This dissertation addresses the problem of providing a®ordable mobile mul-timedia services in wide area wireless networks. The approach is to con-sider novel system architectures, based on reusing and sharing of the ex-isting network infrastructure for cellular and terrestrial TV broadcastingsystems. The focus has been on the radio resource management techniques,and the evaluation of the potential cost savings, compared to traditionalevolution tracks of the cellular and broadcasting systems.The studies show that deployment cost of a wide area broadcastingnetwork, using DVB-H technology, is very large if high data rate and fullarea coverage is targeted. For this reason we propose to avoid the broad-casting infrastructure dimensioning for full area coverage, and use insteadthe cellular systems to enable error correction for broadcasting transmis-sions. For the special case of mobile users, the chosen approach is to tradesystem's cost and capacity for improved perceived coverage. This trade-o®is enabled by the use of application layer forward error correction, usingRaptor coding.The general purpose Ambient Networks technology was chosen to en-able a platform for inter-operability between cellular and broadcasting sys-tems, especially the necessary interfaces. Under the Ambient Networksframework, we investigate the achievable cost savings o®ered by a hybridcellular-broadcasting system when combinations of broadcast and point-to-point transmissions are jointly utilized to provide ¯le transfers and stream-ing services. Two cases were investigated: one where the cellular systemacts as a replacement and deliver the data in the areas where broadcastingtransmissions cannot reach, and another one where cellular system carriesparity data to users that experience temporary outage in the broadcastingsystem. The results are encouraging, as they show that ¯le transfer costcan be reduced by more than 50%, but only under certain conditions.On a short term, hybrid cellular-broadcasting systems based on 3G andDVB-H, o®er a good platform for testing new and innovative mobile TVservices, enriched with interactivity and content personalization. From atechnical perspective, the outcomes of the presented studies indicate thatfuture systems built on hybrid cellular-broadcasting infrastructures are ableprovide a long term and cost e±cient solution for delivery of a®ordablebroadband multimedia services to mobile users. However, today's cellularand broadcasting systems live in di®erent worlds, are driven by di®erentrevenue models, and they are now starting to compete, instead of cooperate,for controlling the multimedia delivery channels to mobile users. / QC 20100708

DVB (Digital video broadcasting) is the television digital system. It's however much more than a simple replacement for existing analogue television transmission, this system has many advantages such as picture quality and allows you a range of new features and services including subtitling, multiple audio tracks, interactive content, multimedia content... The system is based in the OFDM technology, which allows DVB system to exploit the spectrum frequencies in a better way, saving spectrum, but OFDM has an important drawback that is the peak to average power ratio problem. OFDM is based on the FFT algorithms generating several orthogonal subcarriers. This thesis talks about the improvement of the PAPR problem using the clipping method. The simulation has been developed in Simulink® and Matlab®. With all the information presented in this thesis, any user can simulate the system. Thus, this thesis can be improved using other using other techniques to solve the PAPR problem.

The first topic of this thesis proposes a digital negative phase shifter circuit which generates a clock with adjustable negative delays (phase shift) in order to avoid multi-locking hazards. Arbitrary negative phase can be generated by using multiplexers and voltage variable delay cells to select the required phase shift. The proposed design is implemented by 0.35 um CMOS 1P4M technology. A single-shot locking method is adopted to reduce the locking time. Most important of all, the negative phase shifter is predictable and adjustable. The simulation results show that the accuracy of the proposed design is better than 6%. The second topic is to describe a 10-bit, 80 MS/s analog-to-digital converter (ADC) for digital video broadcasting over terrestrial (DVB-T) receivers. The ADC is based on a four-channel parallel pipeline architecture which employs dynamic comparators and switch-capacitance sample-and-hold circuit to achieve high speed operation and low power consumption. Simulation results using a TSMC 0.35um 2P4M process show that the proposed ADC achieves 56dB spurious-free dynamic range (SFDR) and 9.01-bit ENOB.

In this thesis, a highly efficient implementation of the channel decoder for terrestrial digital video broadcast (DVBT) standard is proposed. DVB-T channel decoder is mainly composed of four major modules including the inner Viterbi decoder, outer Reed-Solomon decoder and inner and outer de-interleaver modules which all require significant amount of intermediate data storage. The main contribution of this thesis is to propose suitable architectural solution for each individual module to achieve efficient realization of the data storage mostly by single-port memory blocks which can lead to the reduction of silicon area and the dynamic power dissipation. For the outer convolutional deinterleaver module, a special address generator has been proposed such that the data deinterleaver path can be merged and implemented as three memory blocks. For the inner symbol deinterleaver module, a lookahead technique has been applied to the design of address generator that can generate valid deinterleaving address each cycle to avoid the buffering problem. In addition, a novel deinterleaver memory partitioning architecture is proposed such that the entire deinterleaver can be built on four single-port memory banks. These four modules have been verified and integrated as a robust channel decoder silicon intellectual property (IP). Our implementation result shows that the core area of entire DVB-T channel decoder IP (Intellectual Property) can be realized in less than 6.8 mm2 in 0.18-µm TSMC technology.

This research aims to design a dual-conversion tuner RFIC for DVB-H applications with EDA tools. In order to have good understanding of the EDA tools used, both time-domain and frequency-domain simulation techniques are studied and discussed in this thesis. The designed tuner RFIC is implemented by a TSMC 0.35£gm SiGe BiCMOS process. The parasitic effects from PCB interconnects are also considered in this work. We use 3-D quasi-static EM simulation tool to extract the parasitic elements for PCB interconnects, and co-simulate these parasitic elements with RFICs using circuit simulation tool. The implemented tuner RFIC integrates most key components into a single chip, including the variable-gain low noise amplifier, up-converting mixer, intermediate-frequency amplifier, and down-converting mixer. Under QPSK modulation test, the designed tuner RFIC shows a wide dynamic range with good protection ratio. In addition, it has a low power consumption and thus is suitable for use in portable digital TV equipments.

Η διπλωματική εργασία μελετά την παροχή υπηρεσιών ψηφιακής τηλεόρασης (DVB) από πλατφόρμες μεγάλου υψομέτρου (High Altitude Platforms-HAPs). Στο πρώτο κεφάλαιο γίνεται μια εισαγωγή στις δορυφορικές επικοινωνίες κομμάτι των οποίων θεωρούνται και οι στρατοσφαιρικές πλατφόρμες. Στο δεύτερο κεφάλαιο αναλύονται θέματα των πλατφορμών αυτών, όπως τα πλεονεκτήματα και μειονεκτήματα τους σε σύγκριση με άλλα δορυφορικά και επίγεια συστήματα, ο σχεδιασμός του καναλιού, δίκτυα αποτελούμενα από στρατοσφαιρικές πλατφόρμες και οι τομείς στους οποίους αυτά βρίσκουν εφαρμογή. Στο τρίτο κεφάλαιο παρουσιάζεται το πρότυπο δορυφορικής μετάδοσης ψηφιακού βίντεο DVB-S, τα σχήματα διαμόρφωσης και κωδικοποίησης που χρησιμοποιεί, οι απαιτήσεις του αλλά και το πρόσφατο DVB-S2. Στο τελευταίο κεφάλαιο παρατίθενται οι εξομοιώσεις που πραγματοποιήθηκαν στα πλαίσια της εργασίας καθώς και τα αποτελέσματα που λήφθηκαν για διάφορα είδη διαμόρφωσης και για μεταβολή των παραμέτρων του ενδιάμεσου καναλιού. Η εργασία καταλήγει με μια σύντομη σύγκριση του στρατοσφαιρικού συστήματος με ένα επίγειο σύστημα μετάδοσης ψηφιακής τηλεόρασης. / -

Σκοπός της συγγραφής της παρούσας διπλωματικής εργασίας είναι η μελέτη και ο σχεδιασμός της μονάδας συγχρονισμού φάσης σημάτων τεχνολογίας DVB-S2. Ο ρόλος της μονάδας αυτής είναι καθοριστικής σημασίας για την εξασφάλιση της αποδοτικής λειτουργίας των συστημάτων του προτύπου αυτού σε τυπικά δορυφορικά κανάλια. Αρχικά πραγματοποιείται μια εισαγωγή στις βασικές έννοιες και στη δομή ενός δορυφορικού συστήματος και εξετάζονται οι δυσμενείς επιδράσεις της ατμόσφαιρας κατά τη μετάδοση των δορυφορικών σημάτων. Ακολούθως γίνεται παρουσίαση της μετάδοσης τηλεοπτικών προγραμμάτων μέσω δορυφόρου και αναλύονται βασικά χαρακτηριστικά του δορυφορικού προτύπου DVB-S2. Παρουσιάζεται λεπτομερώς η αρχιτεκτονική μετάδοσής του και αξιολογείται η απόδοση του. Σημαντικό τμήμα της εργασίας αποτελεί η μελέτη του συγχρονισμού της παραμέτρου φάσης των λαμβανόμενων σημάτων σε δέκτες ψηφιακών συστημάτων επικοινωνίας. Αφού αναλυθεί η διαδικασία συγχρονισμού και τα χαρακτηριστικά της εκτίμησης της τιμής παραμέτρων των μεταδιδόμενων σημάτων, αναλύονται οι διατάξεις που υλοποιούν το συγχρονισμό φάσης σε σήματα τεχνολογίας DVB-S2 και εκτιμάται η απόδοσης λειτουργίας τους. Στη συνέχεια, περιγράφεται η διαδικασίας ανάπτυξης του μοντέλου υλοποίησης σε υλικό (FPGAs) της παραπάνω μονάδας, αξιοποιώντας το εργαλείο System Generator 10.1 της Xilinx και το περιβάλλον Simulink της Matlab. Τέλος, παρουσιάζεται και αναλύεται η ορθή λειτουργία της σχεδίασης για πραγματικά σήματα DVB-S2. / The purpose of this diploma thesis is the study and hardware implementation of Carrier Phase Recovery Unit for DVB-S2 systems. This operation of this unit of crucial importance complementing outstanding performance results over typical satellite channels. In the first part of this thesis, an introduction on important principles of satellite communications is carried out and the architecture of a satellite communication system is presented. Among others, the aggravating atmospheric effects taking place during satellite transmission are outlined. Afterwards, satellite transmission of television programs is examined and an analysis of the satellite standard DVB-S2 follows. The structural design of the transmission system is stated in detail and the efficiency of this standard is assessed. A substantial part of this work concerns the study of phase synchronization for digital communication receivers. After the theoretical analysis of the synchronization process, the unit implementing phase recovery for DVB-S2 systems is presented and its efficiency is examined for different kinds of distortions. Moreover, the procedure of hardware implementation (on FPGAs) of this unit is discussed, with the use of both Xilinx System Generator 10.1 and Simulink design tools. This thesis is concluded after presenting the efficient operation of the above implementation for real DVB-S2 signals.

This report adresses why the currently used scrambling standard CSA needs a replacement. Proposed replacements to CSA are analyzed to some extent, and an alternative replacement (AES128) is analyzed. One alternative being the CSA3, and the other being the CISSA algorithm. Both of the proposed algorithms use the AES algorithm as a base. The CSA3 combines AES128 with a secret cipher, the XRC, while CISSA uses the AES cipher in a feedback mode. The different utilizations makes CSA3 hardware friendly and CISSA software friendly. The implementation of the Advanced Encryption Standard (AES) is analyzed for a 128 bit key length based design, and a specific implementation is presented.

Zugl.: Braunschweig, Techn. Univ., Diss., 2007

Στην παρούσα διπλωματική εργασία παρουσιάζεται η υλοποίηση του συγχρονισμού ενός δορυφορικού δέκτη τεχνολογίας DVB-S2 με χρήση προϊόντων από την βιβλιοθήκη Xilinx του Simulink της Matllab. Αρχικά εξετάσαμε τη γενική συμπεριφορά ενός δέκτη και στη συνέχεια κατανοώντας τα ιδιαίτερα χαρακτηριστικά της τεχνολογίας DVB-S2, πραγματοποιήσαμε θεωρητική μελέτη του κυκλώματος που θα υλοποιήσουμε. Σαν επέκταση της παραπάνω μελέτης εξηγήσαμε δίνοντας παραδείγματα, για ποιους λόγους σε κάθε σημείο του συγχρονιστή επελέχθη το εκάστοτε υλισμικό-λογισμικό, από θεωρητικής άποψης. Έπειτα μας δόθηκε ένα μοντέλο, το οποίο ήταν υλοποιημένο με προϊόντα από την γενική βιβλιοθήκη (Simulink) της Matllab· στη συνέχεια δημιουργήσαμε ύστερα από διεξοδικά πειράματα και συγκρίσεις ένα μοντέλο, υλοποιημένο με προϊόντα από τη βιβλιοθήκη Xilinx του Simulink της Matllab, με συμπεριφορά ίδια με αυτή του μοντέλου που μας δόθηκε. Τέλος, παρουσιάσαμε μέσω γραφικών παραστάσεων και γραφημάτων τόσο τη σύγκριση της συμπεριφοράς των δυο μοντέλων, όσο και τη λειτουργία και τις ιδιαιτερότητες αυτού καθ’ εαυτού του μοντέλου που δημιουργήσαμε. / In this diplomatic work we present the concretization of timing of satellite receptor of technology DVB-S2 with use of products from the library Xilinx of Simulink of Matlab. Initially we examined the general behavior of receptor and afterwards comprehending the particular characteristics of technology DVB-S2, we realized theoretical study of circuit that we will materialize. As extension of previous study we explained giving examples, for what reasons we chose each hardware-software, from theoretical point of view. Then we were given a model, which was materialized with products from the general library (Simulink) of Matllab; afterwards we created after extensive experiments and comparisons, a model, materialized with products from the library Xilinx of Matllab Simulink, with behavior precisely same with that of model that was given to us. Finally, we presented via graphic representations and illustrations both the comparison of behavior of two models, and the operation and the particularities each one of the models we created.