A demodulation method and apparatus is disclosed that is for use on a modulated communication signal. The method includes receiving the modulated signal including a first set of complex symbols and at least one further set of complex symbols; applying a Forward Error Correction (FEC) decoding technique; applying a first phase estimation technique to the first set of symbols; applying a second phase estimation technique to the further set of symbols to determine phase information for the modulation signal using a first phase estimation means; and repeating in part using at least one further phase estimation means to identify the presence of phase rotation. Beneficially the method enables the use of large block sizes in the FEC technique.