Sunday, February 12, 2012

Multichannel Multipoint Distribution Service (MMDS) & Local Multipoint Distribution Service (LMDS)


    Multichannel Multipoint Distribution Service (MMDS), also known wireless cable, is a broadcasting and communications service that operates in the ultra−high−frequency (UHF) portion of the radio spectrum between 2.1 and 2.7 GHz. MMDS is also known as wireless cable. It was conceived as a substitute for conventional cable television (TV). The MMDS wireless spectrum originally consisted of 33 analog video channels, which were 6 MHz wide. The evolution of video technology into digital capacities enables the carriers to convert these 33 analog MMDS channels into 99 digital, 10 Mbps data streams, enabling full Ethernet connectivity. Therefore, a carrier with a normal operation can have as much as 1 Gbps of capacity at a single transmitter providing adequate capacities for most applications. This capacity is also readily expandable by using a sector cell concept (see the analog cellular chapter to get a handle on sectors), which reuses the same frequency many times. The combination of super cells and sectors enable the carrier to reuse the same frequency many times by building multiple cell sites. When enough customers sign on and as their bandwidth demands grow, the growth in traffic can be handled expeditiously through a new cell or a new sector. The MMDS frequency band has room for several dozen analog or digital video channels, along with narrowband channels that can be used by subscribers to transmit signals to the network. The narrowband channels were originally intended for use in an educational setting (so-called wireless classrooms). The educational application has enjoyed some success, but conventional TV viewers prefer satellite TV services, which have more channels. Because of recent deregulation that allows cable TV companies to provide telephone and Internet services, along with the development of digital technologies that make efficient use of available bandwidth, MMDS has considerable future potential. An MMDS network can provide high-speed Internet access, telephone/fax, and TV together, without the constraints of cable connections.
     Local Multipoint Distribution Service (LMDS), is a broadband wireless point to multipoint communication system that provides reliable digital two-way voice, data and Internet services. The term "Local" indicates that the signals range limit. "Multipoint" indicates a broadcast signal from the subscribers, the term "distribution" defines the wide range of data that can be transmitted, data ranging anywhere from voice, or video to Internet and video traffic(Later on in the 3rd section, the emergence of LMDS shows why it is good at transmitting such a wide variety of data.)It provides high capacity point to multipoint data access that is less investment intensive. LMDS with its wireless delivery combined with a significant amount of spectrum allocated, promises to allow for a very high quality communication services. It transmits milliwave signals with-in small cells. As it has been tested by the US milatary and the corporate pioneers like the SpeedUs, it is undoubtedly a proven technology.
       Originally designed for wireless digital telivision transmission LMDS and MMDS (Microwave Multipoint Distribution System) were predicted to serve the wireless Subscription Television needs. MMDS is also a broadband wireless communication service which operates at lower frequencies. Usually, LMDS operates at frequencies above the 10Ghz range and MMDS at frequencies below the 10GHz range. Later on they were extended to offer other interactice services.

 The MMDS frequency band has room for several dozen analog or digital video channels, along with narrowband channels that can be used by subscribers to transmit signals to the network. The narrowband channels were originally intended for use in an educational setting (so-called wireless classrooms). The educational application has enjoyed some success, but conventional TV viewers prefer satellite TV services, which have more channels. Because of recent deregulation that allows cable TV companies to provide telephone and Internet services, along with the development of digital technologies that make efficient use of available bandwidth, MMDS has considerable future potential. An MMDS network can provide high-speed Internet access, telephone/fax, and TV together, without the constraints of cable connections.

   Local Multipoint Distribution Services (LMDS), is one solution for bringing high bandwidth services to homes and offices within the “last mile” of connectivity, an area where cable or optical fiber may not be convenient or economical. LMDS operates in 28GHz band to provide digital two-way voice, data, internet, and video services via high-speed dedicated links between high-density nodes in a network. The majority of system operators will be using Point-to-Multipoint PMP wireless design.
LMS was considered a broadband fixed service and it is a broadband wireless access technology originally designed for digital television transmission (DTV). It was conceived as a fixed wireless, point-to-multipoint technology for utilization in the last mile. LMDS commonly operates on microwave frequencies across the 26 GHz and 29 GHz bands. In the United States, frequencies from 31.0 through 31.3 GHz are also considered LMDS frequencies. Although LMDS may render any kind of communications service consistent with Commission rules, one current use is in competitive local exchange carrier (CLEC) service providing voice and data connectivity to business customers. LMDS uses a cellular infrastructure, with multiple base stations and small customer transceivers able to return communications.
 LMDS, as its name implies, is a broadband wireless technology that is used to deliver the multiple service offerings in a localized area. The services possible with LMDS include the following:
·         Voice dial−up services
·         Data
·         Internet access
·         Video
     LMDS may be the key to bringing multimedia data, supporting voice connections, the Internet, videoconferencing, interactive gaming, video streaming and other high-speed data applications to millions of customers worldwide over the air. As with other wireless networks, LMDS technology offers the advantage that it can be deployed quickly and relatively inexpensively. New market entrants who do not have an existing network like incumbent's copper wires or fibres - can rapidly build an advanced wireless network and start competing. LMDS is also attractive to incumbent operators who need to complement or expand existing networks.
     Like in other microwave applications, LMDS cell size too is limited by rain fade,Also, walls, hills and even leafy trees block, reflect and distort the signal, creating significant shadow areas for a single transmitter. Some operators may serve a cell with several transmitters to increase coverage; most prefer one transmitter per cell, sited to target as many users as possible.



Reference:
  •  http://en.wikipedia.org/wiki/Local_Multipoint_Distribution_Service
  • Broadband Telecommunications Handbook(VPN 3GW GPRS MPLS VoIP SIP).pdf
  • http://searchnetworking.techtarget.com/definition/Multichannel-Multipoint-Distribution-Service

14 comments:

  1. mmds can provide high speed intrnet and band uses microwave frequencies from 2 GHz to 3 GHz in range.

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  2. While the spotlight in the fixed wireless space recently has focused on the failures of local multipoint distribution service players Teligent and Winstar Communications, multichannel multipoint distribution service providers have kept a low profile. Steering clear of the limelight has fared well for MMDS players such as Sprint and WorldCom, which instead have been able to make sure their business plans are solid and their network buildouts are on track. n the meantime, broadband wireless equipment manufacturers such as Cisco Systems and ADC are gaining ground with non line-of-sight technology, which also is boosting the outlook for MMDS... Great great work!! =)

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  3. Wireless systems are being deployed to fulfil a number of functions. On a network level they are suitable for both access and backbone infrastructure.

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  4. since MMDS services have been around for 20 years, there is a wealth of experience--at least in respect to the one-way distribution technology.

    ReplyDelete
    Replies
    1. thanks king..
      pls do keep reading my blog...thanks

      Delete
  5. In an area where cable and optical fiber is not convenient, LMDS would be the solution because it brings high bandwith to homws and offices..THank you..

    KUDOS!!

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    Replies
    1. thanks alvin..
      pls do keep reading my blog...thanks

      Delete
  6. Although LMDS may render any kind of communications service consistent with Commission rules, one current use is in competitive local exchange carrier service providing voice and data connectivity to business customers. Thanks for the info nel. Keep it up.

    ReplyDelete
    Replies
    1. thanks matt..
      pls do keep reading my blog...thanks

      Delete
  7. MMDS and LMDS are greatly used by companies who might need high-speed transmission and where cables or optics might be a hard to install(terrain problems).....

    Thanks keep it up

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    Replies
    1. thanks raffy.
      pls do keep reading my blog...thanks

      Delete
  8. LMDS and MMDS, with digital two-way capability, give long distance carriers a relatively cheap starter into the local market, with multiple operating benefits...they will not need to co-locate DSL equipment in an operator’s central office, nor will they need to upgrade existing one-way cable plants to provide two-way functionality. LMDS and MMDS have huge chunks of under-utilized spectrum ready to go, more than enough to satisfy pent-up demand for high-speed Internet access. like raffy said its hard to install cables or optics. thanks this info sir...keep it up~!

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  9. thanks jed..
    pls do keep reading my blog...thanks

    ReplyDelete
  10. nice presentation pareng arnn and i agree that originally designed for wireless digital telivision transmission LMDS and MMDS (Microwave Multipoint Distribution System) were predicted to serve the wireless Subscription Television needs.

    ReplyDelete