In this paper

we propose a non-decision-aided feedforward carrier frequency offset estimator for rotationally symmetric constellation. It is derived from the maximum likelihood (ML) principle. In order to solve the problem of phase wrapping and extend the estimation range

a new phase unwrapping algorithm is proposed. For 2π/M rotation symmetric constellation

the estimation range can be extended to ±1/(2MT). Computer simulation results demonstrate the estimation range

estimation precision and complexity of the estimator.