Recently, large-scale quantum networks that connect metropolitan area quantum networks between cities have been realized by integrating free-space and fibre quantum key distribution (QKD) links, yet the fibre-based trusted nodes in such networks could be subject to constant surveillance and probes. To remove these fibre-channel risks, we consider a network in which a space-based relay, the Micius satellite, executes a sequence of key delivery missions, allowing any two cities to have a shared key. In this work, we develop a comprehensive framework integrated with precise orbital modelling and a cloud statistics model to enable a preassessment of satellite-based QKD applications. Using this framework, we consider three different scheduling strategies and estimate the keys that can be delivered to cities. The results show that the strategy of pursing the maximum number of final keys significantly embodies space-based QKD advantages, while the strategy of considering different levels of missions achieves the delivery of more keys to higher-priority missions. Most importantly, the targeted strategy of pursuing a distribution of final keys delivered that is coincident with the network traffic distribution guarantees individual needs, further promoting the utilization of the delivered keys in practice. We also provide a comparison of the total number of keys delivered by satellites with different-altitude orbits. It is demonstrated that the plan for constructing a low-Earth orbit (LEO) satellite constellation is more efficient than that for employing an expensive high-orbit satellite in terms of achieving potential applications. Our work not only provides a practical method in the near term but also gives the initial exploration to establish the quantum network.
Recently, large-scale quantum networks that connect metropolitan area quantum networks between cities have been realized by integrating free-space and fibre quantum key distribution (QKD) links, yet the fibre-based trusted nodes in such networks could be subject to constant surveillance and probes. To remove these fibre-channel risks, we consider a network in which a space-based relay, the Micius satellite, executes a sequence of key delivery missions, allowing any two cities to have a shared key. In this work, we develop a comprehensive framework integrated with precise orbital modelling and a cloud statistics model to enable a preassessment of satellite-based QKD applications. Using this framework, we consider three different scheduling strategies and estimate the keys that can be delivered to cities. The results show that the strategy of pursing the maximum number of final keys significantly embodies space-based QKD advantages, while the strategy of considering different levels of missions achieves the delivery of more keys to higher-priority missions. Most importantly, the targeted strategy of pursuing a distribution of final keys delivered that is coincident with the network traffic distribution guarantees individual needs, further promoting the utilization of the delivered keys in practice. We also provide a comparison of the total number of keys delivered by satellites with different-altitude orbits. It is demonstrated that the plan for constructing a low-Earth orbit (LEO) satellite constellation is more efficient than that for employing an expensive high-orbit satellite in terms of achieving potential applications. Our work not only provides a practical method in the near term but also gives the initial exploration to establish the quantum network.
Recent the large-scale quantum network that connects metropolitan area quantum networks between the cities is realized by integrating the free-space and fibre QKD links, yet the fiber-based trusted nodes in such network could be subject to constant surveillance and probes. To remove these fiber-channel risks, we consider a network where a space-based relay, Micius satellite, executes a sequence of keys delivery missions, allowing thus any two cities to have a shared key. In this work, we develop a comprehensive framework integrated with the precise orbital modeling and the cloud statistics model to enable a pre-assessment on the satellite-based QKD applications. Using this framework, we consider three different scheduling strategies and estimate the keys possible to deliver to the cities, respectively. Results show that the strategy of pursing the total final keys maximized significantly embodies space-based QKD advantage, while the strategy of considering different levels of missions achieves more keys delivered to a higher priority mission. Most importantly, the targeted strategy of pursuing the distribution of final keys delivered being coincident with network traffic distribution, guarantees the individual needs, further promoting the utilization of delivered keys in practice. We also provide a comparison between the total number of delivered keys by the satellite with different altitude orbits. It is demonstrated that the plans for constructing a low earth orbit (LEO) satellite constellation, are more effective than that for employing an expensive high-orbit satellite, for a realization of the potential applications. Our works not only provides a practical method in the near term but also gives the aforehand exploration to establish satellite-based quantum communication network.
Abstract With the goal of a space-based quantum network is to have satellites distribute keys between any nodes on the ground, we consider an evolved quantum network from a near-term form, in which a space-based relay, Micius, executes a sequence of Satellite QKD (SatQKD) missions, allowing any two cities to have a shared key. Accordingly, we develop a comprehensive framework integrated with precise orbital modelling and a cloud statistics model to enable a preassessment of SatQKD. Using this framework, we consider three different scheduling strategies and estimate the keys that can be delivered to cities. By the assistance of using different optimizations on scheduling problem formulations, it is possible to allows for the possibility to consider strategies for different missions such as extending connection for distant nodes, prioritized delivery to nodes with higher privileges, and promoting keys utilization. We also provide a comparison of the total number of keys delivered using different-altitude satellites. It is demonstrated that the plan for constructing a low-Earth orbit (LEO) satellite constellation is more efficient than that for employing an expensive high-orbit satellite to an execution of scheduling SatQKD.
With the goal of a space-based quantum network is to have satellites distribute keys between any nodes on the ground, we consider an evolved quantum network from a near-term form, in which a space-based relay, satellite executes a sequence of satellite-based quantum key distribution (SatQKD) missions, allowing any two ground nodes to have a shared secure key. Accordingly, we develop a comprehensive framework for the dynamic simulation of SatQKD and consider scheduling QKD downlink in future space-based quantum communication network. The embedding of precise orbital model including beam diffractions and atmosphere effects makes our framework more realistic. Incorporated with the local meteorological data to channel loss model, the cloud cover contribution to transmission disturbance is quantified to realize a quasi-experimental scenario. We provide a trade-off consideration between the duration available for communications and its corresponding average link loss during one orbit, which could be used to support decisions involving the locations of ground stations and the selection of the orbital parameters for a quantum satellite. Our work also shows that satellite downlink schedule could allow for the possibility to consider strategies for different SatQKD missions such as extending connection for distant ground nodes, prioritized delivery, or promoting keys utilization, which can be used as a guideline to support decisions for future satellite application.
Satellite-based quantum key distribution (QKD), leveraging low photon loss in free-space quantum communication, is widely regarded as one of the most promising directions to achieve global-scale QKD. With a constellation of satellites and a set of ground stations in a satellite-based QKD system, how to schedule satellites to achieve efficient QKD is an important problem. This problem has been studied in the dual-downlink architecture, where each satellite distributes pairs of entanglements to two ground stations simultaneously. However, it has not been studied in the single downlink architecture, where satellites create keys with each individual ground station, and then serve as trusted nodes to create keys between pairs of ground stations. While the single downlink architecture provides weaker security in that the satellites need to be trusted, it has many advantages, including the potential of achieving significantly higher key rates, and generating keys between pairs of ground stations that are far away from each other and cannot be served using the dual-downlink architecture. In this paper, we propose a novel opportunistic approach for satellite scheduling that accounts for fairness among the ground station pairs, while taking advantage of the dynamic satellite channels to maximize the system performance. We evaluate this approach in a wide range of settings and demonstrate that it provides the best tradeoffs in terms of total and minimum key rates across the ground station pairs. Our evaluation also highlights the importance of considering seasonal effects and cloud coverage in evaluating satellite-based QKD systems. In addition, we show different tradeoffs in global and regional QKD systems.
Abstract With the goal of a space-based quantum network is to have satellites distribute keys between any nodes on the ground, we consider an evolved quantum network from a near-term form, in which a space-based relay, satellite executes a sequence of satellite-based quantum key distribution (SatQKD) missions, allowing any two ground nodes to have a shared secure key. Accordingly, we develop a comprehensive framework for the dynamic simulation of SatQKD and consider scheduling QKD downlink in future space-based quantum communication network. The embedding of precise orbital model including beam diffractions and atmosphere effects makes our framework more realistic. Incorporated with the local meteorological data to channel loss model, the cloud cover contribution to transmission disturbance is quantified to realize a quasi-experimental scenario. We provide a trade-off consideration between the duration available for communications and its corresponding average link loss during one orbit, which could be used to support decisions involving the locations of ground stations and the selection of the orbital parameters for a quantum satellite. Our work also shows that satellite downlink schedule could allow for the possibility to consider strategies for different SatQKD missions such as extending connection for distant ground nodes, prioritized delivery, or promoting keys utilization, which can be used as a guideline to support decisions for future satellite application.
Abstract The goal of the space-based quantum network is to form the backbone of the quantum internet for long-distance secure data transfer, networked distributed quantum information processing, and other applications. Consider that the quantum network evolved from a recent form where a satellite performs a sequence of satellite-to-ground quantum key distribution (SatQKD) missions that allow any two ground nodes to have the symmetric encryption keys, we here develop a framework for the SatQKD downlink modelling and scheduling analysis. Incorporated with the orbital calculation and the meteorological data to downlink SatQKD modelling, the dynamic characteristics of the satellite-to-ground optical transmission could be simulated. Our work shows that the satellite downlink scheduling allows for the possibility to consider different strategies for SatQKD missions such as extending connection for distant ground nodes, prioritized delivery and promoting keys utilization, which may guide design and analysis of future missions for future satellite application.