In this paper, we present a quantum-secured optical fronthaul architecture utilizing hollow-core fiber and propose op-timized wavelength allocation for classical and quantum channels, enhancing QKD performance with secure key rate improvement of 14 dB.
The integration of Quantum Key Distribution (QKD) into optical networks has emerged as a promising solution for securing sensitive data transmission in mobile fronthaul applications. However, implementing QKD typically requires dedicated dark fibers, which increases network complexity and deployment costs. This paper explores an approach that leverages Multi-Core Fibers (MCF) to integrate both classical and quantum channels within the same optical fiber, utilizing Space Division Multiplexing (SDM). By dedicating separate cores for quantum and classical channels, the proposed system minimizes the need for additional infrastructure while ensuring secure and efficient communication. Crosstalk between cores, a critical factor in MCF design, is analyzed through simulations, considering parameters such as core pitch and operating spectrum. Results demonstrate the feasibility of achieving minimal inter-core crosstalk for reliable quantum and classical channel coexistence. This study underscores the potential of MCF-based SDM as a cost-effective and scalable solution for future quantum-secured mobile networks.
In this paper, we propose a coupled theoretical model used for noise processing at nodes of hybrid core fiber with single core fiber (SMF)-multicore fiber (MCF), and intra-core noises and inter-core noises are considered in the model. Then, we propose an on-demand quantum secured future fronthaul architecture and a channel allocation algorithm over hybrid core fibers, and the proposed coupled theoretical model is used to calculate the noises in architecture. For fronthaul optical signals, wavelength modes and the number of transceiver modules in the distributed unit (DU) can be dynamically adjusted according to requirements, and the function of load aggregation is adopted. For quantum key distribution (QKD), quantum signals are transmitted in a dedicated core, and wavelength-time multiplexing is adopted to increase the number of quantum secured base station (BSs) while improving wavelength utilization. Finally, simulation results show that proposed channel allocation algorithm can suppress noise about 60% compared to First-Fit. The architecture can save up to 83.3% modules in 7-core feeder fiber, and it is feasible to support 128 BSs. The experimental and simulation results show that the proposed coupled theoretical model matches well with the experimental results, and the quantum bit error rates in experiment are both lower than 2.5%. The results show that the architecture has the advantages of allocating time-space-frequency resources on-demand, saving power consumption, and expanding the number of users. Therefore, it provides a feasible solution for future optical fronthaul networks secured by QKD.
To ensure the security of optical networks in the future, integrating quantum key distribution (QKD) with optical networks is one of the solutions. Moreover, the optical network based on multi-core fiber (MCF) is also one of the ways to improve the transmission capacity. Therefore, we study the integration of QKD into MCF-enabled optical networks. Aiming at the resource allocation problem of MCF-enabled wavelength division multiplexing optical networks, this paper proposes a resource allocation scheme which is suitable for independent-core-transmission of classical signals and quantum signals. For core resource, we propose the alternate core allocation algorithm. For wavelength resource, we propose the iteration-based wavelength allocation algorithm. The overall scheme uses the proposed two algorithms to first allocate the core and then allocate the wavelength. The simulation results show that the proposed scheme has a great improvement in secret key rate (SKR) compared with the benchmark scheme on the regular hexagonal 7-core fiber and 19-core fiber. And the proposed scheme still has good performance under long transmission distance and high classical signal power.
In this paper, we investigate the impact of classical optical communications in quantum key distribution (QKD) over hollow-core fiber (HCF), multi-core fiber (MCF) and single-core fiber (SCF) and propose wavelength allocation schemes to enhance QKD performance. Firstly, we theoretically analyze noise interference in QKD over HCF, MCF and SCF, such as spontaneous Raman scattering (SpRS) and four-wave mixing (FWM). To mitigate these noise types and optimize QKD performance, we propose a joint noise suppression wavelength allocation (JSWA) scheme. FWM noise suppression wavelength allocation and Raman noise suppression wavelength allocation are also proposed for comparison. The JSWA scheme indicates a significant enhancement in extending the simultaneous transmission distance of classical signals and QKD, reaching approximately 100 km in HCF and 165 km in MCF under a classical power per channel of 10 dBm. Therefore, MCF offers a longer secure transmission distance compared with HCF when classical signals and QKD coexist in the C-band. However, when classical signals are in the C-band and QKD operates in the O-band, the performance of QKD in HCF surpasses that in MCF. This research establishes technical foundations for the design and deployment of QKD optical networks.
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.
To satisfy the urgent requirements of security for fifth generation (5G) fronthaul network, quantum key distribution (QKD) technique is taken into consideration as a promising way. In this paper, we first propose an architecture for quantum security beyond fifth generation (B5G) fronthaul optical network, which merges facilities of QKD into the architecture of existing 5G fronthaul network, enabling quantum signals to be transmitted with classical signals within the same fiber. Secondly, theoretical model analysis of interference with quantum signals caused by four wave mixing noise is performed. Moreover, the theory of secure key rate calculation under noise interference is introduced. Lastly, the QKD performance in the proposed architecture is evaluated, which leads to the conclusion that even when the quantity of B5G fronthaul optical channels for classical signals reaches up to 12, the secure transmission distance of QKD is still beyond 20km, which satisfies the demand of B5G fronthaul optical network.