Adaptive reduced-rank interference suppression for DS-UWB systems based on the Widely Linear Multistage Wiener Filter

We propose a Widely Linear Multistage Wiener Filter (WL-MSWF) receiver to suppress the multi-user interference and the inter/intra-symbol interference in a high data rate Direct Sequence Ultra Wideband (DS-UWB) system. To this end, a non-circular modulation, e.g., Binary Phase Shift Keying (BPSK), is applied. We develop reduced-rank versions of the Least Mean Square (LMS) and the Recursive Least Squares (RLS) algorithms based on the theory of the WL-MSWF. The convergence performance of the proposed WL-MSWF algorithms is shown via simulations in a line-of-sight office scenario and then compared to the linear estimation counterparts. In order to reduce the power consumption due to the high-speed and high-resolution Analog-to-Digital Converters (ADCs), we also evaluate the performance of the WL-MSWF algorithms when a one-bit ADC is employed. The proposed WL-MSWF receiver does not only have a lower complexity compared to the full-rank scheme, but also exhibits a superior performance to the corresponding linear receiver employing the existing MSWF.