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1
Lau, Hing-keung. "Pilot-symbol-aided techniques for spectrally efficient signals in multipath-fading channels /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19669161.
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Said, Nezar Ali. "Performance analysis of multi-carrier code division multiple access system in multipath fading channels." Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1176401917.
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劉慶強 and Hing-keung Lau. "Pilot-symbol-aided techniques for spectrally efficient signals in multipath-fading channels." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31237198.
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Ma, Ming. "Multiuser mobile communication systems." Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289069.
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Shi, Lishen. "Coherent optical code division multiple access (CDMA) network employing CW semiconductor lasers." Thesis, University of Strathclyde, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273787.
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Srirattana, Nuttapong. "High-Efficiency Linear RF Power Amplifiers Development." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6899.
Full textAbstract:
Next generation mobile communication systems require the use of linear RF power amplifier for higher data transmission rates. However, linear RF power amplifiers are inherently inefficient and usually require additional circuits or further system adjustments for better efficiency. This dissertation focuses on the development of new efficiency enhancement schemes for linear RF power amplifiers.
The multistage Doherty amplifier technique is proposed to improve the performance of linear RF power amplifiers operated in a low power level. This technique advances the original Doherty amplifier scheme by improving the efficiency at much lower power level. The proposed technique is supported by a new approach in device periphery calculation to reduce AM/AM distortion and a further improvement of linearity by the bias adaptation concept.
The device periphery adjustment technique for efficiency enhancement of power amplifier integrated circuits is also proposed in this work. The concept is clearly explained together with its implementation on CMOS and SiGe RF power amplifier designs. Furthermore, linearity improvement technique using the cancellation of nonlinear terms is proposed for the CMOS power amplifier in combination with the efficiency enhancement technique.
In addition to the efficiency enhancement of power amplifiers, a scalable large-signal MOSFET model using the modified BSIM3v3 approach is proposed. A new scalable substrate network model is developed to enhance the accuracy of the BSIM3v3 model in RF and microwave applications. The proposed model simplifies the modeling of substrate coupling effects in MOS transistor and provides great accuracy in both small-signal and large-signal performances.
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Sivanesan, Kathiravetpillai. "A study of performance for M-ary DS/CDMA cellular mobile radio systems." Click to view the E-thesis via HKUTO, 1999. http://sunzi.lib.hku.hk/hkuto/record/B42575333.
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鄭价昌 and Kai-cheong Chang. "Adaptive channel equalisation technique for wideband time-division multiple access digital mobile radio communications systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31212888.
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Chang, Kai-cheong. "Adaptive channel equalisation technique for wideband time-division multiple access digital mobile radio communications systems /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17590371.
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Ward, Richard Peter. "Evolution of loosely synchronized spreading codes in code-division multiple-access systems." Thesis, University of South Wales, 2008. https://pure.southwales.ac.uk/en/studentthesis/evolution-of-loosely-synchronized-spreading-codes-in-codedivision-multipleaccess-systems(2bf79128-319c-49c1-8246-91ee0d3533c4).html.
Full textAbstract:
Loosely Synchronized (LS) codes can be used as spreading codes in quasi synchronous code-division multiple-access (QS-CDMA) systems. In such CDMA systems, close control of synchronization is achieved at the chip level, interme diate between that in synchronous CDMA and that in asynchronous CDMA. The LS code can then capitalize on zero correlation in a limited synchronization window to reduce code correlations and so reduce interference. LS codes are {O, +1, -1} codes constructed using Hadamard matrices and Golay pairs. A variation of LS codes inserts short strings of zeros between the components of the Golay pairs to increase the number of codewords, with only limited dete rioration in the correlations. These strings of zeros are known as internal padding. One of the advantages normally claimed for CDMA systems is resistance to eavesdropping and jamming. It might appear at first sight that the structure of LS codes is rather predictable in comparison with codes constructed using linear feedback shift registers, such as m-sequences or Gold codes. One way to overcome any such difficulty would be to evolve the code very quickly, in such a way that by the time a generation of the code is determined (or determined to a moderate correlation value) it is too late to exploit it. This thesis explores the way that LS codes can be evolved in order to achieve resistance to eavesdropping and jamming. The thesis starts with a detailed account of the necessary background and of the construction of Loosely Synchronized codes. The early part of the thesis then concentrates on showing that many generations of LS code can be constructed in such a way that the correlation between distinct generations is small. This prevents one observed generation of the code from being used for jamming or prediction in another generation. Specifically: •The construction of Golay pairs is investigated and a search is carried out over all possible Golay pairs and their mates to find a set of pairs that leads to the satisfaction of a suitable correlation criterion; •Bent functions, almost bent functions and other second order Boolean functions are used to create sets of Hadamard matrices that are guaranteed to satisfy the same correlation criterion; •A sequential search method to generate a set of arrangements of the internal padding that satisfies the same correlation criterion is described. Later in the thesis this approach is replaced by a recency list approach. This ensures that the correlation criterion is satisfied against recently used generations of the code, in place of all generations of the code; •The way in which these evolutions of the components combine together is also explored. Attention turns in the second part of the thesis to the mechanisms for evolution and the way that these might be predicted by a third party observer. Transform methods that the third party might use are described. Detailed simulations quantify the ability of the third party to identify the code during the transmission of a single bit. It is shown that theoretical resistance to early code prediction is not possible, although it might be possible to demonstrate security arising from the relative speed of the necessary computations for the user and the observer. This would require a detailed hardware study, and this is listed as future work. In fact it is shown here that LS codes are actually better than linear feedback shift register codes, as a result of the Berlekamp-Massey algorithm. Attention is also focussed on the scenario in which details of the algorithms of one user are obtained by the third party. Only the Hadamard matrix provides protection against this scenario, as all other components of the construction are shared between all users. From this second viewpoint the true weakness of LS codes becomes apparent. Although the Hadamard matrix constructions are satisfactory if the order of the Hadamard matrix is not too small, it seems that the sequence of Hadamard matrix rows of each user must be computed centrally and distributed to users as private keys if this scenario is not to remain a major concern. The volume of private key distribution necessary may seem unattractive to operators. Ultimately it seems that evolution of the Golay pairs may have little real role except to increase the workload of the observer. The recency list based evolution of internal padding can take the main role in ensuring low correlation between close generations of the code. The evolution of the Hadamard matrix should be designed to concentrate on the second viewpoint, where the third party has obtained details of the algorithms of one user.
11
Seow, Tian Beng. "Circular antenna array applications in coded DS-CDMA mobile communication systems /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FSeow.pdf.
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Ng, Stewart Siew Loon. "Smart antenna in DS-CDMA mobile communication system using circular array /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FNg.pdf.
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Chen, Jun, and 陳軍. "Multicode CDMA for high-speed mobile communications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B30149903.
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Chen, Jun. "Multicode CDMA for high-speed mobile communications /." Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25151241.
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Ng, Kok Keng. "Smart antenna application in DS-CDMA mobile communication system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02sep%5FNg.pdf.
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Zheng, Raymond Sihao. "Channel modeling and interference rejection for CDMA automatic vehicle monitoring systems." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-07112009-040511/.
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Wu, Jingxian. "Optimum receiver design and performance analysis for wireless communication." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4177.
Full textAbstract:
Thesis (Ph. D.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (July 19, 2006) Vita. Includes bibliographical references.
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Wang, Xiangyang, and 王向陽. "Transmit diversity in CDMA for wireless communications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31246072.
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Jatunov, Loran Aleksandrovich. "Unified Performance Analysis for Third-Generation CDMA Systems." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5212.
Full textAbstract:
Analytic models for the performance of the forward link of 3G CDMA
systems using different maximum ratio combining (MRC) RAKE finger
weight assignments are presented. The spreading modulations under
investigation are the balanced QPSK and the complex-spreading QPSK.
The models are computationally efficient, accurate, and
applicable to Root Raised Cosine (RRC) pulse shaping with any
roll-off factor, variable processing gain, chip rate, and data
rate for orthogonal codes, random codes, quasi-orthogonal codes,
Gaussian noise, and realistic channel models. The expressions
derived are then used to obtain the so-called orthogonality
factor, which is commonly used in system-level simulations.
Next, closed-form mathematical expressions for the variance due to
infinite chips interfering in systems using arbitrary Nyquist
pulses are derived. These expressions are applicable to both the
forward link and the reverse link. For the latter, the existing
knowledge on the accurate and efficient estimation of the
performance of CDMA systems is extended by presenting closed
mathematical expressions for bandlimited systems using arbitrary
Nyquist pulses for both BPSK and Offset-QPSK (OQPSK)
modulation. The impact
of adjacent channel interference in bandlimited systems is
subsequently considered. Finally, mathematical expressions for the
accurate and efficient estimation of a CDMA system using RRC
pulse-shaping and a RAKE receiver in the presence of multipath
interference are presented.
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Garcia, Garcia Núria 1958. "Radio Resource Management strategies based hopfield neural networks." Doctoral thesis, Universitat Pompeu Fabra, 2009. http://hdl.handle.net/10803/7556.
Full textAbstract:
Esta tesis doctoral se enmarca en la temática de Gestion de Recursos Radioelectricos en los sistemas de comunicaciones móviles, 3G, B3G y 4G. Como es ampliamente conocido los recursos radios son escasos, particularmente en los sistemas de comunicaciones móviles celulares, y en consecuencia es de uso obligado una gestión eficiente de los mismos. Desde un punto de vista práctico si bien estos sistemas se basan en el uso de tecnologías de acceso radio estandarizada, no es este el caso para los algoritmos subyacentes a la gestión de los recursos radio, de manera que siempre son posibles nuevas realizaciones de los mismos que resulten más convenientes en el marco del estándar en cuestión. Es en esta dirección hacia donde apunta la realización de esta tesis doctoral, y entiendo que lo consigue con éxito al introducir nuevas estrategias de Gestion de los Recursos Radio en el marco de las estrategias de múltiple acceso CDMA en los sistemas 3G, TDMA/CDMA en los sistemas B3G y OFDMA en los sistemas 4G. Esta tesis, tras identificar los gestores más usuales de gestión de recursos radio y una breve descripción de los mismos, introduce una descripción básicamente autocontenida de los aspectos más relevantes de los sistemas de acceso múltiple WCDMA y OFDMA. En este sentido se detallan mecanismos de su funcionamiento que con posterioridad serán utilizados en la definición y especificación de los algoritmos de gestión de recursos propiamente dichos. Con posterioridad se hace un breve recorrido sobre lo que son las redes neuronales , para finalizar en una exposición más detallada de las Redes Neuronales de Hopfield que serán el hilo conductor de los trabajos de esta tesis. En particular se describen las ecuaciones que caracterizan estas redes como sistemas dinámicos y se establecen sus condiciones de convergencia a través de los teoremas de estabilidad Lyapunov y la definición de la función Energía.De la conjunción de las particularidades de los sistemas de acceso WCDMA, TDMA y OFDMA y de las redes neuronales de Hopfield se van desarrollando una serie de algoritmos que operan en escenarios unicelulares y que entiendo novedosos y que a continuación enumeran brevemente.Admisión en un sistema WCDMA , enlace ascendente, mediante una gestión optimizada de las distintas velocidades de transmisión asignadas a los usuarios que comparten el acceso y que se les permite distintos perfiles. Aspectos relativos a la robustez del algoritmo, y en particular a su convergencia son también detallados. Se suponen restricciones de carga de la red máxima, repartición del espectro justa y potencia máxima disponible en los terminales móviles. Se suponen un servicio en tiempo real con velocidades variables. La probabilidad de bloqueo se usa para exhibir las prestaciones del algoritmo.Gestión de las velocidades de los usuarios ya admitidos en un sistema WCDMA,enlace ascendente, con objeto de garantizarles una definida probabilidad de satisfacción superior a un determinado valor y que está basada en las velocidades reales de transmisión asignadas. Se supone también un servicio en tiempo real con velocidades variables y las mismas restricciones que en Admisión. Gestión de las velocidades de los usuarios ya admitidos en un sistema WCDMA, enlace descendente, con objeto de garantizarles un máximo retardo en la entrega de paquetes. Se suponen restricciones de repartición del espectro justa y potencia máxima disponible en la estación de base. Se supone un servicio interactivo basado en un modelo de tráfico para servicios www. Se introduce también un algoritmo de referencia a efectos comparativos. La probabilidad de pérdida es el parámetro usado para valorar las prestaciones del algoritmo.Gestión combinada de servicios en tiempo real e interactivos en sistemas WCDMA, enlace descendente. Incorpora parte de los algoritmos anteriormente enunciados y se mantienen los mismos modelos de tráfico y las mismas restricciones. Se han usado en esta caso las probabilidades de satisfacción y de pérdida para capturar el la velocidad de transmisión agregada y retardo respectivamente Algoritmo de Gestión común de recursos radio para un escenario B3G donde un usuario puede ser servido por más de un acceso. En este caso se han usado WCDMA y TDMA. Algoritmos de Gestión de las velocidades de los usuarios ya admitidos en un sistema OFDMA, enlace descendente, con objeto de garantizarles un máximo retardo en la entrega de paquetes.La tesis apunta también hacia prometedoras futuras líneas de investigación que pretenden explotar la base de la metodología desarrollada en esta tesis y que consisten en escenarios celulares centralizadas para pasar después a distribuidas en entornos multicelulares y en particular para los sistemas OFDMA , base de los accesos en 4G.
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"Cell sectoring for CDMA cellular systems." 2002. http://library.cuhk.edu.hk/record=b5891214.
Full textAbstract:
Shen Fangzhong.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.
Includes bibliographical references (leaves 55-57).
Abstracts in English and Chinese.
Abstract --- p.i
Acknowledgements --- p.iii
List of Figures --- p.vi
List of Tables --- p.ix
Chapter Chapter 1. --- Introduction --- p.1
Chapter 1.1. --- Motivation --- p.1
Chapter 1.2. --- Related Work --- p.2
Chapter 1.3. --- Our Work --- p.2
Chapter 1.4. --- Some Assumptions --- p.2
Chapter 1.4.1. --- Beamforming --- p.2
Chapter 1.4.2. --- Downlink Channel --- p.2
Chapter 1.4.3. --- Single Cell --- p.3
Chapter 1.5. --- Thesis Road Map --- p.3
Chapter Chapter 2. --- Preliminaries of Cell Sectoring --- p.4
Chapter 2.1. --- Introduction --- p.4
Chapter 2.2. --- Beamforming --- p.4
Chapter 2.2.1. --- Linear Array --- p.5
Chapter 2.2.2. --- Circular Array --- p.8
Chapter 2.2.3. --- Butler Beamforming Network --- p.9
Chapter 2.2.4. --- Dynamic Beamforming --- p.10
Chapter 2.3. --- Power Control --- p.16
Chapter Chapter 3. --- Dynamic Cell Sectoring --- p.19
Chapter 3.1. --- Introduction --- p.19
Chapter 3.2. --- Minimum Total Transmission Power sectoring --- p.21
Chapter 3.2.1. --- Problem Statement --- p.21
Chapter 3.2.2. --- Shortest Path Problem Formulation --- p.23
Chapter 3.2.3. --- Shortest Path Algorithm and Complexity --- p.26
Chapter 3.2.4. --- Graph Reduction --- p.28
Chapter 3.2.5. --- Example --- p.30
Chapter 3.3. --- Power Equalization Sectoring --- p.33
Chapter 3.3.1. --- Relationship Between MinTTP Sectoring and PE Sectoring --- p.33
Chapter 3.3.2. --- Power Equalization Sectoring Algorithm --- p.36
Chapter 3.4. --- Numerical Results --- p.37
Appendix --- p.44
Chapter Chapter 4. --- Resectoring Algorithms --- p.46
Chapter 4.1. --- Introduction --- p.46
Chapter 4.2. --- Nyquist Sampling Theorem --- p.47
Chapter 4.3. --- MinTTP Resectoring --- p.47
Chapter 4.4. --- PE Resectoring --- p.43
Chapter 4.5. --- Handoff --- p.48
Chapter 4.5.1. --- Handoff Load --- p.49
Chapter 4.6. --- Performance --- p.49
Chapter Chapter 5. --- Conclusion and Future Work --- p.53
Chapter 5.1. --- Thesis Summary --- p.53
Chapter 5.2. --- Future Work --- p.54
Bibliography --- p.55
22
"Novel self-decorrelation and fractional self-decorrelation pre-processing techniques to enhance the output SINR of single-user-type DS-CDMA detectors in blind space-time RAKE receivers." 2002. http://library.cuhk.edu.hk/record=b5891142.
Full textAbstract:
Cheung Shun Keung.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.
Includes bibliographical references (leaves 80-83).
Abstracts in English and Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- The Problem --- p.1
Chapter 1.2 --- Overview of CDMA --- p.2
Chapter 1.3 --- Problems Encountered in Direct-Sequence (DS)CDMA --- p.3
Chapter 1.3.1 --- Multipath Fading Scenario in DS-CDMA Cellular Mo- bile Communication --- p.3
Chapter 1.3.2 --- Near-Far Problem --- p.4
Chapter 1.4 --- Delimitation and Significance of the Thesis --- p.5
Chapter 1.5 --- Summary --- p.7
Chapter 1.6 --- Scope of the Thesis --- p.8
Chapter 2 --- Literature Review of Blind Space-Time Processing in a wire- less CDMA Receiver --- p.9
Chapter 2.1 --- General Background Information --- p.9
Chapter 2.1.1 --- Time Model of K-User Chip-Synchronous CDMA --- p.9
Chapter 2.1.2 --- Dispersive Channel Modelling --- p.10
Chapter 2.1.3 --- Combination of K-user CDMA Time Model with the Slow Frequency-Selective Fading Channel Model to form a completed Chip-Synchronous CDMA Time Model --- p.13
Chapter 2.1.4 --- Spatial Channel Model with Antenna Array [9] --- p.15
Chapter 2.1.5 --- Joint Space-Time Channel Model in Chip-Synchronous CDMA --- p.19
Chapter 2.1.6 --- Challenges to Blind Space-Time Processing in a base- station CDMA Receiver --- p.23
Chapter 2.2 --- Literature Review of Single-User-Type Detectors used in Blind Space-Time DS-CDMA RAKE Receivers --- p.25
Chapter 2.2.1 --- A Common Problem among the Signal Processing Schemes --- p.28
Chapter 3 --- "Novel ""Self-Decorrelation"" Technique" --- p.29
Chapter 3.1 --- "Problem with ""Blind"" Space-Time RAKE Processing Using Single- User-Type Detectors" --- p.29
Chapter 3.2 --- "Review of Zoltowski & Ramos[10,11,12] Maximum-SINR Single- User-Type CDMA Blind RAKE Receiver Schemes" --- p.31
Chapter 3.2.1 --- Space-Time Data Model --- p.31
Chapter 3.2.2 --- The Blind Element-Space-Only (ESO) RAKE Receiver with Self-Decorrelation Pre-processing Applied --- p.32
Chapter 3.3 --- Physical Meaning of Self-Decorrelation Pre-processing --- p.35
Chapter 3.4 --- Simulation Results --- p.38
Chapter 4 --- """Fractional Self-Decorrelation"" Pre-processing" --- p.45
Chapter 4.1 --- The Blind Maximum-SINR RAKE Receivers in Chen et. al.[l] and Wong et. al.[2] --- p.45
Chapter 4.2 --- Fractional Self-Decorrelation Pre-processing --- p.47
Chapter 4.3 --- The Blind Element-Space-Only (ESO) RAKE Receiver with Fractional Self-Decorrelation Pre-processing Applied --- p.50
Chapter 4.4 --- Physical Meaning of Fractional Self-Decorrelation Pre-processing --- p.54
Chapter 4.5 --- Simulation Results --- p.55
Chapter 5 --- Complexity Analysis and Schematics of Proposed Techniques --- p.64
Chapter 5.1 --- Computational Complexity --- p.64
Chapter 5.1.1 --- Self-Decorrelation Applied in Element-Space-Only (ESO) RAKE Receiver --- p.64
Chapter 5.1.2 --- Fractional Self-Decorrelation Applied in Element-Space- Only (ESO) RAKE Receiver --- p.67
Chapter 5.2 --- Schematics of the Two Proposed Techniques --- p.69
Chapter 6 --- Summary and Conclusion --- p.74
Chapter 6.1 --- Summary of the Thesis --- p.74
Chapter 6.1.1 --- The Self-Decorrelation Pre-processing Technique --- p.75
Chapter 6.1.2 --- The Fractional Self-Decorrelation Pre-processing Tech- nique --- p.76
Chapter 6.2 --- Conclusion --- p.78
Chapter 6.3 --- Future Work --- p.78
Bibliography --- p.80
Chapter A --- Generalized Eigenvalue Problem --- p.84
Chapter A.1 --- Standard Eigenvalue Problem --- p.84
Chapter A.2 --- Generalized Eigenvalue Problem --- p.84
23
Ellis, Timothy. "The implementation of a CDMA system on a FPGA-based software radio." Thesis, 2000. http://hdl.handle.net/10413/5252.
Full textAbstract:
This dissertation exammes two of the rlsing technologies in the world of wireless, cellular
communications - CDMA and the software radio. This thesis covers many of the issues related
to these two emerging field s of wireless communications, establish ing a theoretical framework
for the broader issues of implementation. To this end, the thesis covers many of the basic issues
of spread spectrum communications, in addition to establishing the need for, and defining the
role of, the software radio. Amalgamation of these two key areas of interest is embellished in a
presentation of many of the concerns of implementing a specific CDMA system on a particular
type of software radio - the Alcatel Altech Telecomms Flexible Radio Platform.
Of primary concern in the research methodology embraced in this thesis is the mastering of a
variety of analysis and implementation tools. Once the theoretical background has been
substantiated by current expositions, the thesis launches along a highly deterministic route.
First, the research issues are tested in a mathematical environment for suitability to the given
task. Second, an analysis of the appropriateness of the technique for the software radio
environment is undertaken, culminating in the attempted deployment within the hardware
environmenl. Rigorous testing of the input/output mapping characteristics of the hardware
instantiations created in this manner complements the research methodology with a viability
study. This procedure is repeated with many elements of the CDMA system design as they are
examined, simu lated, deployed and tested.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2000.
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Kora, Saju P. "Implementation of a WCDMA AAA receiver on an FPGA based software radio platform." Thesis, 2001. http://hdl.handle.net/10413/8972.
Full textAbstract:
WCDMA promises to achieve high-speed internet, high quality image transmission and
high-speed data services with larger system capacity. However, Multiple Access
Interference is one of the major causes of transmission impairment, which reduces the
link capacity in WCDMA systems. The Adaptive Antenna Array (AAA) technique
reduces multiple access interference by directing antenna beam nulls towards the
interfering signals by weighting the received signals from all antennas before
combining the signals.
With the very rapid advancement of wireless personal communications services, a new
challenge to the cellular industry is the integration of multiple systems and applications
on a single device. A software radio technique offers a possible solution to achieve this
goal including international roaming and multiple standard operations within the same
geographical area. The main attraction of a software radio is it's flexibility, in that it
can be programmed for emerging cellular standards allowing it to be updated with new
software without any changes in the hardware infrastructure. A software radio
incorporating adaptive array beamforming at the receiver can increase the total carried
traffic in a system and transmit power while the probability of call blocking and forced
termination can also be decreased.
This dissertation examines WCDMA, AAA, power control and software radio
techniques in the world of wireless communication systems. Once the theoretical
background of CDMA and AAA has been substantiated, the thesis establishes the need
for power control in mobile systems by examining simulation results. An AAA receiver with six antenna elements is proposed and evaluated in different
environments as a precursor to implementation. It can be inferred that when the link is
interference limited, the link capacity can be increased and it has been shown that the
AAA receiver with six antenna elements increases the link capacity to about 2.9 times
that of the single antenna RAKE receiver.
This thesis also examines the basic concepts of VHDL and considers this as the
principle means to program reconfigurable core FPGA's in the software radio. A three-layered
(PC/DSP/FPGA) software radio test bed is used to implement an AAA
receiver. The architecture of the test bed is designed in such a way that it can be used to
evaluate the performance of various FPGA based transceivers and coding schemes etc.
Many of the desirable features and flexibilities inherent in the software radio concept
are available on this test bed and the system has proved to be capable of high speed
digital processing and is ideally suited to the development of time critical system
components. The bit error rate achieved using the implemented receiver is assessed and
compared to simulation results in an environment incorporating Rayleigh fading and
AWGN.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2001.
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Scriba, Stefan Martin. "Scheduling in CDMA-based wireless packet networks." Thesis, 2003. http://hdl.handle.net/10413/4206.
Full textAbstract:
Modern networks carry a wide range of different data types, each with its own individual
requirements. The scheduler plays an important role in enabling a network to meet all
these requirements. In wired networks a large amount of research has been performed
on various schedulers, most of which belong to the family of General Processor Sharing
(GPS) schedulers. In this dissertation we briefly discuss the work that has been done on a
range of wired schedulers, which all attempt to differentiate between heterogeneous traffic.
In the world of wireless communications the scheduler plays a very important role, since
it can take channel conditions into account to further improve the performance of the
network. The main focus of this dissertation is to introduce schedulers, which attempt to
meet the Quality of Service requirements of various data types in a wireless environment.
Examples of schedulers that take channel conditions into account are the Modified Largest
Weighted Delay First (M-LWDF), as well as a new scheduler introduced in this dissertation,
known as the Wireless Fair Largest Weighted Delay First (WF-LWDF) algorithm.
The two schemes are studied in detail and a comparison of their throughput, delay, power,
and packet dropping performance is made through a range of simulations. The results are
compared to the performance offour other schedulers. The fairness ofM-LWDF and WFLWDF
is determined through simulations. The throughput results are used to establish
Chernoff bounds of the fairness of these two algorithms. Finally, a summary is given of the
published delay bounds of various schedulers, and the tightness of the resultant bounds is
discussed.Thesis (M.Sc. Eng.)-University of Natal, Durban, 2003.
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Pandey, Arvind Nath. "Effect of negative spatial/temporal correlation on the performance of maximal ratio combining in a WCDMA cellular system." Diss., 2003. http://hdl.handle.net/2263/28079.
Full textAbstract:
Please read the abstract in the section 00front of this documentDissertation (M Eng (Electronic Engineering))--University of Pretoria, 2005.
Electrical, Electronic and Computer Engineering
unrestricted
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Singh, Navin Runjit. "Multiuser demodulation for DS-CDMA systems in fading channels." Thesis, 2000. http://hdl.handle.net/10413/5534.
Full textAbstract:
The problems of optimal as well as suboptimal detection for CDMA
transmissions over an additive white Gaussian noise (AWGN) channel, have
been the focus of study in the recent past. However, CDMA transmissions
are frequently made over channels which exhibit fading and/or dispersion;
hence receivers need to be designed which take into account this behaviour.
In spite of the major research effort invested in multiuser demodulation
techniques, several practical as well as theoretical open problems still exist.
Some of them are considered in more detail in this thesis. The aim of the
thesis is to develop multiuser demodulation algorithms for mobile
communication systems in frequency-selective fading channels, and to
analyze their implementation complexity. The emphasis is restricted to the
uplink of an asynchronous DS-CDMA system where the users transmit in an
uncoordinated manner and are received by one centralized receiver.
The original work that is undertaken for the MScEng study is the evaluation
of a multiuser receiver structure for a frequency-selective fading channel,
where there exists a steady specular path and two fading paths.
Furthermore, the effect of using selection diversity is investigated by
examining the bit error rate, asymptotic multi user efficiency and near-far
resistance of the proposed detector structure. These results are confirmed
both analytically and by simulation in the thesis. An investigation is also
conducted into the application of neural networks to the problem of
multiuser detection in code division multiple access systems. The neural
network will be used as a classifier in an adaptive receiver which
incorporates an extended Kalman filter for joint amplitude and delay
estimation. Finally, some open problems for future research will be pointed
out in the thesis.
Keywords: AWGN channel , DS-CDMA system, frequency-selective,
multi user demodulation, asymptotic multiuser efficiency, near-far resistance,
neural network, Kalman filter.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2000.
28
"Code time division multiple access for multicarrier communication systems." 2004. http://library.cuhk.edu.hk/record=b5891853.
Full textAbstract:
Huang Yi.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.
Includes bibliographical references (leaves 97-98).
Abstracts in English and Chinese.
Abstract --- p.i
摘要 --- p.iii
Acknowledgments --- p.iv
Contents --- p.v
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- CTDMA for Multicarrier Communication Systems --- p.2
Chapter 1.2 --- Contributions of This Thesis --- p.4
Chapter 1.3 --- Outline of This Thesis --- p.6
Chapter Chapter 2 --- Multicarrier Communication Systems --- p.8
Chapter 2.1 --- Multicarrier Modulation (MCM) Scheme versus Single Carrier Modulation (SCM) Scheme --- p.9
Chapter 2.2 --- Orthogonal Frequency Division Multiplexing (OFDM) Systems --- p.12
Chapter 2.3 --- Multicarrier CDMA --- p.16
Chapter Chapter 3 --- Data Rate Guaranteed CTDMA for Multicarrier Communication Systems --- p.21
Chapter 3.1 --- Code Time Division Multiple Access (CTDMA) --- p.22
Chapter 3.2 --- Mathematical Programming --- p.28
Chapter 3.3 --- Near Optimal CTDMA Approach --- p.32
Chapter 3.4 --- Ad Hoc CTDMA Approach --- p.48
Chapter 3.5 --- Lower Bound on Optimization --- p.61
Chapter 3.6 --- Performance Evaluation --- p.64
Chapter Chapter 4 --- Code Assignment for Multicarrier Communication Systems with Quantized Feedback --- p.73
Chapter 4.1 --- Code Assignment for Fully Loaded Systems --- p.74
Chapter 4.2 --- Random Orthogonal Codes --- p.76
Chapter 4.3 --- Wireless Fading Channel Model --- p.78
Chapter 4.4 --- Performance Evaluation of One-to-one Assignment --- p.80
Chapter 4.5 --- Code Assignment for Non-fully Loaded Systems --- p.89
Chapter 4.6 --- Performance Evaluation of Multiple-to-one Assignment --- p.90
References --- p.97
29
Syed, Jameel. "Effect of amplifier non-linearity on the performance of CDMA communication systems in a Rayleigh fading environment /." 2009. http://hdl.handle.net/10413/936.
Full text
30
"Random access technology and code assignment schemes for UTRA systems." 2002. http://library.cuhk.edu.hk/record=b6073473.
Full textAbstract:
Yang Yang."July 2002."
Thesis (Ph.D.)--Chinese University of Hong Kong, 2002.
Includes bibliographical references (2nd gr., p. 1-9).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
Abstracts in English and Chinese.
31
Kurniawan, Adit. "Predictive power control in CDMA systems." 2003. http://arrow.unisa.edu.au:8081/1959.8/24961.
Full textAbstract:
This study is aimed at solving several important problems relating to power control in CDMA systems. Our focus is on the mobile to basestation (reverse) link. In this study, we propose a new SIR estimator for CDMA systems, using an auxiliary spreading sequence method. The proposed SIR estimator is employed at the basestation to estimate the SIR, which serves as a control parameter in the power control algorithm. The effects of system parameters (step size, power-update rate, feedback delay, SIR measurement error, and command error) on the bit error rate (BER) performance of power control are investigated. Feedback delay is found to be the most critical parameter that causes a serious problem in the loop. To solve this problem, we propose to use a channel prediction technique at the basestation. To further improve the performance of power control, we then propose to use a diversity reception technique using antenna arrays at the basestation. We show that this combination allows solving the problems linked to the use of power control in a real system affected by multiple access interference under fading conditions.thesis (PhD)--University of South Australia, 2003.
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Conti, Peter G., University of Western Sydney, College of Health and Science, and School of Engineering. "CDMA systems using zero correlation zone codes." 2006. http://handle.uws.edu.au:8081/1959.7/12836.
Full textAbstract:
Zero-Correlation-Zone (ZCZ) codes differ from traditional spreading codes because they contain a region in their correlation functions where the correlation values are null. In these regions the spreading codes are considered ideal, and because of the ZCZ the inter-symbol interference (ISI) and multiple-access interference (MAI) are reduced leading to an increase in capacity and bitrate. This thesis will present a study of ZCZ codes and then will propose a new CDMA system that employs the use of ZCZ codes in particular Loosely Synchronous (LS) codes. This new system shall have its performance compared with an equivalent existing CDMA system (IS-95) and the results shall be shown and discussed. In this comparative study the thesis will also present and examine a tracking performance comparison between ZCZ codes and a traditional spreading code such as m-sequences. It is shown that the performance of the new CDMA system employing ZCZ codes outperforms the traditional CDMA system in a multi-user multipath environment. It is also found that based on the study performed there appears to be no advantage in tracking between a ZCZ code and m-sequences however a more comprehensive study in a multi-user environment is still needed before a conclusion on tracking can be made.Master of Engineering (Hons.)
33
Yang, Xiangying De Veciana Gustavo A. "CDMA ad hoc networks design and performance tradeoffs /." 2005. http://repositories.lib.utexas.edu/bitstream/handle/2152/2200/yangx43299.pdf.
Full text
34
Yang, Xiangying. "CDMA ad hoc networks: design and performance tradeoffs." Thesis, 2005. http://hdl.handle.net/2152/2200.
Full text
35
Rasello, Poloko Freddy. "CDMA performance for a rural telecommunication access." Thesis, 2005. http://hdl.handle.net/10413/8997.
Full textAbstract:
Reviews of possible telecommunication services that can be deployed in the rural areas
are highlighted. These services range from narrowband to broadband. The aim of these
services is to target rural Kwazulu-Natal areas that are without or with limited
telecommunications infrastructure.
Policies that govern telecommunications in South Africa are also reviewed with emphasis
on Universal Service Obligation. The importance of telecommunications infrastructure in
rural areas is also reviewed to the benefit of Kwazulu-Natal.
FDMA, TDMA, CDMA, VSAT, MMDS and MVDS are compared for a possible use in
rural areas. Cost comparison of GSM and CDMA is conducted with emphasis on fade
margin, path loss and penetration rate.
CDMA system design and coverage areas are discussed for rural KwaZulu-Natal. Lastly
bit error rate graphs and power control algorithms are presented for Kwazulu-Natal
scenario.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2005.
36
"Spreading factor optimization and random access stability control for IMT-2000." 2000. http://library.cuhk.edu.hk/record=b5890392.
Full textAbstract:
Ho Chi-Fong.Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.
Includes bibliographical references (leaves 63-[64]).
Abstracts in English and Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Introduction --- p.1
Chapter 1.2 --- The 2.5G Systems --- p.3
Chapter 1.2.1 --- HSCSD --- p.3
Chapter 1.2.2 --- GPRS --- p.3
Chapter 1.2.3 --- EDGE --- p.4
Chapter 1.2.4 --- IS-136 --- p.4
Chapter 1.3 --- The Evolution from 2G/2.5G to 3G --- p.4
Chapter 1.3.1 --- GSM Data Evolution --- p.4
Chapter 1.3.2 --- TDMA Data Evolution --- p.5
Chapter 1.3.3 --- CDMA Data Evolution --- p.6
Chapter 1.4 --- UTRA --- p.7
Chapter 1.4.1 --- UTRA FDD --- p.8
Chapter 1.4.2 --- UTRA TDD --- p.18
Chapter 1.4.3 --- Transport Channels --- p.25
Chapter 2 --- Spreading Factor Optimization for FDD Downlink --- p.27
Chapter 2.1 --- The Optimal Channel Splitting Problem --- p.28
Chapter 2.2 --- Spreading Factor Optimization for FDD Downlink Dedicated Chan- nel --- p.30
Chapter 3 --- Random Access Channel Stability Control --- p.33
Chapter 3.1 --- Random Access Slotted Aloha --- p.33
Chapter 3.1.1 --- System model --- p.33
Chapter 3.1.2 --- Probability of Code-Collision --- p.34
Chapter 3.1.3 --- Throughput Analysis of Random Access in TD/CDMA System --- p.37
Chapter 3.1.4 --- Retransmission --- p.42
Chapter 3.1.5 --- System Delay --- p.42
Chapter 3.2 --- Random Access Channel Stability Control --- p.43
Chapter 3.2.1 --- System Model --- p.43
Chapter 3.2.2 --- Random Access Procedure --- p.44
Chapter 3.3 --- Random Access Channel Stability Control Alogrithm --- p.47
Chapter 3.3.1 --- Simulation --- p.49
Chapter 3.4 --- Multi-class Model --- p.55
Chapter 4 --- Conclusions and Topics for Future Study --- p.60
Chapter 4.1 --- Thesis Conclusions --- p.60
Chapter 4.2 --- Future Work --- p.61
Chapter 4.2.1 --- Downlink and Uplink resource allocation in TDD --- p.61
Chapter 4.2.2 --- Resource Unit Packing in TDD --- p.62
Chapter 4.2.3 --- Other Topics --- p.62
Bibliography --- p.63
37
"Effect of amplifier non-linearity on the performance of CDMA communication systems in a Rayleigh fading environment." Thesis, 2010. http://hdl.handle.net/10413/744.
Full text
38
Judge, Garth. "Protocols for voice/data integration in a CDMA packet radio network." Thesis, 1999. http://hdl.handle.net/10413/6897.
Full textAbstract:
Wireless cellular communications is witnessing a rapid growth in, and demand for,
improved technology and range of information types and services. Future third
generation cellular networks are expected to provide mobile users with ubiquitous
wireless access to a global backbone architecture that carries a wide variety of electronic
services. This thesis examines the topic of multiple access protocols and models
suitable for modem third-generation wireless networks.
The major part of this thesis is based on a proposed Medium Access Control (MAC)
protocol for a Code Division Multiple Access (CDMA) data packet radio network, as
CDMA technology is proving to be a promising and attractive approach for spectrally
efficient, economical and high quality digital communications wireless networks. The
proposed MAC policy considers a novel dual CDMA threshold model based on the
Multiple Access Interference (MAl) capacity of the system. This protocol is then
extended to accommodate a mixed voice/data traffic network in which variable length
data messages share a common CDMA channel with voice users, and where the voice
activity factor of human speech is exploited to improve the data network performance.
For the protocol evaluation, the expected voice call blocking probability, expected data
throughput and expected data message delay are considered, for both a perfect channel
and a correlated Rayleigh fading channel. In particular, it is shown that a significant
performance enhancement can be made over existing admission policies through the
implementation of a novel, dynamic, load-dependent blocking threshold in conjunction
with a fixed CDMA multiple access threshold that is based on the maximum acceptable
level of MAl.Thesis (Ph.D.)-University of Natal, Durban, 1999.
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Gaffar, Mohammed Yusuf Abdul. "Subspace-based channel estimation for DS/CDMA systems exploiting pulse- shaping information." Thesis, 2003. http://hdl.handle.net/10413/4256.
Full textAbstract:
Third generation wireless systems have adopted Direct-Sequence/Code-Division Multiple-Access (DS/CDMA) as the multiple access scheme of communication. This system would typically operate in a multipath fading channel. This dissertation only deals with the task of channel estimation at the base station where the multipath delays and attenuations for each user are estimated. This information is used to aid the recovery of data that was transmitted by each user. Subspace-based algorithms are popularly used to perform the task of channel estimation because they have the desirable property of perfectly estimating the channel in a noise-free environment. In this dissertation a new subspace-based channel estimation algorithm for
DS/CDMA systems is presented. The proposed algorithm is based on the Parametric Subspace algorithm by Perros-Meilhac et al. for single-user systems. The main focus of this dissertation is to convert the Parametric Subspace algorithm from a single-user system to a multi-user DS/CDMA system. It has been shown in the literature that by using information of the pulse-shaping filter in the Channel Subspace algorithm, the variance of the channel estimates is decreased. However, this has only been applied to a single-user system. There are several subspace algorithms that have been proposed for DS/CDMA systems. Most of these algorithms sample the received
signal at the chip rate, making it impossible to exploit knowledge of the pulse-shaping filter in the channel estimation algorithm. In this dissertation a new subspace-based channel estimation algorithm is derived for a DS/CDMA system with multiple receive antennas, where the output is oversampled with respect to the chip rate. By oversampling the received signal, knowledge of the pulse-shaping filter is used in the channel estimation algorithm. It is shown that the variance of the channel estimate for the proposed subspace algorithm is less than the Torlak/Xu subspace algorithm that does not exploit information of the pulse-shaping filter. A mathematical expression of the mean square error of estimation for the new algorithm is also derived. It was shown that the analytic expression provides a good approximation of the actual MSE for high SNR. The Parametric Subspace Delay Estimation (PSDE) algorithm was developed by Perros-Meilhac et al. to estimate the multipath delays introduced by the communications channel. The limitation of the PSDE algorithm is that the performance of the algorithm deteriorates as the power of the multipath signals decrease with increasing delay time. This dissertation proposes a modified version of the PSDE algorithm, called the Modified Parametric Subspace Delay Estimation (MPSDE) algorithm, which performs better than the PSDE algorithm in an environment where the power of the multipath signals varies.
The final part of this dissertation discusses the Torlak/Xu channel estimation algorithm and the Bensley/Aazbang delay estimation algorithm. In order to compare the performance of these two subspace algorithms, the Torlak/Xu algorithm is converted to a delay estimation algorithm that is called the Parametric TX algorithm. The performance of the Bensley/Aazbang delay estimation algorithm and the proposed Parametric TX algorithm are compared and it is shown that the Parametric TX algorithm offers the better performance.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.
40
Sharma, Neeru. "Power control in multimedia CDMA cellular networks." Thesis, 2000. http://hdl.handle.net/10413/5399.
Full textAbstract:
Wireless mobile communication is witnessing a rapid growth in, and demand
for, improved technology and range of information types and services. Further,
third generation cellular networks are expected to provide mobile users with
ubiquitous wireless access to a global backbone architecture that carries a wide
variety of electronic services. We examine the topic of power control and
models that arc suitable for modem third generation wireless networks. CDMA
technology is proving to be a promising and attractive approach for spectrally
efficient, economical and high quality digital communications wireless
networks. This thesis addresses the challenge of integrating heterogeneous
transmitting sources with a broad range of Quality of Service characteristics in
the cellular COMA networks. Provided the right power control can be devised,
COMA offers the potential of extracting gain from the statistical multiplexing of
such sources. A distributed power control algorithm is proposed which is
required to update the transmitted power of the mobiles in each of the service
classes locally. and enhance the performance of the system significantly.
Algorithms for pragmatic issues like power level quantization and truncation of
power are derived and incorporated into the proposed distributed power control
algorithm.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2000.
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Wang, Qingsheng. "Power and performance trade-off in DS-CDMA receivers based on adaptive LMS-MMSE multi-user detector." Thesis, 2003. http://hdl.handle.net/10413/4212.
Full textAbstract:
Third generation cellular communication systems based on CDMA techniques have shown great scope for improvement in system capacity. Over the last decade, there has been significant interest in DS-CDMA detectors. The conventional detector, the optimal detector and a number of sub-optimal multi-user detectors (MUD) have been extensively analyzed in the literature. Recently, the reduction of power consumption in DS-CDMA systems has also become another important consideration in both system design and in implementation. In order to support wireless multimedia services, all CDMA-based systems for third generation systems have a large bandwidth and a high data rate, therefore the power consumed by the digital signal processor (DSP) is high. This thesis focuses on power consumption in the adaptive Minimum Mean Square Error (MMSE) detector which is based on the Least Mean Square (LMS) algorithm. This thesis presents a literature survey on MUD and adaptive filter algorithms. A system model of the quantized LMS-MMSE MUD is proposed and its performance is analyzed. The quantization effects in the finite precision LMS-MMSE adaptive MUD including the steady-state weight covariance, mean square error (MSE) and bit error rate (BER) versus wordlength of data and coefficient are investigated when both the data and filter coefficients are quantized. The effects of wordlength size on power consumption are investigated and the tradeoff between the power consumption and performance degradation and the optimal allocation of bits to data and to LMS coefficients under power constraint is presented.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.
42
"Distributed transmitter adaptation for wireless CDMA systems." 2003. http://library.cuhk.edu.hk/record=b6073566.
Full textAbstract:
Kin Kwong Leung."August 15, 2003."
Thesis (Ph.D.)--Chinese University of Hong Kong, 2003.
Includes bibliographical references (p. 77-[82]).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
Abstracts in English and Chinese.
43
Roopram, Kelesh D. "Design considerations and implementation of a RF front-end for CDMA adaptive array system." Thesis, 2000. http://hdl.handle.net/10413/5389.
Full textAbstract:
Recent studies have shown that considerable system capacity gains in mobile
communication systems can be obtained by exploiting the use of antenna arrays at the
base station. Unfortunately, these studies make little mention of practical issues
concerning implementation. It is thus one of the objectives of the Centre of Excellence
(CoE) in Radio Access Technologies at the University of Natal to investigate the
development of a widehand CDMA adaptive array transceiver using Alcatel software
radios as the transceiver platforms. Such a transceiver system can be subdivided into
three major sections: RF front-end, signal digitization and baseband processing stages.
Due to the enormity of such an undertaking, the research outlined in this thesis is focused
on (but not isolated to) some aspects of the RF front-end implementation for the proposed
system.
The work in this thesis can be catergorized into two sections. The first section focuses on
the theoretical and practical (or implementation) aspects of antenna arrays and
beamforming. In particular, it is evident that digital (rather than analogue) beamforming
in a multi user environment, is a more viable option from both a cost and implementation
standpoint. The second section evaluates the impact of RF component noise and local
oscillator generated phase noise in a DS-CDMA system. The implementation of a RP
front-end for a BPSK transceiver also forms part of the work in this section. LO phase
noise and Error Vector Magnitude (EVM) measurements are performed on this system to
support relevant theory. By use of the HP89410A phase noise measurement utility and
the phase noise theory developed in this thesis, a quantitative phase noise comparison
between two frequency sources used in the system were made. EVM measurement
results conclusively verified the importance of an LNA in the system. It has also been
shown that the DS-CDMA simulated system exhibits superior performance to the
implemented BPSK system. Furthermore, an EVM troubleshooting methodology is
introduced to identify possible impairments within the BPSK receiver RF front-end.
However, this thesis was written with the intention of bridging the gap between the theoretical and practical implementation aspects of RP wireless communication systems.
It is the author's opinion that this has been achieved to a certain extent.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2000.
44
Majoor, Richard James. "A MAC protocol for wireless networks with QoS guarantees." Thesis, 2002. http://hdl.handle.net/10413/4648.
Full textAbstract:
Mobile communications are becoming integrated into society at an explosive rate. While 2nd generation (2G) systems limit the user to basic services such as voice and low-bit rate data, 3G
networks are characterized by their ability to accommodate wideband multi-media traffic with Quality of Service (QoS) guarantees. In the design of a system the Medium Access Control (MAC) layer is responsible for multiplexing heterogeneous traffic onto a common transmission link and its design is critical to the overall performance of a system. A number of MAC protocols for wireless networks have been proposed in the literature - the majority having time division multiple access (TDMA) at the MAC layer. However in 3G systems there is a trend towards the use of code division multiple access (CDMA) due to its proven advantages in a
wireless environment. Although several papers on CDMA based MAC protocols have been published, virtually none of them tackle the analysis aspect of the protocols. Those papers that do perform analyses of CDMA protocols don't often consider heterogeneous traffic, and even fewer support QoS. The thesis addresses these shortcomings by proposing a MAC protocol that
supports QoS in the form of Bit Error Rate (BER) and packet delay guarantees. The thesis begins by giving an overview of proposed wireless ATM and 3G CDMA protocols and then details how power control may be used to support BER guarantees. Various Markov based analyses are presented along with Monte-Carlo Simulations. An Equilibrium Point Analysis is then performed and the work discusses how such analyses are generally infeasible for systems supporting heterogeneous traffic. After an overview of conventional scheduling algorithms the thesis proceeds to outline a novel approach by which delay guarantees may be offered using packet dropping rates as the QoS metric. Using a stochastic source model as opposed to the conventional leaky bucket traffic regulator the thesis diverges significantly from
conventional literature. The thesis also details how to calculate the probability of QoS violation and concludes with suggestions on further research avenues. As a whole the work is unique in
its approach to analyse heterogeneous traffic and the methods it uses to construct session admission zones for QoS guarantees.Thesis (Ph.D.)-University of Natal,Durban, 2002.