Dissertations / Theses on the topic 'CDMA'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'CDMA.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Deus, Junior Getulio Antero de. "Sistemas FFH-CDMA codificados." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260269.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-02T01:11:32Z (GMT). No. of bitstreams: 1 DeusJunior_GetulioAnterode_D.pdf: 9215941 bytes, checksum: 93364e4dd602d44e4f2d6d1758043dfd (MD5) Previous issue date: 2002
Resumo: Neste trabalho é desenvolvido um estudo sobre um sistema FFH-CDMA cujo receptor de máxima verossimilhança (MV) não-quantizado necessita de uma não-linearidade de difícil implementação. Para um sistema FFH-CDMA não-codificado propomos a utilização de um único perceptron para a implementação da não-linearidade. Esta proposta demonstrou apresentar degradação desprezível quando comparada ao receptor de MV. O cálculo da probabilidade de erro par-a-par tanto para receptores quantizados quanto para não-quantizados, foi também realizado. Um sistema que utiliza um receptor de :MVnão-quantizado demonstrou possuir ganho considerável em termos do número de usuários simultâneos quando comparado a um sistema quantizado. Motivados por este fato, realizamos cálculos para a capacidade de canal por dimensão e para a taxa de corte de canal do sistema FFH-CDMA considerado. Os resultados mostraram ganhos significativos do sistema tanto em termos de número de usuários simultâneos, como também em termos de relação sinal-ruído (para a probabilidade e o número de usuários fixados). A partir de uma aproximação para a probabilidade de erro par-a-par, um critério de projeto dos codificadores é proposto. Alguns codificadores convolucionais que se adequam ao critério proposto podem ser encontrados da literatura. Resultados de desempenho obtidos através de simulação e de limitantes superiores para códigos convolucionais terminados encontrados na literatura, mostraram a eficiência do critério de projeto sugerido para os codificadores. A partir das expressões para a taxa de corte de canal pode-se obter valores otimizados para taxas de codificação. Nem todos estes valores se encontram na literatura. Sendo assim, um algoritmo de procura de codificadores foi desenvolvido de acordo com o critério de projeto sugerido. Vários codificadores foram encontrados que podem eventualmente ser utilizados em outras aplicações. Alguns codificadores obtidos comprovam que um sistema FFH-CDMA codificado, com uma treliça de 1024 estados, pode trabalhar bem próximo da taxa de corte de canal
Abstract: This work presents a study of FFH-CDMA systems whose maximum likelihood (ML) receiver uses a nonlinearity of difficult of implementation. For an uncoded FFH-CDMA system, we propose the use of an unique perceptron to approximate the optimum nonlinearity. The proposed perceptron has performance almost identical to ML detection. An unquantized FFH-CDMA system can support a considerable greater number of simultaneous active users than a quantized FFH-CDMA system. Motivated by this fact, we evaluated the normalized sum capacity and the channel cutoff rate of the considered system. The results have showed expressive gains of an unquantized FFH-CDMA system in terms of number of active users as well as in terms of signal-to-noise ratio. Starting from an approximation of the pairwise error probability, a design criterion is proposed. Performance results obtained through computer simulation and upper bounds for convolutional codes found in the literature, showed the effectiveness of the proposed design criterion. A search algorithm for finding codes based on this criterion was implemented. Some of the coders obtained give evidence that a coded FFH-CDMA system, with a trellis of 1024 states, can work near channel cutoff rate
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica
Venkatasubramanian, Ramasamy. "Beamforming for MC-CDMA." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31287.
Full textMaster of Science
LE, BOT MARIE. "Antennes adaptatives en CDMA." Paris, CNAM, 2001. http://www.theses.fr/2001CNAM0384.
Full textSHEN, HANHONG. "SEMIBLIND MULTIUSER DETECTION FOR MC-CDMA." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1127324165.
Full textSHARMA, ANSHUL. "Performance Analysis of MC-CDMA and CI/MC-CDMA Using Interference Cancellation Techniques." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1218826853.
Full textJakubek, David Andrew. "Coherent/noncoherent detection of coherent optical heterodyne DPSK-CDMA and MFSK-CDMA signals." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28033.
Full textHaiou, Zheng, and Zhang Naitong. "ANALYSIS OF HYBRID FDMA/CDMA SYSTEMS IN RICIAN FADING." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/606808.
Full textIn this paper, a hybrid frequency division multiple access/code division multiple access (FDMA/CDMA) system in a Rician fading channel is described and analysis. The performance of the hybrid system is compared with a wideband CDMA system, which occupies the same total bandwidth. The results show that for DPSK modulation with a RIKE receiver, a hybrid system can have a greater capacity with a strong direct path component or a high signal to noise ratio (SNR). Otherwise, a wideband system remains optimal.
Cheung, Tze Chiu. "2GHz W-CDMA Radio Transceiver." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36411.
Full textMaster of Science
Duran, Omer Agah. "Multiuser Receivers For Cdma Downlink." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609953/index.pdf.
Full textWan, William Ming. "Digital CDMA multi-carrier demodulator." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/MQ28260.pdf.
Full textSorokine, Vladislav. "Gallager codes for CDMA applications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ35329.pdf.
Full textTanner, Rudolf. "Nonlinear receivers for DS-CDMA." Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/1377.
Full textHuang, Hu, and 黃鵠. "Multicarrier DS/SFH-CDMA systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31222705.
Full textIltis, Ronald A. "Localization Using CDMA-MIMO Radar." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/605975.
Full textA MIMO radar system for target localization is presented which uses direct-sequence CDMA (DS-CDMA) waveforms. The received DS-CDMA signal at each antenna is expressed directly in terms of the target positions. The waveforms employed are Gold sequences, and hence are not exactly orthogonal. A generalized successive interference cancellation (GSIC) approach is used to resolve multiple scatterers and reduce clutter. Simulation results are presented which suggest the capability to detect weak scatterers in the presence of clutter using the cancellation method.
Filho, Rivail Vilas Boas dos Santos. "Análise de sistemas CDMA ópticos." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-06102006-104349/.
Full textThe evolution of optical networks verified in the last few years has been characterized by the search for better bandwidth utilization efficiency. The successful implementation of practical code division for multiple access techniques (CDMA) in mobile communications systems has stimulated new investigations on this topic, particularly in the optical domain (optical CDMA). This is justified due to some remarkable attributes of this technology, such flexibility in code design, capacity on demand, safety, and high scalability. In this context, this dissertation presents, initially, a comprehensive review of several code configurations for OCDMA proposed in the literature, with emphasis particularly on the correlation and users availability properties. Next, it describes the modeling of an optical system consisting of the following three subsystems: generation, transmission, and signal detection. The penalties imposed to the optical codes by the propagating medium, as well as by the devices employed in the system, are accounted for and their influence on the performance of some coding configurations is investigated. The knowledge of how and when these penalties will affect the system is crucial in optical signal processing based on codification schemes. Finally, this work also addresses some aspects related to quality of service (QoS) and flexibility of the OCDMA technology in optical communications systems.
Huang, Hu. "Multicarrier DS/SFH-CDMA systems /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22053839.
Full textWoodward, Graeme Kenneth. "Adaptive detection for DS-CDMA." Thesis, The University of Sydney, 1999. https://hdl.handle.net/2123/27691.
Full textHu, Teck Hon 1965. "A multirate DS-CDMA system." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282425.
Full textKejík, Petr. "Optimalizace přístupu do CDMA sítí." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-233541.
Full textBaudais, Jean-Yves. "Étude des modulations à porteuses multiples et à spectre étalé : analyse et optimisation." Phd thesis, INSA de Rennes, 2001. http://tel.archives-ouvertes.fr/tel-00009214.
Full textcombinaison permet de tirer partie de la robustesse et de l'efficacité spectrale de l'OFDM, et de la capacité d'accès multiple des techniques AMRC. Deux techniques associant l'OFDM et l'AMRC sont plus particulièrement analysées.
La première technique, l'AMRC à porteuses multiples est étudiée sur un canal de Rayleigh à trajets multiples. En réception, plusieurs techniques d'égalisation ou de traitement de diversité sont mises en oeuvre et une approche plus globale de la détection est proposée. Elle consiste à intégrer la fonction de désétalement dans le processus d'égalisation, permettant ainsi d'améliorer la fiabilité de la détection. Ces techniques d'égalisation sont insérées et combinées de différentes façons dans des structures d'annulation d'interférences.
Si le système AMRC à porteuses multiples est généralement proposé pour des liaisons synchrones ou quasi-synchrones, le système AMRC
multipilote peut être utilisé dans un contexte asynchrone. Les performances théoriques de ce système sont développées et comparées aux performances des systèmes AMRC à porteuse unique.
Qin, Qin. "Linear Prediction Approach for Blind Multiuser Detection in Multicarrier CDMA Systems." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1034355893.
Full textXiao, Lin. "CDMA Bus lane : cross-layer protocol for Qos routing in CDMA based mobile ad hoc networks." Thesis, Queen Mary, University of London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498195.
Full textAlam, Fakhrul. "Simulation of Third Generation CDMA Systems." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/36387.
Full textMaster of Science
Rupf, Marcel. "Coding for CDMA channels and capacity /." Zürich, 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10398.
Full textLundqvist, Henrik. "Error Correction Coding for Optical CDMA." Licentiate thesis, KTH, Microelectronics and Information Technology, IMIT, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1637.
Full textThe optical fiber is a very attractive communication mediumsince it offers a large bandwidth and low attenuation and cantherefore facilitate demanding services such as high-qualityvideo transmission. As the reach of optical fiber is beingextended to the access network it is economically attractive toshare fibers between different users without adding activecomponents in the network. The most common multiple accessmethod for such passive optical networks is time divisionmultiple access (TDMA), but lately there has been an increasedinterest in using wavelength division multiple access (WDMA)and optical code division multiple access (OCDMA). This thesisevaluates forward error correction as a method to improve theperformance of passive optical networks, in particular OCDMAnetworks.
Most studies of OCDMA use simple channel models focusingonly on the multiple access interference. However, beat noiseis the main performance limitation for many implementations ofOCDMA. Beat noise occurs when multiple optical fields areincident on a receiver, because of the square-law detection. Tomake a realistic evaluation of OCDMA, channel models which takeinterference, beat noise and other noise types into account arestudied in this thesis. Both direct sequencing CDMA and fastfrequency hopping are considered as spreading methods. Anefficient simulation method was developed in order to simulatesystems with forward error correction (FEC) and soft decoding.The simulations show that the performance is significantlyoverestimated when the beat noise is neglected. In order todecrease the error rate without using overly complex equipmentthe bandwidth has to be increased. Simulation results show thatit is beneficial to use error correction codes in addition tospreading codes for the bandwidth expansion. The efficiency canbe further improved by using soft decoding; therefore maximumlikelihood decoding methods for the OCDMA channels aredeveloped and demonstrate a significant reduction in the errorrate. Frequency hopping and direct sequencing are also comparedwith each other, and the results show that temporally codedOCDMA is more sensitive to beat noise.
In addition, the performance of a low complexity softdecoding method for Reed-Solomon codes is evaluated. Softdecoding of Reed Solomon codes has not yet found practical usebecause the earlier proposed methods do not offer sufficientperformance gains to motivate the increased complexity. Thebit-level Chase-decoding algorithm evaluated here can be easilyimplemented using any algebraic decoder.
Hakyemez, Serkan Ender. "Scheduling Algorithms For Wireless Cdma Networks." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609050/index.pdf.
Full textKatz, M. (Marcos). "Code acquisition in advanced CDMA networks." Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:9514268849.
Full textLatva-aho, M. (Matti). "Advanced receivers for wideband CDMA systems." Doctoral thesis, University of Oulu, 1998. http://urn.fi/urn:isbn:9514250397.
Full textArdebilipour, Mehrdad. "Acquisition techniques for mobile CDMA systems." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/843192/.
Full textLim, Leycheoh. "Chip interleaving for CDMA cellular systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29414.pdf.
Full textLi, Haiyan. "Power control in cellular CDMA systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0028/MQ27018.pdf.
Full textWu, Xiao Wen. "Video transmission over wireless CDMA networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0026/MQ27027.pdf.
Full textGao, Zhimin. "Radio location in urban CDMA macrocells." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0028/MQ51344.pdf.
Full textLei, Sihong. "Capacity analysis for a CDMA system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0025/MQ51740.pdf.
Full textOyefuga, Oladipupo Olaseni. "Downlink optimisation for wideband CDMA systems." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414589.
Full textHuang, Li-Ke. "Space-time DS-CDMA communication systems." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397681.
Full textDimitriou, Nikos. "Call admission control for multimedia CDMA." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/930/.
Full textDhomeja, Sheyam Lal. "CDMA communications over wireless infrared channels." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287004.
Full textLee, Chin-Chun. "CDMA for cellular mobile radio systems." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240979.
Full textOon, Tik bin. "Multiple access interference cancellation for CDMA." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242678.
Full textYan, Kai. "Genetic algorithm assisted CDMA multiuser detection." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343015.
Full textShakya, Indu Lal. "High capacity CDMA and collaborative techniques." Thesis, University of Sussex, 2008. http://sro.sussex.ac.uk/id/eprint/7619/.
Full textMozaffaripour, M. "Multiuser detection for mobile CDMA systems." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/844233/.
Full textKhanfouci, Mourad. "Séquences chaotiques pour les systèmes CDMA." Paris 11, 2005. http://www.theses.fr/2005PA112019.
Full textThe research presented in this dissertation concerns the spreading sequences optimization issues of the asynchronous DS-CDMA communication systems. After the descrption of the main classicla sequences families, based on linear feedback shift registers and optimized by the means of the minimization of maximal correlation parameters, defined on the sequence set, we have proposed a new spreading sequences design methodology that relies on the minimization of the second order statistics of the multiple access interference. We have proposed an implementation of the optimal sequences by the means of quantized chaotic (10,2)-Markovian sequences. The thesis is organized into three main topics. In the first one, we have proposed and validated the (10,2)- Markovian sequences by intensive C++ object oriented programming. In the second, we have illustrated the performances of the proposed sequences design for asynchronous DS-CDMA systems employing a linear multiuser detection front end. In the third, we have illustrated the error performances of multicode DS-CDMA systems employing the (10,2)- Markovian sequences as channelization codes. The results of the work are showing that the proposed sequences are superior to the classical spreading/channelization solutions both in terms of error performances and capacity, evaluated in terms of the available users for a target bit error rate
Abdi, Moussa. "Détection multi-utilisateurs en mode CDMA." Paris, ENST, 2002. http://www.theses.fr/2002ENST0027.
Full textPhasouliotis, Antonis. "Multicarrier CDMA systems with MIMO technology." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/multicarrier-cdma-systems-with-mimo-technology(87853579-fae7-45cb-b243-abe731f2c786).html.
Full textWu, Xiao Wen Carleton University Dissertation Engineering Systems and Computer. "Video transmission over wireless CDMA networks." Ottawa, 1997.
Find full textLi, Haiyan Carleton University Dissertation Engineering Systems and Computer. "Power control in cellular CDMA systems." Ottawa, 1997.
Find full textAgashe, Parag. "Selective cancellation of interference for CDMA." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-11182008-063200/.
Full textAbdi, Moussa. "Détection multi-utilisateurs en mode CDMA /." Paris : École nationale supérieure des télécommunications, 2003. http://catalogue.bnf.fr/ark:/12148/cb390325301.
Full text