Reflection-Tolerant RoF-Based Mobile Fronthaul Network for 5G Wireless Systems

We propose to utilize the filtered Gaussian phase dither technique for the effective suppression of the multipath- interference (MPI) noises caused by multiple bad fiber connectors in the mobile fronthaul network (MFN) based on the radio-over- fiber (RoF) technology. We first evaluate the viable performances of the RoF-based MFN in the 5G wireless communication systems by using this technique and deduce the required bandwidth and phase modulation depth of the filtered Gaussian dither signal for the suppression of the MPI noises by numerical simulations. The results show that, by using the proposed technique, it is possible to suppress the MPI noises by ~10 dB regardless of the number of bad fiber connectors. These simulation results are experimentally verified in the RoF link capable of transporting the 5G wireless signals (i.e., thirty-two 100-MHz orthogonal-frequency-division- multiplexed (OFDM) signals modulated in 64QAM or 256QAM format). We also evaluate the effectiveness of the proposed dither technique in a high-capacity RoF link implemented by using four wavelength-division-multiplexed channels and demonstrate the successful transmission of 128 100-MHz OFDM signals modulated in 256QAM format in the presence of multiple bad connectors.