MMSE detection for high data rate UWB MIMO systems

In this paper, a uniform matrix representation for ultra-wideband (UWB) multiple-input multiple-output (MIMO) systems with time-hopping spread spectrum (THSS) and direct-sequence spread spectrum (DSSS) methods is formulated. The inter symbol interference (ISI) is considered for high data rate UWB transmissions in the presence of dense multipath in an indoor environment. The bit error rate (BER) performance is evaluated based on the minimum mean square error (MMSE) detection criterion. In addition, a simplified UWB MIMO channel model is assumed for performance analysis based on the IEEE 802.15.3a channel model recommendation and the MIMO channel covariance matrix representations. Results show that a UWB MIMO system with THSS method is capable of delivering promising performance up to very high symbol rate transmission for short range. On the other hand, a UWB MIMO system with DSSS method is more vulnerable to high symbol rate transmission due to the existence of severe inter chip interference (ICI) in addition to ISI.