Carrier frequency estimation in automatic modulation recognition environment

Carrier frequency estimation is important in both cooperative and non-cooperative communications. This paper addresses the estimation of the carrier frequency of a single-tone digitally modulated signal in the automatic modulation recognition (AMR) environment, where the AMR receiver does not have priori knowledge of the transmitted signal such as modulation type, shaping pulse, symbol constellation and symbol rate. Based on the analysis of phase information in autocorrelation functions of the received signal, two carrier frequency estimation algorithms are proposed in this paper. Performance of the proposed algorithms is compared with that of cyclic estimators via simulations, and the results show that the proposed algorithms perform better in AMR environment.