Scheduling Policies for Quantum Key Distribution Enabled Communication Networks

The upsurge of ubiquitous data-driven applications makes the need for super-secure communication networks more urgent than ever. Conventional encryption algorithm oriented cryptology would be hacked by cryptanalysis, hence is challenging to provide unconditional security. To tackle this unprecedented issue, quantum key distribution (QKD) has been envisioned as a promising physical layer security technology for the upcoming 6G era due to the unique properties of quantum physics, i.e., no-cloning and uncertainty. To accommodate as many security-sensitive applications as possible, in this letter, the secure key rate maximization problem for QKD enabled communication networks is investigated. By transforming the original problem into a maximum weight perfect matching problem of an undirected and non-bipartite graph, the associated quantum devices scheduling policy is optimally determined, along with the feasibility analysis as well as two simpler heuristic scheduling approaches. Numerical results demonstrate the performance of the devised scheduling strategies from comprehensive perspectives, such as achievable secure key rate and outage probability.