Steady-State Performance of Adaptive Differential Constant Modulus Multiuser Detection

The differential constant modulus (DCMA) multiuser detection can obtain higher steady-state decorrelating performance than the conventional linear algorithm under high SNR condition similar as the constant modulus algorithm (CMA). Unlike CMA criterion, DCMA has single global minimum which leads to the convergence independent from the amplitudes of received signal. However, the closed-form analysis for its steadystate performance in additional Gaussian-white-noise (AWGN) channel is scarce due to the complication of analyzing the nonlinear updates in their adaptive implementation. Here, an analysis approach based on ordinary differential equation (ODE) is proposed to derive the closed-form excess mean-square error (EMSE) expression of the multiuser detections. The simulation and the comparison verify the results of the analysis.