Linearly constrained adaptive arrays based on a quadratic Constant Modulus criterion

Abstract

This paper considers the application of the linear constraints in Recursive Least Squares, Affine Projection and Normalized Least Mean Square adaptive filtering algorithms that are used in Adaptive Arrays which receive desired signals with Constant Modulus envelope. The computational procedures of the algorithms are presented. Arithmetic complexity of the algorithms is estimated. Array efficiency for Phase Shift Keying signals is demonstrated via simulation. It is shown, that a fixed phase shift in the array output signal, caused by angular orientation of desired signal source and array weights, is compensated in a simple way by means of a linear constraint.