Pre-distortion schemes for MISO single-user ultra-wideband systems

This paper presents a performance analysis of a baseband multiple-input single-output (MISO) ultra-wideband system (UWB) over the scenarios CM1 and CM3 of the IEEE 802.15.3a channel model, incorporating three different schemes of pre-distortion: time reversal (TR), constrained least squares (CLS) pre-equalizer, and minimum mean square error (MMSE) pre-equalizer. For the second case, a simple cost function for the pre-equalization problem is considered and a simple solution based on the steepest descent (gradient) algorithm is adopted and compared to theoretical results. The channel estimations at the transmitter are assumed to be truncated and noisy. Results show that the CLS algorithm has a good trade-off between intersymbol interference (ISI) reduction and signal-to-noise ratio (SNR) preservation, providing a performance compared to the MMSE method.