The invention provides an operating method of an FSO (
Free Space Optical) communication
system based on an IHDAF (Incremental
Hybrid Decode-Amplify-Forward) protocol, and belongs to the technical field of
wireless optical communication. The FSO communication
system includes a source node, a
relay node and a target node and utilizes a half-duplex operating mode. The operating method of an FSO communication
system based on an IHDAF protocol includes three steps: performing M-order
pulse amplitude modulation on the source information; transmitting the modulated information to the
relay node and the target node through a gauss
laser beam, comparing the link instantaneous
signal to
noise ratio gamma sd from the source node to the target node and the link instantaneous
signal to
noise ratio gamma sr from the source node to the
relay node with the
signal to
noise ratio threshold SNRsd and SNRsr set by the corresponding link so as to determine selecting the corresponding transmission scheme, that is, direct transmission,
Decode and Forward, and
Amplify and Forward; and at last, performing
recovery and
demodulation on the reception signal by means of the target node. The operating method of an FSO communication system based on an IHDAF protocol integrates the relay technology with the
free space optical communication technology in the protocol so as to effectively restrain reduction of system performance, caused by
path loss, atmospheric disturbance and aiming error and improve the transmission reliability of system.