Quantum communication is the interdisciplinary science of quantum mechanics and telecommunication theory. It has advantages of perfect information security and high efficiency in transmission. In recent years, the theoretical and experimental results show that quantum communication systems have the superiority over the traditional communication systems. Quantum communication systems are hopeful for solving the information security problems that everyone is facing today, therefore, they possess broad application prospects and are forming a research hotspot of the telecommunications field currently. On the other hand, Voice over Internet Protocol (VoIP) is the method to transmit the digitized packet voice in Internet around the world. The advantages of VoIP are that it can carry voice, data, video, telephone conference, electronic commerce, and electronic mail economically. VoIP can realize the information storage and retransmission easily and flexibly. However, VoIP also encounters the problem of information security. We are trying to combine the quantum communications network and the VoIP system together and build a brand new network named quantum VoIP network which combines the advantages of both quantum communications and VoIP. The data packets may be delayed and lost in a queue up with a router due to the congestion and link failure during the transmission of quantum information. In order to ensure the performance of quantum VoIP system, the routing optimization strategies are proposed in the paper. The relay technology based on entanglement swapping is adopted. The multiuse quantum communications are realized by giving priority to the quantum channels with the least relay nodes. Theoretical analysis and simulation results show that when the data transmission links are fail to work properly and routers are in congestion, adopting the routing optimization strategies in M/M/m queuing system with the bit error rate (BER) of quantum bit setting to be 0.2 and the number of common channels increasing from 4 to 8,, the percentage of call failure in quantum communication network decreases from 0.25 to 0.024, and the maximum throughput of quantum networks increases from 64 kbps to 132 kbps. In comparison, when the number of common channels is set to be 4 andthe BER of the quantum bit is from 0.3 to 0.1, the maximum throughput of quantum networks increases from 41 kbps to 140 kbps. Thus it can be concluded that the routing optimization strategies proposed in this paper can improve the performance of quantum VoIP system significantly.
Quantum communication is the interdisciplinary science of quantum mechanics and telecommunication theory. It has advantages of perfect information security and high efficiency in transmission. In recent years, the theoretical and experimental results show that quantum communication systems have the superiority over the traditional communication systems. Quantum communication systems are hopeful for solving the information security problems that everyone is facing today, therefore, they possess broad application prospects and are forming a research hotspot of the telecommunications field currently. On the other hand, Voice over Internet Protocol (VoIP) is the method to transmit the digitized packet voice in Internet around the world. The advantages of VoIP are that it can carry voice, data, video, telephone conference, electronic commerce, and electronic mail economically. VoIP can realize the information storage and retransmission easily and flexibly. However, VoIP also encounters the problem of information security. We are trying to combine the quantum communications network and the VoIP system together and build a brand new network named quantum VoIP network which combines the advantages of both quantum communications and VoIP. The data packets may be delayed and lost in a queue up with a router due to the congestion and link failure during the transmission of quantum information. In order to ensure the performance of quantum VoIP system, the routing optimization strategies are proposed in the paper. The relay technology based on entanglement swapping is adopted. The multiuse quantum communications are realized by giving priority to the quantum channels with the least relay nodes. Theoretical analysis and simulation results show that when the data transmission links are fail to work properly and routers are in congestion, adopting the routing optimization strategies in M/M/m queuing system with the bit error rate (BER) of quantum bit setting to be 0.2 and the number of common channels increasing from 4 to 8,, the percentage of call failure in quantum communication network decreases from 0.25 to 0.024, and the maximum throughput of quantum networks increases from 64 kbps to 132 kbps. In comparison, when the number of common channels is set to be 4 andthe BER of the quantum bit is from 0.3 to 0.1, the maximum throughput of quantum networks increases from 41 kbps to 140 kbps. Thus it can be concluded that the routing optimization strategies proposed in this paper can improve the performance of quantum VoIP system significantly.
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.
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.
In recent years, quantum communication networks have emerged as a promising alternative to classical communication networks for the transmission of quantum information. One of the challenges for achieving optimal performance in quantum communication networks is the efficient routing of quantum signals across multiple paths. To address this, a variety of routing protocols have been proposed, including multi-path routing protocols. Multi-path routing involves sending a quantum signal through multiple distinct paths simultaneously to reduce delays in the transmission of quantum information. By distributing the quantum information over multiple paths, this approach can provide significant performance improvements, including reduced latency and higher throughput. In addition, multi-path routing can enable new possibilities for the security of quantum communication networks, such as more secure entanglement swapping protocols and improved protection against eavesdropping. In this paper, we investigate the performance of multi-path routing protocols in multi-node quantum communication networks. We consider two approaches to multi-path routing, a basic routing approach based on shortest path optimization, and a more advanced approach based on graph partitions. We evaluate the performance of these protocols in a range of multi-node networks, with focus on the trade-off between latency and throughput. The results show that multi-path routing yields significant performance improvements in such networks and provides an efficient way for routing quantum signals across multiple paths.
According to quantum mechanics,quantum communication has the advantages in information security than the classical communication,and so it has been studied as new hot spot in communication field.Mobile quantum communication is one of the most important parts in the future quantum communication.Quantum entanglement relay is one of the key technologies in mobile quantum communication systems.However,there are so many kinds of interference and noise in wireless channel,that it is very hard to realize the relay of the quantum states.To address and solve the problem,the two quanta relay schemes based on mobile terminals and base stations are presented firstly.The layered structure of wireless quantum communication and the routing protocol of the quantum states transmission in wireless(QMRP) are presented also.Theory analysis results show that the scheme above can transmit quanta states with no EPR pairs shared by source and objective nodes,and the time delay in transmission has nothing to do with the number of wireless hopping.It proves that the model and scheme are optimal.
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 secure direct communication, as an important branch of quantum communication, possesses strict information-theoretic security and can achieve secure communication in channel environments with noise interference and eavesdropping threats. As voice communication is the most fundamental and widespread communication method in daily life, guaranteeing its security and efficiency has become an important research topic in current communication technology. One-way quantum secure direct communication technology can build an efficient and reliable security barrier for voice communication services, effectively preventing the leakage of private information in voice communication. This paper proposes a duplex voice communication scheme based on one-way quantum secure direct communication. By adopting a method combining multi-task parallel processing and stream processing, the communication rate and transmission delay performance of the system are significantly improved. Relying on quantum secure direct communication technology and the one-time-key encryption channel within the system, duplex voice communication is achieved securely. The real-time temperature drift compensation algorithm is introduced to ensure the long-term stable operation of the system. At the same time, through the real-time temperature drift prediction mechanism, the strategy selection during the call process is optimized to ensure the quality of the voice communication. To verify the feasibility and performance of this scheme, a one-way quantum secure direct communication duplex voice communication system was built in the laboratory environment, and comprehensive performance indicator tests were conducted. The test results show that the constructed one-way quantum secure direct communication system can fully meet the performance requirements of duplex voice communication. The realization of this system successfully achieves the goal of secure and efficient quantum voice communication, laying an important technical foundation for further expanding the practical application scenarios of quantum communication technology and promoting the industrialization development of quantum communication.