China Multimedia Mobile Broadcasting

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 28 March 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.
• The CMMB is intended for use on small screen devices (such as GPS, PDA, or 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