A novel radio-over-fiber (ROF) system has been proposed and simulated, which is based on orthogonal frequency division multiplexing (OFDM) and asymmetrical filtering of optical carrier suppression (OCS) technique, so it can effectively suppress the fading effect caused by power periodic variation in traditional OCS system. Simulation results show that the 2.5 Gbit/s OFDM-modulated wideband wireless signal can be transmitted over 25 km single mode fiber (SMF) successfully.