Sub-channel grouping and statistical water-filling for MIMO-OFDM systems

This paper studies the power control schemes for MIMO-OFDM systems assuming that perfect channel state information is available to both transmitter and receiver sides. Suppose M is the minimum of the transmit/receive antenna numbers, N is the number of subcarriers, we propose a sub-channel grouping technique which groups the MN space-frequency sub-channels into M grouped channels. Three power control schemes are then proposed to allocate the transmission powers over the grouped channels. The proposed schemes perform water-filling over M dimensions rather than MN dimensions, thus they have reduced computation and implementation complexity. Computer simulations are given to evaluate and to compare the capacities achieved by different schemes.