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 201 for “"CDMA"”.
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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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Beamforming for MC-CDMA
… to 10Mbps. A variation of OFDM is Multi-Carrier CDMA (MC-CDMA) which is an OFDM technique where the individual data symbols are spread using a spreading code in the frequency domain. The spreading code associated with MC-CDMA provides multiple access technique as well as interference suppression. …
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2GHz W-CDMA Radio Transceiver
… transceiver has been designed and built for a W-CDMA experimental system operating at 2GHz. The radio is an RF front-end for mobile terminals. The radio provides the functions of modulation and demodulation to enable transmitting and receiving digital information through the air link. The radio …
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Practical multiuser detection algorithms for CDMA
… that are based on code division multiple access (CDMA) technologies. These include the adaptive receiver and the interference canceller. The overall complexity of implementing them is examined. The effects of the proposed algorithms on reducing of multiple access interference (MAI) and their …
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Capacidad en sistemas celulares W-CDMA
… un análisis de capacidad de sistemas celulares W-CDMA. El estudio considera la interfaz radio, y supone la utilización de detección monousuario basada en receptores Rake. El análisis se centra en los aspectos de control de potencia y asignación celular, y se basa en unos modelos adecuados de …
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Simulation of Third Generation CDMA Systems
… a Wideband Code Division Multiple Access (WCDMA) air interface with the fixed network of Global System for Mobile communications (GSM). In this thesis a signal simulator was implemented according to the physical layer specification of the IMT-2000 WCDMA system. The data is transmitted in a …
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Selective cancellation of interference for CDMA
… reverse link in a Code Division Multiple Access (CDMA) cellular system. However, it has beep observed that indiscriminate cancellation of all received signals can degrade performance. This thesis explores the use of selective cancellation to improve the performance of practical CDMA systems. …
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Energy-Efficient Multicarrier and Multicarrier-CDMA Systems
… Multicarrier-Code Division Multiple Access (MC-CDMA) systems are considered. Specifically, Multicarrier Modulation (MCM) such as Orthogonal Frequency Division Multiplexing (OFDM) is used in these systems with emphasis on energy efficiency. These systems are examined for their performances over …
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Performance of CDMA power control for HAPS
… area. Wideband code division multiple access (WCDMA) has emerged as the mainstream air interface solution for 3G networks. Also the ITU has specifically authorized the use of some IMT-2000 (3G) frequency bands from HAPS. This project addresses downlink and uplink power control for high altitude …
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Interference suppression and diversity for CDMA systems
In code-division multiple-access (CDMA) systems, due to non-orthogonality of the spreading codes and multipath channels, the desired signal suffers interference from other users. Signal fading due to multipath propagation is another source of impairment in wireless CDMA systems, often severely …
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Data Chunking in Quasi-synchronous DS-CDMA
<p>DS-CDMA is a popular multiple access technique used in many mobile networks to efficiently share channel resources between users in a cell. Synchronization between users maximizes the user capacity of these systems. However, it is difficult to perfectly synchronize users in the reverse link due …
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A hybrid frequency modulated CDMA communication system
… advantages of a Code Division Multiple Access (CDMA) system. This system aims to provide WLL telephone services at low cost, with wireline grade voice quality, fast infrastructure deployment and ease of planning. In this thesis, a theory for FM/CDMA system performance is established. Closed form …
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Receiver-Assigned CDMA in Wireless Sensor Networks
… Code Division Multiple Access (RA-CDMA) physical (PHY) layer multiple access technique, which may enable higher network scalability while maintaining performance and contributing additional robustness. This thesis presents a comparison of the contention mechanisms of IEEE 802.15.4 …
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Receiver Implementations for a CDMA Cellular System
… is a 1.25 MHz Code Division Multiple Access (CDMA) system (IS-95). In CDMA systems, multiple access interference limits the capacity of any system using conventional single user correlation or matched filter receivers. Previous research has shown that multiuser detection receivers that employ …
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A multistage RAKE receiver for CDMA systems
… base station of a Code Division Multiple Access (CDMA) cellular communications system. This receiver combines the interference rejection capability of multiuser receivers with the robust performance of a RAKE receiver in the presence of multipath interference. Unlike previous multiuser receiver …
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Fast blind adaptive equalisation for multiuser CDMA systems
… communication over a dispersive channel in a CDMA system, we have to re-establish the orthogonally of codes which are used when combining input signals from many users onto a single communication path, as otherwise the performance of such system is limited significantly by inter-symbol …
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Partial DS-CDMA for mobile satellite data networks.
… sequence code division multiple access (DS-CDMA) is used, this need not to be the case, because the DS-CDMA system allows many packets to coexist in a given slot. Thus packets are correctly received with certain probability which depends on the simultaneous number of packets in the slot. …
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MULTI-CHANNEL CDMA-LIKE CAPACITIVE SENSOR INTERFACE CIRCUITS
… wireless connections. This thesis introduces a CDMA-like period modulation multi-capacitive-sensor interface circuit, which targets at the IoT applications. The proposed architecture can simultaneously read in 16 capacitive sensors and provide the combined 16 digitized output in one sample. By …
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CAPACITY ENHANCEMENT OF CDMA SYSTEM USING ANTENNA ARRAY
… for a multirate code-division multiple access (CDMA) system with uniform linear array (ULA) at the base station (BS) [1 - 3]. An overall system outage probability is proposed as a capacity performance measure for multirate CDMA system with different service requirements among users. In this …
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Relay Diversity Techniques for OFDM and MC-CDMA
… cyclic delay diversity (RCDD) for OFDM and MC-CDMA<br/>systems. The performance analysis of the wireless relay networks under<br/>dierent protocols and fading channels are investigated. We derived<br/>the formulas for the symbol error rate (SER) of the investigated<br/>schemes in fading …
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