scholarly journals Features of the Use of Phase-Manipulated Pseudo-Random Signals without On-Board Processing in Satellite Communication Systems with a Nonlinear Repeater

2021 ◽  
Vol 24 (3) ◽  
pp. 46-52
Author(s):  
A.N. Mursaev ◽  
S.V. Zinkin
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Directional Pattern ◽  
Adaptive Antenna ◽  
Communication Line ◽  
Energy Potential ◽  
Joint Application ◽  
Random Signals ◽  
Communication Lines ◽  
Antenna Systems

The features of the use of phase-manipulated pseudo-random signals without on-board processing in satellite communication systems with a nonlinear repeater are analyzed. In particular, the process of passing signals through a nonlinear repeater is considered, taking into account the resulting combinational interference. In more detail, attention is paid to one of the ways of noise protection of satellite communication lines - the use of spatial signal processing and interference in antenna systems. Depending on the type and number of subscribers served by antenna systems, the implementation of the above method is possible by using spatial selection of signals and interference, based on the use of antennas with narrow directional patterns; spatial interference rejection, based on the use of adaptive antenna systems that form dips in the directional pattern in the direction of interference sources; suppression of narrow-band interference in the notch frequency filter and the joint application of all these methods of interference suppression. The placement of multipath antennas on board a repeater satellite, in addition to increasing the noise immunity of satellite communication lines, provides: an increase in the energy potential of the satellite communication line; multiple frequency reuse; multi-station access with time separation and switching of beams on board; the formation of a given service area from a system of independent partial beams with intersecting narrow radiation patterns; the protection of satellite communication lines due to the localization of electromagnetic radiation in a narrow solid angle. The use of multipath antennas with a large number of independently controlled beams on board the repeater satellite significantly complicates the repeater and worsens its weight and size characteristics. For this reason, existing satellite communication systems use multipath antennas, which, as a rule, have no more than 7...10 beams with independent control.

scholarly journals ON THE USE OF BISTATIC UNDERWATER OPTICAL COMMUNICATION SYSTEMS

T-Comm ◽  
2020 ◽  
Vol 14 (8) ◽  
pp. 4-12
Author(s):  
Evgenia S. Abramova ◽  
◽  
Vyacheslav F. Myshkin ◽  
Valery A. Khan ◽  
Sergey F. Balandin ◽  
...  
Keyword(s):  
Laser Beam ◽  
Optical Communication ◽  
Communication Systems ◽  
Communication Line ◽  
Energy Potential ◽  
Natural Systems ◽  
Dispersed Particles ◽  
Optical Communication Systems ◽  
Receiver Unit ◽  
Communication Lines

Atmospheric and underwater optical communication lines have much in common due to variable conditions for the transmission of laser radiation along the path of the communication line, both in time and in space. The passage of a laser beam through a cloudy medium is accompanied by a decrease in the radiation intensity and an increase in the intensity of the scattered flux, which forms illumination, the intensity of which decreases with distance from the laser beam. As a rule, at the scales of distances at which the radiation of the optical range decays by several orders of magnitude, water in natural systems is homogeneous. The analysis shows that water in natural reservoirs is a light-attenuating medium both due to attenuation on dispersed particles and due to scattering on nanobubbles. The article analyzes the capabilities of atmospheric and underwater optical communication systems (POS). The results of modeling bistatic PIC in a reservoir containing particles with a diameter of 0.8 ?m and a concentration of 2 х 107 cm-3 are presented. It was shown that the parameters of the bistatic PIC pulses are significantly affected by nanobubbles in water. In natural reservoirs, the use of systems with direct line of sight is preferable. It has been shown that bistatic PICs, in which the scattering region is located on the side of the receiver unit relative to the transmitter - receiver line, have the greatest energy potential and minimal intersymbol interference. In natural reservoirs, it is possible to use such bistatic PICs for communication with a frequency of less than 20 MHz at distances of not more than 20 m. As a scattering region in bistatic PIC, you can use the bottom of the reservoir, the surface of the water or the region of water with a higher turbidity than the rest of the reservoir.

scholarly journals DEVELOPMENT OF PROPOSALS FOR SELECTING AN ENSEMBLE OF BROADBAND SIGNALS SATELLITE COMMUNICATION SYSTEMS WITH MULTI-STATION ACCESS AND CODE DIVISION OF CHANNALS

T-Comm ◽  
2021 ◽  
Vol 15 (4) ◽  
pp. 13-20
Author(s):  
Vladimir I. Filatov ◽  
◽  
Vitaly A. Julego ◽  
Valery U. Balakirev ◽  
Sergey S. Ushakov ◽  
...  
Keyword(s):  
Communication Systems ◽  
Electromagnetic Compatibility ◽  
Satellite Communication ◽  
Spatial Location ◽  
Signal Propagation ◽  
Diagnostic Methods ◽  
Power Flux ◽  
Coverage Area ◽  
Radio Monitoring ◽  
Communication Lines

When designing satellite communication lines and calculating service areas, any unfavorable combinations of signal propagation conditions are taken into account, which, during operation of the repeater, leads to a significant underestimation of the calculated signal level in comparison with the actually provided one. Under these conditions, control of the compliance of the declared characteristics with the real level of the power flux density created by the satellite repeater at the earth’s surface in order to ensure electromagnetic compatibility is the most priority task. When conducting radio monitoring of satellite communication lines using active diagnostic methods, it is necessary to rationally determine the parameters of diagnostic signals so that they meet the conflicting requirements for their confident reception after being relayed by a satellite without disrupting (reducing the capacity) of the functioning of satellite communication lines. Mathematical modeling of the retransmission path of diagnostic signals in the multi-station repeater mode, taking into account the relative spatial location of the satellite, the service area and the radio monitoring station, has been carried out. The model takes into account most of the known factors and features of the propagation of radio signals in satellite communication lines in relation to various statistical phenomena in the atmosphere (refraction, signal depolarization), as well as the instability of the position of the satellite in orbit and the associated variability of the boundaries of the coverage area. As a result of the simulation, it was concluded that under conditions of a priori uncertainty about the polarization parameters used on board the monitored satellite of the antennas, there is a fundamental possibility of active diagnostics of the repeater shafts without weakening the diagnostic signal due to polarization mismatch.

scholarly journals Methodical approach to estimation of energy characteristics of antenna arrays of space communication means of decimeter wavelengths

2021 ◽  
pp. 32-39
Author(s):  
V. V. Zvonarev ◽  
S. V. Tereschenko ◽  
M. S. Brodskiy
Keyword(s):  
Antenna Arrays ◽  
Communication Systems ◽  
Satellite Communication ◽  
Development Stage ◽  
Phased Array Antenna ◽  
Space Communications ◽  
Operating Modes ◽  
Methodical Approach ◽  
Mass Size ◽  
Antenna Systems

The article describes a sequence of mathematical and logical operations for determining the energy and mass-dimensional characteristics of an active phased array antenna operating in the decimeter wavelength range of space communications necessary to ensure continuous operation for a given time. When designing large-size antenna systems, a preliminary assessment of the mass-size, energy and thermal parameters is required to assess the feasibility of the project. In this regard, the article uses a mathematical apparatus that includes a model and methods that allow determining the tactical and technical characteristics of satellite communication systems at the design or development stage. The novelty of the developed method consists in assessing the potential capabilities of spacecraft of satellite communication and retransmission systems, taking into account the energy and weight and size characteristics of their antenna systems and in determining the degree of implementation of the main modes of operation of Earth stations at the design or development stage for the specified operating modes of satellite communication systems.

scholarly journals ANTENNAS OF MOBILE TERMINALS IN MODERN MOBILE COMMUNICATION NETWORKS (OVERVIEW)

2019 ◽  
Author(s):  
Valentin Popov ◽  
Vladimir Skudnov ◽  
Alexey Vasilyev
Keyword(s):  
Mobile Communication ◽  
Antenna Arrays ◽  
Communication Systems ◽  
Mobile Station ◽  
Line Of Sight ◽  
Adaptive Antenna ◽  
Mobile Terminals ◽  
Mobile Communication Systems ◽  
Mobile Stations ◽  
Antenna Systems

In connection with the development of technology of mobile terminals (cell phones, smartphones, tablets, computers with wireless modems, etc.) in the standards of UMTS (3G) and LTE (4G) great attention of manufacturers of these devices is concentrating on the modernization and development of antenna systems of mobile stations (terminals). Currently, antenna systems of mobile stations is implementing on base of technology in form of complex configuration microstrip transmission lines, which ensure compliance with the requirements of modern wireless communication standards. Adaptive antenna arrays and MIMO antenna systems are implemented in mobile terminals for road and railway transport, which allow to achieve a sustainable reception of signals from the base stations. As you know, the difficult conditions for the propagation of radio waves in cellular mobile communication systems are associated with their absorption, multiple reflection and scattering. In these cases, the laws that are true for the line of sight conditions (LOS, Line of Sight) no longer work. The properties of antennas integrated into mobile terminals (mobile stations - MS (Mobile Station)) directly depend on the statistical characteristics of the environment and the location of the operating terminal relative to the spatial position of the user. Therefore, when designing MS antennas in UMTS and LTE mobile communication systems in the frequency ranges from 450 to 3700 MHz, it is important to consider all of the above factors.

scholarly journals Mathematical Models of Satellite Communication Systems with Unmanned Aerial Vehicles and Counter-Means of Radio Control. Part 1

2019 ◽  
Vol 5 (3) ◽  
pp. 19-26 ◽  
Author(s):  
A. Egorov ◽  
A. Lomakin ◽  
D. Pantenkov
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Communication Systems ◽  
Satellite Communication ◽  
Radio Channel ◽  
Communication Line ◽  
Radio Communication ◽  
Target Information ◽  
Flight Duration ◽  
Aerial Vehicles ◽  
Technical Article

Currently, satellite radio communication is the main type of radio communication related to the majority of special purpose mobile objects, including unmanned aerial vehicles (UAV) of heavy and super heavy classes of long flight duration, which are forced to move over long distances up to several thousand kilometers from the take of place (airport). In this point we face the problem of quality of the channel of the satellite radio communication line on its entire way between the transmitting and receiving devices, including providing the interference protection, stealth and secrecy of transmission of command telemetry and target information. At the same time, it is necessary to take into account the possibility of using the means of radio control of a satellite radio channel from an eventual enemy, which can lead to the interception of the control channel or access to target information from the payloads of UAV. In this scientific and technical article, which consists of two parts, considered the issues of improving the efficiency of transmitted information via satellite communication channels between the UAV and the ground control and information processing point, and the issue of countering the means of radio control of the eventual enemy, formulated proposals and recommendations.

Investigation of signals with spectrum extension for protection of satellite communication lines from possible interference

2020 ◽  
Vol 4 ◽  
pp. 13-21
Author(s):  
Alexey Musaev ◽  
◽  
Sergey Zinkin ◽  
Igor Chernov
Keyword(s):  
Experimental Research ◽  
Satellite Communication ◽  
Communication Lines

The use of signals with spectrum expansion allows us to effectively solve the problems of multi-station access to a repeater for a large number of subscribers. The article presents a study of signals with spectrum extension to protect satellite communication lines from possible interference. Directions for further experimental research are recommended.

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