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Block-free optical quantum Banyan network based on quantum state fusion and fission

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Chinese Physics B 2014年第12期23卷 71-77页

作者：朱畅华孟艳红权东晓赵楠裴昌幸 State Key Laboratory of Integrated services networks Xidian University

Optical switch fabric plays an important role in building multiple-user optical quantum communication *** to its self-routing property and low complexity, a banyan network is widely used for building switch fabric. While,there is no efficient way to remove internal blocking in a banyan network in a classical way, quantum state fusion, by which the two-dimensional internal quantum states of two photons could be combined into a four-dimensional internal state of a single photon, makes it possible to solve this problem. In this paper, we convert the output mode of quantum state fusion from spatial-polarization mode into time-polarization mode. By combining modified quantum state fusion and quantum state fission with quantum Fredkin gate, we propose a practical scheme to build an optical quantum switch unit which is block free. The scheme can be extended to building more complex units, four of which are shown in this paper.

关键词： optical switch fabric quantum state fusion quantum Fredkin gate linear optics

Generation and characterization of orthogonal FH sequences for the cognitive network

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Science China(Information Sciences) 2015年第2期58卷 140-150页

作者： GUAN Lei LI Zan SI JiangBo HUANG YangChao State Key Laboratory of Integrated services networks Xidian University

The existing orthogonal frequency hopping(FH) sequence cannot support the high throughput and high spectrum efficient cognitive FH(CFH) network due to its small family size, high computational complexity and short period. To overcome these disadvantages, this paper investigates the generation of the orthogonal FH sequence and analyzes its multiple accessibility performance based on the CFH frequency division multipleaccess(FDMA) network model. By the random mapping and cyclical shift replacement(CSR) scheme, a large family size of orthogonal FH sequence with dynamic frequency slot number is generated. In this case, the external interference could be eliminated by avoiding the interfered frequencies, and blocking mutual interference incurred for the packet by the orthogonal frequencies. Moreover, the theoretical relationships of the throughput and transmission delay with respect to the user number and the packet arrival rate are given, which shows that our proposed orthogonal FH sequence could support high throughput and short packet transmission delay in CFH-FDMA network. The simulation results validate our theoretical analysis of the CFH-FDMA network performance, and show that our proposed sequence outperforms the widely used no hit zone FH sequences in terms of uniformity, randomness, Hamming correlation, complexity and sensitivity, etc.

关键词： cognitive frequency hopping orthogonal frequency hopping sequence frequency hopping network frequency division multiple access throughput

Neighbor Detection-Based Spectrum Sensing Algorithm in Distributed Cognitive Radio networks

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Chinese Journal of Electronics 2017年第2期26卷 399-406页

作者： PEI Qingqi LI Hongning LIU Xianjun State Key Laboratory of Integrated services networks Xidian University

Security issues of spectrum sensing have drawn a lot of attentions in Cognitive radio networks(CRNs).Malicious users can mislead the network to make wrong decision about the states of channels by tampering spectrum sensing *** defense against Spectrum sensing data falsification(SSDF) attack,we propose a neighbor detection-based spectrum sensing algorithm in distributed CRNs,which can detect attackers with the help of neighbors during spectrum sensing to improve the accuracy of decision *** proposed scheme can also guarantee the connectivity of the *** results illustrate that the proposed scheme can defense against SSDF attacks effectively and reach the unified information of spectrum sensing data.

关键词： Cognitive radio networks(CRNs) Spectrum sensing data falsification(SSDF) Neighbor detection Connectivity

Heralded linear optical quantum Fredkin gate based on one auxiliary qubit and one single photon detector

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Chinese Physics B 2014年第8期23卷 362-367页

作者：朱畅华曹鑫权东晓裴昌幸 State Key Laboratory of Integrated services networks Xidian University

Linear optical quantum Fredkin gate can be applied to quantum computing and quantum multi-user communication networks. In the existing linear optical scheme, two single photon detectors （SPDs） are used to herald the success of the quantum Fredkin gate while they have no photon count. But analysis results show that for non-perfect SPD, the lower the detector efficiency, the higher the heralded success rate by this scheme is. We propose an improved linear optical quantum Fredkin gate by designing a new heralding scheme with an auxiliary qubit and only one SPD, in which the higher the detection efficiency of the heralding detector, the higher the success rate of the gate is. The new heralding scheme can also work efficiently under a non-ideal single photon source. Based on this quantum Fredkin gate, large-scale quantum switching networks can be built. As an example, a quantum Bene~ network is shown in which only one SPD is used.

关键词： quantum Fredkin gate linear optics quantum switching network

Quantum communication for satellite-to-ground networks with partially entangled states

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Chinese Physics B 2015年第2期24卷 53-61页

作者：陈娜权东晓裴昌幸杨宏 State Key Laboratory of Integrated services networks Xidian University

To realize practical wide-area quantum communication,a satellite-to-ground network with partially entangled states is developed in this *** efficiency and security reasons,the existing method of quantum communication in distributed wireless quantum networks with partially entangled states cannot be applied directly to the proposed quantum *** on this point,an efficient and secure quantum communication scheme with partially entangled states is *** our scheme,the source node performs teleportation only after an end-to-end entangled state has been established by entanglement swapping with partially entangled ***,the security of quantum communication is *** destination node recovers the transmitted quantum bit with the help of an auxiliary quantum bit and specially defined unitary *** calculations and simulation analyses show that the probability of successfully transferring a quantum bit in the presented scheme is *** addition,the auxiliary quantum bit provides a heralded mechanism for successful *** on the critical components that are presented in this article an efficient,secure,and practical wide-area quantum communication can be achieved.

关键词： satellite-to-ground quantum communication network partially entangled states entanglementswapping quantum teleportation

A credible traffic prediction method based on self-supervised causal discovery

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Science China(Information Sciences) 2024年第5期67卷 244-258页

作者： Dan WANG Yingjie LIU Bin SONG State Key Laboratory of Integrated services networks Xidian University

Next-generation wireless network aims to support low-latency, high-speed data transmission services by incorporating artificial intelligence(AI) technologies. To fulfill this promise, AI-based network traffic prediction is essential for pre-allocating resources, such as bandwidth and computing power. This can help reduce network congestion and improve the quality of service(QoS) for users. Most studies achieve future traffic prediction by exploiting deep learning and reinforcement learning, to mine spatio-temporal correlated variables. Nevertheless, the prediction results obtained only by the spatio-temporal correlated variables cannot reflect real traffic changes. This phenomenon prevents the true prediction variables from being inferred, making the prediction algorithm perform poorly. Inspired by causal science, we propose a novel network traffic prediction method based on self-supervised spatio-temporal causal discovery(SSTCD). We first introduce the Granger causal discovery algorithm to build a causal graph among prediction variables and obtain spatio-temporal causality in the observed data, which reflects the real reasons affecting traffic ***, a graph neural network(GNN) is adopted to incorporate causality for traffic prediction. Furthermore,we propose a self-supervised method to implement causal discovery to to address the challenge of lacking ground-truth causal graphs in the observed data. Experimental results demonstrate the effectiveness of the SSTCD method.

关键词： wireless network traffic prediction causal discovery self-supervised

A long-distance quantum key distribution scheme based on pre-detection of optical pulse with auxiliary state

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Chinese Physics B 2015年第5期24卷 252-256页

作者：权东晓朱畅华刘世全裴昌幸 State Key Laboratory of Integrated services networks Xidian University

We construct a circuit based on PBS and CNOT gates, which can be used to determine whether the input pulse is empty or not according to the detection result of the auxiliary state, while the input state will not be changed. The circuit can be treated as a pre-detection device. Equipping the pre-detection device in the front of the receiver of the quantum key distribution （QKD） can reduce the influence of the dark count of the detector, hence increasing the secure communication distance significantly. Simulation results show that the secure communication distance can reach 516 km and 479 km for QKD with perfect single photon source and decoy-state QKD with weak coherent photon source, respectively.

关键词： quantum key distribution pre-detection secure communication distance decoy state

Polarization-Encoding-Based Measurement-Device-Independent Quantum Key Distribution with a Single Untrusted Source

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Chinese Physics Letters 2016年第10期33卷 3-6页

作者：刘传起朱畅华王连辉张林曦裴昌幸 State Key Laboratory of Integrated services networks Xidian University

Measurement-device-independent quantum key distribution （MDI-QKD） can be immune to all detector side- channel attacks and guarantee the information-theoretical security even with uncharacterized single photon detectors. MDI-QKD has been demonstrated in both laboratories and field-tests by using attenuated lasers combined with the decoy-state technique. However, it is a critical assumption that the sources used by legitimate participants are trusted in MDI-QKD. Hence, it is possible that a potential security risk exists. Here we propose a new scheme of polarization-encoding-based MDI-QKD with a single untrusted source, by which the complexity of the synchronization system can be reduced and the success rate of the Bell-state measurement can be improved. Meanwhile, the decoy-state method is employed to avoid the security issues introduced by a non-ideal single photon source. We also derive a security analysis of the proposed system. In addition, it seems to be a promising candidate for the implementation for QKD network in the near future.

关键词： QKD MDI Polarization-Encoding-Based Measurement-Device-Independent Quantum Key Distribution with a Single Untrusted Source of in for been is that with

On the designing principles and optimization approaches of bio-inspired self-organized network: a survey

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Science China(Information Sciences) 2013年第7期56卷 5-32页

作者： ZHANG ZhongShan HUANGFU Wei LONG KePing ZHANG Xu LIU XiaoYuan ZHONG Bin Institute of advanced Network Technology and New services (ANTS) University of Science and Technology Beijing (USTB) Beijing Engineering and Technology Center for Convergence networks and Ubiquitous services University of Science and Technology Beijing (USTB)

A plethora of studies on self-organization has been carried out in broad areas including chemistry, biology, astronomy, medical science, telecommunications, etc., in both academia and industry. Following the studies on swarm intelligence observed in social species, the artificial self-organized systems are expected to exhibit some intelligent features (e.g., flexibility, robustness, decentralized control, self-evolution, etc.) that may have made social species so successful in the biosphere. In this paper, the application of swarm intelligence in communications networks will be studied, and we survey different aspects of bio-inspired mechanisms and examine various algorithms that have been proposed to improve the performance of artificial systems. Some fundamental self-organized networking (SON) mechanisms, designing principles and optimization approaches for artificial systems will then be investigated, followed by some well-known bio-inspired algorithms (e.g., cooperation, division of labor, distributed network synchronization, load balancing, etc.) as well as their applications to the maintenance/operation/optimization of artificial systems being analyzed. Besides, some new emerging technologies, such as the Self-X capabilities and cognitive machine-to-machine (M2M) optimization for the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE)/LTE-advanced systems, are also surveyed. Finally, the remaining challenges to be faced in designing the future heterogeneous systems will be discussed.

关键词： self-organized networking heterogeneous cognitive radio bio-inspired swarm intelligence decentralized load balancing cooperation