【作者】 刘春侠；

【导师】 刘继承；

【作者基本信息】 大庆石油学院 ， 电力电子与电力传动， 2006， 硕士

【摘要】 直接序列扩频技术是近年来发展很快的一种通信技术,因此在军事和民用领域中得到了广泛的使用。它的突出优点之一就是具有很强的抗窄带干扰能力,可以抗来自信道中有意的或无意的窄带干扰。但是,当这些干扰超过接收机的干扰容限时,直接序列扩频通信系统将不能正常工作。因此,需要在接收机中采用相应的窄带干扰抑制技术抑制强功率的窄带干扰,使系统能够正常通信。本文研究的是变换域窄带干扰抑制技术能够更有效地分离信号和干扰,因而变换域窄带干扰抑制技术是目前通信技术的研究热点之一。但变换域的干扰抑制方法有多种,本文重点研究频域窄带干扰抑制技术,频域干扰抑制方法目前应用最广泛,它可以处理多窄带干扰的情况,并且能够快速的自适应。本文介绍了扩频通信系统的特点,研究了直接序列扩频通信系统的工作原理及其抗窄带干扰原理;重点讨论了变换域处理算法——自适应滤波算法,分析了时域LMS算法的局限性。本文主要研究了固定步长频域BLMS算法,分析了固定步长频域BLMS算法的优缺点。针对固定步长频域算法的局限性,对算法加以改进,将频域BLMS算法和变步长技术相结合,提出一种变步长频域BLMS算法,并对两种频域算法进行了计算机仿真。在仿真过程中,以对误码率、功率谱密度以及收敛性能的改善程度为主要参数评判了算法的性能。更多还原

【Abstract】 Direct sequence spread spectrum is a rapidly developed communication technology;therefore, it has been widely applied in the military field as well as in the civil. Its capability ofnarrow-band interference suppression is one of its outstanding advantages, it can suppresspowerful intentional or unconscious narrow-band interference from channel, but when outsideinterference might be more powerful than accepted tolerance, system can’t wok on the rails.Therefore it is necessary to introduce corresponding interference suppressing measures forimproving system performance to make system achieve communications task efficiently in thepowerful interference environment.This paper studies transform domain narrow-band interference suppression technology,which separates signal from interference among many narrow-band interference suppressingtechnology in DSSS. Therefore it is has become one of research hotspots of communicationtechnology at present. But transform domain narrow-band interference suppression measureshas many kinds, this paper mostly studies frequency interference suppression measure, which isused most extensively and can deal with many interference and can be quickly adaptiveThis paper expatiate on characters of spreading frequency communication system, studieswork principle and narrow-band interference suppression principle of DSSS, mostly studiestransform domain disposal algorithm—adaptive filter algorithm, analyzes localization of timedomain LMS.This paper mainly studies fixed step frequency domain BLMS algorithm and analyzescharacters of the algorithm. This paper aims at the localization of frequency domain BLMSalgorithm, improves the algorithm, and presents a variable step-size adaptive BLMS algorithmin frequency domain by combining frequency domain BLMS fast algorithm with variablestep-size technique, makes computer simulation. It is to judge performance of algorithm basedon the improvement of bit error rate and power spectrum and convergence in the process ofsimulation.更多还原