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Cognitive radios (CRs) are envisioned as a potential solution, to provide spectrum‐efficient communication for futuristic wireless communication systems like the Internet of Things (IoT) and others. This article examines the efficiency of CR's detection performance over the α−κ−F fading channel. The α−κ−F fading model is a generalized fading model intended to collectively quantify channel nonlinearity and shadowing effects. Therefore, the effect of channel nonlinearity and shadowing together on CR detection performance has been studied. New analytical formulas for the average probability of detection (APOD) for a single user and cooperative detection are obtained for energy detection (ED)–based spectrum sensing (SS). Additionally, to provide a deeper understanding of detection characteristics, expression for the area under the receiver operating characteristics is also obtained. The effectiveness of CR detection under various nonlinearity and shadowing effects is investigated using the developed analytical expressions, and the results indicate that performance degrades as channel impairments increase. At last, Monte Carlo simulations are employed to demonstrate that the obtained analytical expressions are valid. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this study was to adaptively optimise sensor networks using unmanned aerial vehicles to reduce information losses and ensure the minimum possible technical performance of information transmission channels in the face of a considerable number of architectural obstacles. In this study, experiments were conducted on data transmission via a wireless channel using Wi-Fi technology, where the access point was placed on an unmanned aerial vehicle. The study was conducted in complex architectural settings, using the 2.4 GHz and 5 GHz frequency bands to investigate the behaviour of radio channels and assess their effectiveness in real-world conditions. As a result of the study, a new method for estimating and optimising the energy parameters of radio channels was proposed, which accommodates the influence of a range of factors to improve the coverage efficiency of wireless sensor networks based on unmanned aerial vehicles. This method helped to partially solve the problem of information losses through adaptive optimisation of network coverage when influencing factors occur. The experimental models developed in this study allow estimating the signal distribution in space for sensor networks based on unmanned aerial vehicles, considering the influence of external factors, using fluctuation coefficients. The study also developed a mechanism for using a control device that allows measuring signal strength at any distance from the base station, providing flexibility and accuracy of assessment. The results showed a prominent level of measurement accuracy, with 95% reliability for an observation period of 20 seconds and an error of up to ±0.5 dBm. The total error of the methodology does not exceed 5%, which confirms the high reliability of the results and their compliance with real operating conditions. Thus, the findings of this study contribute to improving the efficiency and reliability of wireless sensor networks based on unmanned aerial vehicles, providing stable and high-quality connection in various operating conditions. [ABSTRACT FROM AUTHOR]

The growing popularity of online games has led to significant attention being paid to the satisfaction of their audiences, especially in terms of reducing energy consumption and increasing the quality of games. However, the hardware limitations of smart devices on which the games are played pose a major challenge to the quality of games. To resolve this issue, new technologies such as fog computing was proposed for offloading processing tasks. Because access to the fog environment is generally done through wireless channels, it is necessary to study the impact of wireless channel on the efficiency of fog computing. In addition to the wireless channel, the incurred delay on the servers located in the fog environment should also be considered for the evaluation of fog computing performance. In this paper, we examine the impact of wireless channel on offloading performance and show under what conditions using the fog environment can reduce the energy consumption of users' smart devices and also reduce latency in executing games. In order to calculate the delay in the fog servers, the order of servicing computational tasks is modeled by the service function chain and queueing theory is used to calculate the latency. Simulation results show that offloading does not always reduce energy consumption and delays, and the optimal decision regarding the assignment of tasks to the fog environment or its execution on the local device should take into account the conditions of wireless channel and the server capability located in the fog environment. [ABSTRACT FROM AUTHOR]

Nowadays, the Industry 4.0 concept and the Industrial Internet of Things (IIoT) are considered essential for the implementation of automated manufacturing processes across various industrial settings. In this regard, wireless sensor networks (WSN) are crucial due to their inherent mobility, easy deployment and maintenance, scalability, and low power consumption, among other benefits. In this context, the presented paper proposes an optimized and low-cost WSN based on ZigBee communication technology for the monitoring of a real manufacturing facility. The company designs and manufactures solar protection curtains and aims to integrate the deployed WSN into the Enterprise Resource Planning (ERP) system in order to optimize their production processes and enhance production efficiency and cost estimation capabilities. To achieve this, radio propagation measurements and 3D ray launching simulations were conducted to characterize the wireless channel behavior and facilitate the development of an optimized WSN system that can operate in the complex industrial environment presented and validated through on-site wireless channel measurements, as well as interference analysis. Then, a low-cost WSN was implemented and deployed to acquire real-time data from different machinery and workstations, which will be integrated into the ERP system. Multiple data streams have been collected and processed from the shop floor of the factory by means of the prototype wireless nodes implemented. This integration will enable the company to optimize its production processes, fabricate products more efficiently, and enhance its cost estimation capabilities. Moreover, the proposed system provides a scalable platform, enabling the integration of new sensors as well as information processing capabilities. [ABSTRACT FROM AUTHOR]

This paper proposes a novel modulated symbols-based one-time pad (SOTP) secure transmission scheme using physical layer keys. Unlike classical physical layer key generation and exclusive OR (XOR) encryption in the discrete binary space, we design a framework for modulated symbols-based one-time pad (OTP) encryption, where the cryptographic primitive and mathematical model of SOTP is given to build a practical cryptographic protocol. Compared with existing physical layer encryption (PLE) schemes, we provide rigorous proof that the framework can meet perfect secrecy and correctness requirements. In addition, we provide a specific scheme of physical layer OTP secure transmission for quadrature amplitude modulation (QAM) and phase-shift keying (PSK) symbols based on physical layer keys. This scheme realizes the unification of bit encryption and symbol encryption, which can adaptively select the quantization level according to the signal-to-noise ratio (SNR) to minimize the symbol error rate (SER). Further, we analyze the performance quantitatively and derive the closed-form expressions of SER, which indicates that the proposed scheme has a lower SER. Finally, simulation results verify that the proposed symbol-wise OTP secure transmission scheme can achieve perfect secrecy and high reliability. [ABSTRACT FROM AUTHOR]

Radio propagation environment plays a critical role in the performance of wireless communication systems, and understanding channel characteristics is vital for ensuring reliable communication links and optimizing system performance. Ray tracing is an effective method to investigate propagation characteristics in a complex environment, and how to quickly and accurately obtain environmental information needs to be solved. This paper presents dynamic environment reconstruction and ray tracing simulation in railway tunnel environment based on Simultaneous Localization and Mapping (SLAM) algorithm and Poisson reconstruction algorithm. Accurate channel parameters are obtained and analyzed based on ray tracing simulation. Both straight and curved tunnels are considered and investigated, and the results show the channel characteristics in complex railway tunnel environments. [ABSTRACT FROM AUTHOR]

Three-dimensional video (3DV) communication through wireless channels suffers from bit stream losses. Therefore, the efficient performance of 3DV transmission techniques over wireless networks is considerably a hot research topic. A high compression ratio must be introduced to meet future bandwidth restriction for optimized 3DV transmission. Unfortunately, the compressed 3DV bit streams are more sensitive and vulnerable to packet losses. In this paper, we suggest the application of chaotic Baker map interleaving with equalization and convolution coding for efficient discrete wavelet transform (DWT)-based singular value decomposition watermarked 3DV transmission over a multi-carrier code division multiple access wireless channels. Firstly, the compressed 3DV frames are watermarked using the DWT + SVD watermarking process. After that, chaotic interleaving is applied to minimize the channel effects on the transported bit streams, and it also adds an encryption level to the transported 3DV frames. Several experiments on different (DWT + SVD) watermarked 3DV frames have been tested to test the performance of the proposed hybrid techniques. The experimental results confirm that the received watermarked 3DV frames still have high peak signal-to-noise ratios, and efficient watermark extraction is possible. Thus, the main contribution of this paper is to present efficient hybrid techniques for secure 3DV communication. These proposed hybrid techniques efficiently protect the copyright of the 3DV streams to preserve both robustness and imperceptibility. Therefore, they have high quality, acceptable bit rates, low computational complexity, and adequate immunity to different types of multimedia attacks compared to the traditional techniques. [ABSTRACT FROM AUTHOR]

The paper proposes a method of two-dimensional joint estimation of information symbols and channel frequency response in OFDM communication systems based on the Kalman filter. The technique consists of two stages. In the first stage, estimates are iteratively calculated in the forward and backward directions concerning the array of processed data in the frequency dimension and on each of the subcarriers in the time domain. In the second stage, the obtained results are combined. The correlation properties of the channel are assumed to be known. The statistical simulation analyzes the proposed method using a model example. The results of estimating the channel parameters by the proposed method are compared with those obtained by known methods. The computational complexity of the developed method is determined. [ABSTRACT FROM AUTHOR]

The recently proposed technique, multiple input multiple output over-the-air computation (MIMO-AirComp), leverages the superposition property of the multiple access channel to efficiently integrate the communication and computation. This article proposes the MIMO-AirComp framework to compute the control signal of control systems. The proposed framework efficiently computes the target control signal by coordinating local pre-processing at each node, aggregation through the wireless channel, and post-processing at the controller. The simulation results show that the proposed MIMO-AirComp framework considerably improves the control performance by increasing the computation throughput compared to the conventional separated communication and computation approach. The proposed scheme with many nodes essentially suppresses the noise impact of both the wireless channel and the measurement, while the conventional one only reduces the impact of the channel noise. Specifically, the proposed scheme guarantees control stability in a network composed of high-noise wireless sensors, which is infeasible with the conventional approach. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The electromagnetic scattering of a meta-surface, formed by a honeycomb substrate or periodical arranged meta-materials, has great meanings to communication technologies. In a conventional treatment to investigate the properties of these interfaces, either a variational approach or series expansions had been applied, instead of estimating the effective permittivity or permeability by the mean value of its spatial discretized statistics due to spatiotemporal fusion. Following this, this study has re-examined the problem by the Statistic Estimation Averaging method (SEAm), through the transferred conditional structural Probability Density Functions (PDFs) to realize the structural determinations by homogenization. The parameters estimated by SEAm, which exploited the concept of a homogenized medium to express properties of a structural complex medium, has been verified of validity and accuracy by comparing with the measured results of a honeycomb structure. The method can be extended to estimate the parameters of an equivalent surface, such as randomly scattering from information metamaterials. As a new wireless communication relay technology, considering that information metamaterials can modulate the electromagnetic characteristics of communication links and wireless channels simultaneously by means of spatiotemporal sequence coding, the study also gives a preliminary proposition on state estimation method of information meta-surface, which would interpret the modulation effect of wireless channels caused by its inhomogeneity of antenna wavefront by statistical estimation average information entropy. [ABSTRACT FROM AUTHOR]

Metal cesium (Cs) vapor, released at an altitude in the upper atmosphere, generates an artificial space plasma cloud with high electron density. It can act as a scatter to realize radio communication across an over-the-horizon distance. A full-life model of radio propagation via an artificial plasma cloud is established based on its space–time evolution in this article. In addition, this model is verified by the sounding data of the rocket release experiment carried out in the United States. The multipath effect of plasma cloud scattering is studied by using ray tracing, and then, the coherent bandwidth is estimated for this spatial channel. Also, the theoretical channel model of artificial plasma cloud is established by using its space–time evolution and atmospheric wind field parameters. Considering common modulation modes and receiver noise levels, the potential communication performance is evaluated by using the proposed channel model, such as the transmission rate, the bit error rate (BER), and the available time for building up and maintaining communication links. It is shown that the maximal communication rate is up to 200 kb/s, BER overall maintains below 10−7, and the available time for a single release is about 30–60 min; for the case of this article, they are release mass of 2–10 kg, communication distances of 400–1200 km, and radio frequencies of 30–70 MHz at the VHF band. This demonstrates that the artificial channel can propagate radio waves at a much higher frequency, wider bandwidth, and higher rate than those of HF communication. Hopefully, it could be a solution to overcome the intolerable shortcoming and adverse effects on HF communication due to ionospheric disturbances especially in cases of maritime, emergency, and minimum communications [ABSTRACT FROM AUTHOR]

Cluster-based channel modeling has gradually become a trend in the development of a channel model, since it is a good compromise between accuracy and complexity. However, most of the existing clustering algorithms require prior knowledge of clusters, initialization, and threshold choices. An accurate and automatic cluster identification algorithm is therefore highly desirable for channel modeling. In this article, adaptive kernel-power-density (AKPD) and support vector machine-assisted AKPD (SVM-AKPD) algorithms are proposed. First, a new distance-based metric is proposed to calculate an adaptive-K for each multipath component (MPC), in which the AKPD can be used in scenarios where we have a complex distribution of MPCs, especially for the cluster with small MPCs. Furthermore, the SVM is applied in clustering by the full partition of MPCs’ feature space to overcome the limitation of the AKPD, where the MPCs lying at a large distance from the cluster centroids will be clustered into surrounding clusters when the clusters are closely spaced in the AKPD. Finally, the performance of the proposed AKPD and SVM-AKPD is validated with measured and simulated channels data at millimeter waveband, respectively. Both numerical simulations and experimental validation results are provided to demonstrate the effectiveness and robustness of the proposed algorithm. The proposed algorithms enable applications in multiple-input–multiple-output (MIMO) channels with no prior knowledge about the clusters, such as number and initial locations. It also does not need to adjust cluster parameters manually and can be implemented for cluster-based channel modeling with a fairly low complexity. [ABSTRACT FROM AUTHOR]

Two-way image communication in a wireless channel needs to be viable with channel properties such as transfer speed, energy-effective, time usage, and security because image capability consumes a huge space in the gadget and is quite effective. Is required in a manner. The figure goes through attacks. In addition, the quiesical issue for additional time of pressure is that the auxiliary interaction of pressure occurs through the dewar receiving extra time. To address these issues, compressed sensing emerges, which packs the image into hours of sensing, is generated in an expedient manner that reduces time usage and saves the use of data transfer capability, however Bomb in transmission. A variety of examinations cleared a way for dealing with security issues in compressive sensing (CS) through giving security as an alternative negotiation. In addition, univariate factors opted for CS as the issue of rearranging image quality is because of the aggregation of clutter. Along these lines related to the above issues, this paper proposed two-way image transmission to the Corvus Coron module, which presents an energy-effective with the CS model, as an inbuilt interaction in the CS transmission through the security framework. Receives what was designated as the pack-protected plot. Impeccable entertainment with the famous arbitrary network conjecture in CS. The result of the test is that the practical module presents energy-efficient and conserved transmission in the form of low error rate with low computational time. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Measurement Science & Instrumentation is the property of Journal of Measurement Science & Instrumentation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hardware components are an integral part of Hardware Define Radio (HDR) for seamless operations and optimal performance. On the other hand, Software Define Radio (SDR) is a program that does not rely on any hardware components for its performance. Both of the latter radio programmers utilize modulation functions to make their core components from signal processing viewpoint. The following paper concentrates on SDR based modulation and their performance under different modulations. The bit error rate (BER) of modulations such as PSK, QAM, and PSAM were used as indicators to test channel quality estimation in planar Rayleigh fading. Though it is not commonly used for channel fading, the method of the adder determines the regionally segmented channel fading. Thus, the estimation error of the channel change substantially reduces the performance of the signal, hence, proving to be an effective option. Moreover, this paper also elaborates that BER is calculated as a function of the sample size (signal length) with an average of 20 decibels. Consequently, the size of the results for different modulation schemes has been explored. The analytical results through derivations have been verified through computer simulation. The results focused on parameters of amplitude estimation error for 1dB reduction in the average signal-to-noise ratio, while the combined amplitude deviation estimation error results are obtained for a 3.5 dB reduction. [ABSTRACT FROM AUTHOR]

To stabilize closed-loop wireless control systems, the state-of-the-art approach receives the individual sensor measurements at the controller and then sends the computed control signal to the actuators. We propose an over-the-air controller scheme where all sensors attached to the plant transmit scaled sensing signals simultaneously to the actuator, and the actuator then computes the feedback control signal by scaling the received signal. The over-the-air controller essentially adopts the over-the-air computation concept to compute the control signal for closed-loop wireless control systems. In contrast to the state-of-the-art sensor-to-controller and controller-to-actuator communication approach, the over-the-air controller exploits the superposition properties of multiple-access wireless channels to complete the communication and computation of a large number of sensing signals in a single communication resource unit. Therefore, the proposed scheme can obtain significant benefits in terms of low actuation delay and low resource utilization with a simple network architecture that does not require a dedicated controller. [ABSTRACT FROM AUTHOR]

A technique for increasing the accuracy of ranging with the use of ultrawideband chaotic radio pulses is proposed for using in wireless sensor networks. As a result of performed experimental bench tests, it is shown that the level of the relative ranging error falls inside the limits of 5–9%. [ABSTRACT FROM AUTHOR]

Purpose: The manufacturing of intelligent and secure visual data transmission over the wireless sensor network is key requirement nowadays to many applications. The two-way transmission of image under a wireless channel needed image must compatible along channel characteristics such as band width, energy-efficient, time consumption and security because the image adopts big space under the device of storage and need a long time that easily undergoes cipher attacks. Moreover, Quizzical the problem for the additional time under compression results that, the secondary process of the compression followed through the acquisition consumes more time. Design/methodology/approach: Hence, for resolving these issues, compressive sensing (CS) has emerged, which compressed the image at the time of sensing emerges as a speedy manner that reduces the time consumption and saves bandwidth utilization but fails under secured transmission. Several kinds of research paved path to resolve the security problems under CS through providing security such as the secondary process. Findings: Thus, concerning the above issues, this paper proposed the Corvus corone module two-way image transmission that provides energy efficiency along CS model, secured transmission through a matrix of security under CS such as inbuilt method, which was named as compressed secured matrix and faultless reconstruction along that of eminent random matrix counting under CS. Originality/value: Experimental outputs shows intelligent module gives energy efficient, secured transmission along lower computational timing also decreased bit error rate. [ABSTRACT FROM AUTHOR]

Designing a spectrally efficient wireless channel requires a comprehensive understanding of its time and frequency varying characteristics, making it a stochastic medium of communication. These characteristics become more challenging to cater at the receiving terminal in a multipath transmission. This is because of the fading effect and Doppler shift of the transmitted frequency, specifically in cellular mobile radio systems and vehicle to vehicle communications. This paper presents the modeling, simulation, and then characterization of a cellular mobile radio multipath channel over its time and frequency varying fading gain. For this purpose, a discrete-time Finite Impulse Response (FIR) type filter of such a channel is designed, modeled, and simulated using time and frequency varying characteristics of the received signal. The simulated channel response is further analyzed in terms of coherence bandwidth, coherence time, delay spread, Doppler spread, and symbol time. [ABSTRACT FROM AUTHOR]

In this brief we propose a space-time trellis code scheme based on three-dimensional chaotic attractors. The chaotic trajectories are represented by the symbolic dynamics generated by a labeled Poincaré section and are transmitted by multiple antennas, defining a chaos-based space-time trellis code (CB-STTC). This code is defined by a finite state encoder that maps information sequences to restricted sequences satisfying the dynamics of the attactor. We also propose a neural network architecture capable of learning how to decode the CB-STTC. Finally, the frame error rate of the proposed CB-STTC is analyzed with maximum likelihood and neural network decoding. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nowadays, the Industrial Internet of Things (IIoT), plays an important role in transforming industrial environment by opening up a new area for economic growth and competitiveness in digital Industry 4.0. Using intelligent communication system based on IIoT, will help factories to obtain better profits in the industrial manufacturing markets. For this purpose, this article presents performances in terms of binary error rate of a wide-band IIoT multi-users (or sensors) system under an industrial medium. This medium is simulated as a fading channel including industrial noise, through which the robustness of our system will be studied and improved. This multi-users system is based on IDWPT and DWPT for many-to-one applications. To face the harshness of the industrial environment, an error-correcting code is added to the architecture to improve its robustness. Two error-correcting codes are used, convolutional coding and RS code for 8, 16 and 32 multi-sensors system. This will lead to a comparative analysis of the performance between this two coding techniques. [ABSTRACT FROM AUTHOR]

This article proposes an extension to the $\eta - \mu $ fading model by including a parameter that quantifies the clustering imbalance between in-phase and quadrature components. The inclusion of such a parameter renders the model enormously flexible, extending its reach of application in a wider range of scenarios. Despite the inclusion of an additional parameter, the equations obtained remain as mathematically tractable as those for the original $\eta - \mu $ model. Several new closed-form expressions for important statistics are then obtained, including: (i) probability density functions for both envelope and phase; (ii) cumulative distribution functions for both envelope and phase; (iii) arbitrary moments for the envelope; (iv) moment generating function for the envelope; (v) average bit error rate for coherent binary systems; (v) level crossing rate, average fading duration, and phase crossing rate; and (vi) several other joint distributions encompassing envelope, phase, and their respective time derivatives. It is noteworthy that many of the closed-form formulations presented here are not available even for the simple $\eta - \mu $ model. [ABSTRACT FROM AUTHOR]

This paper reports the technique devised to evaluate fluctuations in the main parameters for a wireless channel of the 802.11 standard based on the confidence regression interval. Underlying such a technique is the use of mathematical ratios of the relationship among the statistical probability, variance, and fluctuation level. It should be noted that this technique could be used when technically diagnosing the 802.11x standard wireless networks at the stages of their design and operation. Applying the proposed technique for the estimation models of the main channel parameters makes it possible to derive an estimate of fluctuation intervals without the need to process large arrays of measurement results. This greatly reduces the time of obtaining the result from diagnosing by involving monitoring algorithms. An expression for the statistical relation between fluctuations in the main parameters of the 802.11 standard wireless channel was obtained on the basis of the proposed mathematical ratios, which makes it possible to evaluate fluctuations of the information parameter based on the fluctuations of an energy one and vice versa. This is relevant when assessing the effective speed of information transmission based on measuring the signal strength at the receiver input using monitoring algorithms. The analysis of the reported results and their comparison with empirical studies have shown that based on the interrelation between the main channel parameters with a regression confidence interval it is possible to determine the level of fluctuations based on the confidence probability. The dependence of a fluctuation level on the variances and confidence intervals of regression models has also been established. With a probability of 0.85, the fluctuations have been obtained for direct visibility and at a minimum number of interferences while a probability of 0.97 shows the impact of a multipath wave propagation factor in the premises. [ABSTRACT FROM AUTHOR]

This paper studies the impact of unmanned aerial vehicle (UAV) wobbling on the coherence time of the wireless channel between UAVs and a ground user equipment (UE), using a Rician multi-path channel model. We consider two different scenarios for the number of UAVs: (i) single UAV scenario (SUS), and (ii) multiple UAV scenario (MUS). For each scenario, we model UAV wobbling by two random processes, i.e., the Wiener and sinusoidal processes, and characterize the channel autocorrelation function (ACF) which is then used to derive the coherence time of the channel. For the MUS, we further show that the UAV-UE channels for different UAVs are uncorrelated from each other. A key observation in this paper is that even for small UAV wobbling, the coherence time of the channel may degrade quickly, which may make it difficult to track the channel and establish a reliable communication link. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A method of estimating the effective data rate in channels of the Standard 802.11 was proposed. It provides for the measurement of the main energy parameter using the software and hardware of the subscriber device. This method is based on the empirical models of statistical relationships between the main parameters of the channel which are obtained on the basis of experimental studies using monitoring algorithms. The solutions obtained during the implementation of this method make it possible to take into account the maximum possible number of destabilizing factors and significantly reduce the time of assessment of the effective data rate. It should be noted that this method can be used for technical diagnostics of wireless networks of Standards 802.11x at the stages of network design and operation. It was established that when using the coefficient of energy efficiency, a significant error in the displacement of the points of intersection of the linear and logarithmic mathematical model occurs. This can lead to a discrepancy between the mathematical estimates of the effective data rate and real values. The statistical relationship gives a smaller error; however, it increases requirements for empirical studies to obtain the maximum possible reliability. One of the features of the proposed method is the reliability of assessment of the effective data rate. This reliability depends on three main factors: accuracy of assessing the results based on which the mathematical model was obtained; estimation of fluctuation intervals and characteristics of the Standard 802.11 equipment of different manufacturers. The last factor can be considered as a disadvantage that involves the creation of a database of parameters of the model of statistical relationship for different devices with correction coefficients. [ABSTRACT FROM AUTHOR]

Summary: Faults are natural for any practical system including photovoltaic (PV) power generation systems that need to be diagnosed accordingly to maximize its efficiency. However, faults can be rectified only if they are diagnosed correctly. Therefore, a credible and reliable diagnosis is required for maintenance of the system. In this paper, independent component analysis (ICA)‐based wireless fault diagnosis technique is proposed for solar PV systems. ICA enables us to communicate without having any prior information about the signals and the wireless channel. The proposed technique can diagnose faults related to electrical failures, climatic impacts, variable irradiance, and irregular cell temperature. Effectiveness of the proposed technique is evaluated through extensive simulations utilizing practical data. [ABSTRACT FROM AUTHOR]

Summary: Communication systems and radar systems generally face problems caused by time‐varying motion, especially in the case of complex radio wave propagation in cities. Therefore, it is necessary to establish a suitable channel model to simulate the system to deal with these problems. This paper refers to the MIMO space‐time channel model in the 3rd Generation Partnership Project (3GPP) technical standard and proposes a method for modeling and simulating time‐varying motion in a MIMO downlink system according to the characteristics of the wireless channel and the transmission mode. The transmission function in MIMO downlink is derived to calculate the different Doppler frequency shift in the model based on 3GPP. By integrating ADS with Matlab software, environmental parameters and correlation coefficients can be manually set to simulate the downlink. During the simulation process, different modulation model bandwidths and channel conditions are set, and the configuration of the antenna parameters changes accordingly. Finally, the differences of simulation results are analyzed. [ABSTRACT FROM AUTHOR]

The traditional optical fiberchannel-based key distribution method is limited by the optical fiber resources and construction cost, and it is difficult to meet the security enhancement requirements of the access side massive power service terminals, especially the mobile terminals. In this respect, a wireless channel-based quantum key distribution system was proposed, which was suitable for mass service terminals of power systems. Based on the wireless access requirements of mass service terminals in power system, the overall design of power quantum key distribution system based on wireless channel was given. The functional modules and execution flow of the power quantum key distribution system based on wireless channel were analyzed in detail from three aspects: quantum security service control platform, quantum key storage management platform and massive power service terminal platform. On this basis, combined with the typical power service such as electricity information collection and mobile office, the advantages and prospects of the quantum channel distribution system based on wireless channel applied to the terminal scenario of massive power service were comprehensively analyzed. [ABSTRACT FROM AUTHOR]

In a wireless network, a basestation transmits data to mobiles at time-varying, mobile-dependent rates due to the ever changing nature of the communication channels. In this article, we consider a wireless system in which the channel conditions and data arrival processes are governed by an adversary. We first consider a single server and a set of users. At each time step t, the server can only transmit data to one user. If user i is chosen, the transmission rate is ri (t). We say that the system is (w, ε)-admissible if in any window of w time steps the adversary can schedule the users so that the total data arriving to each user is at most 1 -- ε times the total service it receives. Our objective is to design online scheduling algorithms to ensure stability in an admissible system. We first show, somewhat surprisingly, that the admissibility condition alone does not guarantee the existence of a stable online algorithm, even in a subcritical system (i.e., ε > 0). For example, if the nonzero rates in an infinite rate set can be arbitrarily small, then a subcritical system can be unstable for any deterministic online algorithm. On a positive note, we present a tracking algorithm that attempts to mimic the behavior of the adversary. This algorithm ensures stability for all (w, ε)-admissible systems that are not excluded by our instability results. As a special case, if the rate set is finite, then the tracking algorithm is stable even for a critical system (i.e., ε = 0). Moreover, the queue sizes are independent of ε. For subcritical systems, we also show that a simpler max weight algorithm is stable as long as the user rates are bounded away from zero. The offline version of our problem resembles the problem of scheduling unrelated machines and can be modeled by an integer program. We present a rounding algorithm for its linear relaxation and prove that the rounding technique cannot be substantially improved. [ABSTRACT FROM AUTHOR]

A number of new results aiming at facilitating the use of the $\alpha $ - $\eta $ - $\kappa $ - $\mu $ fading model are presented. These results include: 1) fast convergent, with no recursions, series representations for the envelope probability density function (PDF) and cumulative distribution function (CDF); 2) higher order moments of the envelope; 3) moment generating function (MGF) of the envelope; 4) asymptotic behavior of the envelope PDF and also of the envelope CDF; 5) a procedure for parameter estimation; 6) new closed-form expressions for particular cases of the envelope distribution; 7) new mathematical identity for the generalized Laguerre polynomial and the generalized hypergeometric function; and 8) approximate, but tight, series representation for the phase PDF. As application examples, the following are given: 1) outage probability; 2) outage capacity; 3) amount of fading; and 4) bit error rate, for which the asymptotic behavior is also presented. [ABSTRACT FROM AUTHOR]

This study proposes a new method to estimate room shape using radio waves. Unlike existing heuristic methods, the proposed method uses accumulated radio channel data and the neural network to predict room shapes. The radio channel data is generated by three dimensional (3D) ray tracing simulation and actual measurements. The neural network used the channel data for the training process. After training the neural network, we evaluated the performance variation resulting from changes in the channel environment parameters used in the neural network training, the size of the room, hyperparameters of the neural network, and the location of the transceivers. The results showed that better performance was observed when more sets of channel parameters were used as inputs to the neural network. In addition, the results obtained from measurements show that the estimation of the room shape through the neural network works well not only in the simulation but also in the real world. [ABSTRACT FROM AUTHOR]

In this paper, we study upper and lower bounds for contention resolution on a single hop fading channel; i.e., a channel where receive behavior is determined by a signal to interference and noise ratio equation. The best known previous solution solves the problem in this setting in O (log 2 n / log log n) rounds, with high probability in the system size n. We describe and analyze an algorithm that solves the problem in O (log n + log R) rounds, where R is the ratio between the longest and shortest link, and is a value upper bounded by a polynomial in n for most feasible deployments. We complement this result with an Ω (log n) lower bound that proves the bound tight for reasonable R. We note that in the classical radio network model (which does not include signal fading), high probability contention resolution requires Ω (log 2 n) rounds. Our algorithm, therefore, affirms the conjecture that the spectrum reuse enabled by fading should allow distributed algorithms to achieve a significant improvement on this log 2 n speed limit. In addition, we argue that the new techniques required to prove our upper and lower bounds are of general use for analyzing other distributed algorithms in this increasingly well-studied fading channel setting. [ABSTRACT FROM AUTHOR]

The objective of the research is to develop information models in order to improve the efficiency of evaluating the parameters of the wireless channels in 802.11 standard. A feature of the information model of the wireless channel of 802.11 standard is an opportunity to evaluate the efficiency of transferring the information block taking into account the complete packet and frame transmission cycle in the event of errors in frames. In addition, the model accounts for the existence of other subscribers in the network and the mechanism of competition for the physical resource of the frequency channel. It has been established that channel efficiency is mostly affected by the presence of destabilizing factors in the channel, which lead to an increase in the number of service information and an increase in the transmission cycle due to the creation of reciprocal queries. [ABSTRACT FROM AUTHOR]

Copyright of Application Research of Computers / Jisuanji Yingyong Yanjiu is the property of Application Research of Computers Edition and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Path loss prediction is of great significance for the performance optimization of wireless networks. With the development and deployment of the fifth-generation (5G) mobile communication systems, new path loss prediction methods with high accuracy and low complexity should be proposed. In this paper, the principle and procedure of machine-learning-based path loss prediction are presented. Measured data are used to evaluate the performance of different models such as artificial neural network, support vector regression, and random forest. It is shown that these machine-learning-based models outperform the log-distance model. In view of the fact that the volume of measured data sometimes cannot meet the requirements of machine learning algorithms, we propose two mechanisms to expand the training dataset. On one hand, old measured data can be reused in new scenarios or at different frequencies. On the other hand, the classical model can also be utilized to generate a number of training samples based on the prior information obtained from measured results. Measured data are employed to verify the feasibility of these data expansion mechanisms. Finally, some issues for future research are discussed. [ABSTRACT FROM AUTHOR]

Channel effects can severely degrade performance and reliability of a wireless communication system if they are not taken into account. An accurate characterization is indispensable for the proper design and parametrization of such data links. In this paper, the focus is on aircraft to ground station channel sounding and characterization to lay the foundation for unmanned aerial vehicle (UAV) control and non-payload communication (CNPC) link designs. After a comprehensive review of related work, an introduction into the implemented channel sounding principle with the aid of a custom-made sounder is given, followed by a detailed description of the two measurement campaigns at Ingolstadt/Manching airport, Germany. The obtained large-scale fading results are presented, including shadowing and antenna misalignment effects. Then, small-scale fading is discussed by means of K-factors, delay, and Doppler spread statistics. For all evaluations, the recorded data set has been classified to work out and compare the characteristics of typical phases of UAV operation. Implications of the presented analyses on the parametrization of CNPC links are mentioned as well. [ABSTRACT FROM AUTHOR]

The Three-Dimensional Video (3DV) contains diverse video streams taken by different cameras around an object. Thence, it is an imperative assignment to fulfill efficient compression to match the future resource limitations, whilst preserving a decisive reception 3DV quality. The efficient 3DV communication over wireless networks has become a recent considerable hot issue due to the restricted resources and the presence of severe channel errors. The high-rate 3DV encoding and transmission over mobile or Internet are vulnerable to packet losses due to the existence of heavy channel losses and limited bandwidth. Therefore, this paper presents efficient multi-stage error control algorithms for reliable 3DV transmission over error-prone wireless channels. At the encoder, the error resilience schemes of context adaptive variable length coding, slice structured coding, and explicit flexible macro-block ordering are utilized. At the decoder, a joint approach of a directional interpolation error concealment algorithm and a directional textural motion coherence algorithm is proposed to conceal the corrupted color frames. For the concealment of the lost depth frames, an encoder independent decoder dependent depth-assisted error concealment algorithm is suggested. Moreover, the weighted overlapping block motion and disparity compensation algorithm is exploited to choose the candidate concealment Motion Vectors (MVs) and Disparity Vectors (DVs). Furthermore, an improved recursive Bayesian filtering algorithm is utilized as a refinement stage to smooth the remaining errors in the previously selected candidate MVs and DVs for achieving better 3DV quality. Simulation results on several 3DV sequences show that the proposed algorithms achieve adequate objective and subjective 3DV quality performance at severe packet loss rates compared to the state-of-the-art algorithms. [ABSTRACT FROM AUTHOR]

We study a general type of multiple-input multiple-output (G-MIMO) relay channels, which consist of two groups (A and B) of source nodes and one relay node. Both groups have arbitrarily many source nodes each of which is in turn equipped with an arbitrary number of antennas. A G-MIMO relay channel engages in two-way transmission of independent information via the relay node. We obtain a tight upper bound on the total degrees of freedom (DoF) for such G-MIMO relay channels. Under the reasonable assumption that the number of antennas at the relay node is no more than the total number of antennas of either Group A or B, we design an efficient transmission scheme to achieve the upper bound by using techniques of signal alignment and joint transceiver design for interference cancellation. At the end of the paper, we propose a future research topic to quantify the relationship between graded levels of network security and the corresponding DoF of the G-MIMO relay channels. [ABSTRACT FROM AUTHOR]

Recent research in the field of 3-D system integration has looked to the use of inductive-coupling links (ICLs) to provide vertical connectivity without incurring the inflated fabrication and testing costs associated with through-silicon vias. For power-efficient ICL design, optimization of the utilized physical inductor geometries is essential, but currently must be performed manually in a process that can take several hours. As a result, the generation of optimized inductor designs poses a significant challenge. In this paper, we address this challenge in three main contributions: 1) a novel, nonuniform planar inductor layout that exhibits enhanced performance when compared with conventional uniform inductors; 2) a rapid solver for evaluating inductor layouts; and 3) a high-speed optimization algorithm for determining best performing coil pairs. These three contributions are combined as a CAD tool for optimization of ICLs for 3-D-ICs (COIL-3-D). Results demonstrate that COIL-3-D achieves an average accuracy within 7.8% of finite-element tools consuming a small fraction of the time ($1.5\times 10^{-3}$ %), significantly ameliorating the design of ICL-based 3-D-ICs. We also demonstrate that using COIL-3-D to optimize ICL inductor layouts can yield significant performance (up to 41.5% bandwidth improvement) and power (up to 8.1% power improvement) benefits, when compared with layouts used in prior ICL implementations. For these reasons, this paper unlocks new potential for low-cost, power-efficient 3-D integration using ICLs. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Data Acquisition & Processing / Shu Ju Cai Ji Yu Chu Li is the property of Editorial Department of Journal of Nanjing University of Aeronautics & Astronautics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Over the past few years, the modeling of wireless channels for radio wave propagation over the sea surface has drawn the attention of many researchers. Channel models are designed and implemented for different frequencies and communication scenarios. There are models that emphasize the influence of the height of the evaporation duct in the marine environment, as well as models that deal with different frequencies (2.5, 5, and 10 GHz, etc.) or the impact of various parameters, such as antenna height. Despite the increasing literature on channel modeling for the over-the-sea marine environment, there is no comprehensive study that focuses on key concepts that need to be considered when developing a new channel model, characteristics of channel models, and comparative analysis of existing works along with their possible improvements and future applications. In this paper, channel models are discussed in relation to their operational principles and key features, and they are compared with each other in terms of major characteristics and pros and cons. Some important insights on the design and implementation of a channel model, possible applications and improvements, and challenging issues and research directions are also discussed. The main goal of this paper is to present a comparative study of over-the-sea channel models for radio wave propagation, so that it can help engineers and researchers in this field to choose or design the appropriate channel models based on their applications, classification, features, advantages, and limitations. [ABSTRACT FROM AUTHOR]

In the fifth‐generation mobile communications networks, several resource allocation techniques have been used, such as static allocation and dynamic algorithms (greedy or matching theory); this work proposes a new subcarrier allocation scheme based on the evaluation of the instantaneous behaviour of the wireless channel using the condition number of the channel matrix H. Simulation results reveal that the proposed scheme increases the total sum rate of the system, compared to their predecessors. [ABSTRACT FROM AUTHOR]

The three-dimensional video (3DV) is composed of variable-length stream sequences captured via diversified cameras surrounding an object. Thus, it is an urgent task to accomplish sufficient encoding to be compatible with incoming bandwidth demands, while achieving a recommended 3DV reception performance. In the 3DV compression framework, the lost macro-blocks (MBs) might propagate into the following frames and the adjoining views. Therefore, it is obligatory to avoid error propagation by concealing the corrupted MBs at the decoder through the utilization of appropriate post-processing error concealment (EC) techniques. The existing EC algorithms fundamentally exploit the temporal, inter-view, and spatial matching within the 3DV frames and views to reconstruct the disparity vectors (DVs) and motion vectors (MVs) of the corrupted MBs. Unluckily, in the state of high severe corruptions and heavily erroneous MBs, these concealment algorithms are predominantly unreliable and might give unreliable 3DV quality. Thence, in this work, we suggest the utilization of the outer block boundary matching algorithm to estimate the MVs and the directional interpolation EC algorithm to estimate the DVs of the erroneous MBs. After that, the Bayesian Kalman filter (BKF) is employed because of its efficiency to filter out the inherent errors in the previously predicted DVs and MVs to accomplish better 3D video performance. Experimental results on standard 3DV sequences demonstrate that the suggested BKF-based EC scheme is more powerful with heavy losses. It subjectively and objectively outperforms the traditional concealment techniques at severely random and bursty packet loss rates (PLRs). [ABSTRACT FROM AUTHOR]

Multi‐hop wireless network (MHWN) can be easily attacked by jammers for its shared nature and open access to the wireless medium. Jamming attack may pose a significant threat to MHWN by occupying wireless channel used by legitimate users. A number of anti‐jamming countermeasures have been put forward to eliminate the impact of communication disruption caused by jamming attacks. As an important building block of anti‐jamming strategies, jammer localisation attracts much attention in recent years and several algorithms have been presented. However, how to locate multiple co‐existing jammers receives little attention, and the efficiency and accuracy of the existing methods are still unsatisfactory. In this study, the authors focus on the localisation of sequential opening multi‐jammers and put forward the multi‐jammers localisation algorithm based on time series analysis (MLTSA) algorithm. The main process of MLTSA consists of four steps: detection of jamming attack, collection of received jamming signal strength, anomaly detection and separation of nodes, the existence determination and localisation of jammers. Finally, a series of simulation experiments are conducted to evaluate the correctness and effectiveness of the proposed algorithm. Experimental results show that the localisation accuracies of MLTSA are better than those of several state‐of‐the‐art solutions. [ABSTRACT FROM AUTHOR]