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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

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]

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.

The rapid development of wireless local area network technology has brought about new challenges that significantly affect the communication quality of wireless channels.Wireless channel quality is crucial for guiding routers in managing sudden congestion and selecting appropriate channels.A set of solutions using channel available throughput as an indicator was designed.Firstly, invasive data collection methods were used to collect channel data, and an artifical neural network was trained to estimate the available throughput of the channel at the current time.Subsequently, non-invasive data collection methods were utilized to collect channel data, and an improved recurrent neural network model was employed to predict the available throughput of the channel for a future period.Experiments on the real data show that the scheme can effectively estimate and predict the available throughput of the channel, providing guidance for router decisions.

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]

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]

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]

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]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology 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 conducted measurement campaigns at home and abroad were presented.Meanwhile, proposals and standard channel models from the international standardization organization were reviewed.The propagation characteristics of massive MIMO wireless channels were investigated based on the indoor and outdoor measurements.Moreover, the traditional and novel methods of channel modeling were analyzed.Finally, open research issues were presented.

Wireless communication under 1 GHz is suitable for Internet of Things (IoT) applications due to larger coverage capability with less power consumption. Bearing in mind that people and elements contained in the environment can cause variations in the channel, this paper aims to evaluate the effect of the presence of people on a 900-MHz indoor narrowband wireless channel, as we characterize the small-scale phenomena. With the increase in the number of people, a greater variation in the communication channel was noticed, which is reflected in the parameters of the probability distributions used in the characterization of the random part of the signal. In addition, second-order statistics were used to analyze the data and an adherence test was applied to confirm the behavior of the signal in relation to the distributions.

The development of multiple cultural and social related activities, such as shows related with the performing arts, conferences or presentations rely on facilities such as auditoriums, theatres and conference sites, which are progressively including multiple technological features in order to enhance user experience. There are still however situations in which user experience is limited owing to lack of environment adaption, such as people with disabilities. In this sense, the adoption of Context Aware paradigms within auditoriums can provide adequate functionalities in order to comply with specific needs. This work is aimed at demonstrating the feasibility in enhancing user experience (e.g., improving the autonomy of disabled people) within auditorium and theatre environments, by means of an Augmented Reality (AR) device (HoloLens smart glasses) with wireless system integration. To carry out the demonstration, different elements to build AR applications are described and tested. First, an intensive measurement campaign was performed in a real auditorium in the city of Pamplona (Baluarte Congress Center) in order to evaluate the feasibility of using Wi-Fi enabled AR devices in a complex wireless propagation scenario. The results show that these environments exhibit high levels of interference, owing to the co-existence and non-coordinated operation of multiple wireless communication systems, such as on site and temporary Wi-Fi access points, wireless microphones or communications systems used by performers, staff and users. Deterministic wireless channel estimation based in volumetric 3D Ray Launching have been obtained for the complete scenario volume, in order to assess quality of service metrics. For illustration purposes, a user-friendly application to help hearing impaired people was developed and its main features were tested in the auditorium. Such an application provides users with a 3D virtual space to visualize useful multimedia content like subtitles or additional information about the show, as well as an integrated call button.

Recent standardization of portions of the millimeter-wave (mm-wave) band for fifth-generation (5G) operation has called for further research on how short-term fading behaves in that unexplored part of the spectrum. With such a target, this paper reports on a thorough measurement campaign conducted in an indoor environment characterized by rich-multipath scattering, a part of a modern building, with floor and ceiling constructed of reinforced concrete over steel plates with wood and plasterboard-paneled walls. Particularly, measurements have been performed in a variety of scenarios, under line-of-sight (LoS) and non-line-of-sight (nLoS) conditions, for a wide range of frequencies, namely from 25 to 40 GHz- a span of 15 GHz- therefore, including 26, 28 and 39 GHz. First and second order statistics of representative fading models, namely Rayleigh, Rice, Nakagami, folded normal, ${\alpha } $ - ${\mu } $ , ${\eta } $ - ${\mu }$ , ${\kappa } $ - ${\mu } $ , and ${\alpha } $ - ${\eta } $ - ${\kappa } $ - ${\mu } $ have been investigated. The metrics used in the analysis were the normalized mean square error (NMSE), the Kolmogorov-Smirnov (KS), and the Akaike information criterion (AIC). Additionally, the study of the ${\kappa } $ - ${\mu } $ model is advanced, in which new, exact, simple closed-form expressions for probability density function, cumulative distribution function, and level crossing rate are derived for some particular cases, namely for ${\mu = n+ 1/2}$ in which ${n\in {{\mathbb {N}}}}$ .

Halangan pada Line of Sight (LOS) dapat menyebabkan difraksi (pembelokan), refleksi (pemantulan), dan scattering (penghamburan) pada sinyal informasi dimana akan mengurangi kualitas sinyal informasi yang diterima pada sisi penerima. Hal tersebut mengakibatkan adanya sifat konstruktif maupun destruktif pada sinyal di sisi penerima. Contoh sifat destruktif yang sering terjadi yakni fading dan delay. Sistem penerima correlation receiver diimplementasikan guna mengatasi masalah yang timbul akibat efek dari multipath fading. Untuk memperoleh sinyal dengan nilai error minimum, maka diperlukan analisis terkait proses transmisi pada masing-masing komponen multipath. Hasil analisis diperoleh bahwa unjuk kerja dari Kode PN (Pseudo Noise) pada kanal frequency selective fading yang lebih baik adalah variasi komponen multipath = 3 dibandingkan dengan variasi komponen multipath = 6 dan yang paling buruk adalah variasi komponen multipath = 7. Hal ini dibuktikan dengan melihat nilai Bit Error Rate (BER) saat Energy Per Bit To Noise Power Spectral Density Ratio (Eb/No) = 10 dengan komponen multipath = 3 memiliki nilai BER 0,00368, sedangkan komponen multipath = 6 dan komponen multipath = 7 memiliki nilai BER berturut – turut adalah 0,00386 dan 0,00507. Berdasarkan hasil analisis tersebut dapat diambil simpulan bahwa jumlah komponen multipath yang ada berpengaruh terhadap kualitas sinyal yang diterima.

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.

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]

The traditional process of finding a vacant parking slot is often inefficient: it increases driving time, traffic congestion, fuel consumption and exhaust emissions. To address such problems, smart parking systems have been proposed to help drivers to find available parking slots faster using latest sensing and communications technologies. However, the deployment of the communications infrastructure of a smart parking is not straightforward due to multiple factors that may affect wireless propagation. Moreover, a smart parking system needs to provide not only accurate information on available spots, but also fast responses while guaranteeing the system availability even in the case of lacking connectivity. This article describes the development of a decentralized low-latency smart parking system: from its conception, design and theoretical simulation, to its empirical validation. Thus, this work first characterizes a real-world scenario and proposes a fog computing and Internet of Things (IoT) based communications architecture to provide smart parking services. Next, a thorough analysis on the wireless channel properties is carried out by means of an in-house developed deterministic 3D-Ray Launching (3D-RL) tool. The obtained results are validated through a real-world measurement campaign and then the communications architecture is implemented by using ZigBee sensor nodes. The implemented architecture also makes use of Bluetooth Low Energy beacons, an Android app, a decentralized database and fog computing gateways, whose performance is evaluated in terms of response latency and processing rate. Results show that the proposed system is able to deliver information to the drivers fast, with no need for relying on remote servers. As a consequence, the presented development methodology and communications evaluation tool can be useful for future smart parking developers, which can determine the optimal locations of the wireless transceivers during the simulation stage and then deploy a system that can provide fast responses and decentralized services.

In this paper, an enhancement of a hybrid simulation technique based on combining collaborative filtering with deterministic 3D ray launching algorithm is proposed. Our approach implements a new methodology of data depuration from low definition simulations to reduce noisy simulation cells. This is achieved by processing the maximum number of permitted reflections, applying memory based collaborative filtering, using a nearest neighbors' approach. The depuration of the low definition ray launching simulation results consists on discarding the estimated values of the cells reached by a number of rays lower than a set value. Discarded cell values are considered noise due to the high error that they provide comparing them to high definition ray launching simulation results. Thus, applying the collaborative filtering technique both to empty and noisy cells, the overall accuracy of the proposed methodology is improved. Specifically, the size of the data collected from the scenarios was reduced by more than 40% after identifying and extracting noisy/erroneous values. In addition, despite the reduced amount of training samples, the new methodology provides an accuracy gain above 8% when applied to the real-world scenario under test, compared with the original approach. Therefore, the proposed methodology provides more precise results from a low definition dataset, increasing accuracy while exhibiting lower complexity in terms of computation and data storage. The enhanced hybrid method enables the analysis of larger complex scenarios with high transceiver density, providing coverage/capacity estimations in the design of heterogeneous IoT network applications.

In the battlefield, we often don't know the parameters about enemy wireless communication system. Therefore, we need to use electronic reconnaissance equipment to search, intercept, identify and analyze enemy wireless communication signal. However, the exciting electronic reconnaissance methods can only detect signal layer parameters such as signal carrier frequency and bandwidth, and cannot obtain more information. In order to improve the reconnaissance ability, we propose a novel communication protocol classification algorithm based on long short-term memory (LSTM) and deep belief network (DBN). We first introduce the DBN, then simulates communication protocol classification method based on DBN. In order to improve the performance, we optimize the method. We uses the LSTM to pre-process the data to extract the feature firstly. Then we make the feature as the input of DBN to classify the communication protocol. Finally we make simulation to verify the effectiveness of the proposed algorithm. Simulation results show that the proposed algorithm has very good performance to classify the communication protocol.

Wireless channel scenarios identification is of pivotal significance for dedicated wireless communication design, especially for the heterogeneous network covering rich propagation environments. In this paper, the identification problem is investigated by machine learning approaches. To enhance the identification performance, some preprocessing methods, mainly referring to the data normalization and dimension reduction, are adopted. Then, both supervised and unsupervised learning algorithms, including k-nearest neighbor (k-NN), support vector machine (SVM), k-means, and Gaussian mixture model (GMM) are used to realize the scenarios identification, respectively. Finally, the identification performance of these four approaches are validated both on the actual measured HSR wireless channel data sets and the QuaDRiGa channel emulation platform with the ability of multiple scenarios emulation. Most of the results indicate that k-NN and SVM approaches can achieve an accuracy over 90%. As for those two unsupervised learning approaches, the GMM proves to be a promising approach by presenting a performance close to the former two approaches without training process, whereas the k-means yields an accuracy about 80%.