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Title: Adaptive modulation based MIMO systems 
Author: Gowrishankar, Ramkumar
Date: 2005
Abstract: Multiple-input multiple-output wireless links exploit the spatial dimension in a rich scattering environment by using multiple transmit and receive antennas. When combined with channel-based throughput maximizing techniques like adaptive modulation, the throughput of a MIMO link has been proven to be much larger than a conventional system. The performance of a MIMO system is highly dependent on the characteristics of the matrix channel. Proper selection of antenna weights, modulation index, data rate and transmitted power of each stream based on the channel conditions can ensure a high throughput while ensuring a minimum BER. This work proposes to design throughput-maximizing algorithms for limited feedback Open- Loop MIMO systems (systems without transmit beamforming) and Closed-Loop MIMO systems (systems with transmit beamforming) that are based on practical criterion such as BER threshold, discrete modulation indices, and channel estimation error. This work will be further extended to include interference limited multi-user MIMO systems that, in addition to the fore mentioned problems, suffer from interference between users. A Successive Interference Cancellation (SIC) based method will be developed for use in the interference limited multi-user MIMO system which will be based on the exact channel conditions instead of the channel whitening process that is currently used for such systems. The channel model used is a critical parameter that will affect the performance of MIMO systems. The SIC is also implemented as a MMSE-SIC detector for limited feedback MIMO systems and it is shown that the throughput of desired stream depends on power and modulation index of the interfering stream. The effects of channel estimation error and quantization error are evaluated for limited feedback MIMO system. Any algorithm developed must validated using realistic channel models in order to guarantee performance in a practical system. The developed algorithms will be tested under realistic channel conditions designed by Dr. Zhengquing Yun and Dr. Magdy Iskander. The contribution of this thesis is to develop novel algorithms that maximize the throughput for practical MIMO systems. Adaptive modulation based power and stream control methods will be developed to maximize the throughput of both single link and interference-limited multi user MIMO system .
Description: Thesis (M.S.)--University of Hawaii at Manoa, 2005. Includes bibliographical references (leaves 74-75). xi, 75 leaves, bound ill. 29 cm
URI: http://hdl.handle.net/10125/20544
Rights: All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Keywords: MIMO systems

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