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毕业设计(论文)外文翻译
(原文)
院(系): 应用科技学院
专业: 电子信息工程
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学号:
指导教师单位: 应用科技学院
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职称: 讲师
2011年 6 月 12 日
Adaptive Multiuser Channel Estimation using Reduced
Abstract This paper presents an adaptive multiuser channel estimator using thereduced-Kalman least-mean-square (RK-LMS) algorithm. The frequency-selective fading channel is modeled as a tapped-delay-line filter with smoothly time-varying Rayleigh distributed tap coefficients. The multiuser channel estimator based on minimum-mean-square-error (MMSE) criterion is used to predict the filter coefficie- nts. We also present its convergence characteristics and tracking performance using the RK-LMS the previously available Kalman filtering algorithm based approach (Chen, Chen IEEE Trans Signal Process 49(7): 1523–1532, 2001) the incorporation of RK-LMS algorithm reduces plexity of multi- user channel estimator used in the code division multiple access wireless systems. puter simulation results are presented to demonstrate the substantial improvement in its tracking performance under the smoothly time-varying environment.
Keywords: Kalman filter · LMS algorithm · MMSE · Estimation · Multipath fading
1 Introduction
Code-Division-Multiple-Access (CDMA) system is a spread spectrum technique, which is being widely applied in cellular mobile and other high data rate munication systems for the efficient usage of bandwidth. During the last two decades, mercial use of munication has increased due to the demand for large capacity in terms of the number of users. However, the major limiting factors for capacity in the CDMA systems are intersymbol-interference (ISI) due to the multipath propagation through linear dispersive media ,multiple access interference (MAI) due to the usage of non-orthogonal codes, and additive white Gaussian noise (AWGN). On the reverse link from mobile to base station, the posite signal also includes ISI due to the past symbols of other active users.
The problem of MAI can be reso