Joint millimeter-wave communication and optical multipath interference localization for RoF mobile fronthaul

Area of Science:

• Optical Communications
• Wireless Networking
• Signal Processing

Background:

• Millimeter-wave (mm-wave) radio-over-fiber (RoF) technology is crucial for 5G and beyond mobile networks, but faces challenges in component cost and optical multipath interference (MPI).
• Existing solutions struggle with high-cost optoelectronics and susceptibility to reflections in large-scale fiber networks.

Purpose of the Study:

• To propose and demonstrate a joint mm-wave communication and MPI localization scheme for high-capacity mm-wave RoF links.
• To address the cost and MPI vulnerability challenges in mm-wave RoF systems.

Main Methods:

• A novel linear frequency modulation single sideband (LFM-SSB) waveform is generated by combining a virtual-carrier-aided SSB signal with a digital LFM carrier.
• The virtual-carrier-aided SSB signal facilitates photonic-aided mm-wave up-conversion, while the LFM carrier enables MPI localization.
• Self-heterodyne detection is used, where the LFM carrier is eliminated in the absence of MPI, minimizing transmission impact.

Main Results:

• Simulations show sub-decimeter (5 cm) MPI localization accuracy, robust against large linewidth lasers.
• Experimental validation successfully transmitted a 2 Gbaud 16QAM mm-wave signal at 30 GHz and localized a single MPI reflection path at 107.46 m.
• The system achieved an MPI localization resolution of 9.78 cm and supported up to 6 Gbaud 16QAM signals, locating two MPI paths.

Conclusions:

• The proposed LFM-SSB scheme offers a cost-effective solution using large-linewidth lasers without sacrificing accuracy or capacity.
• The joint communication and localization scheme effectively mitigates MPI issues in mm-wave RoF systems.
• This technology paves the way for more reliable and high-performance next-generation mobile fronthaul networks.