Symbol error rate of soft-decision multiple pulse position modulation over turbulent channels.

Soft-decision multiple-pulse-position modulation (MPPM) is one of the favored free-space optical communication modulations. This paper derives theoretical expressions for the symbol error rate of both fast and slow fading conditions applied for soft-decision MPPM without channel state information at the receiver as a particular case of nonmemoryless channel conditions. The theoretical expressions for lognormal and gamma-gamma modeled turbulence were successfully verified by simulation.