Design and performance evaluation of a quantum-secured fronthaul architecture for 6G networks

The rapid evolution of mobile communication technology from 5G to 6G brings great opportunities but also poses serious security and privacy challenges. Although 6G networks offer advantages such as ultra-low latency, extremely high data rates, and massive connectivity, their decentralized, AI-driven, and highly virtualized architecture makes them more vulnerable to cyber-attacks. Traditional encryption methods are increasingly incapable of defending against emerging attacks. To address this issue, this paper proposes an innovative quantum-secured passive WDM fronthaul architecture that integrates BB84-based Quantum Key Distribution (QKD) with existing WDM fiber communication technology, balancing high security with feasibility. The architecture adopts an asymmetric design: low-cost quantum transmitters are deployed at distributed AAU sites, while high-performance quantum receivers are centrally installed at DU sites. This significantly reduces hardware costs and simplifies large-scale deployment. In addition, a centralized Key Management Center (KMC) is introduced to enable dynamic key distribution and real-time updates, further enhancing the system’s security and operational efficiency. Simulation results show that under a fiber attenuation of 0.20 dB/km and a detection efficiency of 10%, the system can maintain a relatively high secure key rate and an acceptable quantum bit error rate (QBER) over a transmission distance of 170 km. Furthermore, by optimizing key parameters such as detection efficiency, fiber attenuation coefficient, and the average photon number per pulse, the system’s key generation rate and secure transmission distance can be further improved.