Teses / dissertações sobre o tema "Affine Frequency Division Multiplexing"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Affine Frequency Division Multiplexing".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
Bemani, Ali. "Affine Frequency Division Multiplexing (AFDM) for Wireless Communications". Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS610.pdf.
Texto completo da fonteIn the realm of next-generation wireless systems (beyond 5G/6G), the vision is clear: to support a broad range of services and applications. This includes ensuring reliable communications in environments marked by high mobility, such as high-speed railway systems and various vehicular communications. Despite the deployment of various multicarrier techniques like orthogonal frequency division multiplexing (OFDM) and single-carrier frequency division multiple access (SC-FDMA) in standardized communication systems, the challenge persists. These techniques, while effective in time-invariant frequency selective channels, face performance degradation in high mobility scenarios due to the destruction of orthogonality among subcarriers caused by significant Doppler frequency shifts. Addressing this, the search for new, robust modulation techniques is paramount. It stands as a key area of investigation aiming to resolve the reliable communications issue for next-generation wireless networks within doubly-selective wireless channels. In this thesis, a novel solution, affine frequency division multiplexing (AFDM), is proposed. This new chirp-based multicarrier waveform is based on the discrete affine Fourier transform (DAFT), a variant of the discrete Fourier transform characterized with two parameters that can be adapted to better cope with doubly dispersive channels. This thesis provides a comprehensive investigation into the principles of AFDM within high mobility communications. It provides insight into the explicit input-output relation in the DAFT domain, unveiling the consequential impact of AFDM parameters. The manuscript details the precise setting of DAFT parameters, ensuring a full delay-Doppler representation of the channel. Through analytical demonstrations, it asserts that AFDM optimally achieves the diversity order in doubly dispersive channels due to its full delay-Doppler representation. The thesis also proposes two low-complexity detection algorithms for AFDM, taking advantage of its inherent channel sparsity. The first is a low complexity MMSE detector based on LDL factorization. The second is a low complexity iterative decision feedback equalizer (DFE) based on weighted maximal ratio combining (MRC) of the channel impaired input symbols received from different paths. Additionally, the thesis presents an embedded channel estimation strategy for AFDM systems, leveraging AFDM's ability to achieve full delay-Doppler representation of the channel. In this approach, an AFDM frame contains a pilot symbol and data symbols, with zero-padded symbols employed as guard intervals to prevent interference. A practical channel estimation algorithm based on an approximate maximum likelihood (ML) approach and compatible with this pilot scheme is also provided. The thesis concludes by delving into the expanded applications of AFDM, specifically in integrated sensing and communication (ISAC) and extremely high frequency (EHF) band communications. It is demonstrated that to identify all delay and Doppler components linked with the propagation medium, one can use either the full AFDM signal or only its pilot part consisting of one DAFT domain symbol and its guard interval. Furthermore, the chirp nature of AFDM allows for unique and simple self-interference cancellation with a single pilot, eliminating the need for costly full-duplex methods. The thesis also highlights AFDM's efficient performance in high-frequency bands (with or without mobility), where the maximal spreading of its signal in time and frequency ensures a coverage gain. Unlike other waveforms, AFDM not only provides maximal time-frequency spreading but also ensures robust and efficient detection, characterized by one-tap equalization and resilience to carrier frequency offset (CFO) and phase noise
Recio, Adolfo Leon. "Spectrum-Aware Orthogonal Frequency Division Multiplexing". Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/30193.
Texto completo da fontePh. D.
Challakere, Nagaravind. "Carrier Frequency Offset Estimation for Orthogonal Frequency Division Multiplexing". DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1423.
Texto completo da fonteZhang, Hua. "Orthogonal Frequency Division Multiplexing for Wireless Communications". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4960.
Texto completo da fonteKim, Dukhyun. "Orthogonal frequency division multiplexing for digital broadcasting". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/13704.
Texto completo da fonteBledowski, Ian A. "Frequency-division-multiplexing technique for imaging metrology". Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9286.
Texto completo da fonteClark, Alan. "On Coding for Orthogonal Frequency Division Multiplexing Systems". Thesis, University of Canterbury. Electrical and Computer Engineering, 2006. http://hdl.handle.net/10092/1092.
Texto completo da fonte李世榮 e Sai-weng Lei. "Adaptive interleaving for orthogonal frequency division multiplexing systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31224702.
Texto completo da fonteLepley, Jason J. "Frequency stabilisation for dense wavelength division multiplexing systems". Thesis, University of Essex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310059.
Texto completo da fonteWang, Samuel Y. "Perfect shuffle optical frequency division multiplexing (PS/OFDM)". Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/14255.
Texto completo da fonteBouziane, R. "Real-time optical orthogonal frequency division multiplexing transceivers". Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1383794/.
Texto completo da fonteOmomukuyo, O. O. "Orthogonal frequency division multiplexing for optical access networks". Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1400463/.
Texto completo da fonteLei, Sai-weng. "Adaptive interleaving for orthogonal frequency division multiplexing systems /". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23295065.
Texto completo da fonteCai, Kun, e 蔡琨. "Bayesian carrier frequency offset estimation in orthogonal frequency division multiplexing systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841367.
Texto completo da fonteCai, Kun. "Bayesian carrier frequency offset estimation in orthogonal frequency division multiplexing systems". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841367.
Texto completo da fonteRende, Deniz. "Bit-interleaved space-frequency coded modulation for orthogonal frequency-division multiplexing systems". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0006420.
Texto completo da fonteDeckert, Thomas. "Orthogonal frequency division multiplexing based medium access under rate constraints". Dresden Vogt, 2007. http://deposit.d-nb.de/cgi-bin/dokserv?id=3002150&prov=M&dok_var=1&dok_ext=htm.
Texto completo da fonteChen, Yingkan [Verfasser]. "Orthogonal Frequency-Division Multiplexing in Fiber-Optic Communication / Yingkan Chen". München : Verlag Dr. Hut, 2016. http://d-nb.info/1136601260/34.
Texto completo da fonteLi, Kai. "Fast orthogonal frequency division multiplexing (Fast-OFDM) for wireless communications". Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/17220/.
Texto completo da fonteGuan, Karen Min 1978. "Quadrature amplitude modulated codes for orthogonal frequency division multiplexing applications". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87226.
Texto completo da fonteAnsari, Ashlaghi Aria. "100 GBPS Orthogonal Frequency Division Multiplexing optical fiber communication network". Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1604879.
Texto completo da fonteOptical fiber communication has emerged as a high potential substitute for communication methods such as twisted pair and coaxial wire. The main advantage of optical fiber over previous methods is to have higher capacity of data rate transmission. The conventional types of modulation and demodulation technique, which have been used through optical fiber communication system are Wavelength Division Multiplexing (WDM) technique and Dense Wavelength Division Multiplexing (DWDM) technique so far.
In this thesis, the Orthogonal Frequency Division Multiplexing (OFDM) is applied through the modulation and demodulation parts due to some advantages over WDM and DWDM to reach to 100 Gbps data transmission. The main advantage of OFDM-optical fiber is that it only needs one optical source to modulate and one optical source to demodulate the signals at transmitter side and receiver side, which results in a reduction of the cost of the system. Also, by using the OFDM, the chromatic dispersion can be eliminated or decreased.
Simões, Gaspar Ivan. "Waveform Advancements and Synchronization Techniques for Generalized Frequency Division Multiplexing". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-201875.
Texto completo da fonteWelling, Kenneth. "Coded Orthogonal Frequency Division Multiplexing for the Multipath Fading Channel". International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608525.
Texto completo da fonteThis paper presents a mathematical model for Coded Orthogonal Frequency Division Multiplexing (COFDM) in frequency selective multipath encountered in aeronautical telemetry. The use of the fast Fourier transform (FFT) for modulation and demodulation is reviewed. Error control coding with interleaving in frequency is able to provide reliable data communications during frequency selective multipath fade events. Simulations demonstrate QPSK mapped COFDM performs well in a multipath fading environment with parameters typically encountered in aeronautical telemetry.
Lee, King F. "Space-time and space-frequency coded orthogonal frequency division multiplexing transmitter diversity techniques". Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/14981.
Texto completo da fonteWong, Kar Lun (Clarence). "Space-time-frequency channel estimation for multiple-antenna orthogonal frequency division multiplexing systems". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100244.
Texto completo da fonteThe proposed STF channel estimator reduces to a time-frequency (TF) channel estimator when no spatial correlations exist. In another perspective, the lower-dimension TF channel estimator can be viewed as an STF channel estimator with spatial correlation mismatch for space-time-frequency selective channels.
Computer simulations were performed to study the mean-square-error (MSE) behavior with different pilot parameters. We then evaluate the suitability of our STF channel estimator on a space-frequency block coded OFDM system. Bit error rate (BER) performance degradation, with respect to perfect coherent detection, is limited to less than 2 dB at a BER of 10-5 in the modified 3GPP fast-fading suburban macro environment. Modifications to the 3GPP channel involves reducing the base station angle spread to imitate a high transmit spatial correlation scenario to emphasize the benefit of exploiting spatial correlation in our STF channel estimator.
Oz, Ersoy. "A comparison of timing methods in orthogonal frequency division multiplexing (OFDM) systems". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Sep%5FOz.pdf.
Texto completo da fonteThesis Advisor(s): Roberto Cristi, Murali Tummala. Includes bibliographical references (p. 169-173). Also available online.
Chen, Jianwu, e 陳建武. "Frequency synchronization in OFDM-based systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40687338.
Texto completo da fonteChen, Jianwu. "Frequency synchronization in OFDM-based systems". Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40687338.
Texto completo da fonteKaraoglu, Bulent. "A comparison of frequency offset estimation methods in Orthogonal Frequency Division Multiplexing (OFDM) systems". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FKaraoglu.pdf.
Texto completo da fonteThesis Advisor(s): Roberto Cristi, Murali Tummala. Includes bibliographical references (p. 45-46). Also available online.
Kaur, Amandeep. "Comparison of Different Predistortion Techniques for Orthogonal Frequency Division Multiplexing Systems". Thesis, California State University, Long Beach, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13426595.
Texto completo da fonteWireless channels have significant problems like multipath fading, delay spread, frequency selective fading. Guard bands/channel equalization techniques are employed to overcome these. However, these solutions are complex and don’t solve the issue of bandwidth scarcity. Thus, Orthogonal Frequency Division Multiplexing was introduced; a special case of Frequency Division Multiplexing where orthogonal subcarriers overlap in the frequency domain using lesser bandwidth without any inter-symbol interference.
The next challenge is to reduce the error rate in transmission. This thesis focuses on the noise created because of the non-linear input/output relationship of the power amplifier used. Different techniques used to linearize power amplifiers are compared. Predistortion was found to be most effective. Various predistortion schemes are compared and error rate performance evaluated for the Orthogonal Frequency Division Multiplexing system with and without Predistortion as well as for different modulation techniques. Dynamic Digital Predistortion paired with 8 Quadrature Amplitude Modulation was found to work most efficiently.
Mohamed, Salma Darwish Abd Elaziz. "Modified Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (MACO-OFDM) system". Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25820.
Texto completo da fonteAcácio, Luís Carlos Lorenzo. "Equalização pré-FFT de sistemas baseados em orthogonal frequency-division multiplexing". Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-17122004-154902/.
Texto completo da fonteThis dissertation deals with time-domain equalization of digital communications systems based on orthoghonal frequency-division multiplexing (OFDM), usually referred as pre-FFT equalization in the technical literature. Such systems were originally designed to require no time equalization but can profit from its use, as is shown in this work. An uncoded simulator of the OFDM-based European system for terrestrial digital television transmission, the digital video broadcasting (DVB-T), was implemented in software. Many simulations were run to compare the performance of the traditional DVB-T reception method with the equalized version proposed. Several digital signal processing techniques were used to simulate as diverse fenomena as: generation of the source signal, effect of multipath communications channels, presence of additive white Gaussian noise, LMS (Least Mean Square) equalization, among others. In order to develop a solid base, the work includes mathematical studies about the general OFDM theory, models of communications channels and the basic principle of operation of the LMS algorithm. Since the DVB-T was used as a practical study case, a technical description of the system is presented, in which many problems and aspects about its generation and reception are discussed. To provide the reader with a historical and technological insight on the subject, this work also includes a summary of the landmarks in the development of the OFDM since the first experiments.
Hosseinpour, Ali. "Investigation of orthogonal frequency division multiplexing based Power Line Communication systems". Thesis, University of East London, 2015. http://roar.uel.ac.uk/4420/.
Texto completo da fonteErdogan, Ahmet Yasin. "Analysis of the effects of phase noise and frequency offest in orthogonal frequency division multiplexing (OFDM) systems /". Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FErdogan.pdf.
Texto completo da fonteThesis advisor(s): Murali Tummala, Roberto Cristi. Includes bibliographical references (p. 127-129). Also available online.
Holder, Sade A. "Linear frequency modulated signals vs orthogonal frequency division multiplexing signals for synthetic aperture radar systems". Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/42647.
Texto completo da fonteThe goal of this thesis is to investigate the effects of an orthogonal frequency-division multiplexing (OFDM) signal versus a linear frequency modulated or chirp signal on simulated synthetic aperture radar (SAR) imagery. Various parameters of the transmitted signal, such as pulse duration, transmitted signal energy, bandwidth, and (specifically for the OFDM signal) number of subcarriers and transmission scheme were examined to determine which parameters are most important to reconstructing a SAR image. Matched filtering and interpolation are two techniques used to reconstruct the SAR image. SAR systems are used in various military and civilian sector applications. Some SAR application examples include ground surveillance, reconnaissance and remote sensing. These applications demand high resolution imagery; therefore, knowledge of exactly which parameters of the transmitted radar signal are more important in producing fine resolution imagery is worth investigating. This research will also aid in providing flexibility in terms of what type of signal and signal parameters are best suited for a particular SAR application and associated military missions. In addition to improving the method attaining high resolution images, SAR process improvement can potentially reduce military SAR system design cost.
Holguín-Sánchez, Fausto Daniel. "Spectral Shape Division Multiplexing (SSDM): Apparatus, Transmitter, Receiver and Detection". DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/800.
Texto completo da fonteEscayola, Elias Francesc Xavier. "Next generation passive optical networks based on orthogonal frequency division multiplexing techniques". Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/334417.
Texto completo da fonteEn estas últimas décadas, la industria de las comunicaciones ha adquirido gran importancia y hoy en día, constituye una herramienta imprescindible para el funcionamiento en la sociedad de la información. Así pues, el crecimiento exponencial en la demanda de servicios de banda ancha y la carga de información cada vez mayor que se necesita transmitir ha estimulado la evolución de las infraestructuras del tramo de acceso a la red para poder satisfacer las necesidades del usuario de forma efectiva en términos de costes de instalación y de mantenimiento. Las redes ópticas pasivas (Passive Optical Networks, PON) son actualmente consideradas la alternativa más eficiente y de menor coste para desplegar fibra hasta los hogares. Con el fin de permitir que muchos usuarios coexistan simultáneamente se han desarrollado PONs basadas en multiplexación en tiempo (Time Division Multiplexing Access, TDMA). De cara al futuro, sin embargo, se prevé que estas técnicas no permitan cubrir las exigencias sobre las redes de acceso. En consecuencia, otras técnicas de acceso múltiple al medio como el acceso múltiple por división de longitud de onda (Wavelength Division Multiplexing Access, WDMA) o el acceso múltiple por división de frecuencia ortogonal (Orthogonal Frequency Division Multiplexing Access, OFDMA) se encuentran actualmente en proceso de estudio y desarrollo para su uso en la futura generación de PONs. En concreto, en los últimos años OFDM se ha destacado entre la comunidad científica al considerarse una solución con gran potencial para su futura implantación en redes de acceso pasivas. Esto es especialmente cierto debido a la capacidad que el OFDM para trabajar con modulaciones multinivel, así como su alta tolerancia a la dispersión cromática y a la gran flexibilidad y granularidad que posibilita en términos de gestión del ancho de banda. Por todo lo anterior, el objetivo de esta Tesis es estudiar con profundidad las ventajas y los retos de aplicar el estándar OFDM como solución de red de acceso; del mismo modo, ofrece soluciones para mejorar su rendimiento. Con el objetivo de evaluar las principales estructuras basadas en OFDM-PON, en primer lugar se realiza un análisis comparativo de todas ellas destacando sus niveles de sensibilidad, máximo alcance y número de usuarios. Un aspecto fundamental para los proveedores de red es el coste de operación, despliegue y mantenimiento de las redes. Como solución de bajo coste, esta Tesis propone un modelo de red llamado Statistical-OFDMA-PON que se basa en modulación de intensidad y detección directa. Además, este modelo se completa con estrategias de gestión dinámica del ancho de banda de los usuarios que conforman la estructura de red propuesta consiguiendo una mejora en el balance de potencias que permite aumentar distancia y número de usuarios. Uno de los principales problemas del OFDM es el alto nivel de la relación de potencia de pico a potencia media (Peak-to-Average Power Ratio, PAPR) creciente con el número de portadoras. Esta Tesis propone un nuevo algoritmo basado en el pliegue de la señal y la transmisión de información auxiliar para compensar el efecto del PAPR aumentando así la sensibilidad del sistema óptico. Por otro lado, OFDMA requiere un número elevado de operaciones en el dominio digital resultando en un alto esfuerzo computacional que a su vez se traduce en un aumento del coste. Por esta razón, esta Tesis presenta un estudio sobre la optimización de la resolución requerida en los conversores analógicodigital (Digital-to-Analog/Analog-to-Digital Converters, DAC/ADCs) manteniendo la calidad de transmisión. La optimización del tiempo de cómputo requerido puede dotar de un mayor atractivo la solución de red óptica basada en OFDMA. Finalmente, otro de los problemas que presentan las redes ópticas OFDM es su sensibilidad frente al ruido de fase (Phase Noise, PN). En este aspecto, esta Tesis presenta un estudio del efecto del ancho de línea del láser y su dependencia con el ancho de banda de la señal. Técnicas de mitigación basadas en tonos piloto han sido implementadas y se han encontrado los valores limitantes del ancho de línea dentro del alcance de los láseres de bajo coste.
Shenoy, Dinesh Nandakumar. "Compressive Sensing| Performance of Sparse Channel Estimation in Orthogonal Frequency Division Multiplexing". Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10751778.
Texto completo da fonteCompressive Sensing is a signal processing technique that is based on the property that the sparsity concept of a given signal can be exploited to reconstruct the signal successfully while disobeying Shannon’s Nyquist Theorem with fewer samples than what is required.
Sparse estimation which is an application of Compressive Sensing is applied to an OFDM transmission, as the model provides a better performance along with controlled inter symbol interference (ISI).
The thesis is based on the assumption that a single OFDM block is essentially time invariant and the simulations are carried out based on these assumptions. This thesis uses training data to simulate the channel estimation and to successfully recover the transmitted information. Convex optimization techniques to minimize noise and obtain the transmitted signal are employed. The thesis estimates the bit error rate (BER) using a Rayleigh channel and AWGN to illustrate how sparse estimation can be used to increase the performance of the system. The BER is estimated using the output at the receiver end and then compared with the BER of Least Square Estimation technique.
Simulation results show that the BER results for a system based on Sparse estimation of the channel are much better than a system with Least Square Estimation at high signal to noise ratios (SNR).
Schedler, Stephan [Verfasser]. "Generalized Frequency Division Multiplexing in the Two-Way-Relay Channel / Stephan Schedler". Aachen : Shaker, 2016. http://d-nb.info/1120863880/34.
Texto completo da fonteCraven, Michael P. "Inter-chip communications in an analogue neural network utilising frequency division multiplexing". Thesis, University of Nottingham, 1994. http://eprints.nottingham.ac.uk/13085/.
Texto completo da fonteRajanna, Sowmya. "Orthogonal Frequency Division Multiplexing (OFDM) channel estimation using pilot based parametric scheme". Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10011270.
Texto completo da fonteThis paper is aimed at parametric Multiple Input Multiple Output (MIMO) ? Orthogonal Frequency Division Multiplexing (OFDM) channel estimation that increases the spectrum efficiency of the wireless communication systems. OFDM technology has been widely used due to its high data rate and low multipath distortion. The estimation of channel for OFDM is required in vehicular environments and many other cutting-edge technology applications. To develop such reliable vehicular wireless communication systems, it is necessary to set up the standards and models of propagation channel with respect to the environment and scenarios. The proposed parametric scheme can accomplish super resolution by assessing the delays in arbitrary paths, making this scheme more suitable for wireless channels. The channel estimation precision is increased by using the spatial and temporal correlations in the wireless MIMO channel. The average pilot overhead for each antenna is reduced because of the temporal correlation of MIMO channels. Thus, the parametric scheme is promising for future wireless technologies as it accomplishes better spectral efficiency and better robustness for the multipath fading channels.
Sahmel, Peter H. "Eigenspace Approach to Specific Emitter Identification of Orthogonal Frequency Division Multiplexing Signals". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35987.
Texto completo da fonteMaster of Science
Du, Jinfeng. "Pulse Shape Adaptation and Channel Estimation in Generalised Frequency Division Multiplexing Systems". Licentiate thesis, Stockholm : Informations- och kommunikationsteknik, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9457.
Texto completo da fonteGemechu, Wasyhun Asefa. "Comparison of nonlinear frequency division multiplexing and OFDM for optical fiber transmissions". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT021/document.
Texto completo da fonteNonlinear effects in optical fiber set the ultimate limit to the channel capacity in long-haul optical transmission systems. Advanced nonlinear compensation techniques such as digital backpropagation (DBP) have been proposed as a solution to overcome the channel capacity crunch. However, given theircomputational complexity, in a practical environment their performance gainremains very limited. This triggered a search for a novel communication system design that takes fiber nonlinearity into consideration. A new nonlinearcommunication method, based on the theory of the inverse spectral transform, has been proposed to overcome the nonlinear capacity crunch. Thismethod, originally proposed by Hasegawa in 1993 and called eigenvalue (ormulti-soliton) communication, is based on the fundamental observation thatthe nonlinear spectrum of an optical signal is invariant (except for a triviallinear phase shift) upon propagation in the fiber channel, as described bythe nonlinear Schrödinger equation (NLSE). This means that if the directspectral transform (also known as nonlinear Fourier transform (NFT)) ofthe received signal can be computed, the eigenvalue spectrum can be fullyrecovered.This thesis focuses on a NFT-based communication technique known as nonlinear frequency division multiplexing (NFDM). The NFDM optical systemis numerically assessed and experimentally demonstrated. First, the structure of the proposed single-polarization NFDM system using the continuousspectrum in the normal dispersion regime is presented. To that end, theNFT of the vector NLSE, or Manakov system, was numerically developed.Based on these algorithms the NFDM method was extended to polarizationdivision multiplexed (PMD) systems, and experimentally validated for thefirst time using the continuous spectrum. Finally, the experiment will bereplicated in the anomalous dispersion regime.Additional numerical studies are presented, in order to investigate the implementation challenges of the proposed NFDM techniques for the continuousspectrum modulation
Leung, Edward Sau-Yee. "A successive interference cancelling receiver for orthogonal frequency division multiplexing in mobile communications". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0019/MQ37576.pdf.
Texto completo da fonteYang, Runfeng. "Multiband orthogonal frequency division multiplexing modulation and demodulation for wireless universal serial bus". Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499368.
Texto completo da fonteBagdiya, Anshul P. "Iterative receiver for flip orthogonal frequency division multiplexing and proposed 5G modulation techniques". Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10251768.
Texto completo da fonteIn Optical Wireless Communication (OWC) systems, the technique of Flip-Orthogonal Frequency Division Multiplexing (Flip-OFDM) is applied, where the positive segment and negative segment of the signal are transmitted on two continuous OFDM sub-frames. Conventionally in Flip-OFDM, data is recovered by simply subtracting the negative sub-frame from the positive sub-frame. But the signal survey confirms that the information in both sub-frames gets disrupted during signal propagation and an incorrect detection of the received values takes place at the detector.
An iterative receiver is proposed that utilizes the input signal values along with the received signals sub-frames to improve the efficacy of the Flip-OFDM. The Matlab software is used to design the transmitter and iterative receiver. Features such as cyclic prefixing, frame multiplexing, and channel characterization are included in the design.
The results of the simulation depict that the suggested receiver delivers a superior Bit Error Rate (BER) and Signal to Noise Ratio (SNR) gain when compared to the conservative receiver.
Neilson, Rob. "An investigation into the use of orthogonal frequency division multiplexing in packet radio". Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/5139.
Texto completo da fonteThe concept of Orthogonal Frequency Division Multiplexing has been around since the 1960s. It has resurfaced over the last decade as being the modulation scheme of choice in some newer technologies like Digital Video Broadcasting (DVB) and Asynchronous Digital Subscriber lines (ADSL). Amateur packet radio started in 1978 and has attracted thousands of enthusiasts from around the world. The interest in packet radio has waned over the years due advances in the data transmission capabilities oflandline systems and also more widespread access to the Internet. The purpose of this thesis was to develop a simple software simulation model to determine whether or not OFDM could be used to increase the data rates currently available in packet radio systems. The thesis starts out with an introduction to packet radio and OFDM in Chapter 1. A slightly more detailed discussion on OFDM is given in Chapter 2 in order to develop a basic specification for the proposed OFDM model. Chapters 2,3 and 4 discuss the development of the Transmitter model, the Receiver model and the Channel model respectively using the Simulink software package. Chapter 6 discusses the problem of Peak-to-Average Power Ratios (PAPR) in OFDM and explores the use of A-law companding to reduce this problem. In Chapter 7, the developed models are simulated and their performance compared to theoretical expectations. The full system is also simulated in this chapter in order to ascertain the possible data rate through the modelled packet radio channel. Conclusions regarding the application of OFDM to packet radio are presented in Chapter 8.
Paul, Prabal. "On The Peak-To-Average-Power-Ratio Of Affine Linear Codes". Thesis, 2006. https://etd.iisc.ac.in/handle/2005/350.
Texto completo da fontePaul, Prabal. "On The Peak-To-Average-Power-Ratio Of Affine Linear Codes". Thesis, 2006. http://hdl.handle.net/2005/350.
Texto completo da fonte