MMDS and LMDS

   

    MMDS or Multichannel Multipoint Distribution Service is a wireless broadband technology for internet access, that’s why it also known as a wireless cable. In 1970s they already used MMDS for the support of their television set by giving a clearer signal to the users. For the transmission of the signal they used terrestrial bases radio transmitters and for the receiver they only used an exclusive small digital receiver. The transmission that they used depends on the line of sight. Each of the channels can transfer in a rate of 27 Mbps and that is high enough to support the users. For the non license channel it can take a 99 MHz, 2.4 GHz and 5.7 to 5.8 GHz over the license channels. The frequency that they used is in a range belong to ultra high frequency which is 2.1 to 2.7 GHz. As the same for wired connection cable used for TV, MMDS can act the same functions. The only thing to do for MMDS to be efficient like wired cable is to boost the power that they have so that it can produce a clear signal.

     MMDS has a limited frequency spectrum. The number of channels available in RF bands characterize MMDS network. It can allocate only 200 MHz frequency spectrum, it can reduce the number of channels in the system for TV signal using 6 MHz of bandwidth, 33 channels can be fit into the spectrum. 

     The MMDS works for giving a clear signal to the users and it can accommodate many subscribers. The signal that they are using has many sources like cable head ends. Satellite, terrestrial, and cable delivered programs comprises the material to be delivered over MMDS. All satellite delivered in baseband format are remodulated and subsequently up converted to microwave frequencies. The signal that has been deliver is always passes through a heterodyne processor prior to improve MMDS frequencies. The transmission of using the antenna has arranged of about 35 miles depending on the broadcast power. Operating power is about 1 to 100 watt range. But it is a line of sight service, even if it can take too much power still it can’t support the client were living around the mountain.

     LMDS or Local Multipoint Distribution Service use to support the demands of the people for high speed broadband communication. They support them especially if they are far from the main source of signal. LMDS is also wireless technology that is used to deliver the multiple service offered in some local areas. Example services of LMDS are, voice dial up services, data, internet access, and video. LMDS operate in a higher frequency; the radio signal is limited to 5 miles of point to point service. This makes somewhat like a cellular operation in the way the carrier layout their operation.

     Benefits of using LMDS are the one reason why many local providers use this. First benefit of this is that it is very cost effective and the subscribers can easily afford it. The investors now are not afraid to invest their money upon using this system. The implementation for LMDS is also faster and not takes too much time, this is also a good factor of dealing with this system. As we all know, every one of us needs faster and reliable broadband communications. That’s why this system can help us to achieve our desire.

Reference: Broadband Telecommunication Handbook: 2^nd edition by Regis Bates