Optimal Blind Feedforward Carrier Synchronization for General QAM Modulations

This paper introduces 0 family of optimal blind feed-forward estimators for joint estimation of the carrier phase and frequency offset of general quadrature am-plitude modulated (QAM) transmissions. The asymp-totic (large sample) performance of these estimators is established in closed-form expression. A pmctical im-plementation of the proposed optimally matched esti-mator, which is a computationally eficient approxama-tion of the latter and exhibits negligible performance loss, is also derived. It is shown that the proposed family of constellation-dependent optimal estimators outperforms all the existing carrier synchronizers, and serves as an unifying framework for designing blind feedforward carrier recovery schemes for large QAM modulations. Finally, computer simulations are pre-sented to show the merit of the proposed optimal esti-mators.