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With advances in technology and growing user needs, satellite communication is changing over time. Efficiently managing resources across diverse satellite coverage areas can be significantly enhanced through the application of Artificial Intelligence (AI) and Machine Learning (ML). The intended project seeks to employ fundamental machine learning algorithms, including Weighted k-means and Gaussian Mixture Model (GMM), to cluster user demands within a designated geographical region. This approach aims to optimize the utilization of satellite bandwidth in a multi-beam satellite system. A comparison of the results obtained using two techniques indicates improved performance of the GMM in terms of allocating the user demands. To ensure effective coverage, the clusters are transformed into shapes that match the coverage areas of the satellite. A technique called Voronoi Tessellation is used to create irregular polygons, and then these polygons are approximated as ellipses to cover the clusters more effectively. [ABSTRACT FROM AUTHOR]

In today's modern and globalized world, connectivity is a key factor for businesses, production facilities, sensor networks, and ordinary people. However, there are still populated areas which are not covered by ground-based telecommunications infrastructure. This is where telecommunication satellite constellations come in, as they can provide coverage to remote and uninhabited regions and fill existing connectivity gaps to ensure data transfer. LoRa is one of the technologies designed for data transmissions over long distances with low power consumption. Alongside with other technologies of the Low-Power Wide Area Network family, it is widely used for Internet of Things applications. LoRa chirp spread spectrum modulation is robust against the Doppler frequency shifts encountered in low earth orbits, and it has already been used in IoT satellite communications. Due to the low transmitted signal power, the achieved data rate is not high, making it a suitable technology for telecommunications payloads on CubeSat platforms for messaging services. As compared to existing traditional communication satellite systems, CubeSat constellations are low-cost and may offer an affordable connectivity service to developing regions. This study is divided in two parts. In Part I the demand model is built based on the population distribution not covered by cell towers. The LoRa link performance is analyzed, considering the impact of LoRa channel parameters variation, such as spreading factor and channel bandwidth, while satellite orbital height, transmission antenna beamwidth, and transmitter peak power have a direct impact on the payload mass. Among thousands of possible configurations, 73 feasible payload designs have been downselected. In Part II of the study, the satellite mass and the total system cost are estimated based on the payload parameters obtained. Messages transmission simulation via a constellation is conducted in order to identify optimal constellation architectures for messaging service, as well as the main drivers of the system economic profitability. The presented analysis results provide a deeper understanding of LoRa connectivity advantages and limitations together with the performance drivers, which will support the optimization of future LoRa-based satellite communication systems and other IoT satellite constellations. • A general framework for communications satellite constellation is suggested. • LoRa technology feasibility for messaging service via satellites has been proved. • LoRa channel capacity is sufficient for 1 message per day per uncovered user. • SF drives achievable channel capacity, orbit height and antenna beamwidth. • 73 payloads were downselected, with 2x2-8x8 patch antennas and transceivers of 1-2W. [ABSTRACT FROM AUTHOR]

The impact of climate change on rainfall patterns poses significant challenges to satellite communication infrastructure. This study explores the dynamic relationship between changing climate conditions and their effects on the reliability and efficiency of satellite communication systems. Utilizing an extensive dataset comprising satellite imagery and meteorological records, this study focuses on discerning the evolving rain height patterns in Malaysia. Rain height is one of the crucial parameters used to determine rain fade on satellite communications. The study employs a statistical methodology including predictive modeling using the regression method, to assess the correlation between climate change-induced alterations in rainfall and the resultant impact on rain height. Our findings reveal a strong correlation between climate change which is typically associated with the increase of global temperature (~ 0.5 °C - 1.5 °C) and rain height (~ 4 m increase per year) in Malaysia. Rain attenuation increases by approximately 0.03 dB per year with the increase of rain height and temperature. The research contributes by revising studies on climate change's effect on rain height with 30 years' worth of meteorological data collected from NOAA. In 2024, the rain height in Malaysia is predicted to be more than 5.4 km. Studies like this one contribute to the effective planning and deployment of satellite communication systems, especially at high-frequency ranges such as Ka and Ku bands, ensuring high-quality and stable communication systems while minimizing loss. [ABSTRACT FROM AUTHOR]

The leverage of satellite resources to establish a communication network offers a wide range of benefits, including the capability to support news gathering, broadcasting, and aeronautical and maritime tracking. The unique aspects of the satellite‐linked terrestrial network provide high‐speed services, dependable and consistent network quality, and comprehensive geographic coverage of remote regions. Unfortunately, these structural features also render the network vulnerable to unauthorized intrusion, potentially leading to significant disruptions. Consequently, the implementation of authentication measures presents an appealing solution for enhancing the overall service quality of this network. Recently, Kumar et al. presented an authentication and key agreement scheme for satellite communications. Strikingly, their scheme proves inadequate in safeguarding against several malicious attacks and reveals certain design weaknesses. In this article, we present a reliable and secure authentication protocol that takes advantage of the complexities inherent in the elliptic curve discrete logarithm problem. We assess the protocol's effectiveness against various types of attacks using formal proof, Burrows–Abadi–Needham logic, informal descriptive proof analysis, and the verification tool SCYTHER. Furthermore, we compare the computational, communication, and storage overhead of our proposed protocol to an existing one, demonstrating its efficiency and superiority. [ABSTRACT FROM AUTHOR]

In this study, we propose a smart transfer planer equipped with multiple antenna arrays to improve ground links for low Earth orbit (LEO) satellite communication. The STP features a symmetrical structure and is strategically placed on both ends of a window, serving both indoor and outdoor environments. Using the window glass as a medium, energy transmission occurs through a coupling mechanism between the planers. The design focuses on large array antenna design, beamforming networks, and coupler design on both sides of the glass. Beamforming networks enable the indoor and outdoor antenna arrays to switch beams in various directions, optimizing high-gain antennas with narrow beamwidths. Through electromagnetic induction and filter couplers, a robust signal transmission channel is established between indoor and outdoor environments. This setup significantly enhances communication efficiency, particularly in non-line-of-sight environments. [ABSTRACT FROM AUTHOR]

In the realm of satellite communication, where the importance of efficient spectrum utilization is growing day by day due to the increasing significance of this technology, dynamic resource management has emerged as a pivotal consideration in the design of contemporary multi-beam satellites, facilitating the flexible allocation of resources based on user demand. This research paper delves into the pivotal role played by machine learning and artificial intelligence within the domain of satellite communication, particularly focusing on spot beam satellites. The study encompasses an evaluation of machine learning’s application, whereby an extensive dataset capturing user demand across a specific geographical area is subjected to analysis. This analysis involves determining the optimal number of beams/clusters, achieved through the utilization of the knee-elbow method predicated on within-cluster sum of squares. Subsequently, the demand data are equitably segmented employing the weighted k-means clustering technique. The proposed solution introduces a straightforward yet efficient model for bandwidth allocation, contrasting with conventional fixed beam illumination models. This approach not only enhances spectrum utilization but also leads to noteworthy power savings, thereby addressing the growing importance of efficient resource management in satellite communication.

In this paper, a broadband circularly polarized (CP) antenna array with stable radiation pattern is proposed for satellite communication applications. The antenna array consists of a 2 $ \times $ × 2 planar antenna array and a feeding network. Based on the magneto-electric (ME) dipole antenna structure, the electric dipoles are modified, and a pair of shorting pins are introduced to adjust the surface current. The bandwidth problems of circular polarization are effectively improved. Then the 2 $ \times $ × 2 broadband CP antenna array is designed and fabricated. The measured results show that the −10 dB impedance bandwidth of 56.3% from 11.1 to 19.79 GHz, and the 3 dB axial ratio (AR) bandwidth of 32.1% from 11.72 to 16.20 GHz. The 3 dB gain bandwidth of 44.2% from 11.10 to 17.40 GHz, and the peak gain is 11.07 dBi. Owing to the above excellent performance, the proposed antenna array can be a candidate for satellite communications. [ABSTRACT FROM AUTHOR]

This paper presents a 2×2 antenna array prototype operating at both uplink and downlink Kubands for satellite applications. The proposed array employs four proximity coupled elliptical antennas fed by three equal Wilkinson power dividers (WPDs) constituting the feeding network. Each antenna element is fed by two parallel connected lines below the major and minor elliptical axes for achieving dual operational bands. For a reflection coefficient (S11) less than -10 dB, the proposed array impedance bandwidth ranges from 11.7 to 12.2 GHz for the downlink and from 14 to 14.96 GHz for the uplink. Over the operational frequency ranges, the suggested array design demonstrates a front-to-back ratio (FBR) ranging between 17 and 20 dB, a radiation efficiency of 86.4 %, and a reakized gain of 11.6 dBi. The antenna array is manufactured, measured, and simulated. The measured and simulated results show good agreement. The suggested array's enhanced performance qualifies it as a viable option for Kuband satellite communications. [ABSTRACT FROM AUTHOR]

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The antenna field of view, the angle range that can be accessed by scanning the main beam of a phased array, is one of the key performance prescriptions especially for space-borne aerials. The classical example of the full Earth, continental and subcontinental field of view of the geosynchronous satellite is indicative, and it extends to the medium and lower orbit multibeam telecommunication systems. There, a high-gain, very small beamwidth pencil beam should scan a given service area. At the same time, it should exhibit extremely low sidelobes in order not to present interference to adjacent geographical areas, served by neighboring beams, and keep its grating lobes out of the Earth's surface. High-throughput telecommunication satellites should comply with those prescriptions to be given permission for placement in orbit. Thus, the motivation for delivering solid methods for the design of limited-field-of-view array antennas is high. A proposal in this direction is presented in the work at hand. Indeed, in the present study a scaling transformation is used to map a wide-angle scanning array to a limited-field-of-view one. We start the design from a Full-Field-of-View array with the appropriate half-power beamwidth, sidelobe level, and directivity index, and then we enlarge it to attain the desired one with the limited-field-of-view pattern characteristics. The potential of the method is solid since it augments the limited-field-of-view design methods using the excellent performance of the respective full-field-of-view ones. As a result, the synthesis of a limited-field-of-view array can use any of the well-known array synthesis methods in conjunction with the right scaling. Additionally, one can employ design methods that rely on sampling of planar aperture distributions. Various design examples, employing both sampling of continuous apertures and utilizing classical full-field-of-view array synthesis methods, are included and presented in detail, verifying the merit of our approach. [ABSTRACT FROM AUTHOR]

Beyond-5G (B5G) technology plays a pivotal role in the next generation of communication infrastructure to support the future Society 5.0, a concept introduced in the 5th Basic Plan for Science and Technology by the Japanese Cabinet to define the long-term growth strategy for reconciling economic development with the resolution of social issues through the promotion of science and technologies. Free-space laser communication is a key element in boosting the data transmission capabilities required for B5G applications. The NICT will complete in 2024 the first fully functional prototypes of a series of miniaturized laser-communication terminals for multiple platforms. These terminals are designed to adapt to a wide range of requirements to address scenarios where laser communications can offer a competitive, enhanced solution compared to existing technologies. This paper provides an overview of these terminals' capabilities and the plans for their functional validation, as well as preliminary data from the first full-system tests. A number of innovations integrated into the terminals are introduced, such as the manufacture of the smallest miniaturized EDFA with integrated HPA and LNA and full space qualification to date, the first-ever integration of a beam-divergence control system in a practical communication terminal, the development of the most compact Tbit/s-class modem prototype documented in the literature, and the smallest gimbal design integrated in a lasercom terminal. Furthermore, this paper outlines the mid-term plans for demonstration in the most significant realistic scenarios, emphasizing the use of High-Altitude Platform Stations (HAPSs) and ultra-small satellites. [ABSTRACT FROM AUTHOR]

From its early days as a fledgling technology, satellite communication has come a long way to become a flourishing component of the global technological ecosystem that determines our increasingly interdependent world. This scholarly essay provides a comprehensive analysis of current developments in satellite communication technology and the several fields in which they might be applied. The essay dives into major inventions that have catapulted this discipline to unparalleled heights, and it spans from the historical origins to the modern accomplishments. This overview elucidates the enormous influence that satellite communication has had on modern civilization, highlighting its central position in allowing global connection, data dissemination, and transformational applications across a variety of industries.