Mixed substrate cognitive RF/FSO relay transmission system and method

The invention discloses a mixed substrate cognitive RF/FSO relay system and method, and the system comprises an FSO receiving end which receives and combines L paths of parallel FSO signals from a secondary base station; a substrate cognitive radio network which comprises a secondary network composed of a secondary user terminal and a secondary base station and a main network composed of a main user terminal and a main base station, wherein the main user terminal and the secondary user terminal share a frequency spectrum at the interference temperature preset by the main network, the secondary user terminal sends RF signals to a secondary base station and a main base station respectively, and the secondary base station receives the RF signals from the secondary user terminal; and the main user terminal sends an RF signal to the main base station, and the main base station receives RF signals from the main user terminal and the secondary user terminal respectively. According to the hybrid substrate cognitive R