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1
Dang, Xiaoyu. "Space-Time Shaped Offset QPSK." International Foundation for Telemetering, 2008. http://hdl.handle.net/10150/606190.
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ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, CaliforniaThis paper describes the use of orthogonal space-time block codes to overcome the performance and complexity difficulties associated with the use of Shaped Offset QPSK (SOQPSK) modulation, a ternary continuous phase modulation (CPM), in multiple-input multiple-output telemetry systems. The orthogonal space-time block code is applied to SOQPSK waveforms in the same way it would be applied to symbols. The procedure allows the receiver to orthogonalize the link. The main benefits of this orthogonalization are the easy realization of the transmit diversity for the offset-featured SQOSPK, and the removal of the noise correlation at the input to the space-time decoder and the elimination of I/Q interference when space time orthogonalization is applied to the symbol level.
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Machado, Hélder Filipe Pereira. "Implementação em FPGA de um Modem QPSK." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/15897.
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Mestrado em Engenharia Eletrónica e TelecomunicaçõesEsta dissertação insere-se num conjunto de trabalhos a decorrer no Instituto de Telecomunicações de Aveiro que tem como objetivo o desenvolvimento de um sistema de comunicação para um UAV. Neste sentido, apresenta a implementação e validação de um modem em banda base aberto e flexível implementado em FPGA, baseado em abordagem SDR, com possibilidade de integraçãoo no sistema de comunicação com o UAV. Ao longo desta dissertação implementou-se, utilizando o MATLAB, um modem de modulação adaptável, ao qual foram integrados algoritmos de sincronismo e de correção de fase. Desta forma, foi possível realizar uma análise ao modelo comportamental dos vários constituintes do modem abstraindose dos tempos de atraso do processamento ou da precisão da representação dos dados, e assim simplificar a sua implementação em hardware. Analisado o modelo comportamental do modem desenvolvido em MATLAB realizou-se a sua implementação em hardware para a modulação QPSK. A sua prototipagem foi realizada, com recurso à ferramenta computacional Vivado Design Suite 2014.2, utilizando o kit de desenvolvimento ZedBoard e o frontend AD-FMCOMMS1-EBZ. O correto funcionamento dos módulos implementados em hardware foi posteriormente avaliado através de uma interface entre o MATLAB e a Zed- Board, sendo que, os resultados obtidos no modelo em MATLAB serviram como termo de comparação. Através da utilização desta interface é possível validar parte do modem implementado em FPGA, mantendo o restante processamento a ser realizado em MATLAB, validando assim os módulos em FPGA de uma forma isolada.
This thesis is part of a series of work in progress at the Instituto de Telecomunicações of Aveiro which aims to develop a communication system for an UAV. Thereby, it presents the implementation and validation of a exible and open baseband modem implemented in FPGA, based on SDR approach, that can be integrated in the communication system with the UAV. Throughout this thesis was implemented an adaptive modulation modem and have been integrated timing recovery and phase correction algorithms, using the MATLAB. Thus, it is possible to perform an analysis of the behavioral of the several modem components abstracting the delay times of the processing or the precision of data representation, simplifying its hardware implementation. Analyzed the modem behavior developed in MATLAB was performed its hardware implementation for the QPSK modulation. Its prototype was done using the computational tool Vivado Design Suite 2014.2, the ZedBoard development kit and the frontend AD-FMCOMMS1-EBZ. The proper function of the modules implemented in hardware was evaluated by an interface between MATLAB and ZedBoard. This interface allows an individual validation of the implemented modem components in FPGA, keeping the remaining processing to be done in MATLAB and compared with the ones obtained in MATLAB.
3
Dang, Xiaoyu. "Offset QPSK in SISO and MIMO Environments." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1751.
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We demonstrate how the performance of offset quadrature phase-shift keying (OQPSK) and its variants of Feher-patented QPSK (FQPSK) and Shaped Offset QPSK (SOQPSK) (collectively known as the ARTM Tier-1 waveforms) in single input single output (SISO) system could change with the channel fading parameters. The bit error rate expression of offset QSPK and ATRM Tier-1 waveforms over the aeronautical telemetry multipath channel has been derived. Simulations show that for the case of a single multipath ray, the BER gets worse with increasing Γ for a fixed delay, and that the BER has a quasi-periodic property for fixed Γ and increasing τ. For the case of two multipath rays, the multipath component characterized by large amplitude and small delay is the main factor of the BER degradation, while the BER is not very sensitive to the change of multipath delay. Analysis of the average bit error probability shows that a relatively high error floor at approximately 10−2 occurs for |Γ1| ≥ 0.5. When offset quadrature phase-shift keying (OQPSK) is used in multiple input multiple output (MIMO) environment, orthogonal space-time block codes can be applied to waveforms to orthogonalize a space-time coded multiple-input, multiple output link. For offset QPSK, this technique has the advantage of eliminating the I/Q interference associated with simultaneous transmission of offset QPSK waveforms. In addition, orthogonalization presents uncorrelated noise samples to the space-time trellis decoder. As a consequence, a less complex space-time decoder (relative to what would be required without orthogonalization) can be used. It is demonstrated that a concatenated system based on an orthogonal space-time block code and a trellis code, optimized for single-input, single-output fading channel, outperforms a space-time trellis code for a 2x1 system. The space-time block code orthogonalizes the channel seen by the outer code and this simplifies the computations required for decoding. The advantages of orthogonalization are achieved at the expense of rate. In the examples presented, the codes were chosen to have roughly equivalent bit error rate performance and identical code rates: the complexity was compared.
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Weitzman, Jonathan M. "SELECTABLE PERMUTATION ENCODER/DECODER FOR A QPSK MODEM." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605817.
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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, NevadaAn artifact of QPSK modems is ambiguity of the recovered data. There are four variations of the output data for a given input data stream. All are equally probable. To resolve this ambiguity, the QPSK data streams can be differentially encoded before modulation and differentially decoded after demodulation. The encoder maps each input data pair to a phase angle change of the QPSK carrier. In the demodulator, the inverse is performed - each phase change of the input QPSK carrier is mapped to an output data pair. This paper discusses a very simple and unique differential encoder/decoder that handles all possible data pair/phase change permutations.
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Portelinha, Francisco Martins. "Uma tecnica de processamento digital para modem QPSK." [s.n.], 1994. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259768.
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Orientador: Rege Romeu ScarabucciDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica
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Resumo: Este trabalho apresenta uma nova técnica de processamento puramente digital para realizar as funções de modulação e demodulação QPSK (Quadrature Phase Shift Keying). Um protótipo experimental foi realizado e as medidas de desempenho mostraram resultados satisfatórios, compatíveis com desempenho obtidos através de outras implementações físicas
Abstract: Not informed.
Mestrado
Mestre em Engenharia Elétrica
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Ghate, Dilip B. "Implementation of a digital communication system using QPSK modulation." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA305334.
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Nelson, Tom. "ALAMOUTI SPACE-TIME CODING FOR QPSK WITH DELAY DIFFERENTIAL." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/607483.
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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, NevadaSpace-time coding (STC) for QPSK where the transmitted signals are received with the same delay is well known. This paper examines the case where the transmitted signals are received with a nonnegligible delay differential when the Alamouti 2x1 STC is used. Such a differential can be caused by a large spacing of the transmit antennas. In this paper, an expression for the received signal with a delay differential is derived and a decoding algorithm for that signal is developed. In addition, the performance of this new algorithm is compared to the standard Alamouti decoding algorithm for various delay differentials.
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Uzunoglu, Vasil, and Ann B. Maiorano. "PHASE CORRECTION AND PHASE CANCELLING NETWORKS IN QPSK MODEMS." International Foundation for Telemetering, 1985. http://hdl.handle.net/10150/615732.
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International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, NevadaAt bit rates lower than 100Mbit/s, the Synchronous Oscillator (SO) [1-4] has substantial tracking band combined with steep skirt selectivity to satisfy all the requirements of a carrier recovery network without the need for a phase correction network. At higher bit rates however, there is a need for a phase correction or phase cancelling network, if the BER variations with respect to hard wired case must be confined to less than 0.2dB with IF offsets of ±30kHz. At bit rates higher than 100Mbit/s, the multiply by four process in a QPSK modem deteriorates the signal-to-noise ratio by more than 15 dB (18dB at Eb/No = 6.4 dB) and the synchronization signal-to-noise ratio at the input to the SO drops below 0dB (!5dB at Eb/No = 6.4dB). This reduction in the signal-to-noise ratio reduces the tracking band of the SO which in turn increases the phase shift per unit frequency offset.
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Freitas, Alexandre Passos 1986. "Desenvolvimento de um modulador DP-QPSK em fotônica integrada." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259181.
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Orientadores: Hugo Enrique Hernandez Figueroa , Júlio César Rodrigues Fernandes de OliveiraDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: O crescente aumento da demanda de tráfego de dados dos sistemas de comunicação ópticos em conjunto com a busca da integração e miniaturização cada vez maior dos componentes impulsionaram a fotônica integrada em silício como uma das tecnologias promissoras para a evolução das novas gerações de dispositivos ópticos. Esta tecnologia, além de possuir suas características de um alto contraste de índice de refração, capacidade de modulação óptica através de controle de temperatura ou por densidade de portadores, se utiliza da infra-estrutura de fabricação para a indústria de microeletrônica já desenvolvida nas últimas décadas. Neste cenário, este trabalho propõe o desenvolvimento de um modulador de fase fabricado com a tecnologia de fotônica integrada em silício para o formato de modulação DP-QPSK e que opere na banda C de comunicação óptica. Análises de simulações e experimentais foram realizadas para a validação do fluxo de desenvolvimento do circuito e de cada componentes utilizado individualmente
Abstract: The increasing demand for data in optical communication systems with a constant search for reduction of device dimensions boosted silicon photonics as a candidate technology to the following optical device generations. Besides having high refractive index contrast, modulation capabilities through thermal or by carrier density control, this technology takes advantage of the microelectronic infra-structure developed in the last decades to fabricate small optical components with high reliability. In this scenario, this dissertation proposes the design of a phase modulator in silicon photonic technology. This modulator is able to operate at C-band and make the DP-QPSK modulation. Simulation and experiment analysis were made to validate the design flow for the optical circuit and for each single component
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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Portela, Thiago Ferreira. "Técnicas de recuperação de relógio para sistemas DP-QPSK." reponame:Repositório Institucional da UnB, 2012. http://repositorio.unb.br/handle/10482/13345.
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2012.Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2013-06-12T12:40:19Z No. of bitstreams: 1 2012_ThiagoFerreiraPortela.pdf: 1500626 bytes, checksum: 10f510c28cb5e25ff7f23f598a18d0a0 (MD5)
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Este trabalho propõe um novo método de estimação de erros de temporização para sistemas ópticos com multiplexação em polarização, detecção coerente e modulação de fase por chaveamento em quadratura (dual-polarization quadrature phase-shift keying - DP-QPSK). Em tais sistemas, a recuperação de relógio e a equalização são operações cruciais do processo de recuperação da informação transmitida e possuem uma relação de interdependência: a equalização depende da correta amostragem do sinal, enquanto a recuperação de relógio requer a pré-compensação das distorçõe lineares para obter desempenho satisfatório. O algoritmo proposto resolve esse problema por meio da cooperação entre equalização e recuperação de relógio, utilizando os coeficientes de um equalizador adaptativo para estimar o erro de temporização do sinal recebido. O desempenho do algoritmo proposto foi validado e comparado ao desempenho do algoritmo de Gardner utilizando dados experimentais gerados por um sistema óptico DP-QPSK, operando à taxa de 112 Gb/s. Os dados experimentais foram cedidos pela Ericsson-Alemanha e processados de modo on-line, utilizando o software de simulação Matlab. O algoritmo proposto conseguiu sincronizar o relógio em todos os casos ava- liados, inclusive nas situações em que o algoritmo de Gardner se mostrou incapaz. No entanto, apresentou uma leve penalidade em comparação ao mesmo sinal sem erro de temporização. Ademais, constatou-se que o per´ıodo de convergência da sincronização realizada pelo algoritmo está diretamente relacionado ao comprimento do equalizador. O algoritmo proposto se mostrou uma alternativa interessante para sistemas ópticos DP-QPSK. ______________________________________________________________________________ ABSTRACT
This work proposes a novel method of timing error estimation in polarization multi- plexed quadrature phase-shift keying (DP-QPSK) optical systems that employ coherent detection. In these systems, clock recovery and equalization are two crucial operations of the information recovery process that are interdependent: equalization depends on the correct signal sampling, whereas clock recovery requires a previous linear distorti- ons’ compensation for a satisfactory performance. The proposed algorithm solves this problem by collaboration between equalization and clock recovery processes, using the equalizer coefficients to estimate the received signal timing error. The performance of the proposed algorithm was validated and compared to the per- formance of the Gardner algorithm using experimental data, generated by DP-QPSK optical systems, transmitting at 112 Gb/s. These data were provided by Ericsson- Germany and processed offline, using Matlab simulation software. The proposed al- gorithm managed to synchronize the clock in all evaluated cases, including the cases where the Gardner algorithm failed. However, it presented a slight penalty comparing to the same signal without the timing error. Also, it was found that the synchroniza- tion convergence time is directly related to the equalizer length. Thus, the proposed algorithm is an interesting alternative for DP-QPSK optical systems.
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Dang, Xiaoyu. "Performance Analysis of FQPSK and SOQPSK in Aeronautical Telemetry Frequency Selective Multipath Channel." International Foundation for Telemetering, 2004. http://hdl.handle.net/10150/605801.
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International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, CaliforniaThe impact of frequency selective multipath fading on the bit error rate performance of ARTM Tier-1 waveforms (FQPSK and SOQPSK) is derived and analyzed. In the presence of a strong specular reflection with relative magnitude |Γ1|, the ARTM Tier-1 waveforms suffer a loss in performance of (1 - |Γ1)^(-4√(|Γ1|)) for |Γ1| < 0:5 and a relatively high error floor at approximately 10^(-2) for |Γ1| ≥ 0.5. The ARTM Tier-1 waveforms possess twice the spectral efficiency of PCM/FM, but exhibit a greater loss and higher error floors than PCM/FM for the same multipath conditions and signal-to-noise ratio.
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Meng, Huaiyu. "Towards integrated QPSK transceiver on zero-change CMOS foundry process." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/93779.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 127-136).
In recent years, the demand for Internet bandwidth increases while the unit price of bandwidth decreases. To keep up with the trend, more cost-eective optical telecommunication links are required. Due to the limited amount of optical fibers and wave- length range, increasing spectral eciency is a desirable approach. Advance modulation scheme, such as quadrature phase-shift keying (QPSK), is a possible solution. Another limitation is energy consumption. Power density within telecommunication data centers are regulated by law in consideration of ambient temperature and noise level. Therefore, optical transceivers with higher energy eciency is desired. Traditional transceivers use III-V chips for photonic components and CMOS chips for electronic circuits. Monolithic integration of photonic and electronic components helps removing energy consumption for inter-chip communication and hence increase overall energy eciency. In this thesis, a QPSK transceiver in zero-change CMOS process is proposed. Research is focused on three photonic components: 90 degree hybrids, poly-silicon photodetectors and QPSK modulators. Hybrids are used to mix QPSK-modulated signal and local oscillators with four equally-spaced phase delays. Multi-mode interferometers (MMI) are designed for this purpose. Best devices provides intensity imbalance around 1 dB and phase error around 10. For poly-silicon photodetectors, sub-bandgap defect states are used for electron-hole pair generation. A ring-resonant structure is used to enhance absorption and reduce footprint. Best devices have quantum eciency around 3.5% and dark current less than 60 nA under 25V reverse bias. The 3 dB frequency is around 1.2 GHz. Finally, double-coupled ring resonators with feed through waveguides are used for QPSK modulators. Carrier injection changes the resonance condition and provides phase shift. With the development of these devices, the path towards a monolithic QPSK transceiver in CMOS becomes clear.
by Huaiyu Meng.
S.M.
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Kotze, P. P. A. (Pieter Paul Adriaan). "Development of a QPSK demodulator for the Sunsat 1 groundstation." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51689.
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Thesis (MEng)--Stellenbosch University, 2000.ENGLISH ABSTRACT: The purpose of this thesis is the description of the development of a QPSK demodulator for the Sunsat 1 groundstation. A general overview of the functioning and requirements of a typical QPSK demodulator system is given. Several methods or algorithms for clock and carrier recovery are discussed. Specific attention is given to the QPSK demodulator chipset from Philips used for the implementation of the demodulator. The digital decoding logic used to serialize the parallel I and Q datastream is explained. Finally measurement techniques for performance evaluation of QPSK systems are investigated. As part of this the implementation loss of the developed QPSK demodulator is measured.
AFRIKAANSE OPSOMMING: Die doelwit van hierdie tesis is om die ontwikkeling van 'n QPSK demodulator vir die Sunsat 1 grondstasie te beskryf. 'n Algemene oorsig oor die funksionering en vereistes van 'n tipiese QPSK demodulator stelsel word gegee. Verskeie algoritmes en tegnieke vir klok en draersein herwinning word ondersoek en bespreek. Spesifieke verwysing word telkens gemaak na die QPSK demodulasie vlokkie paar van Philips gebruik vir die implementering van die demodulator. Die digitale dekodering logika benodig vir die datastroom verpakking word ondersoek en beskryf. Laastens word daar gekyk na meettegnieke en evaluasie van QPSK demodulasie stelsels se prestasie. As deel hiervan word die implementasie verlies van die ontwikkelde QPSK demodulator stelsel gemeet.
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Lee, Tong-Fu, Shih-Ho Wang, Chia-Liang Liu, and Liu Bao. "FQPSK-L: An Improved Constant Envelope Modulation Scheme for QPSK." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/609210.
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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaA new constant envelope modulation scheme and architecture for QPSK by cubic spline interpolation methods which increase spectral efficiency and power efficiency, named FQPSK-L, is presented. This modulation technique is an extension of the Feher Quadrature Shift Keying (FQPSK) patented technologies, see Ref [1]. Being a constant envelope modulation, FQPSK-L can operate with class C power amplifier without spectrum regrowth. We achieve a more compact spectrum with comparable bit error rate performance. For example, FQPSK-L is about 20% more spectral efficient than GMSK BTb=0.3 from 40 to 70 dB attenuation point. Moreover, FQPSK-L intrinsically has spikes at fc ± 0.5fb, fc ± 1.0fb, fc ± 1.5fb, ... which are useful for carrier recovery, symbol time recovery and fading compensation. In Rayleigh fading channel, FQPSK-L outperform GMSK BTb=0.3 by 0.8 dB. FQPSK-L is an excellent scheme for wireless and satellite communications which require high spectral and power efficiency.
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Eidenvall, Per, and Nils Gran. "High Level Ultra Low Power Transmitters for the MICS Standard." Thesis, Linköpings universitet, Elektroniska komponenter, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-62656.
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Today, medical implants such as cardiac pacemakers, neurostimulators, hearing aids anddrug delivery systems are increasinglymore important and frequently used in the health caresystem. This type of devices have historically used inductive coupling as communicationmedium. Newdemands on accessibility and increased performance in technology drives newresearch toward using radio communications. The FCCMICS radio standard are specificallydevoted for implantable devices.Basically all published research on transmitters in this area are using frequency shift keying(FSK) modulation. The purpose of this thesis is to explore the viability of using phase shiftkeying (PSK) modulation in ultra low power transmitters and suggest suitable architectures.
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James, Calvin L. "COMPLEX WAVEFORM GENERATION UTILIZING FIELD PROGRAMMABLE GATE ARRAYS." International Foundation for Telemetering, 1997. http://hdl.handle.net/10150/609692.
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International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, NevadaThe basic building blocks for implementing complex waveform generators using a look-up table approach are random access memory (RAM) and read only memory (ROM) devices. Due to technological advancements in field programmable gate array (FPGA) development, these devices have the ability to allocate large amounts of memory elements within the same structure. The self containment property makes the FPGA a suitable topology for complex waveform generation applications. In addition, this self containment property significantly reduces implementation costs by reducing the number of external components required to support many applications. This paper examines the use of FPGA’s in various complex waveform generation applications. In particular, a discussion will ensue examining possible mappings of the time domain response of the complex waveform into memory elements of the FPGA. The analyses and examples contained in the sequel are from existing waveform generation applications, developed for Gauissian Minimum Shift Keying (GMSK) and Unbalanced Quadriphase Shift Keying (UQPSK) modulation formats.
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Ramantanis, Petros. "Contribution to the analysis of optical transmission systems using QPSK modulation." Phd thesis, Institut National des Télécommunications, 2011. http://tel.archives-ouvertes.fr/tel-00765380.
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The constant demand for capacity increase, together with the foreseen saturation of the single-mode optical fiber, paved the way to technological breakthroughs that have completely changed the landscape of fiber-optic telecommunications. The most important advance was, undeniably, the practical implementation of a coherent detection with the help of high-speed electronics. This has, first, enabled the use of advanced modulation formats that allowed for a more efficient use of the fiber bandwidth, compared to the classical On-Off Keying, while adapted algorithms could not be used in order to mitigate the optical signal degradation. This thesis began a little after the advent of coherent detection and its main objective was to revisit the propagation effects in optical transmission systems using "Quadrature phase shift keying" (QPSK) modulation in the context of terrestrial systems, i.e. for transmission distances of up to about 2000 km. The manuscript is divided into two parts. The first part is dedicated to a study on the data sequences that need to be used in numerical simulations, when advanced modulation is involved. Fiber propagation, and in particular the interplay between chromatic dispersion and nonlinearities, usually introduce a nonlinear inter-symbol interference (ISI) to the transmitted signal. Since this ISI depends on the actual transmitted data pattern, it is obvious that the choice of the sequence used in our numerical simulations will have a direct influence on the estimated channel quality. Since, an infinite length, random sequence is impractical; we very commonly use pseudorandom" (PR) sequences, i.e. finite-length, deterministic sequences with balanced pattern statistics that seem to be random. In the first part we describe the method of generating M-level (with M>2) pseudorandom sequences and we detail their properties. In addition, we propose numerical tools to characterize the non-pseudorandom sequences that we use in numerical simulations, or we are sometimes forced to use in laboratory experiments. Finally, we present results of numerical simulations that quantify the necessity to use PR sequences as a function of our system parameters. After having established the "fairest possible" finite sequences, in the second part of the manuscript, we focus on the study of the nonlinear propagation, in the context of a transmission system using QPSK modulation and assuming a variable dispersion management and fiber type. Specifically, we numerically study the signal statistics due to the interplay of chromatic dispersion and nonlinear effects, neglecting all polarization or multi-wavelength effects and the amplifier noise. In this context, we were first interested in determining whether some empirical laws developed for OOK systems, can be also used in the case of QPSK modulation, such as the criterion of cumulative nonlinear phase (ΦNL) or laws that allow for a quick optimization of the dispersion management. Next we reveal the importance of a global phase rotation added to the initial signal constellation, as a parameter that can provide interesting information for the post-optimization of our system. We also discuss the fact that the constellation shape critically depends on the applied dispersion management, while there are generally 3 types of constellations, concerning the complex signal statistics: (1) the phase variance is higher than the amplitude variance (2) the amplitude variance is higher than the phase variance and (3) the received signal constellation resembles to a constellation of a signal under the influence of just an Additive White Gaussian Noise. Finally, we provide a phenomenological explanation of the constellations shapes revealing the fact that different data sub-sequences suffer from a different kind of signal degradation, while we also use this information to define a parameter that quantifies the potential benefit from a MAP (Maximum A Posteriori probability) correction algorithm
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Ramantanis, Petros. "Contribution to the analysis of optical transmission systems using QPSK modulation." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2011. http://www.theses.fr/2011TELE0020.
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La demande constante de capacité et la saturation prévue de la fibre monomode ont conduit récemment à des avances technologiques qui ont complètement changé le paysage des télécommunications à fibre optique. Le progrès le plus important était la mise en œuvre d'une détection cohérente à l'aide d'électronique rapide. Cela a permis pas seulement l'utilisation de formats de modulation qui promettent une utilisation plus efficace de la bande passante, mais aussi l’utilisation des algorithmes adaptés pour combattre la dégradation du signal optique due à la propagation. Cette thèse a commencé un peu après le début de cette « ère du cohérent » et son principal objectif était de revoir les effets physiques de la propagation dans des systèmes de transmission terrestres, utilisant le format de modulation QPSK (Quadrature Phase Shift Keying). Le manuscrit est divisé en deux parties. La première partie est consacrée à une étude sur les séquences des données qui doivent être utilisés dans les simulations numériques, lorsqu’un format de modulation avancée est impliqué. La propagation, et en particulier l'interaction entre la dispersion chromatique et les non-linéarités, introduisent une interférence inter-symbole (ISI). Vu que cet ISI dépend de l’enchainement des données transmises, il est évident que le choix de la séquence a une influence sur la qualité estimée du canal. Etant donné que des séquences aléatoires infinies ne sont pas pratiquement réalisables, nous utilisons souvent des séquences « pseudo-aléatoires » (PR), i.e. des séquences déterministes de longueur finie, avec des statistiques équilibrés, qui semblent être aléatoires. Dans la première partie, nous décrivons la méthode de génération de séquences PR avec M. niveaux (M> 2) et nous détaillons leurs propriétés. En outre, nous proposons des outils numériques pour caractériser les séquences non pseudo-aléatoires qu’on utilise souvent dans des simulations, ou parfois aussi dans des expériences au laboratoire. Enfin, nous présentons les résultats de simulations qui permettent de quantifier la nécessité d'utiliser des séquences PR en fonction des paramètres du système. Après avoir établi les séquences finies "les plus adaptées", dans la seconde partie du manuscrit, nous nous concentrons sur l'étude de la propagation, dans le contexte d'un système de transmission QPSK et en supposant une gestion de dispersion et un type de fibre variables. Plus précisément, nous étudions numériquement les statistiques de signaux dégradés dus à l'interaction de la dispersion chromatique avec les effets non linéaires, en négligeant tout effet de polarisation ou inter-canaux, aussi que le bruit des amplificateurs. Dans ce contexte, nous étions intéressés à déterminer si certaines lois empiriques développées pour les systèmes OOK, sont valable dans le cas d'une modulation QPSK, tels que le critère de la phase non-linéaire cumulée (ΦNL) ou des lois qui permettent une optimisation de la gestion de dispersion. Ensuite, nous révélons l'importance de la rotation de la constellation du signal initial, comme un paramètre qui peut fournir des informations pour la post-optimisation de notre système. Nous discutons également autour du fait que la forme de la constellation dépend de la gestion de dispersion et concernant les constellations nous concluons qu'il y en a généralement 3 types, avec: (1) une variance de phase supérieure à la variance d'amplitude (2) une variance d'amplitude supérieure à la variance de phase et (3) avec le signal ayant une constellation qui ressemble à la constellation d’un signal sous l'influence d'un bruit blanc gaussien additif. Enfin, nous fournissons une explication phénoménologique des formes des constellations révélant le fait que des sous-séquences différentes conduisent à un « type » différent de dégradation et nous utilisons ces informations pour définir un paramètre qui quantifie le bénéfice potentiel d'un algorithme de correction du type MAP(Maximum A Posteriori Probability)The constant demand for capacity increase, together with the foreseen saturation of the single-mode optical fiber, paved the way to technological breakthroughs that have completely changed the landscape of fiber-optic telecommunications. The most important advance was, undeniably, the practical implementation of a coherent detection with the help of high-speed electronics. This has, first, enabled the use of advanced modulation formats that allowed for a more efficient use of the fiber bandwidth, compared to the classical On-Off Keying, while adapted algorithms could not be used in order to mitigate the optical signal degradation. This thesis began a little after the advent of coherent detection and its main objective was to revisit the propagation effects in optical transmission systems using "Quadrature phase shift keying" (QPSK) modulation in the context of terrestrial systems, i.e. for transmission distances of up to about 2000 km. The manuscript is divided into two parts. The first part is dedicated to a study on the data sequences that need to be used in numerical simulations, when advanced modulation is involved. Fiber propagation, and in particular the interplay between chromatic dispersion and nonlinearities, usually introduce a nonlinear inter-symbol interference (ISI) to the transmitted signal. Since this ISI depends on the actual transmitted data pattern, it is obvious that the choice of the sequence used in our numerical simulations will have a direct influence on the estimated channel quality. Since, an infinite length, random sequence is impractical; we very commonly use pseudorandom" (PR) sequences, i.e. finite-length, deterministic sequences with balanced pattern statistics that seem to be random. In the first part we describe the method of generating M-level (with M>2) pseudorandom sequences and we detail their properties. In addition, we propose numerical tools to characterize the non-pseudorandom sequences that we use in numerical simulations, or we are sometimes forced to use in laboratory experiments. Finally, we present results of numerical simulations that quantify the necessity to use PR sequences as a function of our system parameters. After having established the “fairest possible” finite sequences, in the second part of the manuscript, we focus on the study of the nonlinear propagation, in the context of a transmission system using QPSK modulation and assuming a variable dispersion management and fiber type. Specifically, we numerically study the signal statistics due to the interplay of chromatic dispersion and nonlinear effects, neglecting all polarization or multi-wavelength effects and the amplifier noise. In this context, we were first interested in determining whether some empirical laws developed for OOK systems, can be also used in the case of QPSK modulation, such as the criterion of cumulative nonlinear phase (ΦNL) or laws that allow for a quick optimization of the dispersion management. Next we reveal the importance of a global phase rotation added to the initial signal constellation, as a parameter that can provide interesting information for the post-optimization of our system. We also discuss the fact that the constellation shape critically depends on the applied dispersion management, while there are generally 3 types of constellations, concerning the complex signal statistics: (1) the phase variance is higher than the amplitude variance (2) the amplitude variance is higher than the phase variance and (3) the received signal constellation resembles to a constellation of a signal under the influence of just an Additive White Gaussian Noise. Finally, we provide a phenomenological explanation of the constellations shapes revealing the fact that different data sub-sequences suffer from a different kind of signal degradation, while we also use this information to define a parameter that quantifies the potential benefit from a MAP (Maximum A Posteriori probability) correction algorithm
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Fang, Ting-Kuo Sun Wei-Long. "Dataset simulation and RF path modeling of a QPSK radio communication system /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Sep%5FFang.pdf.
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Lidon, Maria Sol. "Digital Pre-compensation of Chromatic Dispersion in QPSK high speed telecom systems." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-51039.
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Chromatic dispersion (CD) is one of the most significant impairments in optical fiber communication systems. Since expensive and complex optical components are required to mitigate CD in the optical domain high-speed digital signal processing techniques are becoming an alternative to compensate electronically both non-linear and linear optical fiber degradations in the transmitter or receiver. This thesis investigates a new electronic dispersion compensation technique based on signal predistortion using an electro-optic modulator driven by signals previously filtered by a linear Finite Impulse Response filter. Moreover, since transmitter and local oscillator lasers phase noise has usually been assessedindependently without regard to the effect of chromatic dispersion on the phase noise in the system performance, a comparative study between pre- and postcompensation of chromatic dispersion influence on equalization enhanced phase noise (EEPN) in coherent multilevel systems is carried out. For that purpose, carrier phase estimation is implemented by a one-tap normalized least-meansquare filter. Simulations of chromatic dispersion equalization in the transmitter demonstrate that a 56-Gbit/s QPSK coherent system is able to compensate large amounts of fiber chromatic dispersion using a predistorting linear finite impulse response filter. Concerning impact of chromatic dispersion compensation on equalization enhanced phase noise, simulation results show for postcompensation scheme the local oscillator phase noise limits the EEPN influence in the system. However, when the CD equalization is performed in the transmitter, the transmitter laser phase noise is the limiting factor that determines the EEPN effect in the transmission system. Most of those constraints may be mitigated by performing CD compensation in optical domain in such a way that the EEPN influence could be neglected.
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Biyoghe, Joel S. "Design and implementation of a high data rate QPSK demodulator for nanosatellites." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2744.
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Thesis (Master of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, 2017.This dissertation presents the development of a quadrature phase shift keying (QPSK) demodulator for nanosatellites that complies with both the limited resources associated with nanosatellites as well as the flexibility and configurability required for a software defined radio (SDR) platform. This research project is a component of a bigger project, which is to develop a high-speed receiver for nanosatellites, and aims to provide a practical solution to the need for communication technologies that support emerging nanosatellite applications, such as Earth observation and communications. The development of the QPSK demodulator follows an all-digital implementation approach. The main reason for selecting this approach is to have a system that is flexible and reconfigurable to comply with the SDR requirements. Another reason for selecting this approach is to comply with the low noise system, low power consumption as well as the small size and weight requirements associated with nanosatellites. The QPSK demodulator is implemented on an IGLOO2 Field Programmable Gate Array (FPGA), due to its robustness to radiation and high-speed capability. Initially, the techniques used to design each subsystem of the QPSK demodulator are selected. Then, algorithms to digitally implement the designed subsystems are produced. Thereafter, the code for the digital QPSK demodulator is written and verified in Matlab first. The simulation of the Matlab-based QPSK demodulator performs satisfactorily. Subsequently, the code to implement the QPSK demodulator on an FPGA (IGLOO2) has been written in Libero, using VHSIC Hardware Description Language (VHDL). The resulting FPGA-based QPSK demodulator has been emulated in Libero (an integration and development environment (IDE) for Microsemi FPGAs) using a test-bench as well as other analysis tools. The test-bench results are visualized using Modelsim. The results show that the demodulator can support data rates up to 13.25 Mbps if 16 samples-per-symbols are used, and up to 26.5 Mbps if 8 samples-per-symbols are used. It also has a very good bit-error-rate performance, which is simulated to be within a factor of 5 of the theoretical limit of QPSK modulation. Finally, the demodulator consumes less than 15 mW at the maximum operating speed. and has been coded to mitigate the effects of space radiation and noise contriution by the demodulator itself.
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Malan, Jacques de Villiers. "Microwave data transmission by means of an optimal bandwidth multichannel QPSK system." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50022.
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Thesis (MScEng)--Stellenbosch University, 2004.Full text to be digitised and attached to bibliographic record.
ENGLISH ABSTRACT: The increase in the complexity and functionality of new satellites leads to a growing demand for a digital communication system operating at a much higher bit rate than before. The main purpose of this thesis is to address precisely this problem. The theory as well as a practical high speed system are custom-developed. The goal of this thesis is not to reinvent the wheel, but to use off-the-shelf products as far as possible. This system demonstrates that a very high data rate is not out of reach for a developer with limited funds. The secondary goal is to understand the operation of this communication system. The emphasis is on the inaccuracies in the system. A design tool is created to act as a vehicle for understanding the influence of a single variable on the performance of the entire system.
AFRIKAANSE OPSOMMING: Die toename in die kompleksiteit en funksionaliteit van nuwe satelliete lei tot die groeiende behoefte aan 'n digitale kommunikasiestelsel wat teen "n heelwat hoër bis spoed funksioneer. Die hoofdoel van hierdie tesis is om juis hierdie probleem aan te spreek. Die teorie en 'n praktiese hoëspoed stelsel is ontwikkel. Die doel van die tesis is nie om die wiel te herontdek nie maar om sover moontlik bestaande produkte in die ontwerp van die stelsel te gebruik. Die stelsel demonstreer dat 'n hoëspoed datatempo nie buite die bereik van 'n ontwikkelaar met beperkte fondse is nie. 'n Verdere doelwit is om die funksionering van die kommunikasie stelsel te begryp. Klem is gelê op die onakkuraathede in die kommunikasiestelsel. Ontwikkeling sagteware is geskep as "n metode om die invloed van "n enkele veranderlike op die werkverrigting van die stelsel as geheel te begryp.
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Ferreira, Hugo Borges. "Algoritmos de recuperação de fase para sistemas ópticos com modulação DP-QPSK." reponame:Repositório Institucional da UnB, 2011. http://repositorio.unb.br/handle/10482/10417.
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, 2011.Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2012-05-07T14:17:30Z No. of bitstreams: 1 2011_HugoBorgesFerreira.pdf: 1904412 bytes, checksum: 5be7cb37c9fdb70605abcdd95646a191 (MD5)
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O crescimento na demanda por tráfego Ethernet tem motivado o desenvolvimento de novos sistemas de transporte de dados a altas taxas e longas distâncias. Um novo esquema de transmissão óptica aparece como solução, permitindo taxas de transmissão superiores a 100 Gb/s por canal óptico. Esse esquema utiliza a modulação QPSK e a multiplexação de sinais em polarizações ortogonais (dual polarization QPSK - DP-QPSK), então, um receptor coerente se faz necessário. Nesses sistemas aliam-se processamento digital de sinais aos detectores coerentes para a compensaçãao de distorções ocorridas na transmissão e recepção. A recuperação de fase é um tópico relevante no projeto de receptores coerentes e várias técnicas podem ser aplicadas. Analisaram-se três técnicas de recuperação de fase, as clássicas Viterbi & Viterbi (V&V) e algoritmo direcionado a decisão (DD), e uma técnica computacionalmente eficiente, chamada aqui de hardware-efficient. Aliado à recuperação de fase, um algoritmo de recuperação de portadora, responsável por estimar diferen¸cas entre a frequência dos lasers transmissor e receptor, também foi estudado. Nas simulações, concluiu-se que a técnica de recuperação de portadora avaliada foi capaz de recuperar desvios de at´e 3, 125 GHz para um sistema DP-QPSK a 100 Gb/s com lasers de largura de linha de 1 MHz, sem penalidade significativa. As técnicas de recuperação de fase V&V e DD com filtro de máxima verossimilhan¸ca (maximum-likelihood - ML) (5 coeficientes) mostraram penalidades inferiores a 1 dB para o mesmo sistema, e inferiores a 0, 5 dB com filtros mais longos (> 10 coeficientes). O algoritmo hardware-efficient mostrou boa aproximação ao desempenho do V&V para um filtro com 5 coeficientes. Simularam-se ainda os algoritmos V&V e DD com filtros planos e filtros complexos não lineares (nonlinear complex filter - NCF) para comparação de resultados. Dados obtidos em um experimento com modulação DP-QPSK à taxa de 112 Gb/s também foram processados. Utilizaram-se técnicas de normalização, equalização e demultiplexação na recuperação do sinal, e os algoritmos de recuperação de fase e portadora foram testados. Uma técnica de estimação de SNR a partir do sinal ruidoso foi empregada, e o impacto sistêmico foi investigado. Mostrou-se que erros de estimação de −6 dB a 6 dB podem levar a até 1 dB de penalidade em um sistema DP-QPSK a 40 Gb/s. Para sistemas a 100 Gb/s, erros de estimação não levaram a penalidades significativas. O desempenho alcançado com o sistema experimental foi compatível ao simulado, validando o modelo teórico utilizado. _____________________________________________________________________________ ABSTRACT
The increasing demand for Ethernet traffic has motivated the development of new long-haul and high transmission rates optical systems. A new scheme for optical transmission appeared as a solution, allowing transmission rates higher than 100 Gb/s per optical channel. This scheme uses QPSK modulation and dual polarization multiplexing (DP-QPSK), therefore, a coherent receptor is needed. These systems combine digital signal processing techniques with the coherent detector, thus, compensating for distortions generated in transmission and detection. Phase recovery is an important subject in coherent receivers’ development and several techniques may be applied. We analyzed three phase recovery algorithms, the classical Viterbi & Viterbi (V&V) and decision directed (DD), and a hardware- efficient algorithm. A carrier recovery algorithm was also studied. This technique estimates frequency mismatches between transmitter and receiver lasers, whilst the phase recovery estimates the phase noise affecting the system. In our simulations, we concluded that the carrier recovery technique was able to compensating for a mismatch of up to 3, 125 GHz in a 100 Gb/s DP-QPSK system with 1 MHz lasers linewidth without noteworthy penalty. The V&V and DD recovery algorithms with maximum-likelihood (ML) filters (5 taps) exhibited less than 1 dB SNR penalty to this system, and less than 0, 5 dB for longer filters (> 10 taps). The hardware-efficient algorithm showed to be a good approximation of the V&V for a 5 taps filter. We also simulated the V&V and DD algorithms with flat filters and nonlinear complex filters (NCF) for comparison. We have also processed data from an optical 112 Gb/s DP-QPSK experimental system. We used normalization, equalization and demultiplexing techniques for the signal recovery and tested the carrier recovery algorithms. An estimation scheme for the SNR was used, and the systemic impact was analyzed. We observed that estimation errors from −6 dB to 6 dB may lead to up to 1 dB SNR penalty for a 40 Gb/s DP-QPSK system. For a 100 Gb/s system, estimation errors have not caused noteworthy SNR penalty. The experimental system performance was compatible with the simulated system, thus, validating our theoretical model.
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Wang, Xiaoyu Carleton University Dissertation Engineering Systems and Computer. "System performance analysis with pi/4-QPSK in an indoor wireless environment." Ottawa, 1994.
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Sawada, Manabu, Masaaki Katayama, and Akira Ogawa. "Effect of Nonlinear Amplifiers of Transmitters in the CDMA System Using Offset-QPSK." IEICE, 1993. http://hdl.handle.net/2237/7199.
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Pivato, Neto Luiz Affonso. "Impacto de imperfeições do front-end óptico no desempenho de sistemas dp-qpsk." reponame:Repositório Institucional da UnB, 2011. http://repositorio.unb.br/handle/10482/9746.
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, 2011.Submitted by Shayane Marques Zica (marquacizh@uol.com.br) on 2011-10-19T20:03:34Z No. of bitstreams: 1 2011_LuizAffonsoPivatoNeto.pdf: 2206003 bytes, checksum: bc7ffeddb628d49558d4d74c6d54dd47 (MD5)
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Para lidar com o aumento no tráfego de dados e com a incessante demanda por maisaltas taxas de transmissão, diversas arquiteturas de transceptores ópticos e técnicas deprocessamento de sinais, que possibilitem uma maior eficiência espectral, vêm recebendogrande atenção por parte dos pesquisadores ligados `as comunicações ópticas. Asarquiteturas mais promissoras para o alcance de taxas de transmissão líquidas de 100Gbit/s por canal combinam a detecção coerente com a multiplexação de polarização ecom formatos mais avançados de modulação, como o QPSK com codificação diferencial.A detecção coerente possibilita a compensação, no receptor, de efeitos lineares comoa dispersão cromática e a dispersão dos modos de polarização, além de favorecer amultiplexação de polarização. No entanto, a detecção coerente e os formatos avançadosde modulação introduzem a necessidade de se lidar com a recuperação de fase e compossíveis imperfeições nos componentes ópticos do transmissor e do receptor, o quepode ser feito por meio de técnicas de processamento digital de sinais.Nesse trabalho, foi estudado o impacto causado por imperfeições em componentesdo front-end óptico do receptor, as quais levam ao desbalanceamento de quadratura(quadrature imbalance - QI) e `a adição de componentes de ruído. Também, foramestudadas t´ecnicas utilizadas para a compensação do QI. Por meio de simulações emMATLAB R, foram comparados os desempenhos de quatro esquemas de compensaçãodo QI: o método de Gram-Schmidt e o método de ajuste por elipses, aplicados, cadaqual, antes e depois da demultiplexação de polarização. Foi analisado, ainda, o desempenho conjunto entre essas técnicas de compensação do QI e dois algoritmos utilizadosna demultiplexação de polarização: o algoritmo do módulo constante e o algoritmo damédia quadrática mínima.´É mostrado que, em uma pequena escala de imperfeições no front-end, os quatro esquemascompensam eficientemente o QI inserido. No entanto, quando o QI aumenta,a utilização do método de Gram-Schmidt antes da demultiplexação de polarização,considerando as condições propostas, exibe a menor penalidade para o sistema. Ademais,o desempenho dos algoritmos de demultiplexação de polarização investigados emconjunto com as técnicas de compensação do QI foi bastante similar. _______________________________________________________________________________ ABSTRACT
In order to deal with the increasing data traffic and the incessant demand for higher transmission rates, several optical transceiver architectures and signal processing techniques, enabling a higher spectral efficiency, have been receiving considerable attention from researchers connected to optical communications. Most promising architectures targeting net data rates of 100 Gbit/s per channel combine coherent detection and polarization multiplexing with advanced modulation techniques, such as differential encoding QPSK. The coherent detection provides compensation of linear effects, such as chromatic dispersion and polarization mode dispersion, in addition to favoring polarization multiplexing. However, coherent detection and advanced modulation techniques introduce the need to deal with phase recovery and possible imperfections in the transmitter and receiver optical components, which can be accomplished by digital signal processing techniques. This thesis investigates the impact caused by imperfections in components of the receiver optical front-end, leading to quadrature imbalance (QI) and adding noise terms. Techniques used to compensate for QI were also studied. Through MATLAB R simulations, the performances of four QI compensation schemes were compared: the Gram-Schmidt method and the ellipse fitting method, each one applied before and after polarization demultiplexing. In addition, the joint performance of these QI compensation techniques and two polarization demultiplexing algorithms – the constant modulus algorithm and the least mean square algorithm – was analyzed. It is shown that, in a small scale of front-end imperfections, the four schemes efficiently compensate for the inserted QI. However, when this scale increases, using theGram-Schmidt method before polarization demultiplexing, considering the proposed conditions, exhibits the lowest penalty for the system. Moreover, the performance of the investigated polarization demultiplexing algorithms was quite similar.
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Sun, Wei-Long. "Data set simulation and RF path modeling of a QPSK radio communication system." Thesis, Monterey, California. Naval Postgraduate School, 2005. http://hdl.handle.net/10945/2112.
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This project simulates QPSK modulation signals and uses a laboratory environment to create deteriorating effects of real-world high frequency (HF) transmissions that may modify the ideal QPSK waveform. These modifications may be identifiable in order to "fingerprint" the source of the modifications. To simulate the transmission path in the real world a signal generator is used to create the QPSK I/Q signal at the HF operating frequencies and a digital sampling oscilloscope acts as a receiver and records the data for analysis. A computer with MATLAB Instrument-control Toolbox is used to generate a random-input data stream as an input to the signal generator, which modulates the RF signal. The RF signal was chosen to be at HF (5-15 MHz) and the QPSK modulation was at 9600 baud. The deterioration effects of a real-world transmitter site were chosen to be associated with the output amplifier linearity and with the transmission line condition between the transmitter and antenna.
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Semmar, Assia. "L'effet du profil de délai sur la performance des systèmes QPSK à large bande." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0022/NQ52258.pdf.
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Rosmansyah, Yusep. "Soft-demodulation of QPSK and 16-QAM for turbo coded WCDMA mobile communication systems." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/792192/.
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Dang, Xiaoyu. "A Bit Error Rate Analysis of Offset QPSK over the Aeronautical Telemetry Multipath Channel." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605567.
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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, NevadaThe impact of multipath fading parameters on the probability of error for Offset QPSK (OQPSK) is derived. The multipath fading channel is modeled using the aeronautical telemetry channel model [1-2]. Expressions for the probability of bit error are derived that are a function of the multipath model parameters. The expressions are shown to agree with computer simulations and show that a strong multipath reflection with a short delay causes much more degradation than a weak multipath reflection with a long delay.
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Hill, Terrance J. "AN ENHANCED, CONSTANT ENVELOPE, INTEROPERABLE SHAPED OFFSET QPSK (SOQPSK) WAVEFORM FOR IMPROVED SPECTRAL EFFICIENCY." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606498.
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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, CaliforniaShaped BPSK (SBPSK) and Shaped Offset QPSK (SOQPSK), as defined in various MIL standards, are widely employed on SATCOM links because they offer an attractive combination of good spectral efficiency, constant envelope characteristics, and interoperability with legacy equipments. More recently, numerous terrestrial applications of OQPSK and similar waveforms (Feher-patented FQPSK) have been proposed. The present paper describes a simple non-proprietary modification of the MIL-STD SOQPSK waveform which offers spectral containment and detection efficiency comparable to or better than FQPSK-B (Revision A1), while preserving a constant envelope characteristic and backward compatibility with existing equipment.
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Kadlček, Václav. "Modelování silové sítě pro datovou komunikaci." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218194.
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Thesis deals with problems PLC (Power Line Communication) communication. It is aimed at drawing up a suitable model for testing power network PLC communication. The reader is aware of at the beginning of work with the basic principles of PLC systems, distribution and use in communication networks. Another part of the work deals with different types of interference, which occur in power networks and ways to defend against such interference. For example, an appropriate choice of modulation and coding relevant. As a source of interference in the proposed model is used AWGN channel (Additive White Gaussian Noise). Conclusion of work is dedicated to design and build a model for PLC communication. There are three models designed with different OFDM technology. Models therefore vary between different levels of key mapping in OFDM (QPSK, 16-QAM, 64-QAM). It made a detailed description of a set of blocks that were used to build models. The behavior and functionality of the proposed models for broadband PLC communication was verified in the simulation program Matlab Simulink. Finally, it is shown the comparison and evaluation of results of each modulation.
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Hischke, Sven. "New receivers for differentially encoded Offset-QPSK : investigation in differential demodulation and per-survivor-processing algorithms." Thesis, City University London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310449.
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Rajyalakshmi, P. S., and R. K. Rajangam. "Data Handling System for IRS." International Foundation for Telemetering, 1987. http://hdl.handle.net/10150/615329.
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International Telemetering Conference Proceedings / October 26-29, 1987 / Town and Country Hotel, San Diego, CaliforniaThe three axis stabilized Indian Remote Sensing Satellite will image the earth from a 904 Km polar - sun synchronous orbit. The payload is a set of CCD cameras which collect data in four bands visible and near infra-red region. This payload data from two cameras, each at 10.4 megabits per sec is transmitted in a balanced QPSK in X Band. The payload data before transmission is formatted by adopting Major and Minor frame synchronizing codes. The formatted two streams of data are differentially encoded to take care of 4-phase ambiguity due to QPSK transmission. This paper describes the design and development aspects related to such a Data Handling System. It also highlights the environmental qualification tests that were carried out to meet the requirement of three years operational life of the satellite.
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Serbay, Murat. "Multilevel modulation formats for optical communication systems based on direct detection." Aachen Shaker, 2008. http://d-nb.info/991204263/04.
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Rozental, Valery Nobl. "Técnicas para redução de singularidades em receptores ópticos dp-qpsk que utilizam o algoritmo do módulo constante." reponame:Repositório Institucional da UnB, 2011. http://repositorio.unb.br/handle/10482/9488.
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, 2011.Submitted by Shayane Marques Zica (marquacizh@uol.com.br) on 2011-10-10T20:40:43Z No. of bitstreams: 1 2011_ValeryNoblRozental.PDF: 9912457 bytes, checksum: c5116694d395382279d3ccfa0baa22df (MD5)
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Este trabalho investiga de forma experimental o desempenho de algumas técnicas para evitar singularidades em receptores ópticos de sistemas DP-QPSK que operam na taxa de transmissão de 112 Gb/s, e cujos equalizadores utilizam o algoritmo do módulo constante (CMA) para a desconvolução e a separação de fontes. O termo “singularidade” se refere `a situação na qual ambas as saídas do equalizador convergem para o mesmo sinal de entrada. Os dados experimentais são obtidos usando um arranjo de transmissão que emula mudanças arbitrárias de polarização, ruído óptico, dispersão cromática e a dispersão dos modos de polarização de primeira ordem. A influência destes efeitos na ocorrência de singularidades é analisada individualmente. Em particular, são comparados os seguintes algoritmos: • CMA padrão; • CMA com restrição; • CMA de dois estágios; • CMA para usuários múltiplos (MU-CMA). É demonstrado que todos os algoritmos reduzem o número de singularidades de forma eficiente, melhorando, assim, as propriedades de convergência do equalizador. No entanto, sob certas condições, os algoritmos MU-CMA e CMA com restrição – ambos utilizados para inicialização do sistema – apresentaram melhor desempenho em comparação com CMA de dois estágios, que não distingue entre as fases de inicialização e de operação do sistema. `A luz dos resultados, considerando a sua baixa complexidade computacional, o CMA com restrição é recomendado para uso em sistemas práticos. _______________________________________________________________________________ ABSTRACT
This work experimentally investigates the performance of several techniques for singularity avoidance in optical receivers of dual-polarization quadrature phase shift keying (DP-QPSK) systems operating at the transmission rate of 112 Gb/s, and whose equalizers use the Constant Modulus Algorithm (CMA) for deconvolution and source separation. The term “singularity” refers to the condition where both equalizer outputs converge to the same input signal. Experimental data is acquired using a transmission setup that emulates arbitrary polarization changes, optical noise, chromatic dispersion (CD) and first-order polarization mode dispersion (PMD). The influence of these effects on the singularity occurrence is individually analyzed. Specifically, the following algorithms are compared: • Standard CMA; • Constrained CMA; • Two-Stage CMA; • Multi-User (MU) CMA. It is shown that all algorithms effectively mitigate singularities, thus improving equalizer convergence properties. However, under certain conditions, the Multi-User and Constrained CMA algorithms – both used for system startup – outperformed the Two-Stage CMA, which does not distinguish between the system startup and operation phases. In light of the results, considering also its low computational complexity, the Constrained CMA is recommended to be used in practical systems.
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Srivastava, Amit. "Design of Ultra Low Power Transmitter for Wireless medical Application." Thesis, Linköping University, Electronic Devices, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-18408.
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Significant advanced development in the field of communication has led many designers and healthcare professionals to look towards wireless communication for the treatment of dreadful diseases. Implant medical device offers many benefits, but design of implantable device at very low power combines with high data rate is still a challenge. However, this device does not rely on external source of power. So, it is important to conserve every joule of energy to maximize the lifetime of a device. Choice of modulation technique, frequency band and data rate can be analyzed to maximize battery life.
In this thesis work, system level design of FSK and QPSK transmitter is presented. The proposed transmitter is based on direct conversion to RF architecture, which is known for low power application. Both the transmitters are designed and compared in terms of their performance and efficiency. The simulation results show the BER and constellation plots for both FSK and QPSK transmitter.
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Guilot, Jean-Michel. "In-Flight Wireless Acquisition: an Experience." International Foundation for Telemetering, 2014. http://hdl.handle.net/10150/577464.
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ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CAThe wireless acquisition system LISA has been designed for mechanical phenomenon analysis onboard aircrafts. It has been in use for more than one year now. This paper describes the organization of this equipment and the experiences related by first users.
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Hill, Terrance J. "ANALYTICAL AND EXPERIMENTAL CHARACTERIZATION OF SOQPSK AND MULTI-H CPM IN A MULTIPATH CHANNEL." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/606446.
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International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, NevadaShaped Offset QPSK (SOQPSK) has been shown to be nearly identical in performance to Feher-patented FQPSK, which is the Advanced Range Telemetry (ATRM) program's Tier I waveform. Multi-h CPM has been selected as the ARTM Tier II waveform, because it offers 50% better spectral efficiency than the Tier I waveform. Both the Tier I and Tier II waveforms must operate in a multipath channel in order to meet the range community's telemetry requirements. This paper presents an analytical and experimental characterization of SOQPSK and Multi-h CPM in the presence of multipath. Quantitative results are presented which demonstrate the relative robustness of the ARTM Tier I and Tier II waveforms, in channels representative of a typical range environment.
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Fan, Tiange, Kung Yao, and Don Whiteman. "ADAPTIVE EQUALIZATION FOR OQPSK THROUGH A FREQUENCY SELECTIVE FADING CHANNEL." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606497.
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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, CaliforniaSpectral sidelobes of QPSK, OQPSK, IJF-OQPSK, and SQAM modulated signals after nonlinear amplification are compared. It is known that OQPSK has lower spectral sidelobes than QPSK. However, in the presence of frequency selective fading, a decision-feedback adaptive equalizer is able to equalize the QPSK signal but not the OQPSK signal. By using phase pre-distortion on the OQPSK waveform before nonlinear amplification, not only is the adaptive equalizer able to equalize this signal, its spectral sidelobes are also reduced. Simulations are presented to confirm these results.
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Chaloupka, Tomáš. "Simulace vysokorychlostních optických datových přenosů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-403768.
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The aim of this master thesis is comparation of simulation tools OptSim™ and PHO- TOSS which are used to create simulations of data traffi cs in access and metropolitan networks. The outcome of this thesis is three laboratory exercises and their theoretical bases which should explain the way of working in diff erent simulation environments to students.
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Panhwar, Muhammad Fawad [Verfasser]. "DSP based CD and PMD Equalization Techniques in PDM-QPSK and PDM-16-QAM Receivers / Muhammad Fawad Panhwar." Paderborn : Universitätsbibliothek, 2016. http://d-nb.info/1102246336/34.
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Gao, Wei, and Kamilo Feher. "FQPSK: A BANDWIDTH AND RF POWER EFFICIENT TECHNOLOGY FOR TELEMETRY APPLICATIONS." International Foundation for Telemetering, 1997. http://hdl.handle.net/10150/609731.
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International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, NevadaA simple, low cost radio frequency (RF) power and spectrally efficient integrated transceiver/modem architecture employing Feher’s patented Quadrature Phase Shift Keying (FQPSK) is described. The FQPSK signals presented in this paper are obtained by using additional post low-pass filters in the FQPSK architecture. This implementation significantly improves the spectral efficiency of the worldwide commercially standardized Gaussian Minimum Shift Keying (GMSK) systems. The Bit Error Rate (BER) performance of FQPSK in additive white Gaussian noise (AWGN) channel has been investigated by means of computer simulation and hardware prototype measurements. The results of the hardware and software simulations are compared to GMSK and QPSK/OQPSK performance. These results show that the filtered FQPSK modulated signal passing through a non-linear amplifier (NLA) can achieve a spectral efficiency improvement of about 60% over NLA filtered OQPSK and an integrated spectral efficiency improvement of 50% over GMSK and a better BER performance. In particular, 100 kb/s to 34 Mb/s hardware experimental results over 2.4 GHz NLA (saturated) 1 Watt system confirmed that FQPSK hardware systems attain a BER=f(Eb/N0) performance within 1 dB to 2 dB of predicted theoretical results.
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Carlsson, Erik. "Synchronization of Distributed Units without Access to GPS." Thesis, Linköpings universitet, Datorteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-149653.
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Time synchronization between systems having no external reference can be an issue in small wireless node-based systems. In this thesis a transceiver is designed and implemented in two separate systems. Then the timing algorithm of "TwoWay Time Transfer" is then chosen to correct any timing error between the two free running clocks of the systems. In conclusion the results are compared towards having both systems get their timing based on GPS timing.Tidssynkronisering mellan två system som saknar externa referenser kan bli ett problem i små nodbaserade system. I det här arbetet har en sändtagare designats och implementerats i två system. Sedan valdes algoritmen "TwoWay Time Transfer"för att rätta till de timing fel som uppstår mellan systemens separata klockor.I sammanfattningen så jämnförs uppkommna resultat med att ha systemens tid från GPS.
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Siegrist, Michael. "Aufwandsgünstige Verfahren zur Vorcodierung bei nichtlinearen Übertragungssystemen." Aachen Shaker, 2009. http://d-nb.info/998764582/04.
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Karaki, Julie. "100 Gbps coherent MB-OFDM for long-haul WDM optical transmission." Thesis, Paris, ENST, 2013. http://www.theses.fr/2013ENST0019/document.
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Aujourd'hui, le format « Quadrature Phase Shift Keying » avec multiplexage de polarisation (DP-QPSK) opérant à 100 Gbps est devenue un standard pour la transmission WDM longue distance. Une alternative au format DP-QPSK permettant d’atteindre des débits de 100 Gbps et plus (400 G & 1Tbps) est l’ « Orthogonal Frequency Division Multiplexing » (OFDM). Mais, des interrogations subsistent quant à sa robustesse aux effets non linéaires. Dans cette thèse nous avons étudié le potentiel de la technologie OFDM pour la transmission WDM longue distance à 100 Gbps. Le traitement du signal est détaillé ainsi que la mise en œuvre du transmetteur et récepteur OFDM cohérent. Nous présentons aussi les résultats expérimentaux de la transmission obtenus dans plusieurs configurations. Dans l’une de ces configurations, le canal modulé avec le format DP-OFDM coherent (Co-DP-OFDM) est multiplexé avec 40 canaux modulés en DP-QPSK à 100 Gbps. Les canaux ont ensuite été transmis sur 1000 km de fibre G.652 sans gestion de dispersion chromatique. Dans une autre configuration, les canaux Co-DP-OFDM et Co-DP-QPSK sont combinés avec 78 canaux 10 Gbps NRZ-OOK et transmis sur 1000 km de fibre G.652 avec gestion de dispersion. Nous avons montré que le Co-DP-OFDM et Co-DP-QPSK ont des performances similaires après une transmission de 1000 km sur une ligne sans gestion de dispersion, et nous avons aussi montré que la transmission de ces formats sur une infrastructure de fibre deployée est possible à condition de réduire de 5 dB la puissance des canaux 10 Gbps NRZ-OOK par rapport aux canaux à100 Gbps. Ces résultats sont précieux pour la prochaine génération de systèmes WDM à 400 Gbps ou 1 TbpsToday the 100 Gbps coherent dual polarization quadrature phase shift keying (Co-DP-QPSK) is standardized as the industrial solution for long-haul WDM transmission. Another alternative format to DP-QPSK that permits also to reach a data rate of 100 Gbps and beyond is the coherent orthogonal frequency division multiplexing (OFDM) format. However a doubt exists over the ability of OFDM to be as efficient as QPSK for long-haul WDM transmission due to its supposed higher sensitivity to nonlinear effects . In this thesis, we have investigated the potential of Co-DP-OFDM for 100 Gbps WDM transport. The digital signal processing algorithms are detailed as well as the various experimental set-ups required to carry out and validate the 100 Gbps transceiver. We also present the transmission results obtained with several configurations. In one of these configurations, the 100 Gbps Co-DP-OFDM channel is multiplexed with forty 100 Gbps DP-QPSK channels and all these channels are transmitted over 1000 km of DCF-free G.652 fiber, while in another configuration, the Co-DP-OFDM and Co-DP-QPSK channels are combined with seventy eight 10 Gbps NRZ-OOK channels and transmitted over 1000 km of dispersion managed G.652 fiber line. We have demonstrated that OFDM and QPSK have nearly the same performance after a transmission over 1000 km, and also we have demonstrated that the transmission of these two formats over legacy fiber infrastructure is possible under the condition of decreasing by 5 dB the 10 Gbps NRZ-OOK channel power with respect to the 100 Gbps channels. The results presented in this thesis are very valuable when considering the next generation of 400 Gbps or 1 Tbps for WDM systems
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Booysen, Samuel. "The design of a high speed topology for a QPSK demodulator with emphasis on the synchronization algorithms needed for demodulation." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4107.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: This thesis describes the design and implementation of a software based QPSK demodulator with a demodulation speed of 100 Mbps. The objective of the thesis was to identify a topology for the QPSK demodulator that would allow for high data rates and the design of the synchronization algorithms for carrier and symbol recovery. The QPSK demodulator was implemented on an Altera Stratix II field programmable gate array (FPGA), which does complex I and Q sampling on a down converted 720 MHz QPSK signal. The I and Q down converted baseband signals are sent through matched filters which are implemented with discrete components to maximize the signal to noise ratio of the received rectangular baseband pulses. A 1 GSPS direct digital synthesizer (DDS) is used to generate the synchronous clock for the analog to digital converters which samples the matched filter outputs. The demodulator uses two samples per symbol to demodulate the QPSK signal. A dual locking system is implemented to have a wide pre-locking filter for symbol synchronization and a narrow band post-lock filter to minimize the loop noise. A symbol lock detection algorithm decides when the symbol recovery loop is locked and switches between the loop filters. A second 1 GSPS DDS output is mixed with a local oscillator to generate the 1.44 GHz LO signal for the quadrature down conversion. The carrier recovery loop uses a numerically controlled oscillator inside the FPGA for initial carrier acquisition which allows for very wide locking bandwidth. After lock is achieved, the external carrier recovery loop takes over and removes any frequency offset in the complex baseband signal by changing the frequency of the DDS. A QPSK modulator was also developed to provide a QPSK signal with known data. The modulator can generate any constellation diagram up to 256 points.
AFRIKAANSE OPSOMMING: Hierdie tesis bespreek die ontwerp en implementasie van ’n sagteware gebaseerde QPSK demodulator met ’n demodulasie spoed van 100 Mbps. Die doelstelling is om ’n topologie te identifiseer vir ’n QPSK demodulator wat ’n hoë datatempo sal toelaat en ook om sinkronisasie algoritmes te ontwikkel vir draer en simbool herkenning. Die QPSK demodulator is geïmplimenteer op ’n Stratix II FPGA van Altera wat kompleks basisband monstering doen op infase en kwadratuur basisband seine. Die basisband seine word gegenereer van ’n 720 MHz QPSK sein met ’n kwadratuur menger wiese uittrees deur puls passende filters gestuur word om die sein tot ruis verhouding te maksimeer. ’n Een gigamonster per sekonde direk digitale sintetiseerder (DDS) is gebruik om die klok vir die analoog na digitaal omsetters te genereer vir sinkrone monstering van die pulse passende filter uittrees. Die demodulator gebruik twee monsters per simbool om ’n QPSK sein te demoduleer. ’n Tweevoudige sluit algoritme word gebruik vir die simbool sinkronisasie waar ’n wyeband filter die inisiële sluit funksie verrig en dan word daar oorgeslaan na ’n nouband filter vir fase volging wat die ruis in die terugvoerlus verminder. Daar is ’n simbool sluit detektor wat identifiseer wanneer die simbool beheerlus gesluit is en selekteer dan die gepaste filter. ’n Tweede DDS en ’n sintetiseerder se uittrees word gemeng om ’n 1.44 GHz draer te genereer vir kohurente frekwensie translasie in die kwadratuur menger. Die draer sinkronisasie gebruik ’n numeries beheerbare ossilator vir die inisiële frekwensie en fase sluit wat baie vinnig geimplenteer kan word omdat dit alles in sagteware binne in die FPGA gebeur. Na die interne draer beheerlus gesluit is, neem die eksterne beheerlus oor om enige fase of frekwensie afsette in die kompleks basisband seine van die kwadratuur menger te verwyder deur die frekwensie van die draer DDS te beheer. ’n QPSK modulator is ook ontwikkel om verwysings data te genereer. Enige konstelasie vorm tot 256 punte kan geimplementeer word.
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Wahlgren, Max, and Daniel Forsberg. "Hårdvarubaserade SOQPSK-algoritmer : En VHDL-implementation av algoritmer för att modulera & demodulera SOQPSK-signaler." Thesis, Linköping University, Department of Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-12327.
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Beroende på i vilken miljö man har tänkt att använda trådlös kommunikation behöver man hitta en modulationsteknik som passar under rådande förhållanden. I början på 1980-talet utvecklade den Amerikanska militären en modulationsteknik som kallas för Shaped BPSK (SBPSK) avsedd att tillämpas i kommunikationslänkar med satelliter. Vidareutveckling av SBPSK ledde sedan fram till en förbättrad variant kallad Shaped Offset QPSK (SOQPSK). På senare år har denna modulationsteknik börjat användas i civila tillämpningar och vidareutvecklats ytterligare för att ge den än bättre prestanda. År 2004 antogs SOQPSK som en modulationsteknik i den internationella flygplanskommunikationsstandarden, IRIG-106. Versionen av SOQPSK som antogs i IRIG-106 har flera bra egenskaper som t. ex. dess spektraltäthet. Detta gör denna typ av modulationsteknik lämpad för kommunikationslänkar med bl.a. flygplan, satelliter och rymdsonder (‘deep-space’).
Målet med examensarbetet har varit att implementera algoritmer för att skicka och ta emot SOQPSK-modulerade signaler. Dessa algoritmer skulle utvecklas i VHDL för att sedan syntetiseras och programmera en FPGA. Uppgiften har givits av Syncore Technologies AB i Linköping.
Arbetet har resulterat i fungerande implementationer både i mjukvara och hårdvara. Hårdvarulösningen är verifierad att klara bithastiheter upp till 30 Mbit/s. Teoretisk information om allmän modulering/demodulering och specifikt kring SOQPSK behandlas i rapporten. Uppbyggnaden av en teoretisk sändar- och mottagarmodell utformad för SOQPSK-kommunikation beskrivs också i rapporten för att ge en bättre helhetsbild av implementationen som utförts.
Arbetets syfte är att ligga till grund för Syncore AB som utvecklar en kom- munikationslänk med SOQPSK-kompatibilitet.
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Hill, Terry, and Jim Uetrecht. "SOQPSK with LDPC: Spending Bandwidth to Buy Link Margin." International Foundation for Telemetering, 2013. http://hdl.handle.net/10150/579588.
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ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NVOver the past decade, SOQPSK has been widely adopted by the flight test community, and the low density parity check (LDPC) codes are now in widespread use in many applications. This paper defines the waveform and presents the bit error rate (BER) performance of SOQPSK coupled with a rate 2/3 LDPC code. The scheme described here expands the transmission bandwidth by approximately 56% (which is still 22% less than the legacy PCM/FM modulation), for the benefit of improving link margin by over 10 dB at BER = 10⁻⁶.
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YANG, QI-ZHENG, and 楊建勛. "QPSK modem transmitter part desing." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/27103775622740420487.
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