Research And Realization Of Channel Estimation On Ultra-wideband Communication Systems

UWB(Ultra-wideband) communication has been the subject of extensive research in recent years due to its unique capabilities and potential applications, particularly in short-range multiple access wireless communications. Channel estimation is one of the key technologies in the ultra-wideband communications systems which must be solved. In this paper, aiming at the difference of Direct-Sequence UWB system and Time-Hopping system, after the analysis of architecture, signal and IEEE 802.15.3a channel model and the performance of maximum likelihood channel estimation, and with the performance of maximum likelihood channel estimation, the simulation experiment is carried out in which the training symbols maximum likelihood algorithm is adopted. The results show that the different impact and performance of channel estimation between the PAM and PPM modulation. Through comparing the angle of delay and amplitude curves, as well as BER, the performance of UWB channel estimation is analyzed by using binary modulation system. Most Ratio Combined (MRC) Rake receiver is adopted at the receiving end, the simulation results show that Ultra Wideband radio is of good performance in low SNR by analyzing the Delay and the Loss which generated by channels. And direct sequence ultra wideband scheme are batter than that of binary time-hopping pulse-amplitude-modulation scheme. Because the optimum ML estimator does not use the prior knowledge for the multipath channel, a joint maximum-likehood(ML) and Minimum Mean Square Error(MMSE) was presented for more precise channel estimates based on the assumption of exponential multipath decay. Theoretical analysis and simulation results show that the scheme further improves the estimation performance of channel gains and multipath delays compared with the ML channel estimator.