly from the perspective of losses. Then, there takes place an analysis of all stages that occur when transmitting and receiving an OFDM signal through a natural channel, modulation which is widely used in DVB-T and DVB-H. Then, we run a MATLAB simulation for the whole process of OFDM transmission and reception, exporting graphs of the form of the OFDM signal at each stage. Finally, we will study the effect of wireless channel (satellite and terrestrial) as far as the weakening of the OFDM signal is concerned at the receiving station and we will export the graphs, confirming the aforementioned attenuation. .

Passive coherent location (PCL) radars employ illuminators of opportunity to detect and track targets. This silent operating mode provides many advantages such as low cost and interception immunity. Many radiation sources have been exploited as illumination sources such as broadcasting and telecommunication transmitters. The classical architecture of the bistatic PCL radars involves two receiving channels: a reference channel and a surveillance channel. The reference channel captures the direct-path signal from the transmitter, and the surveillancesignal collects the possible target echoes. The two major challenges for the PCL radars are the reference signal noise and the surveillance signal static clutter. A noisy reference signal degrades the detection probability by increasing the noise-floor level of the detection filter output. And the static clutter presence in the surveillance signal reduces the detector dynamic range and buries low magnitude echoes.In this thesis, we consider a PCL radar based on the digital video broadcasting-terrestrial (DVB-T) signals, and we propose a set of improved methods to deal with the reference signal noise and the static clutter in the surveillance signal. The DVB-T signals constitute an excellentcandidate as an illumination source for PCL radars; they are characterized by a wide bandwidth and a high radiated power. In addition, they provide the possibility of reconstructing the reference signal to enhance its quality, and they allow a straightforward static clutter suppressionin the frequency domain. This thesis proposes an optimum method for the reference signal reconstruction and an improved method for the static clutter suppression.The optimum reference signal reconstruction minimizes the mean square error between the reconstructed signal and the exact one. And the improved static clutter suppression method exploits the possibility of estimating the propagation channel. These two methods extend thefeasibility of a single receiver PCL radar, where the reference signal is extracted from the direct-path signal present in the surveillance signal. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Digital television broadcasters use conditional access (CA) systems to protect some of their services from being viewed by people not subscribing for these services. A manufacturer of digital television receivers develops applications to handle the CA systems that the receiver shall support. A problem for the application developer is that a CA application developed for one specific CA system is usually not reusable for other CA systems because of the differences between CA systems. The CA systems are different in both their application programming interfaces (API) as well as the types of functionality that they support. This master thesis presents a study of three APIs from different CA systems. The possibilities of defining a new CA API that supports all the functionality that is provided by existing CA APIs while still being as similar as possible to these existing APIs are investigated. The conclusion from the study is that it is not possible to define this new CA API because the studied CA systems are so different and only small parts of the provided functionality are shared between them.

TV and radio services have always been distributed over analogue broadcasting networks and been received on a TV -set or a radio receiver. Today this situation is changing due to digitalization and convergence between broadcasting, telecommunications and data communications. Other terminals, such as a PC, can also receive TV and radio services. Digital TV and radio can offer additional services such as e-commerce, electronic program guides and content synchronized to the TV and radio shows. If these services are to be received by several receiving terminals with different properties, the services must be adapted to the terminals. This can be done by scaling the services, meaning that the appearances and functionality of the services vary depending on the terminals’ properties. In this thesis scalable services are examined from a terminal point of view. Present and future receivers, platforms and possible methods to achieve scalability are presented, and their effects on scalable services are discussed. / TV- och radiosändningar har fram till nyligen endast distribuerats över analoga TV- och radionät och tagits emot av traditionella TV- och radioapparater, men detta håller på att ändras i och med att sändningarna digitaliseras och konvergens sker mellan broadcasting, telekom och datakom. Nu kan även andra terminaler fungera som mottagare, t.ex. en PC med ett digital-TVkort eller ett digital-radiokort. Digital TV och radio erbjuder tilläggstjänster som t.ex. ehandel, tjänster kopplade till radio- eller TV-program och elektroniska programguider. Om samma tjänst ska kunna tas emot på flera olika mottagarterminaler med olika egenskaper, måste tjänsten anpassas efter terminalerna. Detta kan göras genom att skala tjänsten, dvs. utseendet och funktionerna varierar beroende på bl.a. terminalens kapacitet. I detta arbete har terminalaspekterna på skalbara tjänster undersökts. Aktuella och framtida terminaler, plattformar och eventuella skalbarhetslösningar presenteras, och deras påverkan på skalbara tjänster diskuteras.