Patent ID: 8041224

Claim:
An optical communications system, comprising: a laser light source, the laser light source outputting an initial optical beam; a data generator, producing a digital data stream converted into M parallel frequency sub-carrier digital data streams, where M is an integer, each sub-carrier is encoded with data, then an Inverse Fast Fourier Transform operation is applied to all sub-carrier data streams, an output signal is converted to an analog signal in a D/A converter, the analog signal is imposed onto the initial optical beam; a beam forming unit transmits the beam with imposed data skywards at an elevation angle above the horizon in at least one direction; the beam with imposed data being scattered due to Mie and Raleigh effects inside a free-space volume along the beam transmission path, forming a scattered waveform; at least a part of the scattered waveform is received by a receiver, the receiver includes a photodetector receiving optical beam and outputting an electrical signal; the electrical signal enters a digital signal processing unit, the DSP unit digitizing the electrical signal, performing Fourier transformation and recovering data from M sub-carrier signals.