Digital Audio Broadcasting: Technology and Prospects

The subject of the thesis was the digital audio broadcasting technology developed in the Eureka project 147. The research was based on the literature on the subject. At first, some reasons for the digitisation of broadcasting technology were given. Next, the channel multiplexing and channel coding methods employed by digital radio were discussed. The design of these methods is based on certain phenomena related to the propagation of radio-frequency signals, and these phenomena were also described. After that, audio and data transfer mechanisms as well as the structure of digital radio network were explained. Furthermore, digital audio and data services were considered. Finally, the digital radio was examined from marketing and administrative aspects. From a merely technical point of view, the digital radio technology offers several improvements in comparison with analogue technology. However, the digital radio has not become as widespread as it was perhaps originally expected during its development.

Avalon Media System project update: a Hydra solution for digital audio and video access

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Digital Video Broadcasting: Introduction

Versione preliminare per la lezione del 28/02/2008

I sistemi di diffusione multimediali: il Digital Video Broadcasting (DVB)

In questo elaborato, dopo una descrizione delle procedure per la creazione degli standard per il il broadcasting numerico adottate dal DVB forum, vengono presi in considerazione i trends del mercato del broadcasting numerico e analizzato in dettaglio lo standard utilizzato per la diffusione televisiva terrestre DVB-T e la sua evoluzione DVB-T2.

Report on copyright implications of digital audio transmission services : a report of the register of copyrights.

Accompanied by "Appendix--comment letters, docket RM 90-6" (ix, 615 p. ; 28 cm.).

Playing with sound and gesture in digital audio games

This article introduces the genre of a digital audio game and discusses selected play interaction solutions implemented in the Audio Game Hub, a prototype designed and evaluated in the years 2014 and 2015 at the Gamification Lab at Leuphana University Lüneburg.1 The Audio Game Hub constitutes a set of familiar playful activities (aiming at a target, reflex-based reacting to sound signals, labyrinth exploration) and casual games (e.g. Tetris, Memory) adapted to the digital medium and converted into the audio sphere, where the player is guided predominantly or solely by sound. The authors will discuss the design questions raised at early stages of the project, and confront them with the results of user experience testing performed on two groups of sighted and one group of visually impaired gamers.

Maston ympärille asennetun antenniryhmän säteilykuvion laskeminen

Tämän insinöörityön tavoitteena oli tehdä MATLAB-sovellus, jolla voidaan laskea ja tulostaa yleisradiotoiminnassa käytettävien dipolipaneeliantennien säteilykuvioita. Toinen tavoite oli saattaa tämän työn valvojan Antti Koivumäen vuoden 1980 diplomityön laskenta ja grafiikka modernimmalle tasolle. Aluksi työssä tarkasteltiin yleisiä asioita VHF- ja UHF-taajuuksien lähetystavoista ja lähetinantennityypeistä. Alussa käytiin läpi myös antennijoukon ja -ryhmän käsite. Seuraavaksi tutustuttiin tarkemmin lähetinantennien rakenteeseen ja ominaisuuksiin. Antennien ominaisuuksista tarkasteltiin säteilykuviota, suuntaavuutta, vahvistusta, hyötysuhdetta ja polarisaatiota. Näistä säteilykuvio oli tarkimman tutkinnan kohteena. Säteilykuvion laskeminen esitettiin kaavojen ja havainnoillistavien kuvien avulla. Lopuksi perehdyttiin antennin säteilykuvion laskemiseen tietokoneella, etenkin MATLABilla. Osuudessa tarkasteltiin graafisen käyttöliittymän tekemistä, laskennan suorittamista ja horisontaalisen säteilykuvion esittämistä graafisesti. Työn tuloksena saatiin tehdyksi MATLAB-sovellus, joka laskee elementtiantennin horisontaalisen säteilykuvion annettujen parametrien avulla ja tulostaa sen.

Sistemi OFDM: prestazioni di livello fisico

I primi studi su Orthogonal Frequency Division Multiplexing (OFDM) sono stati fatti fin dal 1960, ma negli ultimi anni la modulazione OFDM è emersa come una tecnica di modulazione chiave commerciale per i sistemi di comunicazione ad alta velocità. La ragione principale di questo crescente interesse è dovuto alla sua capacità di fornire dati ad alta velocità impiegando sistemi con complessità bassa e contrastando l'interferenza intersimbolo (ISI) e quella intercanale (ICI). Per questo motivo la modulazione OFDM è stata adottata da diversi sistemi digitali wireline e wireless standard, come Digital Audio Broadcasting (DAB), Asymmetric Digital Subscriber Line (ADSL), Wireless Local Area Network (IEEE 802.11 a,g,n) oppure per WiMAX e LTE.

On Transmission System Design for Wireless Broadcasting

This thesis considers aspects related to the design and standardisation of transmission systems for wireless broadcasting, comprising terrestrial and mobile reception. The purpose is to identify which factors influence the technical decisions and what issues could be better considered in the design process in order to assess different use cases, service scenarios and end-user quality. Further, the necessity of cross-layer optimisation for efficient data transmission is emphasised and means to take this into consideration are suggested. The work is mainly related terrestrial and mobile digital video broadcasting systems but many of the findings can be generalised also to other transmission systems and design processes. The work has led to three main conclusions. First, it is discovered that there are no sufficiently accurate error criteria for measuring the subjective perceived audiovisual quality that could be utilised in transmission system design. Means for designing new error criteria for mobile TV (television) services are suggested and similar work related to other services is recommended. Second, it is suggested that in addition to commercial requirements there should be technical requirements setting the frame work for the design process of a new transmission system. The technical requirements should include the assessed reception conditions, technical quality of service and service functionalities. Reception conditions comprise radio channel models, receiver types and antenna types. Technical quality of service consists of bandwidth, timeliness and reliability. Of these, the thesis focuses on radio channel models and errorcriteria (reliability) as two of the most important design challenges and provides means to optimise transmission parameters based on these. Third, the thesis argues that the most favourable development for wireless broadcasting would be a single system suitable for all scenarios of wireless broadcasting. It is claimed that there are no major technical obstacles to achieve this and that the recently published second generation digital terrestrial television broadcasting system provides a good basis. The challenges and opportunities of a universal wireless broadcasting system are discussed mainly from technical but briefly also from commercial and regulatory aspect

RRNS-convolutional encoded concatenated code for OFDM based wireless communication

The modern telecommunication industry demands higher capacity networks with high data rate. Orthogonal frequency division multiplexing (OFDM) is a promising technique for high data rate wireless communications at reasonable complexity in wireless channels. OFDM has been adopted for many types of wireless systems like wireless local area networks such as IEEE 802.11a, and digital audio/video broadcasting (DAB/DVB). The proposed research focuses on a concatenated coding scheme that improve the performance of OFDM based wireless communications. It uses a Redundant Residue Number System (RRNS) code as the outer code and a convolutional code as the inner code. The bit error rate (BER) performances of the proposed system under different channel conditions are investigated. These include the effect of additive white Gaussian noise (AWGN), multipath delay spread, peak power clipping and frame start synchronization error. The simulation results show that the proposed RRNS-Convolutional concatenated coding (RCCC) scheme provides significant improvement in the system performance by exploiting the inherent properties of RRNS.

Study of the audio coding algorithm of the MPEG-4 AAC standard and comparison among implementations of modules of the algorithm

Audio coding is used to compress digital audio signals, thereby reducing the amount of bits needed to transmit or to store an audio signal. This is useful when network bandwidth or storage capacity is very limited. Audio compression algorithms are based on an encoding and decoding process. In the encoding step, the uncompressed audio signal is transformed into a coded representation, thereby compressing the audio signal. Thereafter, the coded audio signal eventually needs to be restored (e.g. for playing back) through decoding of the coded audio signal. The decoder receives the bitstream and reconverts it into an uncompressed signal. ISO-MPEG is a standard for high-quality, low bit-rate video and audio coding. The audio part of the standard is composed by algorithms for high-quality low-bit-rate audio coding, i.e. algorithms that reduce the original bit-rate, while guaranteeing high quality of the audio signal. The audio coding algorithms consists of MPEG-1 (with three different layers), MPEG-2, MPEG-2 AAC, and MPEG-4. This work presents a study of the MPEG-4 AAC audio coding algorithm. Besides, it presents the implementation of the AAC algorithm on different platforms, and comparisons among implementations. The implementations are in C language, in Assembly of Intel Pentium, in C-language using DSP processor, and in HDL. Since each implementation has its own application niche, each one is valid as a final solution. Moreover, another purpose of this work is the comparison among these implementations, considering estimated costs, execution time, and advantages and disadvantages of each one.

A implantação da televisão digital terrestre na Espanha

This monograph has as objectives introduce digital terrestrial television, describing the process of installation of this in Spain, their technical qualities and possibilities of change and innovation that this creates. The exposure of the different chapters of this monograph has a objective presenting and discussing what are the characteristics of this new technology, your birth, what is its importance in communication and how this is inserted inside the Spanish reality. The introduction of digital terrestrial television in Spain is cited as an example of a pioneer in the development and installation of this new technology, but also appears as a nation that has come a way with some economic failures, reaching one of the largest cases of delayed installation of digital television in Western Europe. Making use of the European system for digital terrestrial television (DVB-T - Digital Video Broadcasting) it was possible some advances as the quality of communication and strengthening national public television system, but many vices of analog system were transferred this new system, as the concentration of channels to a foreign group and interactivity opportunities were wasted. Digital terrestrial television can provides better picture quality and sound, possibility of interactivity, mobility, hypermedia and multiprogramming, while the latter tool may lead to the democratization of media, opening it to other social agents. Going much further than just a technological advancement, digital television is strongly connected with the politics and the economy of the nation in which it operates

Packet Level Coding for Mobile Broadcasting

The thesis deals with channel coding theory applied to upper layers in the protocol stack of a communication link and it is the outcome of four year research activity. A specific aspect of this activity has been the continuous interaction between the natural curiosity related to the academic blue-sky research and the system oriented design deriving from the collaboration with European industry in the framework of European funded research projects. In this dissertation, the classical channel coding techniques, that are traditionally applied at physical layer, find their application at upper layers where the encoding units (symbols) are packets of bits and not just single bits, thus explaining why such upper layer coding techniques are usually referred to as packet layer coding. The rationale behind the adoption of packet layer techniques is in that physical layer channel coding is a suitable countermeasure to cope with small-scale fading, while it is less efficient against large-scale fading. This is mainly due to the limitation of the time diversity inherent in the necessity of adopting a physical layer interleaver of a reasonable size so as to avoid increasing the modem complexity and the latency of all services. Packet layer techniques, thanks to the longer codeword duration (each codeword is composed of several packets of bits), have an intrinsic longer protection against long fading events. Furthermore, being they are implemented at upper layer, Packet layer techniques have the indisputable advantages of simpler implementations (very close to software implementation) and of a selective applicability to different services, thus enabling a better matching with the service requirements (e.g. latency constraints). Packet coding technique improvement has been largely recognized in the recent communication standards as a viable and efficient coding solution: Digital Video Broadcasting standards, like DVB-H, DVB-SH, and DVB-RCS mobile, and 3GPP standards (MBMS) employ packet coding techniques working at layers higher than the physical one. In this framework, the aim of the research work has been the study of the state-of-the-art coding techniques working at upper layer, the performance evaluation of these techniques in realistic propagation scenario, and the design of new coding schemes for upper layer applications. After a review of the most important packet layer codes, i.e. Reed Solomon, LDPC and Fountain codes, in the thesis focus our attention on the performance evaluation of ideal codes (i.e. Maximum Distance Separable codes) working at UL. In particular, we analyze the performance of UL-FEC techniques in Land Mobile Satellite channels. We derive an analytical framework which is a useful tool for system design allowing to foresee the performance of the upper layer decoder. We also analyze a system in which upper layer and physical layer codes work together, and we derive the optimal splitting of redundancy when a frequency non-selective slowly varying fading channel is taken into account. The whole analysis is supported and validated through computer simulation. In the last part of the dissertation, we propose LDPC Convolutional Codes (LDPCCC) as possible coding scheme for future UL-FEC application. Since one of the main drawbacks related to the adoption of packet layer codes is the large decoding latency, we introduce a latency-constrained decoder for LDPCCC (called windowed erasure decoder). We analyze the performance of the state-of-the-art LDPCCC when our decoder is adopted. Finally, we propose a design rule which allows to trade-off performance and latency.

MHP Oriented Interactive Augmented Reality System for Sports Broadcasting Environments

Television and movie images have been altered ever since it was technically possible. Nowadays embedding advertisements, or incorporating text and graphics in TV scenes, are common practice, but they can not be considered as integrated part of the scene. The introduction of new services for interactive augmented television is discussed in this paper. We analyse the main aspects related with the whole chain of augmented reality production. Interactivity is one of the most important added values of the digital television: This paper aims to break the model where all TV viewers receive the same final image. Thus, we introduce and discuss the new concept of interactive augmented television, i. e. real time composition of video and computer graphics - e.g. a real scene and freely selectable images or spatial rendered objects - edited and customized by the end user within the context of the user's set top box and TV receiver.