Research On Key Technologies Of Receiver For Ultra-wideband Communication System

In recent years, there has been an increasing interest in the research area of intermediate and short range wireless communications. As a rising, the ultrawide bandwidth radio (UWB radio) has been the chief scheme that people achieve future high rate intermediate due to its essence and possessing many advantages. Because channel transmission environment of UWB radio is quite complex, there are not only AWGN, but also impulsive noise, NBI, multi-path fading, dispersive, interference produced by other digital communication systems, which have much effect on the performance of UWB radio receiver system, therefore, this dissertation centers on studying the performance of UWB radio receiver in complex channel transmission environment as follows:Firstly, based on the analysis result of the anti-interference performance of TH-PPM signal, the corrected expression of system performance are induced from types of UWB signals under different NBI. Sum up the structure and module of traditional MMSE-RAKE receiver, and the limit and disadvantage in NBIC. Base on the classical linear filter theory and filter alogrithsm, a kind of pre-filter based on bi-I/O consversion filter adaptes to suitable structure of MMSE-RAKE as the new configuration of reveivers, are purposed. The dissertation set up the model for simulation; discuss the choice of key character and some assumption used in the simulation. And quantitatively calculation and simulation to the performance of receiver under the condition that different NBI and power of signal occour are also given. The results show that the method which uses the pre-filter and suitable MMSE-RAKE receiver structure can take enough advantages to the performance of NBIC. Get benefits than the classical UWB receiver, and can be simply realized.Secondly, after discussing the module and constructor of the receiver under AWGN, frequency-sensitive channel and the effect of ISI, the structure and math module for UWB optimal receiver is lucubrated analysis. As the comparator of performance with transmission method, which use one-order statistical vector of received signal to estimate the channel characters, the algorithms model, performance, and disadvantages also discussed, covariance matching method, based on the vector of received signal and high-order statistical accumulation, are proposes in this dissertation for blind channel estimation. By means of this method, the multi-user receiver can take advantage of performance using the channel character achieved from estimation. From the changes of MSE, it gives the comparator and simulation of these two functions, and quantity analysis the detection performance of receiver using the CM method. And the data length, SNR, user number, as important characters, is also included. The result shows that the CM method is better than the TC method with high SNR, and can get obvious advantages compared with the blind channel estimating algorithms based on ML rule, in the multi-access environment, especially when the number bit of samples is a little more.Thirdly, the BER performance of UWB radio system under impulsive noise environment is proposed. The statistical characteristics of in-phase and quadrate components of Middleton An impulsive noise model are studied and analyzed in this dissertation, and as the model of impulse noise, it is proved using two functions that these components are dependent especially for impulsive noise with small indices. And, by employing this dependence between in-phase and quartered components of impulsive noise, a new UWB radio receiver designed for impulsive noise channel is proposed and the exact expression for the average BER of this receiver as a function of SNR and threshold value is discussed. Then, the optimum threshold value is discussed and the simulation result shows that it depends on the indices of impulsive noise greatly. Also, the performance of UWB radio system using the proposed receiver and that of UWB radio system using the classical receiver under impulsive noise environment are theoretically analyzed and are compared with simulation. The results show that an impulsive index and a threshold value influence the performance of UWB system, and the performance achieved by the proposed UWB radio receiver is much better than that realized by the traditional UWB receiver...