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Degree

Doctor of Engineering, Cleveland State University, Fenn College of Engineering, 2011.

Abstract

Two new energy detection (ED) Ultra-Wideband (UWB) systems are proposed in this dissertation. The first one is an ED UWB system based on pulse width modulation (PWM). The bit error rate (BER) performance of this ED PWM system is slightly worse than ED pulse position modulation (PPM) system in additive white Gaussian noise (AWGN) channels. However, the BER performance of this ED PWM system surpasses that of a PPM system in multipath channels since a PWM system does not suffer cross-modulation interference (CMI) as a PPM system. In the presence of synchronization errors, the BER performance of a PWM system also surpasses that of a PPM system. The second proposed ED UWB system is based on using two pulses, which are the different-order derivatives of the Gaussian pulse, to transmitted bit 0 or 1. These pulses are appropriately chosen to separate their spectra in frequency domain. The receiver is composed of two energy detection branches and each branch has a filter which captures the signal energy of either bit 0 or 1. The outputs of two branches are subtracted from each other to generate the decision statistic and the value of this statistic is compared to a threshold to determine the transmitted bits. This system is named as acf{GFSK} system in this dissertation and it exhibits the same BER performance as a PPM system in AWGN channels. In multipath channels, a GFSK system surpasses a PPM system because it does not suffer CMI. And the BER performance of a GFSK system is better than a PPM system in the presence of synchronization errors. When a GFSK system is compared to a PWM system, it will always achieve approximately 2 dB improvement in AWGN channels, multipath channels, and in the presence synchronization errors. However, a PWM system uses lower-order derivatives of the Gaussian pulse to transmit signal, and this leads to a simple pulse generator. In this dissertation, an optimal threshold is applied to improve PPM system performance. The research results show that the application of an optimal threshold can effectively mitigate the effect of CMI and synchronization errors and achieve performance improvement. Finally, the multiple access schemes are discussed and time hopping is chosen as the multiple access scheme for PWM and GFSK systems.

Subject Headings

Electrical Engineering

Keywords

Ultra-wideband communications (UWB)

Committee / Advisors

Fuqin Xiong (Committee Chair)
Dr. Ching Chang (Committee Member)
Dr. Pong Chu (Committee Member)
Dr. Murad Hizlan (Committee Member)
Dr. Chansu Yu (Committee Member)
Wenbing Zhao, Dr. (Committee Member)

Pages

174p.

Document number: csu1323224057
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=csu1323224057

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