Link Performance Analysis Research Articles

Performance Analysis of Free Space Optical Communication under Scintillation Effect

Free-Space Optical communication (FSO) offers unregulated bandwidth of up to 200 THz, security, higher speed, unlimited data rate and shortest installation time. However, weather attenuation, especially scintillation, has a massive impact on the performance of the FSO transmission channel. This paper evaluates link availability and effect of scintillation on FSO performance in terms of eye diagrams, Bit Error Rate (BER), Q-factor, and signal-to noise ratio. Our work used data collected from January 2018 to December 2021 by Tanzania Meteorological Authority (TMA) in Mwanza and Arusha regions for link availability and performance analysis. Simulation was performed to determine the FSO link availability, and we analyzed the scintillation effect on FSO performance using Submarine Laser Communication II and Hufnagel Valley (HV) day prediction models. It is observed that the HV day model performs better in predicting scintillation intensity compared to the former. In both regions, for the same transmission power of 20 dBm, the signal quality is better for a distance of 6 km where the BER value is found to be 10-8. These results suggest that, to achieve high-speed data transmissions, the maximum separating distance between FSO transceivers should not exceed 6 km.

The Analysis of FSO Link Performance in Ulaanbaatar

Recently, developed countries are leading in telecommunications technology, and many studies are being conducted to transmit information through the free space (FSO) or atmosphere using optical frequency light waves. The natural factors that most affect the propagation of optical light waves are fog, rain, and snow. Ulaanbaatar is the capital of Mongolia and has an extreme and variable climate. This paper is devoted to analyzing FSO link performance during data transmission in Ulaanbaatar during heavy rain months (July-August) and simulation using OptiSystem software. Marshall and Palmer's model was used for data transmission using FSO link performance to estimate the rainfall reduction, and several factors such as BER rate and Q factor were investigated. We have made a detailed assessment of the result of rainfall on the FSO system in Mongolia based on the technical data on the weather in Ulaanbaatar in 2018, 2019, and 2020 for the three meteorological station servers of the world weather online site www.worldweatheronline.com.

Channel Modeling for In-Body Optical Wireless Communications

Next generation in-to-out-of body biomedical applications have adopted optical wireless communications (OWCs). However, by delving into the published literature, a gap is recognized in modeling the in-to-out-of channel, since most published contributions neglect the particularities of different types of tissues. In this paper, we present a novel pathloss and scattering models for in-to-out-of OWC links. Specifically, we derive extract analytical expressions that accurately describe the absorption of the five main tissues’ constituents, namely fat, water, melanin, and oxygenated and de-oxygenated blood. Moreover, we formulate a model for the calculation of the absorption coefficient of any generic biological tissue. Next, by incorporating the impact of scattering in the aforementioned model, we formulate the complete pathloss model. The developed model is verified by means of comparisons between the estimated pathloss and experimental measurements from independent research works. Finally, we illustrate the accuracy of the proposed model in estimating the optical properties of any generic tissue based on its constitution. The extracted channel model is expected to enable link budget analysis, performance analysis, and theoretical framework development, which will boost the design of optimized communication protocols for a plethora of biomedical applications.

Link performance evaluation of terrestrial FSO model for predictive deployment in Bhubaneswar smart city under various weather conditions of tropical climate

This paper proposes the link performance analysis of the terrestrial free-space optic (FSO) model, intended for deployment in Bhubaneswar smart city. The challenges of atmospheric adversity and its impact on the performance of FSO model have been analyzed from the real-time measured visibility data. A comparative study of different statistical models addressing the relation between measured visibility data and atmospheric attenuation has been carried out. The atmospheric losses such as haze, scintillation, rain, fog are considered for the link analysis due to the tropical savanna climate of the Bhubaneswar city. Thereafter the link margin is calculated for summer, rainy, winter season for the feasible establishment of FSO link. Comparison between two low absorption optical wavelengths such as 850 nm and 1550 nm has been considered for performance analysis. This is because of the commercial availability of optical components. Performance metrics such as received signal power, bit error rate (BER), signal to noise ratio (SNR), link margin has been used for the link performance analysis for a best fit FSO model for deployment in the city. Finally, the maximum achievable data rate is calculated for FSO link in all the three seasons for ensuring high-quality network reach.

Analysis of Free Space Optics Link Performance Considering the Effect of Different Weather Conditions and Modulation Formats for Terrestrial Communication

AbstractFree space optics (FSO) links provide an effectual and efficient way of transmission of data throughout free channels due to its higher bandwidth and inbuilt capability of security. In this research analysis, the FSO link is evaluated on the basis of Q value for different modulation formats and weather conditions. Gamma–Gamma and log-normal scintillation models have been analyzed for different index of refraction in terms of Q factor versus a range of a proposed FSO link. Attenuation increases during the occurrence of different fog conditions, and there might be complete link failure in the case of dense fog and for some of the cloud conditions.

A Laser-Forwarded Coherent Transceiver in 45-nm SOI CMOS Using Monolithic Microring Resonators

For the silicon photonic links to meet the target bit error rate (BER), the laser source must output enough optical power to overcome the optical channel loss and limited receiver sensitivity. Combined with poor wall-plug efficiency, this optical power requirement makes the electrical power consumed by the laser source a significant portion of the link energy cost. This article proposes a laser-forwarded coherent link that greatly reduces the required laser optical power by averaging optical path loss between the main and forwarded paths and by improving the receiver sensitivity using a homodyne coherent detector. The link performance analysis reveals that the laser forwarded link improves the laser power budget by ≈6-8 dB compared with a conventional intensity-modulation/direct detection link using typical photonic link components. To demonstrate the laser forwarded link, a microring resonator phase modulator, a balanced detector, and a 3-dB coupler are integrated with CMOS circuits in a GFUS 45-nm SOI process. The transmit driver and the receiver consume 40 and 450 fJ/bit, respectively. Aided by ≈8-dB boost from laser forwarding and the coherent detection gain, the receiver achieves -15.6-dBm optical modulation amplitude sensitivity. The link operates at 10 Gb/s with BER <; 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> and electrical energy efficiency of 2.3 pJ/bit.

An Adaboost Based Link Planning Scheme in Space-Air-Ground Integrated Networks

The Space-air-ground integrated network (SAGIN) has been a valuable architecture for communication support due to its characteristics of wide coverage and low transmission delay. Both low earth orbit (LEO) satellites and UAVs can serve as relay nodes to provide reliable communication services for ground devices. However, the design of data transmission links (DTL) in SAGIN is not easy, considering different accessing layers and resource usage of network segments. Moreover, network topology, available resources, and relative motion need to be analyzed comprehensively for the deployment of DTLs. To address these problems in a heterogeneous SAGIN network, the software defined networking (SDN) architecture is utilized to realize global knowledge acquisition. Then a traffic prediction method based on autoregressive moving average (ARMA) model is utilized to forecast the resource usage of SAGIN segments. After the analysis of link performance, the Adaboost algorithm is used to classify network nodes according to their data transmission capacity for DTL deployment. Simulation results show that the proposed Adaboost-based link planning scheme is feasible and effective.

A Compact Low-Power LoRa IoT Sensor Node with Extended Dynamic Range for Channel Measurements.

As sub-GHz wireless Internet of Things (IoT) sensor networks set the stage for long-range, low-data-rate communication, wireless technologies such as LoRa and SigFox receive a lot of attention. They aim to offer a reliable means of communication for an extensive amount of monitoring and management applications. Recently, several studies have been conducted on their performance, but none of these feature a high dynamic range in terms of channel measurement. In this contribution an autonomous, low-power, LoRa-compatible wireless sensor node is presented. The main uses for this node are situated in LoRa channel characterization and link performance analysis. By applying stepped attenuators controlled by a dynamic attenuation adjustment algorithm, this node provides a dynamic range that is significantly larger than what is provided by commercially available LoRa modules. The node was calibrated in order to obtain accurate measurements of the received signal power in dBm. In this paper, both the hardware design as well as some verification measurements are discussed, unveiling various LoRa-related research applications and opportunities.

실시간 해상 정보 수집을 위한 LoRa 링크 성능분석

실시간 해상 정보 수집을 위한 LoRa 링크 성능분석

Analysis and Simulation of Link Performance for Underwater Wireless Optical Communications

This paper investigates how to increase communication distance of underwater wireless optical communication system. In order to analyze the communication distance of UWOC, the performance of optical transmitter and receiver, underwater channel characterization and modulation schemes were discussed.

Modeling and Link Performance Analysis of Busbar Distribution Systems for Narrowband PLC

Modeling and Link Performance Analysis of Busbar Distribution Systems for Narrowband PLC

Link Optimization and Performance Analysis of a 40 Gbps DQPSK Modulated Ultra DWDM System with 32 Orthogonally Polarized channels

Abstract The demand for higher speed at a lesser transmission cost per bit resulted in growth of optical networks with improved spectral efficiency even at narrower channel spacing. Incorporation of multilevel modulation formats in DWDM system led to the exploration of the 25 GHz channel grid, popularly known as Ultra Dense Wavelength Division Multiplexed (UDWDM) systems, opening new research frontiers. At such channel spacing's, non-linear optical effects impose severe system impairments and hence robust modulation schemes are currently being investigated. This paper presents a simulative model to implement and analyze alternative polarized DQPSK modulated UDWDM system to evaluate its resilience to XPM and fiber nonlinearity. An UDWDM system supporting 32 channels, each operating at 40 Gbps and spaced at 25 GHz is studied numerically for long-haul optical communication system using OptiSystem simulator to estimate OSNR penalties to mitigate XPM effects. The major detrimental factors encountered in link design have been estimated to evaluate the system performance in terms of Q value for different number of channels and with varied input power. The analysis reports acceptable performance for DQPSK format up to a link distance of 1500 Km and also claims a better tolerance to dispersion and nonlinearities at higher input power levels.

4.4GHz 대역을 활용한 항공기내 무선통신 링크 성능 분석

4.4GHz 대역을 활용한 항공기내 무선통신 링크 성능 분석

Analysis of link performance and robustness of homodyne BPSK for airborne backbone laser communication system

The high altitude turbulence is described by the “Clear 1” model in terms of refractive-index structure. The outage and Bit Error Rate (BER) performance of airborne communication links under atmospheric turbulence and aero-optics effects of homodyne binary phase shift keying (BPSK) system is deduced in the high altitude turbulence channel, the relation of probability of fade, mean fade time with flight altitude and transmission distance is analyzed, the Bit Error Rate (BER) vary characteristic along with the mean signal noise rate signal noise rate (SNR) of different modulates is discussed in the gamma–gamma turbulence channel. The results show that atmospheric turbulence and aero-optic effects can greatly reduce the SNR that would occur in the absence of optical turbulence, leading in some cases to unacceptable fade levels or BERs. The average SNR is 26dB for BPSK to achieve a BER of 10−6. A bit error rate of 5.94×10−10 at 200km propagation distance was achieved employing a homodyne BPSK based modem.

Propagation Measurement on Earth-Sky Signal Effects for High Speed Train Satellite Channel in Tropical Region at Ku-Band

Recent advances in satellite communication technologies in the tropical regions have led to significant increase in the demand for services and applications that require high channel quality for mobile satellite terminals. Determination and quantification of these requirements are important to optimize service quality, particularly in the Malaysian region. Moreover, the tests on current satellite propagation models were carried out at temperate regions whose environmental characteristics are much different from those in Malaysia. This difference renders these propagation models inapplicable and irrelevant to tropical regions in general. This paper presents the link characteristics observations and performance analysis with propagation measurements done in tropical region to provide an accurate database regarding rain and power arches supply (PAs) attenuations in the tropics for mobile scenarios. Hence, an extension for improving the performance assessment and analysis of satellite/transmission has been achieved. The Malaysia propagation measurement for mobile scenario (Malaysia-PMMS) enables first-hand coarse estimation and attenuation analysis, because the attenuation resulting from rain and PAs becomes easily amenable for measurement. Parallel to that, the measured attenuation has been compared with that of the simulated output at noise floor level. The underlying analytical tool is validated by measurements specific at tropical region, for dynamic model of mobile satellite links operating at higher than 10 GHz.

Simplified model and experimental validation for ultraviolet single-scattering channels

For nonline-of-sight ultraviolet communication links, a simple and concise parametric expression (PE) of channel path loss is valuable for link performance analysis in typical scenarios. It is observed that the light energy in the scattering volume can be approximated using a line integral. Combining curve fitting for the scattering phase function and the mean value theorem of integrals, we propose a simple but highly accurate PE. It matches well with the Monte Carlo simulations for typical LED-based communication with small beam divergence (<45°); when the beam divergence is smaller than 10°, their differences are less than 1 dB in most geometrical conditions. The proposed PE also shows good consistency with our outdoor experimental measurements, and the reported experimental results in the literature.

Network security situational assessment based on link performance analysis

Concerning the fusion essence of network situational assessment and the defect of being unaware of the unknown attack in the existing Analytic Hierarchy Process( AHP), a network security evaluation method based on link security situation was proposed. With the help of the theory of network performance analysis, the network security situational assessment model based on link performance analysis was proposed. Firstly, the paper calculated every link's security situational value and showed them in a matrix; secondly, used every link's weight and security situational value to get the network security situational value which was shown in vector. The experimental results show that the proposed method can not only reflect the changes of both the partial and entire security situation but also apperceive unknown attack, which provides administrator with much convenience.

双频段信号同步调制下星间微波光子链路性能分析

双频段信号同步调制下星间微波光子链路性能分析

EARTH-SKY LINK QUALITY PERFORMANCE FOR FIXED AND MOBILE SCENARIOS IN TROPICAL REGIONS

Recent advances in satellite communication technologies in the tropical regions have led to signiflcant increase in the demand for services and applications that require high channel quality for flxed and mobile satellite terminals. Due to lack of reliable investigations regarding accurate performance evaluation, experiments, and analysis on the satellite communication link in tropical regions under atmospheric impairments for both scenarios, accurate signal quality performance analysis is necessary. This paper presents the link characteristics observations and performance analysis with propagation measurements done in tropical region to provide an accurate database regarding rain attenuation in the tropics for flxed and mobile scenarios. The paper also presents a newly developed extension attached to the measurements setup for improved packet error rate (PER) performance evaluation related to the degradations occur in channel quality for difierent types of impairments (rain, mobility, and physical obstacles) for 4 modulation schemes, namely QPSK, 8-PSK, 16-QAM and 32-QAM. The results show that the rain impairments at Ku band cause up to 12.5dB and 23dB at 77.5 - and 40.1 - elevation angles respectively in two tropical regions inside Malaysia for flxed scenario with a signiflcant increase in PER at higher M-ary modulation schemes. For mobile scenario the PER appeared at higher M-ary scheme due to the lower signal power degradation in which, in turn, exceeded 1dB when the vehicle speed exceed 100km/hr

Research on Design Method for Heavy-Duty Asphalt Pavements and Its Application

Abstract Premature damage is currently the main problem with heavy-duty asphalt pavements. In order to decrease such premature damage, it is necessary to develop a new design system meeting the requirements of heavy-duty pavements. Based on considerable field investigations and mechanistic analysis, a five-phase design procedure, including data collection, structural combination design, structural thickness design, material testing and examination, and a final decision, was established. The procedure is a comprehensive design tool employing performance-related structural design consideration and mechanistic-based material design consideration that can link performance analysis, structural design, and material design (tests). After consideration of the extensive pavement performance data collected and subsequent analysis, relevant design equations and design criteria were proposed, including whole life asphalt pavement structural behavior equations, life cycle cost analysis models, field fatigue equations, and a shear-based rutting prediction model. As research progressed, test roads and pilot roads were constructed in ten provinces of China, and the first test road has been used successfully for 15 years.