High-speed Data Communication Research Articles

Reducing PAPR of OFDM signals using a tone reservation method based on ell_{infty }-norm minimization

Orthogonal frequency division multiplexing (OFDM) continues to be the most preferred signal-multiplexing scheme for high-speed data communication. However, OFDM signals are known to have the problem of high peak-to-average power ratio (PAPR), especially when the number of subcarriers is large, which leads to nonlinear amplification in the high power amplifier and consequently to bit-error rate degradation and out-of-band radiation. In this paper, we propose a new optimal tone reservation method for reducing high PAPR in OFDM signals in order to avoid nonlinear amplification effects. The method employs Chebyshev-norm minimization to determine peak-reduction coefficients for OFDM signal. Simulation results show that the proposed method can achieve high PAPR reduction at the expense of a small loss in data rate and a slight increase in average transmit power. For example, with 4 out of 64 subcarriers reserved for peak-reduction coefficients, which represents 6.25% data-rate loss, the method can achieve 4.06 dB of PAPR reduction with only a 0.46 dB increase in average transmit power. Similarly, when 8 subcarriers or 12.5% of the total number of subcarriers are reserved, a PAPR reduction of 5.75 dB is achieved with a paltry 0.19 dB rise in transmit power.

Design of Real-Time Digital Multi-Beamformer of Digital Array Antenna System for MFR

In this paper, we implement a digital multi-beamformer using FPGA(Field Programmable Gate Array) which has advantages in parallel and real-time data processing. This is accomplished through the use of not only high-speed data communication but also multiple beam forming, which is currently required by MFR(Multi Function Radar). As a result, the beamformer can process 24 Gbps throughput in real-time and form 5 digital beams at the same time. It is also compared to the results of Matlab simulations. We demonstrate how an implemented beamformer can be used in an MFR system by using a digital array antenna.

A 3D Modulation Scheme for High-speed Baseband Digital Communication System

To improve the transmission rate of wireless communications, the communication frequency band will gradually go higher, and the use of millimeter wave and terahertz will become mainstream in the future. However, the signal attenuation in high bands is considerable, which prevents the achievement of long-distance transmissions. In this paper, we propose a 3D modulation scheme that is especially suitable for high-speed baseband digital communication systems. The proposed scheme is simulated and tested in an experiment. With the same order of modulation, the 3D modulation shows a significant decrement in bit error rate and enables a longer transmission distance.

Microwave dielectric properties and thermal conductivities of low-temperature sintered (Na1-xKx)2MoO4 (x ≤ 0.2) ceramics

The Mo-based glass-free spinel-type structure of the (Na1-xKx)2MoO4 (x = 0.0, 0.1, and 0.2) ceramic series was prepared using the traditional solid-state method at the low sintering temperature (<650 °C). The microwave dielectric properties of the (Na1-xKx)2MoO4 series were determined in terms of phase compositions, crystal structure (via XRD), and microstructure analysis (via FE-SEM and EDS). The results revealed that the double-phase (cubic and orthorhombic) formation plays a significant role in the entire (Na1-xKx)2MoO4 series. It exhibits excellent dielectric properties: dielectric constant εr = 4 (1 GHz)/3.77 (15 GHz), tangent loss tan δ = 8.3 × 10−2 (1 GHz)/7 × 10−3 (15 GHz; Q × f = 2143 GHz), temperature coefficient of frequency (TCF) τf = −6.45 ppm/°C, and room temperature thermal conductivity (κ) = 1.76 W/(m.K) for x = 0.1 at a sintering temperature of 575 °C. These make the (Na1-xKx)2MoO4 ceramic series a potential candidate for low-temperature co-fired ceramic (LTCC) substrate applications (as used in antennas) for high-speed data communications.

Deep Q-Learning-Based Transmission Power Control of a High Altitude Platform Station with Spectrum Sharing.

A High Altitude Platform Station (HAPS) can facilitate high-speed data communication over wide areas using high-power line-of-sight communication; however, it can significantly interfere with existing systems. Given spectrum sharing with existing systems, the HAPS transmission power must be adjusted to satisfy the interference requirement for incumbent protection. However, excessive transmission power reduction can lead to severe degradation of the HAPS coverage. To solve this problem, we propose a multi-agent Deep Q-learning (DQL)-based transmission power control algorithm to minimize the outage probability of the HAPS downlink while satisfying the interference requirement of an interfered system. In addition, a double DQL (DDQL) is developed to prevent the potential risk of action-value overestimation from the DQL. With a proper state, reward, and training process, all agents cooperatively learn a power control policy for achieving a near-optimal solution. The proposed DQL power control algorithm performs equal or close to the optimal exhaustive search algorithm for varying positions of the interfered system. The proposed DQL and DDQL power control yields the same performance, which indicates that the actional value overestimation does not adversely affect the quality of the learned policy.

Control of polarization switching in a VCSEL via resonant feedback from a whispering-gallery-mode cavity.

We report a method for flexibly switching the dominant polarization of a vertical-cavity surface-emitting laser (VCSEL) by introducing polarization-resolved resonant optical feedback from a whispering-gallery-mode (WGM) cavity to the lasing cavity. Switching between the originally dominant mode and a side mode is experimentally demonstrated under different bias currents once one of them is locked to the resonance mode of the WGM cavity. In addition to a controllable polarization state, the reported VCSEL also demonstrates a linewidth as narrow as tens of kilohertz, which is highly desirable for many applications, including high-speed data communication, light detection and ranging (lidar), and absorption spectroscopy.

Top-emitting 940-nm thin-film VCSELs transferred onto aluminum heatsinks

Thin-film vertical cavity surface emitting lasers (VCSELs) mounted onto heatsinks open up the way toward low-power consumption and high-power operation, enabling them to be widely used for energy saving high-speed optical data communication and three-dimensional sensor applications. There are two conventional VCSEL polarity structures: p-on-n and n-on-p polarity. The former is more preferably used owing to the reduced series resistance of n-type bottom distributed Bragg reflection (DBR) as well as the lower defect densities of n-type GaAs substrates. In this study, the p-on-n structures of thin-film VCSELs, including an etch stop layer and a highly n-doped GaAs ohmic layer, were epitaxially grown in upright order by using low-pressure metalorganic chemical vapor deposition (LP-MOCVD). The p-on-n structures of thin-film VCSELs were transferred onto an aluminum heatsink via a double-transfer technique, allowing the top-emitting thin-film VCSELs to keep the p-on-n polarity with the removal of the GaAs substrate. The threshold current (Ith) and voltage (Vth) of the fabricated top-emitting thin-film VCSELs were 1 mA and 2.8 V, respectively. The optical power was 7.7 mW at a rollover point of 16.1 mA.

Research on long distance submarine optical fiber transmission system using MSK downlink signals

The commonly used submarine optical fiber communication system is expected to provide long-distance reliable signals transmission. We present a novel optical fiber submarine system using minimum shift keying (MSK) encoded downstream signals. 10Gb/s MSK coded signals are successfully transmitted over the 100km submarine single-mode fiber (SMF).The optical spectrums, eye-diagrams and bit error rate (BER) before and after transmission of MSK signals in the system were measured and analyzed. The results show that, compared with conventional access methods, this scheme can provide high-speed, stable and secure data communication.

An optical access scheme with 1.25Gbit/s NRZ downstream signals over 6GHz subcarrier for next generation mobile systems application

In order to solve the problem of network frequency resource congestion from the central office (CS) to the base station (BS) in sixth generation (6G) mobile communication systems, we design a passive optical network (PON) access scheme. 1.25Gbit/s non-return-to-zero (NRZ) downstream signals over 6GHz subcarrier are successfully transmitted in the 20km single-mode fiber (SMF) and allocated to 4 optical network units (ONUs). The radio frequency (RF) spectrums, optical spectrums, eye-diagrams and bit error rate (BER) before and after transmission of NRZ signals in the system were measured and analysed. The results show that, this scheme can provide high-speed, stable and secure data communication.

Design and Implementation of Power-Efficient FSM based UART

The remarkable innovations in technology are driven mainly by the high-speed data communication requirements of the modern generation. The Universal Asynchronous Receiver Transmitter (UART) is one of the most sought-after communication protocols. This work mainly focuses on implementing and analysing the UART for data communication. The Finite State Machine (FSM) implements the baud rate generator, transmitter, and receiver modules. Cadence NCSIM was utilized for simulation, and Cadence RTL Compiler was used during synthesis using the 45 nm and 90 nm General Process Design Kit (GPDK) library files. The baud rate of 9600 bps and 50 MHz clock frequency was used to design UART. The increased speed and complexity of the VLSI chip designs has resulted in a significant increase in power consumption. The comparative analysis of power and delay for different clock periods shows an improvement in the total power and the Power Delay Product (PDP) with increasing clock periods. Better results were observed using 45 nm in comparison to the 90 nm library.

A Brief Review of Path Loss Models for mmWave Channels

It is planned to use millimeter wave (mm-wave) communication in 5th Generation (5G) communication systems, as it allows high bandwidth and accordingly high speed data communication. Path loss is one of the most important factors affecting system performance in mm-wave communication. Therefore, path loss must be taken into account in order to create an efficient and reliable mm-wave communication system and to obtain high data rates. It is very important for 5G systems to accurately determine the propagation characteristics and path loss models of the mm-wave communication channel. Many methods have been proposed in the literature to predict path loss with high accuracy and precision in 5G systems. In this review, it is aimed to provide researchers a clear knowledge about path loss in 5G mm-wave communication systems. Papers published between 2018-2021 which based on machine learning, deep learning, neural networks and propagation measurement approach were presented, and the main results of researches related to main path loss models Close-in (CI), and Alpha, Beta, Gamma (ABG) or Floating Intercept (FI) and papers that discussed 3-D ray tracing method were summarized in clear and precise manner.

Estimation of Phase Noise Transfer Function

Quantifying frequency converters’ residual phase noise is essential in various applications, including radar systems, high-speed digital communication, or particle accelerators. Multi-input signal source analyzers can perform such measurements out of the box, but the high cost limits their accessibility. Based on an analysis of phase noise transmission theory and the capabilities of popular instrumentation, we propose a technique extending the functionality of single-input devices. The method supplements absolute noise measurements with estimates of the phase noise transfer function (also called the jitter transfer function), allowing the calculation of residual noise. The details of the hardware setup used for the method verification are presented. The injection of single-tone and pseudo-random modulations to the test signal is examined. Optional employment of a spectrum analyzer can reduce the time and number of data needed for characterization. A wideband synthesizer with an integrated voltage-controlled oscillator was investigated using the method. The estimated transfer function matches a white-box model based on synthesizer’s structure and values of loop components. The first results confirm the validity of the proposed technique.

Communication Technologies for Smart Grid: A Comprehensive Survey.

With the ongoing trends in the energy sector such as vehicular electrification and renewable energy, the Smart Grid (SG) is clearly playing a more and more important role in the electric power system industry. One essential feature of the SG is the information flow over high-speed, reliable, and secure data communication networks in order to manage the complex power systems effectively and intelligently. SGs utilize bidirectional communication to function whereas traditional power grids mainly only use one-way communication. The communication requirements and suitable techniques differ depending on the specific environment and scenario. In this paper, we provide a comprehensive and up-to-date survey on the communication technologies used in the SG, including the communication requirements, physical layer technologies, network architectures, and research challenges. This survey aims to help the readers identify the potential research problems in the continued research on the topic of SG communications.

Ultrafast 2 × 2 green micro-LED array for optical wireless communication beyond 5 Gbit/s

A green 2 × 2 micro light-emitting diode ( μ - LED ) array with nanostructured grating patterns grown on a semipolar (20-21)-oriented gallium nitride (GaN) buffered layer on (22-43)-oriented sapphire substrate is specially transistor-outline can (TO-can) packaged with a sub-miniature-A (SMA) connector for high-speed data communication beyond 5 Gbit/s. Through a specific design for suppressing the quantum-confined Stark effect (QCSE) in the green 2 × 2 μ - LED array with a low polarization-related electric field and flat quantum well band diagram, the green 2 × 2 μ - LED array exhibits a turn-on voltage of 2.5 V and output power of 0.3 mW at 1 A / cm 2 . The green 2 × 2 μ - LED array also reveals a wavelength shift from 543 nm to 537 nm smaller than that of conventional devices grown on c -plane buffered GaN substrate due to the inhibited QCSE. The 50 µm emission aperture of the green 2 × 2 μ - LED array ensures a lower capacitance for a larger − 3 dB modulation bandwidth, which exhibits − 1 dB power compression at a larger bias under high-speed operation, as it is less affected by the high resistance of the single μ - LED element. With a specific TO-can+SMA package, the green 2 × 2 μ - LED array exhibits maximal data rates exceeding 1.5 Gbit/s for the non-return-to-zero on–off keying format and beyond 5.02 Gbit/s for the bit-loaded discrete multitone (BL-DMT) format, which is very promising for optical wireless communication. As the sampling rate increases from 4 GSa/s to 16 GSa/s, the μ - LED array’s received signal-to-noise ratio (SNR) improves dramatically from 15.4 dB to 12.2 dB. The SNR remains about 15.4 dB, with a matching bit-error ratio (BER) of 2.7 × 10 − 3 , whereas the 10-fold oversampling of the eight-ray quadrature amplitude modulation orthogonal frequency-division multiplexing (8-QAM OFDM) data stream with 16 GSa/s appears to reduce the SNR by − 3 dB , resulting in a decoded BER of 3.3 × 10 − 3 . The green 2 × 2 μ - LED array has demonstrated greater potential in data transmission beyond 5 Gbit/s using the BL-DMT algorithm for future applications in domains of visible light communication or optical wireless communication when packaged with handed mobile devices.

Using IoT devices for fast data processing

IoT systems make a significant contribution to the growth of global traffic. There is a trend to reduce the volume of transmitted and stored data, for which different approaches are used. Most approaches use traditional data processing in the Cloud and at the gate level. The end devices are not involved to the data processing. The article describes the correlation method of data processing on the end device. The results of a research of the maximum performance when implemented on an FPGA, with different number of taps of the matched filter and different bit width of the input data stream are presented. This method allows to work with high-speed data streams and communication channels typical for IoT systems. The boundary conditions of operability for the correlation method are given. On the basis of the presented model of the IoT system, data processing delays for the correlation method and the method using data processing on the gate application of IoT devices for fast data processing are analyzed.

Emerging light-emitting diodes for next-generation data communications

The continuing development of consumer electronics, mobile communications and advanced computing technologies has led to a rapid growth in data traffic, creating challenges for the communications industry. Light-emitting diode (LED)-based communication links are of potential use in both free space and optical interconnect applications, and LEDs based on emerging semiconductor materials, which can offer tunable optoelectronics properties and solution-processable manufacturing, are of particular interest in the development of next-generation data communications. Here we review the development of emerging LED materials—organic semiconductors, colloidal quantum dots and metal halide perovskites—for use in optical communications. We examine efforts to improve the modulation performance and device efficiency of these LEDs, and consider potential applications in on-chip interconnects and light fidelity (Li-Fi). We also explore the challenges that exist in developing practical high-speed LED-based data communication systems. This Review examines the development of emerging semiconductor materials—organic semiconductors, colloidal quantum dots and metal halide perovskites—for light-emitting diodes, considering efforts to improve modulation performance and device efficiency, as well as potential applications in on-chip interconnects and light fidelity (Li-Fi).

Design of Novel Optical Fiber Communication Electronic System and Big Data Prediction Method of Its Loss

For the shortcomings of traditional data communication electronic mode and bus interface, optical fiber communication electronic technology and compact peripheral component interconnect (CPCI) bus interface mode with industry standard are adopted to design a kind of optical fiber communication electronic data transmission mode. The optical fiber communication electronic board based on CPCI bus constitutes a novel optical fiber communication electronic system. In the process of hardware design, the small form-factor pluggable (SFP) transceiver module is used to convert the photoelectric signal and complete the transmission of optical fiber data. Regarding the existence of differential signal in high-speed serial circuit of electronic board, the wiring is reasonably arranged. The hardware test platform of optical fiber communication electronic system is built based on PCI9054 CPCI bus and industrial personal computer (IPC) communication electronics. FPGA with embedded high-speed serial transceiver module is adopted to design the hardware logic function. Binary gray code is used to count. FIFO protocol and Aurora protocol are supported. Protocol IP core is customized to realize the full duplex electronic communication of high-speed data. Considering the loss problem of the system, the grey model GM(1, 1), ARIMA model and Elman neural network are employed as the big data level research scheme, which are combined into the loss prediction model according to a certain proportion. In the experiment, the test of DMA data reading and writing function is designed, and the embedded highspeed transceiver module and optical fiber communication electronic logic function are simulated. The results show that the symbol error rate (SER) is always 0, and the low-pass filtering characteristics of the channel are effectively compensated, which makes the signal quality stabler. Compared with the single big data level research scheme, the combined model has smaller prediction error and higher prediction accuracy.

Final Finishing for High Speed Data Communication

Final Finishing for High Speed Data Communication

Dynamic Route Discovery Using Modified Grasshopper Optimization Algorithm in Wireless Ad-Hoc Visible Light Communication Network

In recent times, visible light communication is an emerging technology that supports high speed data communication for wireless communication systems. However, the performance of the visible light communication system is impaired by inter symbol interference, the time dispersive nature of the channel, and nonlinear features of the light emitting diode that significantly reduces the bit error rate performance. To address these problems, many environments offer a rich infrastructure of light sources for end-to-end communication. In this research paper, an effective routing protocol named the modified grasshopper optimization algorithm is proposed to reduce communication interruptions, and to provide alternative routes in the network without the need of previous topology knowledge. In this research paper, the proposed routing protocol is implemented and analyzed using the MATLAB environment. The experimental result showed that the proposed routing protocol adapts to dynamic changes in the communication networks, like obstacles and shadows. Hence, the proposed protocol achieved better performance in data transmission in terms of throughput, packet delivery ratio, end-to-end delay, and routing overhead. In addition, the performance is analyzed by varying the number of nodes like 50, 100, 250, and 500. From the experimental analysis, the proposed routing protocol achieved maximum of 16.69% and minimum of 2.20% improvement in packet delivery ratio, and minimized 0.80 milliseconds of end-to-end delay compared to the existing optimization algorithms.

A 4GS/s 8‐bit time‐interleaved SAR ADC with an energy‐efficient architecture in 130 nm CMOS

AbstractThis paper presents the design, implementation, and measurements of a 4 GS/s, 8‐bit resolution, time‐interleaved (TI) analog‐to‐digital converter (ADC) comprised of 32 asynchronous successive approximation register (SAR) ADCs. The chip is fabricated in a 130 nm CMOS process. This prototype achieves the highest sampling rate and the best efficiency for a SAR TI‐ADC in the process used. An energy‐efficient hierarchical T&amp;H architecture, ranked in a 4 × 8 structure, has been used to interleave the aforementioned high number of SAR ADCs avoiding the power hungry buffers typically used in the input signal path and/or T&amp;H outputs. The sampling architecture includes programmable delay cells with up to 104 fs resolution to calibrate sampling time errors. Additionally, the input matching network uses an on‐chip inductance to mitigate the impact of the packaging on the analog bandwidth. An efficient SAR ADC implementation is achieved by an optimized comparator design, which allows for both, noise and asynchronous clock control, and includes background DC offset calibration. The test chip is the core of a measurement platform dedicated to the evaluation of mismatch calibration techniques for ADCs used in high speed digital communication systems. To enable this application, a 32Gb/s low‐voltage differential signaling interface is included to transmit the samples off‐chip without any decimation. The TI‐ADC achieves a peak 7.09 effective number of bits (ENOB) (5.47ENOB at Nyquist) and 1.3 GHz input bandwidth with a power consumption of 93 mW at 1.2 V. Each SAR ADC channel achieves a Walden figure of merit (FOM) of 123fJ/conv‐step and owing to the efficient interleaved architecture the full TI‐ADC achieves a peak FOM of 171fJ/conv‐step (526fJ/conv‐step at Nyquist).