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    COVER PAPER
  • COVER PAPER
    Min Lei, Yixian Yang, Xinxin Niu, Yu Yang, Jie Hao
    2017, 14(7): 1-10.
    Abstract ( )   Knowledge map   Save
    Cyber security lacks comprehensive theoretical guidance. General security theory, as a set of basic security theory concepts, is intended to guide cyber security and all the other security work. The general theory of security aims to unify the main branches of cyber security and establish a unified basic theory. This paper proposal an overview on the general theory of security, which is devoted to constructing a comprehensive model of network security. The hierarchical structure of the meridian-collateral tree is described. Shannon information theory is employed to build a cyberspace security model. Some central concepts of security, i.e., the attack and defense, are discussed and several general theorems on security are presented.
  • COMMUNICATION THEORIES & SYSTEMS
  • COMMUNICATION THEORIES & SYSTEMS
    Fei Wang, Zesong Fei, Jing Wang
    2017, 14(7): 11-24.
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    Hypertext transfer protocol (HTTP) adaptive streaming (HAS) plays a key role in mobile video transmission. Considering the multi-segment and multi-rate features of HAS, this paper proposes a buffer-driven resource management (BDRM) method to enhance HAS quality of experience (QoE) in mobile network. Different from the traditional methods only focusing on base station side without considering the buffer, the proposed method takes both station and client sides into account and end user’s buffer plays as the drive of whole schedule process. The proposed HAS QoE influencing factors are composed of initial delay, rebuffering and quality level. The BDRM method decomposes the HAS QoE maximization problem into client and base station sides separately to solve it in multi-cell and multi-user video playing scene in mobile network. In client side, the decision is made based on buffer probe and rate request algorithm by each user separately. It guarantees the less rebuffering events and decides which HAS segment rate to fetch. While, in the base station side, the schedule of wireless resource is made to maximize the quality level of all access clients and decides the final rate pulled from HAS server. The drive of buffer and twice rate request schemes make BDRM take full advantage of HAS’s multi-segment and multi-rate features. As to the simulation results, compared with proportional fair (PF), Max C/I and traditional HAS schedule (THS) methods, the proposed BDRM method decreases rebuffering percent to 1.96% from 11.1% with PF and from 7.01% with THS and increases the mean MOS of all users to 3.94 from 3.42 with PF method and from 2.15 with Max C/I method. It also guarantees a high fairness with 0.98 from the view of objective and subjective assessment metrics.
  • COMMUNICATION THEORIES & SYSTEMS
    Guanglin Zhang, Jian Liu, Jiajie Ren
    2017, 14(7): 25-33.
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    In this paper, we investigate the upper bound of multicast capacity for content-centric wireless ad hoc networks with content-centric hierarchical routing strategy. We consider two content-centric hierarchical routing strategies, namely, the homogeneous hierarchical routing strategy where each content is requested and cached with equal probability, and the heterogenous hierarchical routing strategy where each content is cached with different probabilities and the requested contents follow a Zipf content popularity distribution. For the two proposed hierarchical routing strategies, we establish the upper bounds on multicast capacity of content-centric wireless ad hoc networks, respectively. We then discuss how the system parameters, such as the number of nodes n, the number of users p, the cache size C, the probability of cache and the content popularity distribution impact on the muilticast capacity scalings.
  • COMMUNICATION THEORIES & SYSTEMS
    Qinglin Zhao, Fangxin Xu, Shangguang Wang
    2017, 14(7): 34-43.
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    In CSMA/CN, whenever inferring that a receiving frame gets corrupted, the receiver sends back its signature as a collision notification (CN) to the sender. Upon detecting an arrival of the CN, the sender will abort the ongoing transmission immediately. However, in low signal-to-interference-plus -noise ratio (SINR), the false alarm of the CN occurs frequently, which might force a sender not to transmit any frame at all. To overcome this drawback, this paper proposes CSMA/CN+ to enhance the performance of CSMA/CN. In CSMA/CN+, we introduce an additional signature. The receiver, adapting to channel conditions and self-signal suppression capability, prudently determines whether to send back zero, one, or two signatures to the sender. In this way, we can reduce or exclude false alarms and therefore improve the system performance. In this paper, we first present the design of CSMA/CN+. We then apply the design in a wireless LAN, and theoretically analyze the detection performance of the notification and the system throughput. Extensive simulations verify that CSMA/CN+ can remarkably improve the system throughput of CSMA/CN and our analysis is very accurate.
  • COMMUNICATION THEORIES & SYSTEMS
    Shuai Zhao, Le Yu
    2017, 14(7): 44-56.
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    Mobile target tracking is a necessary function of some emerging application domains, such as virtual reality, smart home and intelligent healthcare. However, existing portable devices for target tracking are resource intensive and high-cost. Camera tracking is an effective location tracking way for those emerging applications which can reuse the existing ubiquitous video monitoring system. This paper proposes a dynamic community-based camera collaboration (D3C) framework for target location and tracking. The contributions of D3C mainly include that (1) nonlinear perspective projection model is selected as the camera sensing model and sequential Monte Carlo is employed to predict the target location; (2) a dynamic collaboration scheme is proposed, it is based on the local community-detection theory deriving from social network analysis. The performance of proposed approach is validated by both synthetic datasets and real-world application. The experiment results show that D3C meets the versatility, real-time and fault tolerance requirements of target tracking applications.
  • COMMUNICATION THEORIES & SYSTEMS
    Xin Su, Jie Zeng, Yuan Chen, Changpeng Gu, Liping Rong
    2017, 14(7): 57-66.
    Abstract ( )   Knowledge map   Save
    Present mobile communication system suffers from the exponentially increased mobile traffic and research on the fifth generation (5G) mobile network architectures is ongoing to solve this problem. We investigate the feasibility of the proposals used for the network architecture evolution from 4G to 5G and first propose a compatible network architecture, which decouples the management plane, the control plane and the user plane based on NO Stack framework proposed in our previous study. We mainly design detail procedures including UE attachment, service request and dedicated bearer activation/deactivation for our proposal network architecture. Finally, we establish a clear analytical mode of the application and system states to evaluate the signaling loads of new architecture. Simulation results show that our proposal network architecture with elaborated signaling procedures has much impact on the total signaling loads of system and could obviously decrease the signaling overhead compared with LTE.
  • COMMUNICATION THEORIES & SYSTEMS
    Shuangxi Hong, Chuanchang Liu, Bo Cheng, Bingfei Ren, Junliang Chen
    2017, 14(7): 67-77.
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    With the popularity of smartphones and the rapid development of mobile internet, smartphone becomes an important tool that store sensitive data of owner. Encryption naturally becomes a necessary means of protection. In certain situations, this is inadequate, as user may be coerced to hand over decryption keys or passwords of sensitive APP (AliPay) on mobile device. Therefore, only encryption cannot protect sensitive APP and privacy data stored on user’s smartphone. To address these obstacles, we design a protection system called MobiGemini. It enables automatic uninstalling service that can immediately uninstall multiple APP at same time, and also enabling plausibly deniable encryption (PDE) on mobile devices by hiding encrypted volume within random data in free space of cache partition. We improve the key store way of previous PDE schemes on mobile device. The evaluation results show that the scheme introduces a few overhead compared with original android system enabling full disk encryption.
  • NETWORKS & SECURITY
  • NETWORKS & SECURITY
    Lejun Zhang, Hongjie Li, Chunhui Zhao, Xiaoying Lei
    2017, 14(7): 78-92.
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    In this paper, we discuss building an information dissemination model based on individual behavior. We analyze the individual behavior related to information dissemination and the factors that affect the sharing behavior of individuals, and we define and quantify these factors. We consider these factors as characteristic attributes and use a Bayesian classifier to classify individuals. Considering the forwarding delay characteristics of information dissemination, we present a random time generation method that simulates the delay of information dissemination. Given time and other constraints, a user might not look at all the information that his/her friends published. Therefore, this paper proposes an algorithm to predict information visibility, i.e., it estimates the probability that an individual will see the information. Based on the classification of individual behavior and combined with our random time generation and information visibility prediction method, we propose an information dissemination model based on individual behavior. The model can be used to predict the scale and speed of information propagation. We use data sets from Sina Weibo to validate and analyze the prediction methods of the individual behavior and information dissemination model based on individual behavior. A previously proposed information dissemination model provides the foundation for a subsequent study on the evolution of the network and social network analysis. Predicting the scale and speed of information dissemination can also be used for public opinion monitoring.
  • NETWORKS & SECURITY
    Xiaofeng Feng, Xinbo Gao, Ru Zong
    2017, 14(7): 93-107.
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    In cognitive radio networks (CRNs), through recruiting secondary user (SU) as friendly jammer, the secrecy rate obtained by primary user (PU) can be improved. Previous work only considered a simple scenario with a single PU in their frameworks. In this paper, we will consider a more complicated scenario with multiple PUs and try to investigate the cooperative jamming between multiple PUs and a single SU. When there are multiple PUs in CRN, in order to obtain more spectrum for data transmission, SU will cooperate with multiple PUs at the same time. Considering that both PU and SU are rational and selfish individuals, the interaction between PUs and SU is formulated as a multi-leaders and single-follower Stackelberg game, wherein PU is the leader and SU is the follower. And the Stackelberg Equilibrium (SE) is considered as the final decisions accepted by all PUs and SU. Furthermore, we also prove that when a specific condition is satisfied, the existence of SE can be guaranteed. And a Gauss-Jacobi iterative algorithm is proposed to compute a SE. Finally, simulation results are given to verify the performance and demonstrate that both of the PUs’ secrecy rate and the SU’s transmission rate can be improved through cooperation.
  • NETWORKS & SECURITY
    Ao Zhou, Qibo Sun, Jinglin Li
    2017, 14(7): 108-117.
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    Cloud computing is becoming an important solution for providing scalable computing resources via Internet. Because there are tens of thousands of nodes in data center, the probability of server failures is nontrivial. Therefore, it is a critical challenge to guarantee the service reliability. Fault-tolerance strategies, such as checkpoint, are commonly employed. Because of the failure of the edge switches, the checkpoint image may become inaccessible. Therefore, current checkpoint-based fault tolerance method cannot achieve the best effect. In this paper, we propose an optimal checkpoint method with edge switch failure-aware. The edge switch failure-aware checkpoint method includes two algorithms. The first algorithm employs the data center topology and communication characteristic for checkpoint image storage server selection. The second algorithm employs the checkpoint image storage characteristic as well as the data center topology to select the recovery server. Simulation experiments are performed to demonstrate the effectiveness of the proposed method.
  • NETWORKS & SECURITY
    Jiansheng Yao, Chunguang Ma, Haitao Yu, Yanling Liu, Qi Yuan
    2017, 14(7): 118-126.
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    In opportunistic networks, most existing buffer management policies including scheduling and passive dropping policies are mainly for routing protocols. In this paper, we proposed a Utility-based Buffer Management strategy (UBM) for data dissemination in opportunistic networks. In UBM, we first design a method of computing the utility values of caching messages according to the interest of nodes and the delivery probability of messages, and then propose an overall buffer management policy based on the utility. UBM driven by receivers completely implements not only caching policies, passive and proactive dropping policies, but also scheduling policies of senders. Simulation results show that, compared with some classical dropping strategies, UBM can obtain higher delivery ratio and lower delay latency by using smaller network cost.
  • NETWORKS & SECURITY
    Xiong Luo, Jing Deng, Ji Liu, Weiping Wang, Xiaojuan Ban, Jenq-Haur Wang
    2017, 14(7): 127-136.
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    Quantized kernel least mean square (QKLMS) algorithm is an effective nonlinear adaptive online learning algorithm with good performance in constraining the growth of network size through the use of quantization for input space. It can serve as a powerful tool to perform complex computing for network service and application. With the purpose of compressing the input to further improve learning performance, this article proposes a novel QKLMS with entropy-guided learning, called EQ-KLMS. Under the consecutive square entropy learning framework, the basic idea of entropy-guided learning technique is to measure the uncertainty of the input vectors used for QKLMS, and delete those data with larger uncertainty, which are insignificant or easy to cause learning errors. Then, the dataset is compressed. Consequently, by using square entropy, the learning performance of proposed EQ-KLMS is improved with high precision and low computational cost. The proposed EQ-KLMS is validated using a weather-related dataset, and the results demonstrate the desirable performance of our scheme.
  • NETWORKS & SECURITY
    Kai Kang, Zhenghang Zhu, Dehua Liu, Wuxiong Zhang, Hua Qian
    2017, 14(7): 137-151.
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    Wireless local area network (WLAN) is an indivisible part of the next generation wireless system. In this paper, an open Wi-Fi platform is designed and developed with special consideration of real-time signal processing. Such system can help accelerate research and development of future wireless network, especially in the case of cellular/Wi-Fi co-existing networks. This platform is based on the Intel general-purpose processor and the universal software radio peripheral (USRP) radio front end. The design including the physical layer implementations is purely software and is optimized for real-time signal processing on the general purpose processor. In the lab experiment, this platform supports baseband rate up to 700 Mbps with 2 transmitters in 80 MHz bandwidth. A cellular-Wi-Fi signaling interface between the Wi-Fi access point (AP) and the 5G core network is also developed and validated as an example for wireless resource allocation.
  • SIGNAL PROCESSING FOR COMMUNICATIONS
  • SIGNAL PROCESSING FOR COMMUNICATIONS
    Zhonghua Liang, Junshan Zang, Xiaojun Yang, Xiaodai Dong, Huansheng Song
    2017, 14(7): 152-162.
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    In order to guarantee reliable data transmission, powerful channel coding techniques are usually required in noncoherent ultra-wideband (UWB) communication systems. Accordingly, several forward error correction (FEC) codes, such as Reed-Solomon and convolutional codes have been used in noncoherent UWB systems to improve the bit error rate (BER) performance. In this paper, low-density parity-check (LDPC) codes are further studied as more powerful FEC candidates for noncoherent UWB systems. Two LDPC codes and the corresponding decoding procedures are presented for noncoherent UWB systems. Moreover, performance comparison between the LDPC codes and other FEC codes are provided for three major noncoherent UWB communication systems, namely, noncoherent pulse position modulation (NC-PPM), transmitted reference (TR) and transmitted reference pulse cluster (TRPC). Both theoretical analysis and simulation results show that the two investigated LDPC codes outperform other existing FEC codes with limited penalty in terms of complexity and therefore they are promising FEC candidates for noncoherent UWB systems with low- cost and low-power consumption.
  • SIGNAL PROCESSING FOR COMMUNICATIONS
    Yuan Liu, Weigang Chen*
    2017, 14(7): 163-171.
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    Forward-backward algorithm, used by watermark decoder for correcting non-binary synchronization errors, requires to traverse a very large scale trellis in order to achieve the proper posterior probability, leading to high computational complexity. In order to reduce the number of the states involved in the computation, an adaptive pruning method for the trellis is proposed. In this scheme, we prune the states which have the low forward-backward quantities below a carefully-chosen threshold. Thus, a wandering trellis with much less states is achieved, which contains most of the states with quite high probability. Simulation results reveal that, with the proper scaling factor, significant complexity reduction in the forward-backward algorithm is achieved at the expense of slight performance degradation.
  • SIGNAL PROCESSING FOR COMMUNICATIONS
    Junyi Xi, Shefeng Yan, Lijun Xu, Jing Tian
    2017, 14(7): 172-183.
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    This paper proposes a soft direct-adaptation based bidirectional turbo equalizer for multiple-input multiple-output underwater acoustic communication systems. Soft, rather than hard, direct-adaptation based equalizer combined with the fast self-optimized least mean square algorithm is employed to achieve a faster convergence rate, and the second-order phase-locked loop is embedded into the equalizer to track the time-varying channel. Meanwhile, by utilizing a weighted linear combining scheme, the conventional soft direct-adaptation based equalizer is combined with the time-reversed soft direct-adaptation based equalizer to exploit bidirectional diversity and mitigate error propagation. Both the simulation and experimental results demonstrate that the soft direct-adaptation based bidirectional turbo equalizer outperforms the single-direction soft direct-adaptation based turbo equalizer, and achieves a faster convergence rate than the hard direct-adaptation based bidirectional turbo equalizer.
  • SIGNAL PROCESSING FOR COMMUNICATIONS
    Cheng Wang, Gaofeng Cui, Weidong Wang, Yinghai Zhang
    2017, 14(7): 184-194.
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    Spectral efficiency and energy efficiency are two important performance indicators of satellite systems. The Quasi-Constant Envelope Orthogonal Frequency Division Multiplexing (QCE-OFDM) technique can achieve both high spectral efficiency and low peak-to-average power ratio (PAPR). Therefore, the QCE-OFDM technique is considered as a promising candidate multi-carrier technique for satellite systems. However, the Doppler effect will cause the carrier frequency offset (CFO), and the non-ideal oscillator will cause the carrier phase offset (CPO) in satellite systems. The CFO and CPO will further result in the bit-error-rate (BER) performance degradation. Hence, it is important to estimate and compensate the CFO and CPO. This paper analyzes the effects of both CFO and CPO in QCE-OFDM satellite systems. Furthermore, we propose a joint CFO and CPO estimation method based on the pilot symbols in the frequency domain. In addition, the optimal pilot symbol structure with different pilot overheads is designed according to the minimum Cramer-Rao bound (CRB) criterion. Simulation results show that the estimation accuracy of the proposed method is close to the CRB.
  • SIGNAL PROCESSING FOR COMMUNICATIONS
    Xue Jiang, Baoyu Zheng*, Yuelin Du
    2017, 14(7): 195-203.
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    Interference alignment (IA) is one of the promising measures for the multi-user network to manage interference. The rank constraints rank minimization means that interference spans the lowest dimensional subspace and the useful signal spans all available spatial dimensions. In order to improve the performance of two-way relay network, we can use rank constrained rank minimization (RCRM) to solve the IA problem. This paper proposes left reweighted nuclear norm minimization-γ algorithm and selective coupling reweighted nuclear norm minimization algorithm to implement interference alignment in two-way relay networks. The left reweighted nuclear norm minimization-γ algorithm is based on reweighted nuclear norm minimization algorithm and has a novel γ choosing rule. The selective coupling reweighted nuclear norm minimization algorithm weighting methods choose according to singular value of interference matrixes. Simulation results show that the proposed algorithms considerably improve the sum rate performance and achieve the higher average achievable multiplexing gain in two-way relay interference networks.
  • EMERGING TECHNOLOGIES & APPLICATIONS
  • EMERGING TECHNOLOGIES & APPLICATIONS
    Ying Wang, Yichun Xu, Yuan Zhang, Ping Zhang
    2017, 14(7): 204-216.
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    Natural disaster or large-scale unexpected events easily make the terrestrial network overloaded,paralyzed, or totally destroyed. It is highly demanded to build an emergency network which can be deployed rapidly, offer high data rate and wide coverage. The emergence of aerial platforms especially the low altitude platforms (LAPs) indicates a stable and reliable direction for the development of emergency network. Hybrid satellite-aerial-terrestrial (HSAT) networks have the ability to provide effective services rather than traditional infrastructures during the emergency situation. In this paper, the aerial platforms and the HSAT networks are surveyed and the key technologies are discussed from several aspects. The challenges of the HSAT networks are also outlined finally.