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What is MMDS?

Date:2014/4/10 12:11:45 Hits:


Multichannel Multipoint Distribution Service, also known as MMDS or Wireless Cable, is a wireless telecommunications technology, used for general-purpose broadband networking or, more commonly, as an alternative method of cable television programming reception. MMDS is used in Canada, Mexico, Dominican Republic, Iceland, Ireland, Russia, Slovenia, Brazil, Barbados, Australia, Nigeria, Pakistan, Sri Lanka, Thailand, Uruguay, India, Belarus and Cambodia. It is most commonly used in sparsely populated rural areas, where laying cables is not economically viable, although some companies may also offer MMDS services in urban areas.


Technology
The MMDS band uses microwave frequencies from 2 GHz to 3 GHz in range. Reception of MMDS-delivered television signals is done with a special rooftop microwave antenna and a set-top box for the television receiving the signals. The antenna usually has an integrated down-converter to transmit the signals at frequencies compatible with terrestrial TV tuners down on the coax (much like on satellite dishes where the signals are converted down to frequencies more compatible with standard TV coaxial cabling), some larger antennas utilise an external down-converter. The receiver box is very similar in appearance to an ****ogue cable television receiver box.

The MMDS band is separated into eleven "channels" which are auctioned off like other bands. The idea was that entities could own several channels and multiplex several television and radio channels onto each channel using digital technology. Each "channel" was capable of 10 Mbit/s, exclusive of any forward error correction technology that is required for this type of technology.

MMDS and DOCSIS+

LMDS (Local Multipoint Distribution Service) and MMDS have adapted the DOCSIS (Data Over Cable Service Interface Specification) from the cable modem world. The version of DOCSIS modified for wireless broadband is known as DOCSIS+.

Data-transport security is accomplished under MMDS by encrypting traffic flows between the broadband wireless modem and the WMTS (Wireless Modem Termination System) located in the base station of the providers network using Triple DES.

DOCSIS+ reduces theft-of-service vulnerabilities under MMDS by requiring that the WMTS enforce encryption, and by employing an authenticated client/server key-management protocol in which the WMTS controls distribution of keying material to broadband wireless modems.

LMDS and MMDS wireless modems utilize the DOCSIS+ key-management protocol to obtain authorization and traffic encryption material from a WMTS, and to support periodic reauthorization and key refresh. The key-management protocol uses X.509 digital certificates, RSA public key encryption, and Triple DES encryption to secure key exchanges between the wireless modem and the WMTS.

MMDS provides significantly greater range than LMDS.

MMDS may be obsoleted by the newer 802.16 WiMAX standard which is due in 2004.

MMDS is sometimes expanded to Multipoint Microwave Distribution System or Multi-channel Multi-point Distribution System. All three phrases refer to the same technology.


Current Status

In the United States, WATCH Communications (based in Lima, Ohio), Eagle Vision (based in Kirksville, MO), and several other companies offer MMDS-based wireless cable television, Internet access, and IP-based telephone services.

In certain areas, BRS is being deployed for use as wireless high-speed Internet access, mostly in rural areas where other types of high-speed internet are either unavailable (such as cable or DSL) or prohibitively expensive (such as satellite internet). CommSPEED is a major vendor in the US market for BRS-based internet.

AWI Networks (formerly Sky-View Technologies) operates a number of MMDS sites delivering high-speed Internet, VoIP telephone, and Digital TV services in the Southwestern U.S. In 2010, AWI began upgrading its infrastructure to DOCSIS 3.0 hardware, along with new microwave transmission equipment, allowing higher modulation rates like 256QAM. This has enabled download speeds in excess of 100 Mbit/s, over distances up to 35 miles from the transmission site.

In the early days of MMDS, it was known as "Wireless Cable" and was used in a variety of investment scams that still surface today.[3] Frequent solicitations of Wireless Cable fraud schemes were often heard on talk radio shows like The Sonny Bloch Show in the mid-1990s.[4]

In Ireland, since 1990,[5] UPC Ireland (previously Chorus and NTL Ireland) offer MMDS TV services almost nationwide. The frequency band initially allocated was 2500–2690 MHz (the “2.6GHz band”) consisting of 22–23 8 MHz analogue channels; digital TV was restricted to 2524–2668 MHz, consisting of 18 8 MHz digital channels. Two digital TV standards are used: DVB-T/MPEG-2 in the old Chorus franchise area and DVB-C/MPEG-2 in the old NTL franchise area. The existing licences were to expire 18 April 2014 but Comreg, the Irish communications regulator, extended the licences for a further 2 years to 18 April 2016 at which date they will expire together with all associated spectrum rights of use. The 2.6 GHz band spectrum will be auctioned off so that when the existing MMDS licences expire new rights of use can issue on a service and technology neutral basis (by means of new licences). As a result, holders of the new rights of use may choose to provide any service capable of being delivered using 2.6 GHz spectrum. For instance, they could distribute television programming content, subject to complying with the relevant technical conditions and with any necessary broadcasting content authorisations, or they could adopt some other use.[6]

In Iceland, since November 2006 Vodafone Iceland runs Digital Ísland (Digital Iceland) - the broadcasting system for 365 (media corporation), (previously operated by 365 Broadcast Media). Digital Ísland offers digital MMDS television services using DVB-T technology alongside a few analogue channels. The MMDS frequency range extends from 2500–2684 MHz for a total of 23 8 MHz channels, of which 21 are considered usable for broadcasting in Iceland. Analogue MMDS broadcasting began in 1993, moving to digital in 2004.

In Brazil, MMDS technology was shut down in 2012 to release the frequency for the LTE-UTRAN band in 2500–2600 MHz. The national shutdown is planned to be finished at the end of 2012.

In the Dominican Republic, Wind Telecom started operations using MMDS technology in 2008; at that time and ever since it became a pioneer taking advantage of such implementations. The company uses the DVB standard for its digital television transmissions.

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