Дисертації з теми "Frequency coded"
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Ilunga, Lou. "Adaptive, Turbo-coded OFDM." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34578.
Повний текст джерела
In this thesis, we enhance the system throughput of a working OFDM system by adding turbo coding and adaptive modulation (AD). Simulation is done over a time varying, frequency selective Rayleigh fading channel. The temporal variations in the simulated wireless channel are due to the presence of Doppler, a sign of relative motion between transmitter and receiver. The wideband system has 48 data sub-channels, each is individually modulated according to channel state information acquired during the previous burst. The end goal is to increase the system throughput while maintaining system performance under a bit error
rate (BER) of 10-2. The results we obtained are preliminary. The lack of resources prevented us from producing detailed graphs of our findings.
Master of Science
Gallagher, Daniel. "ULTRA-WIDEBAND ORTHOGONAL FREQUENCY CODED SAW CORRELATORS." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3950.
Повний текст джерелаM.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
Wilson, William. "Multifunctional Orthogonally-Frequency-Coded Saw Strain Sensor." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3157.
Повний текст джерелаRice, Michael, and Kenneth Welling. "CODED OFDM FOR AERONAUTICAL TELEMETRY." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606496.
Повний текст джерелаThree Quadrature Phase Shift Keying (QPSK) mapped COFDM systems demonstrating a continuum of complexity levels are simulated over an evolving three ray model of the multipath fading channel with parameters interpolated from actual channel sounding experiments. The first COFDM system uses coherent QPSK and convolutional coding with interleaving in frequency, channel equalization and soft decision decoding; the second uses convolutional coding with interleaving in frequency, Differential Phase Shift Keying (DPSK) and soft decision decoding; the third system uses a quaternary BCH code with DPSK mapping and Error and Erasure Decoding (EED). All three systems are shown to be able to provide reliable data communication during frequency selective fade events. Simulations demonstrate QPSK mapped COFDM with reasonable complexity performs well in a multipath frequency selective fading environment under parameters typically encountered in aeronautical telemetry.
Rende, 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.
Повний текст джерелаXAVIER, GUILHERME BARRETO. "MODULATION SCHEMES FOR FREQUENCY CODED QUANTUM KEY DISTRIBUTION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6483@1.
Повний текст джерелаA criptografia quântica foi proposta como uma solução para o problema da distribuição de chaves criptográficas com segurança total garantida pelos princípios da mecânica quântica. Através dessa técnica é possível saber se um espião tentou interceptar a transmissão, o que é impossível utilizando técnicas de transmissão clássicas. Nesse trabalho foi feito um breve resumo da teoria de criptografia quântica, de suas técnicas de transmissão e dos problemas tecnológicos enfrentados. Foi analisada em detalhes a técnica de transmissão de qubits utilizando codificação de freqüência e feita uma comparação dos diferentes esquemas de modulação frente aos protocolos BB84 e B92. Foi demonstrado que os dois esquemas de modulação existentes (AM-AM e PM-PM) são na realidade equivalentes e foi proposto um novo esquema, o AM-PM o único que suporta o protocolo BB84 clássico. Medidas foram realizadas classicamente nos formatos AM-AM e AM-PM.
Quantum cryptography has been proposed as a solution to the cryptographic key distribution problem with absolute security guaranteed by the principles of quantum mechanics. Through this scheme it is possible to find out whether a spy tried to eavesdrop on the transmission, which was impossible to discover using classical transmission techniques. In this work a brief review of quantum cryptography theory, transmission techniques and technological problems involved were performed. It was analyzed in detail the transmission technique employing frequency coding, and a comparison was made between the different modulation schemes and the BB84 and B92 protocols. It was demonstrated that the two existing modulation formats (AM-AM and PM-PM) are in fact equivalent and a new format (AM-PM) was proposed, the only one able to accommodate classical BB84. Classical measurements were performed on the AM-AM and AMPM formats.
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.
Повний текст джерелаPham, Tri. "Soft Detection of Trellis Coded CPM in Frequency-SelectiveChannels." Thesis, University of Canterbury. Electrical and Electronic Engineering, 2012. http://hdl.handle.net/10092/7178.
Повний текст джерелаRattray, George G. K. "Joint diversity trellis-coded modulation for frequency selective environments." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366060.
Повний текст джерелаBelezinis, P. "The performance of time-frequency coded spread-spectrum systems." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/37943.
Повний текст джерелаZheng, Jun. "Analysis of coded OFDM system over frequency-selective fading channels." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/1137.
Повний текст джерелаSILVA, THIAGO FERREIRA DA. "OPTICAL TRANSMISSION OF FREQUENCY-CODED QUANTUM BITS WITH WDM SYNCHRONIZATION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=11742@1.
Повний текст джерелаFUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
A criptografia quântica se apresenta como uma área relativamente nova e interdisciplinar que, fundamentada nas leis da mecânica quântica, promete solucionar o grande desafio da criptografia simétrica clássica atual, a distribuição de chaves. A distribuição quântica de chaves provê comunicação absolutamente segura entre duas partes, possibilitando o compartilhamento de um segredo, que será utilizado na posterior encriptação da mensagem. Esta dissertação relata a implementação física experimental de um sistema óptico de distribuição quântica de chaves com codificação em freqüência por dupla-modulação em amplitude e fase e sincronização por multiplexação no domínio do comprimento de onda. São introduzidos os conceitos teóricos básicos necessários ao desenvolvimento do tema e apresentadas medições de caracterização dos principais componentes do sistema, bem como resultados de medidas sistêmicas clássicas e quânticas.
The quantum cryptography rises as a relatively new and interdisciplinary area that, grounded in the quantum mechanics laws, promises to solve the major challenge in the actual symmetric classical cryptography, the key distribution. The quantum key distribution enables absolutely secure communication between two parts, making them able to share a secret that will be used in the posterior message encryptation. This dissertation reports the experimental physical implementation of an optical quantum key distribution system with frequency coding by amplitude and phase double-modulation process and wavelengthdivision multiplexing synchronization. The mean theoretical foundations are briefly introduced and the characterization measurements of the most important devices are shown, as like results from systemic classical and quantum measurements.
Welling, Kenneth. "Coded Orthogonal Frequency Division Multiplexing for the Multipath Fading Channel." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608525.
Повний текст джерелаThis 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.
Caldera, Manora K. "Combined coding and modulation in frequency-selective mobile communications." Thesis, Curtin University, 2000. http://hdl.handle.net/20.500.11937/2493.
Повний текст джерелаSantos, Bianca Maria. "SAW REFLECTIVE TRANSDUCERS AND ANTENNAS FOR ORTHOGONAL FREQUENCY CODED SAW SENSORS." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3433.
Повний текст джерелаM.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
Pelekanakis, Konstantinos. "Harvesting time-frequency-space diversity with coded modulation for underwater acoustic communications." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50587.
Повний текст джерелаIncludes bibliographical references (leaves 172-180).
The goal of this thesis is to design a low-complexity, high data-rate acoustic communications system with robust performance under various channel conditions. The need for robust performance emerges because underwater acoustic (UWA) channels have time-varying statistics, thus a coded modulation scheme optimally designed for a specific channel model will be suboptimal when the channel statistics change. A robust approach should use a coded modulation scheme that provides good performance in both additive white Gaussian noise (AWGN) and Rayleigh fading channels (and, consequently in the Rice fading channel, an intermediate channel model between the latter two). Hence, high data-rate coded modulation schemes should exhibit both large free Euclidean and Hamming distances. In addition, coded modulation is regarded as a way to achieve time diversity over interleaved flat fading channels. UWA channels offer additional diversity gains in both frequency and space; therefore a system that exploits diversity in all three domains is highly desirable. Two systems with the same bit-rate and complexity but different free Euclidean and Hamming distances are designed and compared. The first system combines Trellis Coded Modulation (TCM) based on an 8-PSK signal set, symbol interleaving and orthogonal frequency-division multiplexing (OFDM). The second system combines bit-interleaved coded modulation (BICM), based on a convolutional code and a 16-QAM signal set, with OFDM.
(cont.) Both systems are combined with specific space-time block codes (STBC) when two or three transmit antennas are used. Moreover, pilot-symbol-aided channel estimation is performed by using a robust 2-D Wiener filter, which copes with channel model mismatch by employing appropriate time and frequency correlation functions. The following result was obtained by testing the aforementioned systems using both simulated and experimental data from RACE '08: the BICM scheme performs better when the UWA channel exhibits limited spatial diversity. This result implies that coded modulation schemes emphasizing higher Hamming distances are preferred when there is no option for many receive/transmit hydrophones. The TCM scheme, on the other hand, becomes a better choice when the UWA channel demonstrates a high spatial diversity order. This result implies that coded modulation schemes emphasizing higher free Euclidean distances are preferred when multiple receive/transmit hydrophones are deployed.
by Konstantinos Pelekanakis.
Ph.D.
Caldera, Manora K. "Combined coding and modulation in frequency-selective mobile communications." Curtin University of Technology, School of Electrical and Computer Engineering, 2000. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=9820.
Повний текст джерелаare obtained under ideal sample timing and carrier recovery conditions. This has been achieved without increasing the receiver complexity based on the number of states in the Viterbi decoder, compared to the uncoded GMSK scheme. Furthermore, these coded schemes are more tolerant to sample timing and carrier phase impairments.Also, the BER performances of the proposed trellis coded GMSK schemes have been extensively investigated by computer simulations for frequency-flat and frequency-selective fading channels. In the case of frequency-selective fading, the Viterbi decoding is made adaptive to cater for the channel impulse response variations with time. With this adaptive receiver, the irreducible BERs of the coded scheme is found to be lower than that of the uncoded. Performance improvements are obtained with a trellis coded GMSK scheme using a constraint length 2 code with a Viterbi decoder of 16 states compared to the 128 states required for the uncoded scheme. Further, the coded scheme has shown less sensitivity to carrier phase errors, compared to the uncoded.
Wavegedara, Kapila Chandika B. "Advanced receivers for space-time block-coded single-carrier transmissions over frequency-selective fading channels." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/620.
Повний текст джерелаZou, Ding, and Ding Zou. "FPGA-Based LDPC Coded Modulations for Optical Transport Networks." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/622985.
Повний текст джерелаAhmed, Maher Verfasser], and Thomas [Akademischer Betreuer] [Kaiser. "Realistic frequency coded chipless RFID : physically modulated tags and refectarray readers / Maher Ahmed ; Betreuer: Thomas Kaiser." Duisburg, 2017. http://d-nb.info/1147681341/34.
Повний текст джерелаAhmed, Maher Mohamed Khaliel [Verfasser], and Thomas [Akademischer Betreuer] Kaiser. "Realistic frequency coded chipless RFID : physically modulated tags and refectarray readers / Maher Ahmed ; Betreuer: Thomas Kaiser." Duisburg, 2017. http://d-nb.info/1147681341/34.
Повний текст джерелаSaldanha, Nancy. "Modeling, design and fabrication of orthogonal and psuedo-orthogonal frequency coded SAW wireless spread spectrum RFID sensor tags." Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5025.
Повний текст джерелаID: 029809657; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 148-152).
Ph.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
Akangol, Mehmet. "Target Detection By The Ambiguity Function Technique And The Conventional Fourier Transform Technique In Frequency Coded Continuous Wave Radars." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606766/index.pdf.
Повний текст джерелаRoderick, David V. "A coded orthogonal frequency division multiplexing simulation of a high data rate, line-of-sight, digital radio for mobile maritime communications." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA333326.
Повний текст джерелаBetancourt, R. Miguel A. "Coded performance of a fast frequency-hopped noncoherent BFSK ratio statistic receiver over a Rician fading channel with partial-band interference." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23568.
Повний текст джерелаA frequency-hopping binary frequency shift keying (BSFK) ratio-statistic receiver with multihops per data bit is an effective electronic counter-countermeasures (ECCM) system against partial-band jamming interference. Interference is modeled as Gaussian noise. Orthogonal binary signaling and independent fading diversity is considered over frequency-nonselective, slow fading Rayleigh, Rician, and Gaussian channels. A forward error correcting coding scheme is implemented for a 1/2 rate convolutional code algorithm. The probability of bit error is examined for different levels of diversity, thermal noise, severity of fading, fraction of bandwidth jammed, and jamming power. Uncoded and coded system comparisons are done to determine worst case performance.
Gray, Andrew, Meera Srinivasan, Marvin Simon, and Tsun-Yee Yan. "FLEXIBLE ALL-DIGITAL RECEIVER FOR BANDWIDTH EFFICIENT MODULATIONS." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608745.
Повний текст джерелаAn all-digital high data rate parallel receiver architecture developed jointly by Goddard Space Flight Center and the Jet Propulsion Laboratory is pre- sented. This receiver utilizes only a small number of high speed components along with a majority of lower speed components operating in a parallel fre- quency domain structure implementable in CMOS, and can process over 600 Mbps with numerous varieties of QPSK modulation, including those incorpo- rating precise pulse shaping for bandwidth eÆcient modulation. Performance results for this receiver for bandwidth eÆcient QPSK modulation schemes such as square-root raised cosine pulse shaped QPSK and Feher’s patented QPSK are presented, demonstrating the great degree of exibility and high performance of the receiver architecture.
Friedrich, Konrad Jens. "Development of an active SONAR platform for AUV applications in a closed environment." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20026.
Повний текст джерелаENGLISH ABSTRACT: In recent years Autonomous Underwater Vehicles (AUVs) have become interesting for harbor mapping and protection. AUVs require a SONAR sensor for observing their surroundings, thus enabling them to perform collision avoidance manoeuvres and scanning their operating environment for intruders or foreign objects, e.g. mines. To perform such actions the SONAR sensor is required to supply very fine range resolution for target imaging, as well as providing information about possible target velocity. Basic SONAR theory is discussed, as well as different approaches to signal design and processing techniques, for achieving the required resolution in range and target velocity. Two of the discussed approaches are selected for processing range and target velocity, respectively. Both approaches are simulated for their validity before being tested by using a custom-built platform. The platform is highly configurable and designed for capacity of testing a variety of SONAR signals and set ups. Furthermore, the platform is built by using off-the-shelf components to minimize development costs. The results of simulations and practical tests are presented. A high correlation between theory and practice is achieved. The knowledge and the platform presented form the stepping stone for further SONAR sensor developments.
AFRIKAANSE OPSOMMING: In die laaste jare het outonome onderwater voertuie (OOV) toenemend belangrik geword vir die kartografie en beskerming van hawens. OOV’s vereis SONAR sensore wat hulle in staat stel, om hulle omgewing waar te neem en sodoende botsing vermydings take te verrig en ook om hul werksomgewing noukeurig te skandeer om indringers of vreemde voorwerpe, bv. myne, op te spoor. Om sulke werk te verrig, word van die SONAR sensor vereis, om baie fyn afstand oplossings vir teiken te verskaf, insluitend die moontlike snelheid van die teiken. Basiese SONAR teorie word bespreek, en dan verskeie benaderings van sein ontwerp en verwerkings tegnieke. Twee van die bespreekte benaderings word gekies om afstand en teiken snelheid onderskeidelik te verwerk. Altwee benaderings word gesimuleer om hul geldigheid vas te stel, voor dat hulle getoets word op ’n pasmaat vervaardigde platform. Die platform is hoogs aanpasbaar en is ontwerp vir sy vermoë om ’n verskeidenheid SONAR seine en verwerkings te hanteer. Verder is die platform vervaardig met standard rakonderdele om ontwikkelingskoste so laag as moontlik te hou. Die uitslae van die simulerings en praktiese toetse word voorgestel. ’n Hoë mate aan korrelasie is bereik tussen teorie en praktyk. Die kennis en die platvorm, wat hier voorgestel word, vorm die eerste trappie vir toekomstige SONAR sensor ontwikkeling.
Saleh, Mahdi. "Contributions to High Range Resolution Radar Waveforms : Design of Complete Processing Chains of Various Intra-Pulse Modulated Stepped-Frequency Waveforms." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0024.
Повний текст джерелаIn various radar systems, a great deal of interest has been paid to selecting a waveformand designing a whole processing chain from the transmitter to the receiver toobtain the high range resolution profile (HRRP). For the last decades, radar designershave focused their attentions on different waveforms such as the pulse compressionwaveforms and the stepped frequency (SF) waveform:On the one hand, three different types of wide-band pulse compression waveforms havebeen proposed: the linear frequency modulation (LFM) waveform, the phase coded(PC) waveform, and the non-linear frequency modulation (NLFM) waveform. They arevery popular but the sampling frequency at the receiver is usually large. This hence requiresan expensive analog-to-digital convertor (ADC). In addition, the PC and NLFMwaveforms may be preferable in some high range resolution applications since they leadto peak sidelobe ratio (PSLR) and integrated sidelobe ratio (ISLR) better than the onesobtained with the LFM waveform.On the other hand, when dealing with SF waveforms, a small sampling frequency canbe considered, making it possible to use a cheap ADC.Pulse compression and SF waveforms can be combined to take advantage of both. Althoughthe standard combination of PC or NLFM with SF leads to the exploitation ofa cheap ADC, the performance of the PC waveform or NLFM waveform in terms ofPSLR and ISLR cannot be attained. As the PSLR and the ISLR have a great influenceon the probability of detection and probability of false alarm, our purpose in the PhDdissertation is to present two new processing chains, from the transmitter to the receiver:1) In the first approach, the spectrum of a wide-band pulse compression pulse is splitinto a predetermined number of portions. Then, the time-domain transformedversions of these various portions are transmitted. At the receiver, the receivedechoes can be either processed with a modified FD algorithm or a novel timewaveformreconstruction (TWR) algorithm. A comparative study is carried outbetween the different processing chains, from the transmitter to the receiver, thatcan be designed. Our simulations show that the performance in terms of PSLRand ISLR obtained with the TWR algorithm is better than that of the modified FDalgorithm for a certain number of portions. This comes at the expense of an additionalcomputational cost. Moreover, whatever the pulse compression used, the approach we present outperforms the standard SF waveforms in terms of PSLRand ISLR.2) In the second approach, we suggest approximating the wide-band NLFM by apiecewise linear waveform and then using it in a SF framework. Thus, a variablechirp rate SF-LFM waveform is proposed where SF is combined with a train ofLFM pulses having different chirp rates with different durations and bandwidths.The parameters of the proposed waveform are derived from the wide-band NLFMwaveform. Then, their selection is done by considering a multi-objective optimization issue taking into account the PSLR, the ISLR and the range resolution.The latter is addressed by using a genetic algorithm. Depending on the weightsused in the multi-objective criterion and the number of LFM pulses that is considered, the performance of the resulting waveforms vary.An appendix is finally provided in which additional works are presented dealing withmodel comparison based on Jeffreys divergence
Al-Ghadhban, Samir Naser. "Multi-layered Space Frequency Time Codes." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29498.
Повний текст джерелаPh. D.
Nikolakopoulos, Xenofon. "Optimum codes for FFH." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA331918.
Повний текст джерелаThesis advisors, Tri T. Ha, R. Clark Robertson. AD-A331 918. Includes bibliographical references (p. 69-70). Also available online.
Ekinci, Umut Utku. "Code Aided Frame Synchronization For Frequency Selective Channels." Thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/2/12611951/index.pdf.
Повний текст джерелаOng, Chong Tean. "Asynchronous hopping and code diversity in frequency-hopped code division multiple access systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25130.pdf.
Повний текст джерелаGuan, 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.
Повний текст джерелаMatrakidis, Chris. "Error control coding for constrained channels." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324963.
Повний текст джерелаPersson, Simon. "The correlation between code coverage, cyclomatic complexity and fault frequency." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119748.
Повний текст джерелаChu, Alice Pin-Chen. "High-Rate Space-Time Block Codes in Frequency-Selective Fading Channels." Thesis, University of Canterbury. Electrical and Computer Engineering, 2012. http://hdl.handle.net/10092/10360.
Повний текст джерелаSo, Daniel Ka Chun. "MIMO wireless communications in frequency selective fading channels /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202003%20SO.
Повний текст джерелаIncludes bibliographical references (leaves 136-144). Also available in electronic version. Access restricted to campus users.
Purle, David J. "Frequency hopped code division multiple access techniques for future wireless communications." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281833.
Повний текст джерелаKaraoglu, 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.
Повний текст джерелаThesis Advisor(s): Roberto Cristi, Murali Tummala. Includes bibliographical references (p. 45-46). Also available online.
雷靜 and Jing Lei. "Frequency synchronization methods for digital broadband receivers." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31244427.
Повний текст джерелаYu, Shu-mei, and 游淑媚. "Noncoherent Multistage Space-Frequency Coded MIMO-OFDM." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/11858280079422321776.
Повний текст джерела國立中央大學
通訊工程研究所
97
In 2005, a noncoherent space-frequency coded MIMO-OFDM scheme was proposed. But its complexity is very high if the number of tones is not small. In this thesis, we modify this scheme by using multistage decoding. All tones are divided into several groups. In each decoding stage, one group is decoded with the information of previously decoded groups and the corresponding received signals. At the transmitter, the power is also adjusted for decreasing error rates. In addition, trellis coding is utilized for further enhancing the error performance.
Botha, P. R. (Philippus Rudolph). "Iterative decoding of space-time-frequency block coded mimo concatenated with LDPH codes." Diss., 2013. http://hdl.handle.net/2263/33344.
Повний текст джерелаDissertation (MEng)--University of Pretoria, 2013.
gm2014
Electrical, Electronic and Computer Engineering
unrestricted
Akol, Roseline Nyongarwizi. "Residue number system coded differential space-time-frequency coding." Thesis, 2007. http://hdl.handle.net/10413/1542.
Повний текст джерелаThesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2007.
Hsiao, Wen-Son, and 蕭萬松. "Modified Coded Frequency/Phase Modulation in the Fading Channel." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/91056602813486973416.
Повний текст джерела中原大學
電子工程學系
82
We introduce trellis-coded modulation(TCM),used for data communication with the purpose of gaining noise immunity over uncoded transmision without altering the data rate. TCM is a combined coding and modulation scheme for improving the reliability of a digital transmission system without in increasing the transmitted power or the required bandwith. In a power-limited enviroment,the desired system performance should be achived with the smallest possible power.One solution is the use of error-correcting codes,which increase the power efficiency by adding extra bits to the transmitted symbol sequence. FPM is a scheme which combine FSK and PSK modulation and use of trellis coding and Viterbi decoding to improve error performance over uncoded modulation.The coding gain is a function of the amount of memory introduced by the encoder,i. e., the constrant length,and of signal positioning of the signal point in the signal space,i.e.,the signal constellation. FPM is so enlarge the intra-distrance of signal constellation so as to enhance coding gain. MTCM is implemented by an encoder with b binary input bits ans s binary output bits that are mapped into k M-ary symbols in each transmission interval.The parameter k is reference to as the multiplicity of the code since it represents the number of M-ary symbols allocated to each branch in the trellis diagram. The throughput is r=b/k bits/s/Hz,which,depending on the choice of b and k,may or may not be integer-valued. It is interesting to investigate,the value of trellis multiplicty k which enlarge the distance d2 as to improve coding gain. MTCM/FPM is a new scheme. It is combined two adventages which described for improved performance on the AWGN and Fading channel.
Wu, Cheng-Lung, and 吳政龍. "Space-Time-Frequency 3-Dimensional Complementary Coded CDMA Systems." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/27794907435738195888.
Повний текст джерелаChang, Feng-Yu, and 張豐裕. "Performance of Orthogonal Coded QPSK in Frequency Transmit Diversity over Frequency-selective Fading Channel." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/65245350437213474860.
Повний текст джерела國立海洋大學
導航與通訊系碩士班
91
This paper presents a QPSK performance utilizing Orthogonal Variable Spreading Factor technique and Frequency Diversity Transmits over Frequency-selective fading channel. The coherence bandwidth measured from Power Delay Profile with 3GPP Vehicular multipath channel was defined as the frequency separation between two carriers. It shows that OVSF coded QPSK with two-frequency diversity transmits (down-link) has significant improvement of BER in terms of Eb/No using MRC-Rake receiver. In addition, this orthogonal channel coding scheme can substantially mitigate the effects of co-channel interference .
Li, Yu-Tung, and 李雨桐. "Optimization of High Frequency Ultrasonic Needle Transducer System Using Coded Excitation." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/61069182755802466920.
Повний текст джерела國立陽明大學
生醫光電研究所
102
Epidural anesthesia (EA) is one of the most widely used anesthesia methods, common used on regional anesthesia, painless labor, and post-operation analgesia. The insertion of the epidural needle into the epidural space fully depends on anesthesiologist’s experience. In conducting epidural anesthesia, the epidural needle is inserted from the back of the patient, through 3-5 cm blind insertion, then pushed into the narrow epidural space. If the needle was inserted too deep, dural puncture would happen and result in cerebral spinal fluid (CSF) leakage. The risk in conducting EA is even higher in obesity, pregnant, pediatric, post-spinal surgery, and for patients with unusual spinal column structure. We have developed an integrated high-frequency ultrasound needle transducer, which is able to provide guiding and positioning for EA insertion. The way to conduct this is to place the ultrasound needle transducer in the epidural needle, in order to provide positioning function in real-time. In this research, the ultrasound needle transducer has been optimized. The sensitivity of the needle transducer has increased up to 2 V. In another hand, use Field II to simulate a pair of coded signal, pass through matched filter to make pulse compressed. The SNR of the system is increased, and it is also been concert by test in a FPGA ultrasound pulser-receiver.
Lu, Chih-Wen, and 呂志文. "Design of Non-coherent Inner Convolutional Codes for Turbo-Coded OFDM System Over Frequency-Selective Fading Channels." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/96729848607977822608.
Повний текст джерела國立交通大學
電信工程研究所
101
In frequency-selective fading channels with unknown channel coefficients, channel estimation and equalization become infeasible. In this thesis, based on the cumulative distance functions of codes, we propose a simple method to select an inner convolutional code to co-work with an outer turbo code, which acts implicitly as a channel estimator and equalizer. Since the codeword length of the selected convolutional code is short, an exhaustive decoder based on the GLRT criterion can be implemented at the receiver end. Simulation results show that the concatenated coding system that use the convolutional codes of rate 1/2 performs well but may have rooms for improvement when the inner code rate increase to 2/3. In comparison with the tradition system that employs a least square (LS) estimator for the outer turbo code, our proposal can result in better performances and hence can be a good candidate design in a blind frequency-selective fading environment.
Oluwafemi, Ilesanmi Banjo. "Super-orthogonal space-time turbo coded OFDM systems." Thesis, 2012. http://hdl.handle.net/10413/8505.
Повний текст джерелаThesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.
Ojha, Anuj Raj. "Trellis coding on multi-amplitude continuous phase frequency shift keying /." 2007. http://proquest.umi.com/pqdweb?did=1453189151&sid=12&Fmt=2&clientId=10361&RQT=309&VName=PQD.
Повний текст джерела