Beamforming and Combining Strategies for MIMO-OFDM over Doubly Selective Channels

Beamforming and combining strategies are extensively used to harness spatial diversity gains in MIMO-OFDM systems. However, traditional approaches are ineffective when time-variations in the underlying wireless channel introduce inter-carrier interference (ICI). We propose novel beamforming and combining strategies for such time- and frequency-selective wireless channels. Results show that our schemes enjoy large gains over traditional approaches. Additionally, we find that our schemes are robust to the use of predicted (as opposed to perfect) channel state information at the transmitter.