Advanced Multi-Antenna Techniques

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 multiantenna 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.