Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 122 for “"Code division multiple access."”.
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Molecular Code Division Multiple Access: Gaussian Mixture Modeling
… detection technique along with a molecular-based access method, are proposed in here for communication between asynchronous users. In this work, the received molecular signal is modeled as a Gaussian mixture distribution when the MC system undergoes Brownian noise and inter-symbol interference …
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Cooperative diversity aided direct-sequence code-division multiple-access systems
In relay-assisted direct-sequence code-division multiple-access (DS-CDMA) systems, the distance between the relay and the destination receiver may be significantly shorter than that between the source transmitter and the destination receiver. Therefore, the transmission power of the relay may be …
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Assignment of Spreading Codes in Code Division Multiple Access Radio Systems
This thesis is concerned with spreading code construction and assignment in Direct Sequence Code Division Multiple Access radio systems. Particular emphasis is given to Quasi-Synchronous Code Division Multiple Access. The frequency spectrum required for these systems depends on the length of the …
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Capacity improvements for a direct-sequence code division multiple access network
… which enhance the capacity of a Direct-Sequence Code-Division-Multiple-Access (DS-CDMA) mobile telephone network. The capacity of both Private Mobile Radio (PMR) and cellular networks are derived and the many techniques which are currently available are reviewed. Areas which may be further …
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Performance of Hyperbolic Position Location Techniques for Code Division Multiple Access
… the mobile unit. In recent years, the IS-95 Code Division Multiple Access (CDMA) system has gained increasing popularity in North America because of the many advantages it offers over existing air interfaces. However, CDMA systems present some unique challenges to the effectiveness of …
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Evolution of loosely synchronized spreading codes in code-division multiple-access systems
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. …
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A Code Division Multiple Access Communication System for the Low Frequency Band
In this thesis, a code division multiple access (CDMA) communication system for the low frequency (LF) channel is proposed, discussed and analyzed. This LF/CDMA scheme is similar to classical CDMA schemes in that K users share a channel by phase modulating their transmissions with signature …
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Application of smart antennas to wideband code division multiple access : the uplink performance
… antenna arrays for the uplink of a Wideband Code Division Multiple Access (WCDMA) system in the Frequency Division Duplex (FDD) mode is addressed in this thesis. The beam-forming is implemented with a LS - DRMTA algorithm and a Lagrange multiplier based algorithm using the Q channel only. The …
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Maximum likelihood detection for probabilistic models of optical code division multiple access channels
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.
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Effects of Cross-Correlation Interference on an Optical Code Division Multiple Access Communication System
… on the error rate performance of an optical code division multiple access communication system are investigated. The system model is a multiaccess satellite repeater in which user separation is accomplished by direct sequence modulation. The analysis is for direct detection, optical …
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Performance analysis of star architecture packet-switched VSAT networks using random code division multiple access
… research is to provide a performance analysis of multiple access protocols in packet-switched Very Small Aperture Terminal (VSAT) satellite communication networks. This research consisted of three major thrusts. First, we analyzed the average time delay of the broadcast Time Division Multiplexing …
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Dark signalling and code division multiple access in an optical fibre LAN with a bus topology
… fibre network that uses a bus topology and Code Division Multiple Access (CDMA). Various potential configurations are analysed and compared and it is shown that a serious limitation of optical CDMA schemes using incoherent correlators is the effect of optical beating due to the presence of …
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Applications of superstructure fibre Bragg gratings for optical code division multiple access and packet switched networks
… research on the implementation of all-optical code generation and recognition based on superstructure fibre Bragg grating (SSFBG) for use in Optical Code Division Multiple Access (OCDMA) systems and also in high-speed all-optical packet switched networks.These results highlight the precision …
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Development and Analysis of Adaptive Interference Rejection Techniques for Direct Sequence Code Division Multiple Access Systems
… inadequacy of conventional CDMA receivers in a multiple access interference-limited mobile radio environment has spurred research on advanced receiver technologies. This research investigates the use of adaptive receivers for single user demodulation to overcome some of the deficiencies of a …
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Design and analysis of high-speed optical correlators for multiwavelength optical header recognition and optical code division multiple access
Optical correlators arc attractive elements for packet-switched optical networks because they enable the headers of high-speed optical packets to be processed and recognised "on-the-fly", thus, switching the packets to different destinations without the need for optical-to-electrical and …
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Investigation of code reconfigurable fibre Bragg gratings for Optical Code Division Multiple Access (OCDMA) and Optical Packet Switching (OPS) Networks
… Research Centre, towards the implementation of code reconfigurable OCDMA and all-optical packet switching nodes based on fibre Bragg grating (FBG) technology. My research work involves characterizing the performance of various gratings, specifically high reflectivity, short chip duration, long …
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Simulation of an Anti-Collision Algorithm for RFID Systems using a Code Division Multiple Access with Adaptive Interference Cancellation (CDMA/AIC) Approach with Dynamic Processing Gain (Gp)
… is limited by collision problems when multiple tags transmit simultaneously. Due to the collision problem, much research has been developed using anti-collision algorithms to enhance the systems' efficiency, save energy, and ensure the correct transmission of information. Most research …
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High performance multi-carrier technologies with expanded applicability to CDMA systems (DS-CDMA and MC-CDMA)
Code division multiple access (CDMA) has been an important component in wireless communication systems since the early 1980’s. Now the frontrunner in the 3G cellular standard, CDMA techniques have come a long way since their inception. However, these systems are not without their limitations -- …
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