China Multimedia Mobile 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 2.6 GHz frequency 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, Siano Mobile Silicon(with the SMS118x chip family, which support diversity and have superb performance).^[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 award winning hardware platform supporting both CMMB and DTMB (as well as others) standard waveforms based on their universal modulator hardware. While many other companies developed waveform specific hardware Unique broadband systems quickly cornered the Chinese market for CMMB and DTMB modulators.

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. ^ ^{a b} Interfax China (2006-10-25). "China releases mobile TV industrial standard". Press release. http://www.interfax.cn/displayarticle.asp?aid=18260&slug=MOBILE%20TV. Retrieved 2007-04-14. 
2. ^ "TiMi Technologies Co. Ltd.". Academy of Broadcasting Sciece. 2008-01-31. http://www.abs.ac.cn/en/Orgnization/Enterprises/200801/t20080131_2103.htm. Retrieved 2008-06-08. 
3. ^ ^{a b c} Mike Clendenin (2006-12-18). "China's mobile-TV spec similar to Europe's". EETimes. http://www.eetimes.com/showArticle.jhtml;?articleID=196604027. Retrieved 2007-04-14. 
4. ^ Interfax China (2007-03-28). "China releases first mobile TV chip based on CMMB standard - SARFT official". Press release. http://www.interfax.cn/displayarticle.asp?aid=22689&slug=CHINA-TELECOM-MOBILE. Retrieved 2007-04-14. 
5. ^ Cai Yan (2007-03-29). "Chip supports China's CMMB mobile TV". EETimes. http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=198700962. Retrieved 2007-04-14. 
6. ^ Rohde & Schwarz. "CMMB Information". http://www2.rohde-schwarz.com/en/technologies/broadcast_tv_radio/mobile_broadcast/cmmb/information/. Retrieved 2010-01-29. 
7. ^ Siano. "SMS1186" (PDF). http://www.siano-ms.com/pdfs/SMS1186.pdf. Retrieved 2010-01-29. 
8. ^ Rohde & Schwarz. "Test signals for the new CMMB and DVB-SH mobile TV systems" (PDF). http://www.rohde-schwarz.com/WWW/Publicat.nsf/article/N198_test-signals_CMMB_DVB-SH_e/$file/N198_test-signals_CMMB_DVB-SH_e.pdf. Retrieved 2010-01-29. 
9. ^ [1]

External links

• IEEE Spectrum Article
• http://www.cmmb.org.cn/ (Chinese)
• http://www.uniquesys.com Unique Broadband Systems
• http://www.siano-ms.com Siano Mobile Silicon
• http://www.teamcast.com TEAMCAST

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