Soft decision direct-sequence DPSK receivers

Several soft-decision receiver structures are proposed for coded direct-sequence differential-phase-shift-keyed (DPSK) spread spectrum systems operating over pulse-jammed channels. The performance of the maximum-likelihood soft-decision receivers and a number of suboptimal soft decision receivers is considered. Soft-decision receivers require channel side information for satisfactory performance in the presence of pulse jamming. Two techniques are investigated for generating channel side information to mitigate the effects of pulse jamming