The European system for digital multi-programme television bysatellite

The general concepts of the system for digital television transmission by satellite developed within the European DVB (digital video broadcasting) project and standardised by ETSI (European Telecommunications Standards Institute) are described. The system, named DVB-S, is intended to provide DTH (direct-to-home) multi-programme TV services in the BSS (broadcasting satellite service) and FSS (fixed satellite service) bands and is addressed to consumer IRDs (integrated receiver decoders), as well as collective antenna systems (SMATV, satellite master antenna TV) and cable television head-end stations, with a likelihood of remodulation. The exploitation of the multiplex flexibility allows the use of the transmission capacity for a variety of TV service configurations. The use of flexible and advanced error protection techniques, based on the concatenation of Reed-Solomon and convolutional codes (with Viterbi decoding), allows optimum adaptation to different satellite transponder characteristics, i.e. bandwidth and power, providing high service quality and availability with small receiving antennas. For example, in climatic zone E (in Europe) on a 33 MHz transponder a data-rate of 38.1 Mbit/s can be transmitted, adequate to provide five standard definition TV programmes (SDTV) or, alternatively three to four enhanced definition programmes (EDTV), while ensuring 99.90% service availability (in the average year) with 50-cm receiving antenna within the 51 dBW EIRP (equivalent isotropic radiated power) service area contour     

Digital video broadcasting

A new kind of “wireless video” is currently entering consumers' homes-digital television. The term digital video broadcasting (DVB) is used as a synonym for digital television in many countries of the world. Whereas one may tend to think that digital television means just a new, digital, form of signal representation not necessarily affecting the information content of what one has always called TV, the truth is that digital television becomes multiple-channel data broadcasting. This article reviews some of the results of the work in the worldwide DVB Project and explains some of the fundamental concepts behind the work of this group. It then concentrates on the terrestrial transmission system (DVB-T) as one example of the many transmission technologies DVB has developed over the last few years. The COFDM modulation scheme which is a key ingredient of DVB-T is described in some detail. The performance of the system is presented. The use of DVB for data broadcasting and the accompanying return channel technologies are explained     

高清DSNG新闻采访卫星车系统集成

青海广播电视台于2011年10月开始建设高清DSNG新闻采访卫星车,现已完成集成验收工作.高清DSNG新闻采访卫星车系统由卫星传输系统和音视频系统两部分组成,着重从链路计算、设备选型、系统构成、技术指标、系统监控等方面介绍了卫星传输系统.     

有线电视广播网结构的发展

分三部分说明有线电视广播网结构的发展。先是扼要介绍早年使用同轴电缆有线电视广播网。着重叙述现行的光纤与同轴电缆混合的有线电视网 HFC;估测光纤在有线电视网应用的发展前途。     

Analysis of satellite broadcasting systems for digital television

The concept of digital direct satellite broadcasting (D-DBS), which allows unprecedented flexibility by providing a large number of audio-visual services, is introduced. The concept assumes an information rate of about 40 Mb/s, which is compatible with practically all present-day transponders. After discussion of the general system concept, the optimization procedure is introduced, and results of the transmission system optimization are presented. Channel distortion and uplink/downlink interference effects are taken into account by means of a time domain system computer simulation approach. It is shown, by means of link budget analysis, how a medium-power direct-to-home TV satellite can provide multimedia services to users equipped with small (60-cm) dish antennas     

Possible channel coding and modulation system for the satellite broadcasting of a high-definition television signal

A new coding/modulation approach is considered to improve service availability of digital high-definition television (HDTV) satellite broadcasting services at 22 GHz. This approach uses a concept of layered modulation in conjunction with layered picture coding and channel coding. By means of this technique, the service continuity can be extended without the needs for increasing the satellite transmission power, the service quality under severe atmospheric attenuations being reduced from high definition to normal definition.     

Digital television terrestrial broadcasting

Digital transmission will change the way television channels are allocated and will force broadcasters to master a new set of parameters for optimizing service coverage. This article discusses modulation and channel coding issues related to digital television terrestrial broadcasting (DTTB), such as data throughput, spectrum efficiency, single- and multicarrier modulations, interferences under simulcasting conditions, multilayer services, and DTTB coverage. Current advanced television (ATV) research for terrestrial broadcasting in the VHF/UHF bands is converging toward a fully digital implementation. In a digital ATV system, the digitized high definition video sources, with raw bit rate of up to l-Gb/s, are compressed using source coding techniques based on the discrete cosine transform (DCT) coding. The output data rate of the video source encoder, with present technology, is typically 15 to 20 Mb/s. This data rate is sufficient to provide a satisfactory distribution quality video service     

Digital audio broadcasting: High-grade service quality through on-board processing techniques

A digital audio broadcasting (DAB) satellite system is presented here which provides a high-grade quality of service for some hundreds of channels. This, with minimum cost of the radio set and of the broadcasting station, greatly improves the radio broadcasting service throughout the world, especially in areas where deployment of conventional relay infrastructure is difficult and not yet cost-effective. Potential broadcasters located in the visible hemisphere can directly up-link their programming to the DAB satellites. Broadcasters can also copy each up-link channel and steer flexibility to any beam or combination of satellite beams. The paper illustrates the advantages and the feasibility of a DAB system based on geostationary satellites with on-board processing generating signals of MCPC (multiple channel per carrier) type. This multiplexing technique allows large system margins. This solution allows the satellite L-band TWTA amplifiers to be operated in saturation and eliminates the intermodulation noise associated with the transmission of FDMA channels. A powerful coding scheme has been selected to create a ‘robust’ down-link. In this way several high-power DAB channels of radio programming, with selectable data rate, are directly delivered to the users.     

Satellite Direct-to-Home

An overview of satellite direct-to-home (DTH) digital television in the Americas is presented, including history, service applications, and a reference architecture identifying key system building blocks. Satellite DTH's relationship to and differences from terrestrial ATSC are highlighted. The paper concludes with notes on the technology evolutions that allowed the introduction of digital DTH satellite service and contribute to its continued growth today.     

Commercial satellite broadcasting for Europe

A review is presented of the current television broadcasting situation in European countries, which involves a varied mix of terrestrial VHF or UHF systems and cable networks. A small market has emerged in Europe for receivers using the low-power telecommunications satellite transmission between the program providers and cable network companies. This is expected to change with the launch of medium-power pan-European telecommunication satellites (e.g. ASTRA, EUTELSAT II), which are now directly addressing the market of home reception. DBS (direct broadcast satellite) in the UK, using the D-MAC transmission standard, will offer three additional television channels, data broadcasting services, and a planned evolution to compatible forms of wide-screen, high-definition television. Comments are given on receiver and conditional access system standardization. Some views are expressed on satellite broadcasting as part of an overall broadcasting framework for the future     

基于DTMB的多屏互动业务技术模式探析

地面无线广播技术一直是广播电视传输覆盖、实施公共服务的主要手段之一,面对智能终端的快速普及,本文提出了一种基于地面数字电视广播的多屏互动业务技术模式,能够充分利用现有宝贵的无线频率资源,实现视频服务由面向电视机或接收机单一终端到面向电视机、笔记本电脑、平板电脑、智能手机等多终端的扩展,实现地面数字电视广播的跨屏融合应用。     

无线移动新闻采集回传系统设计及其应用

新闻的时效性是新闻报道的首要因素,由于新闻发生时间和地点的不确定性,特别是突发的公共事件需要在最快时间将现场画面传回电视中心,需要有一套高灵活性的传输设备以适用于应急新闻采集及移动状态下的直播。DTNG(Digital Terres-trial News Gather)技术目前已成功应用于F1赛事等专业领域,提出了一种基于该技术的DTNG网络的系统构建,并给出该系统的若干实际应用案例。     

CD by radio-digital radio broadcasting

Engineers have been looking at ways of broadcasting a digital radio service to the general public, which would ideally have the following features: sound quality comparable with that of the CD; reliable reception to all listeners in the coverage area; capability of offering coverage of all listeners; capability of fixed, mobile and portable reception using simple low grains antennas; simple push-button programme selection-no tuning; frequency efficiency, so that many services can be provided in any spectrum available; and capability of operation from terrestrial transmitters and/or satellite. The author describes the requirements of a digital audio broadcasting system regarding intersymbol interference and then discusses COFDM, coded-orthogonal frequency division multiplex. The author also discusses low-bit-rate sound, terrestrial transmission, satellite broadcasting, receivers, frequency allocation and system testing     

Satellite broadcasting in Australia

The operational features of the Australian domestic satellite system, AUSSAT, are discussed, particularly as they relate to broadcasting direct to communities and distribution to transmitters and studio centres of the Australian Broadcasting Corporation, ABC (Aus). Distribution of sound-only broadcasting programs is covered by the use of time-multiplexing using B-MAC. Comprehensive direct broadcasting from satellites is now available to many people living in remote areas of Australia who would otherwise receive minimal service. Initially, for each of the four major regions, ABC (Aus) has provided one television channel with stereophonic sound capability together with three different sound-only services, one of which is stereophonic. In addition to the `free' services of ABC (Aus), commercial broadcasting satellite services are being progressively introduced to the four regions     

Co‐ordination channels for digital satellite news gathering (DSNG)

This paper presents, in Section 1, a new approach to realising co‐ordination channels for digital satellite news gathering (DSNG). The key element of the approach to the co‐ordination channels is a direct‐sequence spread‐spectrum processing of the data to be transmitted which allows for the realization of an in‐band transmission of the co‐ordination channel signals overlaying the DSNG main channel, the part of the system which is responsible for the transmission of the audio/video signal on a point‐to‐point basis. The system is analysed in theory, simulation, and measurement with respect to system performance and degradation of the DSNG main channel. It shows superior system performance combined with a maximum of operational simplicity while the degradation of the DSNG main channel remains affordably low. Section 2 describes the DVB‐DSNG system for co‐ordination channels which incorporates many elements of the system presented in the first part but is modified in some details in order to increase system flexibility. One of these details concerns the possibility to perform in‐band transmission as well as transmission in the roll‐off frequency space of the DSNG main channel. In‐band transmission has the advantage of great operational simplicity and is nearly identical to the system presented in Section 1. What characterizes the transmission in the roll‐off frequency space is the fact that it is more robust and DSNG main channel degradation is negligible, but this at the price of decreased operational simplicity. Copyright © 2000 John Wiley & Sons, Ltd.     

Layered space–time block code for hybrid satellite–terrestrial broadcasting systems

Multiple‐input multiple‐output (MIMO) is a topic of high interest for the next generation of broadcasting systems. Even if they have begun to be proposed for the second generation of terrestrial digital TV, there are still gaps in the deployment of MIMO schemes in single‐frequency networks. This deployment becomes more critical when a hybrid satellite–terrestrial transmission is adopted because of the different aspects of the respective transmission links. In this paper, we propose to apply a layered space–time block code (LSTBC) for MIMO schemes in this hybrid transmission for next‐generation handheld (NGH) systems. The contribution of this paper is multi‐fold. First, we detail the land mobile satellite channel specifications describing the satellite link. Then, we propose to apply a MIMO scheme between the antennas of the satellite site and the terrestrial site. Then, we introduce the LSTBC scheme for NGH broadcasting systems. The proposed code is based on a layered construction designed to be efficient in shadowing regions. This efficiency is verified in a line‐of‐sight situation but also in low, moderate and deep shadow situations. The LSTBC scheme is then a very promising candidate for NGH systems with MIMO transmission. Copyright © 2012 John Wiley & Sons, Ltd.     

Testing of digital television broadcasting from the stratosphere

Digital TV broadcasting from the stratosphere was tested using an unmanned aerial vehicle, a Pathfinder Plus. A television transmitter installed under the wing transmitted a UHF band signal as the vehicle flew at an altitude of 20 km. The Japanese digital terrestrial broadcasting standard (ISDB-T) was used for transmission. The 13.5-hour flight time included 3 hours of transmission testing. The transmitting equipment worked as expected in spite of the cold and low-atmospheric-pressure environment. Reception at the ground station was satisfactory even when the ISDB-T parameter set used was the one least robust under poor channel conditions.     

Maximizing service availability for secure satellite broadcasting

Cryptography is the most suitable technique to protect the access to subscribed value‐added services for mobile applications provided through satellite broadcasting (e.g. localization and mobile TV). However, if a temporary loss of signal is experienced by receivers, not only the data streaming is compromised, but also the key management‐related messages. Hence, when the signal is received again, it is impossible for the receivers to decrypt it. One way to overcome this issue is the re‐transmission of keys to guarantee that the largest set of legitimate receivers has the updated (set of) keys. In this paper we analyze the problem of key update in a mobile user context in order to maximize the service availability. In particular, we provide the following contributions: we propose a mathematical model that captures all the relevant features of mobile users. Then, we formally prove a few novel results on the structure of the admissible rekeying sequence. These results are used to design a scheduling algorithm for key broadcasting that, according to our model, minimizes the number of mobile users that are prevented from updating their crypto keys, hence continuing accessing the service. Finally, simulation results support our theoretical findings. Copyright © 2008 John Wiley & Sons, Ltd.     

数字电视数字广播技术与传输标准探析

当前数字电视数字广播技术为我国电子技术领域带来了新的影响,为模拟信号向数字信号转换提供技术支持。使用数字电视技术对信号进行处理与分析,有效保证了数字信号传输的安全性。根据数字电视数字广播传输的标准需求,并结合国家标准的系统框架处理流程,对关键技术的细节进行研究,并对数字电视数字广播传输的相关问题进行探析。     

Introduction to special issue on satellite broadcasting

A review is presented of the present status and the future of satellite broadcasting as well as the state of the art of direct-broadcast-satellite (DBS) technology, including the earth station. Satellite, TV program reception in various countries of the world is roughly classified into; (1) TV broadcasting services by means of a broadcasting satellite, and (2) reception of TV programs from communication satellites. In this context the author discusses the conditions covering satellite TV reception and the existing and planned services for Europe, North America, Asia, and the Middle East