报告人：Professor   Julian Cheng

时  间：2013年5月9日（周四）上午10:00

地  点：崂山校区明德楼338教室

Abstract:

 The performance of free-space optical communication systems is compromised by atmospheric fading and pointing error effects. The pointing error effect is widely considered as combination of two components: boresight error and jitter error. A statistical model is investigated for pointing error with nonzero boresight error by taking into account of laser beamwidth, detector aperture size, and jitter variance. A novel closed-form probability density function (PDF) is derived for the generalized pointing error model. Furthermore, we obtain closed-form PDF and series PDF, respectively, for the composite lognormal and Gamma-Gamma turbulence channels with nonzero boresight pointing errors. We conduct error rate analysis of on-off keying signaling with intensity modulation and direct detection over the lognormal and Gamma-Gamma fading channels. The bit-error rate results are presented in highly accurate converging series. Asymptotic error rate analysis and outage probability of such a system are also presented based on the derived composite PDFs. It is shown that the boresight error can only affect the coding gain, while the diversity order is determined by either the atmospheric fading effect or the pointing error effect, depending on which effect is more dominant.

Speaker Bio:

Julian Cheng received the B. Eng. Degree (First Class) in electrical engineering from the University of Victoria, Victoria, BC, Canada in 1995, the M.Sc. (Eng.) degree in mathematics and engineering from Queen’s University, Kingston, ON, Canada in 1997, and the PhD degree in electrical engineering from the University of Alberta, Edmonton, AB, Canada, in 2003.

He is currently an Associate Professor in the School of Engineering, Faculty of Applied Science, at The University of British Columbia, Okanagan campus. Previously, Dr. Cheng worked for Bell Northern Research (BNR) and Northern Telecom (later known as NORTEL Networks), and taught at both University of Alberta and Lakehead University. His current research interests include digital communications over wireless channels, orthogonal frequency division multiplexing, spread spectrum communications, statistical signal processing for wireless applications, and optical wireless communications.