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Multiuser MIMO for Broadband Wireless
Communication Systems
Multiple-input multiple-output (MIMO)
is a promising technology for future wireless communication
systems. By exploiting the multi-dimensional wireless
channel created by multiple transmit and receive antennas,
MIMO systems significantly increase the channel capacity and
link robustness of wireless communication, and have been
widely adopted in many future wireless communication
standards (e.g., WiMAX, 3GPP LTE, etc).
In a multiuser MIMO (MU-MIMO)
system, a single base station transmits to multiple mobile
stations simultaneously over the same frequency band,
thereby substantially increasing the sum data-rate and
reducing the latency of mobile users compared to other
multi-access (MAC) schemes such as conventional TDMA. The
gains achievable by the introduction of the MU-MIMO
broadcast channel in
wireless systems are yet
to be demonstrated in practice, and are forecast to play a
major role in the increase of spectral efficiency of future
wireless networks. Non-linear dirty-paper-coding process
required to achieve the sum-capacity of the MU-MIMO channel
is very difficult to implement in practical systems. In
addition, interuser interference needs to be properly
cancelled at the transmitter to enable low-complexity and
energy-efficient mobile terminals. |
