Showing papers on "Cumulative distribution function published in 2022"
TL;DR: Considering the imperfect CSI from the RIS to the destination, the cumulative distribution function (CDF) of the end- to-end signal-to-interference-plus-noise ratio (SINR) is developed and the closed-form expressions of the outage probability, average bit error rate, and average capacity are derived.
Abstract: The impact of imperfect channel state information (CSI) on a reconfigurable intelligent surface (RIS)-aided wireless system is investigated in this letter. More specifically, considering the imperfect CSI from the RIS to the destination, we develop the cumulative distribution function (CDF) of the end-to-end signal-to-interference-plus-noise ratio (SINR). Then, using the CDF, we derive the closed-form expressions of the outage probability (OP), average bit error rate (BER), and average capacity. Furthermore, we also derive the asymptotic OP, average BER, and average capacity at high signal-to-noise ratio (SNR). Simulation results show that inaccurate CSI results in zero diversity order and a floor phenomenon. Also, numerical results demonstrate that the derived closed-form expressions match the simulated results.
21 citations
TL;DR: In this article , a machine learning model for probabilistic rainfall nowcasting at 10 min intervals for short lead times - from 30 min up to 6 h - was proposed. But the model is not suitable for operational early warning system.
Abstract: Rainfall nowcasting supports emergency decision-making in hydrological, agricultural, and economical sectors. However, short-term prediction is challenging because meteorological variables are strongly interconnected and rapidly change during an event. Since machine learning do not require any previous physical assumption, this study investigates their ability to provide reliable and quick forecasts. This paper proposes a machine learning model for probabilistic rainfall nowcasting at 10 min intervals for short lead times - from 30 min up to 6 h. The model employs cumulative rainfall fields from station data as inputs for a feed forward neural network to predict rainfall interval and the corresponding probability of occurrence. Cumulative rainfall depths from station data were used to overcome the lack of temporal memory of the feed forward neural networks. In this way, using only the current rain field as input, the model exploited pattern recognition techniques combining both temporal - cumulative rainfall depth - and spatial - cumulative rainfall field – information. Based on 359 rain events observed in an area of 1619 km2 in Southern Italy, 95 machine learning models were independently trained for 19 recording stations and for each target lead-time (30, 60, 120, 180 and 360 min). Comprehensive nowcasts verification was performed to analyse the reliability of probabilistic nowcasts using both continuous (RMSE and RAE) and categorical (POD, FAR and CSI) indicators. The performance of the models was also compared with the results of Eulerian Persistence. All the models produced consistent nowcasts and learnt the complex relationship describing space–time rainfall evolution. As expected, predictive accuracy gradually decreased as the lead-time increase, according to physically based models. Results showed that the use of both temporal and spatial information enables the model to predict short-term rainfall using only the current measurements as input, resulting in a rapid, easily replicable and convenient nowcasting approach. The procedure is an effective way to predict multi-step rainfall fields and is suitable for operational early warning system.
16 citations
TL;DR: In this article , the authors proposed a two-hop integrated radio frequency-visible light communication (RF-VLC) system which may provide a better option to transceive between the hospitals and some laboratory to transfer patient's information.
16 citations
TL;DR: In this paper, the authors proposed a two-hop integrated radio frequency-visible light communication (RF-VLC) system which may provide a better option to transceive between the hospitals and some laboratory to transfer patient's information.
16 citations
TL;DR: Terahertz communications in the presence of pointing error impairments (misalignment) and under random fog conditions is considered and closed-form expressions for the outage probability, average symbol error rate (SER), and ergodic channel capacity are derived.
Abstract: In this letter, we consider Terahertz (THz) communications in the presence of pointing error impairments (misalignment) and under random fog conditions. We derive closed-form expressions, in terms of I-function, for the probability density function (PDF) and the cumulative distribution function (CDF). Then, the PDF and the CDF are employed to derive closed-form expressions for the outage probability, average symbol error rate (SER), and ergodic channel capacity. Additionally, very tight simple approximations in the high signal-to-noise ratio for the outage probability and average SER are provided. The derived expressions are validated through numerical and Monte-Carlo simulation results.
11 citations
TL;DR: In this article , a nonlocal generalization of the standard probability theory based on the use of the general fractional calculus in the Luchko form is proposed, including nonlocal (general fractional) generalizations of probability density, cumulative distribution functions, probability, average values, and characteristic functions.
Abstract: Nonlocal generalization of the standard (classical) probability theory of a continuous distribution on a positive semi-axis is proposed. An approach to the formulation of a nonlocal generalization of the standard probability theory based on the use of the general fractional calculus in the Luchko form is proposed. Some basic concepts of the nonlocal probability theory are proposed, including nonlocal (general fractional) generalizations of probability density, cumulative distribution functions, probability, average values, and characteristic functions. Nonlocality is described by the pairs of Sonin kernels that belong to the Luchko set. Properties of the general fractional probability density function and the general fractional cumulative distribution function are described. The truncated GF probability density function, truncated GF cumulative distribution function, and truncated GF average values are defined. Examples of the general fractional (GF) probability distributions, the corresponding probability density functions, and cumulative distribution functions are described. Nonlocal (general fractional) distributions are described, including generalizations of uniform, degenerate, and exponential type distributions; distributions with the Mittag-Leffler, power law, Prabhakar, Kilbas–Saigo functions; and distributions that are described as convolutions of the operator kernels and standard probability density.
11 citations
TL;DR: In this article , the performance of a dual-hop relaying terahertz (THz) wireless communication system is investigated, where the behaviors of the two THz hops are determined by three factors, such as the deterministic path loss, fading effects, and pointing errors.
Abstract: In this article, the performance of a dual-hop relaying terahertz (THz) wireless communication system is investigated. In particular, the behaviors of the two THz hops are determined by three factors, such as the deterministic path loss, fading effects, and pointing errors. Assuming that both THz links are subject to the $\alpha $ - $\mu $ fading with pointing errors, we derive exact expressions for the cumulative distribution function (CDF) and probability density function (PDF) of the end-to-end signal-to-noise ratio (SNR). With these statistical expressions, some important performance metrics are evaluated, such as the outage probability (OP), average bit error rate (BER), and average channel capacity (ACC). Moreover, the asymptotic analyses are presented to obtain more insights. The results show that the dual-hop relaying scheme has better performance than the single THz link. Furthermore, the system diversity order depends on the fading parameters and pointing errors of both THz links. In addition, we extend the analysis to a multirelay cooperative diversity system and derive the asymptotic symbol error rate (SER) expressions. Finally, the derived analytical expressions are verified by the Monte Carlo simulation.
11 citations
TL;DR: In this paper , a mixed dual-hop free-space optical (FSO)-radio frequency (RF) communication system that serves the end user via a decode-and-forward (DF) relay employing hybrid automatic repeat request (H-ARQ) protocols on both hops is proposed.
Abstract: Intelligent reflecting surface (IRS) is an emerging key technology for the fifth-generation (5G) and beyond wireless communication systems to provide more robust and reliable communication links. In this letter, we propose a mixed dual-hop free-space optical (FSO)-radio frequency (RF) communication system that serves the end user via a decode-and-forward (DF) relay employing hybrid automatic repeat request (H-ARQ) protocols on both hops. Novel closed-form expressions of the probability density function (PDF) and cumulative density function (CDF) of the equivalent end-to-end signal-to-noise ratio (SNR) are computed for the considered system. Utilizing the obtained statistics, we derive the outage probability (OP) and packet error rate (PER) of the proposed system by considering generalized detection techniques on the source-to-relay (S-R) link with H-ARQ protocol and IRS having phase error. We obtain useful insights into the system performance through the asymptotic analysis which aids to compute the diversity gain. The derived analytical results are validated using Monte Carlo simulation.
11 citations
TL;DR: A performance analysis is presented for an asymmetric two-hop amplify-and-forward (AF) relaying system with multiple relays in an underlay cognitive radio network (CRN), where a partial relay selection (PRS) is used to select the best relay for the signal transmission.
10 citations
TL;DR: In this article , the performance of a UAV-assisted, asymmetric, dual-hop radio frequency (RF)/FSO system with the amplified-and-forward relay protocol for the SAGIN is investigated.
Abstract: Space-air-ground integrated networks (SAGIN) within UAV-assisted free-space optical (FSO) communication systems can efficiently accommodate massive connections and provide highly reliable and seamless communications. In this work, we investigate the performance of a UAV-assisted, asymmetric, dual-hop radio frequency (RF)/FSO system with the amplified-and-forward relay protocol for the SAGIN. Specifically, the shadowed Rician fading is utilized in this study to characterize the shadowing effect on the RF signal for the satellite-to-UAV link. Meanwhile, the atmospheric turbulence effect on the optical signal for the UAV-to-terrestrial user link is modeled by the Málaga distribution fading, in view of the pointing error impairments. For comparison, the heterodyne detection technique is employed, as well as the intensity modulation with direct detection technique, in improving performance of the relay system. Thus, we derive the closed-form expressions for the cumulative distribution function, probability density function, the moment generating function, and particularly, the moments of the end-to-end RF/FSO system, in terms of Meijer’s G-function. Utilizing these derived formulae, the precise closed-form expressions for the outage probability, the average bit error rate (BER) with various modulation schemes, and the ergodic capacity are given. In specific, the tight asymptotic results for the outage probability and the average BER at the high SNR regions are derived using the asymptotic expansion of Meijer’s G-function. Furthermore, closed-form expressions are presented for the case that the FSO link experiences Gamma-Gamma distribution by changing some specific parameters. Finally, extensive numerical results validate the theoretical results with the Monte-Carlo simulation.
10 citations
TL;DR: In this paper , the performance of RIS-empowered free-space optical (RISE-FSO) systems was analyzed by unifying Fisher-Snedecor and Gamma-Gamma.
Abstract: Reconfigurable intelligent surface (RIS) is an excellent use case for line-of-sight (LOS) based technologies such as free-space optical (FSO) communications. In this paper, we analyze the performance of RIS-empowered FSO (RISE-FSO) systems by unifying Fisher-Snedecor ( ${\mathcal{F}}$ ), Gamma-Gamma ( $\cal {GG}$ ), and Malága ( $\cal {M}$ ) distributions for atmospheric turbulence with zero-boresight pointing errors over deterministic as well as random path-loss in foggy conditions with heterodyne detection (HD) and intensity modulation/direct detection (IM/DD) methods. By deriving the probability density function (PDF) and cumulative distribution function (CDF) of the direct-link (DL) with the statistical effect of atmospheric turbulence, pointing errors and random fog, we develop exact expressions of PDF and CDF of the resultant channel for the RISE-FSO system. Using the derived statistical results, we present exact expressions of outage probability, average bit-error-rate (BER), ergodic capacity, and moments of signal-to-noise ratio (SNR) for both DL-FSO and RISE-FSO systems. We also develop an asymptotic analysis of the outage probability and average BER and derive the diversity order of the considered systems. We validate the analytical expressions using Monte-Carlo simulations and demonstrate the performance scaling of the FSO system with the number of RIS elements for various turbulence channels, detection techniques, and weather conditions.
TL;DR: In this article , the performance of a reconfigurable intelligent surface (RIS)-assisted unmanned aerial vehicle (UAV) wireless system that is affected by mixture-gamma small-scale fading, stochastic disorientation and misalignment, as well as transceivers hardware imperfections.
Abstract: In this paper, we analyze the performance of a reconfigurable intelligent surface (RIS)-assisted unmanned aerial vehicle (UAV) wireless system that is affected by mixture-gamma small-scale fading, stochastic disorientation and misalignment, as well as transceivers hardware imperfections. First, we statistically characterize the end-to-end channel for both cases, i.e., in the absence as well as in the presence of disorientation and misalignment, by extracting closed-form formulas for the probability density function (PDF) and the cumulative distribution function (CDF). Building on the aforementioned expressions, we extract novel closed-form expressions for the outage probability (OP) in the absence and the presence of disorientation and misalignment as well as hardware imperfections. In addition, high signal-to-noise ratio OP approximations are derived, leading to the extraction of the diversity order. Finally, an OP floor due to disorientation and misalignment is presented.
TL;DR: In this article , a data-driven sparse polynomial chaos expansion-based surrogate model for the stochastic economic dispatch problem considering uncertainty from wind power is proposed, which can provide accurate estimations for the statistical information (e.g., mean, variance, probability density function, and cumulative distribution function) without requiring the probability distributions of random inputs.
Abstract: This letter proposes a data-driven sparse polynomial chaos expansion-based surrogate model for the stochastic economic dispatch problem considering uncertainty from wind power. The proposed method can provide accurate estimations for the statistical information (e.g., mean, variance, probability density function, and cumulative distribution function) for the stochastic economic dispatch solution efficiently without requiring the probability distributions of random inputs. Simulation studies on an integrated electricity and gas system (IEEE 118-bus system integrated with a 20-node gas system) are presented, demonstrating the efficiency and accuracy of the proposed method compared to the Monte Carlo simulations.
TL;DR: In this paper , the authors considered a new generalization of cumulative residual extropy (CRJ) introduced by Jahanshahi et al. called Weighted Cumulative Residual Extropy (WCRJ), and proposed an empirical version of the WCRJ to estimate this measure of uncertainty.
Abstract: This paper considers a new generalization of cumulative residual extropy (CRJ) introduced by Jahanshahi et al. [On cumulative residual extropy. Probab Eng Inf Sci. 2019. DOI:10.1017/S0269964819000196], called weighted cumulative residual extropy (WCRJ). This paper studies some properties of WCRJ of continuous lifetime distributions. Several results including various bounds, inequalities, and effects of linear transformations are obtained. Conditional WCRJ and some of its properties are discussed. Related studies of survival analysis are covered. Also, we propose an empirical version of the WCRJ to estimate this measure of uncertainty. Based on the asymptotic distribution of empirical WCRJ, a new test statistic is given for testing the equality of two cumulative distribution functions. The power of the proposed test statistic is compared to other traditional and new competing approaches. Some simulations are carried out to show how this newly proposed method is more powerful than the others for moderate to large sample sizes.
TL;DR: In this paper , a performance analysis is presented for an asymmetric two-hop amplify-and-forward (AF) relaying system with multiple relays in an underlay cognitive radio network (CRN), where a partial relay selection (PRS) is used to select the best relay for the signal transmission.
TL;DR: In this paper, the cumulative residual Tsallis entropy (CRTE) was introduced as an alternative dispersion measure for image quality assessment and its properties were investigated. But the authors considered the problem of estimating the CRTE by means of the empirical CRTE and used two empirical estimators of cumulative distribution function to estimate CRTE.
TL;DR: In this article , the authors used empirical cumulative functions of the distribution of the dynamics of a characteristic sign of an increment in the state of the gaseous medium in the premises when a thermal source of fire appears.
Abstract: The object of this study is the dynamics of a characteristic sign of an increment in the state of the gaseous medium in the premises when a thermal source of fire appears. The subject of the study is the type of an empirical cumulative function of the distribution of dynamics of a characteristic sign of an increment in the state of the gaseous medium in the absence and appearance of a thermal source of fire in the premises. As a characteristic feature, the probability of non-recurrence of the increments of the vector of states of the gaseous medium was chosen. The results of the study make it possible to quickly identify thermal sources of fire under uncertain conditions. The methodology for studying the empirical cumulative function of the distribution of the dynamics of the probability of non-recurrence of the increments of the vector of the state of the gas medium has been substantiated. The technique includes the implementation of seven consecutive procedures and makes it possible to explore the specified function for arbitrary time intervals. The empirical cumulative distribution function for two fixed time intervals of equal duration before and after the appearance of test thermal sources of fire in the laboratory chamber was investigated. It was established that the features of the empirical cumulative functions of the distribution of the dynamics of the probability of non-recurrence of the increments of the vector of the state of the gas environment allow for early detection of fire. The main sign of detection is a decrease in the fixed values of the empirical cumulative distribution function. For test thermal sources, fixed values of the empirical cumulative distribution function are in the range of 0.15–0.44. These probabilities are determined by the different ignition rate of the test thermal sources. The research results indicate the possibility of using the identified features of empirical cumulative distribution functions of the dynamics of the probability of non-recurrence of increments of the vector of the state of the gas environment for the early detection of fires
TL;DR: In this article , a generalized approach to the performance analysis of relay-aided communication systems for 5G-and-beyond scenarios is presented, where the relationship between the outage performance and cumulative distribution function (CDF) of the SNR is exploited to derive a universal expression of the outage probability that is valid for all fading scenarios, irrespective of their nature or complexity.
Abstract: This paper presents a generalized approach to the performance analysis of relay-aided communication systems for 5G-and-beyond scenarios. A dual-hop decoding and forwarding scheme is considered in the analysis. The relationship between the outage performance and cumulative distribution function (CDF) of the signal-to-noise ratio (SNR) is exploited to derive a universal expression of the outage probability that is valid for all fading scenarios, irrespective of their nature or complexity. Furthermore, an effort is made to parameterize the channel PDF in such a manner that reflects a practical fading scenario that is commonly encountered in current and future wireless communication systems. The analytical results obtained for various cases are validated through Monte-Carlo simulations.
TL;DR: In this paper , the authors proposed a novel method for assessing the small-failure probability by integrating the point-evolution kernel density (PKDE), SS, and polynomial chaos kriging (PCK), which reduced the implementation of the original performance function by PCK and enriched the training set using an adaptive strategy.
TL;DR: In this article , a UAV-assisted radio-frequency (RF)/free space optical (FSO) communication system under the amplified-and-forward protocol with variable gain is investigated.
Abstract: The Internet of Vehicles (IoV), as a development and complement of the Internet of Thing, has attracted extensive attention and is expected to play a crucial role in human society with the matured space-air-ground integrated networks (SAGIN). Here, we devote ourselves to establish and investigate a unmanned aerial vehicle (UAV)-assisted radio-frequency (RF)/free space optical (FSO) communication system under the amplified-and-forward protocol with variable gain. More specifically, we assume the RF link follows $\kappa -\mu $ fading and the FSO link experiences Málaga fading, which can characterize the atmospheric turbulence under weak-to-strong condition excellently. In addition, both the pointing errors impairment and the detection techniques for the FSO link are also taken into account. Novel analytical expressions for the end-to-end system, e.g., the cumulative distribution function, probability density function, and moment generating function, are proposed. By capitalizing on these results, some system metrics of the UAV-assisted relaying system are given with the Meijer’s G function. To providing more insights for this UAV-assisted system for SAGIN, high signal-to-noise approximations of these metrics are also presented. Furthermore, the approximated expressions for the outage probability and average BER are given in presence of nonpointing error effect. Finally, all these analytical results are validated with the Monte Carlo simulations.
TL;DR: In this article , the authors proposed a practical channel model for RIS-aided MIMO communications which considers the effects of RIS configurations, operating environments, path loss, scattering, etc.
Abstract: Reconfigurable intelligent surfaces (RIS) hold the potential to revolutionize the wireless communications industry via the dynamic control of the wireless channels to help achieve high data rates, high spectral and energy efficiencies, and low error rates, towards meeting the advanced specifications of B5G. In this context, this paper proposes a practical channel model for RIS-aided MIMO communications which considers the effects of RIS configurations, operating environments, path loss, scattering, etc. With this comprehensive channel model, the probability density function and the cumulative distribution function of the received signal-to-noise power ratio are derived by utilizing a double generalized K distribution, and closed-form expressions for the system’s error rate, outage probability, and channel capacity, are obtained. The analysis highlights the outperforming of the RIS-aided communications in indoor environments as compared to outdoor use cases due to the presence of less scatterers in the former.
01 Jun 2022
TL;DR: In this article , the authors developed an analytical framework for the statistical analysis of the battery recharging time (BRT) in reconfigurable intelligent surfaces (RISs)-aided wireless power transfer (WPT) systems.
Abstract: In this paper, we develop an analytical framework for the statistical analysis of the battery recharging time (BRT) in reconfigurable intelligent surfaces (RISs)-aided wireless power transfer (WPT) systems. Specifically, we derive novel closed-form expressions for the probability density function (PDF), cumulative distribution function, and moments of the BRT of the radio frequency energy harvesting wireless nodes. Moreover, a closed-form expression of the PDF of the BRT is obtained for the special case when the RIS consists of a large number of elements. Capitalizing on the derived expressions, we offer a comprehensive treatment for the statistical characterization of the BRT and study the impact of the system and battery parameters on its performance. Our results reveal that the proposed statistical models are analytically tractable, accurate, and efficient in assessing the sustainability of RIS-assisted WPT networks and in providing key design insights for large-scale future wireless applications. For example, we demonstrate that a 4-fold reduction in the mean time of the BRT can be achieved by doubling the number of RIS elements. Monte Carlo simulation results corroborate the accuracy of the proposed theoretical framework.
TL;DR: In this paper, a new one-parameter count distribution is proposed by combining Poisson and XLindley distributions, which can be used to model positively skewed data with leptokurtic shape.
Abstract: In this study, a new one-parameter count distribution is proposed by combining Poisson and XLindley distributions. Some of its statistical and reliability properties including order statistics, hazard rate function, reversed hazard rate function, mode, factorial moments, probability generating function, moment generating function, index of dispersion, Shannon entropy, Mills ratio, mean residual life function, and associated measures are investigated. All these properties can be expressed in explicit forms. It is found that the new probability mass function can be utilized to model positively skewed data with leptokurtic shape. Moreover, the new discrete distribution is considered a proper tool to model equi- and over-dispersed phenomena with increasing hazard rate function. The distribution parameter is estimated by different six estimation approaches, and the behavior of these methods is explored using the Monte Carlo simulation. Finally, two applications to real life are presented herein to illustrate the flexibility of the new model.
TL;DR: The secrecy performance of a mixed free space optical (FSO)/radio frequency (RF) integrated satellite-high altitude platform (HAP) relaying networks for terrestrial multiusers with the existence of an eavesdropper is investigated and results depict that heterodyne detection outperforms the intensity modulation direct detection.
Abstract: In this paper, the secrecy performance of a mixed free space optical (FSO)/radio frequency (RF) integrated satellite-high altitude platform (HAP) relaying networks for terrestrial multiusers with the existence of an eavesdropper is investigated. In this network, FSO is adopted to establish the link between the satellite and HAP for which it experiences Gamma-Gamma distributions under different detection schemes (i.e., heterodyne and intensity modulation direct detection). The transmission between the amplify-and-forward (AF) relaying HAP and terrestrial multiusers is through the RF and is modeled as shadowed-Rician fading distribution. Owning to broadcasting nature of RF link, it is assumed that an eavesdropper attempts to intercept the users’ confidential message, and the eavesdropper link is subjected to Rician distributions. Specifically, the closed-form expression for the system equivalent end-to-end cumulative distribution function is derived by exploiting the Meijer’s G and Fox’s H functions. Based on this expression, the exact closed-form expressions of the system connection outage probability, secrecy outage probability, and strictly positive secrecy capacity are obtained under the different detection schemes at HAP. Moreover, the asymptotic analyze of the system secrecy outage probability is provided to obtain more physical insights. Furthermore, the accuracy of all the derived analytical closed-form expressions is verified through the Monte-Carlo simulations. In addition, the impact of atmospheric turbulence, pointing errors, shadowing severity parameters, and Rician factor are thoroughly evaluated. Under the same system conditions, the results depict that heterodyne detection outperforms the intensity modulation direct detection.
TL;DR: A virtual model aided non-deterministic static analysis (including linear and nonlinear analyses) with polyphase uncertainty with a kernel-based machine learning technique, namely Twin Extended Support Vector Regression (T-X-SVR), is presented.
TL;DR: The results show that the parallel multi-hop hybrid system can effectively mitigate the negative impact of atmospheric turbulence and pointing errors and can significantly improve the system performance.
Abstract: Due to the influence of the atmospheric environment and pointing errors, the performance of free space optical communication is greatly limited. In this paper, we propose a parallel multi-hop hybrid free space optical (FSO)/radio frequency (RF) system to improve the system performance. The FSO sub-link and RF sub-link are modeled by Gamma–Gamma turbulence with pointing errors and Nakagami-m distributions, respectively. Based on the selective combination scheme, the probability density function (PDF) and cumulative distribution function (CDF) of the output signal-to-noise ratio (SNR) of the hybrid FSO/RF one-hop or direct link are obtained. Then, the PDF and CDF of the output SNR of the parallel multi-hop hybrid system are derived with the decoded forward (DF) protocol considered. Finally, the expressions of the average bit error rate (ABER) and outage probability are derived for the parallel multi-hop hybrid system, the hybrid FSO/RF direct link, and the FSO-only direct link. The results show that the parallel multi-hop hybrid system can effectively mitigate the negative impact of atmospheric turbulence and pointing errors and can significantly improve the system performance.
27 Mar 2022
TL;DR: Results show that the PDP can be well modeled by a single exponential decay with a statistically distributed decay-time constant, and it is shown that the generalized extreme value (GEV) distribution has better fit for the cumulative distribution function (CDF) of RMS delay spread than Lognormal distribution in LoS scenarios.
Abstract: The tunnel environment is a semi-enclosed space, the electromagnetic wave propagation characteristics are very different from the typical outdoor and indoor environments. Propagation model of electromagnetic waves in tunnels plays an important role in designing advanced wireless communication systems. In this paper, we firstly establish narrowband channel model for the tunnel in Line-of-sight (LoS) and obstructed line-of-sight (OLoS) scenarios, such as the path loss model, small-scale fading model. Then, we analyze the power delay profile (PDP) and root-mean-square (RMS) delay spread in the tunnel. Results show that the PDP can be well modeled by a single exponential decay with a statistically distributed decay-time constant. In addition, it is shown that the generalized extreme value (GEV) distribution has better fit for the cumulative distribution function (CDF) of RMS delay spread than Lognormal distribution in LoS scenarios. In general, RMS delay spreads in LoS scenarios is smaller than OLoS scenarios.
TL;DR: In this article , the secrecy performance of the free-space optical (FSO) system by considering different eavesdropping scenarios was numerically studied. And the secrecy outage probability (SOP) analytical expressions were derived at a high SNR regime.
Abstract: In this paper, we numerically study the secrecy performance of the free-space optical (FSO) system by considering different eavesdropping scenarios. More precisely, we considered three possible eavesdropping scenarios for Eve: 1) Eve is between Alice and Bob; 2) Eve and Bob are in the same receiving plane; 3) Eve is behind Bob. We adopt the Málaga (M)-distribution channel to model atmospheric turbulence due to the presence of link blockage while considering the non-zero boresight pointing error and path loss. To do so, we obtain a novel probability density function (PDF) and cumulative distribution function (CDF) under different eavesdropping scenarios, based on which we derived the secrecy outage probability (SOP) analytical expressions as well as their asymptotic expressions at a high SNR regime. We verified the results using Monte Carlo simulations, which showed that the parameters related to atmospheric turbulence and pointing errors, as well as the location of the eavesdropper, have different effects on different eavesdropping scenarios.