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Dual-Threshold Based Secure On-Off Transmission Scheme for Dense HCNs with Imperfect CSI

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China Communications 2019年第3期16卷 132-142页

作者： Yunjia Xu Kaizhi Huang Yi Zou Xin Hu National Digital Switching System engineering & technological research center

In this paper, we propose a dual-threshold based secure On-Off transmission scheme, where signals are transmitted only if the channel condition can guarantee secure and reliable communication. First, we present a dynamic access strategy to increase access efficiency, which provides an access region for the intended user. Then, we propose an emission control policy to transmit signals according to the current channel condition, which declines the influence of channel estimation errors and guarantees qualities of communication links. Furthermore, we give a comprehensive performance analysis for the proposed scheme in terms of connection outage probability(COP) and secrecy outage probability(SOP), and present a dual-threshold optimization model to further support the performance. Numerical results verify that the secure On-Off transmission scheme can increase the system secure energy efficiency and guarantee reliable and secure communication.

关键词： physical layer security imperfect CSI dense heterogeneous cellular networks On-Off transmission secure energy efficiency

A Self-Adaptive Programming Mechanism for Reconfigurable Parsing and Processing

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China Communications 2016年第S1期13卷 87-97页

作者： DUAN Tong SHEN Juan WANG Peng LIU Shiran National Digital Switching System engineering & technological research center

In this paper, we present a self-adaptive programming mechanism(SAP) that targets programming hardware devices of reconfigurable parsing and processing. The SAP programming system locates in software of network data plane and has three features:(1) programmable packet parsing: the packet header format can be customized and new header type can be added;(2) reconfigurable packet processing: the match fields to be handled in each match table can be specified;(3) function-adaptive control: any function control systems can determine the packet processing flow independently without the need of knowing the specifics of the underlying hardware. Finally, we implement a prototype on NetF PGA-10 G together with two representative function control systems(router and Open Flow switch) to demonstrate how SAP works. We believe the data plane of reconfigurable parsing and processing will lead to future switches that provide greater flexibility, and unlock the potential of network function innovation.

关键词： programming mechanism selfadaptive reconfigurable network data plane Net FPGA

Design and Implementation of an SDN-Enabled DNS Security Framework

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China Communications 2019年第2期16卷 233-245页

作者： Zhenpeng Wang Hongchao Hu Guozhen Cheng National Digital Switching System engineering and technological research center

The Domain Name System(DNS) is suffering from the vulnerabilities exploited to launch the cache poisoning attack. Inspired by biodiversity, we design and implement a non-intrusive and tolerant secure architecture Multi-DNS(MDNS) to deal with it. MDNS consists of Scheduling Proxy and DNS server pool with heterogeneous DNSs in it. And the Scheduling Proxy dynamically schedules m DNSs to provide service in parallel and adopts the vote results from majority of DNSs to decide valid replies. And benefit from the centralized control of software defined networking(SDN), we implement a proof of concept for it. Evaluation results prove the validity and availability of MDNS and its intrusion/fault tolerance, while the average delay can be controlled in 0.3s.

关键词： DNS cache poisoning attack software defined networking moving target defense dynamic heterogeneous redundant

Uncovering network traffic anomalies based on their sparse distributions

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Science China(Information Sciences) 2014年第9期57卷 256-266页

作者： CHENG GuoZhen CHEN HongChang CHENG DongNian ZHANG Zhen LAN JuLong National Digital Switching System engineering and technological research center

Characterizing network traffic with higher-dimensional features results in increased complexity of most detectors and classifiers for identifying traffic *** key observations from existing studies confirm that network anomalies are typically distributed in a sparse way,with each anomaly essentially characterized by its lower-dimensional *** on this important finding,we exploit sparsity in designing a novel detection method for anomalies that ignores redundancies that are dynamically filtered from the feature sets and accurately classifies *** of our method with three well known techniques shows a10%improvement in accuracy with an O(n)complexity of the classifier.

关键词： anomaly detection feature filtering multi-resolution analysis sparse distribution

Physical Layer Security of Multi-hop Aided Downlink MIMO heterogeneous Cellular Networks

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China Communications 2016年第S2期13卷 120-130页

作者： Xiaohui Qi Kaizhi Huang Zhihao Zhong Xiaolei Kang Zhou Zhong National Digital Switching System engineering & technological research center

This study investigates physical layer security in downlink multipleinput multiple-output(MIMO) multi-hop heterogeneous cellular networks(MHCNs),in which communication between mobile users and base stations(BSs) is established by a single or multiple hops,to address the problem of insufficient security performance of MIMO heterogeneous cellular ***,two-dimensional homogeneous Poisson point processes(HPPPs) are utilized to model the locations of K-tier BSs in MIMO MHCNs and receivers,including those of legitimate users and ***,based on the channel gain distribution and the statistics property of HPPP,the achievable ergodic rates of the main and eavesdropper channels in direct and ad hoc links are derived,***,the secrecy coverage probability and the achievable ergodic secrecy throughput of downlink MIMO MHCNs are explored,and their expressions are ***,the correctness of the theoretical derivation is verified through Monte Carlo simulations.

关键词： multi-hop heterogeneous cellular networks secrecy coverage probability stochastic geometry secrecy throughput

Dynamic hybrid multimedia distribution scheme based on network reconfiguration

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Science China(Information Sciences) 2014年第10期57卷 107-116页

作者： DONG Fang HU YuXiang LAN JuLong National Digital Switching System engineering and technological research center

This paper addresses a key challenge in the design and implementation of multimedia distribution systems so that users can experience good performance with minimal operational costs. In current structures,the conflict between network architectures and service provision causes a decline in users’ expectations of quality. Network reconfiguration provides a feasible solution for dynamic distribution as a primitive for both quality and efficiency. In this paper, we first present a scheme for a layer-based hybrid multimedia distribution system LHMDS, and then introduce a dynamic sliding push-delivery mechanism based on reconfiguration of the distribution of hotspot files. The LHMDS adopts a unique structure with hybrid channels, including broadcast and unicast ones, and adjusts its distribution topology according to the congestion status, thereby pushing hotspot files dynamically. The mechanism dynamically pushes files to upper or lower network layers depending on the network status while distributing hotspot files by broadcast channels and other files by unicast *** guarantees service quality as well as improving resource utilization. Finally, we validate the feasibility and performance of the scheme through a simulation.

关键词： network reconfiguration hybrid distribution dynamic sliding push-delivery

Fast local reconstruction by selective backprojection for low dose in dental computed tomography

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Chinese Physics C 2014年第10期38卷 117-125页

作者：闫镔邓林韩玉张峰汪先超李磊 National Digital Switching System engineering and technological research center

The high radiation dose in computed tomography （CT） scans increases the lifetime risk of cancer, which becomes a major clinical concern. The backprojection-filtration （BPF） algorithm could reduce the radiation dose by reconstructing the images from truncated data in a short scan. In a dental CT, it could reduce the radiation dose for the teeth by using the projection acquired in a short scan, and could avoid irradiation to the other part by using truncated projection. However, the limit of integration for backprojection varies per PI-line, resulting in low calculation efficiency and poor parallel performance. Recently, a tent BPF has been proposed to improve the calculation efficiency by rearranging the projection. However, the memory-consuming data rebinning process is included. Accordingly, the selective BPF （S-BPF） algorithm is proposed in this paper. In this algorithm, the derivative of the projection is backprojected to the points whose x coordinate is less than that of the source focal spot to obtain the differentiated backprojection. The finite Hilbert inverse is then applied to each PI-line segment. S-BPF avoids the influence of the variable limit of integration by selective backprojection without additional time cost or memory cost. The simulation experiment and the real experiment demonstrated the higher reconstruction efficiency of S-BPF.

关键词： local reconstruction dental CT selective backprojection short scan

An Effective and Scalable VM Migration Strategy to Mitigate Cross-VM Side-Channel Attacks in Cloud

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China Communications 2019年第4期16卷 151-171页

作者： Chao Yang Yunfei Guo Hongchao Hu Wenyan Liu Yawen Wang National Digital Switching System engineering & technological research center

Co-residency of virtual machines(VMs) of different tenants on the same physical platform would possibly lead to cross-VM side-channel attacks in the cloud. While most of current countermeasures fail for real or immediate deployment due to their requirement for modification of virtualization structure, we adopt dynamic migration, an inherent mechanism of the cloud platform, as a general defense against this kind of threats. To this end, we first set up a unified practical information leakage model which shows the factors affecting side channels and describes the way they influence the damage due to side-channel attacks. Since migration is adopted to limit the time duration of co-residency, we envision this defense as an optimization problem by setting up an Integer Linear Programming(ILP) to calculate optimal migration strategy, which is intractable due to high computational complexity. Therefore, we approximate the ILP with a baseline genetic algorithm, which is further improved for its optimality and scalability. Experimental results show that our migration-based defense can not only provide excellent security guarantees and affordable performance cost in both theoretical simulation and practical cloud environment, but also achieve better optimality and scalability than previous countermeasures.

关键词： side-channel attacks information leakage virtual machine migration genetic algorithm

An Approach for Network Function Combination Based on Least Busy Placement Algorithm

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China Communications 2016年第S1期13卷 167-176页

作者： XIE Lijun JIANG Yiming WANG Binqiang XIONG Gang CHENG Guozhen National Digital Switching System engineering & technological research center

Recently, integrating Softwaredefined networking(SDN) and network functions virtualization(NFV) are proposed to address the issue that difficulty and cost of hardwarebased and proprietary middleboxes management. However, it lacks of a framework that orchestrates network functions to service chain in the network cooperatively. In this paper, we propose a function combination framework that can dynamically adapt the network based on the integration NFV and SDN. There are two main contributions in this paper. First, the function combination framework based on the integration of SDN and NFV is proposed to address the function combination issue, including the architecture of Service Deliver Network, the port types representing traffic directions and the explanation of terms. Second, we formulate the issue of load balance of function combination as the model minimizing the standard deviations of all servers' loads and satisfying the demand of performance and limit of resource. The least busy placement algorithm is introduced to approach optimal solution of the problem. Finally, experimental results demonstrate that the proposed method can combine functions in an efficient and scalable way and ensure the load balance of the network.

关键词： software-defined networking network functions virtualization load balance least busy placement algorithm contribution degree