Wireless Systems Research Articles

Deep Learning Models For Symbol Detection in UFMC Systems

The limited availability of the frequency band in wireless communication systems is one of the major obstacles to achieving high-speed data transmission. To overcome this obstacle, multicarrier systems, which utilize the available frequency bandwidth most efficiently to ensure spectral efficiency and consequently high data rate transmission, are used. In the Universal Filtered Multi-Carrier (UFMC) technique, which is one of the multi-carrier systems, in addition to high-speed data transmission, the bandwidth is divided into many sub-bands and only the lower sidebands are filtered, and as a result, the inter-channel interference problem is minimized. However, in UFMC systems, the error-free reception of symbols at the receiver is directly dependent on the performance of the symbol detection algorithm. In this study, symbol detection was performed in UFMC systems by taking advantage of the learning ability of deep learning methods, providing flexible solutions in solving nonlinear problems, reducing the hardware load by using fewer parameters and the ability to perform parallel processing, and thus the symbol detection performance of the system under bad channel conditions was increased.

Non-contact measurement of torque in rotational truck flywheel using resistance strain gauges based on wireless telemetry system

Non-contact measurement of torque in rotational truck flywheel using resistance strain gauges based on wireless telemetry system

Smart Home

The concept of a smart home integrates wireless electronic systems that connect household devices to a central interface, enabling remote control via smartphones or wall panels through Wi-Fi networks. This paper explores the core components of smart homes, including smart devices such as speakers, thermostats, lighting, and security systems, as well as the role of mobile applications in managing these devices. The paper discusses the various applications of smart homes, from home automation and security monitoring to energy management and health-focused initiatives. Additionally, it evaluates the pros and cons of smart home technology, highlighting benefits such as enhanced security, energy efficiency, and user convenience, while also addressing challenges related to cost, complexity, and cybersecurity risks. The paper concludes by emphasizing the transformative potential of smart homes in modern living, while recognizing the need for strategic approaches to mitigate associated challenges.

A Novel 5G Multi-mode Resonator and Filter with Symmetric Transmission Zeros

5G construction is becoming increasingly important. This paper introduces the theoretical basis of multi-mode filter, and on the basis of theoretical calculation and analysis, a novel 5G cavity multi-mode resonator and filter is designed by using ads/HFSS simulation software. The electric field characteristic of resonator is analyzed, and the mutual coupling between modes is realized by the way of screw perturbation. The electric field distributions of the mode is changed by adding tuning screws, two coupled degenerate modes act as two coupled resonators, so that the numbers of resonator can be reduced while keeping the resonance loop unchanged. For example, the characteristics of 3N section filter can be realized in the physical space of a traditional n-section filter by using three modes of a resonator, thus greatly reducing the volume of the filter. The results show that in the pass-band (3.5 GHz ~ 3.6 GHz): return loss > 17.9 dB, standing wave ratio < 1.29, insertion loss < 0.31 dB, a transmission zero point is introduced at 4 GHz on the right side of the pass-band, which makes the right side out of band attenuation rapidly. The filter has the advantages of small insertion loss, small size and good rejection of out of band, which can be applied to 5G band wireless communication system for better reliability.

IoT-Based Wireless System for Gait Kinetics Monitoring in Multi-Device Therapeutic Interventions.

This study presents an IoT-based gait analysis system employing insole pressure sensors to assess gait kinetics. The system integrates piezoresistive sensors within a left foot insole, with data acquisition managed using an ESP32 board that communicates via Wi-Fi through an MQTT IoT framework. In this initial protocol study, we conducted a comparative analysis using the Zeno system, supported by PKMAS as the gold standard, to explore the correlation and agreement of data obtained from the insole system. Four volunteers (two males and two females, aged 24-28, without gait disorders) participated by walking along a 10 m Zeno system path, equipped with pressure sensors, while wearing the insole system. Vertical ground reaction force (vGRF) data were collected over four gait cycles. The preliminary results indicated a strong positive correlation (r = 0.87) between the insole and the reference system measurements. A Bland-Altman analysis further demonstrated a mean difference of approximately (0.011) between the two systems, suggesting a minimal yet significant bias. These findings suggest that piezoresistive sensors may offer a promising and cost-effective solution for gait disorder assessment and monitoring. However, operational factors such as high temperatures and sensor placement within the footwear can introduce noise or unwanted signal activation. The communication framework proved functional and reliable during this protocol, with plans for future expansion to multi-device applications. It is important to note that additional validation studies with larger sample sizes are required to confirm the system's reliability and robustness for clinical and research applications.

Transmission Diversity by Alamouti-Coding, Propagation Control by IRS in CDMA-FBMC-OQAM System

This manuscript suggests a modulation scheme for exploiting transmission diversity by integrating Alamouti coding and controlling the transmission by intelligent reflecting surface (IRS) in code division multiple access filter bank multicarrier offset quadrature amplitude modulation (CDMA-FBMC-OQAM) system, a promising technique for future-generation wireless communication. To neutralize the impact of channel phases, the IRS elements are in charge of intelligently adjusting the incident signal phases. By maximizing the signal-to-noise-ratio (SNR) of the received signal, the bit-error-rate (BER) performance is improved. By changing the number of IRS elements, taking into account various channel scenarios and modulation schemes, we compare the BER performance of the proposed system with that of the conventional Alamouti coded CDMA-FBMC-OQAM system in simulation results. The findings demonstrate that the IRS-assisted Alamouti coded CDMA-FBMC-OQAM transmission is a feasible choice for future-generation wireless communication systems.

Feasibility Testing of the Bionet Sonar Ultrasound Transcutaneous Energy Transmission (UTET) System for Wireless Power and Communication of a LVAD.

To address the clinical need for totally implantable mechanical circulatory support devices, Bionet Sonar is developing a novel Ultrasonic Transcutaneous Energy Transmission (UTET) system that is designed to eliminate external power and/or data communication drivelines. UTET systems were designed, fabricated, and pre-clinically tested using a non-clinical HeartWare HVAD in static and dynamic mock flow loop and acute animal models over a range of pump speeds (1800, 2400, 3000 RPM) and tissue analogue thicknesses (5, 10, 15mm). The prototypes demonstrated feasibility as evidenced by meeting/exceeding function, operation, and performance metrics with no system failures, including achieving receiver (harvested) power exceeding HVAD power requirements and data communication rates of 10kB/s and pump speed control (> 95% sensitivity and specificity) for all experimental test conditions, and within healthy tissue temperature range with no acute tissue damage. During early-stage development and testing, engineering challenges for UTET size reduction and stable and safe operation were identified, with solutions and plans to address the limitations in future design iterations also presented.

ADVANCED SMART PARKING BARRIERS: DESIGN, IMPLEMENTATION, AND IMPACT ON URBAN INFRASTRUCTURE

This study investigates the creation and execution of an intelligent individual parking barrier system aimed at resolving urban parking difficulties in Malaysia. The project adheres to a systematic methodology that includes conceptual design, detailed design, prototype creation, testing and validation, data analysis and refinement, and implementation and deployment. The system's lifetime and efficacy are guaranteed by the inventive use of durable materials and advanced sensor technologies. Additionally, convenience and security are enhanced by a user-friendly wireless control system. The data analysis confirms that the system is highly reliable, with sensors that have a 95% success rate in detecting events and low delay in wireless control operation. The concept is in line with larger smart city projects, such as the Kuala Lumpur Smart City Blueprint, which aims to promote parking options that are both efficient and secure. In addition, the system promotes environmental sustainability by minimizing emissions related to the search for parking. It also aligns with the United Nations Sustainable Development Goals, namely SDG 11 (Sustainable Cities and Communities) and SDG 13 (Climate Action). This study showcases the possibility of implementing the proposed system on a large scale in different urban areas in Malaysia, therefore leading to the development of more intelligent and effective urban infrastructure.

Implementation of a Highly Mobile UAVs Direction Finding Complex Using Virtual Magnetic Dipoles

Relevance. In the context of the development of modern broadband communication systems, the task of performing direction finding of signals using highly mobile direction finding systems (UAVs) is becoming especially urgent. They impose restrictions on the size of antenna elements and the distance between them, which leads to an increase in the mathematical error of the bearing. Problem statement. The paper sets the task of considering the possibility of increasing the direction finding accuracy of a highly mobile complex by using virtual magnetic dipole technology. A feature of this method is the minimization of distortions introduced by the carrier body into the characteristics of the measured field. To measure the field characteristics, as well as their partial components, vector antenna elements were used. Goal of the work is to study the characteristics of a radio direction finding complex using virtual magnetic dipole methods in conditions of distortions introduced by the carrier body. As an example, cases of direction finding of differently polarized waves, taking into account the influence of radomes of antenna elements, assessment of the maximum resolution accuracy, as well as noise stability are considered. The finite element method implemented in DS CST Studio Suite 2024 was used in the modeling. Result. During the research, a plane wave with different bearings fell on a UAV with a direction finding complex, which made it possible to carry out the most accurate research. The results of the work also include the creation of a model of a radio direction finding complex, which can be installed on a small UAV, providing high accuracy of wave direction finding in passive mode.The novelty of the method used lies in the application of methods for the formation of virtual magnetic dipoles based on the measured characteristics of the distorted electric field. New to this work are modeling cases that are associated with noise suppression, the influence of antenna element housings, as well as assessment of the maximum resolution accuracy.Practical significance of the work lies in the creation of a model of a radio location system based on vector antenna elements, which are used to measure the characteristics of the electromagnetic field with subsequent direction finding based on the magnetic field.

A set of Models for Device Positioning in Sixth Generation Networks. Part 1. Methods Survey and Problem Statement

Relevance. Today, terahertz radio systems are considered as a technological basis for integrating methods and means of radio communication and radar in promising sixth-generation networks. If in 4G LTE networks the capabilities of positioning user equipment using the infrastructure of base stations were considered as auxiliary options, then in 5G NR networks, location determination technologies (LDTs) have become full-fledged services, the requirements for which are specified along with communication services. A new trend in positioning in 5G NR networks, compared to 4G LTE networks, has become a single-position assessment of the coordinates and orientation of the user equipment based on signals from a single base station with the ability to distinguish between direct and reflected signals. 6G networks are still in their infancy, but it can already be stated that they mark the next stage in the evolution of digital ecosystems, which is characterized by the convergence of communication technologies, localization and sensing of radio air and the surrounding space by radio engineering means.Purpose. This work opens a research cycle devoted to the review of models, methods and algorithms for positioning devices in 6G networks. The goal of the cycle is to find and justify new radio engineering means for achieving decimeter accuracy in 6G device coordinate estimates. The first part of the cycle provides an overview of the methods and formalization of the model for collecting primary measurements.Method is an analytical review of the state of the problem based on current scientific publications, conceptual modeling, categorical approach, expert combination, comparative analysis, formalization, mathematical and simulation modeling.Results. As a result of the review of device positioning methods during the transition to 6G networks, key performance indicators and LDT scenarios are updated. As a result of the comparative analysis of 5G and 6G networks, new factors, advantages and disadvantages of positioning technologies during the transition from millimeter wave networks to terahertz networks are systematized. A formalized mathematical model for collecting primary measurements is used in the simulation model for assessing the accuracy of device positioning in the second part of the cycle.Novelty. This cycle is the first such study in the Russian scientific segment on network positioning of the sixth generation of the terahertz range, in which the author's version provides an overview of methods and a systematization of a set of new factors of the OMP in communication networks.The theoretical significance of the review-analysis lies in the establishment of both technological obstacles and new opportunities for increasing positioning accuracy during the transition to 6G networks.The practical significance of the formalized mathematical model lies in its subsequent software implementation for numerical justification of the limits of positioning accuracy in 6G networks.

Data-driven design of a derailment detection system for freight wagons

Railway transportation is widely known for its high safety level. Nevertheless, derailments still occur, typically causing large service disruptions and economic losses. For these reasons, identifying derailments is of paramount importance for improving the railway transportation safety. This paper presents the design and testing of a derailment detection system for freight trains. A derailment detection algorithm able to process and analyze data in real-time has been designed leveraging the knowledge gained from full-scale derailment tests on freight wagons. Moreover, a LoRa-based wireless communication system has been implemented to relay freight wagon derailment warnings to the locomotive. The effectiveness of the proposed derailment detection algorithm is proved through its deployment to a freight wagon used for common operations. In that, it demonstrated increased robustness against derailment false triggering compared to traditional mechanic-pneumatic detectors. Furthermore, the proposed wagon-locomotive wireless communication system is proven effective in transmitting information across various convoy compositions and freight wagon loading conditions during operational testing on the railway line.

Photonics-aided exceeding 200-Gb/s wireless data transmission over outdoor long-range 2 × 2 MIMO THz links at 300 GHz

Outdoor long-range terahertz (THz) communications often come at the expense of transmission rate. Moreover, the practicability of the single polarization optical/THz link, which is commonly used in the previous long-range THz demonstrations based on photonics, is extremely limited by the following two fatal defects. One is relying on active polarization control, and the other is not supporting the transparent bridging of optical polarization division multiplexed (PDM) signals for mature coherent optical communication networks. In this work, a large-capacity photonics-aided THz wireless communication system based on the outdoor long-range 2 × 2 multiple-input multiple-output (MIMO) links has been successfully demonstrated. We first build the 200-m 2 × 2 MIMO THz wireless links at the 300 GHz band. The cascaded linear and nonlinear equalizers are proposed which can significantly improve the transmission performance of 100- and 200-Gb/s PDM quadrature phase shift keying (QPSK) signals. Then an interesting 2 × 2 MIMO structure which can provide certain diversity reception gain under 200-m long-range wireless delivery using the same polarization scheme is also presented and further compared with the orthogonal polarization scheme. Since each THz receiver simultaneously receives data from both the two THz transmitters for this MIMO links, an improvement over 6 dB in receiving sensitivity and one order of magnitude in bit error ratio performance under low signal-to-noise ratio conditions can be achieved. Finally, based on the proposed cascaded equalizers and novel 2 × 2 MIMO structure, we successfully demonstrate a record-breaking 58-Gbaud (232-Gb/s) PDM-QPSK signal transmission over 200-m 2 × 2 MIMO THz wireless links. This is an important attempt for the photonics-aided THz wireless communication systems to achieve 2 × 2 MIMO transmission over a long wireless distance in the outdoors. Furthermore, attaining over 200 Gb/s at a wireless distance of 200 m also represents a key milestone for the long-range and large-capacity THz wireless communication systems.

A Microwave Photonic Channelized Receiver Based on Polarization-Division Multiplexing of Optical Signals

Aimed at the problems of optical frequency combs, such as their large number of comb lines, their high flatness, and their lack of ease in generating, as well as the fact that the channelization efficiency of the scheme based on optical frequency combs is low, we proposed a microwave photonic channelization receiver based on signal polarization multiplexing. Using two-line local optical frequency combs with different frequencies to demodulate the RF signal in the orthogonal polarization state, 16 sub-channels with a bandwidth of 1 GHz can be received simultaneously. The experimental results show that the image rejection ratio can reach 28 dB, and the third-order spurious-free dynamic range of the system can reach 96.8 dB·Hz2∕3. This scheme has the advantages of a large number of sub-channels and a high channelization efficiency; it has great application potential in broadband wireless communication, radar, and electronic warfare systems.

Performance comparison of various end-to-end learning technologies with a bandwidth-limited OWC system

Recently, end-to-end (E2E) learning methodologies have garnered significant attention as a compelling approach to attain global optimal communication within the domain of 6 G native intelligent systems. Nevertheless, a precise evaluation of the diverse E2E techniques is still lacking, leading to uncertainties regarding their applicable scenarios and effectiveness. In this paper, we present a comprehensive comparison applying three advanced E2E methods including the autoencoder-based geometric shaping (AEGS) model, comprehensive autoencoder (CAE) model, and wave-wise auto-equalization (WWAE) model in a real bandwidth-limited optical wireless communication (OWC) system. A novel attention-based comprehensive noise joint channel estimator (ACNJCE) is proposed to serve as a universal channel model adaptable to the existing E2E methods. Based on traditional carrier-less amplitude and phase modulation (CAP) modulation, AEGS, WWAE, and CAE are compared under the conditions of 2 GBaud and 3 GBaud respectively. The final results demonstrate that the CAE exhibits the capability to autonomously allocate bandwidth and achieves the highest dynamic adjustment range, which is increased by 69% compared with CAP based on neural network (NN) equalization. In contrast, AEGS has obvious advantages in terms of received optical power (ROP) gain. Based on bit-power loading discrete multi-tone modulation (DMT) modulation, WWAE can effectively compensate the signal spectrum after modulation order optimization and finally achieves the highest data rate under the condition that the −3 dB bandwidth of the channel is only close to 1 GHz. The BER of WWAE with DMT at this rate is 25.2% of that using the NN equalization. Furthermore, experimental results under turbulent conditions reveal that AEGS exhibits superior and more stable performance amidst the perturbations caused by turbulence due to its ability to achieve end-to-end autonomous optimization while integrating traditional modulation and bringing additional shaping gain. According to our knowledge, this marks the first comprehensive evaluation and comparison of existing major E2E algorithms and traditional communication algorithms in a real OWC system.

Performance Evaluation of CF-MMIMO Wireless Systems Using Dynamic Mode Decomposition

Cell-Free Massive Multiple-Input–Multiple-Output (CF-MIMO) systems have transformed the landscape of wireless communication, offering unparalleled enhancements in Spectral Efficiency and interference mitigation. Nevertheless, the large-scale deployment of CF-MIMO presents significant challenges in processing signals in a scalable manner. This study introduces an innovative methodology that leverages the capabilities of Dynamic Mode Decomposition (DMD) to tackle the complexities of Channel Estimation in CF-MIMO wireless systems. By extracting dynamic modes from a vast array of received signal snapshots, DMD reveals the evolving characteristics of the wireless channel across both time and space, thereby promising substantial improvements in the accuracy and adaptability of channel state information (CSI). The efficacy of the proposed methodology is demonstrated through comprehensive simulations, which emphasize its superior performance in highly mobile environments. For performance evaluation, the most common techniques have been employed, comparing the proposed algorithms with traditional methods such as MMSE (Minimum Mean Squared Error), MRC (Maximum Ration Combining), and ZF (Zero Forcing). The evaluation metrics used are standard in the field, namely the Cumulative Distribution Function (CDF) and the average UL/DL Spectral Efficiency. Furthermore, the study investigates the impact of DMD-enabled Channel Estimation on system performance, including beamforming strategies, spatial multiplexing within realistic time- and delay-correlated channels, and overall system capacity. This work underscores the transformative potential of incorporating DMD into massive MIMO wireless systems, advancing communication reliability and capacity in increasingly dynamic and dense wireless environments.

The smart enhancement of near field sensing range for terahertz antenna in 6G wireless communication systems

The smart enhancement of near field sensing range for terahertz antenna in 6G wireless communication systems

A 4 × 20 Gbps inter-satellite optical wireless communication system based on orbital angular momentum multiplexing: performance evaluation

A 4 × 20 Gbps inter-satellite optical wireless communication system based on orbital angular momentum multiplexing: performance evaluation

BER and outage throughput analysis of DPIM/DHPIM coded QPSK-OFDM based outdoor optical wireless communications

With the growing demand for fast and reliable communication systems, particularly in outdoor environments, it is essential to investigate advanced encoding techniques. Digital Pulse Interval Modulation (DPIM) and Dual Header Pulse Interval Modulation (DHPIM) emerge as promising alternatives to traditional line coding methods, providing enhanced spectral efficiency and resistance to signal disruptions. This paper presents the performance of a Quadrature Phase-Shift Keying (QPSK) Orthogonal Frequency Division Multiplexing (OFDM)-based Optical Wireless Communication (OWC) system using these advanced encoding schemes. The analysis includes simulation results on QPSK-OFDM-based transmitter design, free space optical channel modeling based on Gaussian and log-normal distribution atmospheric turbulence, and recovery of input digital stream using the mentioned line coding techniques. The results demonstrate optimal bit error rate (BER) values for the QPSK-OFDM-based OWC system. The primary innovation of this research lies in the encoding schemes and their performance in outdoor optical wireless communication systems under turbulent conditions. Through extensive simulations and analysis, detailed insights into the bit error rate and outage throughput characteristics of DPIM/DHPIM coded QPSK-OFDM are provided, offering a unique perspective on the performance of these schemes in real-world scenarios. The findings not only highlight the optimal BER values achievable with the QPSK-OFDM-based OWC system but also offer insights into the system's ability to overcome transmission challenges under various atmospheric conditions.

H-Shape Microstrip Patch Antenna: Design, Simulation, and Characterization

This paper presents the design, simulation, and characterization of an H-shape microstrip patch antenna intended for high-frequency applications. The proposed antenna is modeled using Computer Simulation Technology (CST) Microwave Studio, a powerful tool for simulating electromagnetic fields and optimizing antenna parameters. The H-shaped configuration is chosen to enhance the antenna's radiation characteristics, bandwidth, and gain, while minimizing size and surface wave effects. The design process involves parameter optimization, including substrate selection, patch dimensions, and feed point configuration, to achieve superior performance. Detailed simulation results are presented, demonstrating the antenna's return loss, VSWR, gain, and radiation pattern. The antenna operates efficiently with stable resonance, offering low return loss and high radiation efficiency. The simulation results confirm that the H-shape microstrip patch antenna is well-suited for various wireless communication systems, showing potential for integration in compact, high-performance devices. This paper serves as a step towards further optimization and practical implementation of H-shape microstrip antennas in advanced RF systems.

Design of wireless charging system for E-Vehicle

To address the dual problems of fuel reliance and air pollution, this study describes the design of a wireless ground to vehicle charging system powered by solar energy and specifically designed for electric vehicle (EV) charging stations. As the number of electric vehicles on the road steadily rises, they present a viable way to cut travel expenses by switching from conventional fuel to electricity, which is a more economical and sustainable option. With the introduction of a wireless EV charging system, this creative solution does away with the need for external power sources and permits continuous charging without interfering with driving. Utilizing solar power, the charging system incorporates solar panels, batteries, circuit regulators, boost converters, receiver and transmitter copper coils, AC/DC converters, microcontrollers (such as ATmega), LCD screens, and circuit regulators. This study describes a technique that shows that charging electric cars while driving is feasible and eliminates the need to stop. This technology for wireless solar electric vehicle charging presents a forward-thinking approach to sustainable mobility by providing a workable solution that can be easily included in the road infrastructure. For the wireless charging, in addition, various coil designs are suggested.