In order to overcome the influence of dispersion in long-range fiber-optic transmission systems

we study a simplex Radio-Over-Fiber（ROF） system based on optical carrier suppression and propose an improved duplex ROF system transmission scheme

in which the down-link signals are coupled to the optical carrier suppression band using 20 GHz RF signals at the central station and then transmitted to the base stations over a 50 km single-mode fiber

while the unmodulated sideband is reused to transmit the uplink signals.The system spectrum diagram and BER curve generated in simulation show that when transmitted by coupling with uplink signals

the energy penalty of downlink signal is decreased and both the uplink and downlink become more dispersion resistant.