Дисертації з теми "FADING ENVIRONMENTS"
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Rohani-Mehdiabadi, Bijan. "Frequency discriminator detection in frequency-selective fading environments." Thesis, Curtin University, 1998. http://hdl.handle.net/20.500.11937/451.
Повний текст джерелаRohani-Mehdiabadi, Bijan. "Frequency discriminator detection in frequency-selective fading environments." Curtin University of Technology, School of Electrical and Computer Engineering, 1998. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=12148.
Повний текст джерелаsuppressed by the use of inverse-limiting in conjunction with frequency discriminator detection. As a result, an effective adaptive detection scheme has been formulated, based on modelling the combination of the GMSK modulator, the mobile channel, the frequency discriminator, and any transmit and receive fitters, as a finite-state machine. The transmitted data is then detected using an MLSE. The BER performance of this proposed adaptive detection scheme has been extensively investigated by computer simulation. This has been carried out assuming various propagation conditions, including the two-ray fading channel model with equal path powers and relative delays of up to four bit periods, the maximum relative delay considered in the GSM system. Also, the effectiveness of the proposed adaptive detection scheme in combatting IS] has been investigated by computer simulation based on the six-ray GSM empirical propagation models for typical urban (TU), hilly terrain (HT) and rural area (RA) environments. The computer simulated results confirm that the voice grade performance required for the GSM system could be achieved by the proposed adaptive detection scheme in all the recommended GSM propagation models considered. Furthermore, the BER performance of the receiver remains unaffected by a carrier frequency offset of up to 2 kHz.
Gifford, Wesley M. (Wesley Michael) 1979. "Diversity with practical channel estimation in arbitrary fading environments." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/16698.
Повний текст джерелаIncludes bibliographical references (p. 79-83).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
This thesis presents a framework for evaluating the bit error probability of Nd-branch diversity combining in the presence of non-ideal channel estimates. The estimator structure is based on the maximum likelihood (ML) estimate and arises naturally as the sample mean of Np pilot symbols. The framework presented requires only the evaluation of a single integral involving the moment generating function of the norm square of the channel gain vector, and is applicable to channels with arbitrary distribution, including correlated fading. Analytical results show that the practical ML channel estimator preserves the diversity order of an Nd-branch diversity system, contrary to conclusions in the literature based upon a model that assumes a fixed correlation between the channel and its estimate. Finally, the asymptotic signal-to-noise ratio (SNR) penalty due to estimation error is investigated. This investigation reveals that the penalty has surprisingly little dependence on the number of diversity branches.
by Wesley M. Gifford.
S.M.
Yan, Ming. "Antenna array receiver design and analysis in fast fading environments /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2001. http://wwwlib.umi.com/cr/ucsd/fullcit?p3022209.
Повний текст джерелаLuong, Dung Viet Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Optimal training sequence design for MIMO-OFDM in spatially correlated fading environments." Awarded by:University of New South Wales. Electrical Engineering & Telecommunications, 2009. http://handle.unsw.edu.au/1959.4/44513.
Повний текст джерелаLaneman, J. Nicholas. "Channel estimation and equalization for spread-response precoding systems in fading environments." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/42673.
Повний текст джерелаPrabhakaran, Preetha. "Performance evaluation of mobile ad hoc networks in realistic mobility and fading environments." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001159.
Повний текст джерелаSvasti-Xuto, Usa. "Performance analyses of frequency-hopped spread-spectrum multiple access systems in fading environments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32771.pdf.
Повний текст джерелаAnnamalai, Annamalai. "Accurate and efficient analysis of wireless digital communication systems in multiuser and multipath fading environments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ37328.pdf.
Повний текст джерелаLiou, Anthony En-Lee. "Characterization of fading and polarization state dispersion on fixed wireless links in suburban macrocell environments." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/14716.
Повний текст джерелаKiessling, Mario [Verfasser]. "Statistical Analysis and Transmit Prefiltering for MIMO Wireless Systems in Correlated Fading Environments / Mario Kiessling." Aachen : Shaker, 2004. http://d-nb.info/1172613060/34.
Повний текст джерелаBejjenki, Praneeth Kumar, Muneeb Ahmed Goraya, and Syed Fovad Moid. "OPTIMIZED FUZZY BASED POWER CONTROL STRATEGY IN COGNITIVE RADIO NETWORKS IN MULTI FADING PROPAGATION ENVIRONMENTS." Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4160.
Повний текст джерелаmobile: 0735032048 (Muneeb Goraya)
Gui, Xiang, and 歸翔. "A technique for performance improvement of DS SS systems operating in fading and jamming environments." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31236923.
Повний текст джерелаGui, Xiang. "A technique for performance improvement of DS SS systems operating in fading and jamming environments /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20294062.
Повний текст джерелаLichtenstein, Joseph. "Low computational complexity bit error rate simulation for personal communications systems in multipath and fading environments." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06102009-063138/.
Повний текст джерелаPhua, Cheng Tatt Valance. "A communication protocol framework for wireless sensor networks in industrial environments." University of Western Australia. School of Computer Science and Software Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0179.
Повний текст джерелаPortelinha, Junior Francisco Martins. "Avaliação do desempenho de redes de rádios cognitivos em ambientes com desvanecimento = Performance evaluation of cognitive radio networks in fading environments." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259708.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
Ibanez, Marc B. (Marc Benedict). "Cellular power control in a fading environment." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/11297.
Повний текст джерелаBanik, Tuhin. "Spatial fading characteristics of VHF broadcast signals in an urban environment." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:8881/R/?func=dbin-jump-full&object_id=61679.
Повний текст джерелаWu, Yating. "Code tracking for direct-sequence spread-spectrum systems under multiuser environment and multipath fading channels /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-ee-b30082602f.pdf.
Повний текст джерела"Submitted to Department of Electronic Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves 105-111)
Hamilton, Benjamin Russell. "Low-Overhead Opportunistic Routing for Wireless Ad Hoc and Sensor Networks in a Fading Environment." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19749.
Повний текст джерелаEleftheriou, Evangelos Carleton University Dissertation Engineering Electrical. "Adaptive filtering in a time-varying environment with applications to equalization of fading HF channels." Ottawa, 1985.
Знайти повний текст джерелаKline, Elizabeth A. "Multi-variant analysis of real-world environmental variables affecting image fading on outdoor synthetic inkjet substrates /." Online version of thesis, 2006. https://ritdml.rit.edu/dspace/handle/1850/2845.
Повний текст джерелаSpyrou, Evangelos. "Performance analysis of wireless LAN signals transmitted over a ricean fading channel in a pulsed-noise preference environment." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FSpyrou.pdf.
Повний текст джерелаThesis Advisor(s): R. Clark Robertson. Includes bibliographical references (p. 67-68). Also available online.
Shih, Wan-Chun. "Performance analysis of variable code rate signals transmitted over frequency-nonselective, slowly fading channels in a pulse-interference environment." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Sep%5FShih.pdf.
Повний текст джерелаKosa, Irfan. "Performance of IEEE 802.11a wireless LAN standard over frequency-selective, slowly fading Nakagami channels in a pulsed jamming environment." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FKosa.pdf.
Повний текст джерелаThesis advisor(s): R. Clark Robertson, Tri Ha. Includes bibliographical references (p. 107-108). Also available online.
Soelaiman, Adi Dharma, and Rina Pudjiastuti. "A Survays On Fading Channel Over West - Java Area for Flight Test Radio Telemetering Purposes." International Foundation for Telemetering, 1988. http://hdl.handle.net/10150/615047.
Повний текст джерелаThis paper discusses one approach to determine a characteristic of West - Java's air and ground segment as a block-box to accomodate radio waves propagation, especially in L-band ranges, by evaluating both the topographical data and radio reception pattern as measured from ground based telemetry receiving-end system. All the measured signals are random and assumed to be stationair and ergodic. In order to characterize the channel for polarization diversity reception, some statistical analysis are applied to the signal strength measured of both - RHCP and LHCP components of 1531 MHz propagated waves as transmitted fr om NC212-200 PK-NZJ-aircraft. Some computer calculated correlograms of measured data are shown herewith, it is focused for a certain radio corridor at radial 265E relative to the ground based receiving antenna. More over some curves of predicted multipath gain factor are also presented to gain more theoretical back ground. When this paper is written, a further field experiments on the matter concerned is beeing conducted.
Law, Eugene. "HOW WELL DOES A BLIND, ADAPTIVE CMA EQUALIZER WORK IN A SIMULATED TELEMETRY MULTIPATH ENVIRONMENT." International Foundation for Telemetering, 2004. http://hdl.handle.net/10150/604926.
Повний текст джерелаThis paper will present the results of experiments to characterize the performance of a blind, adaptive constant modulus algorithm (CMA) equalizer in simulated telemetry multipath environments. The variables included modulation method, bit rate, received signal-to-noise ratio, delay of the indirect path relative to the direct path, amplitude of the indirect path relative to the direct path, and fade rate. The main measured parameter was bit error probability (BEP). The tests showed that the equalizer usually improved the data quality in the presence of multipath.
Osman, Taha Mohammed. "FADI : a fault-tolerant environment for distributed processing systems." Thesis, Nottingham Trent University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388867.
Повний текст джерелаChow, Jocelyn. "Performance analysis of a QAM multitone-on-FM system at and above the FM threshold in a non-frequency-selective slowly fading environment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/NQ54404.pdf.
Повний текст джерелаHaghdad, Mehdi, and Kamilo Feher. "SMART ANTENNA (DIVERSITY) AND NON-FEEDBACK IF EQUALIZATION TECHNIQUES FOR LEO SATELLITE COMMUNICATIONS IN A COMPLEX INTERFERENCE ENVIRONMENT." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605382.
Повний текст джерелаAn improved performance smart diversity was invented to improve the signal performance in a combined selective fading, Additive White Gaussian Noise (AWGN), Co-channel interference (CCI) and Doppler shift environment such as the LEO satellite channel. This system is also applicable to aeronautical and telemetry channels. Smart diversity is defined here as a mechanism that selects at each moment the best branch in a n-branch diversity system based on the error quality with no default branch and no prioritization. The predominant novelty of this discovery is the introduction of multi level analog based Pseudo Error Detectors (PSED) in every branch. One of the advantages of PSED is that it is a non redundant error detection system, with no requirement for overhead and no need for additional valuable spectrum. This research was motivated by problems in LEO satellite systems due to low orbit and high relative speed with respect to the ground stations. The system is independent of the modulation techniques and is applicable to both coherent and non-coherent detections. The results from simulations using dynamic simulation techniques and hardware measurements over dynamic channels show significant improvement of both the Bit Error Rate (BER) and the Block Error Rate (BLER).
Araújo, Filho Mário Silva de. "AVALIAÇÃO DOS NÍVEIS DE FADIGA EM TRABALHADORES DE ENFERMAGEM DE UM HOSPITAL ESCOLA." Pontifícia Universidade Católica de Goiás, 2018. http://tede2.pucgoias.edu.br:8080/handle/tede/4074.
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The objective of this study was to evaluate the fatigue levels of nursing professionals at a Hospital Escola de Goiânia, whose specific objectives were to outline the sociodemographic profile, evaluate the fatigue levels associated with the work environment, and compare fatigue levels with variables sociodemographic. Methods; An analytical cross-sectional study with a quantitative approach, with 25 nurses and 94 technicians in nursing. Discussion; it was identified that 97.5% of the interviewees are female, most of them between 20 and 35 years old, who have a double working day, and between 1 and 5 years of nursing service, of which 53.1 % presented fatigue. Conclusion; the study suggests the occurrence of fatigue is associated with the stressful situations experienced by the nursing professional in their work practice, as well as the exposure to physical and biological risks, in addition to the long and painful working days.
O estudo teve como objetivo geral avaliar os níveis de fadiga dos profissionais de enfermagem em um Hospital Escola de Goiânia, teve como objetivos específicos traçar o perfil sociodemográfico, avaliar os níveis de fadiga associados ao ambiente de trabalho e comparar os níveis de fadiga com as variáveis sociodemográficas. Métodos; estudo transversal analítico com abordagem quantitativa, tendo como participantes 25 Enfermeiros e 94 Técnicos em enfermagem A coleta de dados foi realizada entre os meses de junho a agosto de 2017 e ocorreu durante todos os turnos, mediante liberação pela chefia de enfermagem do setor e assinatura do Termo de Consentimento Livre e Esclarecido. Discussão; identificou-se que 97,5% dos entrevistados são do sexo feminino, em sua maioria com faixa etária entre 20 e 35 anos, que possuem dupla jornada de trabalho, e entre 1 a 5 anos de serviço na enfermagem, sendo que 53,1% apresentaram quadro de fadiga. Conclusão; o estudo sugere a ocorrência de fadiga está associada as situações estressantes vivenciadas pelo profissional de enfermagem em sua prática laboral, bem como a exposição a riscos físicos e biológicos, somados as longas e penosas jornadas de trabalho.
Silva, Marta Sofia Mendonça da. "Ambiente físico hospitalar: a influência no burnout, stress, fadiga e satisfação no trabalho dos profissionais de saúde." Master's thesis, Universidade de Évora, 2018. http://hdl.handle.net/10174/23264.
Повний текст джерелаMoreto, Jéferson Aparecido. "Estudo da corrosão e corrosão-fadiga em ligas de Al e Al - Li de alta resistência para aplicação aeronáutica." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-22102012-112635/.
Повний текст джерелаThe aircraft industry is constantly looking for improved materials which offer benefits in terms of performance, weight and cost savings. Corrosion and fatigue of aluminium alloys are major issues in the service life assessment of aircraft structures and in the management of aging air fleets. The aim of this study was to evaluate the corrosion and corrosion fatigue processes of 2198-T851 and 7081-T73511 aluminium alloys, which are promising substitutes for the base line 2524-T3 and 7050-T7451 aluminium alloys normally used in aircraft fabrication. Open circuit potential monitoring (OCP), potentiodynamic polarization, potentiodynamic polarization in rotating cylindrical electrode, eletrochemical impedance spectroscopy (EIS), Scanning vibrating electrode technique (SVET) and Scanning Kelvin Probe (SKP) techniques have been used to clarify and quantify the corrosion mechanisms of these Al alloys. Fatigue and corrosion fatigue tests were carried out an applied stress ratio (R) of 0.1, 15 Hz frequency for air and 0.1 Hz frequency for salt spray using a sinusoidal wave form in all cases. The specimens, before and after corrosion and corrosion-fatigue testing were analyzed using scanning electron microscope (SEM). The localised features of all the four alloys are essentially related to the existence of intermetallics that, due to their different nature, may be cathodic or anodic sites in relation to the Al matrix. SEM and EDS analysis allowed to identify the intermetallics that are more active in determining the corrosion behavior of the specimens. The fatigue corrosion results show a slightly reduction in the fatigue life limit by chloride environment for the 2XXX and 7XXX aluminium alloys in each aged condition might be partially attributed to the formation of corrosion pits. Considering the crack propagation stage, the saline environment increased the fatigue crack growth rate for the same range of stress intensity factor.
Barbosa, José Fernando Cárdenas. "Fatigue crack propagation in AA 7050-T7451 alloy considering environment, stress ratio, rolling direction and waveform effects." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18158/tde-27062017-111140/.
Повний текст джерелаOs principais fatores modificadores extrínsecos e intrínsecos da taxa de propagação de trincas na liga AA7050-T7451 foram avaliados para fornecer subsídios para projetistas de estruturas aeronáuticas, com base na filosofía de tolerância ao dano. A metodologia experimental consistiu em ensaiar corpos de prova do tipo compact tension (CT) da liga nas direções de laminação TL e LT, para verificar seu comportamento sob diferentes razões de tensões, forma de onda e condição ambiente. Os valores de razão de tensão estudados foram 0,1 e 0,5, as formas de onda foram senoidal e trapezoidal ou de Dwell, em condições normais de laboratório, ao ar, e névoa salina 3,5% NaCl, em massa, para simular um ambiente marinho. No caso dos ensaios Dwell, os resultados foram conferidos pelo método de queda de potencial eléctrico (QPE), além do método de flexibilidade elástica. Usando os coeficientes de Walker calculados a partir dos resultados obtidos, pôde-se projetar com precisão o comportamento da propagação de trinca na região de Paris e prever a vida em fadiga usando os diagramas da/dN e S-N para diferentes valores da razão de tensões. O ambiente corrosivo aumenta tanto a taxa de propagação de trinca, quanto o valor de ΔKth por causa da formação de óxidos na trajetória da trinca, que geram um efeito de fechamento sobre a mesma. Quanto à forma de onda, verificou-se que o carregamento Dwell diminui a taxa de propagação de trinca, diminuindo a inclinação das curvas log (da/dN) versus log (ΔK) na região de Paris, ao invés de deslocá-la paralelamente como ocorre com ligas de titânio. A mudança da direção de laminação de LT para TL aumenta a taxa de propagação de trinca por fadiga (PTF) tanto na região de threshold, quanto na região de Paris, onde a mudança de taxa é pequena.
Kirsch, Alessandra. "Politique agricole commune, aides directes de l'agriculture et environnement : analyse en France, en Allemagne et au Royaume-Uni." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCG001/document.
Повний текст джерелаDoes the CAP direct payment distribution benefit to the most environmentally friendly farms? Following an environmental assessment state of the art, a set of environmental indicators has been created to rank farms on their potential environmental impacts using FADN datas. Then, these classes have been connected with the amounts of direct payments received. Results are processed on three types of farm (specialized in cereals and oilseeds, meat cows and milk cows). Associated with a comprehensive study of the reforms of the CAP since 1992, this empirical study allows to stand back on the consequences of the political decisions. It seems that if the 2nd pillar direct payments are directed in favour of the more environmental friendly farms, their weight remains too low compared with the aids of the 1st pillar, which are higher in the less virtuous farms. This is largely connected to the weight of the DPU in the direct payments, and to the French choice to base their calculation with regard to the history of the farm. That is why the simulations of the redistribution of the subsidies of the 1st pillar on horizon 2019 show that the rebalancing of these payments between the farms by a national harmonization will contribute to level the gap of 1st pillar direct payments by hectare between french farms. The comparison with the United Kingdom and Germany shows the effects of the subsidiarity, in particular during the decoupling: the harmonization of the decoupled payments allows the most environmental friendly farms to get higher direct payments per hectare
Ghandour-Haidar, Soukayna. "Estimation de canal à évanouissements plats dans les transmissions sans fils à relais multibonds." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT102.
Повний текст джерелаThis thesis deals with the estimation of the multihop Amplify-and-Forward relay communications. The various objects (transmitter, relays, receivers) can be fixed or mobile. Each link is modeled by a flat fading Rayleigh channel, with a Doppler spectrum resulting from two-dimensional (2D, leading to the U-shape Dopller spectrum) or three-dimensional (3D, leading to a flat Doppler spectrum) scattering environments. The cascade of channel hops is approximated by a first-order autoregressive (AR(1)) model and is tracked by a standard estimation algorithm, the Kalman Filter (KF). The common method used in the literature to tune the parameter of the AR(1) model is based on a Correlation Matching (CM) criterion. However, for slow fading variations, another criterion based on the off-line Minimization of the Asymptotic Variance (MAV) of the KF is shown to be more appropriate. For both the CM and MAV criteria, this thesis gives analytic justification by providing approximated closed-form expressions of the estimation variance in output of the Kalman filter, and of the optimal AR(1) parameter. The analytical results are calculated for given Doppler frequencies and Signal-to-Noise Ratio for both scattering environments, whatever the number and type of transmission hops (Fixed-to-Mobile or Mobile-to-Mobile). The simulation results show a considerable gain in terms of the Mean Square Error (MSE) of the well tuned Kalman-based channel estimator, especially for the most common scenario of slow-fading channel
CHANDRA, MUDITA. "PERFORMANCE ANALYSIS OF TURBO CODES IN FADING ENVIRONMENTS." Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14972.
Повний текст джерелаHe, Yue-Jing, and 何岳璟. "Modeling of Radio Multipath Fading Channels in Picocellular and Microcellular Environments." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/44860459932304519197.
Повний текст джерела國立交通大學
電信工程系
88
In this thesis, we present the hybrid model to research the characteristic of multipath fading in picocell (indoor) and microcell (urban). It is composed of 2-dimension adaptive site-specific model and scattering model. Adaptive site-specific model comprises the reflection, scattering and transmission effect of boundary in the transmission environment. Scattering model can be used to describe the scattering field as a result of random distribution of scattering object and the rough surface boundary. It is found that this treatment can decrease the number ray-tree levels of the site-specific model and saves a lot of computational time. In addition to accurately predicting mean field strength, the hybrid model can effectively quantify the contribution of scattering field (relative to mean value) with the relative scattering factor r. A large amount of experiment data at many different sites (2.44GHz for picocell, 900MHz for microcell) shows that a Nakagami distribution describes the fading distribution well in picocellular and microcellular environment. After measuring live on the spot, we find that in the picocell: (1) r = 0.65~0.72 if the receiving or transmitting antenna is in a heavy cluttering environment; (2) r = 0.26~0.35 if the receiving or transmitting antenna is in a light cluttering environment. While in microcell model, r = 0.1~0.2 because both transmitting and receiving are in light cluttering environment, it can model the statistical characteristic of multipath fading in different environment effectively.
Li, Jing Yang, and 李景洋. "Diversity transmission techniques for framed ALOHA communication system in fading environments." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/30994630531238204979.
Повний текст джерелаChen, Chia-Yi, and 陳家溢. "On the Behavior of Noncoherent Delay-Locked Loops in Mutipath Fading Environments." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/81330537851198065714.
Повний текст джерела國立交通大學
電信研究所
85
Noncoherent {\it delay-locked loops} (DLL) are often employed to track the code phase of the pseudo noise (PN) sequence used in a direct-sequence spread spectrum (DS/SS) system. In a wireless radio communication environment, the performence of a noncoherent DLL is affected not only by additive white Gaussian noise (AWGN) but also by multipath fading. This thesis investigates the behavior of noncoherent DDLs in a class of simple time-varying fading channels. Numerical method is used to solve the transition probability density function (pdf) of the tracking error and to study the transient behavior of a noncoherent loop. Detailed discussion on the numerical problems encountered in the course of deriving the desired solution is provided. {\it Mean time to lose lock} (MTLL) and {\it tracking error} are the two major performance measures of concern to us. Because the code phase error can be modeled as a renewal process, {\it Renewal Process Approach} (RPA) can be applied to analyze the performance of tracking loops. In a time-varying channel, however, we find that stationary analysis using RPA does not lead to correct estimates of the MTLL and the tracking error. We also analyze the performance of a class of code tracking loops called improved DLL that has a wider S-curve, larger pull-in and lock-in ranges.
Hiep, Le Hoang, and 黎黃協(Le Hoang Hiep). "Developing An Algorithm of Signal Scheduling Management for Heterogeneous Networks over Fading Environments." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/3au66b.
Повний текст джерела大葉大學
電機工程學系
103
In this dissertation, an efficient algorithm target tracking is studied using mobile sensor network in a heterogeneous network (HetNet). The purpose of the research focuses on a method which attempt to approach an optimal sensor scheduling to track a moving target such that it minimizes the measurement error, reduces the sensor usage cost and satisfies the constraints under consideration. In this study, a wireless Heterogeneous Network (HetNet) is considered as a fading propagation environment. To model for this kind of channel, authors applied m-Nakagami distribution as an efficient distribution for a fading propagation. Accordingly, the Kalman filter technique to predict position of target in posteriori state is applied. A new algorithm was proposed to recognize a most likely trajectory of this mobile user and to minimize resource consumption by scheduling an efficient moving for the mobile sensor network. A simulation for the case of three mobile sensors track a target moving, e.g. a mobile user, was considered. The position and velocity of target were assumed given in the initial state, then these sensors transmitted the measured information of target in recent state to a base station every time length. Based on received data of this priori state measurement, a management system embedded in base station would predict the posteriori state of target. Next, the base station transmitted commands to control these sensors move properly such that tracking system does not miss the target. In this simulation, total distance of itinerary of sensors represented resource consumption. Numerical results presented that the purposed algorithm gets a better performance than regular one by spending less executing time and estimated trajectory of target was almost similar to regular one. Keywords: mobile target tracking, wireless sensor network, Kalman filter, heterogeneous network, m-Nakagami.
Svasti-Xuto, Usa. "Performance analyses of frequency-hopped spread-spectrum multiple access systems in fading environments." Thesis, 1996. http://hdl.handle.net/1828/8223.
Повний текст джерелаGraduate
CHIU, KAI-MING, and 邱開明. "Investigating in the System Performance of UWB Systems Operating over Frequency Selective Fading Environments." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/40947489659973830053.
Повний текст джерела大葉大學
電信工程學系碩士在職專班
95
The Federal Communications Commission (FCC) has allocated 7,500MHz spectrum for unlicensed use of ultra-wideband (UWB) devices in the 3.1 to 10.6 GHz frequency band. The UWB techniques belong to the protocol of 802.15.3a, that is, the UWB will be the most one technical applied in the wireless communication systems. Especially, it is one of the most important fechnique for application in military service, since the base station is not needed for the UWB system. The UWB communication methods will be the most adaptive application for small enterprises since it owns the unlicensed spectrum. Thus, the UWB wireless communication technique will be adopted in this paper for studing in order to research and dervelop some added applications in private area. Combining the high dense multiple access of AIRMA (analog impulse radio multiple access) with DIRMA (Digital impulse radio multiple access) will be held in this study. Some of the theories of UWB system will be derived by using the theory means. Hence, the advantages for the UWB technique will be cleared, and some of the results from this investigation will be provided to apply in the real world applications. Besides, the operation environments with frequency sclectve fading channel are also combined with the analysis of the system performance.
Shih-Tan, Wang, and 王世坦. "Outage Performance of Maximal Ratio Combining Technique Working over the Environments of Fading Channel." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/25632199874091997541.
Повний текст джерела大葉大學
電信工程學系碩士在職專班
93
The Nakagami fading distribution is assumed in this thesis for investigating the outage performance of digital communication with MRC (maximal ratio combining) diversity technique. Besides, the phenomena of CCI (co-channel interference), frequency selective channel, and the random communication branch are also considered in here. In this thesis some new formulae of outage performance are proposed. The numerical results obviously show that not only the characteristics parameters of the channel model, but the number of branch also affect the performance of wireless radio systems over CCI environments.
Annamalai, Annamalai Jr. "Accurate and efficient analysis of wireless digital communication systems in multiuser and multipath fading environments." Thesis, 1999. https://dspace.library.uvic.ca//handle/1828/8687.
Повний текст джерелаGraduate
Wen, Hsieh Tai, and 謝岱彣. "On the Impact of CFO for an MC-DS-CDMA System in Weibull Fading Environments." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/09335079770363173618.
Повний текст джерела大葉大學
電機工程學系
98
On the basis of CFO (carrier frequency offset) point of view, the system performance results from the analysis by adopting the channel scenarios characterized as Weibull fading for an MC-DS-CDMA (multi-carrier direct-sequence coded-division multiple-access) system are proposed in this article. Moreover, an approximate simple expression with the criterion of BER (bit error rate) versus SNR (signal-to-noise ratio) method is derived for an MC-DS-CDMA system combining with MRC (maximal ratio combining) diversity based on the MGF (moment generating function) formula of Weibull statistics, and it associates with an alternative expression of Gaussian Q-function. In addition, the other point of view on the BER performance evaluation of an MC-DS-CDMA system is not only the assumption of both single-user and multi-user cases applied, but the phenomena of PBI (partial band interference) is also included. Furthermore, with several of the system parameters, such as CFO values, ε, Weibull fading parameter, β, user number, K, spreading chip number, N, branch number, L, and the PBI values, JSR, etc., are compared with each other in the numerical results in order to validate the accuracy in the derived formulas. To the best of author’s knowledge, it is a brain fresh idea proposed in this paper to evaluate the system performance for an MC-DS-CDMA system on the point of the CFO view over Weibull fading.
Lin, Yung-Jeng, and 林永正. "Impact of Multipath Fading on the Quality of Signal Transmission in High Speed Railway Environments." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/78150295175371650660.
Повний текст джерелаHUNG, CHUN-TIEN, and 洪春田. "Study on the Performance of NC-MFSK with Selective Combining Diversity over Weibull Fading Environments." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/21605773189259607114.
Повний текст джерела大葉大學
電信工程學系碩士在職專班
93
The methods applied to improve the receiver of wireless communication system with digital modulation combines and diversity combining manners are investigated in this thesis. The channel fading phenomena exist in the modulation schemes are also considered in this study. There are some of the famous and most assumption channel model introduced in my study. The main reason for adopting the Weibull distribution in my study is it has the shape parameter can be applied to characterize the channel fading. On the other hands, the performance of average LCR (level crossing rates) and AFD (average fading durations) for the simplest combining diversity, SC (selection combining), are also evaluated in here. In fact, in this paper some of the formulas of BER (bit error rate) performance are proposed for the SC diversity with noncoherent MFSK (M-ary frequency shift keying) and DQPSK (difference quaternary phase shift keying) over Weibull fading environments.
Tu, Wen Sheng, and 杜文生. "The Combining Diversity Techniques Frequently Applied in Wireless Radio System over Frequency Selective Fading Environments." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/86289807712821102908.
Повний текст джерела大葉大學
電信工程學系碩士在職專班
95
The channel capacity of dual-branch MRC (maximal ratio combining) diversity system over correlated waveform intensity, which is characterized as correlated-Nakagami-m fading (the power is modeled as the correlated-Gamma statistics), is evaluated in this paper. The formulas of channel capacity performance are provided with a pdf (probability density function)-based approach. The pdf of sum of Gamma variates based on the representation of the Moschopoulos single gamma series is adopted in the report. The corresponding expressions for Rayleigh fading are obtained as a special case of Nakagami-m fading. Finally, the numerical examples are presented for illustrating the purpose of the validation of the channel capacity equations derived in this paper.