量子通信城域网设备部署及应用的研究

依托量子通信城域网对量子网关设备产生的密钥进行网络分发,确保两地之间密钥分配的绝对安全,为用户提供加/解密密钥,实现数据传输的安全可靠。同时,随着国家《GB/T22239-2019信息安全技术网络安全等级保护基本要求》等保2.0的发布,探索量子通信城域网的部署变得尤为重要。因此,以量子通信技术为出发点,通过对量子通信城域网网络架构、设备部署、安全防护以及在政务方面的应用研究,提出了量子城域网相应的部署方案。     

基于量子通信的邮件传输系统

传统电子邮件业务使用明文方式传送电子邮件，一旦窃听者捕获电子邮件报文，通过对邮件报文进行分析就能获取邮件内容。尽管当前存在一些解决方案能够提高电子邮件的安全性能，但只要窃听者拥有足够的计算能力，数据安全仍将无法保证。针对上述问题，本文提出了一种基于量子信道通信的邮件传输系统。在邮件传输过程中，将量子信道与传统信道结合使用，建立基于量子传输的SMTP协议和POP3协议。最终仿真结果表明，当邮件内容数据长度达到30比特时，量子邮件内容被窃取的可能性接近于0。因此，与传统的电子邮件传输系统相比，量子通信邮件传输系统能够保持较好的安全性能。     

量子密钥通信网信道复用方案研究

为降低量子密钥通信网建设成本,研究分析信道复用环境下的量子通信网络。针对目前主要的经典-量子信道复用方案,对较远波长隔离方案及同波段传输方案分别建立模型,仿真分析其系统性能。结果表明,较远波长隔离方案易于实现,在短距离通信中有良好的效果,可适用于短距离高密集局域网建设;同波段传输方案对信道隔离度有着较高要求,但更加符合经典光网络波段要求并有更远的通信距离,是量子密钥城域网建设的参考方案。     

一种新的量子纠缠无线中继模型及RQCP协议研究

无线量子通信是未来量子通信系统的重要组成部分,而量子纠缠中继则是无线量子通信的关键技术之一.然而,由于在无线信道上存在各种干扰和噪声,使得量子纠缠态远程传送的实现正面临很大的困难,为此,本文提出了基于移动终端和移动基站的两种量子纠缠中继方案,建立了量子无线通信网络的分层结构,给出了量子纠缠态无线传输的路由协议(RQCP).分析结果表明,即使在量子通信终端之间没有共享EPR纠缠对的情况下,本模型同样可以完成量子态的无线传输,并且其传输时延与链路的无线跳数无关.因此,从传输时延的观点来看,该中继方案和协议是最优的.     

基于团簇态的跨中心量子网络身份认证方案

利用连续两次量子隐形传态技术,提出了基于四粒子团簇态的跨中心量子网络身份认证方案,实现了分布式量子通信网络中对客户的身份认证。在该方案中,认证系统包括主服务器和客户端服务器,主服务器和客户端服务器之间通过共享四粒子团簇态为量子信道进行通信,客户所有的操作都在客户端服务器上进行,不直接与主服务器进行通信。身份认证全部由服务器根据量子力学原理进行,保证了认证方案的安全性。最后,对该方案进行了安全性分析。     

一种高效的量子秘密共享方案

利用量子安全直接通信和量子密集编码的思想,本文提出一个新的基于GHZ三重态的高效量子秘密共享(QSS)方案.利用量子相干性和一个公开的比特串K,Alice直接让Bob和Charlie共享其秘密消息,而不是首先与Bob和Charlie建立共享的联合密钥,再用联合密钥传输消息.该方案中平均消耗一个GHZ态可以共享两比特的经典信息.我们分别给出了无噪声信道和有噪声信道情形的安全性分析,并重点就量子直接秘密共享和量子安全直接通信之间的区别说明了协议中使用公开的K的必要性.     

量子保密通信技术及其在智慧城市中的应用研究

随着数字经济发展步伐加快，网络安全、数据安全问题变得更加重要，随时可能影响智慧城市发展，甚至危害社会安全和国家安全。QKD基于量子力学基本特性，能够提供无条件的安全性保证，与经典数据传输网络融合，解决量子保密通信和经典通信协同应用问题。研究了QKD应用的基础原理、关键技术和网络架构，探讨融合方法和创新应用方案，实现智慧城市更安全可靠的数据加密传输。     

基于Agent实现组播在广域网中的传输

针对目前Internet中大部分路由器不支持组播数据传输的问题，本文基于Agent技术提出了一种实现广域网内组播数据传输的方法。该方法使用了基于Agent的通信模型．组播会话中的每个成员通过其上运行的Agent实现数据收发；并将能够实施IP组播通信的网络范围看作是一个组播域，在每个组播域中自动选择一个Agent作为主Agent(MA)，组播域中的其他Agent为备份Agent(BA)；在组播域内利用IP组播进行数据传输，在组播域间利用主Agent之间的TCP连接进行数据传输．从而使得组播通信能够跨越路由器的障碑。此外还实现了BA向MA的自动升级．保证了组播会话的可靠性和连续性。     

量子安全直接通信协议综述及展望

量子安全直接通信是一种全新的高安全、高容量的量子通信模式,利用量子力学原理在量子信道中直接传输秘密信息,能够在真正意义上实现绝对安全,自首次被提出以来的近十年得到了飞速发展.详细综述了量子安全直接通信所采用的几种典型的量子直接通信协议和模型,主要包括基于纠缠光子对的两步通信协议和基于高维量子的通信协议.概述了量子安全直接通信的国内最新研究动态,简要评述了量子安全直接通信的发展趋势.     

基于RPR的高生存性网络

弹性分组环(RPR)技术定义了一种新型的媒体接入控制(MAC)层协议,采用了共享介质传输和空间复用协议以及低于50 ms的故障恢复保护的弹性机制,支持服务等级协定(SLA,Service Level Agreement),即插即用,基于MAC的高速交换,可承载具有突发性的IP业务,同时支持传统的语音传送,是未来城域网技术的重要发展方向.光纤技术的飞速发展使得RPR不再仅仅局限于城域网,还可以用于广域网.文章在基于RPR的低于50 ms的故障恢复保护的基础上,提出了具有高生存性的解决方案.     

Cooperative Caching Strategy in Mobile Ad Hoc Networks Based on Clusters

In this paper, we present a scheme, called Cluster Cooperative (CC) for caching in mobile ad hoc networks. In CC scheme, the network topology is partitioned into non-overlapping clusters based on the physical network proximity. For a local cache miss, each client looks for data item in the cluster. If no client inside the cluster has cached the requested item, the request is forwarded to the next client on the routing path towards server. A cache replacement policy, called Least Utility Value with Migration (LUV-Mi) is developed. The LUV-Mi policy is suitable for cooperation in clustered ad hoc environment because it considers the performance of an entire cluster along with the performance of local client. Simulation experiments show that CC caching mechanism achieves significant improvements in cache hit ratio and average query latency in comparison with other caching strategies.     

Video staging: a proxy-server-based approach to end-to-end videodelivery over wide-area networks

Real-time distribution of stored video over wide-area networks (WANs) is a crucial component of many emerging distributed multimedia applications. The heterogeneity in the underlying network environments is an important factor that must be taken into consideration when designing an end-to-end video delivery system. We present a novel approach to the problem of end-to-end video delivery over WANs using proxy servers situated between local-area networks (LANs) and a backbone WAN. A major objective of our approach is to reduce the backbone WAN bandwidth requirement. Toward this end, we develop an effective video delivery technique called video staging via intelligent utilization of the disk bandwidth and storage space available at proxy servers. Using this video staging technique, only part of a video stream is retrieved directly from the central video server across the backbone WAN whereas the rest of the video stream is delivered to users locally from proxy servers attached to the LANs. In this manner, the WAN bandwidth requirement can be significantly reduced, particularly when a large number of users from the same LAN access the video data. We design several video staging methods and evaluate their effectiveness in trading the disk bandwidth of a proxy server for the backbone WAN bandwidth. We also develop two heuristic algorithms to solve the problem of designing a multiple video staging scheme for a proxy server with a given video access profile of a LAN. Our results demonstrate that the proposed proxy-server-based approach provides an effective and scalable solution to the problem of the end-to-end video delivery over WANs     

A topology preserving cluster‐based channel assignment for wireless mesh networks

Wireless Mesh Networks (WMN) with multiple radios and multiple channels are expected to resolve the capacity limitation problem of simpler wireless networks. However, optimal WMN channel assignment (CA) is NP complete, and it requires an optimal mapping of available channels to interfaces mounted over mesh routers. Acceptable solutions to CA must minimize network interference and maximize available network throughput. In this paper, we propose a CA solution called as cluster‐based channel assignment (CBCA). CBCA aims at minimizing co‐channel interference yet retaining topology through non‐default CA. Topology preservation is important because it avoids network partitions and is compatible with single‐interface routers in the network. A ‘non‐default’ CA solution is desired because it uses interfaces over different channels and reduces medium contention among neighbors. To the best of our knowledge, CBCA is a unique cluster‐based CA algorithm that addresses topology preservation using a non‐default channel approach. The main advantage of CBCA is it runs in a distributed manner by allowing cluster heads to perform CA independently. CBCA runs in three stages, where first the WMN nodes are partitioned into clusters. The second stage performs binding of interfaces to neighbors and third stage performs CA. The proposed algorithm improves over previous work because it retains network topology and minimizes network interference, which in turn improves available network throughput. Further, when compared with two other CBCA algorithms, CBCA provides better performance in terms of improved network interference, throughput, delay, and packet delivery ratios when tested upon network topologies with various network densities and traffic loads. Copyright © 2014 John Wiley & Sons, Ltd.     

Data Transmission Strategy Based on Node Motion Prediction IoT System in Opportunistic Social Networks

With the rapid popularization of mobile smart devices in the IoT and the 5G environment, nodes’ requirements for network response speed are constantly increasing. Edge computing uses edge servers to perform simple processing when data is transmitted, increasing the response speed of devices and reducing the pressure on network traffic. However, the random movement of many nodes in an opportunistic social network easily leads to dynamic changes in the network structure and unstable transmission links. Therefore, this research proposes a data transmission strategy based on node motion prediction in opportunistic social networks (MPDTS). Any node will be assigned to a different cluster depending on how likely it is to meet other nodes. Messages are forwarded within and between clusters using different judgment indicators. This method effectively combines the connection between nodes, the node’s activity level, and sports characteristics successfully reduces the waste of resources for invalid message delivery. Simultaneously, it improves the possibility of message forwarding to the target node. Comparative experiments with several methods show that the MPDTS method has more outstanding performance.

     

A reliable transmission protocol for ZigBee-based wireless patient monitoring

Patient monitoring systems are gaining their importance as the fast-growing global elderly population increases demands for caretaking. These systems use wireless technologies to transmit vital signs for medical evaluation. In a multihop ZigBee network, the existing systems usually use broadcast or multicast schemes to increase the reliability of signals transmission; however, both the schemes lead to significantly higher network traffic and end-to-end transmission delay. In this paper, we present a reliable transmission protocol based on anycast routing for wireless patient monitoring. Our scheme automatically selects the closest data receiver in an anycast group as a destination to reduce the transmission latency as well as the control overhead. The new protocol also shortens the latency of path recovery by initiating route recovery from the intermediate routers of the original path. On the basis of a reliable transmission scheme, we implement a ZigBee device for fall monitoring, which integrates fall detection, indoor positioning, and ECG monitoring. When the triaxial accelerometer of the device detects a fall, the current position of the patient is transmitted to an emergency center through a ZigBee network. In order to clarify the situation of the fallen patient, 4-s ECG signals are also transmitted. Our transmission scheme ensures the successful transmission of these critical messages. The experimental results show that our scheme is fast and reliable. We also demonstrate that our devices can seamlessly integrate with the next generation technology of wireless wide area network, worldwide interoperability for microwave access, to achieve real-time patient monitoring.     

以用户为中心的可见光通信协作传输中训练资源分配算法

以用户为中心的可见光通信协作传输是近年来出现的新架构,这导致虚拟小区之间出现重叠。为避免导频污染问题,每个虚拟小区中的光接入点(AP)或者虚拟小区中选择相同AP的用户发送的训练序列应该是正交的。针对可见光通信中以用户为中心的协作网络,研究训练资源的正交分配问题,提出了一种新的导频分配算法,联合导频分配和用户选择问题,以期最大限度地增加虚拟小区内可被接入的用户数。分析和仿真结果表明,该导频分配方案可以有效改善导频污染问题,提高训练资源利用率,并且相比已有的导频分配方案,性能有所改进。     

End‐to‐end delay and packet drop rate performance for a wireless sensor network with a cluster‐tree topology

In this paper, we study the delay performance in a wireless sensor network (WSN) with a cluster‐tree topology. The end‐to‐end delay in such a network can be strongly dependent on the relative location between the sensors and the sink and the resource allocations of the cluster heads (CHs). For real‐time traffic, packets transmitted with excessive delay are dropped. Given the timeline allocations of each CH for local and inter‐cluster traffic transmissions, an analytical model is developed to find the distribution of the end‐to‐end transmission delay for packets originated from different clusters. Based on this result, the packet drop rate is derived. A heuristic scheme is then proposed to jointly find the timeline allocations of all the CHs in a WSN in order to achieve the minimum and balanced packet drop rate for traffic originated from different levels of the cluster tree. Simulation results are shown to verify the analysis and to demonstrate the effectiveness of the proposed CH timeline allocation scheme. Copyright © 2012 John Wiley & Sons, Ltd.     

Reducing packet loss with protection tunnel based rerouting

It is well-known that today’s inter-domain routing protocol, Border Gateway Protocol (BGP), converges slowly during network failures. During the convergence period, widespread temporary burst packet loss happens that may be caused by route loops or blackholes. In this paper, we present a Protection Tunnel based Rerouting (PTR)mechanism-a novel scheme for delivering packet continuously during period of convergence. PTR scheme pre-establishes protection tunnel among routers. Once the inter-domain link failed, routers could redirect those influenced packets along protection tunnel to a router that has a valid path to destination. Therefore, packets could be forwarded continuously even encountering fault links. The performances of PTR scheme are simulated. The results demonstrate that PTR scheme is more resilient to link failures than BGP. The cost caused by PTR scheme is very little and acceptable.     

A Tree-Based Data Collecting Network Structure for Wireless Sensor Networks

In a sensor network with a large number of densely populated sensor nodes, a single target of interest may be detected by multiple sensor nodes simultaneously. Data collected from the sensor nodes are usually highly correlated, and hence energy saving using in-network data fusion becomes possible. A traditional data fusion scheme starts with dividing the network into clusters, followed by electing a sensor node as cluster head in each cluster. A cluster head is responsible for collecting data from all its cluster members, performing data fusion on these data and transmitting the fused data to the base station. Assuming that a sensor node is only capable of handling a single node-to-node transmission at a time and each transmission takes T time-slots, a cluster head with n cluster members will take at least nT time-slots to collect data from all its cluster members. In this paper, a tree-based network structure and its formation algorithms are proposed. Simulation results show that the proposed network structure can greatly reduce the delay in data collection.