N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 9 - Wireless Systems and Technologies                                                                                 Slide 48 of 80                                                                                                    ________________

    What is MMDS ?

                                    Analogue Transmission

                                    Capable of Delivering Video, Data and Voice Signals

                                    Capacity - 24 TV Channels (U.S.)

                                    Used to Provide CATV Service in Areas Where Cable
                                       Laying is not Viable

                                                                                                   ________________

The Multi-channel Multi-point Distribution Service (MMDS) is a broadcasting and communications service that operates in the ultra-high-frequency portion of the radio spectrum between 2.1 and 2.7 G Hz. MMDS is also known as wireless cable. It was deployed as a substitute for conventional cable television. It also has applications in telephone, fax and data communications..

The MMDS is usually a one-way transmission limited to 24 channels. It uses terrestrial microwave transmitting stations broadcasting in G Hz. The signal transmission radius can real to 70 miles in flat terrain ( much less in hilly and mountainous areas). The two-way transmission range is about 6 miles.

This service is used to provide "Cable Television" in areas where cable-laying is too expensive or too difficult due to terrain considerations.

The MMDS frequency band has room for several dozen analogue or digital video channels along with narrowband channels. The narrow band channels were originally intended for use in educational settings.