Leveraging Quantum Communication for Secure Industrial IoT Networks: A Novel Architecture for 5G Fronthaul Protection

The Industrial Internet of Things (IIoT) is reshaping modern industries by enabling interconnected, intelligent systems that support real-time monitoring, predictive maintenance, and automated control. However, the growing complexity and scale of IIoT networks expose them to increasingly severe cybersecurity threats that traditional methods struggle to address. To meet these challenges, this paper proposes a novel architecture that integrates Quantum Key Distribution (QKD) with passive Wavelength Division Multiplexing (WDM) technology to secure 5G fronthaul communications between Active Antenna Units (AAUs) and Distributed Units (DUs). In this architecture, AAUs and DUs act as quantum communication entities, exchanging secure keys over optical fibers by allocating quantum and classical signals across different wavelengths. This hybrid approach not only enhances bandwidth efficiency but also significantly improves resistance to eavesdropping and tampering, which are critical vulnerabilities in IIoT environments. To evaluate system performance, simulations were conducted by varying key parameters, including attenuation coefficient, detection efficiency, and dark count rate. Simulation results demonstrate that lowering attenuation coefficients and dark count rates substantially improves the secure key generation rate and reduces the quantum bit error rate (QBER), while increased detection efficiency, although beneficial for signal acquisition, introduces trade-offs by potentially raising the QBER under noisy conditions. Figures presented provide clear illustrations of these trends. By merging quantum communication into IIoT frameworks, this study offers a forward-looking, scalable solution that ensures data confidentiality, integrity, and high-speed reliable communication, paving the way for the secure evolution of industrial networks in the era of Industry 4.0.