Chip Equalization Using Subband Adaptive Decomposition in Downlink MIMO DS-UWB

An adaptive subband chip-equalizer is investigated for downlink multiple-input multiple-output (MIMO) direct-sequence (DS) ultra-wideband (UWB) systems to cope with the inter-symbol interference (ISI) and the multiple-access interference (MAI) in multipath fading channels. The subband decomposition technique is employed to improve substantially the downlink reception of mobile-terminal receivers without compromising the overall computational complexity. A reduced-complexity chip-equalization scheme is proposed by making use of the architecture of the reduced-rank (RR) multistage matrix Wiener filter (MMWF) in subbands. Simulations are conducted to provide a comparative evaluation of the proposed subband chip-equalizer with other existing full-band and subband chip equalizers.