The Research Of Channel Estimation In UWB Communication System

UWB is one of the most popular wireless communication technologies for many advantages such as high transmission rate, low power consumption, good security, and robustness to multipath and low cost. Transmiting and receive signal by streams of very low power density and ultra-short duration pulses, UWB systems are very suitable for indoor or short-range high-rate wireless communications. For indoor communications, UWB channels exhibit frequency selective fading, with the energy of signals in many paths. If diversity technology is applied, accurate channel estimation and enough fingers are essential for collecting the energy. Because of the complication of UWB channels, it is difficult to design a speed, accurate and simple estimating algorithm. So channel estimation becomes the key point in UWB system.In this paper, the development and the history of UWB are firstly introduced, and then the modulation, signal model and the channel model are emphasized. After analyzing the conventional maximum likelihood estimation strategy, this paper investigates the maximum likelihood estimation strategy which exploits the properties of the UWB channels, and presentes two specific clusters-determine approaches and tests them in simulation: Asumming that the time span of clusters are the same, the length of the tapped delay line model is used as the length of cluster, that is the minimized clustered channel estimation; and take use of the IEEE802.15.3a channel model to calculate the time span of a cluster, that is the IEEE-referenced clustered channel estimation. The result shows that compared with the conventional ML channel estimation strategy these two methods are more effective in BER degradation.