AoI Minimization with Quantum Key OTP for Secure IoT Data Collection

We propose a mechanism based on a hybrid dynamic observation value, which combines current and expected future age-of-information (AoI) to prevent key exhaustion and alleviate radio congestion during QKD fading. This Mechanism is designed for a network architecture that integrates a free-spaceoptical quantum key distribution (FSO-QKD) downlink with multiple radio-frequency uplinks to support Internet-of-Things devices. Due to the coupling of key and data freshness in one-time-pad encryption, the bursty key generation of QKD merges key and data queues in a way not addressed by conventional AoI or QKD models. We formulate a long-term average AoI minimization problem over the combined queues and develop a co-scheduler that selects devices for FSO illumination and allocates RF uplinks to balance the consumption of key and data resources. Simulations in various key generation rates, device densities, radio capacities, and turbulence levels demonstrate that the proposed scheme outperforms existing baselines. Index Terms-Quantum Key Distribution, Internet of things, Age of information, One time pad.