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 30 for “"Multipath channels"”.
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Communication through noisy, random-multipath channels
Thesis (Sc.D.) Massachusetts Institute of Technology. Dept. of Electrical Engineering, 1956.
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Performance analysis of CDMA systems in multipath channels
… Two benefits of CDMA include resistance to multipath fading and graceful performance degradation in the presence of multiple access interference. These benefits have made CDMA especially attractive for cellular telephone systems and other wireless networks. This thesis project is divided …
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Experimental Investigation Of Ultrawideband Wireless Systems: Waveform Generation, Propagation Estimation, And Dispersion Compensation
… research. One key challenge is the increased multipath dispersion which results because of the fine temporal resolution. The received response consists of different components, which have certain delays and attenuations due to the paths they took in their propagation from the transmitter to …
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Adaptive Arrays and Diversity Antenna Configurations for Handheld Wireless Communication Terminals
… the 99% reliability level in non line-of-sight multipath channels. Thus, peer-to-peer systems of handheld transceivers that use antenna arrays can achieve reliability comparable to systems of single-antenna handheld units, with only one-fifth the transmitter power, resulting in lower overall …
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OWSS And MIMO-STC-OFDM: Signaling Systems for the Next Generation of High Speed Wireless LANs
… performance and high spectral efficiency in multipath channels. This dissertation also presents a novel MIMO-STC-OFDM system which targets data rates in excess of 100 Mbps and at the same time achieve both high spectral efficiency and high performance. Simulation results validate the superior …
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Design and verification of SC-FDE/OFDM communication schemes for millimetre-wave wireless system using FPGA technologies
… were designed and implemented to mitigate the multipath fading of the 60 GHz indoor channels. As a result, a complete millimetre-wave transceiver operating at 64.8 GHz, with up to 100 Mb/s data-rate utilizing 16-QAM modulation scheme is realized.<br/><br/>The re-programmability offered by …
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Optimization methods for active and passive localization
… localization of radio frequency sources over multipath channels is a difficult problem arising in applications such as outdoor or indoor geolocation. Common approaches that combine ad-hoc methods for multipath mitigation with indirect localization relying on intermediary parameters such as …
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An Examination into the Statistics of the Singular Vectors for the Multi-User MIMO Wireless Channel
… in multiple-input-multipleoutput (MIMO) wireless channels make use of the singular value decomposition (SVD) of the channel matrix. For the multi-user case, the SVD of the channel matrix for each user may result in right and left singular vectors that are similar between users. This proposes …
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Receiver Implementations for a CDMA Cellular System
… with conventional and multiuser receivers in multipath channels and when near-far conditions exist. Simulation results present the robustness of multiuser receivers to near-far in a practical system. In addition to multiuser implemenations, quantization effects from finite bit analog to …
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Sparse equalizer filter design for multi-path channels
… equalizers are designed for sparse multi-path channels under a pre-defined Mean Squared Error (MSE) constraint. We start by examining the intrinsic sparsity of the Zero Forcing equalizers and the FIR Minimum MSE (MMSE) equalizers. Next the equalization MSE is formulated as a quadratic function …
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Low computational complexity bit error rate simulation for personal communications systems in multipath and fading environments
… in simulation times for digital systems on multipath channels. The simulations are carried out for randomly generated data as well as coded voice data. The data is then processed according to the standard selected (IS-54 TDMA or IS-95 CDMA.) The coded bits are transmitted over a simulated …
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Development and Analysis of Adaptive Interference Rejection Techniques for Direct Sequence Code Division Multiple Access Systems
… The limitation of existing blind algorithms in multipath channels is analyzed and a new blind algorithm is proposed that overcomes this limitation. The optimal receiver structure for multi-rate spread spectrum systems is derived and the performance of this receiver in various propagation …
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Blind Channel Estimation and Multiuser Detection for Multi-Rate CDMA Communications
… dual-rate systems over frequency-selective multipath channels are developed. In the context of multicarrier DS/CDMA, based on a finite-length truncation approximation on the band-limited chip waveform, blind timing acquisition and channel estimation scheme is proposed for multi-rate systems. …
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Four Branch Diversity Combining and Adaptive Beamforming Measurements Using Mobile Arrays at 2.05 GHz
… and adaptive beamforming techniques overcome multipath fading, improve coverage, and increase capacity in wireless communications systems. In this thesis, diversity combining and adaptive beamforming performance of different four element arrays for mobile (vehicular speed) and portable …
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Advances in Iterative Probabilistic Processing for Communication Receivers
… are (1) joint synchronization and detection in multipath channels with emphasis on frame timing, (2) detection in co-channel interference and non-Gaussian noise, and (3) joint channel estimation and multi-signal detection. This dissertation presents the advances we have made in iterative …
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Adaptive antenna systems for mobile broadband communications
… wireless communications, and characterizes the multipath fading channels of mobile broadband systems. In particular, we consider antenna systems for the base station, as well as multiple-input multiple-output systems where antenna systems are utilized at both the base station and the mobile …
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Interference suppression and diversity for CDMA systems
… 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 impacting performance. In this dissertation, …
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Intercarrier Interference Suppression for the OFDM Systems in Time-Varying Multipath Fading Channels
… its spectral efficiency and robustness over the multipath channels, orthogonal frequency division multiplexing (OFDM) has served as one of the major modulation schemes for the modern communication systems. In the future, the wireless OFDM systems are expected to operate at high …
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Ultra-wideband technology for short-range wireless communication
… over additive white Gaussian noise (AWGN) and multipath channels. Starting from the known capacity of M-ary modulated signals, the computation of UWB capacity over the AWGN channel takes into account UWB specific constraints. The constraints are the power spectrum density limitation under …
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Underwater communication via particle velocity channels : principles, channel models, and system design
… and equalization in underwater particle velocity channels using acoustic vector sensors was developed. System equations for such a receiver were derived and channel equalization using these sensors was formulated. A multiuser system using vector sensors and space time block codes was also …
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