Differentially coherent communication with multiple-symbol observation interval

A novel differential detection technique for multiple phase shift keying (MPSK), which uses multiple-symbol observation interval, is proposed and its performance is analyzed. The proposed technique detects the transmitted symbol with accumulation of the differential signal vector projected on the previously received symbol. As with the multiple-symbol differential detection (MSDD) technique, the performance of the proposed scheme fills the gap between the conventional differential and the ideal coherent detection. The amount of improvement depends on the number of phases M and the number of additional symbol intervals N of observation. Performance analysis and simulation show considerable improvement with only 1 or 2 additional symbol intervals of observation. In addition, the complexity increases linearly with observation interval and is smaller than that of Divsalar and Simon (1990) and of Edbauer (1992).