Know the DVB Standard Preliminary

Know the DVB StandardPreliminary
At this time we can say that the entire broadcasting chain starting from the production process to distribution of digital television has been done, but the last chain of transmission process to end-users are still largely conducted in analog. DVB (Digital Video Broadcast) is one of the systems used to transmit digital TV broadcasting until the end-user.
DVB development effort as a global standard for digital television broadcasting either via satellite or terrestrial originated from the formation of the DVB Project in 1993. DVB Project consists of approximately 250 institutions from 30's, country and consists of broadcasters, manufacturers, network operators, regulatory bodies and academic institutions. DVB Project does not perform the function as a regulator but a work based on business and commercial aspects.
In a further development of the DVB Project has successfully developed a series of DVB specifications are not limited to video broadcasting, but also has penetrated down to the applications and multimedia services.
This paper will try to give a bit of an idea of ​​the DVB standard. Given the breadth and depth of DVB standards, this article can not possibly cover everything. For those readers who are interested to know more about DVB can read a variety of references are available, including through http://www.dvb.org or http://www.etsi.org.Why DVB
DVB was developed based on the background of the importance of broadcasting system which is open (open system) which is supported by the ability of interoperability, flexibility and commercial aspects. As an open system, the DVB standard can be used by vendors to develop a variety of innovative services and value-added services that are compatible with each other DVB devices from other vendors. In addition, digital programs transmitted by the DVB specifications can be transferred from one transmission medium to another transmission medium with a cheap and easy. The approach taken by the DVB is to maximize the existing tools and common system available in the commercial market.
With digital technology, DVB can utilize bandwidth more efficiently. One satellite transponder that is usually only used for one analog TV program, using the DVB can be used to broadcast the 8 channel digital TV. Besides the addition of a TV channel capacity, the terrestrial transmission media can be obtained better image quality and even the media cable TV, DVB-C offers two-way interaction.
One of the fundamental decisions taken in setting standards is the selection of DVB MPEG-2 as "data containers". With these conceptions of the transmission of digital information can be flexibly without the need to provide limits what type of information will be stored in "data container" is. Selection of MPEG-2 compression system for coding and done because it proved that MPEG-2 capable of providing good quality according to available resources. From a commercial standpoint, the adoption of MPEG-2 which is the standard of existing and proven very beneficial because it allows DVB to concentrate on its efforts in finding ways to package the MPEG-2 data packets through different transmission including satellite, cable, SMATV, LMDS, as well as terrestrial. Chip-sets for coding and decoding MPEG-2 has been commercially available so that the price of the decoder in the commercial market priced. However because the MPEG-2 contained in the ISO document is generic, then the DVB Project developed a document that contains restrictions on the syntax and parameters of MPEG-2 and recommended values ​​used in DVB applications.
DVB Service future will consist of various types of programs developed through a number of transmission channels. For IRD to ditune for certain services automatically through a user friendly navigation system then adds a navigation aid DVB DVB-SI (Service Information) which is an extension of the Programme Specific Information (PSI) from MPEG-2. Service information in DVB serves as the header of the MPEG container so that the receiver can find out what it takes to decode the signal.
In addition, MPEG-2 decoder enables a flexible design as improving the quality of the encoding. Any increase in performance due to the development of new encoding system will be automatically reflected on the image quality of the decoder.Transmission
DVB standards can be applied to a variety of media ranging from satellite transmission (DVB-S), cable (DVB-C) or terrestrial radio waves (DVB-T).Standard DVB-S DVB Project is the first product that allows the delivery of DVB signals via satellite. The document describes the various tools for purposes including the implementation of the modulation channel pengkodingan Binary Phase Shift Keying (BPSK).Channel coding and modulation systems DVB on cable systems (CATV) is described in the document DVB-C standard. This document is the basis for further development for the specification of [DVB-CS is used, (Satellite) Master Antenna TV (SMATV).DVB also regulates the use of terrestrial transmission media in DVB-T specification. Utilization of microwaves for transmission via DVB MMDS (Multichannel Microwave Distribution System) can be divided into two specifications: for the MMDS frequencies above 10 GHz (DVB-MS) using DVB-S specification, while for frequencies below 10 GHz (DVB-MC) is primarily based on DVB-C.Conditional Access System
CAS (Conditional Access System) is a subsystem that serves as control access to programs or services that are able to receive just service users who have received authorization. CAS consists of several blocks of which mechanism to scramble the program or service, Subscriber Management System (SMS), Subscriber Authorization System (SAS), etc.. SMS is essentially a data base containing customer information of a service, while the SAS function encrypt and send the code-words that enable the IRD to mendescrambler a program. DVB Project is not to make CAS as part of the DVB standard. However DVB Common Scrambling Algorithm developed a, namely tools for scrambling Transport Streams or Program Streams Elementary. DVB liberate the use of types of CAS in accordance with the needs of operators from multiple vendors DVB members that offer a competitive commercial product.In addition to the DVB standard allows the occurrence of cross-medium interoperabillity which allows various different delivery media can be interoperable with each other, one aspect of interoperability is that all DVB-compliant devices from different vendors can easily connect to each other in a broadcast chain.However integrated receiver decoders (IRD), which uses a different Conditional Access technology may not always be interoperable with each other. There are two approaches by DVB for the occurrence of interoperating between various different CAS, namely:

    * SimulCrypt, in this case some programs to negotiate commercial providers to enable users who already have a proprietary CAS IRD with embedded in them can enjoy the different services of the CAS due to supply the necessary proprietary information.
    * Multicrypt, CAS technologies can be on one platform so that the same IRD can receive dibroadcast programs simultaneously from several different programs CASnya.
Interactivity
DVB system has the ability to utilize the return path between the IRD and the Service Provider via the module's Subscriber Management System. For the purposes of this return path is required modem and telephone or cable TV networks return path or even a satellite uplink. Return this path can be used to send signals back from the user as the application televoting, playing games, tele-shopping, and tele-banking, and also to send commands browsing on an internet website. Despite the limited bandwidth for the return path is not suitable for sending video images to move from house to broadcasters, the next stage of development is expected to allow for this to happen. In addition, DVB also offers a kind of interactivity without requiring a return path that is providing a variety of program choices according to user choice.
Many services are offered in DVB will require some form of interaction between the user and the program provider or network operator. This interaction can be a bit of a command transmission but may also require fairly intensive interaction as in communication via the Internet. Interactive TV identified as one of the important keys that will control the digital transmission system in the future. Various members of the DVB has developed a comprehensive plan for the introduction of interactive TV since 1997. The occurrence of convergence in this area allow for a turning point in the future world of broadcasting.Various specifications of the DVB return channel has been published by ETSI including the DVB-RCC (Cable) and DVB-RCT (Telephone or ISDN), which is the complement of the DVB-NIP (Network Independent Protocols) are based on MPEG-2 DSM-CC (Digital Storage Media-Command and Control).DVB allows the occurrence of these interactions and specify two types of tools for that purpose. The first is interatif tools that are network-independent which can be regarded as a layer 2 or three in the protocol stack of ISO / OSI protocol derived from the Digital Storage Media Command Control (DSM-CC) of MPEG.The second group is associated with a lower layer (layer 1 or two) of the OSI model / ISO in the form of interactive tools that are network-dependent. There are several specifications that have been developed, among others, through the Public Switched Telephone Networks (PSTN) and Integrated Services Digital Networks (ISDN). It also developed a comprehensive solution for interaction through a network of CATV, Hybrid Fibre Coaxial (HFC), Terrestrial Systems, Satellite Master Antenna Television Systems (SMATV), LDMS, VSAT, DECT, and GSM.Interoperability
DVB systems are designed to make the most common elements in the commercial market. This allows starndard used in distributing the signal without having to perform complicated processes in the process of decoding and re-coding from one medium to another. Interoperability between standards allows manufacturers to achieve economies of scale. Most of the same element used in all sisytem. The following diagram illustrates a common sequence found on the DVB IRD.Development of DVB
Results achieved by the DVB Project in the form of a comprehensive document both technical and non-technical, describing the solutions needed by the players in the market to utilize digital technology in the field of broadcasting. Since receipt of DAVIC (Digital Audio-Visual Council) as the central coordinating agency for the aspects of digital media convergence, DVB has been working together in terms of determining the technical and operational solutions in the development of various multimedia transmission media. Many of the DVB system is accepted as standard DAVIC. What was done by the DVB and DAVIC has expanded from merely broadcasting aspects towards the development of end-to-end interoperability. DVB system with MPEG-2 as the core video coding scheme, audio and data can be used to pack all kinds of formats used for multimedia purposes either in the form of text, images, graphics, and various types of moving image allows multimedia extensions added at the time of its appearance, but the noteworthy is that the key principal of the DVB is "broadcasting", so that the focus of the development of DVB is for commercial broadcasting market. System for DVB relatively new technology vendors, broadcasters and network providers. One of the strengths of the DVB technology lies in the fact that DVB allows transmission some sizzle data at high speed point-to-multipoint in a manner that is safe from the possibility of transmission errors. To enable the transmission of data in question includes the possibility of repetition of the same data transmission at a fixed time interval or not fixed, the DVB has developed a specification for data broadcasting .
Although the DVB project has reached the stage of maturity, but a variety of activities such as development continues, the development of solutions to membroadcast DVB High Definition Television (HDTV), Specification for Digital Satellite News Gathering (D-SNG), specifications for the interface that will connect the world with DVB networks PDH, ATM and SDH managed by telecom network operators, etc.. q
Dudy Effendi, IPStaff of the Directorate of Planning and Technology, PT. Telekomunikasi IndonesiaDepartment of Physics ITB alumni and the School of Information Science University of Pittsburgh.