6G Fronthaul Network Architecture Based on Quantum Technology: Integration of QKD with Passive WDM

The rapid evolution of mobile communication technology is propelling us from the era of 5G to the cusp of 6G, which promises ultra-high speeds, ultra-low latency, and seamless global connectivity. However, these ambitious goals require not only significant advancements in traditional communication technologies but also the integration of novel approaches to address emerging security and efficiency challenges. Quantum communication, particularly Quantum Key Distribution (QKD), offers a groundbreaking solution due to its inherent security based on the principles of quantum mechanics. This paper proposes an innovative architecture that combines QKD with Passive Wavelength Division Multiplexing (WDM) for 6G fronthaul networks. The architecture, which includes components for signal transmission, processing, and monitoring, uses WDM to transmit both quantum signals and classical signals over a single fiber, optimizing resource utilization, ensuring security, and enhancing reliability. The quantum signals are detected by single-photon detectors to generate secure keys, while the classical signals carry regular communication data. The passive WDM system efficiently uses fiber resources, is cost-effective, and is easy to upgrade, making it highly compatible with classical optical communication. Extensive simulation experiments are conducted to evaluate the impact of key parameters such as transmission distance, attenuation coefficient, photon count per pulse, dark count rate, and detection efficiency on the secure key rate and quantum error rate. The results indicate that careful optimization of these parameters can substantially enhance system performance, making the architecture highly suitable for high-security transmission scenarios in 6G networks. This research provides new insights into the integration of quantum and classical communications in 6G fronthaul networks, demonstrating the potential of quantum-enhanced 6G networks.