Exploiting Potentialities of Dynamic Satellites for Future Space-based Quantum Network: Downlink Scheduling and Orbital Deployment

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.

Coordinated Location-Based Downlink Scheduling in a Cellular CDMA Network with Partitioned Cells

A downlink scheduling scheme called coordinated location dependent downlink scheduling scheme (CLDSS), that combines the intra-cell power allocation and inter-cell transmission coordination is proposed to be used in TD-CDMA networks. In the proposed scheme, each cell in the cellular network is partitioned into co-centric areas based on the load distribution in the cell. The transmissions from base stations are controlled based on the intra-cell load as well as coordinated to minimize inter-cell interference. The average throughput employing the CLDSS is analyzed for a 2-(square) cell system in shallow fading environment with 2 (square) partitioned areas for each cell. Simulation study is also done to validate the numerical results obtained from the analytical study. It is shown that CLDSS scheme can provide soft throughput, i.e. the average throughput remains relatively invariant with the number of users and also provide good performance even in the non-uniform user distribution within a cell. The CLDSS scheme can also improve the fairness in terms of achievable throughput to users anywhere in the cell.

Coordinated Location-Based Downlink Scheduling in a Cellular CDMA Network with Partitioned Cells

A downlink scheduling scheme called coordinated location dependent downlink scheduling scheme (CLDSS), that combines the intra-cell power allocation and inter-cell transmission coordination is proposed to be used in TD-CDMA networks. In the proposed scheme, each cell in the cellular network is partitioned into co-centric areas based on the load distribution in the cell. The transmissions from base stations are controlled based on the intra-cell load as well as coordinated to minimize inter-cell interference. The average throughput employing the CLDSS is analyzed for a 2-(square) cell system in shallow fading environment with 2 (square) partitioned areas for each cell. Simulation study is also done to validate the numerical results obtained from the analytical study. It is shown that CLDSS scheme can provide soft throughput, i.e. the average throughput remains relatively invariant with the number of users and also provide good performance even in the non-uniform user distribution within a cell. The CLDSS scheme can also improve the fairness in terms of achievable throughput to users anywhere in the cell.