Design of Mobile Receiver in Ultrawideband Impulse Radio System Using Time-Hopping and PPM Modulation

Ultra wideband (UWB) impulse radio (IR) system has recently being considered for several applications due to its attractive features that include low-power carrierless and ample multipath diversity. Among the various modulation and multiple access schemes, this paper deals with time-hopping (TH) binary pulse position modulation (PPM) operating in the presence of frequency-selective multipath fading downlink channel. We develop two types of low-complexity mobile station (MS) receivers. One is based on the RAKE reception scheme and the other is designed to meet the minimum output energy (MOE) criterion. However, since accurate channel information is crucial for reliable operation, thereby we propose a blind (non-data aided) channel estimator. Simulation results show that the MOE receiver outperforms the RAKE receiver in multiuser environment. Moreover, both the channel estimation algorithm and the MOE reception schemes are shown to be reliable and near-far resistant.