Current Issue

• • 2017, Vol. 40 No. 2 Published date:28 April 2017 Last issue Next issue

  Review

  • Mobile Edge Computing for 5G Requirements
  • TIAN Hui, FAN Shao-shuai, LÜ Xin-chen, ZHAO Peng-tao, HE Shuo
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 1-10. DOI:10.13190/j.jbupt.2017.02.001
  • Abstract ( 656 )     HTML     　　
  • Mobile edge computing is a key technique to help push the envelope of performance to provide much lower latency, ultra-high energy efficiency, ultra-high reliability and much higher connectivity density in the fifth generation of mobile technology (5G). Fine-granularity based task offloading algorithms, task offloading and prediction algorithms with high reliability and joint resource management policy were introduced to report the progress of mobile edge computing toward the 5G business requirement. A number of challenges and potential research directions in mobile edge computing were also given.
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  Papers

  • Jointly Optimize CRE and eICIC in Heterogeneous Cellular Networks with Non-Uniform User Distribution
  • TAN Zhi-yuan, CHEN Lei, LI Xi, JI Hong
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 11-15. DOI:10.13190/j.jbupt.2017.02.002
  • Abstract ( 300 )     HTML     　　
  • As the effective methods to solve the load balance and interference control problem in heterogeneous cellular networks (HCN), cell range expansion (CRE) and enhanced inter-cell interference (eICIC) attract the attention of many researchers. However, most of the current works are under the assumption of uniform user distribution for simplicity, which is not applicable for the non-uniform user distribution scene. We intend to jointly optimize CRE and eICIC in HCN with non-uniform user distribution. Due to the complexity of the optimization problem, Stackelberg Game is used to model the optimization process of CRE and eICIC where macro base station (MBS) decides the eICIC strategy as leader and small cell base stations decide the respective CRE scheme as followers. Moreover, a solution algorithm is proposed to achieve the Stackelberg equilibrium (SE). The simulation results show the convergence of our proposed algorithm of SE and the effectiveness of our proposed solution.
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  • A Part-of-Speech Tagging Algorithm for Essay Written by Chinese English Learner
  • TAN Yong-mei, YANG Lin, HU Dan
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 16-20. DOI:10.13190/j.jbupt.2017.02.003
  • Abstract ( 287 )     HTML     　　
  • A tagging algorithm about two layers part-of-speech base on word embedding was proposed. Only a few artificial features are needed in this algorithm, most features are replaced by word embedding and tagging vector that is got in the first layer. In addition, the tag set is divided into two categories, which are the tag sets of different layers. The ones which are easily to be tagged are tagged firstly in the first layer.Those tags which are hardly to be tagged as noun and verb are tagged in the second layer. Using this algorithm, the accuracy of part-of-speech tagging of essays written by Chinese English learner is improved from 95.23% to 95.63%, which outperforms the state-of-art word results of part-of-speech tagging of essays written by Chinese English learner based on vector based on word embedding.
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  • Polarization Division Multiplexing System with Direct Decision for Short Reach Optical Communications
  • ZHOU Xian, HUO Jia-hao, ZHONG Kang-ping, LONG Ke-ping, LÜ Chao
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 21-28. DOI:10.13190/j.jbupt.2017.02.004
  • Abstract ( 408 )     HTML     　　
  • The communications and processing of big data brings great pressure to the short reach optical systems because of its ever-increasing requirement on transmission rate. However, the upgrade of transmission systems faced many factors in cost, speed, and distance. Polarization division multiplexing combined with direct detection (PDM-DD) is a promising way to significantly improve the transmission rate of short reach systems. Three popular PDM-DD approaches were analyzed in Stokes vector space theoretically, in which, their performance are investigated by simulation with uniform model parameters.
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  • Load-Balanced Clustering Scheme for WIA-PA Industrial Wireless Networks
  • WANG Heng, XIA Shu-yang, WANG Ping
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 29-35,42. DOI:10.13190/j.jbupt.2017.02.005
  • Abstract ( 457 )     HTML     　　
  • For the imbalance issue of data transmission among cluster-heads in wireless networks for industrial automation-process automation (WIA-PA), a new load-balanced clustering scheme is presented. A periodic data throughput model is firstly established based on WIA-PA network characteristics. Then a cluster-head selection algorithm and an improved joining method for field devices is proposed. The field devices prefer to select the router with the minimum throughput as their cluster-head,so as to adjust network topology adaptively according to the data traffic. The tests show that the proposed scheme can effectively balance the data traffic and energy consumption among cluster-heads,and extend the lifetime of WIA-PA networks.
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  • The Elliptical Scattering Channel Modeling Based on Von Mises Distribution
  • ZHOU Jie, YUAN Mei, TANG Deng-hong
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 36-42. DOI:10.13190/j.jbupt.2017.02.006
  • Abstract ( 457 )     HTML     　　
  • To study the transmission characteristics of the channel under isotropic and non-isotropic scattering environments, a geometric elliptical scattering model was established. Both the transmitter and receiver are adapted uniform linear array to research multiple-input multiple-output performance. First, assume that the angle of arrival (AOA) obey Von Mises density distribution. In the quantitative analysis of the relationship between AOA and angel of departure, the time auto correlation function, the spatial correlation function of the reference model are analyzed, so as the channel capacity. In addition, a parameter calculation method based exact doppler spread was proposed, and a simulation model was obtained based on a reference model. The statistics of the proposed model illustrates the influence of the characteristic of the channel model under the Von Mises distribution. Analysis and simulation show that the channel simulator and the reference model have almost the same time correlation function, and this model also extends the research of spatial statistical channel model.
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  • Dynamic Spectrum Allocation Scheme Based on Game Theory in Cognitive D2D Communication
  • XIE Xian-zhong, LI Chuan-wen, YANG He-lin
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 43-48. DOI:10.13190/j.jbupt.2017.02.007
  • Abstract ( 384 )     HTML     　　
  • The author develops a new non-cooperative game dynamic spectrum allocation scheme. This scheme considers multiple cellular service providers and D2D service group which have the cognitive ability, and uses the Bertrand game theory to solve the problem of user spectrum allocation. The utility function of D2D service group and cellular service providers are improved respectively. This article also puts forward optimal pricing of cellular service providers and dynamic price adjustment strategy of D2D service group. Furthermore, the existence of a Nash equilibrium state and the convergence of the algorithm are proved. By simulation and experiment, the impact of different numbers of cellular users and different learning factors on the performance of the proposed scheme is analyzed. Compared with existing ones, this scheme improves both the spectrum utilization and system fairness.
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  • Query Processing over Constraint Event Stream with Uncertain Timestamps
  • LI Fang-fang, LIU Hong-lei, YU Ge
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 49-56. DOI:10.13190/j.jbupt.2017.02.008
  • Abstract ( 311 )     HTML     　　
  • Two approaches are proposed to process the constraint event stream with uncertain timestamps. The query processing approach based on possible worlds can obtain the results by scanning the possible worlds according to the semantic of the constraint events. The query processing approach based on constraint event priority calculates the joint probability density of event timestamps, furtherly, calculates the marginal probability density of events in the composited query, and finally processes the query according to the query processing technology for the uncertain timestamp events. Experiments verify that both the query processing approaches for constraint event streams with uncertain timestamps are effective, and due to the smaller possible worlds, the query processing approach based on constraint event priority is more efficient than the query processing approach based on possible worlds.
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  • Generating Dummies Based on Gravity Model for User's Trajectory Privacy
  • ZHANG Cui
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 57-66. DOI:10.13190/j.jbupt.2017.02.009
  • Abstract ( 374 )     HTML     　　
  • The real-time location privacy preserving is a hotspot in continuous Location-Based Services (LBSs). A client-based dummy trajectory generation method is proposed. Based on the spatial grid partition, the history data in each cell of this grid is analyzed. Using the gravity model, a prediction model for users' movement pattern is built. Combined with the movement pattern model and the history query probability, the author defines a trajectory entropy to metric the trajectory privacy level. Based on k-anonymity principle, a limited velocity dummy trajectory generation algorithm with maximum trajectory entropy is proposed. Experiments from synthesis data and real-world data validate the effectiveness of our proposed method.
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  • Optimization of Link Quality Parameter Based on Dynamic Intuitionistic Fuzzy Multiple Attribute
  • LIU Lin-lan, HU Gang, LIU Song, LIU Wen-bo, GUO Na
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 67-72. DOI:10.13190/j.jbupt.2017.02.010
  • Abstract ( 377 )     HTML     　　
  • To select typical and comprehensive parameters reflecting link quality, an optimization approach was proposed based on dynamic intuitionistic fuzzy multiple attribute decision making. Considering stability and agility of link quality estimation, a method for order preference by similarity to an ideal solution was employed to get sorted parameters in candidate set according to decision making matrix coming from four different link levels, so that parameters are selected from sorted parameters. Based on the closeness of selected parameters, the selected parameters are fused with weighted average so as to achieve optimized link quality parameter which is the quality indicator based on dynamic intuitionistic fuzzy multiple attribute decision making (DMD-LQI). Experiments show that comparing with smoothed packet reception ratio (SPRR), fuzzy link quality estimator (F-LQE), the optimization approach is of better stability and agility.
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  • Improved Just Noticeable Model with Saliency Map
  • XIAO He, TU Qin, MEN Ai-dong
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 79-83. DOI:10.13190/j.jbupt.2017.02.012
  • Abstract ( 522 )     HTML     　　
  • Based on existing saliency detection algorithm, a model of joint estimation just noticeable distortion(JND) was proposed. This model not only makes full use of the advantage of the JND model, based on pixel domain and transform domain, but also employs the character of human visual system. The saliency detection algorithm used for saliency map, is employed to assign different weights to JND model, based on different brightness and color. The JND model based on pixel domain is mainly used on plain area, and the JND model, with masking effect and contrast sensitivity function, based on transform domain is used on texture area. The proposed model is introduced into the HEVC sample platform HM16.4. Experiments show that the proposed JND model, compared to HEVC standard, have the similar subjective quality.
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  Reports

  • 3-D 2×2×2-grid Scroll Chaotic System and Its Circuit Implementation
  • MA Ying-jie, LI Ya, XIE Rong-na
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 84-87. DOI:10.13190/j.jbupt.2017.02.013
  • Abstract ( 534 )     HTML     　　
  • Based on the classical Jerk chaotic system and the latest research of multi-scroll chaotic system, a model of the new chaotic system was constructed to produce 3-D grid multi-scroll chaotic attractors with the sign function in the modified Jerk's circuit. Both model analysis and Matlab simulation show that the system generates 3-D 2×2×2-grid multi-scroll chaotic attractors. Finally, the design of the hardware circuit was made at 3-D 2×2×2-grid multi-scroll hardware experiments. Hardware experiments. Analysis and simulation are full matched that is proven the physical realization of the system.
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  • Lay Length Optimization for Communication Cable Using NSGA-Ⅱ
  • LI Peng, LIU Yuan, WANG Yu-hua
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 88-92. DOI:10.13190/j.jbupt.2017.02.014
  • Abstract ( 406 )     HTML     　　
  • Lay length of communication cable was optimized using non-dominated sorting genetic algorithm-Ⅱ (NSGA-Ⅱ). Two object functions of communication cable dosage and near-end cross talk attenuation were designed. The solutions over diversified Pareto front were obtained. Lay length of communication cable with 25 pairs was studied as the optimization object. It is shown that 157 solutions are obtained and the dosage is in the range of[55.93 kg/km, 56.74 kg/km], the near-end cross talk attenuation is in the range of[58.11 dB/km, 94.77 dB/km]. The superiority of NSGA-Ⅱ is verified compared with particle swarm optimization. The convergence time of NSGA-Ⅱ and PSO are similar, the solutions of NSGA-Ⅱ are 100% better than PSO and distribute more evenly.
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  • Compact Parallel Coupled Line Band-Pass Filter Design with Open Stub
  • LA Dong-sheng, GUO Jing-wei, LIU Yan, JIA Shou-qing, MA Xue-lian
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 93-96. DOI:10.13190/j.jbupt.2017.02.015
  • Abstract ( 624 )     HTML     　　
  • In order to solve harmonic suppression, a parallel coupled line band-pass filter with simple structure was proposed. The filter consists of parallel coupled lines and open stubs. Filter's equation was firstly obtained via odd-even mode analytical method, which is based on the equivalent circuit of the proposed coupled line band-pass filter, and a compact band-pass filter was designed. Secondly, the relationship between filter's resonant characteristics and its electrical parameters was analyzed. And then, the geometric parameters of the proposed band-pass filter was obtained and optimized. Finally, the proposed band-pass filter and measured its S parameters was fabricated, which were basically consistent with simulation. It is founded that the filter designed has the advantages of simple structure, small size, etc. The proposed band-pass filter also has a wide stop band rejection and better selectivity through the introduction of transmission zeros.
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  • Seed-Based Data Dissemination in Campus MSNets
  • WANG Qing-shan, TANG Ying, WANG Qi, WANG Di, CHEN Li-jun
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 97-101. DOI:10.13190/j.jbupt.2017.02.016
  • Abstract ( 333 )     HTML     　　
  • In mobile social networks (MSNets), the packet is propagated through the intermittently connectivity which is established when two human-carried wireless-enabled devices are within communication range of each other. In order to use the intermittently connectivity to disseminate the packet, a seed-based data dissemination (SDD) algorithm was proposed in campus MSNets. The main idea is to choose a seed node for each community and use the seed node in data dissemination. Simulations show that, compared with the Epidemic algorithm, the publish/subscribe system and social groups based routing, SDD algorithm could reduce network overhead significantly, and near to the maximum delivery ratio obtained by the Epidemic algorithm.
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  • Identifying Apps Based on User-Agent and Web-Knowledge
  • GUI Xiao-lin, LIU Jun, QIAO Yuan-yuan, CHI Mu-cong, LEI Zhen-ming
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 102-105. DOI:10.13190/j.jbupt.2017.02.017
  • Abstract ( 362 )     HTML     　　
  • A new method was proposed to identify apps via analyzing network traffic.This method can identify apps according to incomplete and ambiguous features of user-agent. Firstly, the user-agents from hyper text transfer protocol headers was extracted; then, the related text feature was obtained from Internet by using the corresponding user-agent; finally, the apps by analyzing the obtained text features was identified. Experiments are conducted by using hyper text transfer protocol traffic traces collected from Gn interface. It is shown that the proposed techniques are superior to the known methods.
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  • User Similarity Collaborative Filtering Algorithm Based on KL Divergence
  • WANG Yong, DENG Jiang-zhou
  • Journal of Beijing University of Posts and Telecommunications. 2017, 40(2): 110-114. DOI:10.13190/j.jbupt.2017.02.019
  • Abstract ( 382 )     HTML     　　
  • User similarity based collaborative filtering algorithm is one of most widely used technologies. Most of user similarity algorithms only consider the co-rated items between two users, but ignore other ratings that probably hide valuable information. To evaluate user similarity accurately, a user similarity collaborative filtering algorithm based on Kullback-Leibles (KL) divergence was proposed. The proposed algorithm utilizes both the co-rated items and the influence of other no co-rated items. Since the algorithm makes full use of all rating information, it improves the accuracy and reliability of user similarity. Experiments show that the proposed algorithm outperforms other user similarities. Moreover, it can still measure the user similarity effectively, even if no co-rated items exist. Therefore, the presented algorithm solves the problem of full dependence on co-rated items and gains better flexibility.
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