Patent ID: 7428272

Claim:
A method for joint phase offset and frequency offset estimator for a multiple phase shift keying transmission, the method comprising the steps of: (i) dividing an overall observing interval LT into N observing intervals each having a predetermined length MT where N and M are an integer; (ii) independently performing phase estimations for the divided N observing intervals to obtain a plurality of phase estimates; (iii) unfolding the plurality of phase estimates obtained in step (ii) to have continuous values between adjacent phase estimates, wherein the step (iii) includes the substeps of: initializing θ M (−1) to zero; initializing Δθ M (−1) to zero; calculating a difference between the i-th estimate phase and the (i −1)-th estimate phase by the following equation: Δθ M (i)≡θ M (i)−θ M (i-1); compensating for the phase difference according to |Δθ M (i)|by the following equation: Δ ⁢ ⁢ θ ^ M ⁡ ( i ) = { Δ ⁢ ⁢ θ M ⁡ ( i ) , for ⁢ ⁢  Δ ⁢ ⁢ θ M ⁡ ( i )  ⁢ 〈 π Δ ⁢ ⁢ θ M ⁡ ( i ) - 2 ⁢ π ⁢ ⁢ sgn ⁡ ( Δ ⁢ ⁢ θ M ⁡ ( i ) ) , otherwise ; and adding an unfolded phase in an (i −1)-th observing interval to the i-th compensated phase difference to obtain an unfolded phase {circumflex over (θ)} M (i) in an i-th observing interval which is indicated as the following equation: {circumflex over (θ)} M (i)={circumflex over (θ)} M (i−1)+Δ{circumflex over (θ)} M (i); and (iv) simultaneously estimating a phase offset and a frequency offset by averaging the unfolded phase estimates and by averaging the phase differences between adjacent unfolded phase estimates, respectively.