Terrestrial Communication Research Articles

Deep learning based physical layer security for terrestrial communications in 5G and beyond networks: A survey

The key principle of physical layer security (PLS) is to permit the secure transmission of confidential data using efficient signal-processing techniques. Also, deep learning (DL) has emerged as a viable option to address various security concerns and enhance the performance of conventional PLS techniques in wireless networks. DL is a strong data exploration technique which can be used to learn normal and abnormal behavior of 5G and beyond wireless networks in an insecure channel paradigm. Also, since DL techniques can successfully predict future new instances by learning from existing ones, they can successfully predict new attacks, which frequently involve mutations of earlier attacks. Thus, motivated by the benefits of DL and PLS, this survey provides a comprehensive review that overviews how DL-based PLS techniques can be employed for solving various security concerns in 5G and beyond networks. The survey begins with an overview of physical layer threats and security concerns in 5G and beyond networks. Then, we present a detailed analysis of various DL and deep reinforcement learning (DRL) techniques that are applicable to PLS applications. We present the specific use-cases of PLS design for each type of technique, including attack detection, physical layer authentication (PLA), and other PLS techniques. Then, we present an in-depth overview of the key areas of PLS where DL can be used to enhance the security of wireless networks, such as automatic modulation classification (AMC), secure beamforming, PLA, etc. Performance evaluation metrics for DL-based PLS design are subsequently covered. Finally, we provide insights to the readers about various challenges and future research trends in the design of DL-based PLS for terrestrial communications in 5G and beyond networks.

Applications and prospects of artificial intelligence in covert satellite communication: a review

Satellite communication has the characteristics of wide coverage and large communication capacity, and is not easily affected by land disasters. It is quite suitable as a supplement to terrestrial communication networks and has been widely used in education, navigation, emergency relief, military, etc. However, due to the openness of the channel of satellite communication systems, satellite communication signals are easily eavesdropped on by eavesdroppers. This greatly threatens the privacy and security of countries and individuals. Covert satellite communication can effectively improve the covertness of satellite communication systems and greatly reduce the probability of detection by eavesdroppers. So, it has attracted more and more attention. In addition, with the development of artificial intelligence (AI), AI has been applied in many technics of covert satellite communication, which has achieved higher reliability and stronger concealment in covert satellite communication systems. The research status of key technics in covert satellite communication is discussed in this study, and the applications of AI in covert satellite communication are shown. Finally, future research directions of covert satellite communication are looked forward to. In the future, covert satellite communication technology will be an indispensable part of satellite communication systems.

Relay-Aided D2D MIMO Scheme (RAS) for Achieving Energy Efficiency in Satellite-Air-Ground Integrated Networks (SAGIN) Schéma D2D MIMO assisté par relais (RAS) pour atteindre l’efficacité énergétique dans les réseaux intégrés satellite-air-sol (SAGIN)

Space-air-ground integrated network (SAGIN), as a three-tiered architecture that assimilates satellite systems, aerial, and terrestrial communication networks, has become an intensive research domain in the present era of communications. SAGIN-based communication models are developed to enhance the user’s quality of experience (QoE). Besides providing noteworthy benefits in various applications and services, SAGIN has unprecedented challenges because of its self-organized, unpredictable, and heterogeneous nature. Relaying equipment in SAGIN can be a very low-orbit satellite, a base station (BS), and an unmanned vehicle assisting a pair of mobile users’ communications. Thus, developing a robust device-to-device (D2D) direct and relaying communication model concerning channel distribution is crucial. Based on this concern, this article proposes a relay-aided D2D multiple–input and multiple–output (MIMO) scheme (RAS) for enhancing the optimal energy efficiency (EE) as a function of spectral efficiency (SE). The proposed model derives a relay-based amplify-and-forward (AF) MIMO multihop communication system for implementation. The proposed computations of optimal EE and SE for D2D MIMO show that the approximation provided by a random matrix approximation is constrained to a specific signal-to-noise ratio (SNR) range when the optimal SE and EE are derived using Gaussian quadrature and a hypergeometric function.

Radio Technologies for Environment-Aware Wireless Communications

The contemporary wireless transmitter in addition to information symbols transmits also training symbols in order to help the receivers in the estimation of the information symbols by estimating the channel state information (CSI). In this paper, we look at existing wireless communication technologies in light of environment-aware wireless communications, which is a new concept of wireless communications that queries the time-invariant CSI from the local or global database, using information about the transmitter and receiver location. Thus, this study is the first critical review of the potential of today’s terrestrial wireless communication systems including wireless cellular technologies (GSM, UMTS, LTE, NR), wireless local area networks (WLANs), and wireless sensor networks (WSNs), for estimating CSI, the ratio between training and information symbols and the rate of channel variation, and the potential use of time invariable CSI in environment aware wireless communications. The research reveals, that early communication systems provide means for narrowband channel estimation and the CSI is only available as channel attenuation based on signal level measurements. By increasing the frequency bandwidth of communications, the CSI is estimated in some form of channel impulse response (CIR) in almost all currently used radio technologies, but this information is generally not available outside the communication systems. Also, the CSI is estimated only for the channel with active communications. The new radio technology (NR) offers the possibility of estimating the CIR for non-active channels as well, and thus the possibility of initiating environmentally aware wireless communications.

Performance of Reconfigurable-Intelligent-Surface-Assisted Satellite Quasi-Stationary Aircraft–Terrestrial Laser Communication System

This paper proposes the use of quasi-stationary aircraft and reconfigurable intelligent surfaces (RIS) to improve the system performance in satellite–terrestrial laser communication downlink. Single-input multiple-output (SIMO) technology is applied to the relay node of a quasi-stationary aircraft. The closed expression of the bit error rate (BER) of an RIS-assisted satellite quasi-stationary aircraft–terrestrial laser communication system (RIS-SHTLC) is derived under the M-distributed atmospheric turbulence model while considering the influence of atmospheric turbulence and pointing errors caused by RIS jitter. The effects of coherent binary frequency shift keying (CBFSK), coherent binary phase-shift keying (CBPSK), non-coherent binary frequency shift keying (NBFSK), and differential binary phase-shift keying (DBPSK) on the performance of an RIS-SHTLC system are simulated and analyzed under weak turbulence. The results show that the RIS-SHTLC system with CBPSK modulation has the best communication performance. Simultaneously, the relationships between the average signal-to-noise ratio (SNR) and BER of the RIS-SHTLC system under different RIS elements are simulated and analyzed, and compared with the traditional SHTLC system. In addition, the influence of the zenith angle, receiving aperture and divergence angle on the performance of the system is studied. Finally, Monte Carlo simulations are used to validate the analytical results.

Communication for Underwater Sensor Networks: A Comprehensive Summary

Sensing and communication technology has been used successfully in various event monitoring applications over the last two decades, especially in places where long-term manual monitoring is infeasible. However, the major applicability of this technology was mostly limited to terrestrial environments. On the other hand, underwater wireless sensor networks (UWSNs) opens a new space for the remote monitoring of underwater species and faunas, along with communicating with underwater vehicles, submarines, and so on. However, as opposed to terrestrial radio communication, underwater environment brings new challenges for reliable communication due to the high conductivity of the aqueous medium which leads to major signal absorption. In this paper, we provide a detailed technical overview of different underwater communication technologies, namely acoustic, magnetic, and visual light, along with their potentials and challenges in submarine environments. Detailed comparison among these technologies have also been laid out along with their pros and cons using real experimental results.

Performance evaluation of SNB3GEO electrons flux forecasting model using LANL and GOES-13 observations

Energetic electrons in the outer radiation belt can damage the spacecrafts that operate within the region, such as geostationary satellites. For the purpose of terrestrial application, communications, broadcasting and metreological forecast, the existence of geostationary satellites are extremely useful. To provide alerts on the variations and enhancements of relativistic electron fluxes that can damage the spacecrafts, models which predict the relativistic electrons flux need to be accurate enough. In forecasting relativistic electron fluxes, SNB3GEO model provides relatively reliable and easily interpretable prediction output. Although the performance of this model was evaluated with respect to other models (such as Relativistic Electron Forecast Model (REFM)), its prediction accuracy never assessed with respect to experimental measurements except those used in model development (i.e. GOES-12, GOES-13). In this paper, we implemented evaluation of the prediction performance of SNB3GEO using two experimental measurements, which are LANL and GOES-13. The daily averaged relativistic electron flux data from 01 January 2013 to 31 December 2016 have been used to analyze the forecasting performance. Correlation Coefficient (CC), Normalized Root Mean Square Error (NRMSE) and Prediction Efficiency (PE) have been used as performance evaluation quantifier. The results indicated that SNB3GEO provides a more accurate forecast when it is compared with GOES-13 than LANL observations. The four years average values of CC,NRMSE and PE, when the model performance has been evaluated with observations of GOES-13 are 0.896,0.497 and 0.792, respectively, whereas the average values are CC=0.739,NRMSE=0.706 and PE=0.450, when the model performance evaluated with respect to observations of LANL. Such prediction performance evaluation of SNB3GEO will contribute for further improvement of the model used to predict energetic electrons fluxes in Earth’s outer radiation belt.

Deep Learning-Based Authentication Framework for Secure Terrestrial Communications in Next Generation Heterogeneous Networks

Smart Grid (SG) network is growing rapidly to improve the efficiency and reliability of the power supply. It will connect billions of devices to the internet in the near future. This increase in the number of internet-connected devices has led to an exponential increase in the market size of smart meters. These smart meters and devices will generate lakhs of gigabytes of data in upcoming years. To handle this massive amount of data flow, the Information and Communication Technology (ICT) of SG will experience huge advancements in terms of 5G and 6G wireless networks. These networks will provide higher data rates by utilizing the huge bandwidth spectrum of heterogeneous networks (HetNet). As the massive amount of data will be transmitted to various components of the smart grid using the internet, an open channel. Therefore, in addition to the need for high bandwidth and low latency, HetNet security has also become a prime concern. This paper presents an efficient approach to authenticate the smart devices in SG environment by using the channel state information (CSI) of the wireless links. Firstly, Low-Density Parity-Check (LDPC) codes are used to maintain the confidentiality and reliability of data transmission in the Advanced Metering Infrastructure (AMI) of SG. Then, a Convolution Neural Network (CNN)-based authentication framework is proposed to enhance the physical layer security (PLS) of terrestrial communications in next generation SG Hetnets. Further, the proposed framework is evaluated using received Channel State Information (CSI) values from smart meters placed at different locations, while also taking the scenario of active eavesdroppers into account. Experimental analysis reveals that the proposed CNN based authentication achieves 30.76 percent better authentication rate than existing DNN based authentication scheme. Further, the LDPC coded data transmission scheme reduces the bit error rate (BER) by 20 percent as compared to uncoded data transmission.

Artificial Intelligent For Rainfall Estimation In Tropical Region : A Survey

Rainfall monitoring in real-time is a mandatory in tropical areas such as Indonesia. As a country with various topographical conditions ranging from low-lying urban areas, highlands, to mountainous valleys, Indonesia is prone to hydrometeorological disasters in the form of flash floods and landslides. The strategic geographical position at the equator, between the Pacific and Indian oceans, and surrounded by vast oceans, combined with various natural phenomena related to the dynamics of the atmosphere and the ocean, makes high-density rainfall observations indispensable for both disaster mitigation and climate monitoring. As a vast tropical and archipelagic country, Indonesia currently has around 1000 automatic rainfall sensors and still requires more sensors to increase the spatial resolution of the observation network. Increasing the density of the observation network using both rain gauges and weather radar poses a problem of high operational costs. Therefore, several alternative rainfall observation systems are required. In the last decade, there have been several studies related to rainfall measurements using artificial intelligence from various meteorological variables, including the exploitation of microwave signals from radio telecommunications links, both terrestrial and satellite using high frequency bands. In this survey paper, we review and discuss research articles related to rainfall estimation using state-of-the-art methods in artificial intelligence using meteorological observation data, remote sensing, terrestrial and satellite microwave communication links. In conclusion, we present several future research challenges that can be applied to increase the density of rainfall observation networks.

Unmanned Surface Vessel Assisted Maritime Wireless Communication Toward 6G: Opportunities and Challenges

Sixth generation (6G) mobile communication aims to construct an autonomous network architecture with human-like consciousness and intelligence. 6G mobile technology is expected to integrate space, air, ground, and sea networks to provide full-dimensional wireless and ubiquitous coverage. Compared to terrestrial communications, maritime wireless communications are still far behind expectations to satisfy 6G requirements for ubiquitous wireless connectivity and extensive coverage. Fortunately, the unmanned surface vessel (USV) with agile maneuverability and adaptive capability is a potential solution to enhance maritime communication coverage and performance. However, how to apply mobile USVs to maritime wireless communication is still an open issue. In this article, we provide an overview of USV-assisted maritime wireless communication by introducing three typical USV application scenarios, basic networking architecture, andvdesign considerations, as well as the main challenges. An example of USV-assisted mobile relaying is conducted to demonstrate the benefits provided by adopting USV in maritime wireless communication.

Resource Allocation for Networked Telemetry System of Mega LEO Satellite Constellations

In the upcoming 6G communication era, the satellite Internet based on mega constellations will become an indispensable extension of the terrestrial communication network. However, it is difficult for the traditional ground-based and geostationary earth orbit (GEO)-based telemetry systems to satisfy the requirements on monitoring the mega constellation. This paper designs the networked telemetry system, where data is transmitted through the inter-satellite-links (ISL) of the low earth orbit (LEO) and medium earth orbit (MEO) satellites. Furthermore, the resource allocation problem for the networked telemetry system is decomposed using the block coordinate descent method into the access scheduling and the subchannel-power coordinate allocation subproblems, which are iteratively solved to optimize the resource allocation scheme. Finally, the simulation results shows that the proposed resource allocation algorithm effectively increases the transmitted data amount of the system and approximates the upper bound performance.

A Novel RF to Millimeter Waves Frequency Translation Scheme for Ultra-Wideband Beamformers Supporting the Sub-6 GHz Band

This work introduces a new class of ultra-wideband beamforming networks (BFNs) that covers the legacy sub-6 GHz bands for both traditional and fifth-generation (5G) satellite and terrestrial communication systems. To cover the multioctave sub-6 GHz bandwidth, we translate the microwave-photonics concept to the radio frequency (RF)-millimeter waves (mm-waves) regime. Based on our novel approach, the desired RF frequency, a sub-6 GHz signal, is first up-converted to a mm-wave frequency, where it undergoes the desired processing (i.e., the required time delays are introduced), and then it is down-converted back to the initial RF frequency for transmission through the antenna array. An example beamforming system is developed to validate the performance of our proposed approach. Also, a modified true-time-delay (TTD) Blass matrix is designed for this system to perform the analog beamforming. This Blass matrix is prototyped, and its performance is validated using simulations and measurements. Our results show that our proposed BFN supports a 6:1 bandwidth, which is the highest bandwidth ever reported in the literature. Additionally, our proposed approach can be extended to significantly higher bandwidths if high mm-wave frequencies are used in our up-conversion stage.

Secrecy satellite‐terrestrial downlink transmissions against randomly located eavesdroppers

AbstractThe satellite‐terrestrial downlink transmissions with larger coverage areas face more severe security challenges than terrestrial cellular communications due to the limitation of the satellite's power and the complexity of the channel. In this paper, the system model consists of one satellite, one legitimate user and multiple randomly distributed eavesdroppers while taking into account practical hardware impairments (HIs) at all transceivers involved. The Shadowed‐Rician fading model is adopted since it is a perfect fit for the satellite‐terrestrial channel. Besides, the full‐duplex (FD) operation is introduced in the destination where the receiver acquires the information signal and simultaneously emits the artificial noise (AN) to interfere with the nearby eavesdroppers. The maximal ratio combination scheme is applied to the destination to improve security. To facilitate evaluation of the effect of various parameters on the security performance, the closed‐form expressions of secrecy outage probability and ergodic secrecy capacity for the system are derived under the stochastic geometry framework. Finally, the simulation results show that the AN plays a pivotal role in improving the security performance, while the HIs can greatly deteriorate the performance, especially in the high transmit power regime. In addition, compared with the traditional half‐duplex receiver, the FD receiver have better security performance and can significantly alleviate the performance deterioration caused by HIs.

Physical random access signal design for 5G mobile satellite communication systems

In view of the distinctive characteristics of satellite communication, the physical random access signals used in the terrestrial mobile communication system have to be modified or redesigned for the satellite communication system. In this paper, we boost the random access signal energy by repeating the short Zadoff–Chu (ZC) sequence based preamble signal used in the terrestrial system. Different long ZC sequences are used to scramble this cascaded sequence to distinguish different random access signals for multiple random access user equipments. For correlation performance optimization, properties of the roots for both the short and long ZC sequences are mathematically analyzed and derived. Finally, we illustrate how to construct a root set for these different long ZC sequences based on the obtained propositions in a practical way. This analytical framework provides a useful insight into ZC sequence-based random access signal design and performance analysis in mobile satellite communication systems.

Intelligent Reflecting Surface-Aided LEO Satellite Communication: Cooperative Passive Beamforming and Distributed Channel Estimation

Low-earth orbit (LEO) satellite communication plays an important role in assisting/complementing terrestrial communications by providing worldwide coverage, especially in harsh environments such as high seas, mountains, and deserts which are uncovered by terrestrial networks. Traditionally, the passive reflect-array with fixed phase shifts has been applied in satellite communications to compensate for the high path loss due to long propagation distance with low-cost directional beamforming; however, it is unable to flexibly adapt the beamforming direction to dynamic channel conditions. In view of this, we consider in this paper a new intelligent reflecting surface (IRS)-aided LEO satellite communication system, by utilizing the controllable phase shifts of massive passive reflecting elements to achieve flexible beamforming, which copes with the time-varying channel between the high-mobility satellite (SAT) and ground node (GN) cost-effectively. In particular, we propose a new architecture for IRS-aided LEO satellite communication where IRSs are deployed at both sides of the SAT and GN, and study their cooperative passive beamforming (CPB) design over line-of-sight (LoS)-dominant single-reflection and double-reflection channels. Specifically, we jointly optimize the active transmit/receive beamforming at the SAT/GN as well as the CPB at two-sided IRSs to maximize the overall channel gain from the SAT to each GN. Interestingly, we show that under LoS channel conditions, the high-dimensional SAT-GN channel can be decomposed into the outer product of two low-dimensional vectors. By exploiting the decomposed SAT-GN channel, we decouple the original beamforming optimization problem into two simpler subproblems corresponding to the SAT and GN sides, respectively, which are both solved in closed-form. Furthermore, we propose an efficient transmission protocol to conduct channel estimation and beam tracking, which only requires independent processing of the SAT and GN in a distributed manner, thus substantially reducing the implementation complexity. Simulation results validate the performance advantages of the proposed IRS-aided LEO satellite communication system with two-sided cooperative IRSs, as compared to various baseline schemes such as the conventional reflect-array and one-sided IRS.

Electronically Steerable Antennas for Future Heterogeneous Communication Networks: Review and Perspectives

Satellite, fifth generation (5G), and sixth generation (6G) mobile communication systems operating at micro- and millimeter wave frequencies are an essential pillar in advanced network architectures for high-throughput low latency services. The decisive factors for this current development were the significant technological advances accomplished over the last two decades, which meanwhile enable highly integrated, feature-rich, and cost-effective realizations of complete phased array transceiver topologies. Motivated through the today's trend for heterogeneous constellation types to provide truly global coverage, this contribution reviews the current state-of-the-art of electronically steerable antennas for terrestrial and non-terrestrial communication systems up to 100 GHz. First, the potential benefits and limitations of the most relevant technologies are contrasted and put into context with recent system architectures for adaptive beamforming. Their operating principles along with various experimental implementation and achievements providing advanced capabilities such as multi-band/multi-beam operation, polarization agility, and wide-angle scanning are thoroughly presented. Particular emphasis is laid on the review of direct radiating arrays, quasi-optical antenna configurations, and metasurface-based antennas.

Guest Editorial Special Issue on Antenna Array Enabled Space/Air/Ground Communications and Networking

With the rapid development of electronic and information technologies, the Internet of Everything (IoE) has become one of the trendiest topics in both academia and industry. Therein, many types of space/air/ground platforms need to be connected to networks for breaking down the isolation of information islands and providing various services. Space/air/ground platforms, such as satellites, unmanned aerial vehicles (UAVs), airships, balloons, terrestrial vehicles, and high-speed trains (HSTs) have emerged for accomplishing various complex tasks. Wireless communication is one of the most important technologies to support the real-time delivery of control commands and mission-related data. On the other hand, the space-air-ground integrated network has become a promising paradigm for the six-generation (6G) mobile communication network, where the aerospace and terrestrial vehicles may need to connect to existing mobile cellular networks or act as base stations (BSs) or relays to assist terrestrial wireless communications. To meet the ever-increasing demands of high capacity, wide coverage, low latency, and strong robustness for communications, it is promising to adopt large-scale antenna arrays at the transceivers to obtain considerable array gains and improve the channel quality. Antenna array-enabled beamforming technologies can facilitate spectrum reuse, interference mitigation, coverage enhancement, and physical-layer security. Antenna arrays can also be used to promote the sensing capability of space/air/ground networks, where the sensing information may be carefully processed to assist communications. However, enabling antenna array for space/air/ground communication networks poses specific, distinctive, and tricky challenges in antenna array design, physical layer, multiple access control layer, and network layer. As a result, numerous new research issues require to be addressed, which cover a wide range of disciplines including communication theory, network theory, antenna theory, signal processing, protocol design, resource allocation, optimization, hardware implementation, and experimentation.

Comprehensive Performance Analysis of Hovering UAV-Based FSO Communication System

Unmanned-aerial-vehicle (UAV)-based communications are expected to play an important role in the future generation wireless communication networks. It is a promising solution to enhance the wireless connectivity of devices without infrastructure. As compared to the terrestrial communications, UAVs offer various advantages such as line-of-sight (LoS) connectivity, dynamic deployment and flexible reconfiguration. Further, free space optics (FSO) communication is considered as a possible solution to enable UAV-based communication links due to its cost effective and high bandwidth nature. However, despite offering large bandwidth, UAV-based FSO links are marred by atmospheric path loss, atmospheric turbulence, non-zero boresight pointing errors, and angle-of-arrival (AoA) fluctuations. In this paper, the performance of a hovering UAV-based FSO communication system is investigated. The closed-form expressions for outage probability, average symbol error rate (SER), and ergodic capacity are derived taking into account both heterodyne (HD) and direct detection (DD) techniques for ground-to-UAV (G2U), UAV-to-UAV (U2U), and UAV-to-ground (U2G) links over the generalized Málaga distribution. Moreover, the asymptotic expressions for the above performance metrics are also derived to get the diversity gain of the system.

Comparative Computational Study of Double Rotating Cylinder Embedded on Selig S1223 Aerofoil and Flat Plate for High Altitude Platform

The high-altitude platform was built as an alternative approach to address the weakness of the terrestrial and satellite communication networks. It can be an aircraft or balloon positioned 20 to 50 km above the earth’s atmosphere. The use of the Magnus effect was not noticeable in the production of the high-altitude platform, while past research study has denoted its aerodynamic performance in generating greater lift and stall angle delay, which would be beneficial in creating such a flying device. This research delineates the proposed designs using the computational fluid dynamics approach utilizing ANSYS WORKBENCH 2019 software. The embedment of the rotating cylinder onto the design would best portray the use of the Magnus effect in generating higher lift coefficients with probable delay in stall angle. Hereby, the design of embedding rotating cylinder onto Selig S1223 aerofoil and the flat plate is proposed to test their aerodynamic performances for high altitude platform purposes. Here, Fluent fluid flow analysis was simulated for 500 RPM and 1000 RPM momentum injection with free stream velocities from 5 m/s to 30 m/s for different angles of attack of 0 to 20 degrees. The analysis has resulted in a greater impact on its lift coefficient and stall angle delay of about 39% and 53% enhancement for modified aerofoil while showing 128% and 204% betterment for modified flat plate than their respective unmodified model. Therefore, it is perceived that the CyFlaP has better stability yet is simplistic in a design suitable for HAP application.

V/Ka-band LEO high-throughput satellite and integrated satellite–terrestrial network experiment system: First two years flight results

Satellite Internet technology has evolved significantly over the past few years. Low Earth orbit (LEO) satellite communication technology and its applications have received growing interest in the field of global communication, due to their advantages of faster speed, lower latency, higher throughput, etc. GalaxySpace’s first satellite (YINHE-1) has been the world’s first V/Ka-band LEO broadband satellite with a communication capacity of 24 Gbps. The satellite was launched on the 16th of January 2020, and a series of in-orbit tests and satellite–terrestrial communication experiments were carried out within the two years of orbital flight. YINHE-1 is still operating and will participate in subsequent missions developed by GalaxySpace. This paper describes the overall scheme of satellite design and presents an integrated satellite–terrestrial network experiment system. Based on the two-year in-orbit test results, the Q/V band feed beam tracking, throughput and latency, communication under low elevation angles, and user beam switching are evaluated. In addition, the experiment results of integrated satellite–terrestrial communication are analyzed in detail. It is shown that the LEO broadband satellite possesses satisfactory capability in LTE/5G backhaul and Internet applications.