Performance Evaluation of Two Kinds of Precoding Joint with MMSE Equalization in DS-UWB

Transmitter-based filters are called "precodes". Two kinds of precoding techniques which are called prerake and zero-forcing pre-equalization (pre-ZF) are taken into account in this paper. Prerake filtering is known as a technique to achieve the performance equivalent to the Rake diversity combining without increasing the receiver complexity. In order to mitigate the leftover inter-symbol interference (ISI), the prerake filter can be replaced by a pre-ZF filter. But we find it is not enough when the channel information is imperfect. Moreover, MMSE equalization is jointly used with precoding and the performance is evaluated in the typical UWB channel models over the single-user link with the data rate of 250 Mbps. Numerical results show that pre-ZF is more efficient when perfect channel states information (CSI) is assumed to be available. But prerake filter with MMSE equalization suffers from much less performance degradation when imperfect channel information is taken into consideration.