Satellite Communication Channels Research Articles

Model of Satellite Communication Channel Functioning under Conditions of Episodic Synchronization with Pulse Interference Flows

The article investigates the effect of pulse interference on information reception in conditions of episodic synchronization of frames of the physical level of a satellite communication channel with streams of radio pulses of unintended interference. An analytical model of the influence of pulse interference on the reception of information in a satellite communication channel under conditions of episodic synchronization of physical-level frames with pulse interference streams is proposed. Using the example of the DVB family of standards, the combined effect of noise and unintended impulse interference on the conditional error probabilities when receiving a synchro group, the service part of the header and the information part of the frame is shown. Estimates of the average number of frames of the physical level for the duration of the interval of episodic synchronization, the number of intervals of episodic synchronization and the proportion of elementary parcels in the frame exposed to interference, depending on the duration of the pulse interference, are given. It is shown that there are such relations between the duration of the interference pulse and the continuity of the sequence, in which the phenomenon of the episodic synchronization of physical-level frames with the flow of pulse interference has a significant impact on the functioning of the satellite communication channel. The dependences of the probability of erroneous reception of a frame of the physical level of a satellite communication channel on the signal-to-interference ratio at the fixed signal-to-noise ratio and on the duration of the interference pulse are obtained. It has been found that at high signal-to-noise ratios and the duration of the interference correlated with the duration of the service part of the frame, but significantly less than the duration of the frame, the probability of erroneous reception of the frame may be higher than at lower signal-to-noise ratios due to errors when receiving the service part of the frames.

Fully Reconfigurable Photonic Filter for Flexible Payloads

Reconfigurable photonic filters represent cutting-edge technology that enhances the capabilities of space payloads. These advanced devices harness the unique properties of light to deliver superior performance in signal processing, filtering, and frequency selection. They offer broad filtering capabilities, allowing for the selection of specific frequency ranges while significantly reducing Size, Weight, and Power (SWaP). In scenarios where satellite communication channels are crowded with various signals sharing the same bandwidth, reconfigurable photonic filters enable efficient spectrum management and interference mitigation, ensuring reliable signal transmission. Furthermore, reconfigurable photonic filters demonstrate their ability to adapt to the dynamic space environment, withstanding extreme temperatures, radiation exposure, and mechanical stress while maintaining stable and reliable performance. Leveraging the inherent speed of light, these filters enable high-speed signal processing operations, paving the way to various space payload applications, such as agile frequency channelization. This capability allows for the simultaneous processing and analysis of different frequency bands. In this theoretical study, we introduce a fully reconfigurable filter comprising two decoupled ring resonators, each with the same radius. Each resonator can be independently thermally tuned to achieve reconfigurability in both central frequency and bandwidth. The precise reconfiguration of both central frequency and bandwidth is achieved by using the thermo-optic effect along the whole ring resonator path. A stopband rejection of 45 dB, with a reconfigurable bandwidth and central frequency of 20 MHz and 180 MHz, respectively, has been numerically achieved, with a maximum electrical power of 11.50 mW and a reconfiguration time of 9.20 µs, by using the scattering matrix approach, where the elements have been calculated through Finite Element Method-based and Beam Propagation Method-based simulations. This performance makes the proposed device suitable as key building block of RF optical filters, useful in the next-generation telecommunication payload domain.

FEATURE SUPPLICATION AND CLASSIFICATION MARITIME UNMANNED SURFACE VESSELS IN UKRAINE NAVAL FORCES

The work examines the relevance of the issue of the comprehensive development of the class of unmanned surface vehicles for the implementation of civil and military tasks at sea. The list of tasks that can be most successfully solved using unmanned surface vehicles has been determined. The most typical and relevant tasks at sea are various monitoring activities, search operations in accident areas, support of industrial activities, compilation and refinement of models of the sea floor relief, coastline, and so on. The circle of relevant military tasks has also been outlined, namely reconnaissance, damage to the enemy, protection of coastal areas, setup of mines, mine countermeasures, delivery of personnel and cargo to designated areas, and so on. An analysis of the characteristics of existing unmanned surface vehicles of the leading countries of the world has been conducted, as well as the possibilities of their application for the performance of a wide range of civil tasks at sea and features of their use as vehicles for carrying out military missions. It has been determined that in the process of further development, the main priorities are seen as increasing autonomy, equipping unmanned surface vehicles with modular executive systems, introducing artificial intelligence for direct control of unmanned vehicles and weapons, increasing the system's survivability, improving the technical characteristics of communication channels for information and task exchange. Currently, the most relevant channel for control is considered to be the satellite communication channel, as it is distance-independent, resistant to jamming and interception, and does not require significant energy consumption. Proposals have been made regarding the distribution of unmanned surface vehicles into classes, namely small, medium, and large, which cover all existing types of unmanned surface vehicles. The main terms and definitions of unmanned surface vehicles that are using in NATO countries have also been analyzed, and the main terms and definitions in this direction have been proposed. The purpose of the article is to make proposals for the development of unmanned surface vehicles and to identify promising areas for their use in solving various tasks at sea.

Graph Neural Networks for Traffic Classification in Satellite Communication Channels: A Comparative Analysis

Graph Neural Networks for Traffic Classification in Satellite Communication Channels: A Comparative Analysis

Block-Based Kalman Channel Tracking for LEO Satellite Communication With Massive MIMO

Low Earth orbit (LEO) satellite communication (SATCOM) is one of the most promising systems to be incorporated in the future 5G and beyond wireless networks. The combination of massive multi-input multi-output (mMIMO) with LEO SATCOM can effectively enhance the communication capacity and improve the system throughput. However, the channel acquisition and tracking are challenging due to the severe Doppler shift and long propagation delay under the LEO SATCOM channel’s time-varying propagation environment. In this work, we propose a block-based (BB) Kalman channel tracking scheme for LEO SATCOM with mMIMO. Firstly the mMIMO LEO SATCOM channel model with Doppler shift and propagation delay is proposed. To reduce the tracking times in one data frame, the BB Kalman channel tracking scheme is proposed under LEO SATCOM environment. The optimal block length problem is also studied. Simulation results prove the feasibility of the proposed scheme and the block length selection criteria.

АНАЛИТИЧЕСКОЕ ИССЛЕДОВАНИЕ ВЛИЯНИЯ ИОНОСФЕРЫ НА ЭНЕРГЕТИЧЕСКИЕ СООТНОШЕНИЯ В СПУТНИКОВЫХ СИСТЕМАХ СВЯЗИ МЕТОДАМИ ФИЗИЧЕСКОЙ КИНЕТИКИ ПЛАЗМЫ

In civil aviation, an urgent and important task is to provide air traffic participants with uninterrupted radio communication. Satellite communication is a global mobile network covering the entire surface of the Earth, including polar regions, which provides a two-way data and voice communication exchange. An analysis of the principles of functioning of satellite communication systems (SCS) showed that the determination of energy characteristics is of great importance. Energy characteristics in satellite communication channels and the level of interference determine SCS operational capabilities and quality indicators. One of the critical factors that determine the effectiveness of the SCS functioning is the conditions for the propagation and absorption of radio waves, including ionospheric phenomena, which are not yet fully understood, and this determines the research relevance. This article is devoted to theoretical studies of the ionospheric plasma by the methods of physical kinetics to increase the energy potential of the radio links of a satellite communication system.

Total and Minimum Energy Efficiency Tradeoff in Robust Multigroup Multicast Satellite Communications

Satellite communication is an indispensable part of future wireless communications given its global coverage and long-distance propagation. In satellite communication systems, channel acquisition and energy consumption are two critical issues. To this end, we investigate the tradeoff between the total energy efficiency (TEE) and minimum EE (MEE) for robust multigroup multicast satellite communication systems in this paper. Specifically, under the total power constraint, we investigate the robust beamforming aimed at balancing the TEE-MEE, so as to achieve the balance between the fairness and total performance on the system EE. For this optimization problem, we first model the balancing problem as a nonconvex problem while deriving its approximate closed-form average user rate. Then, the nonconvex problem is handled by solving convex programs sequentially with the help of the semidefinite relaxation and the concave-convex procedure. In addition, depending on the solution rank value, Gaussian randomization and eigenvalue decomposition method are applied to generate the feasible solutions. Finally, simulation results illustrate that the proposed approach can effectively achieve the balance between the TEE and MEE, thus realizing a tradeoff between fairness and system EE performance. It is also indicated that the proposed robust approach outperforms the conventional baselines in terms of EE performance.

Computational approach to the structure spectral analysis of GERT-network models of mobile object monitoring systems

The paper considers the application of the computational approach to the structure spectral analysis of GERT-network models of mobile object monitoring systems. The structure of the system for monitoring mobile objects using satellite communication channels is presented, in particular, the structure of the system for monitoring the flight path of aircraft. It is shown that the structure of monitoring systems can be represented as a GERT-network model, which allows at the initial stage to consider various options for the formation of interaction between a mobile object, for example, a manned or unmanned aerial vehicle, and a ground control complex. The main idea of the approach is to transform a known graph into a graph with the desired spectrum, which corresponds to a valid implementation of the GERT network graph. Obviously, the set of admissible implementations also includes a graph with the maximum probability of completing the process in a given time. The results are presented, which allow, when analyzing the GERT-network structure of a monitoring system, to assess, by fairly simple methods, the compliance of a structure variant with a number of requirements that apply to the system as a whole.

ОБЗОР ИСТОЧНИКОВ ПОМЕХ В СПУТНИКОВЫХ СИСТЕМАХ СВЯЗИ

The article discusses some sources of interference in satellite communication channels, such as the impact of the ionosphere, space weather and the impact of man-made sources of interference. It is shown that satellite information transmission systems remain relevant and continue to develop, plans and projects for the further development of this type of communication in the Russian Federation are also considered. The relevance of VSAT systems and the scope of their current application are considered, as well as possible ways of using this type of satellite communication are proposed, the main methods of application are monitoring systems and communications in remote places of our planet, as well as the study of space and monitoring the state of satellite repeaters located in outer space. The advantages and disadvantages of building such systems are analyzed, and the idea of leveling the emerging shortcomings by using cognitive radio technologies using the capabilities of software-defined radio systems is proposed.

Diurnal variability of rain and rain-induced propagation impacts at a tropical location: A seasonal comparison

The knowledge of diurnal cycle of rainfall (DCR), is crucial for meticulous understanding of the rain climatology, and thus quite imperative for devising precise rainfall forecasting models which is important for future satellite communication channel modelling. The location of Kolkata is characterized by stratiform, convective as well as mixed type of rainfall during different seasons of the year. The rain diversity prevailing over Kolkata, located at the verge of the tropics, prompts critical investigation of rain and rain-induced impairments. The present study utilizes 4 years data of ground-based observations over Kolkata. The present study not only highlights significant features of DCR during the pre-monsoon and the monsoon days but also indicates the distinct variability of rain-induced propagation impairments associated with the rain drop size distribution pattern.

Research on Equalization Technology of Broadband Satellite Communication Channel

Satellite channel is the representative non-linear channel with limited frequency band. The random change of the channel causes the communication stability to be affected. With the development of satellite communication technology, the bandwidth of satellite communication has increased and the data rate has also increased significantly, resulting in more serious code interference, which has become a key factor affecting communication quality. Finding an efficient equalization technology to eliminate channel inter-code interference is the key to ensuring satellite broadband communications. This article first briefly discusses the principle of eliminating inter-symbol interference and common equalizer algorithms, and summarizes the main factors that affect the performance of channel equalization algorithms. On this basis, an improved LSTM blind equalization algorithm is proposed.

Stability of radio loops covering navigation systems and communication systems

The development of the concept of E-navigation in modern shipping makes it necessary to create very reliable lines for the transmission of information packets and the interchange of data via radio networks to a huge number of consumers, practically all over the world. With such a scale, radio communication must be extremely reliable and stable, which is provided by the planetary system of satellite communication channels. The study proposes a method of signal loops of satellite communication systems for diagnosing the quality of the radio path, which will allow quickly localizing the external causes of the deterioration of the linear stability of communication in the absence of deep diagnostics during the daily operation of radio transmitting equipment. The organization of an external loop will make it possible to make a more accurate spatial adjustment of the antenna system to the zone of stable traffic with an increase in the steepness of the guidance system characteristics according to its own signal returned from the loop from the satellite. The external loop allows for more precise tuning of the antenna system of the stations, relative to the “steepness” of your own signal and to localize the external causes of signal deterioration by applying the method of signal loops.

MODERN APPROACHES TO THE ORGANIZATION OF A RELIABLE JAM–RESISTANT AND SECURED SATELLITE COMMUNICATION CHANNEL WITH UNMANNED AERIAL VEHICLES

At the present stage of development of unmanned aircraft systems work continues at a rapid pace to further improve their capabilities in the direction of more effective combat and special tasks.
 This is especially noticeable in two key areas: increasing the range and flight duration; reducing the physical size of the unmanned aerial vehicles.
 The combination of increasing flight duration and decreasing design characteristics significantly affects the requirements for unmanned aircraft system communication equipment and the development of a beyond line of sight satellite communication channel, which is currently considered as the main channel for transmitting intelligence, telemetry information in real time. Under existent warfighting conditions, the development of communication lines on the principle of a beyond line of sight with the use of ground or airborne relay stations, or through the introduction of additional ground control stations is virtually unjustified, due to the high dynamics of operational conditions and time constraints for decision making.
 In this context, the unmanned aerial vehicles' satellite communication channels are subject to strict requirements to ensure the combat missions are carried out successfully and safely.
 The article examines current approaches to the implementation of satellite communication channels with unmanned aerial vehicles in the context of the requirements for both on–board equipment and directly to the development of a satellite communication channel. Recommendations are given for the basic requirements for the organization of satellite duplex communication beyond line–of–sight with unmanned aerial vehicles based on geostationary (medium-altitude) high throughput satellites in the Ka frequency range.

Research on Continuous Signal Mask Separation in Satellite Communication

With the rapid development of communication technology, satellite communication has been very popular in our life. However, due to the openness of satellite communication channel, the communication security has been a hot topic. The large signal masking technology is a potential solution to improve the safety of satellite communications in recent years. To achieve this technique, an efficient and reliable signal separation method must be supplemented at the receiver. Based on existing methods, there are problems of low accuracy of parameter estimation and complex estimation process. The improved scheme introduces the Amplitude and Phase Estimation(APES) based parameter estimation procedure, and proposes a new scheme consisting of APES algorithm, Costas loop and Least Mean Square (LMS) adaptive filter. Compared with existing methods, the simulation results show that the proposed method can achieve mask signal separation successfully, and can achieve better separation performance.

Multidimensional spatial transformation of streaming video in satellite communication channels

The problem of compression of high-resolution streaming video for transmission over low-speed satellite communication channels of small spacecraft is considered. It has been determined that the specificity of using small spacecraft in low orbits, on the one hand, imposes a number of restrictions on weight and size characteristics and energy consumption, on the other hand, it opens up new opportunities for obtaining high-resolution visual information. Approaches to real-time video data compression are considered, which make it possible to implement a subminiature encoder in the “system-onchip” basis. A coding method based on the complex principles of AV1 coding and multidimensional spatial transformation is proposed. The practical attainability of the developed method and algorithms is shown. The ways of developing the method and creating a video data compression system are proposed.

Adaptive Modulation Scheme for Satellite Communication Channel Based on RLNN

This paper discusses the potential applications of reinforcement learning in communication systems. In order to improve the spectral efficiency of wireless communication channels, we propose an adaptive modulation scheme based on reinforcement learning and deep neural network (RLNN) with a average network exploration(AE) strategy. Although the application of machine learning technology in link adaptation has attracted widespread attention, most of the solutions currently proposed are based on offline training algorithms, which are not suitable for real-time operations. Classical reinforcement learning is only effective in discrete actions and states. The proposed technical solution does not depend on the offline training mode. The proposed technical solution uses AE strategy to drive exploration, which can improve the exploration efficiency of the agent. The simulation result shows that we can increase the data transmission rate under limited bandwidth and independently improves link availability, throughput and the efficiency of the wireless communication system.

Effective Methods and Performance Analysis of a Satellite Network Security Mechanism Based on Blockchain Technology

In satellite communication systems, satellite power and processing capacities are limited, which means that storage and security are also constrained. Satellite communication channels are extremely vulnerable to hackers and external interference signals. Protecting satellite networks from illegal information access and use can be extremely challenging. In this paper, an architecture composed of satellite and ground equipment is developed that integrates communication network authentication and privacy protection structures. In the proposed scheme, the communication, registration, authentication, and revocation of information are achieved through stages to improve communication security. The satellite forwards the collected information to a ground base station, which has a strong data processing capacity. The ground base station records all the key parameters in the distributed blockchain, and all malicious node certificates are removed from the system. To further enhance data transmission security, the key is transferred using an asymmetric encryption algorithm. To measure the robustness of using the proposed network architecture, under the same attack condition, an invulnerability analysis is performed. After conducting simulation experiments, the results show that the proposed scheme greatly improves communication security and protection.

Results of radio sounding of the south polar auroral oval performed with the GNSS signals of a sledge-track train around the Russian Antarctic station "Vostok"

Under the program of the 60th Russian Antarctic expedition of the 2014-2015s, during the sledge-tracked crossing of Antarctica to Vostok station 8.01.2015-19.01.2015, an experiment was conducted to receive signals from navigation services of satellite communication channels of GLONASS/GPS systems (GNSS). The technology of radio sounding and the criteria for diagnostics of the auroral oval in the total electron content of ionosphere (TEC) are discussed. Radio sounding of the ionosphere reveals traces of auroral oval in the latitudinal distribution of ionospheric delay of GLONASS/GPS signals. Examples of manifestation of the auroral oval are given. The transition route is calculated. The obtained results are compared to the results of SIMP2 modeling of the auroral oval and to data from the official internet page of the experiment. The necessity of creating of a TEC-model of the auroral oval is shown.

Information Resources Economy in Satellite Systems based on New Microwave Polarizers with Tunable Posts

One of the fundamental problems of modern digital telecommunications is the economy of digital information and frequency resources, which are highly limited. The introduction of novel telecommunication systems and 5G networks requires searching for principal solutions for the economy and reusing the frequency spectrum. Therefore, modern wireless mobile, terrestrial, and satellite systems use various new technologies to increase communication channels' information capacity for the economy of limited frequency resources. One of the most effective ways to reuse the information system's operating frequency band is to apply antennas with polarisation signal processing. Such systems provide the possibility to transmit and to receive simultaneously signals with different types of polarisation. Consequently, the application of electromagnetic waves with two orthogonal polarisations improves wireless systems' information characteristics for various purposes. This allows doubling the information capacity of mobile, terrestrial, and satellite communication channels. Also, polarisation processing is carried out in meteorological and radar systems to receive, transmit, and process information. The essential elements of such systems are microwave polarisers and orthomode transducers. The electromagnetic characteristics of these devices affect the aspects of the whole system significantly. Main electromagnetic factors include phase, matching, and polarisation parameters. The article presents the development of a compact tunable polarizer based on a square waveguide with three posts. The developed polariser operates in the X-band from 8.0 GHz to 8.5 GHz. Created a mathematical model of the polariser is based on the scattering and transmission matrices. To verify the developed theoretical model's correctness, the calculation of all characteristics was also performed numerically using the finite integration technique. The developed compact polariser based on a square waveguide with three posts allows tuning it's matching and polarisation characteristics by changing all posts' heights. The developed polariser's main advantages are small dimensions, tuning options, and aspects of polarisation transformation.

Automated system for operational chemical and radiation monitoring of water areas of the Arctic zone of the Russian Federation with flooded underwater potentially dangerous objects

Long-term operational control systems for pollution of the aquatic environment near potentially dangerous underwater objects in ice conditions in the Arctic zone of the Russian Federation are described. The systems are based on the use of bottom stations that measure the levels of radiation and chemical pollution of the aquatic environment and transmit monitoring information via satellite and (or) sonar communication channels. The information transmitting via the satellite communication channel is carried out by the direct ascent of the station itself, and in the case of ice cover, the transmission of information is carried out using a pop-up antenna unit capable of drilling ice. Transmission via the sonar communication channel is carried out between the stations and the receiving unit.