Digital Wireless Communication Systems Research Articles

A battery-free, wireless, flexible bandlike e-nose based on MEMS gas sensors for precisely volatile organic compounds detection

Real-time detection of VOCs in the car cabin is crucial for protecting driver’s health. MOS gas sensors, with the advantages of low cost, simplicity and fast response, are widely used for gas monitoring. However, they typically exhibit broad-spectrum responsiveness to multiple gases. Despite numerous improvement strategies proposed from the perspective of MOS material modification, achieving ideal gas selectivity remains challenging. An e-nose based on gas sensor array is a promising approach for gas identification. However, the hardware circuit system and battery supply module in traditional e-nose result in large size, complex structure, and inconvenience in use. In this work, we synthesized MOS materials with different morphologies to form a microarray containing six MEMS gas sensors, and developed a novel belt-shaped wireless and battery-free flexible e-nose, where a mobile phone serves as its wireless power supply and data communication system. This design provides a flexible e-nose with excellent wearability and safety, allowing users to monitor surrounding gas conditions at any time conveniently. Subsequently, we design pattern recognition models using algorithms such as MLP, RF, XGBoost, and LGBM, in combination with ensemble learning strategies, achieving high accuracy in VOCs classification and low-error concentration prediction. This flexible e-nose holds significant application value for gas detection in car cabins and indoor environments.

Optimized Design of an Ultrasonic-Based High-Efficiency Wireless Passive Monitoring System for Sealed Metal Compartments.

The condition monitoring (CM) of sealed metal compartments (SMCs) is an urgently required restructure. Ultrasound penetrates SMCs to power and communicate with built-in sensors, enabling the CM of SMCs. However, current ultrasonic wireless power transfer and data communication (UWPTADC) systems are large and complex, and limited by the efficiency of energy transfer and data reliability. In this paper, an optimized design of a high-efficiency wireless passive monitoring system using UWPTADC techniques is proposed for SMC. The circuit model of the system is developed and analyzed to achieve an optimal design for efficient wireless power transfer and effective data communication coupling. A test system was constructed using a steel wall of 11 mm thickness as a validation object. At the ultrasonic carrier frequency of 1.045 MHz, the system has an energy transfer efficiency of 60%, and a communication rate of 50 kbps. In addition, the system realizes temperature and humidity monitoring inside a 13 mm thick cylindrical SMC, simulating the process of ultrasonic CM of an actual engine compartment. The system provides a wiring-free and battery-free solution for CM in SMCs, advancing CM in aerospace, marine and other fields.

The Small UWB Monopole Antenna with Stable Omnidirectional Radiation Pattern

Ultra Wideband (UWB) technology is an unmodulated wireless digital communication system that uses an extremely short duration pulse to transmit information bit. Because of this pulse, the UWB system needs a very wide bandwidth. Federal Communication Commission (FCC) has regulated the 3.1 – 10.6 GHz frequency spectrum for UWB. Since FCC released this frequency, many research in telecommunication have been done on UWB systems. One of them is a development of an Antenna that is suitable for UWB devices. UWB antenna characteristics require FCC band, omnidirectional radiation pattern, and compact size. In order to meet these needs, an antenna with a simple structure in the form of a monopole patch antenna with a similar patch size and ground width has been designed. The antenna is built on an FR4 – epoxy substrate material, with 4.4 dielectric constant and 1.6 mm thickness. The antenna feeding structure consists of two 100 Ω and 50 Ω lines with a wideband impedance matching scheme using tapered side and tapered transformers. The antenna design and optimization processes are conducted using electromagnetic simulation software, and measurements are carried out in an anechoic chamber. Simulation and measurement results show good agreement, and the antenna can work at frequencies 3.5 - 11.3 GHz with a gain of 1.5 – 3.25 dBi and stable omnidirectional radiation patterns. The antenna has dimensions of 27 × 8 × 1.6 mm, which are smaller than the antenna reported in the last research and suitable to be applied on various UWB devices.

A Low-Cost Laboratory Practice for Fundamental Learning of Wireless Digital Communication

Several studies have shown that the main challenge in teaching complex systems involving many theoretical backgrounds to senior students is their lack of confidence. In this paper, we present an approach to the teaching methodology of an undergraduate course in a telecommunication study program. The first goal of this methodology is to help students understand the theoretical concepts behind wireless digital communication systems through direct practice to give them more exposure to a real system through affordable practice activities in an experiential context, utilizing an HF radio and a single-board computer (SBC). The second goal is to challenge senior students to understand the data link layer by using white box testing of the syntax of the programming language embedded in the SBC. This approach is ideally carried out based on offline and hands-on class activities, however, the pandemic condition made it unavoidable to do it online using a demonstration model. Feedback from students was collected through written comments, post-testing, including a facility index analysis, and a questionnaire that was distributed using the available e-learning system. The post-test results showed that the average score was 72 out of a maximum of 100.

Анализ передачи дискретных сообщений в системах мультиплексирования с ортогональным частотным разделением каналов

High data transfer rates are required in modern digital radio transmission systems. But an increase in the data transfer rate leads to a deterioration in the transmission quality and a high BER (bit error rate). OFDM technology, which was introduced in the 1960s, implements all these functions. In this paper, the influence of fading channels on the transmission of information in OFDM systems is investigated. In wireless systems for transmitting discrete messages, the channel parameters greatly affect the transmission quality, as interference, noise and fading affect the useful signal. Fading is a very common phenomenon in wireless communication systems, affecting the phase shift of the signal. In an urban environment, multipath propagation of signals also takes place, since signals propagate along two or more paths before reaching the receiver. Depending on the signal propagation medium and communication conditions, small-scale fading can be distinguished. At the same time, there are significant changes in the amplitude and phase of the signal. Small-scale fading occurs on a smaller scale, comparable to the wavelength of the transmitted signal, and often changes throughout the signal path, and may change one or more times during the transmission time of the symbol, which leads to so-called flat (smooth) and frequency-selective fading. The results obtained show the effect of fading on the digital transmission system (OFDM). The three discrete message delay profiles used represent a low-, medium-, and high-latency propagation environment, respectively. A model of a wireless digital communication system (OFDM) has been built using the SystemVue software.

Transmisi Data Citra pada Sistem Komunikasi Nirkabel dengan Teknik MIMO

Wireless data communication systems using Multiple Input Multiple Output (MIMO) technique in its transmission system has been well developed to solve many transmission media problems. This study aims to analyse the performance of MIMO 2x2 and MIMO 4x4 using image data. Encoding technique that is used in this study is Space Time Block Coding (STBC) by Alamouti. The result of this study shows that wireless communication system using MIMO technique is able to recover the image data on the receiver side the same as the image data on the transmitter side when SNR = 6.5dB for MIMO 2x2 and SNR = 4.5dB for MIMO 4x4.

Construction of a Cu-Sn Heterojunction Interface Derived from a Schottky Junction in Cu@Sn/rGO Composites as a Highly Efficient Dielectric Microwave Absorber.

Developing high-performance dielectric absorbers, low filler loading, and a broad absorption band remains a great challenge for wireless data communication systems, household appliances, local area network, and so on. Herein, we report a facile green method to design and fabricate a copper-coated tin/reduced graphene oxide (Cu@Sn/rGO) composites with a heterojunction obtained by modifying a Schottky junction. The unique heterojunction can enable an appropriate balance between impedance and strong loss capacity. Meanwhile, it can not only promote the carrier migration but also obtain the rich interfaces. Consequently, a Cu@Sn/rGO composite with a heterojunction exhibits superior absorption intensity, far surpassing that of other absorbing materials reported. With a weight content of only 5 wt %, the maximum absorptivity reaches -49.19 dB at 6.08 GHz, and an effective absorption bandwidth (RL < -10 dB) of 13.94 GHz is achieved when the absorber's thickness ranges from 1.7 to 5.5 mm. This study provides new insights into the design and synthesis of a novel microwave absorption material with lightweight, smaller filler loading, and strong reflection loss.

Wireless Power and Data Transmission for Implanted Devices via Inductive Links: A Systematic Review

Wireless power and data communication systems in implantable medical devices (IMDs) are developed to control and report acquired biological data from an implanted device to an external stage in several medical applications. Ultrasonic, capacitive, optical, radio frequency (RF), and inductive links are employed as a wireless power and data transmission technique. Inductive power transfer (IPT) is one of the most commonly used techniques due to its robustness, simplicity, safety, and capability of simultaneous and bidirectional data and power transmission. This paper presents a systematic review and survey of the latest inductive power and data transmission methods for IMDs. The fundamental principles of remote powering through inductive links, the critical parameters of design, and power transfer efficiency calculations are presented. Single and multiple inductive links, the advantages and drawbacks, optimization methods, and comparison by their performances are explored. In addition, modulation schemes, along with improvement techniques reported in the literature, the strengths and limitations, and the measured or the simulated data rate of each are also reviewed. A benchmarking table with summarized design features of systems, essential parameters for wireless powering and data communication, and categorized Figure-of-Merits (FoMs) to compare performances are also provided.

Error Correction LDPC Encoder with Bit-Flipping Decoder

The communication method conveys information from the transmitter to the receiver over an intermediate medium. The competence of received information is determined by medium and clatter. There is a great need for robust error correction techniques with ever accumulative usage of wireless expedients such as portable electronic items and broadband modems. Wireless communication schemes depend on advanced error rectification techniques for their suitable functioning. Hence transferring and getting information with less or without error, while utilizing the accessible bandwidth is a foremost proposal, project necessities for present digital wireless communication systems comprising of high throughput, low power consumption, and less area. In this article, the functional analysis is performed for error control coding technique i.e., Low-Density-Parity-Check (LDPC) coding in terms of device utilization and power. The functional verification and the simulation are performed using Verilog HDL. Error correction techniques such as Linear block codes, RS codes, Convolutional codes are employed to implement forward error correction but as the constraint length increases the design of decoders becomes more complex. LDPC is a type of block code that is capable of correcting random errors. They are popular because of their eminent detection and correction capabilities. LDPC encoding technique provides high throughput and aims to improve BER when compared to conventional techniques. The decoding of LDPC codeword employs the Message Passing Algorithm, where each bit in a codeword is allocated to special nodes. The performance of these codes is hence better and easily attains Shannon’s limit than the previously used codes. Synthesis for the technique is performed and utilization reports are derived from the synthesis in Vivado.

Absorptive filter integrated single pole double throw switch using switchable ring resonator

In this paper, a reconfigurable ring resonator-based filter integrated switch (FIS) was presented. The FIS was made up of two absorptive ring resonators, reconfiguring between band-stop and band-pass responses, and integrated with single pole double throw (SPDT) switch. A simple mathematical analysis of isolation and insertion loss of filter-integrated SPDT switch was discussed. PIN diodes were used as the switching elements for the SPDT switch and to reconfigure between the band-stop and band-pass responses. The proposed absorptive FIS design could be used for wireless data communication systems such as Zigbee and Bluetooth at an operation frequency of 2.45 GHz. As a result, the proposed FIS exhibited 2 dB of insertion loss and better than 38 dB of isolation. Therefore, the key advantages of the proposed FIS design are low insertion loss, high isolation and good return loss at both ON- and OFF-state ports.

Wireless power and data transfer through carbon composite using a common inductive link

This paper presents the design and development of an integrated wireless power transfer and data communication system. The power and data transfer share a common inductive link that consists of two identical Helical coils placed on both sides of a carbon composite barrier. Power and data are transferred simultaneously through a 5-mm thick carbon composite barrier without any physical penetration or contact. Power transfer measurements show that the system can deliver 9.7 AC power to the receiving coil with a power transfer efficiency of 36% through the carbon composite barrier. The system achieves a bidirectional half-duplex data communication with the data rate of unit 1.2kbit/s.

Low complexity based scheduling methods for multi-user MIMO systems

The process of joint user and receive antenna scheduling is very vital in the uplink direction of multi-antenna wireless data communications system with multiple users. With higher number of receive antennas and active users, the search space becomes huge for the joint user and receive antenna scheduling process. It is very difficult to accomplish the searching through the entire search space within the wireless communication time frame. In this paper, low complexity based methods for joint scheduling of users and receive antennas have been proposed. Here, this has been shown that low complexity based scheduling scheme is able to attain system throughput which is quiet close to that of exhaustive search algorithm (by searching the entire search space). Moreover, an interesting observation can be made that the number of complex multiplications and additions required by these low complexity methods is quite less than that of exhaustive search algorithm.

Asymmetric Entrainment Structure of Pierce Oscillator Circuit

Experimental study is presented to uncover entrainment property of Pierce oscillator circuit (i.e., one of the most standard circuits for crystal oscillators) subject to sinusoidal external forcing. In contrast to the well-known Arnold tongues observed in a wide class of forced nonlinear systems, asymmetric shape was observed as an entrainment region of the circuit in two-dimensional parameter space spanned by the external forcing strength and frequency. Computation of the impedance curve revealed that the asymmetric shape is due to positive (inductive) or negative (capacitive) reactance of the Pierce circuit, which facilitates or inhibits the circuit oscillations. We extend this insight into two coupled Pierce circuits and show that, to efficiently achieve their synchronization, it is advantageous to drive a slow oscillator circuit by a fast circuit rather than to drive a fast circuit by a slow circuit. Our study provides a guideline on an optimal network configuration for coupled crystal oscillators, which may find applications in distributed digital clocks and wireless communication systems.

Generic Wireless Power Transfer and Data Communication System Based on a Novel Modulation Technique

This paper presents a wireless power and downlink data transfer system for medical implants operating over a single $10~MHz$ inductive link. The system is based on a Carrier Width Modulation (CWM) scheme for high-speed communication and efficient power delivery using a novel modulator circuit design. Unlike conventional modulation techniques, the data rate of the proposed CWM is not limited by the quality factors of the primary and secondary coils. The functionality of the new modulation method is proven using a hybrid implementation comprising a custom-integrated demodulator circuit and board-level discrete components. The proposed Wireless Power and Data Transfer (WPDT) system is also capable of operating under a wide range of data rates. It allows a maximum data rate of $3.33~Mb/s$ for a maximum power delivery of $6.1~mW$ at $1~cm$ coils separation distance. The system can recover more power, reaching $55~mW$ at $100~kb/s$ . Due to the system genericity, an operator can select the best compromise between power and data rates in accordance to application or current need, without reconfiguring the receiver. Another advantage of this modulation technique is the simple implementation and the ultra-low power consumption of the CWM demodulator despite its high-speed demodulation.

Wireless Sensor Network Data Communication and Information system to Regulate Water Volume and Turbine Rotation

The increasing need for electrical energy makes innovation in creating alternative energy is needed to help meet the needs of electrical energy that is more efficient and environmentally friendly. Therefore, the selection of water turbines as alternative energy because the cost of building hydropower is relatively low and environmentally friendly, making it a competitive source for renewable energy. Wireless Sensor Network (WSN) is a wireless network consisting of several sensor nodes that are individual that are used to monitor the condition of a place and can interact with its environment by means of sensing, controlling and communication to its physical parameters. The application of WSN to water turbines as a power plant is used to control and remotely monitor water turbines. So that it allows users to get maximum information and is real time without having to be in the sensor area. The programming used for this tool is the Basic Compiler AVR and Virtual Basic to display data in the form of graphs. Then the programming will be analyzed which has been entered at ATMega128 and ATMega8, which is programming to measure the height of the water tank and control the output of the tool.

Automatic Guided Waves Data Transmission System Using an Oil Industry Multiwire Cable.

Alternative wireless data communication systems are a necessity in industries that operate in harsh environments such as the oil and gas industry. Ultrasonic guided wave propagation through solid metallic structures, such as metal barriers, rods, and multiwire cables, have been proposed for data transmission purposes. In this context, multiwire cables have been explored as a communication media for the transmission of encoded ultrasonic guided waves. This work presents the proprietary hardware design and implementation of an automatic data transmission system based on the propagation of ultrasonic guided waves using as communication channels a high-temperature and corrosion-resistant oil industry multiwire cable. A dedicated communication protocol has been implemented at physical and data link layers, which involved pulse position modulation (PPM), digital signal processing (DSP), and an integrity validation byte. The data transmission system was composed of an ultrasonic guided waves PPM encoded data transmitter, a 1K22 MP-35N multiwire cable, a hardware preamplifier, a data acquisition module, a real-time (RT) DSP LabVIEW (National Instruments, Austin, TX) based demodulator, and a human-machine interface (HMI) running on a personal computer. To evaluate the communication system, the transmitter generated 60 kHz PPM energy packets containing three different bytes and their corresponding integrity validation bytes. Experimental tests were conducted in the laboratory using 1 and 10 m length cables. Although a dispersive solid elastic media was used as a communication channel, results showed that digital data transmission rates, up to 470 bps, were effectively validated.

DESIGN OF THE DATA TRANSMISSION BETWEEN THE EXERSICE SMART MINE WITH GROUND STATION USING LORA

Wireless data communication system through communication radio is one of the important points of informationdelivery process in TNI AL, It relates to the process of delivering information on the field that is difficult to obtaincommunication network via internet. The use of portable and strong communications against jammedinterference and other adjacent frequency interference becomes a fundamental necessity. The use of the UHFfrequency communication system is one of the efficient communication, With the high frequency of positivelyresulting in the physical size of the antenna is increasingly smaller. The purpose of designing datacommunication system devices between exercise smart mine and the ground station using Lora. In planning thiscommunication system uses the Lora SX1278 module as a data transmitter (Tx) and receiver data device (Rx).On the transmitter side (Tx) Lora uses the Arduino Mega 2560 microcontroller as the core or brain system. Onthe side of the receiver (Rx) Lora uses Arduino Uno R3 as the process data unit received by the Lora receiver.The main function of Arduino Uno as an intermediary to be able to transfer data to a PC or laptop device as aground station monitoring through USB communication channels. From the design, testing, and discussion ofresearch results during the preparation and manufacture of this final task obtained the results as expected. Thatthe design of data communication systems using Lora can be obtained a maximum range of 200 meters withthe condition of building obstructed. The ability of the Lora SX1278 module to receive data and transmit datafrom the GPS, pressure sensors and acoustic sensors is well received by the ground station, based on the datatransmitted via the Lora SX1278 module transmitter.Keywords: Lora SX1278, Arduino Mega 2560, Arduino Uno R3

Research progress of information metamaterials

&lt;sec&gt;Metamaterials are artificial structures composed of subwavelength unit cells in periodic or non-periodic arrays, which are regarded as one of the most important tops in today’s physics and information engineering. Traditional metamaterials are characterized by effective medium theory, in which the array of differently-shaped subwavelength particles can be described as an effective medium with effective permittivity and permeability. The metamaterials allow us to engineer the medium parameters with unusual values, such as negative permittivity and permeability, zero index of refraction, etc. In 2014, Cui et al. (Cui T J, Qi M Q, Wan X, Zhao J, Cheng Q 2014 &lt;i&gt;Light-Sci. Appl.&lt;/i&gt; &lt;b&gt;3&lt;/b&gt; e218) proposed the concept of information metamaterial, which is a digital version of the metamaterial with each unit cell described by digital codes representing different reflection/refraction phases. The direct connection between information metamaterials and digital logic devices allows the dynamic controlling of the electromagnetic (EM) waves by real-time programming the digital states of each unit cell in the information metamaterials with preloaded digital coding sequences. As information metamaterials build up a digital world (digital coding information) directly in the physical world, digital information can be processed on the information metamaterials directly without any intermediate conversion process, thus realizing the unification of microwave engineering and digital processing.&lt;/sec&gt;&lt;sec&gt;In this paper, we review the recent developments of digital coding metamaterials, programmable metamaterials, and information metamaterials, mainly focusing on their basic concepts, working mechanisms, experimental realizations, and system-level applications. Firstly, we introduce the concepts of digital coding and programmable metamaterials and present their advantages to realize the dynamic controlling of EM waves at low cost. The working mechanisms of isotropic, anisotropic, and tensor digital coding metamaterials are described, following the first prototype of the programmable metamaterial. Then we introduce the concept of information entropy for the information metamaterial and reveal the connection between the amount of information carried by the coding pattern and the radiated field of the information metamaterial. Convolution operation and addition theorem are further presented to show their powerful manipulations of EM wave in generating arbitrary beam patterns pointing to arbitrary directions. Finally, we introduce three representative system-level applications of information metamaterials, including a reprogrammable hologram imaging system which can dynamically project different microwave images at the imaging plane through the preloaded coding sequences stored in field programmable gate array (FPGA), a machine-learning reprogrammable metasurface imager that can be trained &lt;i&gt;in-situ&lt;/i&gt; to produce high-quality images and high-accuracy object recognition in the real case at low cost, and directly digital wireless communication systems, in which the digital information is directly processed and radiated to free space by using the information metamaterial and FPGA. The information metamaterials are currently advancing towards higher frequencies (millimeter waves, terahertz, and infrared) to have higher capacity of information, and are becoming more “intelligent” with the combination of many advanced algorithms in computer science. We believe that the future information metamaterials possess signatures of self-sensing, self-learning, self-adaptive, and self-decision.&lt;/sec&gt;

An Educational Model of Graduation Project for Students at Automation and Computer Engineering

The upcoming engineers, students at Automation and Computer Engineering, acquire, during four years of education, a tremendous theoretical information in different areas connected with their educational field of study. From solid mathematical backgrounds to electronics and automation and many other subjects become a stock of incredible useful database for future engineers. The lack of adequate practical work that allow them to connect and get aware on how to use information acquired, lead, in most of the situation, to a useless database of information. This paper presents a model of a good practice work and aims to be a useful example for students in the last year of study on how to handle and realize, starting from one idea and finishing with a working prototype, their graduation project. The example here is a low cost, handy, a real time data acquisition and duplex wireless data communication system. It consists of two modules. The first one is a glove used by an operator, equipped with an Arduino board with a gyroscope, accelerometer and full duplex communication parts that sends movements commands to a mobile robot. The mobile robot is equipped with a camera sending video streaming related to the immediate space and a network of sensors with the aim to acquire environmental data and sent them remotely to the first module.

The State of the Art in CMOS VCOs: Mm-Wave VCOs in Advanced CMOS Technology Nodes

There is a growing interest in the realization of highly integrated radar transceivers operating at millimeter-wave (mm-wave) frequencies. In this case, CMOS is the natural technology choice. Modern nanoscale CMOS technologies offer excellent transistor performance with transit frequencies ( f T ) and maximum oscillation frequencies ( f max) exceeding several hundreds of gigahertz. This enables the realization of highly integrated, digitally intensive transceiver systems on chip for mmwave applications, such as 77-GHz automotive radar [1] or wireless data communication systems [2]. Several advanced nanoscale CMOS nodes even surpass the f T and f max values achieved by silicon germanium (SiGe) heterojunction bipolar transistor technologies [3].