DS-UWB Forward Link Adaptive Chip-Equalizer Using Subband Decomposition Technique

A linear chip-level equalizer based on the subband adaptive decomposition is investigated for downlink direct-sequence (DS) ultra-wideband (UWB) systems to cope with both the inter-symbol interference (ISI) and the multiple-access interference (MAI) in multipath fading channels. The sub-band decomposition technique is employed to improve substantially the downlink DS-UWB reception of mobile-terminal receivers without compromising the computational complexity. Additionally, this downlink DS-UWB chip-equalizer is also presented based on the normalized least-mean-square (NLMS) and the recursive least squares (RLS) subband adaptive algorithms to improve the downlink reception of terminal receivers. Simulations are conducted to provide a comparative evaluation of the proposed subband chip-equalizer with other existing fullband chip equalizers.