Wireless TV broadcasting systems
PJSC “ROKS” develops, manufactures and installs the MW broadcasting systems intended for work in LOS mode. In systems the original technical decisions which are based on technologies MMDS (in frequencies band 2-11 GHz), MVDS (11 – 28 GHz) and LMDS (20 - 40 GHz) which are protected by Ukrainian Patents № 24643, № 54275 and № 54644 are realized. Systems possess high power efficiency and fine ecological features and can be completed on 90 % by own manufacture products. Our broadcasting systems are established and maintained in the several countries.
|Operation frequency range, GHz||10.0 - 13.5||2.0 - 7.5||20.0 - 30.0|
|Broadcasting standards||DVB-S / DVB-S2 or DVB-C||DVB-C or DVB-T||DVB-S/S2 or DVB-T|
|Modulation types||QPSK, 8PSK or QAM64||QAM16/32/64 or COFDM||QPSK, 8PSK or COFDM|
|Coverage zone with one transmitter||up to 50 km||up to 30 km||up to 5km|
|Repeater Hops without regeneration||up to 3||no more them one||none|
|Repeater Hops with reregeration||Limited by needs||Limited by needs||Limited by needs|
|Cost of the user's equipment||The least, because of application of the satellite reception complete set||A bit more expensively than the satellite complete set for reception||Expensive, because of the high cost of subscriber receiver|
|A possible way to receive||individual and collective||individual and collective||collective|
Wireles TV broadcasting system
Most of many countries territory has one-storey building and a low population density. In addition, within the country may be areas with complex terrain (eg mountains), where the wiring or economically disadvantageous or even impossible. The creating of a powerful transmitter TV centers with large coverage zones in such regions is impractical. An alternative to high-power broadcasting systems are low-power systems with relatively small coverage zone, but on the other hand, have a low cost and require low capital investments for their deployment. The first task of these systems is to provide high-quality multi-program television residents of small towns. The sources of television programming for broadcasters such systems can be large television centers, RRLs, satellite teleports, the local studio, etc.
Historically, the first such broadcasting system was MMDS (Multichannel Multipoint Distribution Service), which 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 with a bandwidth of 6 MHz - no more than 33. 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.
The transition to digital television transmission techniques opens up new possibilities for MMDS, and MVDS (MITRIS). The main advantage is increasing the number of transmitted TV programs by at least 4 times. Building on the direction of MMDS systems the company "ROKS" offers versions of the system MMDS in non-traditional frequency bands for it, for example, 5 GHz and 8 GHz, and offers to use within the system patented new design principles of transmitters and antennas systems design, as well as new principles of relaying signals in shaded areas in the service zone. Different broadcast standards: DVB-S/S2, DVB-T/T2, and DVB-C may use for digital television systems and MMDS systems. The standard choice depends on the particular system application.
For MMDS systems we recommend a proprietary architecture that allows you to use one powerful transmitter instead of few relatively low-power transmitters with the individual transmitters signals frequency division multiplexing in propagation medium possibility (the Ukrainian Patent № 54644). We also propose 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).
Wireless TV broadcasting system based on MMDS
In Ukraine, at the time were offered cost-effective system broadcasting MITRIS (Microwave Integrated TeleRadioInformation System) which is an analog of MVDS system developed in US. Its advantages as it seems to us until the end were not appreciated. And most important of them - the highest environmental performance which are determined by a very low level of radiated power per channel (less than 10mW!). At the same time a such system coverage is usually sufficient to district centers (though there are examples of systems MVDS (MITRIS), especially cellular architecture, and in large cities). This system is remarkable by the fact that it has the lowest cost of transmission equipment on one channel, the lowest capital costs of its deployment and the lowest power consumption. Due to the high environmental characteristics MVDS (MITRIS) transmitting antenna with a microwave transmitter can be installed in any available place, for example on the roof of the tallest building, without causing any inconvenience to its residents. Because the system operates in the centimeter range and occupes about 800 MHz band (11.7-12.5 GHz) an used radio channels number may be several times larger than for MMDS.
The firm "ROKS" actively involved in the development of systems MVDS (MITRIS) at all stages. Director and specialists of the company are included in groups co-patents of Ukraine, protecting most of the technical solutions implemented or that can be implemented within systems projects MVDS (MITRIS). The firm "ROKS” is also the holder of Ukrainian patents for a “MITRIS-CS " system which is a development project MITRIS digital system towards a network broadcast the cellar structure. More than 15 years of experience in this field a team of engineers have designed many devices that are required for assembly of different configuration central station MITRIS. Our ideology which we strictly adhere to has always been an integrated approach to the formation of equipment set which allows consumers to receive from us the finished product and not puzzle over the selection of individual components.
The architecture of system MVDS offered by us (MITRIS) has shown rather useful ability to repeated relaying of a group signal without its regeneration. We patent system "MITRIS-CS" (the Ukrainian Patent № 24643) which is optimum for construction of broadcast networks that haves some of base stations, connected among themselves by means of RRLs.
With our participation offers many projects both in Ukraine and in countries near and far abroad. Geography systems using equipment from brand name "ROKS", covers the such countries: Russia, Georgia, Moldova, Kyrgyzstan, CIS countries: Spain, Iran, Kuwait, Malaysia, etc.
Wireless broadcasting system based on MVDS
At the moment the firm can offer a complete equipment set needed to create the most advanced digital broadcast systems MVDS (MITRIS). This equipment is tested repeatedly in a variety of operating conditions and showed high reliability and excellent performance. Its use opens the way for the provision of services to mass audience is really a multi-channel (up to 200 TV channels) digital television. Conceived as ways to upgrade now operated by the analog broadcast systems MITRIS towards converting them into digital with minimal alteration, and to facilitate effective communication systems MMDS and MVDS with cable networks.
MVDS (MITRIS) system in its present state has considerable development potential in terms of TV broadcasting services (such as the introduction of HDTV). These works can be carried out within the framework of specific investment projects. Although its activity company "ROKS" is mainly focused on the creation of wireless broadcast systems and the construction of the wireless broadcast systems head-end the channel-forming equipment may well be used in the construction of CATV headends which in particular can use fiber optic technology, IPTV platforms, and other systems that have marked the broadcast component.
The example of BS block diagram and the radio-frequency (RF) equipment is shown in Fig. 2. The given scheme became almost classical for broadcasting systems. The broadcasting content is formed by the TV programs received from the satellite by means of a teleport, from an air a local broadcasting transfers are received, and direct from Broadcasting Company Studio signals of local television are received. By means of professional receivers all signals are led to one broadcasting standard and to one type of the interface (basically it is ASI). Then these signals are multiplexed in program multiplexes and are scrambled by system of conditional access (CAS). Received multiplexed and scrambled data streams modulate carrier on IF according to the desirable broadcasting standard (DVB-C/-T/-S/-S2). The modulated carriers are summarized forming RF group spectrum which move on the upconverter (BUC). BUC plays a transmitter role, amplifying a signal and converting its spectrum to that band of frequencies on which the broadcasting license is obtained.
PJSC РОКС for years of the activity has constructed set of the various systems working in the most different frequencies bands (from 1 GHz to 40 GHz), using some types of modulation (from analog FM to QPSK, 8PSK, QAM32/64/128) and allowing to transfer a digital TV program content to distances from 500m to 50Km. Both broadcasting BS and network every possible architectures with set of repeaters, radio relay lines (RRL) and repeaters have been realized.
The most part of the equipment for BS (70 %, behind an exception the CAS and professional receivers) is made by PJSC “ROKS” independently, and we are proud of high quality and the comprehensible price of our workings out. RF we on 100 % develop a part and we make independently, beginning from assembly complete sets of cables and finishing difficult upconverters and antennas. That equipment which we don't make independently we buy at well-known manufacturers that guarantees high reliability of all broadcasting system complexes.