End-to-End Quantum Key Distribution (QKD) from Metro to Access Networks

Derived from quantum cryptography, quantum key distribution (QKD) can deliver secret keys between two users to secure communication under a certain scale. Nowadays, QKD integrated in backbone, metro, and access areas has been respectively studied and tested around the world. Although the experiments in various scenarios can verify the feasibility of QKD, the situation of QKD between two end users from metro to access networks has not been considered up to now. In this paper, we propose a QKD Network (QKDN) architecture for end-to-end QKD from metro to access networks in a costefficient manner. The cost efficiency can be achieved by sharing Quantum Receivers (Qrecs) in the metro network with the Quantum Transmitters (Qtras) in various access networks since the distance between any two end users within a metro network permits to distribute quantum keys. Under such an architecture, an end-to-end QKD scheme is designed to provide secret keys for end users in different access networks, by mapping Qrecs and allocating time slots according to security requests. Through the end-to-end QKD scheme, the occupation of Qrecs and time slots can be appropriately improved. To verify the effectiveness of the scheme, simulation is conducted on two different topologies respectively. Performances are evaluated in terms of three parameters: i) the failure ratio of end-to-end QKD (FQ), ii) the utilization ratio of time slots (TU), and iii) the utilization ratio of Qrecs (QU). Simulation results show that the topology with more nodes will lower the QU by distributing requests to more numbers of Qrecs. Moreover, the topology with bigger node connectivity can lower FQ since a shorter path will be selected to save the unnecessary occupation of link resources for other end-to-end requests.