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Space-Time Joint Interference Cancellation Using Fuzzy-Inference-Based Adaptive Filtering Techniques in Frequency-Selective Multipath Channels

  • Chia-Chang Hu
  • Hsuan-Yu Lin
  • Yu-Fan Chen
  • Jyh-Horng Wen
Open Access
Research Article
  • 700 Downloads

Abstract

An adaptive minimum mean-square error (MMSE) array receiver based on the fuzzy-logic recursive least-squares (RLS) algorithm is developed for asynchronous DS-CDMA interference suppression in the presence of frequency-selective multipath fading. This receiver employs a fuzzy-logic control mechanism to perform the nonlinear mapping of the squared error and squared error variation, denoted by ( Open image in new window , Open image in new window ), into a forgetting factor Open image in new window . For the real-time applicability, a computationally efficient version of the proposed receiver is derived based on the least-mean-square (LMS) algorithm using the fuzzy-inference-controlled step-size Open image in new window . This receiver is capable of providing both fast convergence/tracking capability as well as small steady-state misadjustment as compared with conventional LMS- and RLS-based MMSE DS-CDMA receivers. Simulations show that the fuzzy-logic LMS and RLS algorithms outperform, respectively, other variable step-size LMS (VSS-LMS) and variable forgetting factor RLS (VFF-RLS) algorithms at least 3 dB and 1.5 dB in bit-error-rate (BER) for multipath fading channels.

Keywords

Fading Channel Interference Cancellation Multipath Channel Interference Suppression Multipath Fading Channel 

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Copyright information

© Hu et al. 2006

Authors and Affiliations

  • Chia-Chang Hu
    • 1
  • Hsuan-Yu Lin
    • 1
  • Yu-Fan Chen
    • 2
  • Jyh-Horng Wen
    • 1
    • 3
  1. 1.Department of Electrical EngineeringNational Chung Cheng UniversityMin-HsiungTaiwan
  2. 2.Department of Communications EngineeringNational Chung Cheng UniversityMin-HsiungTaiwan
  3. 3.Institute of Communication EngineeringNational Chi Nan UniversityPuliTaiwan

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