Performance analysis of adaptive receivers for DS/CDMA communication systems |
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Authors: | Fang-Biau Ueng Jun-Da Chen Jia-Yu Yang |
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Affiliation: | Department of Electrical Engineering, National Chung-Hsing University, 250, Kuo-Kuang Road, Taichung, Taiwan |
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Abstract: | Both intersymbol interference (ISI) and multiple-access interference (MAI) are the important issues in code division multiple access (CDMA) multiuser communication systems. The step size of the traditional least-mean-square (LMS) adaptive receivers must be substantially adjusted to overcome the effect due to different channel responses or different numbers of active users. The normalized-LMS (NLMS) algorithm can automatically manipulate the adjustment to avoid the problem just discussed. This paper proposes the symbol-based interference rejection filter with NLMS algorithm and derives both finite impulse response (FIR)- and infinite impulse response (IIR)-type algorithms. We also derive the optimal step sizes and minimum mean-square errors (MSEs) for both the FIR and IIR symbol-based receivers. The complexity of our proposed FIR receiver is lower than that of the conventional chip-based receivers. In addition, it is shown that the bit error rate performance of our proposed symbol-based receivers is superior to conventional one in the simulations. Simulations also show the correctness of our theoretical analysis of minimum MSE. Copyright © 2008 John Wiley & Sons, Ltd. |
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Keywords: | CDMA intersymbol interference multiple-access interference |
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