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  • Research Article
  • Open Access

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

  • 1,
  • 1,
  • 2 and
  • 1, 3
EURASIP Journal on Advances in Signal Processing20062006:062052

  • Received: 7 March 2005
  • Accepted: 19 July 2005
  • Published:


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 ( , ), into a forgetting factor . 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 . 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.


  • Fading Channel
  • Interference Cancellation
  • Multipath Channel
  • Interference Suppression
  • Multipath Fading Channel

Authors’ Affiliations

Department of Electrical Engineering, National Chung Cheng University, Min-Hsiung, Chia-Yi, 621, Taiwan
Department of Communications Engineering, National Chung Cheng University, Min-Hsiung, Chia-Yi, 621, Taiwan
Institute of Communication Engineering, National Chi Nan University, Puli, Nantou, 545, Taiwan


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© Hu et al. 2006