Radio over Fiber Based Fronthaul for Next-Generation 5G Networks

In this paper, we present the benefits, limitations, architectures, and milestones of the radio-over-fiber (RoF) network for application in the fronthaul of next-generation 5G mobile networks. RoF is conceived as the fronthaul of the fiber-wireless system based on a centralized radio access network (CRAN), where a fully centralized approach shifts the signal processing from the remote radio heads (RRHs) to a baseband unit (BBU) in a central office. We present our recent advances in RoF-based fronthaul for next-generation 5G mobile networks. Furthermore, we experimentally demonstrate the spectral efficient M-ary quadrature-amplitude modulation ( M-QAM) technique in the wavelength division multiplexed (WDM) hybrid fiber-wireless RoF network using a directly modulated laser (DML) with a symbol rate of 250 MBd (megabaud) on two optical wavelengths. The error vector magnitudes of the overall link for 4/16/64-QAM are below the 3GPP standard for 5G.