List-Sequential (LISS) Multiple-Symbol Detection of Differential Phase Shift Keying

The application of multi-symbol detectors for FEC coded DPSK allows to achieve significant turbo gains in a non-coherent iterative detection scheme. However, the complexity is increased compared to standard differential DPSK detection based on two received symbols. For example, in a trellis based detector, the complexity grows exponentially with the number of symbols which are taken into consideration. In this paper, we propose to apply a list-sequential (LISS) algorithm with soft augmentation in the turbo scheme in order to overcome the complexity problem. We unveil problems which appear particularly in non-coherent DPSK detection and show that the LISS detector can achieve the same performance as an optimum but prohibitively complex APP detector at reasonable SNR