An Analog Approach to Suppressing In-Band Narrow-Band Interference in UWB Receivers

Abstract

Due to the huge bandwidth of ultra-wide-band (UWB) systems, in-band narrow-band interference (NBI) may hinder receiver performance. Sources of potential NBI that lie within the IEEE 802.15.3a UWB bandwidth are presented. To combat interference in multi-band orthogonal frequency-division multiplexing (MB-OFDM) UWB systems, an analog notch filter is designed to be included in the UWB receive chain. The filter's architecture is based on feedforward subtraction of the interference, and includes a least-mean-square (LMS) tuning scheme to match amplitudes of the two paths. An 8-bit discrete control is used to adjust the filter's center frequency across the UWB baseband. It was fabricated in TSMC's 0.18-mum process, and experimental results are provided