ON-BOARD DIGITAL SWITCHING OPTIONS FOR CIVIL COMMUNICATION SATELLITES

2020 ◽  
Author(s):  
О.В. МЕНТУС ◽  
А.А. АКОПОВ
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Satellite Communications ◽  
Provision Of Services ◽  
Digital Switching ◽  
Switching Options

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.

INNOVATIVE METHOD OF SATELLITE COMMUNICATION

2019 ◽  
Author(s):  
Teodor Narytnik ◽  
Vladimir Saiko
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Satellite Communication ◽  
Radio Channel ◽  
Satellite Communications ◽  
Service Area ◽  
Satellite Systems ◽  
Orbit Satellite ◽  
Geometric Size ◽  
Distributed Satellite

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.

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 ◽  
Keyword(s):  
Radio Frequency ◽  
Software Defined Radio ◽  
Communication Systems ◽  
Satellite Communication ◽  
A Priori ◽  
Complex Structure ◽  
Satellite Communications ◽  
Physical Parameters ◽  
Time Frequency ◽  
Spatio Temporal

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.

Forced-Retransmission Based Hybrid HARQ Scheme for GEO Satellite Communications

2013 ◽  
Vol 846-847 ◽  
pp. 651-654
Author(s):  
Ya Dan Zheng ◽  
Jian Bo Li ◽  
Yong Luo ◽  
Ming Ke Dong ◽  
Jian Jun Wu
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Satellite Communication ◽  
Satellite Communications ◽  
Hybrid Scheme ◽  
Satellite Communication System ◽  
Geo Satellite ◽  
Simulation Results

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.

scholarly journals INNOVATIVE SOLUTION FOR LEO-SYSTEM WITH DISTRIBUTED SATELLITE ARCHITECTURE

2020 ◽  
pp. 77-83
Author(s):  
Volodymyr Saiko ◽  
Teodor Narytnyk ◽  
Valeriy Gladkykh ◽  
Natalia Sivkova
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Satellite Communication ◽  
Fog Computing ◽  
Satellite Communications ◽  
Access Time ◽  
Artificial Satellites ◽  
Practical Implementation ◽  
Innovative Solution ◽  
Distributed Satellite

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.

scholarly journals A Hybrid Beamforming Design for Massive MIMO LEO Satellite Communications

2021 ◽  
Vol 2 ◽  
Author(s):  
Joan Palacios ◽  
Nuria González-Prelcic ◽  
Carlos Mosquera ◽  
Takayuki Shimizu ◽  
Chang-Heng Wang
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Channel Model ◽  
Satellite Communications ◽  
Mobile Terminal ◽  
Low Earth Orbit ◽  
Special Focus ◽  
Codebook Design ◽  
Hybrid Beamforming ◽  
Leo Satellite

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.

scholarly journals Dynamic Radio Links Selection for Mobile Satellite Communication Systems

2019 ◽  
Vol 5 (4) ◽  
pp. 28-36 ◽  
Author(s):  
S. Dvornikov ◽  
S. Yakushenko ◽  
D. Lyanguzov
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Satellite Communications ◽  
Radio Lines ◽  
Practical Application ◽  
Dynamic Identification ◽  
Communications Systems ◽  
Selection For ◽  
Mobile Satellite ◽  
Mobile Satellite Communication

In this paper presents suggestions for the noise immunity improval of mobile satellite communications lines in difficult physical and geographical conditions through the use of automatic dynamic identification algorithms for the suitability of radio lines and the dynamic antenna orientation devices of mobile satellite communications systems. Based on the results obtained, recommendations for practical application are formulated.

scholarly journals Precoding With Received-Interference Power Control for Multibeam Satellite Communication Systems

2021 ◽  
Vol 2 ◽  
Author(s):  
Eva Lagunas ◽  
Ana Pérez-Neira ◽  
Marc Martínez ◽  
Miguel Angel Lagunas ◽  
Miguel Angel Vázquez ◽  
...  
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Satellite Communications ◽  
Low Complexity ◽  
Limiting Factors ◽  
Practical Implementation ◽  
Interference Power ◽  
User Scheduling ◽  
Zero Forcing ◽  
The Matrix

Zero-Forcing (ZF) and Regularized Zero-Forcing (RZF) precoding are low-complexity sub-optimal solutions widely accepted in the satellite communications community to mitigate the resulting co-channel interference caused by aggressive frequency reuse. However, both are sensitive to the conditioning of the channel matrix, which can greatly reduce the achievable gains. This paper brings the attention to the benefits of a design that allows some residual received interference power at the co-channel users. The motivation behind this approach is to relax the dependence on the matrix inversion procedure involved in conventional precoding schemes. In particular, the proposed scheme aims to be less sensitive to the user scheduling, which is one of the key limiting factors for the practical implementation of precoding. Furthermore, the proposed technique can also cope with more users than satellite beams. In fact, the proposed precoder can be tuned to control the interference towards the co-channel beams, which is a desirable feature that is not met by the existing RZF solutions. The design is formulated as a non-convex optimization and we study various algorithms in order to obtain a practical solution. Supporting results based on numerical simulations show that the proposed precoding implementations are able to outperform the conventional ZF and RZF schemes.

scholarly journals A Compact C-Band Bandpass Filter with an Adjustable Dual-Band Suitable for Satellite Communication Systems

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1088 ◽  
Author(s):  
Ali Lalbakhsh ◽  
Amirhossein Ghaderi ◽  
Wahab Mohyuddin ◽  
Roy B. V. B. Simorangkir ◽  
Nima Bayat-Makou ◽  
...  
Keyword(s):  
Mobile Communications ◽  
Communication Systems ◽  
Satellite Communication ◽  
Bandpass Filter ◽  
Satellite Communications ◽  
Dual Band ◽  
Coupling System ◽  
Efficient Coupling ◽  
Quality Response ◽  
Insertion Losses

A narrowband dual-band bandpass filter (BPF) with independently tunable passbands is presented through a systematic design approach. A size-efficient coupling system is proposed with the capability of being integrated with additional resonators without increasing the size of the circuit. Two flag-shaped resonators along with two stepped-impedance resonators are integrated with the coupling system to firstly enhance the quality response of the filter, and secondly to add an independent adjustability feature to the filter. The dual passband of the filter is centered at 4.42 GHz and 7.2 GHz, respectively, with narrow passbands of 2.12% and 1.15%. The lower and upper passbands can be swept independently over 600 MHz and 1000 MHz by changing only one parameter of the filter without any destructive effects on the frequency response. According to United States frequency allocations, the first passband is convenient for mobile communications and the second passband can be used for satellite communications. The filter has very good in- and out-of-band performance with very small passband insertion losses of 0.5 dB and 0.86 dB as well as a relatively strong stopband attenuation of 30 dB and 25 dB, respectively, for the case of lower and upper bands. To verify the proposed approach, a prototype of the filter is fabricated and measured showing a good agreement between numerically calculated and measured results.

System Modeling and Precoding Design for Multi-beam Dual-polarized Satellite MIMO System

2019 ◽  
Vol 13 (4) ◽  
pp. 374-381
Author(s):  
Tao Kai ◽  
Sun Xiaoyun ◽  
Wang Yang ◽  
Jingchun Li
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Channel Model ◽  
Transmission Rate ◽  
Mimo System ◽  
System Modeling ◽  
Satellite Communications ◽  
Satellite System ◽  
System Capacity ◽  
Dual Polarized

Background: As the multimedia service develops and the transmission rate in terrestrial communication systems increases rapidly, satellite communication needs to improve the transmission rate and throughput. Multiple Input Multiple Output (MIMO) techniques can increase the system capacity significantly by introducing the space dimension, as the system bandwidth remains the same. Therefore, utilization of MIMO for satellite communications to increase the capacity is an important research topic. So MIMO techniques for multibeam satellite communications are researched in the dissertation. Objective: The goal of this work is improving the capacity of the satellite system. Multi-beam and dual-polarized technologies are applied to a satellite system to improve the capacity further. Methods: In this paper, we first introduce a multi-beam dual-polarized satellite multi-put and multiout (MBDP-S-MIMO) system which combines the full frequency multiplexing and dual-polarization technologies. Then the system model and channel model are first constructed. At last, to improve the capacity further, BD and BD-ZF precoding algorithms are applied to MBDP-S-MIMO and their performance is verified by simulation. Results: Simulation results show the performance of the BD precoding algorithm gets better with the growth of the XPD at the receiver and is almost not affected by the growth of the channel polarization correlation coefficient. In addition, with the growth of the users’ speed, the performance becomes worse. Conclusion: The multi-beam dual-polarized satellite MIMO system has high capacity, and it has certain application prospects for satellite communication.

scholarly journals Waveguide Slot Feed Section for Antennas with Circular Polarization

2021 ◽  
Author(s):  
Stepan Piltyay
Keyword(s):  
Circular Polarization ◽  
Communication Systems ◽  
Satellite Communication ◽  
Multipath Propagation ◽  
Horn Antenna ◽  
Satellite Communications ◽  
Low Noise ◽  
Operating Frequency ◽  
Circularly Polarized ◽  
Waveguide Slot

Modern information systems use circularly polarized signals. Among them are tracking systems, remote sensing systems, satellite television systems. The use of circularly polarized signals in satellite communication systems allows to combat multipath propagation of signals in the environment, which reduces interference. By reflecting signals from different objects, they transform their polarization. This makes it possible to reduce signal distortions in the receiving device, which increases the information capacity of wireless data transmission channels. In satellite communications, multi-band horn antennas are widely used. The use of such devices allows transmission of signals with high power and reception of signals with low noise level. Such systems are used as powering a reflector antenna with a wide bandwidth. For such applications, a horn antenna device has been proposed in which signals can be excited that produce left-hand circularly polarized signals and right-hand circularly polarized signals. The proposed horn antenna was powered through a slot that was cut in a rectangular waveguide. Due to the 45º angle of the slot, the antenna can generate signals with double circular polarization. The proposed design can be used without polarizing devices, which must be developed separately. The developed design of the horn antenna at the operating frequency of 16 GHz provides a peak antenna gain of 24 dB for signals with right circular polarization and a peak value of a gain of 18 dB for signals with left circular polarization. The polarization isolation is greater than 12 dB. Moreover, at the operating frequency, the maximum value of the reflection coefficient takes on a value of –17 dB. Thus, the developed waveguide slot feed section for antennas with circular polarization provide rather good characteristics in a narrow frequency band.

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