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Impact of Objective Function on Spectral Efficiency in Integrated HAPS-Terrestrial Networks
Integrating non-terrestrial networks (NTNs), in particular high altitude platform stations (HAPS), with terrestrial networks, referred to as vHetNets, emerges as a promising future wireless network architecture for providing ubiquitous connectivity.
Synthetic Waveform Generation for Satellite, HAPS, and 5G Base Station Positioning Reference Signal Using QuaDRiGa
Waveform generation is essential for studying signal propagation and channel characteristics, particularly for objects that are conceptualized but still need to be operational.
Strategic Client Selection to Address Non-IIDness in HAPS-enabled FL Networks
The deployment of federated learning (FL) within vertical heterogeneous networks, such as those enabled by high-altitude platform station (HAPS), offers the opportunity to engage a wide array of clients, each endowed with distinct communication and computational capabilities.
Towards Reliable Participation in UAV-Enabled Federated Edge Learning on Non-IID Data
Federated Learning (FL) is a decentralized machine learning (ML) technique that allows a number of participants to train an ML model collaboratively without having to share their private local datasets with others.
Swarm of Robotic Aerial Base Stations for mmWave Multi-Hop Backhauling
Robotic aerial base stations (RABSs) that are able to anchor at tall urban landforms are expected to bring further flexibility to millimeter-wave (mmWave) multi-hop backhaul networks in highly dense urban environments.
Free-Space Optical (FSO) Satellite Networks Performance Analysis: Transmission Power, Latency, and Outage Probability
For the Toronto--Sydney inter-continental connection in an FSOSN with Starlink's Phase 1 Version 3 constellation, when the LISL range is approximately 2, 900 km, the mean network latency and mean average satellite transmission power intersect are approximately 135 ms and 380 mW, respectively.
Latency versus Transmission Power Trade-off in Free-Space Optical (FSO) Satellite Networks with Multiple Inter-Continental Connections
In the absence of satellite transmission power constraints, as the LISL range extends from the minimum feasible range of 1575 km to the maximum feasible range of 5016 km, the average total network latency decreases from 589 ms to 311 ms.
RL-Based Cargo-UAV Trajectory Planning and Cell Association for Minimum Handoffs, Disconnectivity, and Energy Consumption
Unmanned aerial vehicle (UAV) is a promising technology for last-mile cargo delivery.
Data-Efficient Energy-Aware Participant Selection for UAV-Enabled Federated Learning
Unmanned aerial vehicle (UAV)-enabled edge federated learning (FL) has sparked a rise in research interest as a result of the massive and heterogeneous data collected by UAVs, as well as the privacy concerns related to UAV data transmissions to edge servers.
Outage Performance of Multi-tier UAV Communication with Random Beam Misalignment
In particular, we propose a tractable random model to capture the impacts of beam misalignment in the 3D space.
Enhancing Next-Generation Urban Connectivity: Is the Integrated HAPS-Terrestrial Network a Solution?
Located in the stratospheric layer of Earth's atmosphere, high altitude platform station (HAPS) is a promising network infrastructure, which can bring significant advantages to sixth-generation (6G) and beyond wireless communications systems by forming vertical heterogeneous networks (vHetNets).
Personalized Resource Allocation in Wireless Networks: An AI-Enabled and Big Data-Driven Multi-Objective Optimization
As a result, the use of Artificial Intelligence (AI) is envisioned for wireless network design and optimization due to the flexibility and adaptability it offers in solving extremely complex problems in real-time.
Big-data-driven and AI-based framework to enable personalization in wireless networks
Thus, in this article, we propose the utilization of AI, big data analytics, and real-time non-intrusive user feedback in order to enable the personalization of wireless networks.
Multi-Tier Hierarchical Federated Learning-assisted NTN for Intelligent IoT Services
In the ever-expanding landscape of the IoT, managing the intricate network of interconnected devices presents a fundamental challenge.
Smart Resource Allocation Model via Artificial Intelligence in Software Defined 6G Networks
To this end, we introduce a new metric, i. e., throughput-overhead-complexity (TOC), for the proposed machine learning-based algorithm, which supports a trade-off between these performance indicators.
FLSTRA: Federated Learning in Stratosphere
We propose a federated learning (FL) in stratosphere (FLSTRA) system, where a high altitude platform station (HAPS) facilitates a large number of terrestrial clients to collaboratively learn a global model without sharing the training data.
A Positioning System in an Urban Vertical Heterogeneous Network (VHetNet)
In this paper, we demonstrate the effectiveness of gNBs in improving the vertical positioning accuracy for both the GPS-only system and the HAPS-aided GPS system by analyzing the impact of the density of gNBs and the pseudorange error of gNB on the positioning performance of the gNB augmented positioning systems.
High Altitude Platform Station (HAPS)-Aided GNSS for Urban Areas
In this work, we examine the positioning performance of the High Altitude Platform Station (HAPS)-aided GPS system in an urban area via both simulation and physical experiment.
Analysis of a HAPS-Aided GNSS in Urban Areas using a RAIM Algorithm
In so doing, we examine the positioning performance of a HAPS-aided GPS system in an urban area using both a simulation and physical experiment.
On the Design of Communication-Efficient Federated Learning for Health Monitoring
To tackle this problem, we propose in this paper a communication-efficient federated learning (CEFL) framework that involves clients clustering and transfer learning.
VHetNets for AI and AI for VHetNets: An Anomaly Detection Case Study for Ubiquitous IoT
In this article, we develop an AI-native VHetNets-enabled framework to provide the anomaly detection service for ubiquitous IoT, whose implementation is assisted by intelligent network management functionalities.
Multi-Mode High Altitude Platform Stations (HAPS) for Next Generation Wireless Networks
To tackle this issue, we envision the use of a multi-mode HAPS that can adaptively switch between different modes so as to reduce energy consumption and extend the HAPS loitering time.
Temporary Laser Inter-Satellite Links in Free-Space Optical Satellite Networks
In comparison with the NG-FSOSN, the improvement in latency with the NNG-FSOSN is significant at LISL ranges of 1, 500 km, 1, 700 km, and 2, 500 km, where the improvement is 16. 83 ms, 23. 43 ms, and 18. 20 ms, respectively, for the Sydney-Sao Paulo inter-continental connection.
Handling Interference in Integrated HAPS-Terrestrial Networks through Radio Resource Management
However, the problem of interference is the bottleneck for the optimal operation of such an integrated network.
Resource-Efficient HAPS-RIS Enabled Beyond-Cell Communications
Particularly, unsupported UEs will be connected to a dedicated control station (CS) through RIS-mounted HAPS.
On Crossover Distance for Optical Wireless Satellite Networks and Optical Fiber Terrestrial Networks
It is observed from the numerical results that the crossover distance increases with an increase in the number of hops, and this increase is higher at higher satellite altitudes in OWSNs and lower refractive indexes in OFTNs.
Link Budget Analysis for Free-Space Optical Satellite Networks
The satellites in these FSOSNs will have limited energy and thereby limited power, and we investigate the effect of link distance and link margin on optical inter-satellite link transmission power, and the effect of slant distance, elevation angle, and link margin on optical uplink/downlink transmission power.
A Deep Learning-Based Approach for Cell Outage Compensation in NOMA Networks
Cell outage compensation enables a network to react to a catastrophic cell failure quickly and serve users in the outage zone uninterruptedly.
A Comprehensive Survey of Spectrum Sharing Schemes from a Standardization and Implementation Perspective
As the services and requirements of next-generation wireless networks become increasingly diversified, it is estimated that the current frequency bands of mobile network operators (MNOs) will be unable to cope with the immensity of anticipated demands.
The Digital Divide in Canada and the Role of LEO Satellites in Bridging the Gap
In 2016, the Canadian Radio-television and Telecommunications Commission announced broadband Internet as a basic service available for all Canadians.
When to Crossover from Earth to Space for Lower Latency Data Communications?
Numerical results reveal that a higher refractive index of optical fiber (or $i$) in an OFTN and a lower altitude of satellites (or $h$) in an OWSN result in a shorter crossover distance.
Toward a Smart Resource Allocation Policy via Artificial Intelligence in 6G Networks: Centralized or Decentralized?
In this paper, our aim is to make the network more scalable and more flexible in terms of achievable data rate, overhead, and complexity indicators.
NOMA Computation Over Multi-Access Channels for Multimodal Sensing
This, in return, suggests that our proposed scheme is eminently suitable for multimodal sensor networks.
Cooperation in Space: HAPS-Aided Optical Inter-Satellite Connectivity with Opportunistic Scheduling
Issues with tracking, precision pointing, and Doppler shift are the major sources of performance loss in laser inter-satellite communication that can severely decrease the coverage and overall performance of satellite constellations.
Optical Satellite Eavesdropping
In recent years, satellite communication (SatCom) systems have been widely used for navigation, broadcasting application, disaster recovery, weather sensing, and even spying on the Earth.
UAV-based Crowd Surveillance in Post COVID-19 Era
Consequently, we propose in this paper a complete UAV framework for intelligent monitoring of post COVID-19 outdoor activities.
Optimization of Quantized Phase Shifts for Reconfigurable Smart Surfaces Assisted Communications
Reconfigurable Smart Surface (RSS) is assumed to be a key enabler for future wireless communication systems due to its ability to control the wireless propagation environment and, thus, enhance communications quality.
HAPS Selection for Hybrid RF/FSO Satellite Networks
In the first phase of transmission, the satellite selects the HAPS node that provides the highest signal-to-noise ratio (SNR).
A Weather-Dependent Hybrid RF/FSO Satellite Communication for Improved Power Efficiency
In SatCom, radio-frequency (RF) or free-space optical (FSO) communications can be used depending on the communication environment.
Caching and Computation Offloading in High Altitude Platform Station (HAPS) Assisted Intelligent Transportation Systems
In addition, the caching technique is introduced for network edges to store some of the fundamental data from the HAPS so that large propagation delays can be reduced.
Disconnectivity-Aware Energy-Efficient Cargo-UAV Trajectory Planning with Minimum Handoffs
In this paper, we formulate the trajectory planning as a multi-objective problem aiming to minimize both the UAV's energy consumption and the handoff rate, constrained by the UAV battery size and disconnectivity rate.
Physical Layer Security Framework for Optical Non-Terrestrial Networks
In this work, we propose a new physical layer security framework for optical space networks.
Optical Wireless Satellite Networks versus Optical Fiber Terrestrial Networks: The Latency Perspective
Formed by using laser inter-satellite links (LISLs) among satellites in upcoming low Earth orbit and very low Earth orbit satellite constellations, optical wireless satellite networks (OWSNs), also known as free-space optical satellite networks, can provide a better alternative to existing optical fiber terrestrial networks (OFTNs) for long-distance inter-continental data communications.
HAPS-ITS: Enabling Future ITS Services in Trans-Continental Highways
To this end, high altitude platform station (HAPS) systems, due to their mobility, sustainability, payload capacity, and communication/caching/computing capabilities, are seen as a key enabler of future ITS services for trans-continental highways; this paradigm is referred to as HAPS-ITS.
Securing the Inter-Spacecraft Links: Physical Layer Key Generation from Doppler Frequency Shift
In this work, we propose a secret key generation procedure specifically designed for the inter-spacecraft communication links.
Graph Attention Networks for Channel Estimation in RIS-assisted Satellite IoT Communications
Moreover, bit error rate performance is investigated for RIS designs with discrete and non-uniform phase shifts under channel estimation based on the proposed method.
Laser Inter-Satellite Links in a Starlink Constellation
Then, using satellite constellation for Phase I of Starlink, we study the effect of varying a satellite's LISL range on the number of different types of LISLs it can establish with other satellites.
DeepMuD: Multi-user Detection for Uplink Grant-Free NOMA IoT Networks via Deep Learning
In this letter, we propose a deep learning-aided multi-user detection (DeepMuD) in uplink non-orthogonal multiple access (NOMA) to empower the massive machine-type communication where an offline-trained Long Short-Term Memory (LSTM)-based network is used for multi-user detection.
A Glimpse of Physical Layer Decision Mechanisms: Facts, Challenges, and Remedies
Conventional physical layer decision mechanisms may not meet these requirements, as they are often based on impractical and oversimplifying assumptions that result in a trade-off between complexity and efficiency.
Energy-Efficient RIS-Assisted Satellites for IoT Networks
The use of satellites to provide ubiquitous coverage and connectivity for densely deployed Internet of Things (IoT) networks is expected to be a reality in emerging 6G networks.
Information Theory Information Theory
Group Handover for Drone Base Stations
Mutual authentication, creating a communication channel between terrestrial BS and UxNB, and fast handover operations may cause security issues in the use of UxNB for capacity injection.
Cryptography and Security
Reconfigurable Intelligent Surfaces in Action for Non-Terrestrial Networks
Next-generation communication technology will be made possible by cooperation between terrestrial networks with non-terrestrial networks (NTN) comprised of high-altitude platform stations and satellites.
Channel Estimation for Full-Duplex RIS-assisted HAPS Backhauling with Graph Attention Networks
In this paper, graph attention network (GAT) is firstly utilized for the channel estimation.
Free Space Optics for Next-Generation Satellite Networks
In addition, the optical wireless satellite network that is created by utilizing laser ISLs is examined.
Site Diversity in Downlink Optical Satellite Networks Through Ground Station Selection
Recent advances have shown that satellite communication (SatCom) will be an important enabler for next generation terrestrial networks as it can provide numerous advantages, including global coverage, high speed connectivity, reliability, and instant deployment.
3D Aerial Highway: The Key Enabler of the Retail Industry Transformation
Like highways for cargo trucks, 3D routes in the airspace should be designed for cargo-UAVs to fulfill their operations safely and efficiently.
Energy-Efficient Multi-UAV Data Collection for IoT Networks with Time Deadlines
In the first step, an efficient method is proposed to determine the minimal number of CHs and their best locations.
Low Complexity Soft-Output Faster-than-Nyquist Detector Based on Semidefinite Relaxation
The effectiveness of the proposed soSDR algorithm is evaluated using polar codes with successive cancellation decoding (SCD) through simulations, and its performance is compared against the state-of-the-art techniques from the literature.
Securing the Inter-Spacecraft Links: Doppler Frequency Shift based Physical Layer Key Generation
We propose a novel physical layer secret key generation method for the inter-spacecraft communication links.
Dynamics of Laser-Charged UAVs: A Battery Perspective
Subsequently, using these models, the path planning problem in a particular Internet-of-Things based use-case is revisited from the battery perspective.
Link Budget Analysis for Reconfigurable Smart Surfaces in Aerial Platforms
Specifically, we analyze the characteristics of RSS-equipped aerial platforms and compare their communication performance with that of RSS-assisted terrestrial networks, using standardized channel models.
On the Optimal 3D Placement of a UAV Base Station for Maximal Coverage of UAV Users
Specifically, the 3D placement problem of a directional antenna equipped UAV-BS, aiming to maximize the number of covered aerial users under a spectrum sharing policy with terrestrial networks, is investigated.
Learning Power Control from a Fixed Batch of Data
We address how to exploit power control data, gathered from a monitored environment, for performing power control in an unexplored environment.
Faded-Experience Trust Region Policy Optimization for Model-Free Power Allocation in Interference Channel
Policy gradient reinforcement learning techniques enable an agent to directly learn an optimal action policy through the interactions with the environment.
High Altitude Platform Station based Super Macro Base Station (HAPS-SMBS) Constellations
High altitude platform station (HAPS) systems have recently attracted renewed attention.
Reconfigurable Intelligent Surfaces Empowered THz Communication in LEO Satellite Networks
The revolution in the low Earth orbit (LEO) satellite networks will bring changes on their communication models and a shift from the classical bent-pipe architectures to more sophisticated networking platforms.
Information Theory Signal Processing Information Theory
Aerial Platforms with Reconfigurable Smart Surfaces for 5G and Beyond
In this article, we discuss comprehensive approaches to the integration of RSS in aerial platforms.
Multiple Access in Aerial Networks: From Orthogonal and Non-Orthogonal to Rate-Splitting
In particular, space-division multiple access(SDMA) and power-domain non-orthogonal multiple access (NOMA) present promising multiplexing gains for aerial downlink and uplink.
Non-Orthogonal Multiple Access in the Presence of Additive Generalized Gaussian Noise
The derived PEP expression is subsequently utilized to derive a union bound on the bit error rate (BER) and to quantify the diversity orders realized by NOMA users in the presence of additive white (AW) GGN.
A Prospective Look: Key Enabling Technologies, Applications and Open Research Topics in 6G Networks
To accommodate the stringent requirements of their prospective applications, which are data-driven and defined by extremely low-latency, ultra-reliable, fast and seamless wireless connectivity, research initiatives are currently focusing on a progressive roadmap towards the sixth generation (6G) networks.
Q-Learning Based Aerial Base Station Placement for Fairness Enhancement in Mobile Networks
In this paper, we use an aerial base station (aerial-BS) to enhance fairness in a dynamic environment with user mobility.
Downlink Coverage and Rate Analysis of an Aerial User in Vertical Heterogeneous Networks (VHetNets)
In denser terrestrial networks, the performance at the aerial user degrades substantially despite beamforming.
Low-Complexity Decoder for Overloaded Uniquely Decodable Synchronous CDMA
We consider the problem of designing a low-complexity decoder for antipodal uniquely decodable (UD) /errorless code sets for overloaded synchronous code-division multiple access (CDMA) systems, where the number of signals Kamax is the largest known for the given code length L. In our complexity analysis, we illustrate that compared to maximum-likelihood (ML) decoder, which has an exponential computational complexity for even moderate code lengths, the proposed decoder has a quasi-quadratic computational complexity.
