Research On The Performance Analysis Of UWB Rake Receiver And Multi-user Detection Technology

Impulse Radio Ultra-wideband (IR-UWB) technology has recently attracted considerable interests in the research and standardization communities, due to its high data rate, large capacity and immunity to multipath fading. IR-UWB can implement high data rate transmission at low power consumption, low complexity and low cost, which makes it a promising technology for wireless personal area networks (WPAN), close-range high-capacity communications and precise locating.However,Interferences are brought to the detection of signal in receiver in practice, due to several drawbacks of the impulse transmission,such as rapid path fading, density multipath,long delay spread,and multiuser interference,which affect the performance of UWB system severely.In this paper , according to the malti-path interference and multi-user interference , we studied the performance of UWB Rake receiver and the performance of UWB multiuser detection technology in IEEE 802.15.3a channel,tried the best to obtain simple and effective receiver algorithms with suppressing the multipach interference and multiuser interference.The main content is concluded as follows:①UWB IEEE 802.15.3a standard channel was studied. We analyzed the distribution features of multi-path components , such as the time of arrival, amplitude, and energy. And we simulated the impulse response and the power delay profile(PDP) of LOS channel and NLOS channel, pointed out the range of average pulse repetiton period, which could control the intersymbol interference.②The performance of Rake receiver was studied both in presence of ISI and in absence of ISI.At the aspects of absence of ISI ,we simulated the performance of Rake receiver from different aspects,such as different fingers,different combining schemes of multipath,different selecting schemes of multipath, provided the reference for selecting Rake receiver at low data rate.At the aspects of existing ISI, we simulated and analyzed the performance of Rake receiver both in LOS channel and in NLOS channel, and we proposed a kind of receiver model based on Pre-rake combination, analyzed its performance both in theory and in computer simulation.The result showed,the Pre-rake receiver could suppress the inter-symbol interference in UWB system.③We studied the performance of Rake receiver in multiuser environment. We derived the formula of error bit rate,and simulated its performance both in LOS channel and in NLOS channel, and pointed out that the factor of affecting the receiver's performance changed from AWGN interference to multiuser interference when signal-to-noise ration was higher. so we proposed a kind of receiver model based on assistant vector and modified constraints. Theoretical analysis and computer simulation show that it has good anti-symbol interference and the performance of low complexity.④Multi-user detection technology was Studied in ultra-wideband communication. We analyzed the principle, structure and characteristics of the commonly multi-user detector, and then for the features of density multipath,long delay spread,and existing multiuser interference in ultra-wideband wireless communications, we proposed blind multi-user detection RAKE receiver program based on blind adaptive algorithms, and theoretical analysis and computer simulation results showed that the blind multi-user detection RAKE receiver based on Kalman adaptive algorithm had better capabilities of suppressing multi-path interference and multi-access interference.