2007

Professor Chintha Tellambura

Bensted Lecture Title

Precoder design and power control using convex and non-convex optimization techniques

Thursday, August 16, 2007 @ 14:30 ? 15:30 p.m.
Applied Science Bldg., Room 9896

Abstract

Global optimization has provided both an insightful modeling language and a powerful solution tool to the analysis and design of communication systems over the last decade. In this talk, I will present two specific global optimization formulations.

The first part of this talk provides a convex optimization approach to the precoder design problem in MIMO systems employing Orthogonal Space-Time Block Codes (OSTBCs). A general precoder design framework is developed for OSTBC-based MIMO wireless systems to exploit the partial channel state information (CSI) on both transmits and receive correlations. The precoder is designed for minimizing the exact symbol error rate (SER) and is formulated as a convex optimization problem that can be efficiently solved using modern optimization techniques. Our proposed design is applicable for various antennas configurations and modulation constellations. Moreover, we show that for some particular correlation models, computationally simple closed-form precoders can be developed.

Convex optimization in communications systems has long been an active research area. However, nonconvex optimization problems usually arise naturally when formulating real-world problems.

The second part of this talk presents a new approach to nonconvex optimization problems. One of such problems is the power control problem in wireless networks in order to optimize the transmission subject to quality of service (QoS) constraints. It has been shown earlier that the power control problem in the wireless cellular network framework can be efficiently solved using the so-called geometric programming. However, in order to enable the application of geometric programming the signal to interference ratio (SIR) has been considered instead of SINR. Such change of the original problem formulation is obviously imprecise and might be very loose because it does not take into account the noise component, especially for low SNR operation. In this work, we show that the power control problem for wireless cellular systems can be efficiently solved via the so-called difference of two convex functions (D.C.) programming.

Biography

Chintha Tellambura received his PhD in Electronics Engineering in 1993 from the University of Victoria in British Columbia. From 2002, he has been with the Department of Electrical and Computer Engineering at the University of Alberta, where he is a Professor. His research interests include MIMO, OFDM, and wireless communication theory, and he has published about 100 refereed journal papers.

2006

Prof. P.Y. Kam

Department of Electrical and Computer Engineering
National University of Singapore
Singapore

Bensted Lecture Title

Frequency Estimation and its Applications in Wireless Communications

Research Interests

• Communication theory
• Detection and estimation
• Signal processing
• Stochastic processes

Prof. Pooi Yuen Kam was born in Ipoh, Malaysia, in 1951, and received the B.S, M.S., and Ph.D. degrees in electrical engineering in 1972, 1973, and 1976, respectively, all from the Massachusetts Institute of Technology, Cambridge. From 1976 to 1978, he was a Member of the Technical Staff, Bell Telephone Laboratories, Holmdel, NJ, where he was engaged in packet network studies. Since 1978, he has been with the Department of Electrical and Computer Engineering, National University of Singapore, where he is now a Professor. His research interests are in detection and estimation theory, and its applications to digital communications and coding. Since 1996, he has been the Editor for Modulation and Detection for Wireless Systems of the IEEE Transactions on Communications. He won the Best Paper Award at IEEE VTC 2004 Fall.

2005

Prof. Ross D. Murch

Department of Electronic and Computer Engineering
Hong Kong University of Science and Technology
Clearwater Bay
Hong Kong

Bensted Lecture Title

Cross-Layer Optimization for Multiuser MIMO Wireless Communications

Research Interests

• Wireless communication systems
• MIMO antenna systems
• UWB, WLAN
• Cross-layer design

Professor Murch completed his PhD in 1990 in Electrical and Electronic Engineering at the University of Canterbury, New Zealand. Since 1992, he has been with HKUST. He has research interests in wireless communication systems including high speed wireless communication using MIMO signal processing and novel antenna technology. He has several US patents related to wireless communication, over 150 published papers and acts as a consultant for industry. In addition he is an editor for the IEEE Transactions on Wireless Communications and was also the technical program chair of the Advanced Wireless Communication Systems Symposium at the 2002 IEEE International Conference on Communication in New York. He is also the founding Director of the Center for Wireless Information Technology which was begun in August 1997.

2004

Dr. Peter Smith

Associate Professor
Dept. of Electrical and Computer Engineering
University of Canterbury
Christchurch
New Zealand

Bensted Lecture Title

MIMO channel models in space, time and polarization: How complex should they be?

Research Interests

• Statistical design and analysis of communication systems
• Digital mobile radio systems
• Antenna arrays
• Multiple-input-multiple-output (MIMO) wireless systems
• Simulation