Fig. 1: Throughput variations of different algorithms in different scenarios.

a Throughput vs. network scale. Purification scheduling control (PSC) obtains the highest throughput for the whole network. When the network size is small, the throughput obtained by the threshold-based algorithm is higher than that of the Greedy algorithm because the number of hops between the source and destination nodes is relatively small. The fidelity requirement of the request may be achieved without purification, and the resources will be wasted if each link is purified. However, as the network size increases, the Threshold-based algorithm can obtain a lower throughput than the Greedy algorithm. b Throughput vs. S-D pairs. As the number of requests increases, more resources in the network can be used, resulting in an increase in the throughput obtained by all three algorithms. c Throughput vs. external link success probability. Regardless of whether the entanglement establishment probability is low or high, the PSC obtains the highest throughput, Greedy the second highest, and threshold-based obtains the lowest throughput. d Throughput vs. internal link success probability. As the entanglement swapping probability decreases, the throughput obtained by the PSC algorithm decreases faster than the other two algorithms. Because PSC can obtain more throughput than the other two algorithms when the entanglement swapping probability is not considered. However, when the entanglement swapping probability is considered, the PSC algorithm fails to establish a large number of entangled connections due to the failure of “internal connection” establishment. Nevertheless, PSC still achieves higher throughput than the other two algorithms. When the entanglement swapping probability is low, the threshold-based algorithm can achieve higher throughput than Greedy. Because the threshold-based algorithm spends fewer entanglement resources on entanglement purification than Greedy, it can establish more entanglement connections (most of which do not meet the fidelity requirement, and a few do). Still, the Greedy algorithm establishes entanglement connections that satisfy the fidelity requirement, so when there is an effect of entanglement swapping probability, Greedy is more likely to fail to establish entanglement connections that satisfy the fidelity requirement than threshold-based. When the entanglement swapping probability is high enough, the Greedy achieves higher throughput than threshold-based.