Low Complexity Adaptive Blind Equalization Using the Frequency Domain Block Constant Modulus Algorithm

Yoon Gi YANG  Sang Uk LEE  

IEICE TRANSACTIONS on Communications   Vol.E82-B   No.10   pp.1694-1698
Publication Date: 1999/10/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Radio Communication
adaptive equalization,  blind equalization,  frequency domain adaptive filter,  

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In this paper, fast algorithms for the CMA (constant modulus algorithm), which is one of the widely used algorithms for blind equalizationi are presented. We propose the FBCMA (frequency domain block CMA) which takes advantage of fast linear convolution in the DFT domain by using the overlap save method. For the FBCMA, a nonlinear error function in the frequency domain is derived using Parseval's relation. Also, an adaptive algorithm in the DFT domain is introduced to adjust the frequency domain filter coefficients. For a block size and filter length of N, the multiplications required for the conventional CMA and proposed FBCMA are on the order of O(N2) and O(N log N), respectively.