Next Generation Wireless Communication: Advances in Optical, mm-Wave, and THz Technologies

Preface
Contents
Part I Millimeter Wave (mm-Wave) Technology and Its Applications
1 Compact MIMO Antenna Design with Enhanced Isolation for mm-Wave Applications
	1.1 Introduction
	1.2 MIMO Antenna Design
	1.3 Results and Discussions
	1.4 Conclusion
	References
2 Security Threats and Privacy Challenges in Millimeter-Wave Communications
	2.1 Introduction
		2.1.1 Evolution of mmWave Communications
		2.1.2 Scope and Significance of Security Threats
		2.1.3 Privacy Challenges in mmWave Networks
	2.2 Security Threats in mmWave Communications
		2.2.1 Eavesdropping and Interception
		2.2.2 Man-in-the-Middle Attacks
		2.2.3 Denial-of-Service (DoS) Attacks
		2.2.4 Physical Layer Attacks
		2.2.5 Authentication and Authorization Vulnerabilities
	2.3 Privacy Concerns in mmWave Networks
		2.3.1 Location Tracking and Profiling
		2.3.2 Data Breaches and Information Leakage
		2.3.3 Identity Theft and Impersonation
	2.4 Vulnerabilities and Exploitable Weaknesses
		2.4.1 Beamforming and Signal Interception
		2.4.2 Spectrum Sharing and Frequency Hijacking
		2.4.3 Inadequate Authentication Mechanisms
		2.4.4 Lack of Standardized Security Protocols
	2.5 Mitigation Strategies for Security Threats
		2.5.1 Encryption and Cryptographic Techniques
		2.5.2 Secure Key Exchange Protocols
		2.5.3 Intrusion Detection and Prevention Systems
		2.5.4 Enhanced Authentication Mechanisms
		2.5.5 Spectrum Management and Dynamic Frequency Allocation
	2.6 Future Perspectives and Emerging Trends
		2.6.1 Advancements in mmWave Security Solutions
		2.6.2 Integration of AI and Machine Learning for Threat Detection
		2.6.3 Evolving Privacy Standards and Policies
		2.6.4 Anticipated Challenges in Next-Generation mmWave Networks
	2.7 Conclusion
	References
3 The Performance Analysis on Channel Estimation in Millimeter-Wave Communication and Their Challenges
	3.1 Introduction
	3.2 System Model
		3.2.1 Problem Formulation
	3.3 Iterative Methods
		3.3.1 Approximate Message Passing (AMP) Algorithm
		3.3.2 Learned Approximate Message Passing (AMP) Algorithm
		3.3.3 Learning the LAMP Parameters
		3.3.4 Vector Approximate Message Passing (VAMP) Algorithm
		3.3.5 EM-VAMP Algorithm
	3.4 Proposed VAMP-SBL-EM Algorithm
	3.5 Simulation
	3.6 Conclusion
	References
4 Innovative mm-Wave Compact Dual-Port MIMO Antenna with Inherent Wideband Isolation at 28 GHz for 5G Wireless Networks
	4.1 Introduction
	4.2 Structure and Performance Analysis of the Submitted Individual Antenna
		4.2.1 Submitted Antenna Layout
		4.2.2 Antenna Evolutionary Phases
		4.2.3 Exploration of Trapezoidal Slot Parameters Through Comprehensive Analysis
		4.2.4 Findings and Analysis
	4.3 Antenna Configuration in MIMO Composition
		4.3.1 Layout and Scattering Parameters
		4.3.2 Characteristics of Diversity
		4.3.3 Evaluation Through Relevant Earlier Research
	4.4 Conclusion
	References
5 Design of Ka-Band Power Amplifier and Low-Noise Amplifier for 5G Communication Systems
	5.1 Introduction
		5.1.1 Power Amplifier
		5.1.2 Low-Noise Amplifier
		5.1.3 GaN HEMT
		5.1.4 Objective
	5.2 Literature Survey
		5.2.1 5G RF Front End
		5.2.2 Power Amplifier
		5.2.3 Low-Noise Amplifier
		5.2.4 Biasing Network
	5.3 Design of Power Amplifier
		5.3.1 Design Consideration
		5.3.2 Proposed Power Amplifier Using UMS GH15-10
	5.4 Low-Noise Amplifier
		5.4.1 Design Consideration
		5.4.2 Proposed Low-Noise Amplifier Design Using UMS GH15-10
	5.5 Summary
	References
6 Advanced MIMO Antenna Design with Defected Ground Structure for 5G NR (N75 and N77) Applications
	6.1 Introduction
	6.2 Geometry of the MIMO System
	6.3 MIMO Analysis
	6.4 Conclusion
	References
7 Beamforming Array Failure Correction for mm-Wave Synthetic Aperture Radar Applications
	7.1 Introduction
		7.1.1 Significance of Cosecant 4th Power Pattern
		7.1.2 Element Failure
	7.2 Literature Review
		7.2.1 Software-Based Antenna Array Element Failure Correction Techniques
	7.3 Microstrip Patch Series-Fed Antenna
	7.4 Proposed Genetic Algorithm for Element Failure Correction
	7.5 Results and Discussion
	7.6 Summary
	Appendix
	References
8 A Novel, Compact, Broadband Band-Stop Filter for Rejecting 5G Millimeter-Wave Communications
	8.1 Introduction
	8.2 Fundamentals of Filters
		8.2.1 Filter Categories
		8.2.2 Filter Classes
		8.2.3 Importance of Filters in Communication Systems
		8.2.4 Filtenna
	8.3 Fundamentals of Filters
		8.3.1 Types of Band-Stop Filters
		8.3.2 Characteristics of Band-Stop Filters
		8.3.3 Applications and Uses
	8.4 Design and Analysis of a Band-Stop Filter
		8.4.1 Parametric Study
		8.4.2 Band-Stop Filter Equivalent Circuit
	8.5 Conclusion
	References
9 A Compact Two-Port Semi-flexible Dual-Band Circularly Polarized MIMO Antenna Structure for Millimeter-Wave 26/31 GHz 5G Applications
	9.1 Introduction
	9.2 MIMO Antenna Design and Discussion
	9.3 Simulated Results and Discussion
		9.3.1 Impedance Characteristics
		9.3.2 Bending Analysis
		9.3.3 Radiation Characteristics
		9.3.4 Diversity Performance
	9.4 Conclusion
	References
10 Extension of Indoor MmW Link Radio Coverage in Non-line-of-Sight Conditions
	10.1 Introduction
	10.2 Propagation Using Passive Reflectors at 60 GHz
		10.2.1 Use of a Passive Reflector in an L-Shaped Corridor
		10.2.2 Use of a Passive Reflector Array in a T-Shaped Corridor
	10.3 Impact of Blocking by the Human Body at 60 GHz
		10.3.1 Measurement Environment
		10.3.2 Measurement Scenario
		10.3.3 Measurement Results
	10.4 Conclusions
	References
11 Design and Analysis of Conformal Millimeter Wave Antenna for Next Generation Wireless Communication
	11.1 Introduction
	11.2 Design of Conformal Antenna Array
	11.3 Result and Discussion
	11.4 Conclusion
	References
12 H-Shaped Resonators for UWB Bandpass Filter for 5G Applications
	12.1 Introduction
	12.2 Overview of Filters
	12.3 The First Bandpass Filter
	12.4 The Second Bandpass Filter
	12.5 The Proposed UWB Bandpass Filter
	12.6 Conclusion
	References
13 Spatially Correlated Channels Investigation: Estimation and Hardening in Millimeter-Wave Massive MIMO Systems
	13.1 Introduction
	13.2 Related Works
		13.2.1 Work Organization
	13.3 System Model
		13.3.1 Pilots Sequence Phase
	13.4 Channel Estimation
	13.5 Channel Hardening
	13.6 Spatial Correlation Matrix
		13.6.1 Spatial Correlation Matrix Over ULC
		13.6.2 Spatial Correlation Matrix Over UCC
	13.7 Simulation Results
	13.8 Conclusion
	References
Part II Terahertz Technology and Its Applications
14 THz Antennas: Applications and Challenges—A Review
	14.1 Introduction
	14.2 Single THz Antenna
	14.3 Array THz Antenna
	14.4 MIMO THz Antenna
	14.5 THz Antenna’s Challenges
	14.6 Conclusion
	References
15 Fractal MIMO Antenna Design for High-Frequency Terahertz Applications
	15.1 Introduction
	15.2 Antenna Geometry
	15.3 Results Explanation
	15.4 MIMO Parameters
	15.5 Conclusion
	References
16 Evaluating the Performance of a Transparent MIMO Nano-Antenna for Wireless Health: Addressing Terahertz Challenges in Integrated Medical Device Networks
	16.1 Introduction
	16.2 Related Works
	16.3 Antenna Characteristics
		16.3.1 AI-Enhanced Antenna Radiation Pattern Optimization
		16.3.2 Enhancing Antenna Gain with Artificial Intelligence
		16.3.3 Antenna Selection Factors
		16.3.4 Key Antenna Parameters and Practical Design Guidelines
	16.4 MIMO Nano-Antenna
	16.5 Performance Analysis and Discussion
	16.6 Conclusion
	References
17 Design of a Broadband (0.84–1.2 THz) Microstrip Patch Antenna Utilizing Graphene Material and Polyimide Substrate for Terahertz 6G Applications
	17.1 Introduction
	17.2 Presentation of Graphene
	17.3 Design of the Proposed Graphene Patch Antenna
	17.4 Simulation Results and Discussion
	17.5 Comparison Analysis
	17.6 Conclusion
	References
18 Investigation on LP-OFDM for THz Application
	18.1 Introduction
	18.2 The LP-OFDM System
		18.2.1 Description of the LP-OFDM
		18.2.2 LP-OFDM Signal Expressions
		18.2.3 The Choice of the Linear Precoding Matrix
		18.2.4 Receiving LP-OFDM Signals
		18.2.5 Characteristics of an LP-OFDM Signal
	18.3 Formulation of the BER Maximization Problem
		18.3.1 The Classic Method
		18.3.2 Improvement of the LP-LCG Method
	18.4 Simulation Results and Discussion
		18.4.1 Performance of the Proposed System
		18.4.2 Comparison of the Different Solutions
	18.5 Conclusion
	References
19 Terahertz Technology and Its Importance in the Field of Biomedical Application: A Review
	19.1 Introduction
	19.2 Terahertz Technology: A Historical Perspective
		19.2.1 Early Research
		19.2.2 Key Developments in 1980s–1990s
		19.2.3 Applications and Progress in 2000s–2010s
		19.2.4 Advancements in Terahertz Technology Post-2010
		19.2.5 Major Advancements 2010–2023
	19.3 Biomedical Applications of Terahertz Technology
		19.3.1 Terahertz Imaging
		19.3.2 Advantages of THz for Heart Attack Detection
		19.3.3 Terahertz Spectroscopy for Disease Diagnosis
		19.3.4 Advantages of Terahertz Technology in Brain Tumour Detection
	19.4 Importance of Terahertz Technology in Biomedicine
	19.5 Case Studies: Terahertz Technology in Biomedical Research
	19.6 Challenges and Limitations of Terahertz Technology in Biomedical Application
		19.6.1 Technical Challenges
		19.6.2 Ethical Challenges
		19.6.3 Regulatory Challenges
		19.6.4 Cost Challenges
		19.6.5 Integration Challenges
	19.7 Conclusion
	References
20 Design and Analysis of Frequency Selective Surface for Gain Enhancement in Terahertz Applications
	20.1 Introduction
	20.2 Unit Cell and Frequency Selective Surface Geometry
	20.3 Conclusion
	References
21 Terahertz Waves in Biomedicine: Pioneering Imaging and Sensing for Healthcare Revolution
	21.1 Introduction
		21.1.1 The Terahertz Frequency Range in Biomedical Application
		21.1.2 Non-ionizing Attributes and Material Penetration
	21.2 Interaction of Materials with Terahertz Waves
		21.2.1 Penetration of Plastics, Clothing, and Ceramics
		21.2.2 Water Absorption and Contrast in Biological Tissues
	21.3 Terahertz in Imaging Applications
		21.3.1 Cancer Identification
		21.3.2 Skin Imaging
		21.3.3 Wound Healing Assessment
	21.4 Terahertz Sensing Applications
		21.4.1 Pharmaceutical Analysis
		21.4.2 Bimolecular Sensing
		21.4.3 Monitoring Water Content
	21.5 Challenges and Ongoing Developments
		21.5.1 Resolution, Signal-to-Noise Ratio, and Instrumentation Complexity
		21.5.2 Advancements in Terahertz Time-Domain Imaging (THz-TDI)
		21.5.3 Exploration of Terahertz-Computed Tomography (THz-CT)
		21.5.4 Therapeutic Potential: Selective Heating and Cellular Modulation
		21.5.5 Advancements in Terahertz Sources and Detectors: Toward Miniaturization
	21.6 Future Prospects
	21.7 Conclusion
	References
22 The Analog Design of a Voltage Generator in 180 nm CMOS Technology
	22.1 Introduction
	22.2 Architecture
		22.2.1 Rectifier
		22.2.2 Voltage Regulator
	22.3 Results and Discussions
		22.3.1 Voltage Rectifier Circuit
		22.3.2 Voltage Regulator Circuit
		22.3.3 Rectifier and Regulator Circuit
	22.4 Conclusion
	References
23 Satellite and Terrestrial Mobile Integration-Potential and Open Issues for 5G and Terahertz Communication
	23.1 Introduction
	23.2 Related Work
	23.3 Non-terrestrial Networks (NTN)
		23.3.1 General Architecture
		23.3.2 Unmanned Aerial Vehicle (UAV)
		23.3.3 High Altitude Platform (HAP)
	23.4 Necessity of Integration
		23.4.1 Use in Enhanced Mobile Broadband (eMBB)
		23.4.2 Use for Massive Machine-Type Communication (mMTC)
		23.4.3 Application in Ultra-reliable Low Latency Communication (uRLLC)
	23.5 How the Integration is Done?
	23.6 Challenges
		23.6.1 Use in eMBB
		23.6.2 Spectrum Scarcity
		23.6.3 Satellite Propagation Delay
		23.6.4 Doppler Effect
		23.6.5 Security
	23.7 Air Interface Key Enablers
		23.7.1 Channel Modeling
		23.7.2 Antennas
		23.7.3 Ultra-high Throughput Satellites (UHTS)
		23.7.4 Data Support
		23.7.5 Others
	23.8 Applications
	23.9 Results and Discussions
	23.10 Future Direction
	23.11 Conclusion
	References
24 Design of an Image Frequency Rejection Mixer for the Terahertz Band
	24.1 Receiver System Architectures
	24.2 Theoretical Study of the Mixer
		24.2.1 Operating Principle
		24.2.2 Mixer Performance
		24.2.3 Simply Balanced Mixer (SBM) Architecture
	24.3 Design of a pHEMT Mixer for the THz Band
		24.3.1 Mixer Bias Circuit
		24.3.2 Improving SBM Performance with Charge Injection
		24.3.3 SBM Performance with a Serial Shunt Point
	24.4 Comparison of Results
	24.5 Conclusion
	References
25 Spatially Efficient MIMO Antenna Design Using Photonic Crystal and Polyimide Substrate
	25.1 Introduction
	25.2 Antenna Geometry
	25.3 Results Analysis
	25.4 Analysis of Diversity Parameters
	25.5 Conclusion
	References
26 Modeling Terahertz Patch Antenna Using the Wave Concept Iterative Process in Frequency Range 6–15 THz
	26.1 Introduction
	26.2 Problem Formulation
		26.2.1 Patch Antenna Geometry
		26.2.2 Theory of Wave Concept Iterative Method
	26.3 Results and Discussion
		26.3.1 Analysis of the Patch Antenna
	26.4 Conclusion
	References
27 Study and Design of a Printed Microstrip Antenna in the Terahertz Band
	27.1 Introduction
	27.2 Properties, Characteristics and Typical Applications of Terahertz Waves
		27.2.1 Definition
		27.2.2 General Description of the Frequency Range Above 275 GHz
		27.2.3 Characteristics of the Frequency Range Above 275 GHz
		27.2.4 Main Applications of Terahertz Waves
		27.2.5 Terahertz Wireless Communications
		27.2.6 Properties
		27.2.7 Terahertz Electromagnetic-Wave Detectors
	27.3 Printed Antenna for THz Frequencies
		27.3.1 What is an Antenna?
		27.3.2 The Printed or Patch Antenna
		27.3.3 Printed Antenna Design Operates at 300 GHz
	27.4 Results of the Simulation and Discussion
	27.5 Conclusion
	References
Part III Advances in Materials for Optical Spectrum Applications
28 Graphene-Based Nanomaterials for Photosensitive Spectrum Applications: An Inclusive Review
	28.1 Introduction
		28.1.1 Background of the Study
		28.1.2 Structure of Graphene and Graphene-Based Nanomaterial
	28.2 Graphene Synthesis Technique
		28.2.1 Exfoliation Process
		28.2.2 Graphene by Adhesive Tape Method
		28.2.3 Graphene-Oxide Reduction
		28.2.4 Shearing
		28.2.5 Graphene by Solvent-Aided Process
		28.2.6 Graphene by Using Immiscible Liquids
		28.2.7 Electrochemical Syntheses
		28.2.8 Graphene by Hydrothermal Self-Assemble Process
		28.2.9 Epitaxy
		28.2.10 Microwave-Assisted Reduction
		28.2.11 Chemical Vapor Deposition
	28.3 Graphite Powder to Graphene Oxide Journey
	28.4 Overview of Graphene Nanocomposite
	28.5 In Optical Field
	28.6 Various Applications
		28.6.1 Graphene as Transparency Conductive Films
		28.6.2 Light-Emitting Devices
		28.6.3 Graphene Optical Modulator
		28.6.4 Graphene in IR Application
		28.6.5 Graphene in IR Photodetector
		28.6.6 Graphene Plasmonics: IR Advancements
		28.6.7 Graphene IR Metamaterial Advancement
		28.6.8 Graphene in THz Optics
	28.7 Conclusion Outlook and Remarks
	References
29 Conducting Polymer Coated Nanomaterial: An Advanced Material for Optoelectronic Devices
	29.1 Introduction
	29.2 Advanced Materials
		29.2.1 Polyaniline (PANI)
		29.2.2 Polypyrrole
		29.2.3 Inorganic Organic Hybrid Nanomaterial
	29.3 Synthesis
	29.4 Characterization
		29.4.1 Morphology
		29.4.2 XRD Pattern
		29.4.3 Structural Analysis Using FTIR
	29.5 Mechanism of Formation
	29.6 Optical Property
		29.6.1 Optical Absorption Spectrum
		29.6.2 Photoluminescence (PL)
	29.7 Electrical Property
	29.8 Conclusion
	References
30 Machine-Learning-Enhanced Polarization Splitter in Silicon-Integrated Dual-Core Photonic Crystal Fiber
	30.1 Introduction
	30.2 Material and Design
	30.3 Numerical Analysis
	30.4 Results and Discussions
		30.4.1 Optimization of PCF Design Parameters
		30.4.2 Features of the Proposed PCF
		30.4.3 Cross-Talk Performance of the Proposed PCF
	30.5 Implementing Machine Learning
		30.5.1 Program Code
	30.6 Conclusion
	References
31 Progress in Birefringent Material-Based Achromatic Phase Modulators
	31.1 Introduction
	31.2 Mathematical Aspects for Retarder Designing
		31.2.1 Conventional Approach
		31.2.2 Calculation of Plate Thickness
	31.3 Achromatic Phase Retarder Having Plates of the Same Birefringent Materials
		31.3.1 Superachromatic Phase Modulator with the Same Materials in the Visible Range
	31.4 Achromatic Phase Modulator with Different Birefringent Materials
		31.4.1 Superachromatic Phase Modulator Retarder Using More Than Two Birefringent Plates Covering Visible to SWIR Range
		31.4.2 Superachromatic Phase Modulator Using Different Materials in the SWIR Range
		31.4.3 Superachromatic Quarter-Wave Retarder Design with Optimum Thickness of Waveplates Using Flower Pollination Algorithm
		31.4.4 Proposed System with Different Birefringent Materials Behaving as Superachromatic Retarder in 800–2000 nm Wavelength Range
	31.5 Conclusion
	References
32 A Highly Stable Perfect Metamaterial Absorber Based on the Plasmonic Effect of Metamaterial Nano-cells for Optical Spectrum Applications
	32.1 Introduction
	32.2 Related Works
	32.3 Theoretical Aspects of Metamaterial Absorbers
	32.4 PMMA Design
		32.4.1 Proposed Configuration
		32.4.2 Simulation Arrangement
	32.5 Results and Discussion
		32.5.1 Frequency Spectra of the Proposed PMMA
		32.5.2 PMMA Adaptation
		32.5.3 Extraction of Effective Parameters
		32.5.4 Polarization Analysis
		32.5.5 Surface Current Distribution on PMMA
		32.5.6 Influence on Absorption Performance
		32.5.7 Equivalent Circuit Model
	32.6 Comparison with State of the Art
	32.7 Fabrication Possibilities
	32.8 Conclusions
	References
Part IV Recent Developments in Optical Wireless Communication Technology
33 Video Encryption Using Diffraction Grating and QR Code in Optical Frequency Domain
	33.1 Introduction
	33.2 Methodology
	33.3 Result
	33.4 Conclusion
	References
34 All-Optical Binary Decrementer Using Terahertz Optical Asymmetric Demultiplexer Switches
	34.1 Introduction
	34.2 Interferometric Optical Switch Utilizing TOAD Technology
	34.3 All-Optical Decrementer
	34.4 Circuit Performance Analysis and Discussion
	34.5 Conclusion
	References
35 Software Defined Optical Wireless Network with AI
	35.1 Introduction
	35.2 Software Defined Network (SDN)
		35.2.1 Infrastructure Layer
	35.3 Software Defined Optical Network (SDON)
	35.4 SDN Interfaces
		35.4.1 Northbound Interfaces (NBIs)/Application-Controller Plane Interfaces (A-CPI)
		35.4.2 Southbound Interfaces (SBIs)
		35.4.3 Overview of Optical Networking
	35.5 Artificial Intelligence (AI)
		35.5.1 Unsupervised Learning
		35.5.2 Reinforcement Learning (RL)
		35.5.3 AI Algorithms
	35.6 AI in SDN
		35.6.1 Supervised Deep Learning in SDN
		35.6.2 WOA in SDN
		35.6.3 Enabling Technologies in the Device Aspect
		35.6.4 AI Based Optical Network Traffic Prediction
	35.7 AI-Powered Resource Allocation in Optical Networks
		35.7.1 Supervised Learning for Resource Allocation Strategy
		35.7.2 Optical Network Routing Assignment
		35.7.3 Supervised Learning-Based Routing
		35.7.4 Intra-Domain Learning with LSTM
		35.7.5 Reinforcement Learning for Decision-Making
		35.7.6 Supervised Learning and Integer Linear Programming (ILP) for RWA
	35.8 AI Based Optical Network Failure Management
		35.8.1 Network Scale and Alarm Analysis
		35.8.2 Alarm Analysis
		35.8.3 Failure Localization
		35.8.4 Hybrid Failure Localization Method
		35.8.5 Data Visualization for Failure Localization
	35.9 Conclusion
	References
36 Enhancing Optical MIMO System Performance Through Optical Multiplexing and Amplification
	36.1 Introduction
	36.2 Optical Communication System
	36.3 Design of Optical Communication Systems
	36.4 Performance Analysis of a (3 × 3) MIMO System
		36.4.1 Long-Haul Optical Communication Chain
		36.4.2 Three Optical Communication Subchains
		36.4.3 Assessment of Optical Amplification in the Proposed System
	36.5 Conclusion
	References
37 Fostering Advanced Optical Wireless Communication: Approaches for Addressing 5G/6G, IoT, Industry 4.0, and WLANs
	37.1 Introduction
		37.1.1 Free-Space Optical Communication (FSO)
		37.1.2 Visible Light Communication (VLC)
		37.1.3 5G /6G Networks
		37.1.4 Internet of Things (IoT)
		37.1.5 Industry 4.0
		37.1.6 Wireless Local Area Networks (WLANs)
	37.2 Challenges in 5G /6G, IoT, Industry 4.0, and WLANs
		37.2.1 High Data Rates and Spectrum Efficiency
		37.2.2 Interference and Coexistence
		37.2.3 Security and Privacy
		37.2.4 Scalability
		37.2.5 Line of Sight and Obstacles
		37.2.6 Energy Efficiency
		37.2.7 Integration and Standardization
		37.2.8 Cost and Scalability
		37.2.9 Environmental Factors
	37.3 Free-Space Optical Communication (FSO)
		37.3.1 Key Features and Advantages of FSO
		37.3.2 Challenges and Considerations
		37.3.3 Applications of FSO
	37.4 Visible Light Communication (VLC)
		37.4.1 Key Features and Advantages of VLC
		37.4.2 Challenges and Considerations
		37.4.3 Applications of VLC
	37.5 FSO and VLC in 5G /6G Networks, the Internet of Things (IoT), Industry 4.0, and Wireless Local Area Networks (WLANs)
		37.5.1 FSO and VLC in 5G /6G Networks
		37.5.2 FSO and VLC in IoT
		37.5.3 FSO and VLC in Industry 4.0
		37.5.4 FSO and VLC in WLANs
		37.5.5 Hybrid Solutions
	37.6 Optical Wireless Solutions in 5G /6G Networks
		37.6.1 Li-Fi (Light Fidelity)
		37.6.2 Optical Wireless Backhaul
		37.6.3 Quantum Key Distribution (QKD)
		37.6.4 Terahertz (THz) Communications
		37.6.5 Network Synchronization
		37.6.6 Energy Efficiency
	37.7 Optical Wireless Solutions for IoT Deployments
		37.7.1 High Data Rates
		37.7.2 Low Latency
		37.7.3 Energy Efficiency
		37.7.4 Security
		37.7.5 Interference Immunity
		37.7.6 Indoor and Controlled Environments
		37.7.7 Healthcare and Sensitive Environments
		37.7.8 Smart Agriculture
		37.7.9 Environmental Monitoring
		37.7.10 Retail and Location-Based Services
	37.8 Industry 4.0: Revolutionizing Manufacturing with Optical Wireless Solutions
		37.8.1 High-Speed Data Transfer
		37.8.2 Low Latency
		37.8.3 Network Reliability
		37.8.4 Energy Efficiency
		37.8.5 Security
		37.8.6 Flexibility and Scalability
		37.8.7 Indoor Localization
		37.8.8 Maintenance and Predictive Analytics
		37.8.9 Quality Control
		37.8.10 Human–Machine Interaction
		37.8.11 Supply Chain Integration
	37.9 Optical-Based Solutions for WLANs
		37.9.1 Indoor Navigation and Positioning
		37.9.2 Smart Lighting Integration
		37.9.3 Low Interference and Secure Communication
		37.9.4 Healthcare and Sensitive Environments
		37.9.5 Energy Efficiency
		37.9.6 High-Density Environments
		37.9.7 Data Security in Critical Applications
		37.9.8 Underwater Communications
	37.10 Advanced Optical Communication Technologies
		37.10.1 Advanced Modulation Schemes
		37.10.2 Beamforming and Tracking
		37.10.3 Hybrid Solutions
		37.10.4 Quantum Key Distribution (QKD)
		37.10.5 Distributed Antenna Systems (DAS)
		37.10.6 Li-Fi (Light Fidelity)
		37.10.7 Miniaturization
		37.10.8 Terrestrial and Satellite Integration
	37.11 Conclusion and Future Work
	References