| 摘要 |
A non-line of sight (NLOS) communications system and method are provided that implement orthogonal frequency, division multiplexing. A data generator produces a digital data stream, which is converted into M parallel frequency sub-carrier digital data streams (where M is an integer), each sub-carrier is encoded with data and an Inverse Fast Fourier Transform operation is applied, and an output signal is converted to an analog signal, which is imposed onto an optical beam generated by a light source. The beam is transmitted skywards at an elevation angle above the horizon in at least one direction. The beam is scattered due to Mie and Raleigh effects, forming a scattered waveform. At least a part of the scattered waveform is received by a receiver outputting an electrical signal, which enters a DSP unit. The DSP unit digitizes the electrical signal, performs Fourier transformation and recovers data from M sub-carrier signals.
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