5G compatible front-haul transmission of OFDM-MIMO signal over multicore fibers

A bidirectional transmission and massive MIMO enabled radio over multicore fiber system with centralized optical carrier delivery is experimentally investigated. Optical carriers for upstream are delivered from the central office (CO) to the remote antenna unit (RAU) via the inner core for the coreless implementation. As one of the 5G waveform candidates, orthogonal frequency division multiplexing using offset quadrature amplitude modulation (OFDM/OQAM) is adopted in both uplink and downlinks. The experimental results show that bidirectional transmission of 4.46 Gb/s 2×2 MIMO-OFDM/16-OQAM could be achieved over 20 km 7-core fiber and 0.4 m wireless link. The proposed scheme proves multicore fiber can realize the transparent transmission of bidirectional radio signals and simplify the infrastructures of future 5G cellular systems.