RF-chirp phase dither for MPI mitigation in RoF-based 5G mobile fronthaul networks

Area of Science:

• Optical Communications
• Signal Processing
• Telecommunications Engineering

Background:

• Multipath interference (MPI) noise is a key performance limitation in mobile fronthaul networks (MFN) utilizing radio-over-fiber (RoF) technology.
• Gaussian phase dither has been proposed for MPI noise suppression but causes significant optical spectral broadening, increasing chromatic dispersion vulnerability.

Purpose of the Study:

• To propose and evaluate an alternative method for suppressing MPI noise in RoF-based MFNs.
• To overcome the spectral broadening issue associated with Gaussian phase dither.

Main Methods:

• Implementation of RF-chirp dither for MPI noise suppression.
• Comparative analysis of RF-chirp dither against Gaussian dither in a RoF-based MFN.
• Evaluation of optical spectrum width and transmission distance.

Main Results:

• RF-chirp dither effectively suppresses MPI noise.
• The proposed RF-chirp dither achieves a significantly narrower optical spectrum compared to Gaussian dither.
• This narrow spectrum enables a threefold increase in the transmission distance for RoF-based MFNs in the 1.5-µm region.

Conclusions:

• RF-chirp dither is a superior method for MPI noise suppression in RoF-based MFNs.
• The technique enhances system performance by mitigating chromatic dispersion effects through spectral narrowing.
• This advancement significantly extends the reach of optical fronthaul networks.