Research On Channel Estimation Technology In UWB Wireless Communication

Ultra-wide band technology (UWB) was developed for military radar in 1960, which uses the spectrum from several Hz to several GHz to transmit electric signals. Through the medium of transient impulse signal and analyzing the received pulse position, information of the object can be detected. Owing to the low energy and multipath propagation environment, the received signal level is rather low and Rake receiver must be used to collect the pulse energy. However, the performance of Rake receiver completely depends on the channel estimation technology. Channel estimation is able to provide more ideal local template signal to the correlation receiver, therefore it is one of the critical technology of UWB.In this paper channel estimation technology and Rake reception are studied for UWB wireless communication. Firstly the characteristic of IEEE 802.15.3a channel model is studied, several key parameters are analyzed, which is the preliminary study for channel estimation.Secondly, two kinds of time domain channel estimation algorithms, data aided maximum likelihood channel estimation and none data aided channel estimation algorithm, for PPM UWB system are studied. The algorithms have their own predominance. In the former case pilot symbols are inserted in each frame, which brings better performance but lower spectrum efficiency. While the latter has lower performance but higher spectrum efficiency.Thirdly, the application of MUSIC algorithm in UWB channel estimation are derived and diagrams are obtained for using MUSIC in UWB channel estimation. Simulations are carried out to evaluate the impact of parameters of MUSIC algorithm on error detection probability.Finally, the performance of RAKE receiver is studied, which includes the impact of distance between transmitter and receiver and number of S-Rake or P-Rake branches. Moreover, the performance of mulituser DS-UWB in multipath environment are also studied.