Two-level modulation scheme to reduce latency for optical mobile fronthaul networks.

Area of Science:

• Optical Communications
• Telecommunications Engineering
• Signal Processing

Background:

• Optical mobile fronthaul networks are critical for 5G and beyond, demanding high bandwidth and low latency.
• Existing systems often face processing bottlenecks and latency issues at remote radio heads (RRHs).
• Integration with existing optical distribution networks (ODNs) is crucial for cost-effective deployment.

Purpose of the Study:

• To propose and demonstrate a novel optical system for reducing processing latency in mobile fronthaul.
• To simplify signal processing requirements at the RRH.
• To validate the system's compatibility with deployed passive optical networks (PONs).

Main Methods:

• Implementation of a two-level optical orthogonal-frequency-division-multiplexing (OFDM) - amplitude-shift-keying (ASK) modulation scheme.
• Directly launching high-rate OFDM signals into a high-speed photodiode (HSPD) at the RRH without complex processing.
• Utilizing a low-bandwidth photodiode (PD) for the low-rate ASK control signal recovery.

Main Results:

• Achieved significant reduction in processing latency at the RRH.
• Demonstrated a simplified system architecture requiring only a low-bandwidth PD for control signals.
• Successfully transported the system over existing ODNs of passive optical networks (PONs) with a 256 split-ratio.

Conclusions:

• The proposed optical OFDM-ASK system offers a simple and low-latency solution for mobile fronthaul.
• The system's compatibility with existing PON infrastructure facilitates cost-effective upgrades.
• This approach is a promising candidate for future high-performance optical mobile fronthaul networks.