Mobile Satellite Services Research Articles

A dual-band, beam steering and polarization reconfigurable 2-bit array antenna for satellite navigation/communication applications

A dual-band array antenna for satellite navigation/communication applications with beam steering and reconfigurable polarization functions is proposed in this paper based on four 2-bit antenna units. The 2-bit antenna unit works in the dual frequency range of 1.55–1.65 GHz (GPS L1, GLONASS L1, GSNS L1, Beidou-2 B1) and 2.0–2.2 GHz (Mobile Satellite Service, MSS, downlink), and its phase can be controlled by PIN diodes flexibly. Therefore, the proposed array antenna has dual-band and beam steering characteristics. Besides that, the polarization of the proposed array antenna can be changed by covering a metasurface and rotating it at different angles. The measured results indicate that the proposed array antenna can achieve linear polarization (LP), left-handed circular polarization (LHCP), and right-handed circular polarization (RHCP). The proposed array antenna can realize LP beam steering within 45° and CP beam steering within 30° at 1.6, 2.0, and 2.2 GHz.

Coexistence of terrestrial and non‐terrestrial networks on adjacent frequency bands

SummaryThis paper presents the latest achievements concerning 3GPP Release‐17 adjacent band coexistence simulation work on 5G new radio non‐terrestrial networks (NTNs) for satellite communications. For the first time, 3GPP considered the introduction of mobile satellite service (MSS) frequency bands for 3GPP user equipment (UE) direct connectivity with satellites and had to consider the coexistence in adjacent bands with terrestrial networks (TNs). This paper will further explain the most challenging and the main surprising outcomes of this work, which opened new market opportunities for both terrestrial and non‐terrestrial stakeholders. The main conclusions can be summarized as follows: (1) NTN UE can reuse the current requirements of the TN UE, (2) the satellite connectivity does not require a dedicated satellite waveform, and (3) TN can co‐exist with NTN on adjacent channels with relaxed ACIR requirements for the tested simulation scenario.

Requirements on Satellite Access Node and User Equipment for Non‐Terrestrial Networks in 5G New Radio of 3GPP Release‐17

SummaryFor the first time, 3GPP considered in Release‐17 the introduction of mobile satellite service (MSS) frequency bands for 3GPP user equipment (UE) direct connectivity with satellites and had to consider the coexistence in adjacent bands with terrestrial networks (TNs). This paper will further explain the most challenging and the main surprising outcomes of this work, which opened new market opportunities for both terrestrial and nonterrestrial stakeholders. 5G New Radio nonterrestrial networks (NTNs) for satellite communications are representing a major breakthrough in the history of telecommunication for the capability of reuniting two different types of services, that is, terrestrial and nonterrestrial, by reusing the same waveform and potentially the same type of terminal. One of the major conclusions of the 5G NR NTN 3GPP work in Release‐17 was that NTN UE could reuse the current requirements of the TN UE. For this reason, the same terminal can connect to both TNs and to nonterrestrial satellite constellations. Consequently, the market is not fragmented and therefore there will be a real opportunity for both terrestrial and satellite operators to increase the coverage and the quality of the service all over the world. This is one of the most important breakthroughs that 3GPP Release‐17 work was able to justify because it clearly shows that satellite connectivity using 5G NR technology is not only for dedicated satellite 5G NR UE with a higher power class. On the other hand, the 3GPP work also shows that the satellite connectivity does not require a dedicated satellite waveform, because 5G NR waveform based on CP‐OFDM (for downlink) and DFT‐s‐OFDM (for uplink) is sufficient. Another important finding is that TN can coexist with NTN on adjacent channels with relaxed ACIR requirements for the tested simulation scenarios. In fact, the satellite 5G NR requirements are lower when compared with terrestrial base station (BS) requirements from previous 3GPP releases. The satellite ecosystem tremendously changed after these findings, and both satellite and terrestrial stakeholders now see a potential market opportunity.

Authentic routine ship-shore communication in the Northern Adriatic Sea area – A corpus analysis of discourse features

In the global maritime industry, ineffective and ambiguous communication often is a main or contributing cause of shipping accidents. Nevertheless, because of the limited availability of authentic data, quantitative studies in maritime communication are rare. In addition, previous studies seem to have used the Standard Marine Communication Phrases as the prescriptive maritime communication standard, thus overlooking the superordinate role of the Manual for Use by the Maritime Mobile and Maritime Mobile-Satellite Services published by the International Telecommunication Union. Therefore, this paper uses a specialised spoken corpus of authentic routine ship-shore communication to quantify the rate of compliance of authentic routine ship-shore communication with the standard protocol of communication for ships and shore services as the key communication agents in the provision of navigational safety and efficiency. The findings show that authentic routine ship-shore communication still significantly deviates from the standard protocol of communication. In addition, the rate of compliance varies across the analysed elements and between the two communication agents examined in this study. Finally, the results indicate the need for harmonisation between the documents that define the standard protocol of communication.

An ultra‐wideband polarization insensitive frequency selective surface for shielding applications

A dual layer polarization-insensitive frequency selective surface (FSS) with ultra-wideband response for electromagnetic shielding is presented in this article. In the proposed configuration, a single layer FR4 dielectric substrate is used in which the top metallic layer comprises of combined square and circle loop and the bottom metallic layer comprises of combined swastika shape and circle loop. The proposed FSS exhibits a 13.5 GHz ultra-wide stop band response from 2.3 to 15.8 GHz. The proposed FSS has a fractional bandwidth of 148%, and the structure is polarization insensitive for the incident angles up to 450 in both TE and TM modes. The performance of the simulated structure is compared with the fabricated structure and the measured results are in tune with the simulated results. It can be used for shielding applications of Wi-Fi frequency bands 2.4 GHz, 3.6 GHz, 4.9 GHz, 5 GHz, 6 GHz, X band microwave link communication, and aircraft mobile satellite services.

Improved Ciphertext-Only Attack on GMR-1

The GEO-Mobile Radio Interface-1 (GMR-1) is a satellite communication standard used in Thuraya, a United Arab Emirates-based regional mobile satellite service provider. The specification of the encryption algorithm used in GMR-1 was not disclosed until it was uncovered by Driessen <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> in 2012 through reverse engineering. Given that A5-GMR-1, a stream cipher used in GMR-1, is primarily based on A5/2, Driessen <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> presented a ciphertext-only attack from the attacks on A5/2. Their ciphertext-only attack recovers the session key from multiple sets of 24 ciphertexts in an average of 32.1 min and requires 400 GB of pre-computed data. This study enhances Driessen <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> ’s ciphertext-only attack on A5-GMR-1 in all aspects of time, memory, and data. Our contributions are fourfold. First, we optimize the inefficient part of the previous attack. As a result, our ciphertext-only attack recovers the session key from multiple sets of 13 ciphertexts in less than 1 second and requires 400 MB of pre-computed data. Second, we propose novel memory-saving techniques. These techniques reduce the memory complexity to 216 ~ 289 MB without increasing the time and data complexity. Third, we present several time-memory-data tradeoff techniques. Using these techniques, we can present an attack that meets the desired conditions, such as memory minimization or data minimization. Furthermore, while the complexity of the previous attack is presented vaguely as “multiple sets” of 24 ciphertexts, these techniques allow us to accurately calculate the time, memory, and data complexity of the attack. Finally, we demonstrate that A5-GMR-1 can be attacked without frame numbers. To find out the frame number of each ciphertext, it is necessary to analyze and synchronize multiple channels. We present a plaintext recovery attack that does not require these processes.

A Multistate Channel Model Composed of Line-of-Sight and Semi-Line-of-Sight Propagation Environments for Millimeter-Wave Mobile Radio Systems

For outdoor millimeter-wave mobile radio systems, the main service area is expected to be in line-of-sight (LOS) and semi-line-of-sight (SLOS) environments. The modeling of propagation in a mixed LOS/SLOS environment is thus important in system design. For modeling propagation in an SLOS environment, the application of the Loo model developed for land mobile satellite service with roadside shadowing is promising because this model reflects the physical mechanism of radio propagation. However, the model is inconvenient in practice because its calculation involves numerical integration over an infinite range. In this article, we approximate the Loo distribution using three basic distributions, namely the Nakagami-Rice distribution (or Rician distribution), Nakagami-m distribution, and lognormal distribution. Based on the evaluation results, we propose the use of the Nakagami-m distribution in place of the Loo distribution. We demonstrate the conversion of Loo distribution parameters to Nakagami-m distribution parameters. Finally, we examine a multistate model that expresses environments composed of LOS, SLOS, and non-LOS conditions.

Four-element pentaband MIMO antenna for multiple wireless application including dual-band circular polarization characteristics

AbstractIn this article, a meander line-shaped pentaband (2.18–2.24, 2.38–2.46, 2.65–2.70, 3.10–3.32, 3.38–3.46 GHz) four-element multiple-input–multiple-output antenna is presented. The proposed antenna is also circularly polarized in two bands (at 2.2 and 2.4 GHz) with dual-polarization like right-handed at port 1 or 3 and left-handed at port 2 or 4, which is widely used for mobile satellite services (MSS) and Internet of Things applications. This antenna is designed and fabricated with compact size 50 × 70 × 1.6 mm3 on the FR-4 substrate with good diversity performance in pentaband. Simulated results of antenna-like return loss, isolation, and parameters-related diversity have also been tested experimentally in a controlled environment, which is within the permissible limit. The designed antenna will be appropriate for MSS, industrial scientific and medical (ISM), broadband radio services and educational broadband services, WiMAX radio location services, and amateur radio services. Meanwhile, specific absorption rate of the designed antenna has been examined in an empirical environment for the Fresnel radiating near-field applications.

Enabling LTE Services Under Interference from Mobile Satellite Service System

In order to meet the ever-increasing demand for the throughput of 5G mobile communications, more and more frequency bands are defined for the LTE system. However, some parts of the bands have been used by satellite services. When an LTE system in one country is within the footprint of a satellite service owned by another country, to prevent the interference from the satellite services, the LTE system will avoid using the overlapped frequency bands. In order to make use of the overlapped LTE bands, a Downlink Only Frame Structure (DOFS) approach is proposed in this paper. It treats the interfered band as a secondary carrier of a licensed primary carrier and employs a standard frame structure to transmit only downlink traffic on the band. The feasibility of the proposed DOFS approach is evaluated by both considering practical implementation parameters and using a popular commercial simulation tool at an interfered spot. The results reveal that, for most part of the evaluated zone, the SINR is good enough for 64QAM modulation.

Introduction to polar earth orbits (PEO) in the function of the satellite distress and safety systems (SDSS)

&lt;p align="LEFT"&gt;In this paper is described introduction of Polar Earth Orbits (PEO) in the function of the Satellite Distress and Safety Systems (SDSS) for all mobile applications. The results of a technical and economic study regarding the extension of the Inmarsat Geostationary Earth Orbit (GEO) satellite system to cover polar region are reviewed. In addition, also are examined the technical and practical aspects of providing an operational polar Mobile Satellite Service (MSS) for the provision of combined distress and safety communication solutions in conjunction with a commercial and defense communication systems for maritime, land and aeronautical applications. This study is considered several PEO satellite models and their probable costs for Search and Rescue (SAR) and determination MSS solutions. The practical usage of Low PEO constellation is realized by Cospas-Sarsat international project for SDSS.&lt;/p&gt;

Complementary Sierpinski Knopp fractal antenna for emergency management system

AbstractIn this paper, the design and analysis of a complementary Sierpinski Knopp fractal antenna are presented. It is realized by applying the Sierpinski Knopp space-filling curve on the basic square monopole antenna. The performance metrics of the antenna such as S11 (reflection coefficient), voltage standing wave ratio, radiation pattern, gain and current distribution at resonant frequencies are analyzed by using ANSYS Electronic Desktop software package. FR4 dielectric material is used as a substrate in which the radiating element of an antenna is printed. Vector network analyzer and anechoic chamber are used for measuring the fabricated antenna in order to validate the simulated data. The proposed antenna resonates at three frequencies that are 2.08, 4.93, and 6.46 GHz with a reflection coefficient of −20.5, −23.1, and −24.3 dB, respectively. The suggested antenna covers the frequency bands for mobile satellite service, Public Protection and Disaster Relief communication devoted to the emergency management system and INSAT C band applications.

On the Probability of Line-of-Sight in Urban Environments

Line-of-Sight communication will play a major role in the next generation of wireless technologies; from UAV-to-UAV networks, to land mobile satellite services, and mmWave cellular coverage. In this letter we present a model for predicting the geometric line-of-sight probability in different urban environments formulated based on stochastic geometry. The model combines simplicity of formulation with high degree of accuracy when compared to real-life geographic data. For two points in the 3D space, it takes the height of each point and the distance between them as input, also it takes 4 other simple parameters that describe the geometric properties of the underlying environment. Based on these inputs, the proposed model produces consistent analytic results aligned with ray-tracing of the geographic data.

The Interference Analysis of the Terrestrial Components of International Mobile Telecommunications to the Satellite Mobile Communication System in S-band

In accordance with the Radio Regulations, the S-band (Earth-to-Space 1980-2010 MHz, Space-to-Earth 2170-2200 MHz) is currently a shared frequency band both for the mobile service and the mobile-satellite (MSS) service. Both the terrestrial and satellite components of IMT have already been deployed or are being considered for deployment in some countries with the frequency bands 1 980-2 010 MHz and 2 170-2 200 MHz. Both the terrestrial and satellite components of IMT have already been deployed or are being considered for deployment. When Therefore, the potential interference issues between the two systems need to be studied. According to the characteristics of the terrestrial components of IMT and satellite mobile communication system, this paper analyzes the impact of the terrestrial components of IMT on satellite mobile communication system, and gives measures to eliminate interference.

Adjacent Channel Compatibility Evaluation and Interference Mitigation Technique Between Earth Station in Motion and IMT-2020

The millimeter wave band is becoming popular for mobile broadband usage such as fifth-generation (5G) mobile and mobile satellite services utilizing earth stations in motion (ESIM). According to the 2019 World Radiocommunication Conference (WRC-19), the 5G and ESIM systems will operate in adjacent frequency bands bounded by 27.5 GHz; therefore, the adjacent channel compatibility between ESIM and 5G should be verified. Both, the minimum coupling loss (MCL) and Monte-Carlo (MC) methods are applied to assess the worst and most practical interference effects, respectively, for all types of ESIM including the following: maritime ESIM (M-ESIM), land ESIM (L-ESIM), and aeronautical ESIM (A-ESIM). The distance and guard band between the two systems are indicated by the compatibility conditions. In addition to the conventional interference-to-noise ratio ( $I/N$ ), the throughput loss of a 5G system is proposed to assess the performance degradation caused by the ESIM interference. Two orthogonal frequency division multiplexing (OFDM) waveforms are proposed to suppress ESIM power leakage into an adjacent channel. A mathematical expression regarding the power spectral density (PSD) and frequency dependent rejection (FDR) is derived for these waveforms, suggesting that the interference can be alleviated. A measured single carrier waveform of a commercial ESIM equipment is used as the benchmark against the proposed OFDM waveforms. The windowed OFDM is able to reduce the guard band by 50–77%. The results obtained for various elevation angles of the ESIM antenna are determined to be applicable to various regions globally.

Enabling Edge Computing Ability in Mobile Satellite Communication Networks

Mobile Satellite Service (MSS) can provide users reliable communication abilities wherever they are on earth surface, even in a high-speed motion status, which can either be stand-alone or a complementary service to the terrestrial communication systems. In the recent past, diverse MSS applications have been emerging rapidly. Some introduce unprecedentedly heavy traffic transmission pressure, and some others require real-time response, both of which cannot be satisfied by legacy mobile satellite communication networks anymore. This paper proposes an enhanced strategy to enable edge computing ability on the existing satellite networks. More precisely, this paper re-architects a GEO satellite node to become a cloudlet which possesses a set of computation, storage and networking resources, and can accomplish a certain amount of computing jobs which are typically happened on centralised cloud centre on the ground. A test-bed containing the emulated cloudlet-enabled GEO satellite has been built on a single PC. Functional test and performance evaluation are conducted for FTP file transmission and HTTP web browsing services. Experimental results show that the enhanced edge computing ability can effectively and efficiently decrease bandwidth consumption and lower the response latency in mobile satellite networks.

5G INTEGRATED MOBILE SATELLITE SERVICE WITH HIGH ENERGY EFFICIENCY

Communication technology is moving towards its next generation network and 5G implementation. 5G provides high resource efficiency, continuity, reduced power consumption and increased resilience. This technology is integrated with mobile satellite service (MSS). This new architecture improves the commercial value proposition of the network, provide optimal performance and energy efficiency. It improvises the ubiquity, mobility, broadcast and security features of the existing communication system. It also provides an efficient broadband connectivity in moving platforms and good broadcast services. The long propagation delay of MSS is also addressed in this paper. We also the meet the increased backhaul demands thereby saving physical sites on ground.

Pregled nedavnih promjena u Svjetskom pomorskom sustavu pogibelji i sigurnosti vezanih uz pomorske pokretne satelitske usluge

Pregled nedavnih promjena u Svjetskom pomorskom sustavu pogibelji i sigurnosti vezanih uz pomorske pokretne satelitske usluge

Measuring Data Loss Resulting from Interference

This paper presents an observing methodology for calibrated measurements of radio interference levels and compares these with threshold interference limits that have been established for interference entering the bands allocated to the Radio Astronomy Service. The measurement time and bandwidth intervals for these observations may be commensurate with the time and frequency variability characteristic of the interfering signals and the threshold levels may be appropriately scaled from the values presented in ITU-R RA.769 using a 2000[Formula: see text]s reference time interval. The data loss for astronomical instruments may be measured as a percentage of occupancy in the time–frequency domain both for short and long measurement intervals. The observed time–frequency occupancy characteristics for non-geostationary satellite systems and earth stations in the mobile–satellite service may be incorporated into an effective power flux density simulation to obtain the effective data loss and sky blockage due to these services.

Enhancing Satellite Communications: Temperature-Compensated Filters and Their Application in Satellite Technology

The advent of high-throughput satellite (HTS) systems has opened up new horizons for communication satellites. What we are seeing is a paradigm shift from conventional satellite systems (like fixed, broadcasting, and mobile satellite services) using singlebeam to multibeam HTS satellites capable of delivering very high throughput (>20 times the total throughput offered by typical fixed satellites) [1], [2]. The use of multiple-spot beams in HTS satellites has two advantages: 1) it results in better antenna gain (due to narrower beams) and thus an improved link budget, and 2) it improves spectral efficiency due to a high-frequency reuse factor. This increasing demand for higher throughput and more transponders is driving key technologies in satellite communications. The temperature-compensated filter is one such technology that offers substantial reduction in size and weight along with improved RF performance and power-handling capability compared to previous generations of output filters.

Survey on Land Mobile Satellite System: Challenges and Future Research Trends

Mobile satellite systems can be characterized as a major solution since they offer mobile communication services to users in different environments and for several significant purposes. In numerous conditions, satellite systems have exclusive competences in terms of broad coverage, robustness, broadcast, and multicast capabilities. However, the implementation of Land Mobile Satellite (LMS) systems still faces some limitations regarding connectivity and stability, leading to unreliable communication. Therefore, the target of this paper is to offer a comprehensive overview of land mobile satellite systems and services from various perspectives. This includes the classification of LMS systems, the operating frequency bands, and the representative Mobile Satellite Services (MSS) systems. The research challenges and future research are further described. Such information will contribute to the understanding of satellite systems and the currently faced issues that must be addressed.