Quantum entanglement swapping can be used to establish reliable quantum remote transmission channel so as to realize transmission of quantum states. However, the highly stable quantum network is required in the quantum channels when using quantum entanglement swapping, otherwise it will waste a lot of entanglement resources. In order to save entanglement resources, we have to put forward a kind of quantum communication network transmission protocol based on packet switching, according to the theory of quantum teleportation. Firstly, the principle of packet switching in computer network is introduced. Next we describe the implementation process of quantum network transmission protocols which are based on entanglement swapping and packet switching. We then analyze the reliability, security and utilization rate of entanglement of the protocol we have proposed. And after that the quantitative relationship about the number of entanglement quantum states, the number of routers and link error rates are calculated. Finally, we compare these two transmission protocols. Simulation results show that the number of entanglement for these two protocols is equal without consideration of the link errors. When taking them into account, the packet switching transmission protocol can save numbers of entanglement resources obviously. In addition, with the increase of number of routers and the rise in link error rates, the quantum communication network transmission protocol based on packet switching will need less entanglement resources than that based on entanglement swapping. Therefore, when the quantum transmission network is not stable, the packet switching transmission protocol has a better transmission performance, and it can be applied to the future construction of quantum network.
Quantum entanglement swapping can be used to establish reliable quantum remote transmission channel so as to realize transmission of quantum states. However, the highly stable quantum network is required in the quantum channels when using quantum entanglement swapping, otherwise it will waste a lot of entanglement resources. In order to save entanglement resources, we have to put forward a kind of quantum communication network transmission protocol based on packet switching, according to the theory of quantum teleportation. Firstly, the principle of packet switching in computer network is introduced. Next we describe the implementation process of quantum network transmission protocols which are based on entanglement swapping and packet switching. We then analyze the reliability, security and utilization rate of entanglement of the protocol we have proposed. And after that the quantitative relationship about the number of entanglement quantum states, the number of routers and link error rates are calculated. Finally, we compare these two transmission protocols. Simulation results show that the number of entanglement for these two protocols is equal without consideration of the link errors. When taking them into account, the packet switching transmission protocol can save numbers of entanglement resources obviously. In addition, with the increase of number of routers and the rise in link error rates, the quantum communication network transmission protocol based on packet switching will need less entanglement resources than that based on entanglement swapping. Therefore, when the quantum transmission network is not stable, the packet switching transmission protocol has a better transmission performance, and it can be applied to the future construction of quantum network.
By using quantum packet transmission technology in large scale quantum communication networks, the throughput of transmission node, network link utilization, and the anti-interference performance of communication can be effectively improved. However, the fast transmission of quantum packets is closely related to the performance of router. The bottleneck of the router performance will seriously affect the scalability of the network and the transmission efficiency of the link. In order to reduce the number of quantum packet queues in nodes of the quantum communication network and to reduce the transmission delay of quantum packets, firstly, according to the classical computer communication network structure, in our paper, we divide the quantum communication network into quantum local area network, quantum metropolitan area network and quantum wide area network. Secondly, the quantum packet format and the quantum cluster format compatible with the packet format in the computer network are determined. Then, a quantum information packet transmission scheme based on the hierarchy is proposed, to realize the end-to-end transmission of quantum information. In our scheme, the quantum packets are divided into quantum packet header information and quantum data information. Quantum dense coding mode is used to transmit the quantum packet header information, while the quantum data information uses quantum teleportation to transmit. First, the quantum packets are sent to the router of the quantum local area network at source address, then the quantum LAN router relay the packets to the quantum metropolitan area network router, the router here makes the quantum packets into quantum cluster according to destination address. Quantum clusters are transmitted in the quantum metropolitan area network and quantum wide area network, ending in the quantum metropolitan area network routing. After the quantum clusters are decomposed, they are sent to the destination address through the local area network router of each quantum packet.We analyze the number of quantum entanglement pairs and the total transmission time in our scheme. The results show that the more the routers by the quantum packet and the quantum cluster are, the more the number of quantum entanglement pairs required by the transmission of a certain quantum packet is. When the number of routers is certain, the number of entanglement pairs required in the transmission process of quantum packet and quantum cluster depends on the number of quantum packets. Finally, the theoretical analysis and calculation are carried out by Matlab simulation, the results show that hierarchical quantum packet information transmission scheme can effectively reduce the transmission time of quantum packet information in the quantum communication network, and the reduced time is related to the quantum router performance and the number of quantum packets to send: the more the number of quantum packets to send, the longer the length of packet processing time needs is and the more obvious the advantage of our scheme is. Therefore, the proposed scheme in this paper is suitable for the construction of large scale quantum communication networks.
The distributed wireless quantum communication network (DWQCN) has a distributed network topology and transmits information by quantum states. In this paper, we present the concept of the DWQCN and propose a system scheme to transfer quantum states in the DWQCN. The system scheme for transmitting information between any two nodes in the DWQCN includes a routing protocol and a scheme for transferring quantum states. The routing protocol is on-demand and the routing metric is selected based on the number of entangled particle pairs. After setting up a route, quantum teleportation and entanglement swapping are used for transferring quantum states. Entanglement swapping is achieved along with the process of routing set up and the acknowledgment packet transmission. The measurement results of each entanglement swapping are piggybacked with route reply packets or acknowledgment packets. After entanglement swapping, a direct quantum link between source and destination is set up and quantum states are transferred by quantum teleportation. Adopting this scheme, the measurement results of entanglement swapping do not need to be transmitted specially, which decreases the wireless transmission cost and transmission delay.
Traditional virtual private networks（ VPNs） are conditional security. In order to ensure the security and confidentiality of user data transmission,a model of quantum VPN based on Internet protocol security（ IPSec）protocol is proposed. By using quantum keys for key distribution and entangled particles for identity authentication in the network,a secure quantum VPN is relized. The important parameters affecting the performance of the VPN was analyzed. The quantitative relationship between the security key generation rate,the quantum bit error rate（ QBER） and the transmission distance was obtained. The factors that affect the system throughput were also analyzed and simulated. Finally,the influence of the quantum noise channel on the entanglement swapping was analyzed. Theoretical analysis and simulation results show that,under a limited number of decoy states,with the transmission distance increased from 0 to 112. 5 km,the secure key generation rate was reduced from 5. 63 × 10-3 to 1. 22 × 10-5. When the number of decoy states is fixed,the QBER increases dramatically with the increase of the transmission distance,and the maximum reaches 0. 393. Analysis shows that various factors in communication have a significant impact on system throughput. The generation rate of the effective entanglement photon pairs have decisive effect on the system throughput. Therefore,in the process of quantum VPN communication,various parameters of the system should be properly adjusted to communicate within a safe transmission distance,which can effectively improve the reliability of the quantum communication system.
This paper puts forward a quantum signaling switch model. The quantum signaling switch consists of a classical information control module, an exchange control module and a quantum exchange module. Classical control module transmits the initial entangled state information to the entanglement measurement and switching unit and updates the routing information. Exchange control module will choose the path, and is ready for the distribution channel of the entanglement photons. The quantum exchange module generates quantum entanglement pairs, measures the Bell state and achieves entanglement swapping. Quantum signaling switches can realize multi-user communication and local area network communication. Through the performance analysis and simulation of the switch, the results show that the switch is simple in structure, secure and easy to expand; also the time delay is small. This will be helpful for the construction of the quantum communication network.
Aiming at the quantum signalling repeater network model for multi-user,environment quantum noises effect on remote transmission of signalling was studied.A kind of quantum signaling repeater strategy was purposed after the theory of quantum swapping being analyzed.Then a bus network model was put forward and the success rate of long distance quantum signaling transmission was simulated.The results show that long distance signaling transmission has a close relationship with the noise power spectral density,transmission distance and repeater times.When noise power spectral density is constant and there is no repeater during the transmission process,the success rate declines like plesio-flat-parabola with increasing of the transmission distance.On the condition of constant noise power spectral density and constant transmission distance,the success rate increases obviously while the repeater times is increasing.Therefore,on the behalf of reliable quantum signaling transmission the transmission distance and repeater times should be designed properly under the circumstance of constant background noise.
Large-scale quantum networks with thousands of nodes require scalable network protocols and physical hardware to realize. In this paper, we introduce packet switching as a paradigm for quantum data transmission in both future and near-term quantum networks. We propose a classical-quantum data frame structure and explore methods of frame generation and processing. Further, we present conceptual designs for a quantum reconfigurable optical add-drop multiplexer to realize the proposed transmission scheme. Packet switching allows for a universal design for a next-generation Internet where classical and quantum data share the same network protocols and infrastructure. In this quantum networking paradigm, entanglement distribution, as with quantum key distribution, is an application built on top of the quantum network rather than as a network designed especially for those purposes. For analysis of the network model, we simulate the feasibility of quantum packet switching for some preliminary models of quantum key and entanglement distribution. Finally, we discuss how our model can be integrated with other network models toward a realization of the quantum Internet.