Patent ID: 6842496

Claim:
A system for performing multiple-symbol differential detection in a communication receiver for a received set of N sequential r k symbols (r 1 to r N ), each pair of consecutive symbols having a phase differential from among M phases where M>2, comprising: N−1 parallel selection circuits, each for producing a set of S candidate phases from the set (β k =2πk/M, k=0, 1, . . . , M−1), where 1<S<M, each selection circuit comprising: delay elements for allowing evaluation of the sequential symbols; M multipliers for producing parallel products (r k )(e −jβk ); a decision element for choosing S candidate phases which produce the S maximum values within the expression |r 1 +r k+1 e 31 jβk | 2 ; and S multipliers for producing the products (r k+i )(e −jβ′k ), where (i=1 to N−1) and β′ k represents one of S selected phase candidates; a summer for adding the product outputs of the N−1 selection circuits; and a decision element for evaluating the S N−1 phase sequences from the N−1 parallel selection circuits and selecting the phase sequence which produces the maximum product value.