Broadband Wireless Communication Research Articles

Application of STBC in MIMO-OFDM Broadband Wireless Communications

The Space Time Block Coding (STBC) is applied in multiple transmit antennas using data transfer for fading channels. After being encoded, the data is broken into n streams of continuously broadcast strings over n transmit antennas using STBC. The received signal is the combination of n broadcast signals and it becomes erroneous due to the entry of noise at receiver end. The probabilistic decoding approach is applied instead of joint detection approach for recovering data via decoupling of signals delivered from various antennas. The maximum likelihood decoding scheme employs the orthogonal structure of STBC called as OSTBC (Orthogonal Space Time Block Code) for providing the maximum likelihood decoding algorithm depending upon linear computation at receiver. In the present work, a MATLAB/SIMULINK environment of OSTBC has been used in order to acquire the highest dimension of variability for specific number of broadcasts as well as receive antennas utilizing a simple decoding techniques. With or without Grey Coding, OSTBC / STBC is used in MATLAB / SIMULINK blocs. The OSTBC algorithm calculates the highest achievable transmission rate for every amount of transmit antennas in any constellations including M-PSK array. M-PSK STBCs are used for different complex constellations to achieve ½ as well as ¾ of highest allowable transmission rate for Multiple Input Multiple Output (MIMO) transmit antennas utilizing various constellations

A novel authentication scheme for long-term evolution mobility management: A security investigation

Long-term evolution in wireless broadband communication aims to provide secure communication for users and a high data rate for a fourth-generation network. Even though the fourth-generation network provides security, some loopholes lead to several attacks on the fourth-generation network attacks. The denial-of-service attack occurs when the user communicates with a rogue base station, and the radio base station in fourth-generation long-term evolution networks ensures that the user is attached to the rogue node assigned network. The location leak attack occurs when the packets are sniffed to find any user’s location using its temporary mobile subscriber identity. Prevention of rogue base station and location leak attacks helps the system achieve secure communication between the participating entities. Earlier works in long-term evolution mobility management do not address preventing attacks such as denial-of-service, rogue base stations and location leaks and suffer from computational costs while providing security features. Hence, the present paper addresses the vulnerability of these attacks. It also investigates how these attacks occur and exposes communication in the fourth-generation network. To mitigate these vulnerabilities, the paper proposes a novel authentication scheme. The proposed scheme is simulated using Network Simulator 3, and the security analysis of the proposed scheme is shown using AVISPA –a security tool. Numerical analysis demonstrates that the proposed scheme significantly reduces communication overhead and computational costs associated with the fourth-generation long-term evolution authentication mechanism.

Resource-Efficient Multicast URLLC Service in 5G Systems.

Many emerging applications, such as factory automation, electric power distribution, and intelligent transportation systems, require multicast Ultra-Reliable Low-Latency Communications (mURLLC). Since 3GPP Release 17, 5G systems natively support multicast functionality, including multicast Hybrid Automatic Repeat Request and various feedback schemes. Although these features can be promising for mURLLC, the specifications and existing studies fall short in offering guidance on their efficient usage. This paper presents the first comprehensive system-level evaluation of mURLLC, leveraging insights from 3GPP specifications. It points out (i) how mURLLC differs from traditional multicast broadband wireless communications, and (ii) which approaches to provide mURLLC require changing the paradigm compared with the existing solutions. Finally, the paper provides recommendations on how to satisfy strict mURLLC requirements efficiently, i.e., with low channel resource consumption, which increases the capacity of 5G systems for mURLLC. Simulation results show that proper configuration of multicast mechanisms and the corresponding algorithms for mURLLC traffic can reduce resource consumption up to three times compared to the baseline solutions proposed for broadband multicast traffic, which significantly increases the system capacity.

Reconfigurable Microwave Multi-Beamforming Based on Optical Switching and Distributing Network

Optical beamforming in microwave photonics is promising for supporting broadband wireless communications. However, the current optical beamforming lacks freedom because of the fixed connection between radio frequency (RF) signal and antenna elements (AEs). This manuscript tackles this challenge by proposing a dynamical optical beamforming architecture that reconfigures the antenna subarray for signal transmission depending on the number of signals to be transmitted. The proposed architecture employs an optical switching and distributing network (SDN) to realize a flexible connection between signals and AEs. An instance of the proposed architecture in photonic integrated circuits, which enables three working modes and transmits four RF signals through sixteen AEs, was presented and numerically simulated. The optical field distribution and beam pattern plots illustrated the operational principle and validated the feasibility of the proposed SDN architecture. Furthermore, the impact of the introduced architecture on the signal amplitude–phase consistency and the comparison of the proposed dynamic architecture and conventional fixe architectures are analyzed and discussed. The results indicate that the proposed architecture exhibits variable beamforming gain with lower hardware complexity.

Prospects for visible color for underwater wireless broadband communications

Prospects for visible color for underwater wireless broadband communications

Performance analysis of OFDM with variations in cyclic prefix and FFT lengths

Orthogonal Frequency Division Multiplexing (OFDM) is a modern and suitable modulation strategy for commercial high-speed broadband wireless communication systems. This is because wireless services and demands have grown so quickly in recent years. While creating wireless communication, the channel environment is crucial. A square grid with identical vertical and horizontal spacing is used for the constellation points in quadrature amplitude modulation (QAM). More bits can be transferred per symbol to higher-order modulation forms. This research has looked at how Orthogonal Frequency Division Multiplexing OFDM systems perform using different modulation techniques on channels with additive white Gaussian noise (AWGN). Using MATLAB software to do an experiment with different modulation methods and parameters such as FFT length and cyclic prefix findings showed that 64-QAM modulation sends the same amount of data faster and with fewer symbols than QPSK 16-QAM. Here, the 64-QAM modulation technique performs better. An extensive literature survey has been carried out. The work done here involved working on many parameters to improve the performance of OFDM, i.e., by reducing BER, changing modulation techniques, and analyzing the trade-off between cyclic prefix length and Bit Error Rate. Compared to the existing work, the proposed system provides better performance.

Transparent ultrawideband polarization-insensitive absorber with optimal thickness based on a grid ITO structure

With the large-scale commercialization of broadband wireless communication technologies, interference between spatial electromagnetic waves (EMWs) is becoming increasingly serious. As devices for solving electromagnetic interference (EMI) problems, microwave absorbers (MAs) have become increasingly mature with the rapid development of artificial electromagnetic structures. However, current MAs still face challenges in terms of wideband absorption, wide-angle absorption, thickness, etc., which limits their application scenarios. Therefore, this paper proposes a transparent ultrawideband polarization-insensitive absorber based on a grid indium tin oxide (ITO) structure. This design adopts a multilayer structure with a total thickness of 3.525 mm (0.114λ L ), close to the predicted minimum thickness, to expand the bandwidth. The grid-patterned ITO film resonant structure and ITO film ground plane are designed to further improve optical transmittance by increasing duty ratios. Simulation results demonstrate over 90% absorption from 9.7 GHz to 69.2 GHz, with a fractional bandwidth (FBW) of 150.8%. The absorber has good incident angle stability and polarization insensitivity. When the incident angle varies within 0-60°, the proposed absorber maintains an absorption close to 80% over an ultrawideband range, and the absorption remains nearly constant when the polarization angle changes from 0° to 90°. The fabricated sample shows a visible light transmittance of approximately 73.2%, and shows an absorption performance consistent with simulations in the 6-38 GHz frequency range, validating the effectiveness of the proposed design. Due to its transparent, ultrawideband absorption, wide incident angle stability and polarization insensitivity properties, this proposed absorber has important guiding significance for applications in high-frequency transparent electronics, radars, communications systems and other devices working in the microwave frequency band.

Public safety network design for broadband wireless access

Public protection and disaster relief (PPDR) agencies rely on wireless communications to respond in the event of emergencies. Public safety networks (PSNs) provide the wireless network used by emergency services. PSN is used to support push-to-talk services with some data transmission by employing land mobile radios. However, PPDR agencies are increasingly relying on additional information such as videos that require higher bandwidths. Therefore, many countries are transitioning or integrating their public safety networks with advanced broadband wireless communication systems such as fourth-generation (4G) long-term evolution (LTE) and planning to evolve to fifth-generation (5G) new radio (NR) in the future. The paper investigates infrastructure sharing mechanisms and deployment strategies in the transition of PSNs to a 4G LTE network, including a roadmap for cost analysis. Additionally, the paper examines LTE-based PSN deployment scenarios in various countries and engages in a discussion of the advantages and disadvantages of different sharing mechanisms and coexistence schemes. Finally, the challenges within the Public Safety Broadband Network (PSBN) are addressed and potential future research directions in this domain are deliberated.

Optimized Downlink Scheduling over LTE Network Based on Artificial Neural Network

Long-Term Evolution (LTE) technology is utilized efficiently for wireless broadband communication for mobile devices. It provides flexible bandwidth and frequency with high speed and peak data rates. Optimizing resource allocation is vital for improving the performance of the Long-Term Evolution (LTE) system and meeting the user’s quality of service (QoS) needs. The resource distribution in video streaming affects the LTE network performance, reducing network fairness and causing increased delay and lower data throughput. This study proposes a novel approach utilizing an artificial neural network (ANN) based on normalized radial basis function NN (RBFNN) and generalized regression NN (GRNN) techniques. The 3rd Generation Partnership Project (3GPP) is proposed to derive accurate and reliable data output using the LTE downlink scheduling algorithms. The performance of the proposed methods is compared based on their packet loss rate, throughput, delay, spectrum efficiency, and fairness factors. The results of the proposed algorithm significantly improve the efficiency of real-time streaming compared to the LTE-DL algorithms. These improvements are also shown in the form of lower computational complexity.

Deep Learning Towards Intrusion Detection System (IDS): Applications, Challenges and Opportunities

With the growth of numerous technological areas, including sensors, embedded computing, broadband Internet access, wireless communications, distributed services, automatic identification, and tracking, the potential for integrating smart objects into our daily activities through the Internet has increased. The Internet of Things (IoT) is the confluence of the Internet and intelligent objects that can converse and cooperate with one another. IoT is a brand-new example that unifies Cyberspace with actual physical objects from various areas, including, business processes, human health, home automation, and environmental monitoring. It intensifies the use of Internet-connected strategies in our regular lives, carrying with it several advantages as well as security challenges. Intrusion Detection Systems (IDS) have been a crucial device for the defence of systems and material schemes for more than 20 years. However, applying traditional IDS techniques was challenging due to the IoT’s inimitable features, like resource-constrained devices and particular protocol stacks and standards. As a result, this survey will focus on various Deep Learning (DL)-based intrusion detection techniques. This study makes use of 50 research papers that focused on different techniques, and a review of studies that used those techniques was given. This research enables categorizing the methods employed for intrusion detection in IoT based on Convolutional Neural Network (CNN)-based methods, Deep Neural Network (DNN)-based methods, Optimization-based methods, and so on. Moreover, the categorization of approaches, published year, the dataset used, tools used, and the performance metrics are measured for intrusion detection in IoT. On the basis of the software used for implementation, performance achievement, and other factors, a thorough analysis was conducted. The conclusion identifies the research gaps and issues in a way that makes it clear why should create an efficient method for enabling efficient enhancement.

Channel Estimation and Multipath Diversity Reception for RIS-Empowered Broadband Wireless Systems Based on Cyclic-Prefixed Single-Carrier Transmission

In this paper, a cyclic-prefixed single-carrier (CPSC) transmission scheme with phase shift keying (PSK) signaling is presented for broadband wireless communications systems empowered by a reconfigurable intelligent surface (RIS). In the proposed CPSC-RIS, the RIS is configured according to the transmitted PSK symbols such that different cyclically delayed versions of the incident signal are created by the RIS to achieve multipath diversity. A practical and efficient channel estimator is developed for CPSC-RIS and the mean square error of the channel estimation is expressed in closed-form. We analyze the bit error rate (BER) performance of CPSC-RIS over frequency-selective Nakagami- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i> fading channels. An upper bound on the BER is derived by assuming maximum-likelihood detection. Furthermore, by applying the concept of index modulation (IM), we propose an extension of CPSC-RIS, termed CPSC-RIS-IM, which enhances the spectral efficiency. In addition to conventional constellation information of PSK symbols, CPSC-RIS-IM uses the full permutations of cyclic delays caused by the RIS to carry information. A sub-optimal receiver is designed for CPSC-RIS-IM to aim at low computational complexity. Our simulation results in terms of BER corroborate the performance analysis and the superiority of CPSC-RIS(-IM) over the conventional CPSC without an RIS and orthogonal frequency division multiplexing with an RIS.

Large dynamic range terahertz phase modulator based on graphene-metal hybrid metasurface

Terahertz (THz) dynamic phase modulator is indispensable in THz wireless communications, high-resolution imaging and radar systems. However, up to now, it is difficult to achieve dynamic tunable phase shift of more than 150 degrees in single-layer transmission mode. In this work, we proposed a THz dynamic large phase modulator based on graphene-metal hybrid metasurface. The simulation results show that, when the Fermi level of graphene changes from 0 eV to 0.86 eV, the phase shift exceeds 176 degrees. By modifying the structural parameters, a phase shift of 170 degrees can be achieved in a bandwidth of 50 GHz. We investigated the physical mechanism of the dynamic phase modulator, and established the relationship between phase shift and Fermi level theoretically. This study paves a new way for realizing dynamic large phase modulation, which is very important for the THz broadband wireless communication, high-resolution imaging and radar system.

Low‐profile wideband four‐element MIMO array using Giuseppe Peano AMC surface with improved efficiency and isolation for WLAN systems

AbstractA low profile four‐element multiple‐input multiple‐output (MIMO) array of printed dipole antenna (PDA) backed by second iteration of Giuseppe Peano fractal artificial magnetic conductor (AMC) is introduced for broadband wireless communications. First, a suggested PDA with a pair of microstrip E‐shaped dipoles excited by an E‐shaped microstrip feedline is used to expand the bandwidth in the range of 5.47–6.92 GHz (S11 ≤ −10 dB). Then, the suggested 4 × 4 Giuseppe Peano fractal AMC reflector is loaded into the PDA to exhibit −10 dB measured impedance bandwidth from 4.21 to 7.06 GHz (50.61%) for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The proposed four‐element MIMO array loaded by 6 × 6 AMC reflector with diverse polarizations of elements introduces a low profile wideband structure. The measured results of four elements include the broad bandwidths from 4.3 to 7.05 GHz with enhanced gains (more than 8 dBi) and high efficiencies. The high isolations between the four elements with diverse polarizations are obtained larger than 26.5 dB and they reach 66 dB over the operating bandwidth for MIMO systems. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 51.33%, enhanced radiation efficiency up to 94%, and excellent impedance matching with uni‐directional radiation patterns.

3 bit terahertz coder based on a graphene composite metasurface

Terahertz (THz) frequency coders are indispensable components of broadband wireless communication systems of the future. However, the coding of THz wave at multiple frequencies is still a challenge. In this work, a 3 bit THz coder based on a graphene composite metasurface is proposed and simulated using a full-wave electromagnetic simulation software. The unit cell of the device consists of three graphene-embedded split-ring-resonators (SRRs), i.e., SRR1, SRR2, and SRR3. The device has three transmission peaks modulated by external voltages of V1, V2, and V3. The central frequency of the peak generated by SRR1 locates at 0.864 THz and its maximum modulation depth is 79.6%. The second peak generated by SRR2 locates at 1.161 THz and has a maximum modulation depth of 87%. The third peak at 1.541 THz is produced by SRR3 and has a maximum modulation depth of 85.3%. More importantly, the device can be used as a 3 bit coder, and the codes of 111, 110, 101, 011, 100, 010, 001, and 000 are successfully realized by controlling the voltages of V1, V2 and V3. The proposed device has potential applications in next-generation broadband wireless communications.

Sub-millimeter wave nanoantenna-a review

Electromagnetic waves that have a wavelength of less than one millimeter are referred to as sub millimeter waves. In sub millimeter wave-based devices and systems, antennas are critical components that are vital to their operation. Antennas are used in situations when a transition between a directed wave and a free-space wave is needed. Since, electromagnetic characteristics for receiving and transmission of the nano antenna are mutually invertible, the properties of nano antenna are analyzed in sub millimeter wave frequencies and this overcomes the limitations of conventional antenna design. They are very small in size, provide more efficiency, and do not cause health threat. This paper reviews the applications of nano antenna, which operates at sub-millimeter wave frequency, in the field of energy harvesting, space technology, IoT applications, 5G network, smart clothing, bio sensing, communication, etc? Also, the nano antenna fabricated by 3D printing technology is also reviewed. The world’s ever-increasing energy need necessitates the development of alternate energy sources. There is a lot of research and development going on right now to enhance photovoltaic systems so that they can be more efficient, but the constraint is that they can only collect energy from the visible area of the electromagnetic spectrum. As a result, a novel device known as a Nano antenna has been developed to convert heat energy taken from the infrared spectrum into electricity. In the not-too-distant future, it will have an impact on a wide range of fields, such as mobile communication (5G), radar detection, and higher order frequency applications. Space communication, broadband wireless communications, wireless optical communication, and mobile communication will also benefit from its implementation.

Terminal Access Method of Power Equipment Based on eSIM in WSN Environment

To ensure the integration of wireless sensor network and broadband wireless communication network, we establish a new generation of power IoTs information communication system for smart grid, and propose a distribution automation terminal solution based on eSIM card. An adaptive access algorithm based on multi logic eSIM priority, and a WSN based power acquisition system architecture, are also put forward. Then, according to the statistical analysis results of service arrival, the dialing and location information are integrated into one module. Through terminal classification and mobile modeling, a remote management mechanism based on EUICC is finally established. The system simulation test results show that the strategy adopted in this article can reduce the terminal access blocking rate in heterogeneous network environment, and the support of eSIM in WSN environment increases the integration of power equipment.

Research on Relay Network Method of Aerial Platform

As a regional wireless communication means, a wireless broadband communication system mainly provides communication services for mountainous areas with imperfect infrastructure construction. When the system provides communication services in mountainous areas, the vehicle-mounted base stations encounter obstacles to block communication, which causes the problem of non-cascade communication. In this paper, an improved genetic algorithm based on the adaptive change of crossover and mutation probability is proposed to formulate the air platform relay network planning scheme. The simulation results show that the crossover and mutation probabilities of the adaptive improved genetic algorithm change with the iteration of the algorithm, which improves the search ability of the algorithm and prevents it from falling into the local optimal solution.

Broad axial ratio bandwidth circularly polarized with wide angle coverage planar monopole antenna

A G-shaped circularly polarized broad axial ratio bandwidth (ARBW) and high gain monopole antenna is proposed. The proposed design is imprinted on low cost, lossy FR4 substrate with relative permittivity 4.4 and loss tangent 0.025. The physical dimension of the proposed antenna is 0.36λ0×0.39λ0×0.02λ0. The G-shaped patch is developed by modifying conventional monopole radiator to create circular polarization (CP) for strong horizontal and vertical current components. The stubs, L – shaped, and T-shaped parasitic strips (PSs) are loaded at the finest positions on the ground layer of the antenna to improve the performance of ARBW and gain. The achieved percentage impedance bandwidth (IBW), ARBW, angle coverage and gain are 106%, 97%, 102° (3 dB axial ratio beam width from −46° to + 56° in XZ – plane) at 4.26 GHz and 5 dBic respectively. The fabricated antenna is reliable for IEEE standard WLAN and broadband wireless communication system.

Broadband wireless communication with space-time-varying polarization-converting metasurface

Abstract Reconfigurable metasurfaces have emerged as a promising alternative to the conventional transmitter of wireless communication systems, due to their abilities of encoding digital information onto electromagnetic properties without complex radio-frequency chains. However, most of them are still limited to narrow operation bandwidth. Here, we propose a broadband metasurface-based wireless communication system that can actively adapt to multiple users located at versatile directions through joint modulation of digital signals in the time domain and wave scatterings in the space domain. As exemplary demonstrations, highly directive beams are generated to enhance regional signals in real-time customized for users in desired directions and reduce the signal leakage in undesired directions. Experiments are carried out to verify that the system can provide stable wireless communication service in a broad band of 3.7–5.1 GHz, within which the transmitted color picture enabled by the time-varying spatial modulation of metasurface can be successfully recovered at the user terminals. The proposed system may offer untapped potentials for next-generation communications and radar systems where regional signal enhancement, active adaption to users, and large channel capacities are required.

Terahertz phase modulator based on a metal-VO2 reconfigurable metasurface.

Actively controlling the phase of a terahertz (THz) wave is of great significance for beaming, tunable focusing, and holography. We present a THz phase modulator based on an electrically triggered vanadium dioxide (V O 2) reconfigurable metasurface. The unit cell of the device consists of two split-ring resonators embedded with a V O 2 ribbon. By electrically triggering the insulator-to-metal transition of V O 2, the resonance mode and resonance intensity of the unit cell can be dynamically controlled. The simulation results show that the structure can achieve a phase shift of about 360° in the range of 1.03-1.13THz, and the reflection amplitude can reach 80%. The device has potential applications in THz imaging, radar, broadband wireless communications, and array phase control.