Joint channel equalization and interference rejection using a modified constant modulus algorithm

Abstract

The authors propose an equalizer structure that combines the properties of both a standard decision-directed equalizer based on a minimum mean-squared error criterion and the '2-1' version constant modulus algorithm (CMA) equalizer. Analytical bit error rate results are presented for a BPSK direct-sequence spread-spectrum system that uses a finite-impulse-response adaptive equalizer based on such a scheme. Severe Frequency-selective distortion and inband tone interference are used as impairments. Preliminary results show 1-3 dB of improvement at low chip energy-to-noise ratios when using a combined CMA and recursive least-squares (RLS) cost function over the decision-directed RLS alone.<>