Advanced Communication Systems Research Articles

Design and analysis of a microstrip antenna for superior 5G communication performance

The continuous advancement in communication systems is propelled by the growing demand for fifth-generation (5G) technology, aiming to meet the growing demands of systems that are small in size, operate at high speeds, and have a wide bandwidth. In order to address these requirements, innovative and highly efficient antenna configurations are of paramount importance. This article introduces a microstrip antenna that has been meticulously designed for optimal performance 5G systems. Optimized for 5G communication systems, the research focuses on the design and simulation of microstrip patch antennas which is shaped like butterfly, resonating at a frequency of 50.5 GHz. A Rogers RT5880 (lossy) substrate with a dielectric constant of 2.2 was employed in the antenna design. The dimensions of the proposed antennas were 6 × 6.5 × 0.787 mm³, which resulted in a geometric configuration resembling a butterfly. A comprehensive performance assessment involves exhaustive simulations using the CST Studio Suite application suite. In order to optimize critical parameters such as the Voltage Standing Wave Ratio (VSWR), reflected power, gain, frequency range (BW), and radiation pattern, the dimensions were meticulously adjusted. Significantly, the antenna operating at 50.5 GHz demonstrated a gain of 6.8 dB, in addition to a broad bandwidth of 5.364 GHz and an outstanding VSWR of 1.0131. The outcomes successfully underscore the outstanding performance exhibited by the butterfly-shaped design, thereby establishing its suitability for implementation in 5G networks.

Current Trends in Liquid Crystal Polymers and Their Applications: A Review

Liquid crystal polymers (LCPs) are now highly focused by researchers due to their improved thermal properties, mechanical strength, excellent dielectric strength, resistance to solvents, better dimensional stability, and gas barrier properties. LCPs can be used in valuable widespread applications such as energy storage, high-performance polymer fibers, actuators, information technologies, surface modification, shape memory materials, data storage, fiber optics, the medical field, electrical or electronics devices, aircraft, chemical, domestic equipment, ultra-high-strength fibers, biosensing, advanced communication systems, satellite systems, biosensing, bio-oscillators, and bioprocess monitoring. LCPs can self-assemble into different liquid crystalline phases like nematic, cholesteric, smectic, and columnar phases. The self-assembling structures of LCPs can be affected by the chemical and structural structures of the backbone of the polymeric material, nearby alkyl tails, mesogenic units, flexible spacers, etc. Depending on the mesogenic units in their molecular architecture, LCPs are basically classified into various categories, such as crosslinked, main chain, and sidechain. Again, they are also classified as cholesteric, nematic, and smectic mesophases. This paper provides a fundamental understanding, an informative overview, and details of structural aspects, properties, classification, commercial aspects, and applications of LCPs.

Next-Generation Dual Transceiver FSO Communication System for High-Speed Trains in Neom Smart City

Smart cities like Neom require efficient and reliable transportation systems to support their vision of sustainable and interconnected urban environments. High-speed trains (HSTs) play a crucial role in connecting different areas of the city and facilitating seamless mobility. However, to ensure uninterrupted communication along the rail lines, advanced communication systems are essential to expand the coverage range of each base station (BS) while reducing the handover frequency. This paper presents the dual transceiver free space optical (FSO) communication system as a solution to achieve these objectives in the operational environment of HSTs in Neom city. Our channel model incorporates log-normal (LN) and gamma–gamma (GG) distributions to represent channel impairments and atmospheric turbulence in the city. Furthermore, we integrated the siding loop model, providing valuable insights into the system in real-world scenarios. To assess the system’s performance, we formulated the received signal-to-noise ratio (SNR) of the network under assumed fading conditions. Additionally, we analyzed the system’s bit error rate (BER) analytically and through Monte Carlo simulation. A comparative analysis with reconfigurable intelligent surfaces (RIS) and relay-assisted FSO communications shows the superior coverage area and efficiency of the dual transceiver model. A significant reduction of up to 76% and 99% in the number of required BSs compared to RIS and relay, respectively, is observed. This reduction leads to fewer handovers and lower capital expenditure (CAPEX) costs.

V2V Communication in Smart Traffic Systems: Current status, challenges and future perspectives

Implementing V2V communication in intelligent traffic systems has been a topic of growing interest due to its potential to improve road safety and traffic flow. However, the widespread adoption of V2V communication in intelligent traffic systems could be enhanced by various challenges, such as infrastructure cost, security, and interoperability. These challenges must be addressed to improve the potential benefits of V2V communication. The problem statement of this study is to examine the potential benefits and challenges of V2V communication in intelligent traffic systems and provide insights into the current state of the art in V2V communication research. The proposed approach is to conduct a literature review of recent research on V2V communication in intelligent traffic systems to identify the potential benefits and challenges of V2V communication and the current state of the art in V2V communication research. The study aims to contribute to the field by comprehensively understanding the implementation of V2V communication in intelligent traffic systems and informing potential future research in this area. V2V communication can improve road safety and traffic flow in intelligent traffic systems. However, more research is needed to address the challenges and develop advanced and cost-effective V2V communication systems.

Coherent Chaotic Communication Using Generalized Runge–Kutta Method

Computer simulation of continuous chaotic systems is usually performed using numerical methods. The discretization may introduce new properties into finite-difference models compared to their continuous prototypes and can therefore lead to new types of dynamical behavior exhibited by discrete chaotic systems. It is known that one can control the dynamics of a discrete system using a special class of integration methods. One of the applications of such a phenomenon is chaos-based communication systems, which have recently attracted attention due to their high covertness and broadband transmission capability. Proper modulation of chaotic carrier signals is one of the key problems in chaos-based communication system design. It is challenging to modulate and demodulate a chaotic signal in the same way as a conventional signal due to its noise-like shape and broadband characteristics. Therefore, the development of new modulation–demodulation techniques is of great interest in the field. One possible approach here is to use adaptive numerical integration, which allows control of the properties of the finite-difference chaotic model. In this study, we describe a novel modulation technique for chaos-based communication systems based on generalized explicit second-order Runge–Kutta methods. We use a specially designed test bench to evaluate the efficiency of the proposed modulation method and compare it with state-of-the-art solutions. Experimental results show that the proposed modulation technique outperforms the conventional parametric modulation method in both coverage and noise immunity. The obtained results can be efficiently applied to the design of advanced chaos-based communication systems as well as being used to improve existing architectures.

Energy‐efficient hybrid beamforming for millimeter‐wave‐based massive multiple‐input multiple‐output system

SummaryThe advanced wireless communication system requires abridged energy consumption, enhanced data rate, and good signal coverage. The massive MIMO technology for 5G systems has been developed to accommodate several users simultaneously with superior throughput. The claim for high data rate wireless communication services is expanding quickly as time goes. Thus, the key difficulty is that as the number of users grows, the number of phase shifters grows as well, causing the system to consume more power; as a result, the system's energy efficiency decreases. Hybrid beamforming has recently emerged as an attractive technique for millimeter‐wave (mmWave) communication systems. The analog beamformer in the RF domain and digital beamformer in the baseband are coupled through a minimal number of RF chains in hybrid beamforming architecture. Hybrid beamforming utilizes fewer RF (radio frequency) chains than the total number of antennas to have a lower energy consumption design. The hybrid beamforming for a mmWave‐based massive MIMO system through different phase shifter selection mechanisms is proposed to achieve the highest energy efficiency for mmWave communications systems. The fully connected with phase shifter selection, sub‐connected with phase shifter selection (SPSS), and fully connected and sub‐connected with phase shifter selection with halved and doubled switches are considered for this research. The simulation results show the SPSS with halved switch outperforms on energy efficiency.

Effects of F− substitution on crystal structure, band characteristics and microwave dielectric properties of Li3Mg2NbO6 ceramics for high frequency applications

The structure–performance mechanism is essential to achieve comprehensive characteristics for advanced communication system. In the present work, F− ions were adopted to fabricated Li3Mg2NbO6-x/2Fx ceramics at a nitrogen atmosphere to modify dielectric characteristics. Correlation between bond characteristics, crystal structure and enhanced microwave dielectric characteristics was investigated through vibration analysis, P–V-L theory, Rietveld refinement, and First-principle calculations. Raman analysis and Rietveld refinement show that F− substitution led to a single phase. First-principle calculations indicates a high energy gap of 3.676 eV and p orbit contributed to Fermi energy. F− substitution led to the increase of Nb O bond ionicity and lattice energy, accounting for the variation in Q×f value and dielectric constant. The τf value was related to the expansion coefficient of the Li–O bond. Remarkably, the samples (x = 0.08) exhibited comprehensive dielectric characteristics with εr = 15.9, Q×f = 143,000 GHz and near-zero τf = −2.1 ppm/°C, proving an effective strategy for collaborative regulation. Based on structure simulation, 5G filter with ultra-low loss and high-suppression was designed through introducing transmission zeros from cross coupling. More specifically, a dielectric filter exhibited an interpolation loss of 0.2 dB at 3.3–3.6 GHz and high attenuations of 15 dB for 20 MHz outside the passband, verifying the feasibility for 5G applications.

Back-contact perovskite light-emitting diodes

Light-emitting diodes utilizing halide perovskites have experienced rapid advancements in recent years, demonstrating notable external quantum efficiencies. Despite these strides, the practical implementation of such devices remains constrained. In this contribution, we are dedicated to developing perovskite light-emitting diodes with a back-contact architecture using the MAPbBr3 active layer and SnO2 and Ni/NiOx back electrodes. The quantum efficiency of the fabricated devices stands at 0.015%. The operational voltage of the light-emitting diodes is characterized by its pronounced low values, attaining a maximum luminance of 70 cd/m2 at a mere 3.2 V. These results demonstrate the considerable promise of the developed back-contact perovskite light-emitting diodes for prospective applications in advanced display technologies and light communication systems.

Synthesis of CoFe2O4/mesoporous-carbon hybrid nanocomposite with enhanced microwave absorption in K and Ka-band

In the present investigation, CoFe2O4/mesoporous-carbon nanocomposites were synthesized using a facile hydrothermal method and demonstrate their dual band (K and Ka-band) microwave absorption properties, where radiation from high-resolution and close-range radars, space telescopes, and wireless point-to-point microwave communication systems populates. XRD results confirmed the pure phase formation of CoFe2O4 nanoparticles. Vibrating sample magnetometer shows a decrease in magnetization value for CoFe2O4/mesoporous-carbon nanocomposites that can be attributed to the increasing contents of non-magnetic mesoporous carbon. The reflection loss of the hybrid nanocomposite reached −31 dB at a matching thickness of 2.5 mm and effective absorption bandwidth was 4.4 GHz. The enhanced microwave absorption properties derive from the synergistic effect amid dielectric and magnetic loss of mesoporous-carbon and ferrite, respectively, and better impendence matching at their interface. In addition, the dielectric loss can be associated with polarization relaxation and mesoporous carbon conductivity and the magnetic loss arises from the natural resonance of ferrite materials. The high reflection loss and wide absorption bandwidth display that CoFe2O4/mesoporous-carbon nanocomposite having admirable microwave absorption performances can be a capable candidate for stealth technology and in advanced communication systems.

Some Properties of a Discrete Lorenz System Obtained by Variable Midpoint Method and Its Application to Chaotic Signal Modulation

Various discretization effects caused by applying numerical integration techniques to continuous chaotic systems are broadly studied in nonlinear science. Along with the negative impact on the precision of the various finite-difference schemes, such effects may have surprisingly fruitful practical applications, e.g. pseudo-random number generation, image encryption with improved diffusion and confusion properties, chaotic path planning, and many others. One such application is chaos-based communication systems which gained attention in recent decades due to their high covertness and broadband transmission capability. A crucial problem in the design of chaotic communication systems is the modulation of carrier signals. Due to the noise-like properties of chaotic signals, they can barely be modulated using the same methods as conventional harmonic signals. Thus, developing new modulation techniques is of great interest in the field of chaotic communications. In this study, we investigate the discrete model of the Lorenz oscillator obtained using controllable midpoint numerical integration and develop a novel modulation technique for chaos-based communication systems. We discover and analyze the multistability phenomenon in the dynamics of the investigated finite-difference Lorenz model through bifurcation, the basin of attraction, and Lyapunov spectrum analysis procedures. Using a specially designed testbench, we explicitly show that the proposed modulation method outperforms commonly used parametric modulation and is nearly equal to the state-of-the-art symmetry-based modulation in terms of covertness and noise resistivity. In addition, the proposed modulation technique is much easier to implement using computer arithmetics, especially in fixed-point hardware. The reported results may be efficiently applied to designing advanced chaos-based communications systems or improving the characteristics of existing communication system architectures.

Enhancing Sustainability through the Development of Port Communication Systems: A Case Study of the Port of Koper

This paper addresses the highly topical issue of the digitalisation of the port community through the development of advanced port communication systems (PCSs). The efficient and sustainable operation of container terminals (CTs) plays a key role in global trade and in ensuring the sustainable functioning of transport chains. While larger container terminals utilise PCSs, smaller container terminals often face challenges when implementing similar systems due to resource constraints and unique operational characteristics. This research analyses the impact of PCSs on the operational processes and information exchange between the smaller CT in the Port of Koper and the local port community. The aim of this study is to identify the possibilities of upgrading PCSs with modern information technologies, such as artificial intelligence (AI), blockchains, internet-of-things (IoT), etc., that will lead to more efficient execution of operational processes, reduced congestion and a lower carbon footprint for the port community as a whole. The paper provides guidelines for the possible coordinated development of PCSs in the Northern Adriatic to ensure the most harmonised operation of stakeholders in different ports or CTs.

Communication Systems: an Overview of Past, Present and Futuristic Outlook

In contemporary times, communication systems have become the major drivers of globalization and trade facilitation. From its simple beginning to the more recent 5G and 6G technologies which are at various stages of development and applications, capable of entrenching the era of the Internet of Things (IoT), advancing Machine-to Machine (M-2-M) integration, and further revolutionizing the speed of seamless communication between smart devices. Significant advancements have also been achieved in the area of auxiliary technology interfaces incorporated into mobile communication systems such as the wireless LAN (Wi-Fi), Bluetooth, Infra-Red (IR), and sundry communication systems operating at the higher frequency bands of the electromagnetic spectrum. Against this backdrop, this work reviewed some communication systems highlighting their technology and developmental trends. Furthermore, it attempts to accurately forecast the probable direction of future advancements in communication systems, based on a painstaking trend and pattern analysis of the technological improvements of Bluetooth, Radar, and Wi-Fi technologies and some other communication systems in the past decade.

Design and Optimization of E-Band Fluor tellurate Fiber Amplifier Doped with Praseodymium

This study focuses on investigating and selecting an appropriate optical fiber material, specifically emphasizing the utilization of fluorotellurate as the base material. The objective is to enhance the performance of the optical fiber material by incorporating praseodymium ions, which possess unique properties advantageous for optical amplification.To gain an accurate understanding of the working principle of the fiber optic amplifier, a mathematical model is developed. This model acts as a valuable tool for simulating and optimizing the amplifier's performance. By conducting rigorous simulations and optimization processes using this model, critical parameters can be identified and fine-tuned to achieve optimal gain characteristics.To verify the efficacy of the designed fiber amplifier, comprehensive experimental tests are conducted. The results from these experiments convincingly demonstrate the amplifier's remarkable gain characteristics, particularly within the E-band frequency range. This research breakthrough not only highlights the amplification capabilities of the designed fiber amplifier but also presents a promising design scheme for future E-band communication systems. By selecting fluorotellurate as the base material and incorporating praseodymium ions, this study introduces an innovative approach to enhance the performance of optical fiber amplifiers. The development of a robust mathematical model enables efficient simulation and optimization, thus acting as a valuable tool for the future design and development of amplifiers. The successful experimental validation further emphasizes the potential of the designed fiber amplifier as a pivotal component for advanced E-band communication systems.

Performance enhancement of Graphene-Based elliptical patch antenna for THz applications

The advancement of wireless communication applications has proliferated in recent years. The antenna design is crucial in evaluating the effectiveness of most of these wireless communication applications that demand extensive bandwidth and a lofty data rate. THz (Terahertz) band is becoming a key factor for advanced wireless communication applications. The design of microstrip patch antennas in the THz band is preferred as one of the most significant for advanced wireless applications. This paper proposed an elliptical patch antenna with a T-shape slot on the patch and partial ground methods to meet the speed demand of advanced wireless communication systems. The overall size of the antenna is 160 × 120 µm2. We investigated the antenna performance by using computer simulation technology (CST) simulation software. The simulation results indicate that our proposed antenna improves the bandwidth by 0.72 THz (720 GHz) with a return loss suppression of 12 dB. Moreover, the gain and efficiency of the proposed antenna show satisfactory enhancement. Based on the concept of a T-shape slot on the patch and partial ground method, we confirm the performance improvement of the proposed antenna through simulation results.

Wide-angle beam scanning from binary amplitude-modulated conformal meta-surface dense array with precise beam granularity

We propose a binary amplitude-modulated conformal meta-surface with every meta-element capable of functioning as the leaky wave passage or the null radiating spot through dynamically tuning the PIN diodes over the meta-elements with ON or OFF states. In particular, the staggered arrangement of the meta-elements forms a dense radiating array with 0.1 wavelength periodicity and every radiating patch consists of dual hourglass shaped slots stacked over the coupled feed of substrate integrated waveguide slits. Such a design, on the basis of binary amplitude-modulated conformal meta-surface frames, can achieve wide-angle steerable fan-beam scanning, while possessing the precise beam direction with less than one tenth of the 3 dB beamwidth. Thus, this should pave the way for building up more advanced contemporary conformal wireless communication systems over different platforms.

Spatial–Temporal Federated Transfer Learning with multi-sensor data fusion for cooperative positioning

With the development of advanced embedded and communication systems, location information has become a crucial factor in supporting context-aware or location-aware intelligent services. Among these services, modern Intelligent Transportation System (ITS) has the strictest requirements for real-time, accurate, and private location data. In this study, a Spatial-Temporal Federated Transfer Learning (ST-FTL) framework is designed and introduced to achieve more precise cooperative positioning with multi-sensor data fusion while protecting the location data privacy in urban ITS. Specifically, a three-layer FTL architecture is constructed to enhance the prediction accuracy on GPS positioning errors for vehicles in different regions especially when facing missing local data in some specific scenarios (e.g., urban canyons), in which Transfer Learning (TL) is incorporated to optimize the initialization of global model with faster convergence but less communication cost in Federated Learning (FL). A multi-attribute based spatial-temporal clustering algorithm is developed to facilitate the finding of more appropriate source domains similar to the target domain in a density-based scheme, while a convolutional-gated unit is newly designed to further filter out the useless features and add new features based on the convolution operations and gating mechanism, resulting in more effective global model initialization and weight aggregation from cross-region selection. A multi-sensor data fusion model is built in local to improve the prediction accuracy on positioning errors, in which an improved time-aware asymmetric attention mechanism is involved to selectively adjust the weight importance of the incorporated GPS and Inertial Measurement Unit (IMU) data in a more targeted fusion process. Additionally, an improved Siamese network structure, which breaks the traditional dual network structure and only adopts one single network structure, is leveraged to realize the lightweight data augmentation based on the better utilization of historical similar data from local vehicles themselves, when suffering from insufficient training data. Experiments and evaluations based on two different public datasets demonstrate the outstanding performance of our proposed model and method in achieving superior prediction accuracy and faster convergence for cooperative positioning compared with other state-of-the-art positioning methods in urban ITS.

Applied Nonlinear Analysis for Efficient Communication Signal Processing and Network Management

The use of nonlinear analysis in network management and communication signal processing is a revolutionary strategy that is redefining contemporary networking paradigms. The goal of this project is to improve communication systems' resilience, efficiency, and agility by integrating cutting-edge nonlinear techniques. This study investigates the complex relationship between signal processing and network management using nonlinear analysis techniques in order to meet the growing needs of modern networks. Nonlinear approaches provide dynamic signal processing methods, enabling in-the-moment modifications that maximise data transfer under variable network circumstances. Prioritising data streams is made easier by this integration, which also improves network speed and efficiently allocates resources to guarantee Quality of Service (QoS). The study explores the complexities of interdisciplinary ideas, using the concepts of nonlinear analysis to comprehend phase transitions, emergent network architectures, and networks' inherent ability to self-organize. By deciphering the complexity of network behaviours and their evolution, this understanding aids in the creation of more effective management techniques. However, there are difficulties with computing complexity, interoperability, and skill adaption when using nonlinear analysis in network management. To properly utilise nonlinear approaches for network management and communication signal processing optimisation, these obstacles must be overcome. The research is important because it may lead to game-changing advancements in communication systems by introducing cutting-edge ways that go beyond the constraints of conventional, linear methods. The findings show potential for more effective and secure communication systems, which can meet the increasing needs of modern networking.

Estimating Optimal Synchronization Parameters for Coherent Chaotic Communication Systems in Noisy Conditions

It is known, that coherent chaotic communication systems are more vulnerable to noise in the transmission channel than conventional communications. Among the methods of noise impact reduction, such as extended symbol length and various digital filtering algorithms, the optimization of the synchronization coefficient may appear as a very efficient and simple straightforward approach. However, finding the optimal coefficient for the synchronization of two chaotic oscillators is a challenging task due to the high sensitivity of chaos to any disturbances. In this paper, we propose an algorithm for finding the optimal synchronization parameter K_opt for a coherent chaos-based communication system affected by various noises with different signal-to-noise ratios (SNR). It is shown, that under certain conditions, optimal $K$ provides the lowest possible bit error rate (BER) during the transmission. In addition, we show that various metrics applied to the message demodulation task propose different noise immunity to the overall system. For the experimental part of the study, we simulated and physically prototyped two chaotic communication systems based on well-known Rossler and Lorenz chaotic oscillators. The microcontroller-based prototype of a chaotic communication system was developed to investigate the influence of noise in the real transmission channel. The experimental results obtained using the designed hardware testbench are in good correspondence with the theoretical propositions of the study and simulation results. The suggested evaluation metrics and optimization algorithms can be used in the design of advanced chaos-based communication systems with increased performance.

Design and analysis the performance of triangular patch antenna for THz applications

Modern technology advancement requires a more extensive data rate to convey information more rapidly than ever. Improved bandwidth can satisfy the need for high-speed transmission demand. In order to achieve significantly increased bandwidth for a high data rate communication, the antenna design at the THz band is essential. The microstrip patch antenna is one of the most prominent antennas for THz band applications such future 5G communication systems and advanced wireless communication system. This paper proposed a triangular patch antenna for THz applications where FR4 is used at the substrate as an insulator and Graphene at the patch as a conductor. Moreover, we improve the performance of the proposed antenna by modifying the shape of the patch and ground (GND) layer. We modify the patch shape by cutting the corner edge of the triangular patch. Moreover, the GND layer is modified with horizontally partial ground. The size of the proposed antenna is set to 160×120 µm2. We analyze the performance of the proposed antenna using CST simulation software. Based on the simulation results, the proposed antenna with a modified patch and GND shape shows wide bandwidth of 1.27 THz and minimal return loss of -33.22 dB at a resonant frequency of 2.28 THz. Additionally, the gain and efficiency of the suggested antenna show good improvement. Therefore, the proposed triangular patch antenna with a modified patch and GND shape is expected to be suitable for high-speed THz applications.

Iterative channel estimation and data detection algorithm for MIMO-OTFS systems

Channel estimation in high-mobility environments is a challenging problem for advanced mobile communication systems (5G and beyond). In this manuscript, we first propose an iterative algorithm for channel estimation and data detection in the delay-Doppler domain for multiple-input multiple-output orthogonal time frequency space system. Then, in order to increase the spectral efficiency of the system, we use a superimposed pilot pattern. The proposed algorithm takes advantage from the sparse nature of the channel in the delay-Doppler domain and iterates between message passing-aided data detection and data-aided channel estimation. For channel estimation, we propose two algorithms. The first one consists in estimating all channel parameters, including the number of path gains, delay taps, Doppler taps, and channel gains by using a mean-field approximation and the variational Bayesian expectation maximization algorithm. The second one, based on the fact that delay and Doppler taps remain unchanged for a rather long period of time, uses an MMSE approach combined with Cholesky decomposition to only estimate channel gains in each transmitted frame. For data detection, we adapt the message-passing algorithm proposed in the literature. We also derive a lower bound on the signal-to-interference-plus-noise ratio of the proposed scheme, and maximize it by optimally allocating power between pilots and data symbols. Finally, we compare the complexity and the performance in terms of normalized mean square error, bit error rate, and spectral efficiency against existing methods. Simulation results, conducted in high-mobility scenarios show that the proposed algorithm achieves a good compromise between complexity and performance.