Self-Pilot Tone Based Adaptive Threshold RZ-OOK Decision for Free-Space Optical Communications

This paper studies a novel self-pilot tone based adaptive threshold return-to-zero on-off keying (RZ-OOK) decision for free-space optical (FSO) communications. RZ-OOK has the characteristics of impulse series in spectrum. Therefore, these impulses can be utilized as pilot tones transmitted signal to convey channel state information (CSI) FSO links. Then, CSI is extracted using local oscillator (LO) with frequencies and low pass filter. Finally, (ATD) realized by assigning optimized weight factors into signal. The proposed was studied simulation under various pulse durations LO. Simulation results demonstrated that tone-extracted factor performs close conventional ATD precise knowledge.