Blind parameter estimation of circular transmissions in multiple-access systems

The problem of blind parameter estimation of circular transmissions in multiple-access systems is addressed. A non-data aided algorithm based on the higher-order cyclostationarity features of the received signal is proposed to estimate amplitude, phase, time delay, and frequency shift of each user. Furthermore, a reduced complexity algorithm is proposed to avoid the burden arising from the higher-order cyclic statistic estimation. Simulation results are presented to show the effectiveness of the proposed algorithm to properly operate in severe noise and interference environments.