Hybrid 60 GHz and 2.4 GHz WLAN radio-over-fiber system for efficient broadband signal distribution

This paper presents a hybrid MMW and WLAN ROF system for efficient broadband signal distribution in transportation. The 60 GHz MMW band transceivers are used for 1.25 Gbps data transmission, for example at train stations in transportation. The fast downloaded data could be stored in the train server. Then the data can be distributed to mobile terminals through WLAN ROF networks. The gigabit switching hub used is capable of automatic sensing the connected device's speed (10Mbps or 100Mbps) for every individual port. Fiber is used to guide the modulated optical signals to the remote base stations where the broadband signals are detected and transmitted to passengers. The bit-error-rate (BER) results of the MMW ROF system are presented when the fiber length is varied. An optical filter is employed to examine the fading effect in the fiber transmission. Measured error vector magnitude (EVM) results for downlink and uplink of the WLAN RoF system are presented. Video streaming has been conducted successfully through the hybrid RoF system from the MMW server at the central station to the WLAN mobile terminals.