聂敏 陶金 杨光 孙爱晶 裴昌幸
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0025
Traditional virtual private networks (VPNs) are conditional security. In order to ensure the security and confidentiality of user data transmission, a model of quantum VPN based on Internet protocol security (IPSec) protocol is proposed. By using quantum keys for key distribution and entangled particles for identity authentication in the network, a secure quantum VPN is relized. The important parameters affecting the performance of the VPN was analyzed. The quantitative relationship between the security key generation rate, the quantum bit error rate (QBER) and the transmission distance was obtained. The factors that affect the system throughput were also analyzed and simulated. Finally, the influence of the quantum noise channel on the entanglement swapping was analyzed. Theoretical analysis and simulation results show that, under a limited number of decoy states, with the transmission distance increased from 0 to 112.5 km, the secure key generation rate was reduced from 5.63×10-3 to1.22×10-5 . When the number of decoy states is fixed, the QBER increases dramatically with the increase of the transmission distance, and the maximum reaches 0.393. Analysis shows that various factors in communication have a significant impact on system throughput. The generation rate of the effective entanglement photon pairs have decisive effect on the system throughput. Therefore, in the process of quantum VPN communication, various parameters of the system should be properly adjusted to communicate within a safe transmission distance, which can effectively improve the reliability of the quantum communication system.
宋成 张亚东 王磊 刘志中
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0021
Aimed at enhancing privacy protection of location-based services (LBS) in mobile Internet environment，an improved privacy scheme of high service quality on the basis of bilinear pairings theory and k-anonymity is proposed. In circular region of Euclidian distance, mobile terminal evenly generates some false locations, from which half optimal false locations are screened out according to position entropy, location and mapping background information. The anonymity obtains the effective guarantee, so as to realize privacy protection. Through security analyses, the scheme is proved not only to be able to realize such security features as privacy, anonymity and non-forgeability, but also able to resist query tracing attack. And the result of simulation shows that this scheme not only has better evenness in selecting false locations, but also improves efficiency in generating and selecting false nodes.
刘振华 袁冬 刘要辉 李园园
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0026
As a kind of cryptocurrency, bitcoin has attracted much attention with its decentralization. However, there is two problems in the bitcoin transactions: the account security and transaction privacy. In view of the above problems, a new partially blind threshold signature scheme is proposed, which can both enhance the security of bitcoin account and preserve the privacy of transaction. Firstly, transaction amounts are encrypted by employing the homomorphic Paillier cryptosystem, and output address is disturbed by using one-time public key. Then the encrypted or disrupted transaction information is signed by multiple participants who are authorized by using threshold secret sharing. Compared with partially blind fuzzy signature scheme, the proposed scheme can fully preserve the transaction privacy. Furthermore, performance analysis shows that the proposed scheme is secure and effective in practical applications.
袁江伟 李晓辉 蒲文娟 杨胥
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0031
Hybrid beamforming (HBF) technology becomes one of the key technologies in the millimeter wave (mmWave) mobile backhaul systems, for its lower complexity and low power consumption compared to full digital beamforming (DBF). Two structures of HBF exist in the mmWave mobile backhaul system, namely, the fully connected structures (FCS) and partially connected structures (PCS). However, the existing methods cannot be applied to both structures. Moreover, the ideal phase shifter is considered in some current HBF methods, which is not realistic. In this paper, a HBF algorithm for both structures based on the discrete phase shifters is proposed in the mmWave mobile backhaul systems. By using the principle of alternating minimization, the optimization problem of HBF is decomposed into a DBF optimization problem and an analog beamforming (ABF) optimization problem. Then the least square (LS) method is enabled to solve the optimization model of DBF. In addition, the achievable data rate for both structures with closed-form expression which can be used to convert the optimization model into a single-stream beamforming optimization model with per antenna power constraint is derived. Therefore, the ABF is easily solved. Simulation results show that the performance of the proposed HBF method can approach the full DBF by using a lower resolution phase shifter.
梁晓林,曹旺斌, Zhao Xiongwen
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0033
A geometry-based stochastic scattering model (GBSSM) based on geometrical multiple rings and ellipses is proposed for wideband multiple-input multiple-output (MIMO) mobile-to-mobile (M2M) fading channels. The proposed GBSSM is deployed with cross-polarized antennas and can be applied for the line-of-sight (LOS) and non-LOS (NLOS) scenarios by considering the single-bounced (SB) and double-bounced (DB) components. The channel realization is much more straightforward and concise to study the channel characteristics compared with the too complicated analytical solutions available so far. Based on the proposed GBSSM and realized channel, the channel characteristics and parameters at 2 GHz and 5 GHz with 100 MHz bandwidth are further investigated. The results can be used in the link and system level simulations in mobile-to-mobile radio systems.
朱晓荣 董天才 Wang Yong
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1885-8885.2018.0034
Some emerging services such as augmented/virtual reality need high data rates. Whereas, the existing 2nd Generation (2G), the 3rd Generation (3G) and the 4th Generation (4G) networks cannot provide such high transmission rates. To meet these requirements, in this paper, the technology and the realization of a “virtual super terminal” that can perform the concurrent streaming of video via the cooperation of multiple heterogeneous terminals are introduced. This paper uses concurrent streaming scheduling algorithm, buffer overhead and packet delivery method, and packet loss prevention and recovery method to improve the performances of the system. Testbed measurements show that compared with the scheme without cooperative transmission this new design can significantly increase system throughput and decrease packet delay.
范馨文 温向明 路兆铭 孙春蕾 韩曦
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0029
Currently, the Photovoltaic (PV) cloud network is an important research point in energy Internet. From the perspective of the robustness analysis of PV cloud network, traditional robustness index, the relative size of the giant connected component before and after the cascading , which is focused on the giant component, is not appropriate for the distributed PV network because of the big difference between PV generators and large power grid. In this paper, a new index is proposed, the minimum removed nodes number (MRNN), which can make the entire system collapse, to evaluate the robustness of PV cloud network system. The simulation results show MRNN can clearly indicate the system robustness under different parameters.
李齐山 胡智群 温向明 路兆铭 亓航
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0023
The popularity of IEEE 802.11 based Wireless Local Area Network (WLAN) increased significantly in recent years and resulted in the dense deployment of WLANs. While densification can contribute to increasing coverage, it could also lead to increasing interference and cannot insure high spatial reuse due to the current physical carrier sensing of IEEE 802.11. To tackle these challenges, the dynamic sensitivity control (DSC) is considered in IEEE 802.11ax, which dynamically selects the appropriate carrier sensing threshold (CST) to improve spectrum efficiency and enhance spatial reuse in densely deployed network. A dynamic Q-learning based CST selection method is proposed to enable a network to select the optimal CST according to the channel condition. Simulation results show that the propsoed scheme provides 40% aggregate throughput gain of a dense network when compared with legacy IEEE 802.11.
张志鹏 陈增强 刘忠信
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0028
The compatible-invariant subset of deterministic finite automata (DFA) is investigated to solve the problem of subset stabilization under the frameworks of semi-tensor product (STP) of matrices. The concepts of compatible-invariant subset and largest compatible-invariant subset are introduced inductively for Moore-type DFA, and a necessary condition for the existence of largest compatible-invariant subset is given. Meanwhile, by using the STP of matrices, a compatible feasible event matrix is defined with respect to the largest compatible-invariant subset. Based on the concept of compatible feasible event matrix, an algorithm to calculate the largest compatible-invariant subset contained in a given subset is proposed. Finally, an illustrative example is given to validate the results.
赵晶 谢怡宁 卢玉 何勇军
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0027
Image segmentation directly determines the performance of automatic screening technique. However, there are overlapping nuclei in nuclei images. It raises a challenge to nuclei segmentation. To solve the problem, a segmentation method of overlapping cervical nuclei based on the identification is proposed. This method consists of three stages: classifier training, recognition and fine segmentation. In the classifier training, feature selection and classifier selection are used to obtain a classifier with high recognition rate. In the recognition, the outputs of the rough segmentation are classified and processed according to their labels. In the fine segmentation, the severely overlapping nuclei are further segmented based on the prior knowledge provided by the recognition. Experiments show that this method can accurately segment overlapping nuclei.
中国邮电高校学报(英文版), 2018, 25 (5). doi： 10.19682/j.cnki.1005-8885.2018.0024
The distributed parameters of the transmission lines have the significant impact to the signal propagation. In the conventional method of the distributed parameter extraction, the discontinuity of inverse trigonometric or hyperbolic can arise the problem about phase ambiguity which causes significant errors for transmission models. A difference iteration method (DIM) is proposed for extracting distributed parameters of high frequency transmission line structure in order to overcome the phase ambiguity in the conventional method. The formulations of the proposed method are first derived for two-conductor and multi-conductor lines. Then the validation is performed for the models of micro-strip transmission line. Numerical results demonstrate that the proposed difference iteration method can solve the problem about the phase ambiguity and the extracted distributed parameters are accurate and efficient for a wide range of the frequencies of interest and line lengths.