Interference Suppression for Railway Radio-over-Fiber Communication Systems

Radio-over-fiber (RoF) is a promising technology for railway communication systems. The base station (BS) transmits to and receives from the mobile station (MS) through geographically distributed remote antenna units (RAU), which are individually connected to the BS via fiber of different length. Unequal fiber length may cause severe inter-symbol interference (ISI) beyond the system capability and cause disconnection. We propose an RAU power switching method, which adjusts the RAU power according to MS´s position on the rail to suppress the ISI. We further consider two MSs crossing each other and extend the RAU power switching method for this case. The effectiveness of the proposed method is verified by simulation results conducted via practical BS/MS and channel emulator.