Data-aided synchronization of Mges;2-ary coherent CPMreceivers

摘要

Simple joint and nonjoint data-aided maximum-likelihood (ML)estimators are derived for the carrier phase and symbol timing atcoherent continuous phase modulation (CPM) receivers, which implement 4-or 6-time-limited sinusoidal basis functions. It is shown that, due tothe choice of proper basis functions for the signal space, theestimation of symbol timing becomes a special form of phase estimationand leads to a simple synchronizer and that the synchronizers based onthis estimation structure work robustly in steady state, even at lowsignal-to-noise ratios (SNRs). Several approaches to solving the hang-upproblem of symbol-timing tracking loops are discussed, and simulationresults are presented to show both the steady-state and acquisitionperformances of the proposed synchronizers