From Link Diversity to Cross-Band Feedback Collaboration: A New Perspective on Hybrid Optical-RF Systems

TL;DR

This paper introduces a novel hybrid optical-RF system architecture that leverages optical downlink for real-time feedback to enhance uplink reliability and throughput, shifting from traditional diversity-based approaches.

Contribution

Proposes the O-RF-CBF architecture that uses optical downlink feedback for adaptive RF uplink coding, enabling active cross-band collaboration.

Findings

Achieves significant uplink throughput gains.

Demonstrates the effectiveness of cross-band feedback.

Highlights the importance of inter-band synergy.

Abstract

We suggest a re-examination of the conventional view that hybrid optical-radio frequency (O-RF) systems are primarily diversity-driven networks that switch between RF and optical links for robustness. Instead, we uncover a new architectural opportunity: repurposing the optical downlink to enable real-time feedback channel coding over the RF uplink, where structured decoder feedback is delivered from the access point to guide the transmitter's coding strategy. This insight marks a conceptual paradigm shift from passive link diversity to active cross-band collaboration, where the wideband, interference-free optical wireless communication (OWC) is no longer merely a downlink backup but a functional enabler of uplink reliability. To realize this vision, we propose a novel architecture, O-RF with Cross-Band Feedback (O-RF-CBF), that exploits the optical downlink feedback to facilitate adaptive RF uplink coding. Numerical results reveal that O-RF-CBF achieves significant uplink throughput gains over traditional O-RF systems. Our findings highlight that inter-band synergy, not redundancy, is the key to unlocking the full potential of hybrid wireless networks.