Extensive use of Internet and huge demand for multi-media services via portable devices require the development of packet-based radio access systems with high transmission efficiency. Advanced radio transmission technologies have recently been proposed to achieve this challenging task. The use of multiple antennas, known as multi-input multi-output (MIMO), is one of key technologies toward this challenge. This tutorial gives a complete overview of various emerging multi-antenna techniques. It includes beamforming, single-user MIMO, multi-user MIMO and opportunistic MIMO techniques. In particular, the opportunistic MIMO techniques are very new ones that can achieve both the diversity and multiplexing gain simultaneously, providing significant performance gain over the previous MIMO techniques. In addition, this tutorial addresses some hot issues related to the realization, including the flexibility of MIMO configuration, estimation of channel state information, feedback signaling burden for the MIMO information and the effect of channel correlation.

Young-Hwan Lee , received his B.S. degree from Seoul National University (SNU), Seoul , Korea , in 1977, the M.S. degree from Korea Advanced Institute of Science and Technolgy (KAIST), Korea in 1980, and the Ph.D. degree from the University of Massachusetts , Amherst , USA , in 1989, all in electrical engineering. From 1980 to 1985, he was with the Korea Agency for Defense Development as a Senior Research Engineer. From 1988 to 1994, he worked for Motorola, Inc., USA , where he was involved in the development of data transceivers including high-speed modems. Since 1994, he has been with the School of Electrical and Computer Engineering, SNU, where his is currently a Professor. He served as Director of Institute of New Media and Communication SNU from 2001 to 2003 and is now serving as a Vice Chair of the School of Electrical and Computer Engineering, SNU. He is also serving as Chair of the Seoul Industry Forum from 2004 and a Guest Editor of international Journals including the IEEE JSAC and JCN. He was a Vice Chair of Technical Program Committee of IEEE VTC2003 and ICC2005 conferences. He gave a number of technical tutotial presentations on the subjects related to this proposal. His research areas include the development of wireless transceivers, multi-antenna technology and robust signal processing for communications.