Patent ID: 7440519

Claim:
A method for multiple-symbol differential detection phase evaluation of MPSK communication data comprising the steps: a) observing a received set of N sequential symbols r 1 to r N , each pair of consecutive symbols having a phase differential from among M phases where M>2; b) evaluating the set of symbols r 1 to r N based on selected sequences of N−1 elements that represent possible sequences of phase differentials selected from the set (2πk/M, k=0, 1, . . . , M−1); c) selecting S N−1 candidate phase sequences of the form (P 2i , P 3i , . . . , P Ni ) for i=1 to S for evaluating said symbol set, where 1<S<M, and wherein S candidate phases β k1 to β ks of the M phases for each k that are closest to the actual phase differential are selected from the set (2πk/M, k=0, 1, . . . , M−1), which produce the S largest values using the expression |r 1 +r k+1 e −jβ k | 2 , resulting in N−1 sets of S phases; d) determining the optimum phase differential sequence from among the candidate phase sequences.