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This paper investigates the impacts that open-trench drains make on the accuracy of radio propagation prediction in an urban city environment. Compared with conventional prediction styles that assume the ground to be flat, in this paper, we have considered for the first time the real scenario in many Asian cities to make open-trench drains inclusive in radio propagation modeling. The aims of this paper are twofold. First, to scrutinize one narrow L-shaped structure, modeled after an open-trench drain, by means of comparing ray-tracing simulation results with the actual field measurement results at 2.4 and 5.8 GHz. Second, to compare one city model built without and with the inclusion of open-trench drains for running ray-tracing simulation in yielding radio propagation prediction results. The findings from this paper are especially beneficial to the improvement of mobile communications in extraordinary environments such as open-trench drains, caves, coal mines, underground passageway, and others. Besides, they provide a unique insight into how the presence of the open-trench drains may affect radio wave propagation in an urban city environment.

Accurate indoor radio wave propagation prediction requires a model of the environment which also includes fixtures such as furniture. By laser scanning we can obtain this detailed structural data in the form of a point cloud. Since conventional field prediction tools are not applicable to the point cloud data format, we predict the electromagnetic scattering by using a single-lobe directive scattering model which can be used directly with the point cloud. The focus in this letter is to study how the density of the point cloud affects the prediction accuracy. It is shown that a point cloud density of only $2 \cdot {10^{ - 4}}$ points per square wavelength is enough at 60 GHz in order to achieve good prediction accuracy between measured and predicted delay and angular spreads.

© 2017 IEEE. This paper presents a physical-statistical radio channel power delay profiles model for room-to-room communication systems combining the room electromagnetic theory for modeling deterministic channel components with a geometry-based stochastic channel model with time-variant statistics for modeling stochastic components. The deterministic channel component, i.e., mean power delay spectrum, is comprised of specularly reflected paths plus diffuse components due to scattering and diffraction. The specular components are modeled with a set Dirac function, whereas the diffuse components modeling approach is a room electromagnetic theory-based model. Dynamic indoor communication channels are characterized by a non-stationary time- and delay-fading process due to changes in the environment. We analyze and model the time-delay variability of channels using K -factor for small-scale variations and the t -location scale distribution parameters for large-scale variations. It turns out that these parameters cannot be assumed to be constant in time and delay. After modeling of time-delay variations of the first order statistics, we generate channel realizations with appropriate second order statistics. As the result, the presented model enables to describe the evolution of the power delay profile in the time domain. ispartof: IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS vol:16 issue:10 pages:6493-6502 status: published

In radio system deployment, the main focus is on assuring sufficient coverage, which can be estimated with path loss models for specific scenarios. When more detailed performance metrics such as peak throughput are studied, the environment has to be modeled accurately in order to estimate multipath behavior. By means of laser scanning we can acquire very accurate data of indoor environments, but the format of the scanning data, a point cloud, cannot be used directly in available deterministic propagation prediction tools. Therefore, we propose to use a single-lobe directive model, which calculates the electromagnetic field scattering from a small surface and is applicable to the point cloud, and describe the overall field as fully diffuse backscattering from the point cloud. The focus of this paper is to validate the point cloud-based full diffuse propagation prediction method at 60 GHz. The performance is evaluated by comparing characteristics of measured and predicted power delay profiles in a small office room and an ultrasonic inspection room in a hospital. Also directional characteristics are investigated. It is shown that by considering single-bounce scattering only, the mean delay can be estimated with an average error of 2.6% and the RMS delay spread with an average error of 8.2%. The errors when calculating the azimuth and elevation spreads are 2.6° and 0.6°, respectively. Furthermore, the results demonstrate the applicability of a single parameter set to characterize the propagation channel in all transmit and receive antenna locations in the tested scenarios.

An approach that predicts the propagation, models the terrestrial receivers and optimizes the performance of single frequency networks (SFN) for digital video broadcasting in terms of the final coverage achieved over any geographical region, enhancing the most populated areas, is proposed in this paper. The effective coverage improvement and thus, the self-interference reduction in the SFN is accomplished by optimizing the internal static delays, sector antenna gain, and both azimuth and elevation orientation for every transmitter within the network using the heuristic simulated annealing (SA) algorithm. Decimation and elevation filtering techniques have been considered and applied to reduce the computational cost of the SA-based approach, including results that demonstrate the improvements achieved. Further representative results for two SFN in different scenarios considering the effect on the final coverage of optimizing any of the transmitter parameters previously outlined or a combination of some of them are reported and discussed in order to show both, the performance of the method and how increasing gradually the complexity of the model for the transmitters leads to more realistic and accurate results. This work was supported by the Spanish Ministry of Science and Innovation under Projects TEC2008-02730 and TEC2012-33321. The work of M. Lanza and Á. L. Gutiérrez was supported by a Pre-Doctoral Grant from the University of Cantabria.

Particle filters are well-known as powerful tools for accomplishing state and parameter estimation and their propagation prediction in nonlinear dynamical systems. Their ability to include system model parameters as part of the system state vector is among one of the key factors for their use in prognostics. Estimation of system parameters along with the states produces an updated model that can be used for long-term prediction. This paper presents a novel method for uncertainty management in long-term prediction using particle filters. In our proposed approach, the observation prediction concept is applied in order to extend the system observation profiles (as time series) for future. Next, particles are propagated to future time instants according to the resampling algorithm instead of considering constant weights for their propagation in the prediction step. The uncertainty in the long-term prediction of system states and parameters are managed by utilizing fixed-lag dynamic linear models. The observation prediction is achieved along with an outer adjustment loop to change the observation injection window adaptively based on the Mahalanobis distance criteria. The proposed approach is applied to predict the health of a gas turbine system that is affected by the degradation in the system health parameters. 2014 American Automatic Control Council. Qatar National Research Fund Scopus

Smart antennas have been recently applied to improve the capacity and the performance of second generation wireless mobile communication systems. In general, smart antennas reduce the effects of multipath fading and improve the signal-to-noise-plus-interference ratio (SNIR). Additional advantages such as channel capacity increase in urban areas, coverage extension in urban areas and spectrum efficiency in general can be obtained with the aid of smart antennas at the base station. Drawbacks are the cost, and both hardware and software complexity. Smart antennas promise a clear advantage in multi-service traffic scenario in comparison with non-adaptive antenna techniques. It is generally accepted that the adaptive antennas technique will be a key enable for the success of the European third generation mobile communication system known as Universal Mobile Telecommunication System (UMTS). The first part of this thesis presents two types of smart antenna systems: switched beam antennas and adaptive arrays. It introduces statistical models for them and investigates the performance measures of cellular radio systems with and without smart antennas deployed at base stations. Employing Monte-Carlo methodology, a tool has been developed to analyze the interference between two different systems that share the same geographical area and have neighboring frequency channels. The statistical smart antennas model has been used to verify the mitigation of the interference compared with others antennas used at the base station. These simulations have been done for TDMA, FDMA and CDMA systems. Wireless communication operating at different frequencies on the non-ionizing radiation (NIR) region of the electromagnetic spectrum has greatly increased in the last few decades, with important benefits for the population. These include mobile communication, such as cellular telephone systems. However, the radiated electromagnetic field levels increased substantially in areas where people may stay during long periods each day. This may result in long-term exposure to the population. International guidelines and standards were developed aiming at protecting the population, and limiting the maximum radiation produced. The methods used by regulation authorities to evaluate the field levels at places of sensitive use yield very conservative results. They need thus to be refined prior to the introduction of adaptive antennas. In the second part of the thesis, a 3D ray tracing tool is developed to predict the propagation for real scenarios using UMTS systems. This tool takes into account 3D radiation diagrams and multipath propagation. It was used in real scenarios to compare the real field levels with the levels obtained by the approximate methods defined by the regulation standards. Finally, this tool was used to predict the field levels in a scenario containing smart antennas. Scenario not foreseen in the method described in the standards.

Presented here is software for indoor signal strength prediction. Software parameters and calculation process using beam tracing for fast and accurate prediction are explained. Also given is the measurement equipment and setup used to verify the calculation process in the 2.4 GHz ISM band. Received signal strength was measured inside an office building and calculations on the same environment were done using the prediction software. The measurement results are compared to the calculations over two routes and on several key points.

ÖZET şehir İçinde yayılım simülasyonu için işin İzleme algoritması geliştirilmesi ve uygulanması Gökhan Moral Elektrik ve Elektronik Mühendisliği Bölümü Yüksek Lisans Tez Yöneticisi: Prof. Dr. Hayrettin Köymen Ağustos 2002 Kullanımı gün geçtikçe artan radyo tabanlı iletişim yöntemleri, fiziksel olarak kısıtlı bir kaynak olan frekans spektrumunun daha verimli kullanılması gereğini doğurmuştur. Bunu sağlamak için son zamanlarda iç ve dış mekanlardaki alan şiddeti ve gecikme dağılımı gibi parametreleri hesaplamak için çok popüler olan ışın izleme yöntemi geliştirilmiştir. Bu yöntem, içinde bulunulan ve kanal olarak kullanılan ortamdaki yolların, caddelerin ve cisimlerin etkilerini ayrı ayrı in celediğinden ve maddelerin elektromanyetik özelliklerine bağlı olarak yansıma ve saçınımları hesapladığından dolayı diğer empirik yöntemlere göre daha doğru ve mantıksal sonuçlar vermektedir. Mobil ağ planlamasında kullanılabilecek değerli bir bilgi olan dürtü yanıtı bu yöntem ile bulunabilmektedir. Bu tezde ışın izleme algoritması geliştirilmiş, bir takım örnek şehir verisi kullanılarak test edilmiş, sonuçlar diğer empirik modellerin ve benzer ışın izleme yöntemlerinin sonuçları ile karşılaştırılmıştır. Anahtar kelimeler: yayılım tahmini, ışın izleme, radyo tabanlı iletişim, şehir içinde yayılım modeli. iv ABSTRACT DEVELOPMENT AND APPLICATION OF A RAY TRACING ALGORITHM FOR PROPAGATION SIMULATION IN URBAN AREAS Gökhan Moral M.S. in Electrical and Electronics Engineering Supervisor: Prof. Dr. Hayrettin Köymen August 2002 With the increasing demand on radio communication systems, the natural spec trum resource should be used more efficiently. In this thesis, a ray-tracing method is implemented in order to calculate signal strength values for outdoor wireless communication in an urban environment. The ray tracing method considers the electromagnetic properties of the communication environment and it gives more accurate results and more information about the channel in comparison to available empirical models. In this thesis, a 2D ray-tracing algorithm has been developed with some assumptions to optimize the speed while conserving the accuracy. The computer program developed is then used to simulate radio propagation in several example environments and the results obtained from the simulations are compared with the results obtained by using another ray-tracing computer software package. Keywords: propagation prediction, ray-tracing, wireless radio communications, urban propagation models in 81