On the Energy-Efficient Design of Multiple Antenna Communication Systems

Hun Seok Kim
Advisor: Babak Daneshrad

Tuesday, February 23, 2010 at 12:00pm
Engr IV Maxwell Room 57-124

Abstract:
In this talk, algorithm level and system level energy optimization techniques for MIMO-OFDM systems will be presented.

Design and implementation of a highly energy-efficient MIMO detector requires co-optimization of the algorithm with the underlying hardware architecture. Special attention must be paid to application requirements such as throughput, latency, and resource constraints with the objective of minimizing the energy consumption and algorithm complexity. In this talk, an energy-efficient matrix inversion free 4x4 MMSE MIMO detector will be presented.

As a system level energy optimization technique, a link adaptation strategy for MIMO-OFDM system will be discussed. The objective of link adaptation is to choose the optimal mode that will maximize energy efficiency subject to a given QoS constraint. The link adaptation problem is successfully formulated as a convex optimization problem with 8 baseband parameters under the control of the link adaptation protocol. Application of the results to a generic MIMO-OFDM radio shows that the proposed strategy can provide an order of magnitude improvement in energy-efficiency relative to a static strategy.

In addition, the adaptive power amplifier (PA) clipping will be demonstrated for a MIMO-OFDM system. The goal is to identify the optimum PA clipping level that delivers the desired bit error rate with minimum energy consumption in the PA. The trade-off between the beneficial effects of reduced peak-to-average power ratio and the detrimental effects of increased clipping distortion will be analyzed.

Biography:
Hun Seok Kim was born in Jeju, South Korea. He received his B.S. degree in Electrical Engineering at Seoul National University, Seoul, Korea. He holds a M.S. degree and is currently a Ph.D. candidate in EE at UCLA. The focus of his research is on wireless MIMO-OFDM communication systems, algorithms, architectures and link adaptation optimizations under advisory of Dr. Babak Daneshrad. He was a technical member of Xiline Co. Ltd., Seoul, Korea (from 2001 to 2004) and Silvus Technologies, Los Angeles, U.S. (from 2006 to 2007). He worked at Texas Instruments during 2005 and 2009 summer. He was a recipient of the Korean Ministry of Information and Communication Government Scholarship.