Digital Modulation Method Research Articles

A Small-Sized High-Precision Digital Closed-Loop Modulation Method for Dead-Time Compensation for Flying Capacitor Three-Level Inverters

A Small-Sized High-Precision Digital Closed-Loop Modulation Method for Dead-Time Compensation for Flying Capacitor Three-Level Inverters

Performance Analysis of OFDM under Rician Fading Channel using Various Digital Modulation Methods

The widespread use of mobile platforms has resulted in significant challenges related to power constraints and the Quality of Service(QoS) provided by Orthogonal Frequency Division Multiplexing (OFDM) systems. The examination of Bit Error Rate (BER) and Signal-to-Noise Ratio (SNR) is of significant importance in comprehending and enhancing the design of OFDM systems. The utilization of wireless technology in everyday life has experienced a gradual and consistent growth. OFDM is a prevalent technique for multicarrier transmission, which effectively utilizes parallel data streams. OFDM is considered an effective technique for achieving high-speed digital transmission over channels that exhibit time-varying characteristics. OFDM has several advantages compared to single carrier modulation. These include enhanced resistance to impulsive interference, increased spectral density, improved resilience to channel fading, greater tolerance to multipath effects, and reduced computational complexity. Nevertheless, OFDM has some notable challenges that hinder its practical use in telecommunications networks. Several examples of these are packet loss, bit loss, peak-to-average power ratio (PAPR), BER, and SNR. This research aims to investigate the BER and SNR performance of OFDM in the presence of Rician Fading Channel. The study also explores the impact of different modulation techniques on the performance of OFDM.

Computer-Generated Holography Methods for Data Page Reconstruction Using Phase-Only Medium

Achievements in the field of high-speed spatial modulation electrooptic components provide the possibility to create perspective optical-digital diffractive systems for information storage and processing that outperform modern electronic counterparts by utilizing throughput, energy efficiency, and reliability. This work presents a study of computer-generated holography methods that allow the formation of spatially-modulated information signals (data pages) with high accuracy using phase-only spatial light modulators. Computer-generated Fourier hologram fringe patterns were formed using bipolar intensity and double-phase coding. Numerical and experimental results of both methods’ implementation are compared. It was determined that bipolar intensity holograms provide higher data density on the data page if complex digital modulation methods such as multilevel amplitude and phase or quadrature modulation are used to represent data points. Double-phase coding can offer perspective for multilevel amplitude or multilevel intensity modulated data page reconstruction; however, exact control of phase modulation characteristics is required to obtain high reconstruction quality.

Cost-Efficient RIS-Assisted Transmitter Design With Discrete Phase Shifts for Wireless Communication

In this letter, in order to achieve higher spectral and energy efficiency, we propose a novel cost-efficient transmitter conceptual design based on reconfigurable intelligent surface (RIS) with discrete phase shifts. The key idea is to directly utilize the digital signal to adjust the discrete reflection coefficients of RIS, resulting that the phases of the reflected carrier signal being modulated without the need for complex digital signal processing (DSP) hardware and costly radio frequency (RF) chains. Furthermore, a joint digital modulation and beamforming method is developed to enable information transmission as well as enhance signal strength. Based on the proposed transmitter, we derive the closed-form expressions of the signal-to-noise ratio (SNR) and bit error rate (BER) of the received signal and analyze the impact of hardware constraints on communication performance. Extensive simulation results validate that the novel design of RIS-assisted transmitter provides a cost-effective and power-efficient solution for wireless communications.

A New RF Satellite Link Analyzing and Antenna Effect on Satellite Communication

Satellite communications (SatComs) recently, have admitted as a new technological advances that attracted and raised special investment and ventures. Space communication technology has found many application areas from costly, one-of-a-sort structures, to utilize again of technology on sequential tasks, to the progress of canonical protocols accepted by space agencies of lots of countries. Satellite communication has accepted as one of the important technologies for 5G backhauling, particularly on bandwidth request increased in 5G mobile broad band (eMBB) applications. This paper presents the efficiency of the satellite communication system using 16 QAM digital modulation technique for the X band. This digital modulation method presents high data rate in transmission without raising the bandwidth compared with other digital modulation methods. Applications are realized in Matlab environment and obtained conclusions are discussed such as power spectrum diagrams, constellation schemas and BER ratio for several bands such as 4, 8, 12, 16 GHz.

Method for Estimating and Compensating the Phase Imbalance of Quadrature Signal Components

Currently, methods of direct modulation using complex signals are widely used. A complex signal consists of in-phase I (In-phase) and quadrature Q (Quadrature) components. When a signal passes through a communication channel and a receiving path, mismatches of the signal components occur as a result of interference. The mismatch, in turn, leads to increase in bit error rate (BER) during signal demodulation. The quality of the received signal is expressed in terms of bit error rate. The article considers phase imbalance of the quadrature components of a complex signal. Phase imbalance occurs in the receive path and depends on the quality of the receiver's local oscillators, on the operating temperature and the difference in propagation time of the I and Q components. The article shows an algorithm for estimating the phase imbalance of the quadrature signal components for digital modulation methods. Examples of signal constellation distortions in case of phase imbalance of quadrature signal components are considered. The phase imbalance estimation is based on the modulation constellation method for measuring signal parameters. Formulas for calculating the angle of phase error and the magnitude of quadrature error are given. Formulas for compensating the phase imbalance are also given, taking into account the calculated quadrature error. A mathematical model of the transmitter, communication channel and receiver has been developed to study the method for estimating and compensating for phase imbalance. The mathematical model is built in the Matlab software environment and is an m-script software model. With the help of the mathematical model, method for estimating and compensating for phase imbalance has been studied. In the course of the study, relationships of error probability due to the mismatch of the quadrature components of the signal were obtained. The noise immunity of the receiver paths with and without compensation for the phase mismatch of the quadrature signal components is compared. Based on the results of the study, diagrams of the error probability and the phase mismatch of the receiver's local oscillators were obtained. The study shows that phase mismatch of the receiver local oscillators at a fixed signal-to-noise ratio leads to an increase in the probability of received bit errors. But when applying the phase imbalance compensation method, the error probability remains fixed as the phase mismatch of receiver local oscillators increases at a fixed signal-to-noise ratio.

WAYS OF INCREASING THE RELIABILITY OF MESSAGE TRANSMISSION IN INFORMATION AND COMMUNICATION SYSTEMS USING ONE-WAY RADIO CHANNELS

Modern information and communication systems which use one-way radio channels have the main task to maximize the reliability and information transmission stealth. This task becomes more relevant in conditions of the radio-electronic warfare and growing of the cyber incidents with wireless vulnerabilities exploitation. This solution is useful for Internet of Things technologies with one-way interaction protocols and unmanned aerial vehicle control systems for organization and critical infrastructure cyber security support.The purpose of this work is the fading of possible ways for increasing of the message transmission reliability in the information and communication systems with one-way radio channels.The examples of digital modulation methods applications, interference-resistant coding which are used in modern information and communication technologies with one-way radio transmission are considered in the article. In the work were received results of digital modulation methods and interference-resistant coding analysis with minimum bit error rate criterion. The usage futures of combined random coding which is based on interference-resistant and stochastic coding combination were researched.Standard random bit generators were tested by the NIST Statistical Test Suite 2.1.2 application.This research results give us the possibility to increase the reliability of message transmission by way using binary phase-shift keying in combination with majority coding. In this case we should solve tasks to improve the phase estimation schemes of received signal and optimal choice of majority coding redundancy.In order to increase the reliability and information stealth of message transmission the using of combined random coding was proposed. At the same time, we recommend to use Blum-Blum-Shub random bit generator for the codebook creating. Blum-Blum-Shub random bit generator was chosen according to estimation results, obtained with the help of NIST Statistical Test Suite.

Active-Matrix Micro-LED Display Driven by Metal Oxide TFTs Using Digital PWM Method

This article presents a new micro-light-emitting diode (LED) pixel circuit driven by the digital pulsewidth modulation (PWM) method, in which the threshold voltage compensation of the driving thin-film transistor (TFT) is included. A scan driver integrated by metal oxide (MO) TFTs is also designed to provide the scan signals for pixel circuits array. A micro-LEDs array with <inline-formula> <tex-math notation="LaTeX">$76\,\, \times $ </tex-math></inline-formula> BBB <inline-formula> <tex-math notation="LaTeX">$\times \,\,78$ </tex-math></inline-formula> and a scan driver with 80 stages are simultaneously fabricated by MO TFTs backplane with back-channel etch (BCE) structure. A respective micro-LED display is consequently realized by a peripheral driving system based on a field-programmable gate array (FPGA), which is used as a core control unit to synchronize the scan signals with the data signals. It is shown that the micro-LED in the pixel circuit can operate at a constant current even at the 5-<inline-formula> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> pulsewidth of the emission (EM) signal. The micro-LED display can achieve 256 linear grayscales with an approximately 60 Hz flash rate under the minimum pulsewidth of 40 <inline-formula> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> of EM signal.

A unidirectional frequency beam‐scanning antenna using composite slow‐wave waveguide based on substrate integrated waveguide and spoof surface plasmon polariton structure

In this study, a novel frequency beam-scanning (FBS) antenna based on composite substrate integrated waveguide/spoof surface plasmon polariton (SIW/SSPP) waveguide is proposed. The composite SIW/SSPP slow-wave waveguide is designed by embedding a series of periodic subwavelength H-shaped grooves on the top surface of the SIW. Its transmission characteristics own both the features from SIW and SSPP, and can be flexibly mansplained by tuning the key structural parameters. To convert the propagating composite slow-wave mode into the radiation mode effectively, a new flexible digital modulation method with staggered metallic vias is proposed and used. The presented beam-scanning antenna has a simple feeding structure, a single dielectric layer, and a compact volume of 0.75 × 8.55 × 0.015 λ03. A prototype of the antenna is fabricated and tested to verify its performance. The experimental results demonstrate that the proposed antenna can realise a continuous beam-scanning angle of 49° in an operating bandwidth of 8.7–9.2 GHz with a high frequency-scanning sensitivity (FSS) of 9.8 °/100 MHz−1. Moreover, the measured results indicate that the antenna has high peak gain with an average level of 12.7 dBi, high radiation efficiency with an average level of 87%, and stable unidirectional radiation pattern in the working band.

Automatic recognition of the digital modulation types using the artificial neural networks

As digital communication technologies continue to grow and evolve, applications for this steady development are also growing. This growth has generated a growing need to look for automated methods for recognizing and classifying the digital modulation type used in the communication system, which has an important effect on many civil and military applications. This paper suggests a recognizing system capable of classifying multiple and different types of digital modulation methods (64QAM, 2PSK, 4PSK, 8PSK, 4ASK, 2FSK, 4FSK, 8FSK). This paper focuses on trying to recognize the type of digital modulation using the artificial neural network (ANN) with its complex algorithm to boost the performance and increase the noise immunity of the system.&#x0D; This system succeeded in recognizing all the digital modulation types under the current study without any prior information. The proposed system used 8 signal features that were used to classify these 8 modulation methods. The system succeeded in achieving a recognition ratio of at least 68% for experimental signals on a signal to noise ratio (SNR = 5dB) and 89.1% for experimental signals at (SNR = 10dB) and 91% for experimental signals at (SNR = 15dB) for a channel with Additive White Gaussian Noise (AWGN).

Downlink data transmission for high‐speed trains in 5G communication systems

In this study, a new transmitter–receiver approach for high-speed train (HST) downlink orthogonal frequency division multiplexing (OFDM) data transmission and detection in fifth generation (5G) communication systems is proposed. The proposed method uses a new Doppler shift frequency (DSF) estimation method, proposed in this study, to calculate the channel tap DSFs at the HST receiver. These estimated DSFs are used to calculate the channel taps’ angle of departure (AoD). Using the projected AoDs, the transmitter beamformer adjusts its coefficients to suppress the non-line-of-sight (NLoS) channel taps and a DSF compensation block is used to mitigate the line-of-sight channel tap DSF. Simulation results indicate the fidelity of the proposed DSF estimation method and the proposed transmitter–receiver approach. Due to the accuracy of the proposed DSF estimation method and the effectiveness of the beamformer in suppressing the NLoS channel taps, the approach of using a classic digital modulation and demodulation method instead of the OFDM scheme is appraised. Simulation results indicate that this shift from the OFDM modulation to the classic modulation results in a data detection approach which has acceptable accuracy, low computational complexity, and high spectral efficiency.

Marine Meteorological Data Transmission Evaluation Methods Based on Load Factor Measurement

Wang, X.; Liu, J.X.; Liu, Z., and Dan, H.J., 2020. Marine meteorological data transmission evaluation methods based on load factor measurement. In: Guido Aldana, P.A. and Kantamaneni, K. (eds.), Advances in Water Resources, Coastal Management, and Marine Science Technology. Journal of Coastal Research, Special Issue No. 104, pp. 818–824. Coconut Creek (Florida), ISSN 0749-0208.Since 1970, the lack of timely and efficient marine meteorological data has led to a large number of marine accidents and marine environment pollution. In the past few decades, digital communication technology has developed rapidly and achieved quite successful results. The advanced digital communication technology to transmit marine meteorological data are used. However, the impact of digital modulation methods on marine weather data transmission load rates is unclear. The purpose of this paper is to reveal the digital modulation method under the optimal environment of data transmission load rate. It studies and records 16 modulation methods, including 3 quadrature phase shift keying (QPSK) and 12 amplitude phase shift keying (APSK). It is found that the load efficiency obtained by the APSK modulation method can reach 51.00 Mbps in matlab, which is much higher than the load efficiency obtained from the navigation telex system based on the frequency shift keying (FSK) modulation method. The results show that the marine meteorological data transmission method using the APSK modulation method has the best load efficiency.

Single Photon Compressive Imaging Based on Digital Grayscale Modulation Method

In single-pixel imaging or computational ghost imaging, the measurement matrix has a great impact on the performance of the imaging system, because it involves modulation of the optical signal and image reconstruction. The measurement matrix reported in the existing literatures is first binarized and then loaded onto the digital micro-mirror device (DMD) for optical modulation, that is, each pixel can only be modulated into on-off states. In this paper, we propose a digital grayscale modulation method for more efficient compressive sampling. On the basis of this, we demonstrate a single photon compressive imaging system. A control and counting circuit, based on field-programmable gate array (FPGA), is developed to control DMD to conduct digital grayscale modulation and count single-photon pulse output from the photomultiplier tube (PMT) simultaneously. The experimental results show that the imaging reconstruction quality can be improved by increasing the sparsity ratio properly and compressive sampling ratio (SR) of these gray-scale matrices. However, when the compressive SR and sparsity ratio are increased appropriately to a certain value, the reconstruction quality is usually saturated, and the imaging reconstruction quality of the digital grayscale modulation is better than that of binary modulation.

Simulation and Performance Study of Quadrature Amplitude Modulation and Demodulation System

Both traditional frequency modulation and phase modulation digital modulation methods have low spectral utilization, poor multipath fading resistance, slow power spectrum attenuation, and severe out-of-band radiation. Quadrature Amplitude Modulation (QAM) is a digital modulation technique that combines phase and amplitude control. It not only achieves higher spectral efficiency, but also transmits higher rate data in a defined frequency band. In this paper, the basic principle, system structure and performance parameters of QAM modulation and demodulation are studied in depth to realize simulink simulation and performance analysis of QAM modulation and demodulation system. The basic theory and implementation method of analog signal digitization are analyzed in detail to realize simimlink of differential pulse code modulation. Based on the above theory, the analog source QAM transmission system is constructed, and simulink is used for modeling and simulation and performance verification.The simulation results show that the constructed QAM digital transmission system can achieve good transmission of analog signals.

Performance Examination of OFDM Modulation Techniques in LTE 4G

The digital modulation methods are being chosen in high data rate systems as Long Term Evolution (LTE) and LTE-A. Quadrature Phase Shift Keying (QPSK) and Binary Phase Shift Keying (BPSK) is the simplest form of the PSK with double carrying capacity when compare to the other traditional techniques in modulation. In conventional method the performance was analyzed in MIMO .In this paper proposed the performance analysis of BPSK and QPSK modulator and demodulator in LTE 4G system models under the Additive white Gaussian Noise (AWGN) and Rayleigh fading by comparing the Bit Error Rate (BER). From the analysis, compare to BPSK QPSK has good BER. Using the MATLAB Simulink tool Implementation is performed.

An Improved Area Efficient 16-QAM Transceiver Design using Vedic Multiplier for Wireless Applications

In this research article, an improved area efficient 16-Quadrature Amplitude Modulation (QAM) transceiver design is introduced using Vedic multiplier. The 16-QAM design is transmitted using Pseudo Random Binary Sequence (PRBS) and modulated by changeable clock frequencies. The Vedic multiplier uses Urdhva Tiryakbhyam (Vertical and Crosswise) method of multiplication to reduce the undesirable steps and generates parallel partial products. Compressor adders are used in the Vedic multipliers, which helps to increase the speed of multiplication process and reduces the carry delay. Four Compressor adders namely 5-3, 10-4, 15-4 and 20-5 are used in a 16-bit Urdhva Tiryakbhyam Vedic multiplier to add its partial products. The proposed 16-QAM design is implemented using Spartan-3 XC3S200-5 pq208 Field Programmable Gate Array (FPGA) device which occupies 672 slices, 1102 4-input Look up Tables (LUTs) and 39 mW of power consumption. The Vedic multiplier based 16-QAM transceiver design reduces 17.2% slices and 4.5% 4-input LUTs. The 16-QAM is a preferred digital modulation method in the Orthogonal Frequency Division Multiplexing (OFDM) system, which reduces bit errors and noise effects during data transmission. The OFDM transceiver design is used in the high-speed wireless communication by excellence of its Multi-carrier modulation method.

Disturbance and Signal Filter for Power Line Communication

Today, to use home automation, intelligent home controls or remote controls in the office, electronic equipment is moving away from wireless communication in favor of Power Line Communication (PLC). In the standard PLC solutions, the corrections that result from error transmissions are based on complex digital modulation methods and algorithms for validating the transmitted data without paying attention to the causes of the errors. This article focuses on the implementation of a filtering system for interference and signals in the 120–150 kHz band (CENELEC band C), which is injected into the network by transmitters. Such a filter separates the desired signal from the interference that is occurring in the network, which can result in communication errors. Moreover, when used properly, the filter can be used as a subsystem separation element. The paper presents the requirements, design, construction, simulation and test results that were obtained under actual operating conditions. It is possible to use less complex methods for correcting errors in transmission signals and to guarantee an improvement in the transmission rate using the proposed filter system.

Key Technologies and Applications of Gas Drainage in Underground Coal Mine

It is the basis for the long-drilling directional drilling, precise control of the drilling trajectory and ensuring the effective extension of the drilling trajectory in the target layer. The technology can be used to complete the multi-branch hole construction and increase the effective extraction distance of the coal seam. The gas drainage and the bottom grouting reinforcement in the advanced area are realized, and the geological structure of the coal seam can be proved accurately. It is the main technical scheme for the efficient drainage of gas at home and abroad, and it is applied to the field of geological structure exploration and water exploration and other areas. At present, the data transmission method is relatively mature in the technology and application, including the mud pulse and the electromagnetic wave. Compared with the mud pulse transmission mode, the electromagnetic wave transmission mode has obvious potential in the data transmission rate and drilling fluid, and it is suitable for the coal mine. In this paper, the key technologies of the electromagnetic wave transmission mode are analyzed, including the attenuation characteristics of the electromagnetic transmission channel, the digital modulation scheme, the channel coding method and the weak signal processing technology. A coal mine under the electromagnetic wave drilling prototype is developed, and the ground transmission experiments and down hole transmission test are carried out. The main work includes the following aspects. First, the equivalent transmission line method is used to establish the electromagnetic transmission channel model of coal mine drilling while drilling, and the attenuation of the electromagnetic signal is measured when the electromagnetic channel measured. Second, the coal mine EM-MWD digital modulation method is developed. Third, the optimal linear block code which suitable for EM-MWD communication channel in coal mine is proposed. Fourth, the noise characteristics of well near horizontal directional drilling are analyzed, and the multi-stage filter method is proposed to suppress the natural potential and strong frequency interference signal. And the weak electromagnetic communication signal is extracted from the received signal. Finally, the detailed design of the electromagnetic wave while drilling is given.

PROPOSING ENHANCED NA GAUN TECHNIQUE (ENGT) FOR RESOURCE BLOCK ALLOCATION IN LTE(LONG TERM EVOLUTION) SYSTEMS FOR IMPROVING QUALITY OF SERVICE

Due to its distinct and unique features viz. high speed data rate, self-organized network, packet optimized radio access, low latency and flexible bandwidth deployment LTE (Long Term Evolution) is more preferred in wireless communication. Such kind of terminology uses especially in mobile phones for improving its throughput. LTE uses Orthogonal Frequency Division Multiplexing (OFDM) for the downlink - that is, from base station to the terminal to transmit the data over many narrow band carriers each of 180 KHz instead of spreading one signal over the complete 5MHz career bandwidth. The complete working of LTE is based on the basic principle of OFDMA (Orthogonal Frequency Division Multiplexing). At first step, it divides the broad spectrum into multiple narrow bands and transmits information on this narrow channel in parallel.OFDM meets the LTE requirement for spectrum flexibility and enables cost-efficient solutions for very wide carriers with high peak rates.Orthogonal frequency-division multiplexing (OFDM), is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. Scheduling plays a vital role on the time of resource allocation which has become an essential component for high- speed wireless data systems. This allocation of resources is done according to the need and priority of the user. It has three key components which are involved in the resource allocation and network optimization: resource block scheduling, power control, and client association. The motive to design this new designed methodology is to increase its privacy rate by increasing its security level that automatically improves its speed and data rate. LTE uses OFDM (orthogonal frequency division multiplexing) for downlink transmission. In resource allocation algorithms in OFDM of LTE systems, the allocation of the radio resource has to be in the units of Scheduling Block (SB) and there exists the need for all SBs of each user to use the same Modulation and Coding Scheme (MCS) leading to the degradation of performance. Main challenge for LTE systems is that, by applying OFDMA, multiple resource blocks can be scheduled by a transmission over the frequency and time. In this research paper, we have to focus on resource block scheduling in LTE system and proposes an enhanced version of Na Gaun technique that would be helpful for resource allocation blocks so that user’s rate requirement can be fulfilled optimally and throughput of the system can be improved.

FPGA based digital phase-coding quantum key distribution system

Quantum key distribution (QKD) is a technology with the potential capability to achieve information-theoretic security. Phasecoding is an important approach to develop practical QKD systems in fiber channel. In order to improve the phase-coding modulation rate, we proposed a new digital-modulation method in this paper and constructed a compact and robust prototype of QKD system using currently available components in our lab to demonstrate the effectiveness of the method. The system was deployed in laboratory environment over a 50 km fiber and continuously operated during 87 h without manual interaction. The quantum bit error rate (QBER) of the system was stable with an average value of 3.22% and the secure key generation rate is 8.91 kbps. Although the modulation rate of the photon in the demo system was only 200 MHz, which was limited by the Faraday- Michelson interferometer (FMI) structure, the proposed method and the field programmable gate array (FPGA) based electronics scheme have a great potential for high speed QKD systems with Giga-bits/second modulation rate.