【作者】 胡建凯；

【导师】 曾兴雯；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2002， 硕士

【摘要】 本文以第三代移动通信系统主流空中接口方案WCDMA系统为背景，主要研究了WCDMA上行链路RAKE接收机中的symbol级算法——信道估计技术。由于WCDMA系统上行链路采用的是基于相干解调的RAKE接收方案，故要求对信号在多径衰落信道中所经历的衰落作出准确实时的估计，以便在RAKE接收机中实现相位纠偏和相干接收。本文以WCDMA系统上行专用信道所采用的间断导频发送方式为背景，对几类实用的间断导频信道估计算法进行了研究，而且针对衰落信道的特征，对各类算法的性能作出了理论分析。并且，本文还就DFALP(基于判决反馈的自适应前向预测)算法的结构提出了一种改进算法DFALP-RAKE，该算法通过增加预判值的多径平均单元，改善了DFALP算法在低信噪比环境下的接收性能。最后，本文对讨论的几类算法进行了系统链路级仿真，通过仿真结果进一步验证了各种算法在不同信道环境下的接收性能；同时，仿真结果也表明，DFALP-RAKE改进算法的确能够使系统的接收性能在低信噪比环境下得到明显的改善。更多还原

【Abstract】 The subject of this paper is channel estimation technology of the RAKE receiver in WCDMA system, which is the chief solution of the 3rd generation mobile communication. Since WCDMA up-link adopt the RAKE receiver using coherent detection system, the exact and Real-time channel fading estimation of the transmitted signal is needed to realize the phase correction and coherent reception. In this paper we bring out several applied channel estimation algorithm using time multiplexed pilot assisted transmission format. And we also analyze the performance of every algorithm under various fading conditions. In addition, this paper put forward a modified algorithm DFALP-RAKE. By adding a multipath averaging unit, the DFALP-RAKE algorithm improve the performance of the RAKE receiver. At last the paper include system simulation of all algorithms, and the result of simulation under different fading condition verify that the conclusion of analysis is reasonable. Also do the simulation results show the performance improvement of the modified DF ALP-RAKE algorithm in low SIR condition.更多还原