subject: CMMB China Mobile Multimedia Broadcasting Standard brief (Figure)-CMMB, mobile multimedia, world integration - Communications Industry [print this page] CMMB China Mobile Multimedia Broadcasting Standard brief (Figure)-CMMB, mobile multimedia, world integration - Communications Industry
System architecture and its core technology STiMi presentation, emphasizing the importance of network security and gives the two models, the final status of the development described CMMB and prospected.
Keywords: CMMB STiMi digital rights management
1, Introduction 2006 10 24, the State Administration of Radio Film and Television, promulgated by China Mobile Multimedia Broadcasting System (CMMB) broadcast channel industry standard "GY/T220.1-2006 Mobile Multimedia Broadcasting Part 1: broadcast channel frame structure, channel coding and modulation ", defined by our self-developed mobile multimedia broadcasting transmission standard (the technical standards referred to STiMi, Satellite-TerrestrialInteractiveMulti-serviceInfrastructure). In the same year on November 29, SARFT issued a "Film and Television on the release" Shifting Multimedia Broadcasting Part 2: Complex with "> one radio, film and television industry standard notification" notice, notify the recommended industry standards: GY/T220 .2-2006 "Mobile Multimedia Broadcasting Part 2: Multiplexing." Currently no unified international mobile multimedia broadcasting technology standard, large-scale applications in the early stage, the timely introduction of the above criteria, China mobile multimedia broadcasting and related development of national industry and promote the role of great significance.
2, CMMB Introduction China Mobile Multimedia Broadcasting (ChinaMobileMultimediaBroadcasting, CMMB), is the first set of China's own R & D oriented Mobile , PDA, MP3, MP4, digital cameras, notebook computers, the following seven inches of the small screen, mobile portable handheld terminal system. It is broadcast via satellite and terrestrial wireless means, to achieve anytime, anywhere in the terminal to receive broadcast television programming and information services business.
2.1CMMB system architecture CMMB system is the use of high-power S-band satellite signal coverage across the country, using the ground transponders added to the contents of forwarding the same time and same frequency satellite signals, satellite signals complement cover blind spots, use of wireless mobile communication networks return path to form a single broadcast and two-way exchange with each other to combine the mobile multimedia broadcasting network. System architecture and composition shown in Figure 1.
CMMB system for China's vast territory, transmission environment is complex, dense eastern city of West sparse, user and business needs of many diverse characteristics, based on national conditions, to absorb advanced technology and sophisticated design of "one world" system . The system can be low cost, fast to implement mobile multimedia broadcasting signal coverage across the country to promote the east-west "digital divide" in the bridge.
2.2 STiMi channel transmission technology
CMMB system STiMi transmission technology used is the most advanced broadband wireless technology based on the application environment for broadcasting by more than 3 years developed a large number of research and development of a new technology, and is an advanced, practical and economy of the autonomous technology.
STiMi mobile multimedia broadcasting technology is designed for wireless channel transmission technology, independent research and development of CMMB in China in the core architecture. STiMi technology fully into account the characteristics of mobile multimedia broadcasting services for handheld devices that require high receiver sensitivity, mobility and Battery Power supply features the most advanced error correction channel coding and OFDM modulation techniques, improved anti-jamming capability and support for mobility, using time slot to reduce terminal power saving technology, improve endurance capacity of the terminal.
2.3 source standards STiMi CMMB transmission technology is the core of the CMMB system, but not all. China's CMMB standard system also includes video, audio, channel transmission, and many other parts of the agreement, which will be released in batches in the future. In the letter, and DRA source standards AVS standard working group is expected to be recognized CMMB, a CMMB video and audio standards. If the AVS, DRA have become an integral part of the CMMB will be our own intellectual property-related technical standards comprehensively. CMMB system that will use to meet the requirement of progressiveness and economic self technology to enhance the core competitiveness of our industry. AVS and DRA technology are the source video and audio compression technology optimized. AVS and DRA technology will accelerate the industrialization of the preparatory work completed, as planned well CMMB system-wide technical preparation.
3, Network Security Mobile multimedia networks are wireless networks, no matter how secure wireless network to use, unless the deployment of end to end encryption, or do not have the so-called real security communications. Wireless Network Communications technology There are many advantages, but not the safety of wireless and wired network security compare. Initially set up wireless networks in the choice of most companies in terms of availability and security, but also tend to availability, but with the economy growing, people on the communication requirements are not satisfied to smooth communication, but the pursuit of higher level of fluency secure communications.
3.1 CMMB need for network security
Mobile multimedia broadcasting network's credibility and security is one of the core concerns of the establishment of a safe and reliable mobile multimedia broadcasting network is necessary. Currently, the industry has some of the establishment of a safe and reliable mobile multimedia network, the proposed program, as the ultimate mobile multimedia broadcasting network, the credibility of the program is still DRM further study. A safe and reliable mobile multimedia broadcasting network, not only to protect the legitimate interests of content providers to ensure that viewers to the rich media content, also related to the mobile multimedia broadcasting industry, the viability of this new development. In mobile multimedia networks, there are two more representative of the DRM scheme: OMA-DRM standard, one-way conditional access or CA.
3.2 OMA-DRM Open Mobile Alliance OMA (OpenMobileAlliance) was formally established in early June 2002, its predecessor: OpenMobileArchitectureInitiativesupporters and WAPForum. Follow-up there a number of organizations joined the OMA, including WirelessVillage, MGIF, SyncMLInitiative, MWIF, MMSIOP and LIF.
OMA Organization in November 2002 released the world's first mobile DRM international norms?? OMADRM1.0EnablerRelease, how to build mobile network provides a guide to DRM system. OMADRM1.0 standard launch, Nokia, Motorola and other industry giants have been developed accordingly, and found many problems, thus OMADRM1.0 standards several meetings to discuss and revise. Industry organizations recently released OMA Digital Rights
