Transmission Link Research Articles

Performance enhancement of high-speed free space optical transmission link for the implementation of 5G and internet of things

Performance enhancement of high-speed free space optical transmission link for the implementation of 5G and internet of things

Bartonella quintana Infection in Kidney Transplant Recipients from Donor Experiencing Homelessness, United States, 2022.

Bartonella quintana infection can cause severe disease that includes clinical manifestations such as endocarditis, chronic bacteremia, and vasoproliferative lesions of the skin and viscera. B. quintana bacteria is transmitted by the human body louse (Pediculus humanus corporis) and is associated with homelessness and limited access to hygienic services. We report B. quintana infection in 2 kidney transplant recipients in the United States from an organ donor who was experiencing homelessness. One infection manifested atypically, and the other was minimally symptomatic; with rapid detection, both recipients received timely treatment and recovered. B. quintana was identified retrospectively in an archived donor hematoma specimen, confirming the transmission link. Information about the organ donor's housing status was critical to this investigation. Evaluation for B. quintana infection should be considered for solid organ transplant recipients who receive organs from donors with a history of homelessness or of body lice infestation.

The influence of atmospheric turbulence-induced optical intensity scintillation on the accuracy of satellite-to-ground laser one-way timing

This paper elucidates the mechanism by which atmospheric turbulence leads to errors in satellite-to-ground laser one-way timing, investigates the influence of optical intensity scintillation on the time delay jitter of laser signal arrival in single-satellite-to-ground transmission link. Furthermore, the impact patterns and the magnitude of atmospheric turbulence-induced one-way timing errors and positioning errors across various gradients of observation zenith angles in the GPS four-satellite-to-ground transmission link is also investigated. Besides, the study also explores the impact patterns and magnitude ranges of the effects of optical intensity scintillation on the four-satellite-to-ground time transfer system under different observed zenith angles with similar geometric dilution of precision (GDOP) conditions. The results show that smaller receiver zenith angles result in reduced errors caused by atmospheric turbulence-induced optical intensity scintillation, leading to higher accuracy in four-satellite positioning. When the GDOP factors range from 6.5 to 7.5, the timing errors for multiple sets of satellites consistently exhibit a normal distribution. Specifically, the four-satellite-to-ground laser one-way time transfer deviation averages around 2 ns, with jitter remaining within 1 ns.

100 Gb/s/λ polarization multiplexing PON downlink based on simplified heterodyne coherent reception

In this work, we experimentally demonstrate a 100Gb/s/λ downstream transmission link for coherent passive optical networks (PONs) up to 50 km, achieving an optical power budget of 29 dB through polarization multiplexing (PolMux) of two 50 Gb/s channels using multiband carrierless amplitude phase modulation (multiCAP) and optical single side band (OSSB) modulation. Additionally, we introduce a separate PolMux 50 Gb/s link that presents an optical power budget of 38.7 dB. Both links have been achieved using a simplified polarization-demultiplexing heterodyne coherent receiver. The robustness of the system is experimentally evaluated by analyzing its response to various input states of polarization. The transmission has been accomplished using 10 GHz electrical bandwidth devices at both the transmission and receiving ends, thereby paving the way for low-cost 100G links suitable for applications such as PONs.

An 80 Gbps Integrated PDM‐OAM‐Enabled‐FSO Transmission for Implementing 5G Services Under Riyadh Weather Conditions

ABSTRACTThe surge in demand of high‐capacity wireless information transmission links has led to emergence of novel multiplexing techniques for free space optics (FSO) over the past few years. Two such important techniques are polarization division multiplexing (PDM) and orbital angular momentum (OAM) multiplexing. This article investigates the integration of PDM and OAM techniques in a FSO transmission system to enable 5G communication services in Riyadh City, Saudi Arabia. Four OAM beams () of 2‐polarization states of a single frequency laser beam are used to transport 10 Gbps data independently. A total of 80 Gbps net transmission rate is achieved. The visibility data for Riyadh city are collected from Saudi Meteorological Department and the attenuation coefficient is calculated using Kim, Kruse, and Al‐Naboulsi attenuation models. The performance of all the PDM‐OAM modulated signals is compared for the three‐attenuation models in terms of bit error rate, eye diagrams, and Q Factor of the signal at the receiver. The results show that using Kim and Kruse models, with attenuation of 0.62 and 0.64 dB/km, the maximum range of 3.8 km is achieved. This is, however, reduced to 2.4 km using Al‐Naboulsi model having attenuation of 2.03 dB/km with acceptable limits of Q Factor (∼6 dB) and BER (∼9).

Self-Adaptive Intermediate Resonator in a 3-Coil Inductive Link for Power and Data Transmission

Self-Adaptive Intermediate Resonator in a 3-Coil Inductive Link for Power and Data Transmission

Test study on the impact of high-speed signal transmission based on VPX connectors

Abstract In high-speed digital signal transmission, VPX connectors play a crucial role as an important link for blind plug interconnection, ensuring the quality of high signal transmission. For high-speed circuit signal transmission, in order to ensure the absolute equal length of high-speed signals and avoid crosstalk caused by high-speed signals, this paper proposes a testing method that establishes a high-speed signal transmission link by designing equal-length sector modules and backplane blind plug interconnection through VPX; By using a vector network analyzer to test relevant parameters, we will analyze the differential characteristic impedance of VPX connectors after engagement under different structural tolerances, and obtain the quality of high-speed signal transmission. This testing research method can effectively analyze the main influencing factors of high-speed signal transmission in VPX connectors, and the research results provide effective support for engineering applications.

Cognitive learning enabled agile optical network

Nonlinear equalization (NLE) is essential for guaranteeing the performance of an optical network (ON). Effective NLE implementation relies on key parameters of the transmission link, including the modulation format (MF) and the launch power. As ONs become more agile, the parameters of fiber optical transmission need to be adaptive and relevant to the routing condition. Therefore, successful NLE implementation relies on the realization of transmission awareness (TA). Although machine learning-enabled optical performance monitoring (OPM) has been extensively investigated in the past few years, current NLE algorithms cannot autonomously perceive transmission parameters. Furthermore, current TA implementation still needs human intervention to guide the NLE. In addition, existing ML-based OPM and NLE cannot be trained autonomously, leading to the incapability of environmental change and mislabeling. Here, we propose cognitive learning (CL) for TA-guided NLE in agile ONs. We perform an experiment involving 32 Gbaud polarization-division-multiplexed (PDM)-quadrature phase shift keying (QPSK)/16-quadrature amplitude modulation (QAM) transmission over 1500 km of standard single-mode fiber (SSMF) with a variable launch power from 0 to 3 dBm. When a deep neural network (DNN) with amplitude histograms (AHs) as inputs and one step per span-learned digital back-propagation (1stps-LDBP) are developed, the CL simultaneously enables both TA and NLE, with the capability of self-learning, mislabeling resistance, and dynamic adaptation. The proof-of-concept experimental results indicate that both the accuracy of TA and the Q-factor of PDM-16QAM can be improved by 34.8% and 0.84 dB, respectively, when the launch power is 3 dBm. Moreover, the accuracy of TA is enhanced by 35.3%, even when the used data has 30% mislabeling. Therefore, the CL framework can be customized to satisfy various NLE implementations, thereby supporting the adaptive transmission of agile ONs.

Bat-associated ticks as a potential link for vector-borne pathogen transmission between bats and other animals.

Potentially zoonotic pathogens have been previously detected in bat-associated ticks, but their role in disease transmission and their frequency of feeding on non-bat hosts is poorly known. We used molecular blood meal analysis to reveal feeding patterns of the bat-associated tick species Ixodes ariadnae, I. simplex, and I. vespertilionis collected from cave and mine walls in Central and Southeastern Europe. Vertebrate DNA, predominantly from bats, was detected in 43.5% of the samples (70 of 161 ticks) but in these ticks we also detected the DNA of non-chiropteran hosts, such as dog, Canis lupus familiaris, wild boar, Sus scrofa, and horse, Equus caballus, suggesting that bat-associated ticks may exhibit a much broader host range than previously thought, including domestic and wild mammals. Furthermore, we detected the zoonotic bacteria Neoehrlichia mikurensis in bat ticks for the first time, and other bacteria, such as Bartonella and Wolbachia. In the light of these findings, the role of bat ticks as disease vectors should be urgently re-evaluated in more diverse host systems, as they may contribute to pathogen transmission between bats and non-chiropteran hosts.

Demodulating Optical Wireless Communication of FBG Sensing with Turbulence-Caused Noise by Stacked Denoising Autoencoders and the Deep Belief Network

Free-space optics communication (FSO) can be used as a transmission medium for fiber optic sensing signals to make fiber optic sensing easier to implement; however, interference with the sensing signals caused by the optical turbulence and scattering of airborne particles in the FSO path is a potential problem. This work aims to deep denoise sensed signals from fiber Bragg grating (FBG) sensors based on FSO link transmission using advanced denoising deep learning techniques, such as stacked denoising autoencoders (SDAE). Furthermore, it will demodulate the sensed wavelength of FBGs by applying the deep belief network (DBN) technique. This is the first time the real FBG sensing experiment has utilized the actual noise interference caused by the environmental turbulence from an FSO link rather than adding noise through numerical processing. Consequently, the spectrum of the FBG sensors is clearly modulated by the noise and the issue with peak power variation. This complicates the determination of the center wavelengths of multiple stacked FBG spectra, requiring the use of machine learning techniques to predict these wavelengths. The results indicate that SDAE is efficient in denoising from the FBG spectrum, and DBN is effective in demodulating the central wavelength of the overlapped FBG spectrum. Thus, it is beneficial to implement an FSO link-based FBG sensing system in adverse weather conditions or atmospheric turbulence.

Enhancing the efficiency of wavelength-shift fiber-based detectors for optical wireless communications

A wavelength-shift fiber-based optical detector promises to revolutionize the deployment of optical wireless communication (OWC) due to its inherent advantages over traditional receivers. These advantages include a flexible structure, a wide field of view (FOV), and a large active area. Despite progress in previous studies, there remains a gap in optimizing the re-utilization of unabsorbed light within wavelength-shift fiber (WSF) and maximizing the efficiency of light focusing onto photodetectors. To address these challenges, this study explores three novel, to the best of our knowledge, approaches to enhance the light conversion and detection efficiency of WSF-based optical detectors. First, a reflective mirror is employed behind the WSF array to increase the light absorption and re-emission probability. Second, a reflective mirror is placed at one end of the WSF array to direct the light toward the opposite end. Third, a tightly bundled WSF array configuration focuses the emitted light onto the photodetector’s active area. Experimental results demonstrate that each approach significantly improves the peak-to-peak voltage. This work presents an optical detector design featuring a large active area of 0.4cm×20cm, based on a blue-to-green color-converting WSF and achieving a high 3-dB bandwidth of up to 48 MHz. This design enables real-time data transmission at rates of 275 Mbps using non-return-to-zero on-off keying (NRZ-OOK) modulation over a distance of 1 m. Additionally, the transmission link operates at over 250 Mbps, with bit error rates (BERs) below the forward error correction (FEC) limit, under a wide FOV of 60°. This work opens exciting possibilities for revolutionizing photodetection schemes in non-line-of-sight free-space optical communications.

Design and Optimization of Direct-Drive Drilling Permanent Magnet Synchronous Motor

Abstract A direct-drive drilling electric drilling tool is developed due to the problems of long transmission link, low efficiency, and high failure rate of traditional electric drilling tools. In this paper, the key components of the direct-drive drilling permanent magnet synchronous motor (DPMSM) are designed and calculated, and the robust parameters optimization is performed by Taguchi method with efficiency and cogging torque as the optimization objectives. The air-gap length, thickness of permanent magnets, pole-arc coefficient, and width of slot top are selected as significant factors, and the impact of the optimized parameters on the efficiency and cogging torque of the DPMSM is calculated with orthogonal experiment to obtain the optimal combination of factors. Comparing the DPMSM’s performance before and after optimization, the cogging torque is reduced by 80.1% and the efficiency is improved by 0.24% after optimization. Finite element simulation of the electromagnetic characteristics of the optimized DPMSM under no-load and load conditions is carried out to verify the rationality of the optimization. Calculate the main losses of the DPMSM and the heat generation rate of key components. The analysis model of the DPMSM’s temperature field is established, and the temperature field simulation is carried out with and without drilling fluid respectively to further verify the rationality of the motor’s design. This work can promote the engineering application of downhole direct-drive electric drilling tools and provide technical support for the innovation of drilling equipments for marine energy.

Design of a triggerless readout electronics system for CDEX-50

Direct detection of light-mass dark matter is a frontier topic in international physics research. The reduction of system threshold is important in order to improve the sensitivity of light-mass dark matter detection. The scientific goal of the China Dark Matter Experiment (CDEX) at Jinping Underground Laboratory in China is to detect WIMPs utilizing a high-purity germanium array detector. CDEX-10 achieved the most sensitive results in the 4 to 5 GeV/c 2 range. CDEX-50 aims to achieve an energy threshold of 100 eV, which significantly increases data bandwidth and complicates the implementation of noise reduction algorithms, thereby posing challenges to the readout electronics system. In this paper, a triggerless readout electronics system based on FPGA-GPU is designed for CDEX-50, which can achieve full energy range detection from 100 eV to 10 MeV. A verification prototype of a triggerless electronics system utilizing a Broad Energy Germanium (BEGe) detector has been developed to test the performance of high-bandwidth transmission and data processing. The results demonstrate that the bit error rate for the high-speed transmission link of the triggerless readout electronics system is below 1015. Furthermore, the FPGA-GPU transmission bandwidth, utilizing P2P DMA, achieves 100.2 Gbps, and the mean filter implemented on the GPU is capable of processing a 64 Gbps data stream in real-time. These results provide foundation for the design of the triggerless readout electronics system for CDEX-50.

An Assessment of HF Radio Wave Propagation in Antarctica for a Radio Link Between McMurdo and South Pole Station

AbstractIn this work, we analyze data collected by an HF transmitter/receiver radio link, operating as an oblique ionosonde between the McMurdo Station (transmitter) and South Pole Station (receiver) at 4.1, 5.1, 6.0, 6.4, and 7.2 MHz between 28 February and 14 March 2019. To help contextualize the link's data we have performed numerical raytrace simulations to help understand the observations. By considering both the data and simulations, we have identified both single‐ and two‐hop E‐ and F‐region propagation modes in the data, where the multi‐hop modes were observed in the hours around sunrise and sunset in the 4.1 and 5.1 MHz channels. This is an unexpected result given the accepted wisdom that multi‐hop modes, which require a ground scatter component, cannot be supported in Antarctica because of the highly absorptive ice covering much of the continent. Our results show that multi‐hop propagation modes can be supported in the region under specific ionospheric conditions—around sunrise and sunset—if the mode's ground scatter component is collocated with the Transantarctic Mountains. The mountains are located along the great‐circle path between the link's transmitter and receiver. However, the combination of favorable ionospheric and ground scattering conditions makes the detection of the multi‐hop mode a rare occurrence in the data set analyzed here. These findings are critical to data analysis efforts of any current or future oblique ionosonde systems operating in Antarctica and other regions such as the Arctic.

Extending the design space of minimized VA rating inductive wireless power transfer links operating in restricted sub-resonant frequency region with constant current output

Wireless power transfer systems are typically required to operate under varying geometrical positioning (vertical distance, misalignment) between the transmitter and receiver coils while supporting a load with non-constant characteristics. This creates the need for robust systems that can operate over a range of coupling coefficients under time-varying load. Widespread control methods utilized to support such an operation typically suffer from volt-ampere (VA) over-rating of the inductive wireless power transfer link (IWPTL) transmitter. Sub-resonant frequency control has proven to be an effective solution to this problem, attaining robust operation and minimized transmitter VA rating by utilizing operational frequency as the control variable for system output regulation under above-mentioned constraints. However, allowed operating frequency range is usually restricted in practical applications (e.g. to 79 kHz–90 kHz by SAE J2954 EV charging standard), limiting the misalignment tolerance of sub-resonant control method. Recently, extension of the classical sub-resonant control methodology was proposed in order to overcome this limitation. However, no clear guidelines were given for designing practical IWPTLs operating under extended sub-resonant control. To this end, this work bridges the gap between academical findings and practical applications by establishing generalized guidelines for designing sub-resonant controlled series-series (SS) compensated IWPTL with minimized transmitter VA rating, allowing to maximize misalignment tolerance under given operating frequency and output voltage ranges. The proposed methodology is accurately validated by simulations and experiments, demonstrate close correlation with analytical predictions. Experimental framework reveals that IWPTL operating under extended sub-resonant control methodology attains 50 % increase of tolerable coupling coefficients range compared to a classical system designed to operate under sub-resonant control under identical operating conditions while achieving nearly similar DC-to-DC efficiency.

Multi-Path Data Transmission System Based on 5G Communication Technology

Due to the current problems of 5G(5th Generation Mobile Communication Technology) networks such as discontinuous coverage, poor coverage performance, and insufficient uplink rate, the real-time transmission performance of 5G networks has been greatly affected, and cannot meet the growing needs of high-speed communication and applications based on the Internet of Things. This paper aims to improve the transmission effect of 5G communication technology by improving the algorithm. By analyzing the problems of existing 5G bandwidth estimation algorithm, this paper proposes a Westwood-based coupling adaptive bandwidth estimation algorithm, and describes the algorithm ideas involved in the algorithm point-by-point. Moreover, this paper uses adaptive bandwidth estimation algorithm to update the slow start threshold in the fast retransmission phase, which makes the congestion window size of path transmission more reasonable. Simulation results show that the congestion control algorithm proposed in this paper improves the accuracy of link bandwidth estimation to a certain extent, improves the link congestion situation and improves the throughput of multipath transmission links. This article can be applied to the algorithm in multipath data transmission to further improve data processing efficiency and processing speed.Therefore, the improved method in this paper can be used in the practice of 5G communication to further improve the efficiency of 5G communication.

Research on Network Security and Privacy Protection Technology of Autonomous Vehicle

With the rapid development of information technology and the increasing maturity of intelligent transportation systems, autonomous vehicles, as an important carrier of future travel, are gradually moving from concept to commercial application. However, the highly connected and intelligent nature of autonomous vehicles also makes them face unprecedented cybersecurity and privacy protection challenges. This paper deeply discusses the security threats and privacy disclosure risks of autonomous vehicles in network architecture, data transmission, data processing and other links, and systematically reviews the current technical means and research progress to address these challenges. This paper Outlines the data collection and transmission mechanism of autonomous vehicles, including the collection and processing of sensor data as well as the communication process between vehicles and the cloud, other vehicles and transportation infrastructure, and analyzes in detail the network security threats faced by autonomous vehicles, including remote control attacks, malware attacks, communication hijacking, etc. These threats can lead to serious consequences such as vehicle failure, data breach, or system crash. At the same time, the paper also points out the challenges faced by autonomous vehicles in terms of privacy protection, such as the risk of leakage of sensitive data such as personal location information and driving habits, as well as the risk of data abuse and sharing. In order to address the above challenges, this paper focuses on the technical research progress of cybersecurity and privacy protection of autonomous vehicles. In the aspect of network security, this paper discusses the key technical means such as data encryption, access control, intrusion detection and response system, and emphasizes the importance of security hardware and software in improving the overall security of the system. In terms of privacy protection, this paper proposes strategies such as anonymization and desensitization technology, privacy protection protocols and standards to protect users' privacy from invasion.

Enabling high-speed and large-capacity data transmission in optical inter-satellite communication links under various conditions

Enabling high-speed and large-capacity data transmission in optical inter-satellite communication links under various conditions

A New Diffusion Strategy Using an Epidemic Spreading Model for Encryption.

The diffusion phenomenon that exhibits intrinsic similarities is pervasive in cryptography and natural systems, evident in liquid diffusion, epidemic spread, animal migration, and encryption techniques. In cryptography, bytes are systematically diffused in a sequential manner to encrypt the value of each byte in the plaintext in a linear fashion. In contrast, within an epidemic spreading model, the diffusion process can be represented within a complex, multilayered network, encompassing layers such as familial and social transmission dynamics. Transmission links establish connections both within and between individual layers. It has had a more rapid spread than linear approaches due to the particularization of non-linear transmission. In this study, the novelty of a cryptography diffusion strategy based on an epidemic model is first proposed, in which pixels and their dynamic adjacency are considered as vertices and edges, respectively, within a complex network framework. Subsequently, the encryption process is governed by the Susceptible-Vaccinated-Infected-Recovered (SVIR) model integrated with chaotic dynamics. Simulation results demonstrate that the proposed algorithm exhibits faster encryption speed while effectively resisting brute force, statistical, and differential attacks. Furthermore, it demonstrates strong robustness against noise interference and data loss.

Investigation of urban low-altitude long-range atmospheric links for FSO coherent communication

Due to the complexity of low-altitude atmospheric channel conditions, the commercial application of FSO communication systems is less prevalent than satellite applications. This is mainly because there is a trade-off between achieving system stability through active compensation technology and maintaining low costs. Different application scenarios and atmospheric channel states correspond to different optimal structural parameter selections, which is crucial for low-cost FSO systems without complex compensation mechanisms. Therefore, measuring actual channel conditions is essential. One existing issue is that current research does not sufficiently discuss the connection between theoretical analysis and practical experiments in FSO communication, thus, establishing models and analysis methods is necessary that can accurately predict the performance of actual FSO atmospheric communication systems. We have developed a comprehensive FSO model to evaluate the effects of channel and structural factors on system performance. This model is vital for cost-effective parameter selection in system design and for analyzing actual system performance. Additionally, we established 6.6 km and 12.7 km FSO transmission links in an urban low-altitude environment. Subsequently, we conducted tests on atmospheric attenuation, channel statistical characteristics, and DPSK/QPSK coherent communication performance. Based on the analysis that combines experiments with theory, we have deduced the atmospheric attenuation of FSO links. The channel statistical characteristics provided the statistical properties of the two links under weak, moderate, and strong turbulence, along with fitting curves. Long-term channel statistical experiments indicate that the channel is most stable during the early morning hours of the day, and the 12.7 km communication experiment without turbulence correction technology is only feasible at this time. Furthermore, we presented a method for using theory to evaluate the performance of actual FSO systems in random atmospheric channels.