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Advanced Subsystems and Technologies for Space and Airborne Communication Networks

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A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Sensor Networks".

Deadline for manuscript submissions: 15 May 2024 | Viewed by 25803

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Special Issue Editors

Dr. Francesco Alessio Dicandia

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Guest Editor

Institute of Electronics, Information Engineering and Telecommunications (IEIIT) - National Research Council (CNR), Via Caruso 16, 56126 Pisa, Italy
Interests: antennas; phased arrays; characteristic modes; metamaterials; RFID sensors

Dr. Simone Genovesi

E-Mail Website
Guest Editor

Dipartimento di Ingegneria Dell’Informazione, Università di Pisa, via Caruso 16, 56122 Pisa, Italy
Interests: metamaterials; chipless RFID and sensors; characteristic modes; antenna design; optimization algorithms
Special Issues, Collections and Topics in MDPI journals

Dr. Manlio Bacco

E-Mail Website
Guest Editor

Institute of Information Science and Technologies (ISTI) - National Research Council (CNR), Via G. Moruzzi 1, 56124 Pisa, Italy
Interests: wireless communications; aerospace; IoT communications; CPS; smart farming
Special Issues, Collections and Topics in MDPI journals

Dr. Nelson Fonseca

E-Mail Website
Guest Editor

Antenna and Sub-Millimetre Waves Section, European Space Agency (ESA), Noordwijk, The Netherlands
Interests: antennas; space; wireless communication

Special Issue Information

Dear Colleagues,

The overwhelming growth of wireless communication systems and the requirements for the Internet of Things (IoT) paradigm are stimulating the search for novel solutions to serve the highest possible number of users and manage sensor networks with the required degree of flexibility and scalability. The efforts have pursued solutions relying on terrestrial infrastructures, but also increasingly leveraging Unmanned Aerial Systems (UASs) and space networks. One solution is represented by low Earth orbit (LEO) nanosatellites, which are becoming an appealing option because of the associated capital expenditure (CAPEX) and operating expenditure (OPEX), and because they are more versatile than GEO satellites, as an example. LEO megaconstellations are also appealing due to their ubiquity and versatility, and because they offer the possibility to host ad hoc payloads. Another solution is based on high-altitude platform stations (HAPSs) systems and low-altitude platform stations (LAPSs), which may rely on air balloons or unmanned aerial vehicles (UAVs) providing both seamless and ubiquitous wireless connectivity for the upcoming 5G and beyond wireless systems. Moreover, cooperation between terrestrial infrastructures and aerial base stations forms the basis for the realization of the new airborne communication network (ACN) paradigm.

This Special Issue, which includes both regular research and review articles, aims to disseminate recent advances and technical solutions in the design and development of breakthrough subsystems, ad hoc equipment and implementation for novel wireless communication and sensing architectures.

Dr. Francesco Alessio Dicandia
Prof. Dr. Simone Genovesi
Dr. Manlio Bacco
Dr. Nelson Fonseca
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Antennas, power modules, solar panels, attitude and orbit control for satellites, HAPSs, LAPSs and UAVs
RF front ends
Laser communication
CubeSat constellation, LEO constellation
Massive MIMO, 5G, IoT
Sensor networks
RFID sensors
Camera
Energy harvesting
Damage detection
Disaster management
Environmental monitoring
Machine-to-machine (M2M) communication

Published Papers (11 papers)

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Research

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19 pages, 7601 KiB

Open AccessArticle

Spacecraft Attitude Measurement and Control Using VSMSCSG and Fractional-Order Zeroing Neural Network Adaptive Steering Law

by Lei Li, Yuan Ren, Weijie Wang and Weikun Pang

Sensors 2024, 24(3), 766; https://doi.org/10.3390/s24030766 - 24 Jan 2024

Viewed by 485

Abstract

In order to improve the accuracy and convergence speed of the steering law under the conditions of high dynamics, high bandwidth, and a small deflection angle, and in an effort to improve attitude measurement and control accuracy of the spacecraft, a spacecraft attitude measurement and control method based on variable speed magnetically suspended control sensitive gyroscopes (VSMSCSGs) and the fractional-order zeroing neural network (FO-ZNN) steering law is proposed. First, a VSMSCSG configuration is designed to realize attitude measurement and control integration in which the VSMSCSGs are employed as both actuators and attitude-rate sensors. Second, a novel adaptive steering law using FO-ZNN is designed. The matrix pseudoinverses are replaced by FO-ZNN outputs, which solves the problem of accuracy degradation in the traditional pseudoinverse steering laws due to the complexity of matrix pseudoinverse operations under high dynamics conditions. In addition, the convergence and robustness of the FO-ZNN are proven. The results show that the proposed FO-ZNN converges faster than the traditional zeroing neural network under external disturbances. Finally, a new weighting function containing rotor deflection angles is added to the steering law to ensure that the saturation of the rotor deflection angles can be avoided. Semi-physical simulation results demonstrate the correctness and superiority of the proposed method. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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19 pages, 4766 KiB

Open AccessArticle

Rotating Lorentz Force Magnetic Bearings’ Dynamics Modeling and Adaptive Controller Design

by Feiyu Chen, Weijie Wang and Shengjun Wang

Sensors 2023, 23(20), 8543; https://doi.org/10.3390/s23208543 - 18 Oct 2023

Cited by 1 | Viewed by 736

Abstract

To address the issues of our agile satellites’ poor attitude maneuverability, low pointing stability, and pointing inaccuracy, this paper proposes a new type of stabilized platform based on seven-degree-of-freedom Lorentz force magnetic levitation. Furthermore, in this study, we designed an adaptive controller based on the RBF neural network for the rotating magnetic bearing, which can improve the pointing accuracy of satellite loads. To begin, the advanced features of the new platform are described in comparison with the traditional electromechanical platform, and the structural characteristics and working principle of the platform are clarified. The significance of rotating magnetic bearings in improving load pointing accuracy is also clarified, and its rotor dynamics model is established to provide the input and output equations. The adaptive controller based on the RBF neural network is designed for the needs of high accuracy of the load pointing, high stability, and strong robustness of the system, and the current feedback inner loop is added to improve the system stiffness and rapidity. The final simulation results show that, when compared to the PID controller and robust sliding mode controller, the controller’s pointing accuracy and anti-interference ability are greatly improved, and the system robustness is strong, which can effectively improve the pointing accuracy and pointing stability of the satellite/payload, as well as provide a powerful means of solving related problems in the fields of laser communication, high score detection, and so on. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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14 pages, 406 KiB

Open AccessArticle

User Pairing for Delay-Limited NOMA-Based Satellite Networks with Deep Reinforcement Learning

by Qianfeng Zhang, Kang An, Xiaojuan Yan, Hongxia Xi and Yuli Wang

Sensors 2023, 23(16), 7062; https://doi.org/10.3390/s23167062 - 09 Aug 2023

Cited by 1 | Viewed by 998

Abstract

In this paper, we investigate a user pairing problem in power domain non-orthogonal multiple access (NOMA) scheme-aided satellite networks. In the considered scenario, different satellite applications are assumed with various delay quality-of-service (QoS) requirements, and the concept of effective capacity is employed to characterize the effect of delay QoS limitations on achieved performance. Based on this, our objective was to select users to form a NOMA user pair and utilize resource efficiently. To this end, a power allocation coefficient was firstly obtained by ensuring that the achieved capacity of users with sensitive delay QoS requirements was not less than that achieved with an orthogonal multiple access (OMA) scheme. Then, considering that user selection in a delay-limited NOMA-based satellite network is intractable and non-convex, a deep reinforcement learning (DRL) algorithm was employed for dynamic user selection. Specifically, channel conditions and delay QoS requirements of users were carefully selected as state, and a DRL algorithm was used to search for the optimal user who could achieve the maximum performance with the power allocation factor, to pair with the delay QoS-sensitive user to form a NOMA user pair for each state. Simulation results are provided to demonstrate that the proposed DRL-based user selection scheme can output the optimal action in each time slot and, thus, provide superior performance than that achieved with a random selection strategy and OMA scheme. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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14 pages, 4529 KiB

Open AccessArticle

Fully-Metallic Additively Manufactured Monolithic Double-Ridged Waveguide Rotman Lens in the K/K_a-Band

by Nelson J. G. Fonseca, Sophie-Abigaël Gomanne, José Rico-Fernández, Petar Jankovic, Jaione Galdeano, Giovanni Toso, Piero Angeletti, Manuel Arrebola and Oscar Quevedo-Teruel

Sensors 2023, 23(14), 6573; https://doi.org/10.3390/s23146573 - 21 Jul 2023

Cited by 2 | Viewed by 1205

Abstract

This paper reports on the design and experimental validation of a fully-metallic double-ridged waveguide 10 × 10 Rotman lens additively manufactured as a single part. The wide band operation of this quasi-optical beamformer enables us to cover the uplink and downlink frequencies allocated [...] Read more.

_{a}

-band, from 17.3 GHz to 30 GHz. The feeding port design was adjusted to enable vertical printing, thus minimizing the use of supporting structures. A prototype was manufactured and tested. The reported results indicate losses in the range of 0.5 dB in the lower-frequency band and 0.8 dB in the upper-frequency band, including the waveguide transitions added for test purposes. The measured reflection and coupling coefficients remain below −11.5 dB over the operating band. The standard deviation of the residual phase error across the array ports is below

5 °

in simulation and below

10 °

in measurements. Array factors synthesized using the scattering parameters confirm the good stability of the beamforming functionality over the wide frequency band analyzed. This monolithic design is a promising step toward more integrated antenna systems, such as a compact dual-stack configuration for planar array design. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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15 pages, 2260 KiB

Open AccessArticle

Compact UHF Circularly Polarized Multi-Band Quadrifilar Antenna for CubeSat

by Manh Thao Nguyen, Fabien Ferrero and Le-Huy Trinh

Sensors 2023, 23(12), 5361; https://doi.org/10.3390/s23125361 - 06 Jun 2023

Cited by 2 | Viewed by 1648

Abstract

This article presents a multi-band right-hand circularly polarized antenna designed for the Cube Satellite (CubeSat). Based on a quadrifilar structure, the antenna provides circular polarization radiation suitable for satellite communication. Moreover, the antenna is designed and fabricated using two 1.6 mm thickness FR4-Epoxy boards connected by metal pins. In order to improve the robustness, a ceramic spacer is placed in the centerboard, and four screws are added at the corners to fix the antenna to the CubeSat structure. These additional parts reduce antenna damage caused by vibrations in the launch vehicle lift-off stage. The proposal has a dimension of 77 × 77 × 10 mm³ and covers the LoRa frequency bands at 868 MHz, 915 MHz, and 923 MHz. According to the measurements in the anechoic chamber, antenna gains with the values of 2.3 dBic and 1.1 dBic are obtained for the 870 MHz and 920 MHz, respectively. Finally, the antenna is integrated into a 3U CubeSat that was launched by a Soyuz launch vehicle in September 2020. The terrestrial-to-space communication link was measured, and the antenna performance was confirmed in a real-life scenario. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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26 pages, 8700 KiB

Open AccessArticle

Prioritization Based Task Offloading in UAV-Assisted Edge Networks

by Onur Kalinagac, Gürkan Gür and Fatih Alagöz

Sensors 2023, 23(5), 2375; https://doi.org/10.3390/s23052375 - 21 Feb 2023

Viewed by 1889

Abstract

Under demanding operational conditions such as traffic surges, coverage issues, and low latency requirements, terrestrial networks may become inadequate to provide the expected service levels to users and applications. Moreover, when natural disasters or physical calamities occur, the existing network infrastructure may collapse, leading to formidable challenges for emergency communications in the area served. In order to provide wireless connectivity as well as facilitate a capacity boost under transient high service load situations, a substitute or auxiliary fast-deployable network is needed. Unmanned Aerial Vehicle (UAV) networks are well suited for such needs thanks to their high mobility and flexibility. In this work, we consider an edge network consisting of UAVs equipped with wireless access points. These software-defined network nodes serve a latency-sensitive workload of mobile users in an edge-to-cloud continuum setting. We investigate prioritization-based task offloading to support prioritized services in this on-demand aerial network. To serve this end, we construct an offloading management optimization model to minimize the overall penalty due to priority-weighted delay against task deadlines. Since the defined assignment problem is NP-hard, we also propose three heuristic algorithms as well as a branch and bound style quasi-optimal task offloading algorithm and investigate how the system performs under different operating conditions by conducting simulation-based experiments. Moreover, we made an open-source contribution to Mininet-WiFi to have independent Wi-Fi mediums, which were compulsory for simultaneous packet transfers on different Wi-Fi mediums. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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10 pages, 1331 KiB

Open AccessArticle

Very Compact Waveguide Orthomode Transducer in the K-Band for Broadband Communication Satellite Array Antennas

by Nelson J. G. Fonseca

Sensors 2023, 23(2), 735; https://doi.org/10.3390/s23020735 - 09 Jan 2023

Viewed by 2131

Abstract

A very compact waveguide orthomode transducer (OMT) is described in this paper. The design is characterized with a twofold rotationally symmetric cross-section in the probing area, adapted from a side-coupling OMT design, simultaneously enabling low port-to-port coupling and high cross-polarization discrimination (XPD) over a fractional bandwidth of about 15–20%. Compared to previously reported compact waveguide OMTs, the proposed design is simpler, thus facilitating its manufacture at millimeter-wave frequencies. The concept is demonstrated with a design in the K-band for a broadband communication satellite downlink over the frequency band of 17.3–20.2 GHz. For test purposes, transitions to standard waveguide WR42 are included, and the OMT is assembled with a conical horn antenna. The measured reflection and coupling coefficients are below −19.5 dB and −22.9 dB, respectively, over the nominal bandwidth, and they are in good agreement with the simulation’s results. The on-axis XPD, measured in an anechoic chamber, is better than 30 dB over the nominal bandwidth, which is also in line with simulations. The proposed waveguide OMT may be designed to fit in a lattice below one wavelength at the highest operating frequency, which is desirable for dual-polarized closely spaced array antennas in low and medium Earth orbit communication satellite systems. The simple mechanical design of the proposed OMT makes it particularly appealing for additive manufacturing techniques, as demonstrated with a variant of the design having folded single-mode waveguides, which preserves the RF properties of the original design. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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15 pages, 3295 KiB

Open AccessArticle

Machine Learning-Based Air-to-Ground Channel Model Selection Method for UAV Communications Using Digital Surface Model Data

by Young-Eun Kang and Young-Ho Jung

Sensors 2022, 22(23), 9234; https://doi.org/10.3390/s22239234 - 27 Nov 2022

Viewed by 1428

Abstract

This paper proposes an automatic air-to-ground (A2G) channel model selection method based on machine learning (ML) using digital surface model (DSM) terrain data. In order to verify whether a communication network for a new non-terrestrial user service such as Urban Air Mobility (UAM) satisfies the required performance, it is necessary to perform a simulation reflecting the characteristics of the corresponding terrain environments as accurately as possible. For this simulation, A2G channel models corresponding to various terrain environments and a method of automatically classifying the terrain type of the simulation area must be provided. Many A2G channel models based on actual measurement results exist, but the practical automatic topography classification method still needs to be developed. This paper proposes the first practical automatic topography classification method using a two-step neural network-based classifier utilizing various geographic feature data as input. Since there is no open topography dataset to evaluate the accuracy of the proposed method, we built a new dataset for five topography classes that reflect the characteristics of Korea’s topography, which is also a contribution of our study. The simulation results using the new data set show that the proposed ML-based method could increase the selection accuracy compared to the technique for direct classification by humans or the existing cross-correlation-based classification method. Since the proposed method utilizes the DSM data, open to the public, it can easily reflect the different terrain characteristics of each country. Therefore, the proposed method can be effectively used in the realistic performance evaluation of new non-terrestrial communication networks utilizing vast airspace such as UAM or 6G mobile communications. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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21 pages, 952 KiB

Open AccessArticle

Closed-Form Power Normalization Methods for a Satellite MIMO System

by Andrea Segneri, Alejandro Baldominos, George Goussetis, Alberto Mengali and Nelson J. G. Fonseca

Sensors 2022, 22(7), 2586; https://doi.org/10.3390/s22072586 - 28 Mar 2022

Cited by 1 | Viewed by 1805

Abstract

The paper proposes a new set of normalization techniques for precoding/beamforming matrices applicable to broadband multiuser multiple-input multiple-output (MIMO) satellite systems. The proposed techniques adapt known normalization methods to account for the signal attenuation experienced by users due to the degradation of antenna gain and free space losses towards the edge of the coverage. We use, as an example, an array-fed reflector (AFR) antenna onboard a satellite in geosynchronous orbit (GEO), which provides a favorable trade-off between high-directivity, reconfigurability, and the requirement for digital processing, but suffers from high scan losses away from broadside due to optical aberrations when considered for global coverage applications. Three different precoding/beamforming techniques are employed, namely zero forcing (ZF), minimum mean squared error (MMSE), and matched filtering (MF). Low-complexity power normalization techniques digitally applied after the beamformer are introduced that, in the absence of any atmospheric effects, lead to iso-flux-like characteristics whilst satisfying the power constraint per feed. In comparison with other methods reported in the literature, mainly based on iterative algorithms, the proposed techniques consist in closed-form expressions to provide uniform signal-to-noise ratio (SNR) and signal-to-noise plus interference ratio (SNIR) across the users without significant impact on the payload sum rate. Numerical results are presented to comparatively demonstrate the achieved performance in terms of total capacity and distribution of SNR and SNIR at various noise and interference scenarios. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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21 pages, 5182 KiB

Open AccessArticle

Coexistence of Satellite Ground Stations in Teleport Facilities: Interference Assessment, Real Application Scenario and Measurements

by Nektarios Moraitis and Athanasios D. Panagopoulos

Sensors 2022, 22(3), 1234; https://doi.org/10.3390/s22031234 - 06 Feb 2022

Viewed by 2235

Abstract

This article introduces a unified and detailed methodology for interference assessment between coexisting fixed satellite service (FSS) and broadcast satellite service (BSS) with spectrum sharing at the Ka-band. The interference analysis is presented along with a step-by-step algorithm for the calculation of the carrier-to-interference ratio (CIR). The proposed procedure takes into consideration the near-field effect of ground-satellite-terminal antennas since these may reside at very close distances. Furthermore, numerical results are delivered so as to assess the CIR in relation to the relative geometry and the technical characteristics of the satellite terminals. A real application scenario is also provided along with measurements so as to validate the recommended methodology. Finally, mitigation techniques are proposed for the protection of the victim stations and operation under harmful interference conditions. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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Review

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34 pages, 4131 KiB

Open AccessReview

Space-Air-Ground Integrated 6G Wireless Communication Networks: A Review of Antenna Technologies and Application Scenarios

by Francesco Alessio Dicandia, Nelson J. G. Fonseca, Manlio Bacco, Sara Mugnaini and Simone Genovesi

Sensors 2022, 22(9), 3136; https://doi.org/10.3390/s22093136 - 20 Apr 2022

Cited by 47 | Viewed by 9699

Abstract

A review of technological solutions and advances in the framework of a Vertical Heterogeneous Network (VHetNet) integrating satellite, airborne and terrestrial networks is presented. The disruptive features and challenges offered by a fruitful cooperation among these segments within a ubiquitous and seamless wireless connectivity are described. The available technologies and the key research directions for achieving global wireless coverage by considering all these layers are thoroughly discussed. Emphasis is placed on the available antenna systems in satellite, airborne and ground layers by highlighting strengths and weakness and by providing some interesting trends in research. A summary of the most suitable applicative scenarios for future 6G wireless communications are finally illustrated. Full article

(This article belongs to the Special Issue Advanced Subsystems and Technologies for Space and Airborne Communication Networks)

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