China Multimedia Mobile Broadcasting
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China Mobile Multimedia Broadcasting (CMMB) is a mobile television and multimedia standard developed and specified in China by the State Administration of Radio, Film, and Television (SARFT).[1] It is based on the Satellite and Terrestrial Interactive Multiservice Infrastructure (STiMi), developed by TiMiTech, a company formed by the Chinese Academy of Broadcasting Science.[2][3] Announced in October 2006,[1] it has been described as being similar to Europe's DVB-SH standard for digital video broadcast from both satellites and terrestrial repeaters to handheld devices.[3]
It specifies usage of the S-band/U-band and occupies 25 MHz bandwidth within which it provides 25 video and 30 radio channels with some additional data channels.[3] Multiple companies have chips that support CMMB standard - Innofidei who was the first with a solution March 28, 2007,[4][5]
Other manufacturers, such as Unique Broadband Systems, were quick to enter the race and grab a share of the handheld broadcasting market with their hardware platform supporting both CMMB and DTMB (as well as others) standard waveforms.
RF Details
CMMB uses frequencies in the range 2635 - 2660 MHz (S-band) for satellite and "gap-filler" terrestrial broadcast, with additional terrestrial broadcast in the UHF band 470 – 862 MHz.[6][7] The channel bandwidth can be either 2 or 8 MHz, depending on data rate.[8]
Coverage
China Satellite Mobile Broadcasting Corporation (CSMBC), as of 2 June 2010, had completed CMMB network coverage in 317 prefecture-level cities.[9]
Versus DTMB
- The CMMB is not a Chinese national standard(GB), but the DTMB is GB 20600-2006.
- The CMMB uses QCIF or QVGA, so can not broadcast the HDTV(1080i/1080p), but the DTMB can do.
- The CMMB is intended for use on small screen devices (such as GPS,PDA,smartphone...) in a mobile scenario, while DTMB is intended for use on large screen devices (such as PC, LCD TV, PDP TV...) in a fixed scenario.
See also
- DTMB
- Digital Multimedia Broadcasting
- DVB (Digital Video Broadcasting)
- DVB-T (Digital Video Broadcasting - Terrestrial)
- DVB-H (Digital Video Broadcasting - Handheld)
- International standard
References
- 1 2 "China releases mobile TV industrial standard" (Press release). Interfax China. 2006-10-25. Retrieved 2007-04-14.
- ↑ "TiMi Technologies Co. Ltd.". Academy of Broadcasting Science. 2008-01-31. Retrieved 2008-06-08.
- 1 2 3 Mike Clendenin (2006-12-18). "China's mobile-TV spec similar to Europe's". EETimes. Retrieved 2007-04-14.
- ↑ "China releases first mobile TV chip based on CMMB standard - SARFT official" (Press release). Interfax China. 2007-03-28. Retrieved 2007-04-14.
- ↑ Cai Yan (2007-03-29). "Chip supports China's CMMB mobile TV". EETimes. Retrieved 2007-04-14.
- ↑ Rohde & Schwarz. "CMMB Information". Retrieved 2010-01-29.
- ↑ Siano. "SMS1186" (PDF). Retrieved 2010-01-29.
- ↑ Rohde & Schwarz. "Test signals for the new CMMB and DVB-SH mobile TV systems" (PDF). Retrieved 2010-01-29.
- ↑
External links
- IEEE Spectrum Article
- http://www.cbc.cn (Chinese)
- http://www.uniquesys.com Unique Broadband Systems
- http://www.siano-ms.com Siano Mobile Silicon
- http://www.teamcast.com TEAMCAST
- http://www.elettronika.it ELETTRONIKA
