Jointly optimal receivers for the optical pulse-position modulation channel

Jointly optimal receivers that make decisions in the absence of symbol synchronization are derived and analyzed for a pulse-position modulation, optical direct-detection channel. Both receivers that observe the complete sample-path (count record data) and receivers that observe histogram data are studied, and approximations to them are derived. It is seen that jointly optimal receivers are superior to conventional receivers that have separately designed synchronization and decision subsystems. However, their performance advantage is significant only at very low signal levels. Perhaps more significant is that an approximation to the jointly optimal receivers that is much easier to implement than an optimal, separately synchronized receiver achieves nearly the same performance as the latter. Simulation results indicate that the much less complicated receivers that observe histogram data perform as well as receivers that observe the complete sample path at a rather small number of bins per slot