text] Beijing Radio Digital Multimedia Broadcasting Case Title Describes

Beijing People's Radio Technology Center

First, the background of the project proposed

For the positive response to the State Administration of Radio on radio and TV media, the overall digital strategy deployment, the digital broadcasting technology, especially digital multimedia broadcasting technologies are developing the technology bottlenecks, speed up the small range of digital multimedia broadcasting technology to the actual market test applications and promotion, Beijing People's Radio, Academy of Broadcasting Science, Communication University of China jointly undertake the "Digital Multimedia Broadcasting application of technology in the -band" technology project tasks.

Project overall objective is: to DAB mobile multimedia broadcasting technology in the application of III-band, tracking the international terrestrial digital multimedia broadcasting technology and its development, construction of the regional trial network broadcast. In the system platform can be different source coding, channel coding parameters of business and the combination test, optimize system configuration, network technology program of the research work, and using test data obtained and conclusions, the final completion of initial operational capability with Experimental demonstration of multimedia broadcasting network.

Launch of the project will produce the following three aspects of social and economic benefits:

1, digital multimedia broadcasting technology represents the direction of the development of digital broadcasting, will greatly promote the upgrading of our radio technology.

The early days of digital broadcasting technology to deliver a digital audio signal, and later as the technology continues to evolve, the digital broadcasting transmission in addition to traditional voice signals only, but also can be sent, including audio, video, data , text, graphics and other multimedia signals, including, the development of digital broadcasting to digital multimedia broadcasting is the inevitable development of broadcasting technology.

2, promote the use of digital multimedia technology will drive the broadcast media and related industrial restructuring, the national information and meet the objective requirements of economic development.

Digital broadcasting in particular the era of digital multimedia broadcasting radio practitioners to provide a digital platform, any digital information can pass through this system, which makes the traditional sense of the radio single " Hearing "The media has become dominated by auditory channel, both channels of the integrated visual media, from a technical level, to expand the operating space of traditional broadcast media possible. Meanwhile, as digital multimedia broadcasting technology popularization and application, will lead the program of production, the advertising, receive module development and production of different types of receiving equipment production and sales of many industries, which means that a number multimedia broadcasting technology as the core of the industry chain is emerging.

3, digital multimedia broadcasting technology and the promotion will greatly meet people's diverse selection of modern life.

As the people's living standards, requirements of electronic media to provide high-quality, high-level audio and video programs. Digital multimedia broadcasting technology and to promote to audiences with more choices, providing the programs not only meet the recreational needs of the people, but also can provide more valuable information on specific releases, such as financial information, real-time traffic road, utility consumption information for the convenience of the people's material life, rich cultural life will have a positive meaning.

Second, technical program profiles 1, for different business types defines two different modes of transmission: stream mode and packet mode, flow model: from source to destination, current mode to a fixed bit rate, in a transparent manner within the specified subchannel transmission Package mode: single subchannel in the number of data services within the transportation component of the definition. Within each sub-channel can transmit one or more business components.

Whether it is MPEG audio layer II, encoded DAB audio services or use H.264/MPEG-4AVC the DMB video service is a fixed rate with the frame synchronization bit stream for transmission using current mode .

Microsoft WM and other header control with some fluctuations in the actual rate of DMB video and data services for business use packet mode transmission.

2, the audio business source coding (MUSICAM coding) technology, using psycho-acoustic model, the subjective quality and bit-rate size, processing time required for encoding and decoding delay and complexity in terms of providing the most good compromise. Although MPEGAAC technology than MUSICAM size in rate has a great advantage; and to provide transparency for the DAB data channel characteristics, to carry out the audio business is very easy MPEGAAC (European standard has AAC as an upgrade solution for DAB, Australia has decided to use AAC launch DAB run); but taking into account existing compatible receiver, costs, business is still one of the audio coding used MUSICAM.

3, for the audio program with the broadcast data PAD, electronic program guide EPG, traffic information TMC, rolling picture SlideShow, web publishing BWS and transparent transmission of IP datagram transmission of multimedia content such as the establishment of a mature stratified agreement, even based on different encoding formats and the way video broadcast application package provides a good foundation.

4, through the energy spread (the input with a pseudo-random binary sequence (PRBS) for model 2 plus and scramble), can be convolutional coding (bit-error-sensitive combination of features, it can be used even and non-uniform error protection (EEP 4 with uniform error protection level of protection of two sets and a non-uniform error protection UEP 5 protection level)), time interleaving and frequency interleaving, OFDM modulation (using DQPSK subcarrier modulation) to overcome the radio signals for mobile reception by the receiver and because of the Doppler effect more than to bring the signal frequency selective fading and time selective fading problem, excellent high-speed mobile reception performance (to support speeds of 200km / h).

5, bandwidth and carrier spacing in the selection of business operations by taking into account the actual capacity and demand, and the power spectral density and power consumption of the comprehensive consideration of the receiver, DAB select 1.536MHz band, there are four working models to choose from, see Table 1.

text] Beijing Radio Digital Multimedia Broadcasting Case Title Describes

By: weihua

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