Request Scheduling in Quantum Networks

Abstract

Quantum networking is emerging as a new research area to explore the opportunities of inter-connecting quantum systems through end-to-end entanglement of qubits at geographical distance via quantum repeaters. A promising architecture has been proposed in the literature that decouples entanglement between adjacent quantum nodes / repeaters from establishing end-to-end paths by adopting a time slotted approach. Within this model, we destructure further end-to-end path establishment into two sub-problems: path selection and scheduling. The former is set to determine the best repeaters to connect two end nodes, provided that all their local entanglements have succeeded. On the other hand, scheduling is concerned with deciding which pairs of end nodes are served in the current time slot, while the others remain queued for later time slots. Unlike path selection, scheduling has not been investigated so far in the literature, particularly in presence of quantum noise, which makes both problems even more challenging. We propose to address it via a general framework of heuristic algorithms, for which we propose three illustrative instances with the objective of keeping the application delay small while achieving a good system utilization, in terms of high entanglement rate and fidelity of remotely entangled qubits. The system proposed is evaluated extensively via event-driven quantum network simulations, with noisy repeaters, in different node topologies under a Poisson arrival of requests from quantum applications. The results show the existence of a fundamental trade-off between system-and application-level metrics, such as fairness vs. entanglement and fidelity, which lays the foundations for further studies in this thriving research area.

Quantum Internet Protocol Stack: a Comprehensive Survey

“…As instance, let us focus on the simplest form of entangled resource constituted by an EPR pair. Each entangled node can take advantage of the entanglement -e.g., for transmitting a quantum state through quantum teleportation -as long as it coordinates with the other node [96]. Consequently, whether both the two nodes simultaneously decide to exploit the EPR pair, a proper Entanglement Access Control (EAC) protocol -with a goal reminiscent of medium access control (MAC) protocols in classical networks -must be in place for resolving any resource conflict.…”

Quality of Service in Quantum Networks

“…A complementary problem is that of deciding the order in which to assign paths, under the assumption that a set of requests are to be processed at the same time. In this area, we have proposed an iterative approach in [3] that attempts to balance an efficient use of resources with fair access to the network, while in [2] the authors have proposed a split approach where the achievable rates for all traffic flows are determined first, and then rates are mapped to paths. In this work we consider a pure online system, that is we assume that the requests of activating new traffic flows arrive one at a time and are served immediately (no batch execution, no queuing, no reserve list, .…”

First Request First Service Entanglement Routing Scheme for Quantum Networks

“…Therefore, the entanglement routing with active wavelength multiplexing schemes is desiderated for constructing entanglement distribution networks with various topologies [ 42 , 43 , 44 , 45 ]. In the meantime, existing quantum routing schemes [ 2 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ] are mainly focused on trusted node networks and quantum memory-assisted networks, and cannot be applied to quantum entanglement distribution networks, where time division multiplexing (TDM) and wavelength division multiplexing (WDM) techniques need to be adopted to forward entangled photons.…”