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The User-level Security of Mobile Communication Systems

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The Journal of China Universities of posts and telecommunications 2002年第3期9卷 62-69页

作者： DUAN Lian, ZHANG Hao liang, WU Wei ling (Information Engineering school,beijing {2. of posts and telecommunications,beijing 100876, P.R. China) Information Engineering school Beijing University of Posts and TelecommunicationsBeijing 100876 P.R. China

This paper studies the user-level security of mobile systems . The currentmobile phone users trust the invisible security of the 2. systems. The evolution from thesecond-generation mobile systems (2.) to the third generation systems (3G) will introduce thethreats and opportunities of the Internet to the world of mobile communications. From the technicalpoint of view, the new security requirements are similar to the security requirements met with todayin a company Intranet environment. There is, however, one great difference; the charge paid foraccessing the service. In future the users of mobile systems will have to be more aware of thesecurity issues.

关键词： security mobile communication system user

Environment Factors and Development Policies in Chinese Rural telecommunications

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The Journal of China Universities of posts and telecommunications 2003年第4期10卷 101-106,114页

作者： WU Hong,LIANG Xiong-jian(Institution of Information Management science and Information Economics, beijing university of posts and telecommunications,{2., P.R. China) Institution of Information Management science and Information Economics Beijing University of Posts and Telecommunications 北京 100876

Rural telecom development is one of the focal points now. The favorable and unfavorable factors for rural telecom development will coexist with each other in the following years. There are also differences of development between urban telephone service and rural one. This paper studies all these factors and points out the policies for rural telecom development.

关键词： rural telephone environmental factors critical mass

The Research and Application Design of SDL Protocol

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The Journal of China Universities of posts and telecommunications 2001年第3期8卷 39-45页

作者： WEN Xiang-ming, YIN Han, ZHU Xiang-hua (Continuing Education school of beijing university of posts and telecommunications,{2.,P.R.China) Continuing Education school of beijing university of posts and telecommunications

Aiming at overcoming the disadvantages in the Simple Data Link(SDL) protocol, we study and modify the protocol mechanism, which enhances the flexibility in carrying the packets of various network layer protocols and improves the ability to correct errors. We research the error check and error correction of CRC and the application of MPLS labels in the SDL protocol. Furthermore, we provide a method of CRC correction and application of MPLS labels in the SDL protocol. Finally, we present a scheme of realizing the SDL protocol.

关键词： SDL MPLS CRC

A Difference Method of the Gravity Center with Double Pilots for the MC CDMA System

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The Journal of China Universities of posts and telecommunications 2000年第4期7卷 62-67页

作者： LI Xiang ming, YUE Guang xin, YIN Chang chuan (school of Telecommunication Engineering, beijing university of posts and telecommunications,{2., P.R. China) school of Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 P.R. China

A carrier recovery method of the power spectrum center difference adapting to the mobile channel of the MC CDMA system with serious Doppler shift using double pilots is presented. In the transmitter, two pilots of equal frequency distance to the carrier with one putting on the left position and the other on the right position of the carrier frequency are used. Even if a continuous sine wave is transmitted, the power spectrum is expanded to a Doppler band in the receiver owing to the multi path transmission and the Doppler shift. The pilot spectrum is made to pass through two narrow band filters which are transformed to the base band with local carrier wave in the receiver. The frequency difference between the local carrier and the transmitter carrier is obtained when the difference of the gravity centers of the two pilot spectra is computed.

关键词： orthogonal frequency division multiplexing MC CDMA carrier frequency synchronization timing synchronizati(

Multi-layer network architecture in support of end-to-end transparent optical connectivities

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science China(Information sciences) 2011年第3期54卷 674-682页

作者： GUO HongXiang , WU Jian, HONG Xiao Bin & LIN Jin Tong Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, beijing university of posts and telecommunications, beijing 100876, China Key Laboratory of Information Photonics and Optical Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing China

In order to effectively accommodate a wide variety of emerging and future applications with diverse requirements, an intelligent optical network capable of the rapid and resilient delivery of on-demand transparent transmission capacity is required. This paper investigates a multi-layer network architecture where a generalized multiple protocol label switching (GMPLS) controlled transparent wavelength switched optical network (WSON), as the transport core, collaborates with multiple client optical burst switching (OBS) networks distributed at the edge. Dynamic interworking mechanism as well as the related signaling/routing protocol ex- tensions for multi-QoS burst streams transmission among different OBS domains are proposed so as to provision an end-to-end (e2.) transparent optical connectivity with on-demand bandwidth to end-users. Moreover, the survivability of this transparent optical connectivity is also addressed. To validate the feasibility of this architecture, an integrated OBS/WSON network testbed was constructed, and stable e2. transparent connectivities were successfully demonstrated for an efficient multi-QoS burst streams transmission.

关键词： multi-layer network transparent optical network OBS WSON GMPLS

Decentralized Control of Dynamic Routing with a Neural Network Algorithm

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The Journal of China Universities of posts and telecommunications 2000年第1期7卷 46-50页

作者： XIN Zhan-hong, FANG Mei-qin (school of Management and Humanities, beijing university of posts and telecommunications,{2., P. R. China) school of Management and Humanities Beijing University of Posts and Telecommunications Beijing 100876 P. R. China

A state-dependent routing algorithm based on the neural network model, which takes advantage of other dynamic routing algorithm for circuit-switched network, is given in [1]. But, the Algorithm in [1] is a centralized control model with complex O (N 7), therefore, is difficult to realize by hardware. A simplified algorithm is put forward in this paper, in which routing can be controlled decentralizedly, and its complexity is reduced to O (10N 3). Computer simulations are made in a fully connected test network with eight nodes. The results show that the centralized control model has very effective performance that can match RTNR, and the centralized control model is not as good as the centralized one but better than DAR-1.

关键词： neural network circuit-switched network dynamic routing decentralized control

Dynamic call and connection admission control in automatically switched optical network for grid computing applications

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science China(Information sciences) 2012年第2期55卷 419-432页

作者： LIU Lei,GUO HongXiang,HONG XiaoBin,WU Jian & LIN JinTong Key Laboratory of Information Photonics and Optical Communications,Ministry of Education,beijing university of {2. and telecommunications,beijing 100876,China Key Laboratory of Information Photonics and Optical Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing China

In recent years,Grid computing applications are becoming more and more important to the scientific and business communities and are likely to open to the consumer market and widely develop in the near future,which is a great challenge brought by the potentially large number of Grid users(perhaps millions)and high frequency of their job *** switched optical network(ASON),which is a promising high capacity intelligent transport network infrastructure,has been already deployed in the world and regarded as a promising solution to foster the expansion of Grid computing from local area networks to wide area ***,by theoretical analysis and simulative evaluation of Grid job blocking in the distributed call and connection setup process of ASON,this paper verifies that ASON and the conventional admission control mechanism confront a problem in supporting future large-scale Grid *** order to address this issue,a novel dynamic call and connection admission control(DCCAC)scheme is proposed to improve the network performance and guarantee quality of service(QoS)of Grid *** scheme is applicable with complete network information,no network information and partial network *** results show that the DCCAC scheme can improve the efficiency of the network to a great ***,all the analysis and algorithms in this paper are based on ITU-T ASON recommendations,which make the DCCAC scheme more applicable in network engineering for future Grid computing.

关键词： automatically switched optical network(ASON) Grid computing blocking probability call admission control connection admission control

Multi-State Chaos-Shift-Keying Modulation System: Analysis and Realization

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The Journal of China Universities of posts and telecommunications 1997年第2期4卷 54-56,80页

作者： Zhang Yinghai, Liu Jie and Cai Tao (Department of Applied science and Technology, beijing university of posts and telecommunications,{2., P.R.China)

In this paper, a new type of chaos shift keying(CSK) modulation, called multi state CSK, is analyzed and tested. In this type of modulation combined with feedback synchronization, the data rate can be greatly incre... 详细信息

关键词： chaos modulation Chua's circuit

A Study of Self-adaptive X/Y Flow Classification Method in LER

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The Journal of China Universities of posts and telecommunications 2001年第2期8卷 51-55页

作者： SHAO Xu, DING Wei, SHI Jing lin (Continuing Education school, beijing university of posts and telecommunications,{2., P.R. China) Continuing Education school Beijing University of Posts and Telecommunications

According to the X/Y flow classification method based on TCP and UDP port, a new method named self adaptive X/Y flow classification method is proposed in the paper, which can make the curve of the ratio of label resource usage more stable than ever so as to improve the performance of both L3 forwarding and L2.label switching of LER in MPLS networks. With the simulation of real Internet data, a satisfactory classification result has been obtained.

关键词： IP MPLS LER flow classification self adaptive