On MIMO signal processing for adaptive W-CDMA and OFDM wireless transceivers

In this paper, we consider wideband extensions of narrowband signal processing techniques for MIMO wireless transceivers. The extensions are applied and analyzed on commonly used wideband systems such as W-CDMA and OFDM. We focus on signal processing techniques for channel estimation and correction, including pilot-aided and decision-directed LMS-based adaptive estimation. Simulation study compares cases with one and two transmit/receive antennas and shows that BER of W-CDMA system consistently improves by exploiting multi-path diversity through additional antenna at the receiver, while additional transmit antenna is beneficial under specific channel conditions. BER performance in OFDM is more sensitive to the value of the channel´s smallest eigen-value than to the eigen-spread. In most practical cases, therefore, the sub-channels with small eigen-values are not usable due to poor BER.