Evaluation of the Constant Modulus Algorithm Application

Abstract

The convergence behavior of the Least Squares Constant Modulus Algorithm in an adaptive beam forming application is
examined. It is assumed that the desired signal and the interfer¬ence are uncorrelated. The improvement in output SIR with
each iteration of the algorithm is predicted for several different signal environments. Deterministic results are presented for an
environment containing two complex sinusoids. Probabilistic results are presented for a constant modulus desired signal with a
constant modulus interferer and with a Gaussian interferer. The asymptotic improvement in output SIR as the output SIR becomes
high is also derived. The results of Monte Carlo simulations using sinusoidal, FM, and QPSK signals are included to support the
derivations.