Laboratory demonstration of FSO ground-to-train communications with multiple base stations

In this work, a line-of-sight free space optical (FSO) link for the ground-to-train communications is presented. The measured ß-factor performance along the rail track for the proposed prototype system was analysed. We demonstrate a downlink error-free communications (i.e., a bit error rate of 10
^-6
) over four regions of the track using multiple identical base stations transmitting the same information. Also, an error-free 25 Mbps FSO ground-to-train link of 1 m length was demonstrated using a 13 MHz raw bandwidth light emitting diode (LED). Also investigated experimentally is the effect of ambient light induced noise on the ground-to-train communications link during sunrise and sunset in a laboratory environment. Additionally, the practical results obtained are scaled to the outdoor FSO link in terms of the optical power density.