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  • November 2016 Vol. 13 No. 11
      

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  • Hui Zhuang, Jintao Li, Weibiao Geng, Xiaoming Dai
    2016, 13(11): 1-13.
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    The full-duplex (FD) based wireless communication devices, which are capable of concurrently transmitting and receiving signals with a single frequency band, suffer from a severe self-interference (SI) due to the large power difference between the devices’ own transmission and the useful signal comes from the remote transmitters. To enable the practical FD devices to be implementable, the SI power must be sufficiently suppressed to the level of background noise power, making the received signal-to-interference-plus-noise ratio (SINR) satisfy the decoding requirement. In this paper, the design and implementation of the duplexer for facilitating SI cancellation in FD based wireless communications are investigated, with a new type of duplexer (i.e. an improved directional coupler) designed for improving the spatial suppression of the SI power. Furthermore, the practical circuit boards are designed and verified for the proposed prototype, showing that the spatial suppression capability may be up to 36dB (i.e. much higher than that attainable in the commonly designed ferrite circulator) by using the proposed design.
  • Jia You, Zhangdui Zhong, Zhongzhao Dou, Jing Dang, Gongpu Wang
    2016, 13(11): 14-26.
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    In this paper, we introduce one full-duplex (FD) relaying transmission scheme for high speed railway and compare its ergodic capacity and outage performance with half-duplex (HD) relaying scheme. Both decode-and-forward (DF) amplify-and-forward (AF) relay modes are considered. Moreover, the carriage penetration loss (CPL) and the self-interference (SI) cancellation ratio are investigated. We derive the closed-form expressions for the outage probability and ergodic capacity of both HD and FD relay transmission schemes. It is shown that when CPL is larger than a certain level, the FD relay can achieve better performance in terms of capacity and keep the outage probability in a low level. It is also found that three factors: AF or DF modes, CPL and SI cancellation ratio, can have impact on capacity performance, and that CPL is one decisive factor. Our results can provide theoretical supports for development and deployment of future wireless communication systems on high speed railways.
  • Lu Tian, Shuai Wang, Zhiheng Cheng, Xiangyuan Bu
    2016, 13(11): 27-34.
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    In this paper, a general scheme in digital self-interference cancellation at baseband for zero-IF full-duplex transceivers is presented. We model the self-interference signals specifically with only the nonlinear distortion signals falling in receiving band considered. A joint estimation algorithm is proposed for compensating the time delay and frequency offset taking into account the IQ amplitude and phase imbalances from mixers. The memory effect and nonlinear distortion are adaptively estimated by the de-correlated normalized least mean square (DNLMS) algorithm. Numerical simulation results demonstrate that the proposed self-interference cancellation scheme can efficiently compensate the self-interference and outperform the existing traditional solutions.
  • Xiaohui Sun, Dandan Zhang, Xiaoming Dai
    2016, 13(11): 35-48.
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    Cooperative communication is regarded as a promising technique for improving the reliability of wireless communication links and enhancing the radio coverage simultaneously. Unlike the conventional half-duplex (HD) mode relaying techniques, the full-duplex based two-way relaying (FD-TWR) enables data exchanges between two nodes to be completed within a single time-slot, thus resulting in a significant improvement in the spectrum efficiency. In this paper, the channel model of the FD-TWR is first given out, followed by deriving the critical performance metrics, including the received signal-to-interference-plus-noise ratio (SINR), the upper bound of the ergodic capacity and the closed-form solution of the proposed FD-TWR under amplify-and-forward (AF) mode. Furthermore, taking the limit of sum-transmit-power into account, we formulate the objective function of the optimal power allocation of FD-TWR as an extreme-value problem by deriving the optimal transmit power for both the source nodes and the relay node. As long as the self-interference (SI) signal in the FD-TWR nodes can be sufficiently suppressed, the proposed scheme is shown to outperform the conventional HD mode in terms of both the ergodic capacity and the outage probability. In addition, regardless of the practical SI power,the proposed FD-TWR is always capable of achieving its best performance with an aid of the proposed optimal power allocation scheme.
  • Wen Zhao, Chunyan Feng, Fangfang Liu, Caili Guo
    2016, 13(11): 49-59.
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    In MIMO full duplex system, power amplifier (PA) nonlinearity limits the self-interference (SI) cancellation seriously. Most existing methods need to model and estimate the PA nonlinearity in order to reconstruct the SI, however the estimation error caused by the mismatch between the estimated PA model and the actual PA property still impacts the cancellation ability, especially when the transmit power is high. In this paper we propose a polarization oblique projection based self-interference cancellation method which does not need to estimate the PA nonlinearity coefficients. It exploits the polarization state information of the signals which is immune to the PA nonlinearity, and establishes an oblique projection operator to cancel the SI. Numerical results and analysis demonstrate that it can cancel the nonlinear SI effectively. Moreover the signal to interfere plus noise ratio (SINR) and the achievable sum rate do not deteriorate when the transmit power is high. Further, the upper bound of the achievable sum rate can be more than twice that of the half duplex.
  • Bin Zhong, Jiajia Zhang, Qian Zeng, Xiaoming Dai
    2016, 13(11): 60-69.
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    The coverage probability of both the cellular users and the Device-to-Device (D2D) users are analyzed. We assume that the cellular users are able to communication with the Base Station (BS) either by relying on the assistance of Full-Duplex (FD) mode relays or via direct user-to-BS links with high-enough Signal-to-Interference-plus-Noise-Ratio (SINR). Note that the FD-mode devices are capable of simultaneously operating in two modes, i.e. the D2D mode and the cooperative relay mode, with the sum power consumption at these devices kept constant. The closed-form expressions for coverage probability of both tier users are derived. After that, numerical analyses are provided, showing that the coverage probability of the both the cellular and the D2D users can be substantially influenced by a variety of parameters, including the power allocation factor of the relays, the density of users, and the self-interference imposed on the FD mode relays, etc. Furthermore, in the D2D enabled networks, it is shown that the FD relay aided transmission is beneficial to enhancing the coverage probability of the cellular users if the target SINR is lower than 5 dB.
  • Juan Wang, Yuan Shi, Guojun Peng, Huanguo Zhang, Bo Zhao, Fei Yan, Fajiang Yu, Liqiang Zhang
    2016, 13(11): 70-90.
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    Trusted computing, which can effectively increase the credibility of information system, has made great achievements and is in continuous development. For country who is going to strengthen network construction like China, it is an important fundamental supporting technology worth researching. China is in the international forefront in the field of trusted computing. This paper gives comprehensive introductions to the new development and application of key technologies in trusted computing, such as various trusted platform modules (TPM、TCM、TPCM), TCG Software Stack (TSS), trusted cloud server and Trusted Execution Environment (TEE). We illustrate the progressing and application extension of these technologies and also point out some key problems worth studying in the future.
  • Yonggan Li, Xueguang Zhou, Yan Sun, Huanguo Zhang
    2016, 13(11): 91-105.
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    Information content security is a branch of cyberspace security. How to effectively manage and use Weibo comment information has become a research focus in the field of information content security. Three main tasks involved are emotion sentence identification and classification, emotion tendency classification, and emotion expression extraction. Combining with the latent Dirichlet allocation (LDA) model, a Gibbs sampling implementation for inference of our algorithm is presented, and can be used to categorize emotion tendency automatically with the computer. In accordance with the lower ratio of recall for emotion expression extraction in Weibo, use dependency parsing, divided into two categories with subject and object, summarized six kinds of dependency models from evaluating objects and emotion words, and proposed that a merge algorithm for evaluating objects can be accurately evaluated by participating in a public bakeoff and in the shared tasks among the best methods in the sub-task of emotion expression extraction, indicating the value of our method as not only innovative but practical.
  • Chunguang Ma, Lei Zhang, Songtao Yang, Xiaodong Zheng, Pinhui Ke
    2016, 13(11): 106-118.
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    In cyberspace security, the privacy in location-based services (LBSs) becomes more critical. In previous solutions, a trusted third party (TTP) was usually employed to provide disturbance or obfuscation, but it may become the single point of failure or service bottleneck. In order to cope with this drawback, we focus on another important class, establishing anonymous group through short-range communication to achieve k-anonymity with collaborative users. Along with the analysis of existing algorithms, we found users in the group must share the same maximum anonymity degree, and they could not ease the process of preservation in a lower one. To cope with this problem, we proposed a random-QBE algorithm to put up with personalized anonymity in user collaboration algorithms, and this algorithm could preserve both query privacy and location privacy. Then we studied the attacks from passive and active adversaries and used entropy to measure user’s privacy level. Finally, experimental evaluations further verify its effectiveness and efficiency.
  • Liqiang Zhang, Fei Yan, Bo Zhao, Shouhuai Xu
    2016, 13(11): 119-128.
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    Despite the tremendous effort made by industry and academia, we are still searching for metrics that can characterize Cyberspace and system security risks. In this paper, we study the class of security risks that are inherent to the dependence structure in software with vulnerabilities and exhibit a "cascading" effect. We present a measurement framework for evaluating these metrics, and report a preliminary case study on evaluating the dependence-induced security risks in the Apache HTTP Server. The experiment results show that our framework can not only clearly analyze the root cause of the security risks but also quantitatively evaluate the attack consequence of the risks.
  • Jinan Shen, Deqing Zou, Hai Jin, Kai Yang, Bin Yuan, Weiming Li
    2016, 13(11): 129-142.
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    In traditional framework, mandatory access control (MAC) system and malicious software are run in kernel mode. Malicious software can stop MAC systems to be started and make it do invalid. This problem cannot be solved under the traditional framework if the operating system (OS) is comprised since malwares are running in ring0 level. In this paper, we propose a novel way to use hypervisors to protect kernel integrity and the access control system in commodity operating systems. We separate the access control system into three parts: policy management (PM), security server (SS) and policy enforcement (PE). Policy management and the security server reside in the security domain to protect them against malware and the isolation feather of the hypervisor can protect them from attacks. We add an access vector cache (AVC) between SS and PE in the guest OS, in order to speed up communication between the guest OS and the security domain. The policy enforcementmodule is retained in the guest OS for performance. The security of AVC and PE can be ensured by using a memory protection mechanism. The goal of protecting the OS kernel is to ensure the security of the execution path. We implement the system by a modified Xen hypervisor. The result shows that we can secure the security ofthe access control system in the guest OS with no overhead compared with modules in the latter. Our system offers a centralized security policy for virtual domains in virtual machine environments.
  • Donghai Tian, Xiaoqi Jia, Junhua Chen, Changzhen Hu, Jingfeng Xue
    2016, 13(11): 143-152.
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    Heap overflow attack is one of the major memory corruption attacks that have become prevalent for decades. To defeat this attack, many protection methods are proposed in recent years. However, most of these existing methods focus on user-level heap overflow detection. Only a few methods are proposed for kernel heap protection. Moreover, all these kernel protection methods need modifying the existing OS kernel so that they may not be adopted in practice. To address this problem, we propose a lightweight virtualization-based solution that can protect the kernel heap buffers allocated for the target kernel modules. The key idea of our approach is to combine the static binary analysis and virtualization technology to trap a memory allocation operation of the target kernel module, and then add one secure canary word to the end of the allocated buffer. After that, a monitor process is launched to check the integrity of the canaries. The evaluations show that our system can detect kernel heap overflow attacks effectively with minimal performance cost.
  • Jinfu Chen, Lili Zhu, Zhibin Xie, Michael Omari, Hilary Ackah-Arthur1, Saihua Cai, Rubing Huang
    2016, 13(11): 153-169.
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    In the execution of method invocation sequences to test component security, abnormal or normal information is generated and recorded in a monitor log. By searching abnormal information from monitor log, the exceptions that the component has can be determined. To facilitate the searching process, string searching methods could be employed. However, current approaches are not effective enough to search long pattern string. In order to mine the specific information with less number of matches, we proposed an improved Sunday string searching algorithm in this paper. Unlike Sunday algorithm which does not make use of the already matched characters, the proposed approach presents two ideas — utilizing and recycling these characters. We take advantage of all matched characters in main string, if they are still in the matchable interval compared with pattern string, to increase the distance that pattern string moves backwards. Experimental analysis shows that, compared to Sunday algorithm, our method could greatly reduce the matching times, if the scale of character set constituting both main string and pattern string is small, or if the length of pattern string is long. Also, the proposed approach can improve the search effectiveness for abnormal information in component security testing.
  • Lizhao Liu, Wentu Gao, Jian Liu, Huayi Yin, Huarong Xu, Shunzhi Zhu
    2016, 13(11): 170-179.
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    An image trust root is a special type of soft trust root for trusted computing. However, image trust root generation is difficult, as it needs a corresponding stable logic feature generation model and algorithm for dynamical and sustained authentication. This paper proposes a basic function of constructing new scale-spaces with deep detecting ability and high stability for image features aimed at image root generation. According to the heat distribution and spreading principle of various kinds of infinitesimal heat sources in the space medium, a multi-embed nonlinear diffusion equation that corresponds to the multi-embed nonlinear scale-space is proposed, a HARRIS-HESSIAN scale-space evaluation operator that aims at the structure acceleration characteristics of a local region and can make use of image pixels’ relative spreading movement principle was constructed, then a single-parameter global symmetric proportion (SPGSP) operator was also constructed. An authentication test with 3000 to 5000 cloud entities shows the new scale-space can work well and is stable, when the whole cloud has 5%-50% behavior with un-trusted entities. Consequently, it can be used as the corresponding stable logic feature generation model and algorithm for all kinds of images, and logic relationships among image features for trust roots.
  • Lin Ding, Chenhui Jin, Jie Guan, Shaowu Zhang, Junzhi Li, Hong Wang, Wei Zhao
    2016, 13(11): 180-188.
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    The Grain v1 stream cipher is one of the seven finalists in the final eSTREAM portfolio. Though many attacks have been published, no recovery attack better than exhaustive key search on full Grain v1 in the single key setting has been found yet. In this paper, new state recovery attacks on Grain v1 utilizing the weak normality order of the employed keystream output function in the cipher are proposed. These attacks have remarkable advantages in the offline time, online time and memory complexities, which are all better than exhaustive key search. The success probability of each new attack is 0.632. The proposed attack primarily depends on the order of weak normality of the employed keystream output function. This shows that the weak normality order should be carefully considered when designing the keystream output functions of Grain-like stream ciphers.
  • Fei Xu, Yaojun Qiao, Ji Zhou, Huiping Tian
    2016, 13(11): 189-196.
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    We proposed a hybrid transmission system consist of 1Tbit/s Nyquist WDM channels, 100Gbit/s PDM-QPSK WDM channels and 10Gbit/s NRZ WDM channels to study whether Terabit Nyquist WDM signal could transmit in the existing hybrid systems with DCM (dispersion compensation module). The simulation results demonstrated the influence of all these three kinds of signals. The 1Tbit/s Nyquist WDM channels introduced 1.5dB Q penalty to the 100Gbit/s PDM-QPSK signals and their influence on the 10Gbit/s NRZ signals was extremely slight. In the hybrid optical system, 1Tbit/s Nyquist channel has 5dB Q penalty due to the inline DCM and 2.5dB Q penalty due to the channel interference from existing channels. Therefore, the total Q penalty is 7.5dB caused by strong nonlinear effects at the launch power of 0dBm. The results have the guiding significance for the design of future backbone system and also support the feasibility of future dynamic optical system.
  • Jianbo Du, Liqiang Zhao, Jie Feng, Jie Xin, Yong Wang
    2016, 13(11): 197-204.
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    In order to maximize system energy efficiency (EE) under user quality of service (QoS) restraints in Long Term Evolution-Advanced (LTE-A) networks, a constrained joint resource optimization allocation scheme is presented, which is NP-hard. Hence, we divide it into three sub-problems to reduce computation complexity, i.e., the resource block (RB) allocation, the power distribution, and the modulation and coding scheme (MCS) assignment for user codewords. Then an enhanced heuristic approach GAPSO is proposed and is adopted in the RB and power allocation respectively to reduce computational complexity further on. Moreover, a novel MCS allocation scheme is put forward, which could make a good balance between the system reliability and availability under different channel conditions. Simulation results show that the proposed GAPSO could achieve better performance in convergence speed and global optimum searching, and that the joint resource allocation scheme could improve energy efficiency effectively under user QoS requirements.
  • Hongning Li, Qingqi Pei, Leilei Xu
    2016, 13(11): 205-213.
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    As a constraint for smart devices, energy consumption has attract people’s attention for a long time period. How to get higher resource utilization with less energy consumption is a challenge for cognitive radio networks. Secondary users have to participate in spectrum sensing at the cost of energy and access idle spectrum without interfering primary users. However, not all participating secondary users can access idle spectrum. How to ensure the participation users access spectrum efficiently with a larger probability is an urgent problem to be solved. We propose an Energy Efficiency-based Decision Making (EEDM) for cognitive radio networks, which fully considers residual energy and probability of obtaining spectrum resources. Simulation and analysis show that the proposed scheme can maximize proportion of allocated users under the premise of ensuring the accuracy of spectrum sensing, then balance users’ energy consumption and access efficiency, so as to effectively improve the utilization of spectrum resources.
  • Xinyu Wang, Min Jia, Qing Guo, Xuemai Gu, Jian Yang
    2016, 13(11): 214-225.
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    The majority of existing papers about spectrum sensing have the assumption that secondary users (SUs) are stationary. However, mobility is an essential feature of mobile communications networks. In this paper, the detection performance of spectrum sensing by mobile SUs was analyzed. Three performance metrics, i.e., detection probability, miss detection probability and false alarm probability, were thoroughly investigated. In our analysis, a critical variable was the real-time received primary user signal power by a mobile SU. Its probability distribution and mathematical expectation were analytically derived. Moreover, the three performance metrics in single-node spectrum sensing and multi-node collaborative spectrum sensing systems were also derived. Extensive simulations were performed. The results are consistent with the theoretical analysis. And it is concluded that SU mobility has a significant impact on the detection probability and the miss detection probability, but not on the false alarm probability.
  • Mingjin Gao, HeChen, Yonghui Li, Yiqing Zhou, Jinglin Shi
    2016, 13(11): 226-233.
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    In centralized cellular network architecture, the concept of virtualized Base Station (VBS) becomes attracting since it enables all base stations (BSs) to share computing resources in a dynamic manner. This can significantly improve the utilization efficiency of computing resources. In this paper, we study the computing resource allocation strategy for one VBS by considering the non-negligible effect of delay introduced by switches. Specifically, we formulate the VBS’s sum computing rate maximization as a set optimization problem. To address this problem, we firstly propose a computing resource schedule algorithm, namely, weight before one-step-greedy (WB-OSG), which has linear computation complexity and considerable performance. Then, OSG retreat (OSG-R) algorithm is developed to further improve the system performance at the expense of computational complexity. Simulation results under practical setting are provided to validate the proposed two algorithms.
  • Xiangbin Yu, Ying Wang, Qiuming Zhu, Tao Dong, Junya Chu
    2016, 13(11): 234-243.
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    The energy efficiency (EE) of distributed antenna system with quality of service (QoS) requirement is investigated over composite Rayleigh fading channel, where the shadow fading, path loss and Rayleigh fading are all considered. Our aim is to maximize the EE which is defined as the ratio of the transmission rate to the total consumed power subject to the maximum transmit power of each remote antenna constraint and QoS (target BER) requirement. According to the definition of EE and using the upper bound of average EE, the optimized objective function is provided. Based on this, utilizing Karush-Kuhn-Tucker conditions and numerical calculation, a suboptimal energy efficient power allocation (PA) scheme is developed, and the closed-form expression of PA coefficients is derived. The scheme may obtain the EE performance close to the existing optimal scheme. Moreover, it has relatively lower complexity than the existing scheme because only the statistic channel information and less iteration are required. Simulation results show the presented scheme is valid and can meet the target BER requirement, and the EE can be increased as target BER requirement decreases.
  • Wenbin Liu, Yongjian Yang, Fan Wang, En Wang
    2016, 13(11): 244-259.
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    Recently, ultrasonic waves had been introduced as the transmission medium in Body Area Networks (BANs) to reduce the incalculable damage caused by radio waves. However, the communications based on ultrasonic waves suffer from poor propagation of signals in air and consume too much energy. To address these limitations, firstly, we make the theoretical analysis to ensure ultrasonic waves could be used in BANs (UBANs). Then, we propose an error control strategy in UBANs to dynamically adjust the error control scheme and the Max-Retries based on the current channel state, which is called UECS. The UECS is based on IEEE 802.15.6 standards and considering the characteristics of ultrasonic waves in BANs. Simulation results show that UECS achieves better performance in terms of packet delivery ratio and energy consumption compared with the traditional strategies.
  • Lili Tong, Xiaoge Hou, Xiaowen Li
    2016, 13(11): 260-268.
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    The rapid development of industry application products has greatly influenced society. It has become essential for some telecommunication companies to focus on customer satisfaction with industrial products used by the government and enterprise customers. Following the review of a previous study of customer satisfaction and with the help of experiential level theory, this article attempts to establish a Satisfaction Factors Model for researching customer satisfaction with industry applications. We chose a product named “Mobile Monitor” and investigated the emotional satisfaction of 127 users and company leaders from different walks of life, and showed that 7 of the product’s features affected the customers’ overall emotional satisfaction. Lastly, this paper points out management implications of this application based on quantitative results. It presents a preliminary exploration program for customer satisfaction research in this specific field. The empirical research on a specific product based on experimental level theory may serve as a reference for other companies that desire to carry out similar surveys in future.
  • Pengcheng Zhang, Yingtao Sun, Hareton Leung, Meijun Xu, Wenrui Li
    2016, 13(11): 269-280.
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    As an important factor in evaluating service, QoS (Quality of Service) has drawn more and more concerns with the rapid increasing of Web services. However, due to the great volatility of services in Mobile Internet environments, such as internet of vehicles, Web services often do not work as announced and thus cause unacceptable problems. QoS prediction can avoid failure before it takes place, which is considered a more effective way to assure quality. However, Current QoS prediction approaches neither consider the highly dynamic of Web services, nor maintain good prediction performance all the time. Consequently we propose a novel Bayesian combinational model to predict QoS by continuously adjusting credit values of the basic models so as to keep good prediction accuracy. QoS attributes such as response time, throughput and reliability are used to validate the proposed model. Experimental results show that the model can provide stable prediction results in Mobile Internet environments.