UWDS-12M Multimedia Head-End
* An UWDS multimedia head-end operating in the frequency range of 11,7 - 12.5 GHz is intended for arrangement of digital TV
broadcasting, providing subscribers with a high-quality over-the-air Internet and IP telephony
* It was developed jointly with specialists form "Topaz" OJSC, Donetsk
* The manufacturer of these products is "Topaz" OJSC, Donetsk (tel.: 8-0622-53-13-42, fax: 8-0622-53-68-67,
Fig. 1 The base station appearance
Location of frequencies of TV and Internet signal transmission for a QAM64 modulation kind in a forward channel, for a QPSK modulation kind - in the reverse channel is specified in fig.2 (forward channel data rate is 25Mbps, reverse channel data rate is 12,8Mbps).
Fig. 2 - Location of frequencies shaped by multimedia head-end
Each digital TV channel group shaping (8...10 digital channels in each group) is effected by setting of the digital bitstreams CON-200 A/D, CON-200 D/D, CON-200 R/D of TV program signals to shapers (see fig.3). Find unit features for digital TV in the "Digital Television" section (www.betatvcom.dn.ua). The head-end comprises digital bitstream shapers: CON-200 A/D, 2 pieces; CON-100 D/D, 5 pieces; CON-200 R/D, 4 pieces, CON -200 R/D
Necessary TV program selection occurs in digital bitstream shapers of the CON-200 production line, their multiplexing and coding. Signals of subscriber control are shaped in the same shapers according to a bilingua "DVB-Manager" application (control of the subscribers using digital TV). The "DVB-Manager" application is integrated with an internet-bilingua application delivered with a DOCSIS head modem (CMTS - BSR-2000). The used software operates under a Linux OS.
The signals from CON outputs (QPSK modulation; 950-2150MHz) are summed at couplers and arrive to a the TV transmitter and the antenna 1 and 3 (see fig.2) occupying the frequency locations according to fig. 2.
An output TV and Internet amplifier (a power amplifier with a converter) provide an output power of 600mW and 200 mW respectively when intermodulation distortions of the 3d degree minus 30 dBc and minus 40 dBc. Forward and reverse channel Internet signal in a QAM modulation and QPSK modulation (DOCSIS standard; the specified modulation kind is recommended by the manufacturer for wireless applications) for the BSR-2000 output is transferred: a forward channel into 11.7-11,726GHz; signal conversion from the range of 12.470-12.500,0GHz into the range of 22-42 MHz is effected for a reverse channel operating in the frequency range of 12.470-12.500 GHz s (see fig. 2.
Fig. 3 - Master package structure chart
Multimedia notch transmitting and receiving antennas operate with a horizontal polarization (due to longitudinal slots in a sheath) while servicing a near-field region (Gain=15dB), in a far-field region antenna gain is 0dB. Polarization can be both horizontal and vertical (due to inclined transverse slots in a narrow sheath). That is why subscriber feed position is selected according to the place at the 3km distance from the base station.
A receiving antenna and a transmitting antenna at subscriber's place are implemented separately with use of two standard offset antennas (of a 0,6m diameter), one of which is for Internet forward channel and digital TV packet reception, and the other one is for Internet reverse channel transmission.
A standard satellite converter with a heterodyne oscillator frequency of 10,876GHz is used for digital TV and Internet transmission (of a forward channel) for the UWDS-12M.
TV reception subscriber set has the appearance given in fig.4 Signal from the converter output in the frequency range of 950..0.1340 MHz arrives to an SRD-200M satellite DVB-S tuner (fig.8) with the application of TV program coding using a CSA algorithm. Receiving converter power supply is effected over a drop cable and is set form the SRD-200M tuner input.
Fig. 4 - Structure chart of subscriber TV set with one antenna
Find a TV and forward Internet channel reception subscriber set structure chart and reverse Internet channel transmission structure chart in fig.5. Signal from the subscriber antenna output arrives to an SB5101E subscriber Motorola modem and an SRD-200M DVB-S satellite tuner via a power divider. The data from the SB5101E Motorola subscriber modem arrive to a switch (or a subscriber computer) and to a corporate multicomputer subscriber system (if there is any). Receiving converter power supply is effected over a drop cable and is set form the SRD-200M tuner input. Power supply of an Internet reverse channel transmitting converter is effected via the second drop cable and is set into it with the help of a PS-105F/12-1 power supply by means of a power adapter. If a subscriber needs only Internet (see fig.6), then an SRD-200M tuner is not installed. In this case power supply of the receiving and the transmitting converter is effected over both of the drop cables with the help of a PS-105F/12-1 power supply. The appearance of subscriber sets is given in fig. 7.
Fig. 5 - Structure chart of TV+Internet subscriber set with use of two antennas
Fig. 6 - Structure chart of Internet subscriber set with use of two antennas
Fig. 9 - The appearance of notch antenna and its antenna diagram in vertical plane
The coding system used in the UWDS head-ends is intended for operation not only with the subscriber receivers SRD-200M having no card bin (it increases cryptographic robustness) bit also with receivers produced by other manufacturers supplied with card bins. Currently the system is tested on Samsung (DTB 94012, DCB 9401V), Openbox (X-800) and Startrack receivers. The company sells SMART-cards to accompany the receivers and a programmer with the help of which an operator carries out a presale installation. The system is registered by a consortium DVB Project and has an ID 0x4AF7 (www.dvb.org).