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Title: Nonlinear Distortion Mitigation in Dynamic-range-limited Optical Wireless Communication System
Committee:
Dr. Tong Zhou, ECE, Chair , Advisor
Dr. Gee-Kung Chang, ECE
Dr. Xiaoli Ma, ECE
Dr. John Barry, ECE
Dr. Yao Xie, ISyE
Dr. Robert Baxley, GTRI, Co-Advisor
Abstract:
The objective of this dissertation is to mitigate the nonlinear distortion in dynamic-range-limited optical wireless communication (OWC) systems. The nonlinearity in an OWC system can be treated as a family of dynamic-range-limited nonlinearities. To overcome nonlinearities, we can deal with either the signal or the system. One straightforward approach is to choose or modify input signals such that they are insensitive to the nonlinear distortions. Another approach is to compensate for the nonlinearities by predistortion or postdistortion. In the preliminary research, we analyze how to maximize the signal-to-noise-plus-distortion ratio (SNDR) of the nonlinearities in OWC systems. The result herein can serve as a guideline to design predistortion linearization of nonlinear devices like LEDs. Additionally, we study the constrained clipping method which can mitigate the distortions so that the clipping levels can be more aggressive than the simple clipping to further reduce the peak-to-average power ratio (PAPR) for orthogonal frequency division multiplexing (OFDM) signals. In the follow-up research, we extend our work to multiple-input multiple-output (MIMO) OWC systems and bit-loaded OFDM systems.
