Improving signal capture of CMA adaptive array using weight norm control

Abstract

The CMA (constant modulus algorithm) adaptive array was developed to capture the desired signal possessing constant envelope properties. The CMA is an algorithm that is suitable for mobile communications because it has the great advantage of requiring no prior knowledge about the transmitted signal. We propose an alternative norm-constrained CMA. It features putting a hard or rigid constraint on the weight norm. We examine, via computer simulation, the directional patterns after convergence and the output power characteristics versus the iteration number of weight update. In addition, we analyse the capture performance of the proposed system using a 2-wave radio model. The results show that the proposed norm-constrained CMA yields lower sidelobes, resulting in higher SINR, and better signal capture performance than the original CMA and conventional norm-constrained CMA.