scholarly journals Model of forming a spatial-temporary radio frequency portrait of subscriber terminals in satellite communication systems monitoring

2020 ◽  
Vol 100 (4) ◽  
pp. 78-86
Author(s):  
M. Baldychev ◽  
◽  
A. Bosyy ◽  
O. Galtseva ◽  

Currently, the development of satellite communications systems (SCS) is associated with the development of signals of complex structure. The popularization and distribution of software-defined radio systems (Software-defined radio, SDR) are noted, which leads to a decrease of quality of functioning of the SCS. Promising areas of countering the unauthorized use of the time-frequency resource of the KA repeater are methods aimed at determining the location of subscriber terminals (ST) and analyzing the service and semantic parts of the transmitted message. Accounting for changes of physical parameters requires the use of a large amount of heterogeneous a priori data; it is not achievable task in practice. According to the theory of mathematical statistics, the approximation is used at solving problems of sample analysis. The result of the approximation is a spatio-temporal radio-frequency portrait (STRFP) of an ST participating in the formation of a group signal. Thus, the aim of the research is to develop a model of changing the physical parameters of a radio signal and to study the possibility of approximating physical parameters in order to form a spatio-temporal radiofrequency portrait of an ST SCS.

Author(s):  
Teodor Narytnik ◽  
Vladimir Saiko

The technical aspects of the main promising projects in the segments of medium and low-orbit satellite communication systems are considered, as well as the project of the domestic low-orbit information and telecommunications system using the terahertz range, which is based on the use of satellite platforms of the micro- and nanosatellite class and the distribution of functional blocks of complex satellite payloads more high-end on multiple functionally related satellites. The proposed system of low-orbit satellite communications represents the groupings of low-orbit spacecraft (LEO-system) with the architecture of a "distributed satellite", which include the groupings of the root (leading) satellites and satellite repeaters (slaves). Root satellites are interconnected in a ring network by high-speed links between the satellites. The geometric size of the “distributed satellite” is the area around the root satellite with a radius of about 1 km. The combination of beams, which are formed by the repeater satellites, make up the service area of the LEO system. The requirements for the integrated service area of the LEO system (geographical service area) determine the requirements for the number of distributed satellites in the system as a whole. In the proposed system to reduce mutual interference between the grouping of the root (leading) satellites and repeater satellites (slaves) and, accordingly, minimizing distortions of the information signal when implementing inter-satellite communication, this line (radio channel) was created in an unlicensed frequency (e.g., in the terahertz 140 GHz) range. In addition, it additionally allows you to minimize the size of the antennas of such a broadband channel and simplify the operation of these satellite systems.


Author(s):  
А. А. Talanov ◽  
◽  
S. А. Fedotov ◽  
А. М. Stepanov ◽  
◽  
...  

Deployment of space systems based on multi-satellite constellations to provide broadband Internet access and communication services acutely raises the question of their radio frequency support including issues of electromagnetic compatibility (EMC) between competing space systems using multi-satellite constellations (StarLink, OneWeb, Kuiper, etc.), their EMC with traditional space systems (satellite communication systems that employ spacecraft in geostationary and non-geostationary orbits, space systems of other services), as well as regulatory issues of entering into service and staged deployment of space systems. The article formulates the problematic issues of radio frequency support of modern space systems taking into account the trends of satellite constellations deployment and proposes the solutions with consideration to international and national requirements in the regulation of radio frequency spectrum including the ITU requirements and the requirements of Russian State Commission for Radio Frequencies. The paper shows the ways to share the radio frequency spectrum to meet new requirements of the World Radiocommunication Conference 2019 (WRC-19).


Author(s):  
О.В. МЕНТУС ◽  
А.А. АКОПОВ

Рассматриваются варианты построения полезных нагрузок с цифровой коммутацией для спутниковой связи на примере перспективного космического аппарата «Экспресс-АМУ4». Показано, что использование цифровой коммутации в отечественных спутниках связи позволяет обеспечить гибкость оказания услуг и более успешно конкурировать с зарубежными спутниковыми системами связи. This article considers variants of digital switching payloads for satellite communications on the example of a promising spacecraft Express-AMU4. It is shown that the use of digital switching in domestic communication satellites allows providing flexibility in the provision of services and more successfully competing with foreign satellite communication systems.


Author(s):  
Islam Md Rafiqul ◽  
Md Moktarul Alam ◽  
Ali Kodhim Lwas ◽  
Sarah Yasmin Mohamad

Attenuation due to rain is an important constraint in microwave radio link design especially at frequencies above 10 GHz. It restricts the path length of radio communication systems and limits the use of higher frequencies for line-of-sight microwave links and satellite communications. In order to predict the attenuation due to rain accurately rainfall intensity is required with 1-minute integration time. Rainfall is a meteorological phenomenon with complex structure due to its variability in space, duration and occurrence frequency, particularly in tropical and equatorial regions. Since, the statistical distribution of rain attenuation is obtained from the rain rate distribution for the region considered, it should be noted that the accuracy of the rain rate measurement affects the accuracy of the attenuation estimation. This paper presents rain intensity with 1-minute integration time measured for 6 years in Malaysia, it’s distribution, comparison with other prediction models and impact on high frequency microwave links.


Author(s):  
Д.А. ТИТОВ

Приводится алгоритм расчета накопленной дозы радиационного излучения для унифицированной конструкции бортовой аппаратуры систем спутниковой связи The article presents an algorithm for calculating the accumulated radiation dose for the unified design of onboard equipment of satellite communication systems.


2013 ◽  
Vol 846-847 ◽  
pp. 651-654
Author(s):  
Ya Dan Zheng ◽  
Jian Bo Li ◽  
Yong Luo ◽  
Ming Ke Dong ◽  
Jian Jun Wu

In this paper, a hybrid HARQ scheme was proposed by combing forced retransmission and traditional HARQ together, after analyzing the characteristics of satellite channel and the problem encountered when utilizing HARQ scheme in GEO satellite communication system. The forced retransmission can make a packet be correctly decoded more quickly and shorten the waiting delay. Meanwhile, to balance the delay and throughput, the proper parameters were given for the proposed hybrid scheme. Simulation results show that the proposed scheme performs well at decreasing the waiting delay, especially when SNR is low. The conclusion can be drawn that the proposed scheme can improve the HARQ performance in GEO satellite communication systems.


Author(s):  
Volodymyr Saiko ◽  
Teodor Narytnyk ◽  
Valeriy Gladkykh ◽  
Natalia Sivkova

An innovative solution for practical implementation in a LEO system with a "distributed satellite" architecture that can be used to provide low-orbital spacecraft communications with ground stations and users of 5G / IoT satellite services is proposed. The essence of the proposed development in the system of low-orbital satellite communication with FC-architecture is that to reduce the delay in signaling to consumers and the probability of overloading the network into a prospective system of low-orbital satellite communication, which contains artificial Earth satellites, each of which functions in Earth orbit and equipped with onboard repeaters, inter-satellite communications, a network of ground-based communication and control systems for artificial satellites of the Earth, a grouping of low-orbiting space their devices (LEO-system), which includes the grouping of root (leading) satellites and satellites-repeaters (slave), around each root satellite is formed micro-grouping of satellites-repeaters, and functions of the root satellite in the selected orbital phase of the orbital -or micro-satellites that are connected to the annular network by communication lines between satellites, and - functions of satellites-repeaters - kubsat, new is the introduction of a multilevel boundary cloud system, which is a heterogeneity distributed computing cloud structure. At the same time, the boundary clouds of the multilevel system are connected by ultra-high-speed wireless terahertz radio lines and wireless optical communication systems. The technique of estimation of access time in the proposed structure of "fog computing" on the basis of the model of access in "fog computing" with the resolution of collisions of data sources implementing the survey mode is presented.


Author(s):  
Rogelio García-Dzul ◽  
Ramón Parra-Michel ◽  
Jorge Sanchez-Venegas

The software-defined radio platforms that currently exist are mainly focused on the development of software communication blocks, leaving aside the hardware development, so the need arises to have a testing platform for hardware blocks which also allows us to interact with a radio frequency stage to perform blocks tests of complete communication systems in the air such as WiFi, Bluethoot, Zig Bee among others. This article describes the design of a platform based on a Field-Programmable Gate Array (FPGA) technology and microprocessor, which allows having multiple blocks and algorithms in hardware and software and interacting between them. In the same way there is a significant number of general purpose interfaces for testing the signals, as well as having specific interfaces which allow us to interconnect with different radio frequency platforms and communication cards with the computer. This allows you to work with different radio technologies according to your needs. A use case is presented in which a Bluethoot transmitter is tested with the use of the platform.


2021 ◽  
Vol 2 ◽  
Author(s):  
Joan Palacios ◽  
Nuria González-Prelcic ◽  
Carlos Mosquera ◽  
Takayuki Shimizu ◽  
Chang-Heng Wang

5G and future cellular networks intend to incorporate low earth orbit (LEO) satellite communication systems (SatCom) to solve the coverage and availability problems that cannot be addressed by satellite-based or ground-based infrastructure alone. This integration of terrestrial and non terrestrial networks poses many technical challenges which need to be identified and addressed. To this aim, we design and simulate the downlink of a LEO SatCom compatible with 5G NR, with a special focus on the design of the beamforming codebook at the satellite side. The performance of this approach is evaluated for the link between a LEO satellite and a mobile terminal in the Ku band, assuming a realistic channel model and commercial antenna array designs, both at the satellite and the terminal. Simulation results provide insights on open research challenges related to analog codebook design and hybrid beamforming strategies, requirements of the antenna terminals to provide a given SNR, or required beam reconfiguration capabilities among others.


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