Patent ID: 7308049
Filing Date: 2007-12-11
Classification: H04L

Abstract:
1. An N-symbol noncoherent demodulator for a differential phase shift keyed (DPSK) type telecommunications signals, comprising: a) means for storing indications of quadrature components X(q) and Y(q) of N consecutive received symbols of the telecommunications signals, where q is an symbol index, and N is an integer equal to at least three; b) processing means for processing said indications according to where i is an iteration index with i=1,2, . . . , N−1, k i is an index of a phase differences between symbols with k i =1,2, . . . , M, with M being the number of permissable phase transitions, and where VX i+1 (k 1 , k 2 , . . . , k i ) and VY i+1 (k 1 , k 2 , . . . , k i ) are quadrature components at the i-th iteration, such that VX i =X(q−N+1), VY 1 =Y(q−N+1) are quadrature components of the first received symbol in the sequence of said N consecutive symbols, and UX i+1 (k 1 , k 2 , . . . , k i ) and UY i+1 (k 1 , k 2 , . . . , k i ) are transforms of the received symbol at the i-th step according to c) decision means for determining a current symbol based on a phase difference Δ(k