Transport of Rel-15/16 waveform radio signals over optical 5G fronthaul path

The paper presents basics of the C-RAN network architecture, based on fiber-optic networks, for solutions targeted at 5G mobile systems. Service aspects of work the optical fronthaul (FH) and optical midhaul (MH) are presented. Such networks will constitute main component connecting the virtual baseband unit (vBBU) cloud and the physical active antenna (AAU)/ optical remote radio head (O-RRH) nodes. Calculations were made to indicate the impact of optical fiber path/link delay parameters on the functioning of a interface using D-RoF or A-RoF formats. Simulations of 5GRFoF signal transmission over the fiber-optic FH path up to 20km in length were carried out. During the simulation, the 5G-NR signal according to Rel-15/16, i.e. CP-OFDM with the maximum number of subcarriers supported by 4096-point DFT/FFT was used in the radio channel. Selected simulation results have been summarized in tabular form and in the form of visualization of the 256-QAM constellation. The summary indicates the need to consider the static parameters of the FH/MH fiber-optic link when synchronizing signals delivered to gNB-DU as a remote AAU/O-RRH group.