| Ultra wideband (UWB) radio, unlike classic communications, does not use amodulated sinusoidal carriers to convey information. Instead, the transmit signals are series of very short duration pulses that result in very wideband transmission bandwidths. After investigating research reports provided by many universities and companies, the Federal Communications Commission (FCC) in the United States first approved rules for the commercial utilization of UWB in February 2002. Direct sequence code division multiplexing access ultra-wideband (DS-CDMA UWB) has received wide attention and interest because of its higher data rates, low probability of interception and detection, low complexity and low cost.The paper focuses on the research on the corresponding aspects of channel estimation, direction of arrival (DOA) estimation and time of arrival (TOA) estimation algorithm and so on. According to this, the paper is composed of four parts:1 , The paper introduces the UWB channel model adopted by the IEEE 802.15.3a. The number of paths varies from dozens to hundreds, whose estimation accuracy influences system performance. A channel estimation algorithm based on ML criterion is applied to DS-CDMA UWB system.2, DOA estimation is one of the key technologies of DS-CDMA UWB system. The traditional DOA estimation methods which are based on narrow-band signals are not suited for it, so a frequency domain model of DS-CDMA UWB array signals is derived. Then two DOA estimation methods based on the frequency domain model are presented. One method is founded on the second-order statistic; the other is based on the fourth-order cumulant. Simulation results show that these two methods are effective for the DOA estimation and the computation complexity of the former is much lower than that of the latter. The methods cannot deal...
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