MMDS (Multichannel Multipoint Distribution Service) is traditionally referred to as "cable TV with no cable". MMDS system has a limited number of channels, which involves the use of relatively low frequency range of 2.5 -2.7 GHz and occupies frequency bandwidth of only 200 MHz. The maximum number of TV channels within bandwidth of 6 MHz depends on channels bitrate and can reach 20+. Video signal, transmitted in such a system, is similar to traditional broadcasting systems in the VHF and UHF bands which has the amplitude modulated by video signal carrier. For this reason, analog MMDS systems require relatively high-power linear transmitters. In the transition to digital broadcasting the existence of such linear transmitter is very useful because in digital MMDS signals are used standards DVB-T and DVB-C which also require a linear mode of transmitter operation. DTV coming greatly improved the abilities of MMDS - now it is possible to transmit more than 100 DTV channels in 200 MHz range.
|Parameter||MMDS (S-band, C-band)|
|Operation frequency range, GHz||2.0 - 7.5|
|Broadcasting standards||DVB-C or DVB-T|
|Modulation types||QAM16/32/64/256 or COFDM|
|Coverage zone with one transmitter||up to 30 km|
|Repeater Hops without regeneration||up to 2|
|Repeater Hops with reregeration||unlimited|
|Cost of user's equipment||A bit more expensively than the satellite complete set for reception|
|A possible way to receive||individual and collective|
For MMDS systems we recommend a proprietary architecture that allows you to use few relatively low-power transmitters with the individual transmitters signals frequency division multiplexing instead of one powerful transmitter in propagation medium possibility (the Ukrainian Patent № 54644). We also offer a new system architecture that allows you to eliminate areas of shading, resulting in transmitting signals to the multi-carrier TV system MMDS. The proposed co-channel repeaters are more efficient than traditional Gap Fillers (the Ukrainian Patent № 54275).