Radio relay stations
PJSC “ROKS” develops, manufactures, and installs direct visibility RRL equipment which work in the most different parts of MW range. We offer RRS two types: “ROS-2H-TV” and “ROKS–DTV”. Their main appointment is digital television signalling, in particular, - one multiplex of TV programs (“ROS-2H-TV”) in one trunk and several multiplexes of TV programs (“ROKS - DTV”) simultaneously in several trunks. On base “ROKS - DTV” construction multispan simplex RRL for transfer group multifrequency RF signals from head MVDDS station to remote transmitters without a digital signal regeneration but at the expense of relaying on IF is possible.
The company "ROKS" offers a family of digital radio relay stations (DRRS) on which the radio relay lines of various shapes and lengths can be built. First of all, this is portable duplex radio-relay station "ROS-2H-TV" operating in such frequency bands:
1.7…2.1 GHz – “ROS-2H-TV” – 1.7,
1.9…2.3 GHz – “ROS-2H-TV” – 1.9,
3.8…4.2 GHz – “ROS-2H-TV” - 4,
7.725…8.275 GHz – “ROS-2H-TV” - 8,
10.7…11.7 GHz – “ROS-2H-TV” - 11,
11.7…12.5 GHz – “ROS-2H-TV” - 12,
12.75…13.25 GHz – “ROS-2H-TV” - 13,
14.4…15.35 GHz – “ROS-2H-TV” - 15.
Systems in a frequency band 1.7 … 4.2 GHz can be used for operative supplying of information transmission (the reporting from places of events: concert halls, boardrooms, venues of sports and mass actions, and also in video observation systems) on mobile television station or is direct in studio which than 10 Km from a place of event within line of sight.
Systems in a frequency band 7 … 15 GHz are intended for organization of one- and multi-span radio relay lines on the general using networks. The digital information is transferred with rates 2.048 Mbps, 8.448 Mbps, 34.368 Mbps by transfer of synchronous digital streams and with transport streams MPEG-2 rates that equal multiple 6,222Mbps at digital TV signaling.
QPSK, QAM-16, QAM-64 modulations are used in DRRS.
The system classes of radiation at digital bit stream transmission rate:
- 2.048 Mbps - 1M5ОG7EBT;
- 8.448 Mbps - 7MООG7EBT;
- 34.368 Mbps - 28MОG7EBT.
In a frequency band 7 … 15 GHz depending on system execution the range of action on one span of a radio relay line is equal from 25 Km to 40 Km within line-of-sight conditions.
On the basis of receaving-transmitting digital radio relay stations "ROS-2H-TV" it is possible to build radio relay lines of a various configuration:
- radio relay lines with a simple radio trunk on one stage consisting of two terminal stations and the elementary control systems;
- radio relay lines with a compound radio trunk on a few stages, consisting of two terminal stations with a difficult control system providing allocation of digital streams at intermediate and terminal stations;
- radio relay lines without reservation (1+0);
- radio relay lines with reservation (1+1).
PJSC "ROKS" offers two basic types of RRS:
1. "ROS-2H-TV" is a RRS family developed in several bands with frequency plans lying in the frequency range from 2 to 15 GHz. They are mainly designed to transmit a television programs multiplex or E1/E3 plesiochronous hierarchy signals. ODU and IDU are interconnected by coaxial cables to transfer signals on the standard intermediate frequencies 70 and 140 MHz. Types of modulation used - QPSK, 16QAM, 32QAM and 64QAM. For television signals receiving are using set top boxes standards DVB-S and DVB-C.
2. «ROKS-DTV» is a RRS family intended primarily for transmission of multi-frequency group signals consisting of several carriers, modulated by the multiplexes of digital TV programs. Therefore, the connection to the ODU and IDU is also made with coaxial cables but in the L -range. On the air data signals occupy the few frequency trunks arranged according to the RRL frequency plan in the frequency range from 10 to 20 GHz.
Alternative to wirelines and FOL (Fiber Optic Link)
Radio relay lines can be considered as alternative to wire communication lines. They can replace wire communication practically in all cases, and fibre-optical – in very many cases. Application of DRRS in those places where lining FOL is impossible, for example in the conditions of dense city building or, on the contrary, at considerable remoteness from communication highways becomes wery actual.
What possible variants of applications for the radio relay lines constructed from DRRS manufactured by ROKS? First of all it is the main communication lines duplicating fibre-optical lines. The following scope – the cellular communication companies. For communication between base stations it is easy to use radio relay communication lines, moreover that it is possible to use the general system of power supplies for base stations and DRRS and the general mast for placing of their high-frequency equipment.
One more possibility for use DRRS – communication between divisions of the large enterprises. In this case is used the radio relay equipment which transmits a signal of format Ethernet 10 BaseT or Ethernet 100 BaseT. The Terminal station directly joins in a local network.
Communication with remote areas using RRS.
It is necessary to note such possibility of radio relay lines application as the communication in remote areas. There are a many settlementsand villages where laying of fibre-optical communication lines is inexpedient because of low requirement for a telecommunication service. But as communication there is necessary, application of low volume DRRS becomes the decision. Our firm makes complete sets of the digital radio relay stations working on rather low frequencies which don't demand high accuracy of an antennas adjustment, and their Yagi antennas easily dismounting for transportation and take not enough place. Thus range of transmission at such stations exceeds 100 Km that make it possible to use them in mobile groups for the organization of temporary communication, for example, for geologists. Especially important there is an application of such equipment for the communication in areas of natural disaster when other communication networks are destroyed. Certainly, there is still a satellite communication, but its cost till now very high.
Signaling of cable TV (QAM64)
Networks of a cable television the increasing extend now. The station for reception channels of a television broadcasting from various satellites (teleport) and their transfer on a cable network to consumers in apartments or in their house is organized. As paid channels to become more and more the organization of several reception stations in different disctricts of the city becomes very costly. Therefore, for decrease in expenses on operation the companies use cable television signaling between disctricts of the city on fibre-optical communication lines. However in many cases application of the radio relay equipment transmitting signal SDH-1 will be more budgetary variant, the volume of which one trunk has enough for transmission of 16-21 channels of television of broadcasting quality. At use of four trunks the possible quantity of transmitted television channels grows to 84.
One of variants of application DRRS has appeared last years and is connected with the group of the people having considerable means. Many of such people don't want to live in cities, and prefer to build to itself houses on the nature – in wood, near lakes. To organize communication with such separate houses, it is possible also by means of radio relay communication lines. Thus in a digital communication channel it is possible to organize telephone channels, the Internet, and means of the organization of communication with a local network of firms and the enterprises. Thus there is no necessity to dig a trench for a lining of cable lines, spoiling thus the nature around, and the house can be in a place where other communication networks nearby simply aren't present.
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