"Time Reversal Signal Processing: Applications in Radar, Biomedicine, and Wireless Communications"

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In the past few decades, array processing technology has proven to be one of the most active research subjects evolving itself from aerospace applications to many other dimensions including: sensor networks for surveillance; microphone and seismic arrays to localize objects of interest; mobile phones to locate phone users (a recent US FCC E911 emergency requirement), and; smart antennas to improve communication systems' performance. This research focuses on improving the current state-of-the-art in array processing in particular in the detection and accurate estimation of the locations of passive targets embedded in highly complex environments with strong interference and noise. Applications of interest include biomedicine (breast cancer detection), radar/sonar systems (target localization and tracking), and wireless communications (improved transmitter/ receiver design for enhanced system performance). In traditional array processing, a small number of antenna elements, collectively referred to as the transmit array, probe the environment. The waves scattered or reflected by different sections of the environment are recorded at the receive array and are processed for the desired physical parameter(s) related to the probed environment. A common phenomena in traditional array processing that significantly degrades the system's performance is multiple target reflections reaching the receive array through differnt paths. Consequently, most traditional techniques attempt to compensate for the effect of multiple scattering (multipath). In this research, I take a different approach and address the question of what can be gained if an array processing algorithm explores the additional information existing in the temporal structure of the observed fields (i.e., in the set of multipath delays) to its advantage. My approach is based on time reversal (TR) used to develop new TR based array processing algorithms for practical source localization applications in radar and sonar systems, biomedicine, and wireless communications. My TR algorithms makes positive use of multipath to achieve high resolution and superior performance up to a gain of 5dB over the existing state-of-the-art in array processing.