Performance Of Communication Systems Research Articles

The analysis of the non-Kolmogorov turbulence effect on the performance of uplink coherent DPSK laser satellite communication system in the presence of tilt-corrected beam wander

AbstractIn the present study, a model for analyzing the performance of laser-based satellite uplinks that account for beam wander and atmospheric turbulence is presented. The developed scintillation index model is a continuation of the recent works considering the effects of non-Kolmogorov turbulence on the propagation of Gaussian beams across turbulent media. We specifically concentrate on the specific regime under the tilt-corrected beam wander. The on-axis scintillation index is developed assuming an isotropic non-Kolmogorov spectrum model where the power law exponent (PLE) effective value, $$\alpha$$ α , is taken to be 3 < $$\alpha$$ α < 4. Within that regime, effective irradiance models for tilt-corrected beam wander are presented, using the Gamma and Gamma-Gamma distributions. Closed-form expressions of the average bit error rate (BER) are derived to evaluate the performance of the optical communication system considering coherent detection of differential phase shift keying. The obtained numerical results show the impact of the Gaussian beam radius at the transmitter, the PLE effective value, and the zenith angle on the on-axis scintillation index and the average BER of the system under consideration. Due to beam wander, the link performance in terms of scintillation index and average BER depends on the beam radius at the transmitter. With tilt-corrected beam wander the link performance becomes best at an intermediate value of beam radius. With the non-Kolmogorov turbulent medium model, the PLE effective value has a major effect on the beam radius with the best performance. The obtained results guide the choice of the optimum beam radius for best performance for each PLE effective value.

Vortex inverted pin beams: mitigation of scintillations in strong atmospheric turbulence.

We recently introduced a new class of optical beams with a Bessel-like transverse profile and increasing beam width during propagation, akin to an "inverted pin." Owing to their specially engineered distribution, these beams have shown remarkable performance in atmospheric turbulence. Specifically, inverted pin beams (PBs) were found to have a reduced scintillation index as compared to collimated or focused Gaussian beams as well as other types of pin beams especially in moderate to strong turbulence. In this work, we demonstrate that inverted pin beams carrying orbital angular momentum (OAM) can further suppress intensity scintillations in moderate to strong irradiance fluctuation conditions. Our results can be useful in improving the performance and link availability of free-space optical communication systems.

Simulative analysis of carrier suppressed return to zero based symmetrical compensated optical link

Abstract Optical communication systems provide high data rates to fulfil users’ demands. In addition, the modulation format is essential to the system’s transmission quality and spectral efficiency. Furthermore, the effects of chromatic dispersion, which impair the performance and quality of transmitted signals, are mitigated using dispersion compensation techniques. In optical communication systems, dispersion compensation techniques are essential for preserving signal quality, increasing transmission distances, improving system performance, and offering network designers flexibility. These methods seek to improve signal quality and enable transmission at longer distances by reducing or eliminating the distortion brought on by dispersion. This paper uses a symmetrical compensation technique to analyze the performance of the CSRZ modulation format-based optical communication system. The research is conducted within a communication range of 150–350 km. The system is evaluated in terms of input power, filter order, and filter depth. The results indicate that the proposed system performed better at an input power of 4 dBm using a third-order filter and 60 dB filter depth.

Experimental Study on Transmission Performance of Ultraviolet and Visible light Communication System under Artificial Fog Channel

Experimental Study on Transmission Performance of Ultraviolet and Visible light Communication System under Artificial Fog Channel

Solar Wind‐Magnetosphere Coupling Efficiency and Its Dependence on Solar Activity During Geomagnetic Storms of 23–24 Solar Cycles

AbstractSpace weather forecasts are of utmost importance in safeguarding navigation, communication, and electric power system operations, satellites from orbital drag, and the astronauts in the International Space Station from hazardous space radiation during extreme space weather conditions. The finest space weather prediction requires a clear understanding of solar wind‐magnetosphere coupling. The in‐situ measurements of the solar wind properties give unique information about the Sun and its activity on smaller to longer timescales. The present work investigates the influence of solar activity on the coupling of solar wind and Earth's magnetosphere during 23–24 solar cycles. The geomagnetic storms with Symmetric H‐component (SYMH) ≤ −85 nT during the 23–24 solar cycles are considered. We present the results of statistical analysis and relationships between the various solar wind parameters such as the total strength of interplanetary magnetic field (B) and its three‐axis components (Bx, By, and Bz), solar wind proton density (Nsw), solar wind speed (Vsw), SYMH indices, the amplitude, duration, and profile of the geomagnetic storms. The integrated electric field and integrated SYMH index during storms show the highest correlation of 0.92, implying that integrated SYMH is a better proxy of the injected solar wind energy in the magnetosphere in the form of the ring current. Moreover, we do see the difference in the solar wind‐magnetosphere coupling efficiency during the phases of 23–24 solar cycles which is intriguing.

Quantum communications for image transmission over error‐prone channels

AbstractThe introduction of quantum communications, enabled by advancements in quantum computing, is expected to play a significant role in the field of communications. Inherent properties of quantum objects, such as superposition and entanglement, have the potential to provide novel solutions to overcome the challenges encountered by classical communication systems in bandwidth‐intensive applications such as media transmission. This research explores the performance of a quantum communication system in image transmission using quantum superposition and investigates its performance using a simple quantum channel model. With an increase in channel noise, there are significant gains in the rate distortion performance of images transmitted over the quantum channel compared to an ideal classical channel. This novel attempt at constructing a quantum communication‐based image transmission system indicates the potential of the approach to be applied to satisfy the ever‐increasing demands of high‐quality media transmission applications.

Antena Dwi Port Dwi Pengutuban Bulat terinspirasi Bahan Meta untuk Sistem Komunikasi Satelit Kecil

This paper presents a dual circular polarized C-band patch antenna for a small satellite communication system The antenna consists of two different annular patch structure with three split ring resonators. The antenna is designed considering space environment and the smallest form of satellite structure. The antenna is fabricated space qualified substrate material Rogers 5880 with overall dimension of 85.22× 48.59 × 1.575 mm3. The antenna achieves circular polarization at 5.1 GHz and 5.2 GHz frequency for port 2 and port 1, respectively. The split ring resonator structures contribute to enhance antenna gain and axial beamwidth. Realized gain of 7.29 dB and 7.33 dB are achieved at 5.1 GHz and 5.2 GHz operating frequency with 3dB axial beamwidth of 170 ̊ and 153 ̊ , respectively. Antenna size and performance show that the antenna can be a potential candidate for smooth operation of small satellite communication system.

Enhanced mutual information neural estimators for optical fiber communication.

The accurate estimation of mutual information (MI) plays a vital role in understanding channel capacity and optimizing the performance of optical communications. While MI computations for the additive white Gaussian noise (AWGN) channel are well-established, they fall short when dealing with the challenges posed by nonlinear optical fiber channels due to an unknown channel model. For the first time, to our knowledge, this Letter introduces a mutual information neural estimator (MINE) for MI estimation in optical fiber communications. We propose an enhanced MINE (E-MINE), achieved by enlarging the training batch size to improve estimation accuracy and stability. Our findings reveal that the E-MINE achieves highly accurate estimations in the AWGN channel and maintains strong consistency with symbol-by-symbol MI estimations, comparable to Monte Carlo (MC) methods based on a Gaussian distribution in long-haul optical fiber channels. Furthermore, with multi-symbol estimation, the E-MINE yields a 0.16 bits/4D-symbol improvement in our experiments. We anticipate that our findings will drive further research in the field, opening new possibilities for enhancing communication systems design and performance using deep learning techniques.

Evaluating energy harvesting UAV-NOMA network with random user pairing in the finite blocklength regime

This study proposes an integrated system that combines energy harvesting (EH) enabled unmanned aerial vehicles (UAVs) with non-orthogonal multiple access (NOMA) to enhance communication system performance within a cellular network. Addressing the limitations of existing analyses that often assume an infinite blocklength scenario, we explore EH-enabled UAV-NOMA systems within a cellular framework under a finite blocklength (FBL) scenario. The study investigates the complex interactions and advantages resulting from the integration of EH, NOMA, and UAV technologies, aiming to assess whether EH can sustain communication within this framework. The network model considers base stations (BSs), UAVs, and terrestrial devices distributed with independent Poisson point processes (PPPs) over a large area. In this network, BSs employ NOMA to serve cell center devices directly, while cell edge devices, which are nor in direct contact with BS, are served via simultaneous wireless information and power transfer (SWIPT) enabled UAVs. The study derives metrics including joint harvesting and decoding probability for a randomly selected UAV, coverage probability (CP) for cell devices, and end-to-end block error rate (BLER) probabilities for typical device pairs. The findings demonstrate that the proposed scheme effectively supplies all the necessary transmit power for communication purposes through EH, achieving reasonable reliability. Additionally, the study highlights the importance of considering a combination of blocklengths from different phases to achieve optimal performance, rather than solely relying on an increment in blocklength. Finally, the effects of parameter variations on network performance are examined.

Optimizing DSFH communication system performance via multi-feedback unsaturated tri-stable stochastic resonance for enhancement of periodic signal

To address the challenges in dual-sequence frequency-hopping (DSFH) communication caused by the difficulty in detecting intermediate-frequency (IF) signals under low signal-to-noise ratio conditions, this study proposes a method based on detecting enhanced periodic signals using a multi-feedback unsaturated tri-stable stochastic resonance (MFUTSR) system. Initially, we construct an unsaturated tri-stable stochastic resonance (UTSR) system by leveraging the anti-saturation characteristics of the segmented potential function. This UTSR system is then serially connected with a monostable system and incorporates feedback control to establish the MFUTSR system. Applying the adiabatic approximation theory, we derive the steady-state probability density (SPD) and signal-to-noise ratio (ISNR) of the MFUTSR system, investigating the influence of system parameters on these factors. Finally, to enhance the reliability of the DSFH communication system, we introduce a new evaluation metric, AC. Through numerical simulations and practical application in DSFH communication systems, it can be concluded that the MFUTSR system has significant advantages in periodic feature enhancement and noise suppression. Additionally, using AC as the evaluation metric for symbol decision can greatly reduce the system's bit error rate (BER). The innovative MFUTSR system introduced in this study enhances periodic signal detection in DSFH communication, demonstrating superior robustness against noise and significantly improving system reliability.

Non-orthogonal Multiple Access (NOMA) Channel Estimation for Mobile & PLC-VLC Based Broadband Communication System

Background: The paper focuses on enhancing the performance of 5G wireless mobile communication systems. Furthermore, it addresses the increasing demand for high data rates, improved channel capacity, and spectrum efficiency outlined by the 3rd Generation Partnership Project (3GPP) protocol. Objective: To develop an innovative Non-Orthogonal Multiple Access (NOMA)-based channel estimation (CE) model aimed at improving the performance of 5G wireless mobile communication systems Methods: A proportionate recursive least squares (PRLS) algorithm is utilized for estimating the characteristics of practical Rayleigh fading channels. The applicability of the PRLS algorithm is investigated in Lambertian channels for indoor broadband communication systems such as power line communication (PLC) and visual light communication (VLC) systems. Results: The assessment of evaluation metrics, including mean square error (MSE), bit error rate (BER), spectral efficiency (SE), energy efficiency (EE), capacity, and data rate, have been analysed. Faster convergence and higher accuracy compared to existing state-of-the-art approaches have been demonstrated. Conclusion: The NOMA-based channel estimation model presents significant promise in enhancing the performance of 5G wireless communication systems. The demands for higher data rates and improved spectral efficiency as per 3GPP standards have been addressed.

An Improved Remote Sensing Retrieval Method for Elevated Duct in the South China Sea

Elevated duct is an atmospheric structure characterized by abnormal refractive index gradients, which can significantly affect the performance of radar, communication, and other systems by capturing a portion of electromagnetic waves. The South China Sea (SCS) is a high-incidence area for elevated duct, so conducting detection and forecasts of the elevated duct in the SCS holds important scientific significance and practical value. This paper attempts to utilize remote sensing techniques for extracting elevated duct information. Based on GPS sounding data, a lapse rate formula (LRF) model and an empirical formula (EF) model for the estimation of the cloud top height of Stratocumulus were obtained, and then remote sensing retrieval methods of elevated duct were established based on the Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data. The results of these two models were compared with results from the elevated duct remote sensing retrieval model developed by the United States Naval Postgraduate School. It is shown that the probability of elevated duct events was 79.1% when the presence of Stratocumulus identified using GPS sounding data, and the trapping layer bottom height of elevated duct well with the cloud top height of Stratocumulus, with a correlation coefficient of 0.79, a mean absolute error of 289 m, and a root mean square error of 598 m. Among the different retrieval models applied to MODIS satellite data, the LRF model emerged as the optimal remote sensing retrieval method for elevated duct in the SCS, showing a correlation coefficient of 0.51, a mean absolute error of 447 m, and a root mean square error of 658 m between the trapping layer bottom height and the cloud top height. Consequently, the encouraging validation results demonstrate that the LRF model proposed in this paper offers a novel method for diagnosing and calculating elevated ducts information over large-scale marine areas from remote sensing data.

Propagation Modeling of Unmanned Aerial Vehicle (UAV) 5G Wireless Networks in Rural Mountainous Regions Using Ray Tracing

Deploying 5G networks in mountainous rural regions can be challenging due to its unique and challenging characteristics. Attaching a transmitter to a UAV to enable connectivity requires a selection of suitable propagation models in such conditions. This research paper comprehensively investigates the signal propagation and performance under multiple frequencies, from mid-band to mmWaves range (3.5, 6, 28, and 60 GHz). The study focuses on rural mountainous regions, which were empirically simulated based on the Skardu, Pakistan, region. A complex 3D ray tracing method carefully figures out the propagation paths using the geometry of a 3D environment and looks at the effects in line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. The analysis considers critical parameters such as path loss, received power, weather loss, foliage loss, and the impact of varying UAV heights. Based on the analysis and regression modeling techniques, quadratic polynomials were found to accurately model the signal behavior, enabling signal strength predictions as a function of distances between the user and an elevated drone. Results were analyzed and compared with suburban areas with no mountains but more compact buildings surrounding the Universiti Kebangsaan Malaysia (UKM) campus. The findings highlight the need to identify the optimal height for the UAV as a base station, characterize radio channels accurately, and predict coverage to optimize network design and deployment with UAVs as additional sources. The research offers valuable insights for optimizing signal transmission and network planning and resolving spectrum-management difficulties in mountainous areas to enhance wireless communication system performance. The study emphasizes the significance of visualizations, statistical analysis, and outlier detection for understanding signal behavior in diverse environments.

On the performance of a hybrid optical communication system: MGDM–FSO for challenging environments

On the performance of a hybrid optical communication system: MGDM–FSO for challenging environments

Enhanced Ultra-Wideband Communication System with OFDM Modulation: Performance Analysis in LOS and NLOS Conditions

Ultra-wideband (UWB) communication systems, employing Orthogonal Frequency Division Multiplexing (OFDM) modulation, are renowned for their high data rates, low power consumption, and robust performance in multipath environments. However, these systems face significant challenges in varying propagation conditions, specifically under Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) scenarios. In LOS conditions, the signal travels directly from the transmitter to the receiver without obstructions, typically resulting in optimal performance characterized by high transmission efficiency, strong Signal-to-Noise Ratio (SNR), low Bit Error Rate (BER), and maximum throughput. Conversely, NLOS conditions involve obstructions and reflections that cause multipath propagation and signal degradation. This leads to reduced transmission efficiency, lower SNR, higher BER, and diminished throughput. This study examines the performance of an UWB communication system using OFDM modulation in both LOS and NLOS conditions. The performance metrics evaluated include transmission efficiency, SNR,BER, and throughput. In LOS conditions, the system demonstrates high transmission efficiency, superior SNR, minimal BER, and maximum throughput due to the unobstructed signal path. In contrast, NLOS conditions result in decreased transmission efficiency, lower SNR, increased BER, and reduced throughput due to signal attenuation and multipath effects. These findings highlight the significant impact of environmental conditions on UWB-OFDM system performance and underscore the importance of optimizing such systems for reliable communication in varied deployment scenarios.

Enhanced resource optimization with the unevenness coefficients use in regular and irregular graph-based networks

The paper presents a simulation-based study of the impact of transmission resource reallocation on the performance of a communication network. The study considers the unevenness coefficients use to control network resources allocation. The results show that adjusting the transmission resource allocation based on the above- mentioned parameter can significantly improve network performance, leading to a equalization of network characteristics, and all of this without increasing the resources pool. The study’s findings provide valuable insights for network designers and operators seeking to optimize network performance in communication systems.

Research on signal equalization technology based on visible light communication

Abstract Visible Light Communication (VLC) transmits signals through visible light and realizes the two functions of lighting and communication at the same time without the need for other hardware equipment. There are still some shortcomings in the visible light communication system. The optical signal propagated indoors is affected by inter-symbol interference (ISI) and external light noise at the receiving end. The signal will be severely distorted. These factors will significantly reduce the accuracy of the received signal decision, thereby seriously affecting the performance of the visible light communication system. Given the problems of intersymbol interference and optical noise in indoor visible light systems, this article studies adaptive equalization technology and modulation and demodulation technology suitable for visible light communication systems and improves the signal-receiving end equalization. Based on the existing equalizer structure, we combined the advantages of two different equalizers and optimized their combined structure parameters. On this basis, we added the MAP algorithm and proposed a hyperbolic tangent function to improve the traditional error function. The defects speed up the convergence speed without changing the mean square error. Experimental results show that the algorithm has improved in convergence performance. The algorithm’s convergence speed is 53.6% higher than the traditional algorithm, the steady-state error is reduced by about 6 dB, and the steady-state error of the algorithm is reduced by about 5 dB respectively.

Kirchhoff meets Johnson: In pursuit of unconditionally secure communication

AbstractNoise: an enemy to be dealt with and a major factor limiting communication system performance. However, what if there is gold in that garbage? In conventional engineering, our focus is primarily on eliminating, suppressing, combating, or even ignoring noise and its detrimental impacts. Conversely, could we exploit it similarly to biology, which utilizes noise‐alike carrier signals to convey information? In this context, the utilization of noise, or noise‐alike signals in general, has been put forward as a means to realize unconditionally secure communication systems in the future. In this tutorial article, we begin by tracing the origins of thermal noise‐based communication and highlighting one of its significant applications for ensuring unconditionally secure networks: the Kirchhoff‐law‐Johnson‐noise (KLJN) secure key exchange scheme. We then delve into the inherent challenges tied to secure communication and discuss the imperative need for physics‐based key distribution schemes in pursuit of unconditional security. Concurrently, we provide a concise overview of quantum key distribution schemes and draw comparisons with their KLJN‐based counterparts. Finally, extending beyond wired communication loops, we explore the transmission of noise signals over‐the‐air and evaluate their potential for stealth and secure wireless communication systems.

Present Development of Software for Railway Safety

Railway is Cyber-Physical System (CPS), which is distributed over a large territory. It requires secure communication not only among various parts of system, but also with operation center. Building its own communication networks by the railway system operator is financially demanding, which is why more or less open communication systems are used. This is connected with higher requirements for the security of applications, operated in a CPS. European project COSMSOS has been creating a tool that applies DevOps development technologies from the IT field to the field of embedded systems, to which railway system belong. The article shows that this very complex software must be adapted to real requirements, which are put on railway operation system safety.

Design and Analysis of a Dual-Band Microstrip Patch Antenna for Sub-6 GHz Applications

This paper explores the design, simulation, and analysis of a dual-band Microstrip patch antenna designed to operate efficiently at frequency ranges of 3.32 GHz - 3.62 GHz and 4.72 GHz - 6.83 GHz, utilizing Ansys High-Frequency Structure Simulator (HFSS) software. The primary objective is to enhance performance metrics such as bandwidth, gain, and radiation efficiency to meet the requirements of applications necessitating concurrent operation at both frequency bands. The study involves a comprehensive design, iterative simulation, and detailed analysis using Ansys HFSS, with customized design considerations aimed at optimizing performance for modern wireless communication systems. The research was conducted in a simulated environment over a period that included iterative design processes, multiple simulation runs, and thorough analysis phases. Methodologically, the study focused on iterative design refinement to improve key performance parameters such as reflection coefficient, gain, radiation efficiency, Voltage Standing Wave Ratio (VSWR), and relative permittivity at the specified frequency bands. Results indicate that at 3.32 GHz - 3.62 GHz, the antenna achieves a reflection coefficient of -5 dB, a gain of 2.77 dB, a radiation efficiency of 0.7429, and a VSWR of 1.9299. At the higher frequency range of 4.72 GHz - 6.83 GHz, the antenna exhibits a reflection coefficient of -20.5213 dB, a gain of 3.34 dB, a radiation efficiency of 0.7, and a VSWR of 1.2203. These findings underscore the antenna's capability to deliver improved performance metrics across both frequency bands. In conclusion, the dual-band Microstrip patch antenna designed and analyzed through Ansys HFSS demonstrates significant potential for use in contemporary wireless communication systems, offering enhanced bandwidth, gain, and radiation efficiency suitable for multi-frequency applications.