Radio-frequency spectrum is a valuable national and international resource. Problems of rational use of this resource are reduced to ensure electromagnetic compatibility (EMC) and are becoming increasingly important for increasing the number of radioelectronic facilities.

Different radioelectronic facilities working in one area may violate EMC conditions, it will lead to mutual interference. Interference may result from intermodulation effects, nonideal parameters of transceiver equipment and antennas, etc. OJSC Giprosvjaz helps to identify potentially interfering situations and to provide possible ways to address them.

JSV Giprosvjaz specialists use high-end specialized software, digital maps, and measuring equipment.

Radioelectronic facilities working in one area

An example of a dense placement of antennas are the masts, roofs of high-rise buildings and other tall objects on which radioelectronic facilities' antennas are installed at the same time for different purposes and working in various bands of radio spectrum: systems of cellular mobile radio standards GSM, UMTS, cdma2000, LTE, system of broadband wireless WiMAX access ( 802.16 d / e), Wi-Fi, broadcasting transmitters (both analog and digital), radio relay stations, etc.

Interference can be caused by:

• spurious emission of radioelectronic facilities' transmitters
• insufficient selectivity of radioelectronic facilities' receivers
• lack of linearity of amplitude characteristics of the transmit and receive paths of radioelectronic facilities
• formation of intermodulation products in the areas of non-linear amplitude characteristics of transmitting and receiving bars in the interaction of a variety of different signals
• electromagnetic coupling between the antenna elements of radioelectronic facilities in working frequency bands due to the nature of their structures and materials
• blocking reception path of radioelectronic facilities when the above conditions are met and in presence of a powerful transmitter

The resulting interference can degrade the quality parameters of radioelectronic facilities operation or even block the reception path.

JSV Giprosvjaz offers full study of the conditions of EMC performance, including theoretical calculations and field measurements. Theoretical studies are based on computational methods of electrodynamics, the theory of antennas and propagation, digital radio theory, the theory of radio transmitter and receiver.

JSV Giprosvjaz specialists use the information on the type and design of antennas, mast architecture and the surrounding metal structures and with the help of electrodynamics methods perform simulations of electrodynamic parameters characterizing the electromagnetic coupling between the antenna elements of different RECs, their radiation patterns and gains. Further our specialists perform calculations of total transmit power from all radioelectronic facilities located within the one area for each receiver.

Theoretical studies can be conducted at the same time with practical measurements based on advanced vector generators and spectrum analyzers.

Increased number of radioelectronic facilities

Due to the constant increase in the number of new radioelectronic facilities civil and special-purpose software on EMC conditions becomes relevant and important.

JSV Giprosvjaz performs analysis of EMC conditions during construction phase of new fixed and mobile radio networks as well as the introduction of new radioelectronic facilities.

Radio-frequency spectrum is a valuable national and international resource for determining the directions of the state policy in the field of communications. JSV Giprosvjaz performes analysis of the workload of radio-frequency spectrum as well as the conditions of the introduction of new radio technologies.

To solve EMC tasks JSV Giprosvjaz specialists use specialized software, digital maps, and measuring equipment. The software allows to perform EMC calculations, main technical parameters calculations with the help of digital maps on the basis of ITU-R Recommendations:

• Service area and interference for radioelectronic facilities group
• A group of interference effects on radioelectronic facilities
• Dueling interference situation through all possible channels of noise penetration

In cases where the criteria for noise immunity is not possible to determine theoretically OJSC Giprosvjaz specialists use specialized hardware and software complex. It can generate and measure radio signals of radio systems of the following standards: GSM, UMTS, LTE, cdma2000, Wi-Fi, WiMax, APCO, DECT, ZigBee, Bluetooth. Key feature is the possibility of simultaneous generation of a plurality of signals of different technologies.

JSV Giprosvjaz performs the following activities:

• Solving EMC problems of radioelectronic facilities
• Frequency-territorial planning for fixed and mobile radio networks
• Solving EMC problems of radioelectronic facilities located at a single site
• EMC of satellite networks
• Analytics on the use of radio-frequency resource in the world and the Republic of Belarus

EMC satellite networks

A project on implementation of national satellite communication and broadcasting networks in the geostationary orbit, which will allow Belarus to provide telecommunication services to a new level, is being developed in Belarus today. It will provide free flow of public information, the provision of private individuals and legal entities with a wide range of services (digital satellite broadcasting, data transmission, etc.), as well as the inflow of economic benefits from leasing rent satellite resources.

One of the most important issues in developing national system of satellite communication and broadcasting is a question of congestion and the use of orbital-frequency resource and its protection at the international level. OJSC Giprosvjaz specialists carried out a feasibility study on orbital-frequency resource usage. Our research activities were highly relevant for the implementation of a national satellite communication and broadcasting system.