Multichannel Multipoint Distribution Service (MMDS) 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). However, it also has applications in telephone/fax and data communications.
In MMDS, a medium-power transmitter is located with an omnidirectional broadcast antenna at or near the highest topographical point in the intended coverage area. The workable radius can reach up to 70 miles in flat terrain (significantly less in hilly or mountainous areas). Each subscriber is equipped with a small antenna, along with a converter that can be placed next to, or on top of, a conventional TV set. There is a monthly fee, similar to that for satellite TV service.
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.