The 5G era is nearly upon us, and poses several challenges for system designers; one important question is how the (soon to be standardized) mmWave bands of wireless mobile access can coexist harmoniously with optical links in fixed telecom networks. To this end, we present a Radio-over-Fiber (RoF) backhauling concept, interfaced to a 60-GHz indoor femto-cell via a field-installed optical fiber link. We successfully demonstrate generation of a RoF signal up to 1 Gb/s and transmit it optically over 43 km of deployed Single Mode Fiber (SMF), as well as investigate the performance of the 60-GHz access link as a function of distance. The optical link introduces negligible degradation, contrasting the effect of multipath fading in the 60-GHz wireless channel; the latter requires adaptive equalization using offline DSP. The proposed scheme is further validated by demonstration of a 60-GHz Remote Antenna Unit (RAU) concept, handling real traffic from commercial Gigabit Passive Optical Network (GPON) equipment. Proper RAU operation at 1.25 Gb/s is achieved, accommodating true data packets from a Media Converter emitting at 1310 nm through an in-building fiber link. System performance is confirmed through Bit Error Rate (BER) and Error Vector Magnitude (EVM) measurements. EVMs of ~11 and 19% are achieved with BPSK signals, for distances of 1 and 2 m respectively. As standardization of mmWave technologies moves from 5G testbeds to field-trial prototypes, successful demonstration of such 60-GHz wireless access scenarios over a telecom operator’s commercial fiber infrastructure is even more relevant.
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