Multipoint Distributive Systems
Multichannel Multipoint Distributive System (MMDS)

A MMDS (Multichannel Multipoint Distribution Service), also known as BRS (Broadband Radio Service) or somewhere called as Wireless Cable, is a wireless telecommunications technology primarily used for broadband networking or, more commonly, as an alternative method for reception of cable television programs.

The MMDS systems use microwave frequencies at 2.1 GHz and frequencies from 2.5 GHz up to 2.7 GHz. Receiving of television programs respectively data signals delivered by MMDS is done with a rooftop microwave antenna. The antenna itself is attached to a transceiver, which makes possible receiving and transmitting of the microwave signal and converting them into frequencies compatible with standard TV tuners (much like on satellite antennas where the signals are converted down to frequencies more compatible with standard of cable TV). Some antennas can use an integrated transceiver. Digital TV channels can be then decoded with a standard cable set-top box or directly for TVs with integrated digital tuners. Common data signals can be received by the help of cable modem, supporting a DOCSIS (Data Over Cable Service Interface Specification) standard, connected to the same antenna and the transceiver.

The frequency band of MMDS systems is separated into 34 MHz channels, which were auctioned off like frequency bands for other distribution systems. The basic concept is primarily focused on how to allow transmissions with high capacity for providers through several huge distribution channels and how to multiplex them into several television and radio programs, and later general data onto each channel using digital technology. Similarly like with digital cable channels, each channel is capable to transfer up to 30 Mbit/s with 64-QAM modulation, respectively 42 Mbps with 256-QAM modulation. Due to FEC (Forward Error Correction) and other overhead, the real throughput is roughly 27 Mbps for 64-QAM and 38 Mbps for 256-QAM.

The newest MMDS band plans to prepare changes to channel size and to licensing in order to accommodate new WIMAX TDD on fixed and mobile equipments.

The LMDS and MMDS systems have adapted the DOCSIS from the specifications of cable modems. The version of DOCSIS was modified for wireless broadband as DOCSIS+.

Robustness of data transport 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 provider's network using Triple DES (Triple Data Encryption Standard).

The MMDS systems provide significantly greater range than LMDS systems. The MMDS systems may become obsolete because of the newer 802.16 WiMAX standard approved since 2004. The MMDS systems were sometimes expanded to Multipoint Microwave Distribution System or Multichannel Multipoint Distribution System. All three phrases refer to in the principle to the same technology.