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Fixed-Point Implementation of a Multistage ReceiverCameron, Rick A. 13 January 1997 (has links)
This dissertation provides a study of synchronization and quantization issues in implementing a multistage receiver in fixed-point Digital Signal Processing (DSP) hardware. Current multistage receiver analysis has neglected the effects of synchronization and quantization; however, these effects can degrade system performance and therefore decrease overall system capacity. The first objective is to analyze and simulate various effects of synchronization in a multistage system. These effects include the effect of unsynchronized users on the bit error rate (BER) of synchronized users, and determining whether interference cancellation can be used to improve the synchronization time. This information is used to determine whether synchronization will limit overall system capacity. Both analytical and simulation techniques are presented. The second objective is to study the effects of quantization on the performance of the multistage receiver. A DSP implementation of a practical receiver will require a DSP chip with a fewer number of bits than the computer chips typically used in simulation of receiver performance. Therefore, the DSP implementation performs poorer than the simulation results predict. In addition, a fixed-point implementation is often favored over a floating-point implementation, due to the high processing requirements necessitated by the high chip rate. This further degrades performance because of the limited dynamic range available with fixed-point arithmetic. The performance of the receiver using a fixed-point implementation is analyzed and simulated.
We also relate these topics to other important issues in the hardware implementation of multistage receivers, including the effects of frequency offsets at the receiver and developing a multiuser air protocol interface (API). This dissertation represents a contribution to the ongoing hardware development effort in multistage receivers at Virginia Tech. / Ph. D.
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Performance Analysis of MC-CDMA and CI/MC-CDMA Using Interference Cancellation TechniquesSHARMA, ANSHUL 19 September 2008 (has links)
No description available.
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Frequency Generalized MC-CDMA Systems and Performance over Multiband Channels and with Multiple Level Orthogonal (MLO) CodesZhang, Jingtao January 2010 (has links)
No description available.
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DISTRIBUTED TERRESTRIAL RADIOLOCATION USING THE RLS ALGORITHMBrown, Andrew P., Iltis, Ronald A. 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / This paper presents the development of two distributed terrestrial radiolocation algorithms that use
range estimates derived from DS-CDMA waveforms. The first algorithm, which is RLS-based, is
derived as the solution of an approximate least-squares positioning problem. This algorithm has the
advantage of reduced computational complexity, compared with the EKF-based algorithm that is
presented. It is shown via simulations that both positioning algorithms perform well, with the
performance of the EKF-based algorithm being superior.
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Localization Using CDMA-MIMO RadarIltis, Ronald A. 10 1900 (has links)
ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / A MIMO radar system for target localization is presented which uses direct-sequence CDMA (DS-CDMA) waveforms. The received DS-CDMA signal at each antenna is expressed directly in terms of the target positions. The waveforms employed are Gold sequences, and hence are not exactly orthogonal. A generalized successive interference cancellation (GSIC) approach is used to resolve multiple scatterers and reduce clutter. Simulation results are presented which suggest the capability to detect weak scatterers in the presence of clutter using the cancellation method.
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Expectation-Maximization and Successive Interference Cancellation Algorithms For Separable SignalsIltis, Ronald A., Kim, Sunwoo 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The expectation-maximization (EM) algorithm is well established as a computationally efficient
method for separable signal parameter estimation. Here, a new geometric derivation and
interpretation of the EM algorithm is given that facilitates the understanding of its convergence
properties. Geometric considerations then lead to an alternative separable signal parameter estimator
based on successive cancellation. The new Generalized Successive Interference Cancellation
(GSIC) algorithm may offer better performance than EM in the presence of large signal power
disparities. Finally, application of the GSIC algorithm to CDMA-based radiolocation is discussed,
and simulation results are presented.
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CDMA SATELLITE MOBILE COMMUNICATION SYSTEM MULTI-SIGNAL RECEIVING AND SOFTWARE IMPLEMENTATIONHao, Wu, Zhibin, Zheng 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper presents one new type CDMA multi-signal receiving protocol, which is suitable for satellite
mobile communication systems. Then it gives the principle analysis and describes the realization of
this protocol. Meanwhile, it gives the software protocol implementation scheme. From the long point
of view, it will more increase the system flexibility, which is easier to update; and will solve the
interoperability and integration application problems. Finally, the simulation results conclude that
software implementation of CDMA multi-signal receiving in satellite mobile communication system
is feasible, and it may be used in other wireless communication systems.
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Evaluation of fourth generation air-interfaces for mobile communicationsVan den Bergh, Ryan Michael 29 May 2008 (has links)
Abstract
Development of the Fourth Generation of mobile communication systems, or 4G, has already
begun in various organizations and research institutions worldwide. There is currently
no single conclusive definition for 4G systems, and the process of 4G standardization will
only begin after the World Radiocommunication Conference in 2007. The purpose of this
report is to provide an objective definition of 4G systems based on user requirements, and
to use this definition to determine an appropriate 4G access network architecture.
By examining the current trends in user requirements, and the methodologies proposed by
different researchers, an objective definition of 4G systems was developed. The definition
states that the purpose of 4G systems is to provide users with the capacity to access any
service at any time at a reasonable cost and at the required levels of quality. There are
two developmental methodologies which are currently being considered to achieve this objective:
first the evolution and convergence of existing systems, including cellular, IT and
broadcasting communication systems, and second, the development of a new 4G access
network capable of providing users with access to advanced services. The primary specification
for this new access network is that it must provide a throughput of 1 Mbps for mobile
users and 1 Gbps for users that are stationary. Other requirements include high spectral
efficiency and high capacity and coverage.
The primary focus of this report is the examination of the second of the above methodologies
by evaluating the performance of candidate 4G air-interface architectures so that a
recommendation could be made as to which of the architectures is the preferred choice as the
core component in a new 4G access network. Orthogonal Frequency Division Multiplexing
(OFDM) modulation is a high performance modulation technique capable of achieving high
levels of spectral efficiency and is widely accepted as the technique most capable of meeting
4G access network requirements. There are two primary access network architectures that
make use of OFDM modulation and could form the core components of a 4G air-interface,
the physical component of a 4G access network. To determine which architecture is the
appropriate choice for 4G systems, a series of simulations were run using realistic models
of a wireless environment. The results of those simulations were analyzed, and it was
determined that, due to the absence of multiple access interference found in MC-CDMA,
OFDMA systems better met the defined requirements for a 4G air-interface. The use of
additional techniques such as radio resource management, multi-antennae technologies and
software defined radios are cited as potential methods for improving both OFDMA and
MC-CDMA performance.
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Diseño de una red rural para el Valle de Cañete, basado en tecnología CDMA450Rodríguez Alfaro, Gino Luis 09 June 2011 (has links)
El presente trabajo consiste en diseñar una red rural de telecomunicaciones con
tecnología CDMA en 450 MHz, que pueda brindar servicio a los distritos de
Pacarán, Zúñiga, Catahuasi, Tupe, Chocos, Huangascar, Manden, Viñac,
ubicados a orillas del rio Cañete y sus alrededores.
En el primer capítulo se muestra el estudio de la tecnología celular CDMA 2000
en frecuencias de 450 MHz, sus características y ventajas favorables para la
aplicación en redes rurales. También se describe las características adversas
en zonas rurales y la situación normativa actual en este escenario.
El segundo capítulo muestra la información obtenida del estudio en sitio de la
zona donde se pretende dar cobertura de voz y datos. Con dicha información y
datos estadísticos del Instituto Nacional de Estadística e Informática (INEI), se
realizan estimaciones y cálculos para obtener la demanda potencial.
En el tercer capítulo se realiza el diseño la de red rural, plasmando la topología
de red en el valle de cañete. Luego mediante la estimación realizada en el
capitulo anterior, dimensionamos la capacidad de los equipos en la red,
asegurando la cobertura de la zona y el escalamiento de la red en el futuro;
basado en estos requerimientos se presenta el equipamiento elegido.
En el último capítulo se detalla los costos de inversión inicial de los activos y
servicios necesarios de mayor importancia para iniciar las operaciones de red.
También se muestra los costos de operación más importantes.
Por último, luego de adquirir en el presente trabajo nuevos conocimientos e
interiorizar la problemática de la zona rural del Valle de Cañete, se presentan
conclusiones y recomendaciones. / Tesis
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Performance analysis and control of wireless communication networks with multi-user receivers /Catrein, Daniel. January 2007 (has links)
Zugl.: Aachen, Techn. Hochsch., Diss., 2007.
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