Study On Rake Receiving Technology In UWB Wireless Communication System

Ultra-wideband (UWB) technology has attracted considerable interest in the research of wireless communication, due to its promising ability to provide high data rate at low cost with relatively low power consumption.This paper mainly studies DS-UWB system, and focuses on the Rake receiving technology in it. On the basis of exploring the fundamental principles, key techniques and channel models in the UWB wireless communication system, this paper, using Matlab environment, analyzes the effects of the selecting and combining patterns of the traditional Rake receiver in the UWB system on the receiver performance. This paper also gives a further study on how to apply the channel coding technique to the UWB communication. Judging from the artificial result, we know the fact that we can decrease not only the system errors by using concatenation code combined internal code with external code, but also the complicity by using short code.Through exploring the technique of Multiuser Detection (MUD), this paper mainly probes into the adaptive DS-UWB plan for MUD based on MMSE. MMSE adaptive detector has not only the advantages of the traditional detector when the noise is bigger than that of MAI, but also the advantages of the decorrelation detector when the noise can be neglected. Aiming at MMSE adaptive MUD receiver, this paper puts forward the adaptive receiver plan by adopting the method of NLMS based on length-variable training sequence. The plan is able to improve the transmission capacity effectively with the least training consumption from the premise of little cost, low power consumption, simplicity and practicality and certain error code.Finally, this paper proposes Rake-MMSE mixed adaptive receiver from taking a middle way of system performance and complicity, artificially analyzes Rake's fingers number, taps number of equalizer and the effect of channel estimation error on Rake-MMSE receiver performance, and proves that the proposed Rake-MMSE mixed receiver is a compromise between the higher complicity MUD receiver and n finger Rake receivers using traditional MRC. Among the three receivers in UWB communication, the proposed Rake-MMSE performs the best comprehensively.