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Browsing by Author "Petrus, Paul"

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    Blind adaptive antenna arrays for mobile communications
    Petrus, Paul (Virginia Tech, 1994)
    Adaptive antenna arrays have tremendous potential for increasing the capacity of mobile communications, by reducing co-channel interference, multipath, and noise. Blind adaptive algorithms, that is, algorithms which do not require a training sequence, are investigated and compared in this study. These algorithms are tested for common cellular signals. The performances of three blind adaptive algorithms: the Constant Modulus Algorithm (CMA), the Spectral self-COherence Restoral Algorithm (SCORE), and the spectral correlation predictor using a Time-Dependent Adaptive Array (TDAA), are studied. The TDAA is introduced as a new blind algorithm that exploits the cyclostationary property of the signal. Results show that the TDAA is able to out-perform the other blind algorithms for most of the test conditions and provides the optimal MSE solution.
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    Novel Adaptive Array Algorithms and Their Impact on Cellular System Capacity
    Petrus, Paul (Virginia Tech, 1997-03-18)
    This report focuses on the application of adaptive arrays to the Advanced Mobile Phone Service (AMPS) and Code Division Multiple Access (CDMA) cellular systems. Adaptive arrays have been proposed as early as in the 1960s to improve the signal quality, but most of its applications were restricted to defense purposes. Recently, there has been a surge in interest of applying adaptive arrays for cellular systems. This work introduces new blind adaptive array algorithms for AMPS and CDMA signals. The theoretical capacity limit using an adaptive array at the base station for an AMPS cellular system is derived in this work. One of the significant contributions in this research is a macrocell channel model which provides angle-of-arrival (AOA) statistics of the multipath components. Practical issues involved in the implementation of an adaptive array are addressed and the author's implementation of an 8-element adaptive array operating at 2.05 GHz is explained. This research also analyzes the capacity that can be o ered by an adaptive array in a system where CDMA users co-exist with existing AMPS users. A novel cellular CDMA system which exploits adaptive arrays is introduced and the capacity o ered by this system is compared with existing and other systems exploiting spatial dimension.