Current Issue

• • 2004, Vol. 27 No. 1 Published date:28 January 2004 Last issue Next issue

  SUMMARIZATION

  • Research on Service Feature Interactions in Telecommunication Networks
  • YANG Fang-chun, XU Jiu-yun
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 1-7.
  • Abstract ( 268 )     HTML     　　
  • Major methods of researching on service feature interactions are described in detail: One of them is static detection which uses formal description technique tospecify services and telecommunication system in order to detect service feature interaction off-line, as well as to resolve them with redesigning services; The other is to detect feature interactions on-line and resolve the feature interactions at run-time. Based on the analysis of current researches on the service interactions in telecommunications service of the past decade, the advantagesand disadvantages of the above methods are discussed. Furthermore the key factors to be considered in service interaction of NGN (next generation networks) anda new way to study feature interaction in terms of artificial immune are proposed.
  • References | Supplementary Material | Related Articles

  PAPERS

  • Sum-Frequency Generation Converter Wavelength Analysiswith Periodical Structure Medium
  • LIU Gang, YU Chong-xiu, YANG Xiang-dong,
    ZHANG Ru, LU Yu-qin
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 8-12.
  • Abstract ( 364 )     HTML     　　
  • A theoretical model of wavelength conversion based on Sum-Frequency GenerationQuasiphase-Matched in nonlinear medium with periodically structure is established. For example, AlGaAs, using this model, the simulation of the numerical value relationship of device length and conversion efficiency for different transmission loss is given, as well as the relationship of pump power and conversion wavelength power. Results show that pump power, transmission loss and device length are main factors in the process of conversion.
  • References | Supplementary Material | Related Articles

  • An Improved Hybrid Method for Modeling Indoor Radio Propagation
  • HUANG Yong-ming, LU Ying-hua, XU Li, FENG Xiao-jun,
    ZHANG Hong-xin
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 13-17.
  • Abstract ( 235 )     HTML     　　
  • A hybrid method of combing ray tracing and finite-difference time-domain (FDTD) method is improved. This method is used to indoor radio propagation numericalmodeling work. The difference equations of the perfectly matched layer (PML) absorbing boundary conditions used in the hybrid method are given. An example is calculated and the resultant graphs reveal that the improvement can reach 15 percent. So, more accurate propagation prediction can be obtained by using the improved method.
  • References | Supplementary Material | Related Articles

  • The Mathematical Model of the Fabry-Perot Filter
  • QI Yong-xing, CHEN Shu-qiang, LIU Yuan-an, QIAN Zong-jue,
    ZHAO Guo-qian
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 18-20.
  • Abstract ( 276 )     HTML     　　
  • Applying some knowledge of signal and system to the Fabry-Perot (FP) filter analysis and design, a new method is proposed which eliminates the complex matrix calculation. Furthermore, as being associated with the whole system and characterized by a transfer function, FP cavity filter is easy to be comprehended and to be optimized.
  • References | Supplementary Material | Related Articles

  • Relationships Management among Technology Special Networks in Multi-Technology Networks
  • ZHAN Zhi-qiang, QIU Xue-song, MENG Luo-ming
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 21-25.
  • Abstract ( 267 )     HTML     　　
  • After proposed the problem of relationships management among technology specialnetworks in multi-technology networks and its importance, a few aspects about network relationships management are discussed, including the information classification, characteristics, model and management mode of the networks relationships.
  • References | Supplementary Material | Related Articles

  • An Algorithm for Admission Control in WCDMA Multi-Services System
  • PEI Ting-rui, ZHOU Sheng, WU Wei-ling
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 26-30.
  • Abstract ( 251 )     HTML     　　
  • The traditional call admission control (CAC) strategy could not be applied inWCDMA multi-services system effectively. The synthesis CAC algorithm (S-CAC)was put forward for WCDMA multi-services system based on the analyzing of those traditional CAC algorithms. The evaluation of the algorithm was done using theWCDMA system-level simulation bench at last.
  • References | Supplementary Material | Related Articles

  • Performance Analysis of an Adaptive Modulation System over Fading Channels
  • LEI Ming, XU Yue-shan, CAI Peng, ZHANG Ping
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 31-35.
  • Abstract ( 319 )     HTML     　　
  • The performance of the adaptive modulation system over Nakagami fading channelsis analyzed, which utilizing four modulation modes. The optimization criterion of the setting of the modulation switching levels is to maintain the target BER,which is desired by many data services. Under this condition, the performance analysis of the throughput and the transmission outage probability of the adaptivemodulation system are presented. We do so by adopting the numerical analysis methods. Finally, the simulation results show that the adaptive modulation systemcan theoretically achieve high throughput performance, and low transmission outage probability under certain conditions.
  • References | Supplementary Material | Related Articles

  • Timing Recovery and Frequency Offset Estimation for OFDM System
  • LI Wei-hua, ZHANG Bei-lei, WU Wei-ling
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 36-39.
  • Abstract ( 261 )     HTML     　　
  • O FDM is sensitiv e to timing recovery and f requency of f set estimatio n, current no n-da ta-aided estimation methods do n 't w o rk w ell on multipath cha nnel. Based on the analy sis of the current methods, a new method i s pro po sed and simulated. The simula tion result s show that the mean square erro r of the timing and f requency o ff set estima tion for pro posed method i s superior to that of the max imum likelihood and ensemble correlatio n methods.
  • References | Supplementary Material | Related Articles

  • Traffic Protection Method in the All Optical Network
  • WANG Jian-quan, GU Wan-yi, LU Chao
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 40-44.
  • Abstract ( 209 )     HTML     　　
  • Typical method of protection and restoration in current telecommunication network is analyzed carefully, and resource utilization, implementation time and complexity is compared and analyzed in applicable scope. In optical network, the implementation time and efficiency of the network resource are important in survivability. Taking the merits of various protection and restoration into account, a method for protection based on traffic can be proposed. 1∶1, shared path protection method and ring network channel protection are analyzed and studied in detail. The proposed protection method based on traffic can not only meet the requestof time of survivability but also make the protection granularity diversification, which provide more choice for protection. What is more, the realization scheme and process of these several traffic protection methods are proposed in detail.
  • References | Supplementary Material | Related Articles

  • Space-Time Block Codes Design in OFDM System
  • LUO Tao, TENG Yong, TONG Xue-jian, YUE Guang-xin
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 45-49.
  • Abstract ( 231 )     HTML     　　
  • Using redundant pre-coding, a novel method, pre-coding STBC-OFDM system, combining the space-time block codes and OFDM smoothly in frequency selective fading channel is proposed. In addition, the minimum distance sphere up-bound of this system is also obtained. Results show that the attractiveness of this pre-coding STBC-OFDM system in frequency selective channel is in its ability to exploit all the available diversity resources. In other words, the highest possible diversity order this pre-coding STBC-OFDM system can provide is the product ofthe number of transmitter antennas, the number of receiver antennas and the number of selective fading diversity order.
  • References | Supplementary Material | Related Articles

  • A New Method of Blind Beamforming for CDMA System
  • LU Jing-yang, WU Wei-ling
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 50-54.
  • Abstract ( 276 )     HTML     　　
  • A receiver model is developed on a direct-spread code-division multiple-access system, and a blind beamforming algorithm is proposed based on the model. Therelationship of the subspace of the received signal and the spreading code of the desired user is used to get coefficient of beamformer. Simulations have demonstrated that the algorithm performs better than other blind beamforming algorithms.
  • References | Supplementary Material | Related Articles

  • Approach to Define SDL Static Semantics with Basic ASM
  • ZHAO Yu-hong, AI Bo
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 55-59.
  • Abstract ( 255 )     HTML     　　
  • A formal method to define the static semantics of SDL (specification and description language) using basic ASM(abstract state machine) is presented. Main features of this method are that elements in syntax domains can be interpreted uniquely as syntax values; transformation rules can be defined as ASM rules; mapping rules can be defined as a series of mapping functions called t-functions.
  • References | Supplementary Material | Related Articles

  REPORTS

  • Intelligent Value-Added Service Platform Based on Parlay
  • QIAO Xiu-quan, LI Xiao-feng, XU Hui-min
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 60-64.
  • Abstract ( 235 )     HTML     　　
  • Parlay, a softswitch-based open service interface specification of NGN (next generation network), is briefly introduced firstly. Making reference to call control model of Parlay, a scheme that improves on service development of intelligentservice platform is presented.
  • References | Supplementary Material | Related Articles

  • The Interlinking of SCPs over Different Telecommunications Networks
  • LIU Wen-feng, LIAO Jian-xin, ZHU Xiao-min
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 65-69.
  • Abstract ( 292 )     HTML     　　
  • Three different plans to link intelligent networks in fixed net, CDMA, and GSM are presented. This proposal allows multiple types of intelligent networks to exchange user information and control flow. The article compares two proposals forinterlinking and puts up one optimal plan, which contains advantages of IP linkage and No.7 linkage. This technique can be realized in an easy way and be commercialized in a short time.
  • References | Supplementary Material | Related Articles

  • The Key Technologies for the Location Based Service in Wireless Intelligent Network
  • WANG Hui, LIAO Jian-xin, ZHOU Jun-feng
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 70-74.
  • Abstract ( 206 )     HTML     　　
  • Based on the study of the characters of the trigger mechanism in wireless intelligent network and the current state of the location based services, the application for the LBS on WIN is analyzed, and the corresponding solutions are presented to the key technologies in the application.
  • References | Supplementary Material | Related Articles

  • Module Wireless Communication Design for Robot Basing on Bluetooth
  • XIAO Ai-ping, SUN Han-xu, TAN Yue-sheng
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 75-78.
  • Abstract ( 219 )     HTML     　　
  • A module-communication method basing on bluetooth technology is presented, which solves the wireless communication problem for a shortrange robot. The said method includes two aspects, one is about software, which partitions bluetooth protocol stack, performs various functions such as query, qualification, connection and communication, etc, and defines the format of the serial data frames, and thereby forms a wireless transparent channel, the other is about hardware, which provides a standard serial port. It simplifies the design of robot wireless communication, and enhances the reliability of communication.
  • References | Supplementary Material | Related Articles

  • Research of Large-Scale Network-Based AdaptiveIntrusion Response Model
  • GUO Dai-fei, YANG Yi-xian, HU Zheng-ming
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 79-83.
  • Abstract ( 267 )     HTML     　　
  • State of art of intrusion response is analyzed before a new classified method ofintrusion response is proposed. A new adaptive intrusion response model is built which adopts XML to describe complex attack in heterogeneous network, fuses intrusion data with Theory of Evidence and responds based on Theory of Cost Sensitive Response. The problems of intrusion response system in large-scale networkare discussed.
  • References | Supplementary Material | Related Articles

  • Conversion from XML Documents to Database
  • DENG Fang
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 84-88.
  • Abstract ( 268 )     HTML     　　
  • A method to convert extensible markup language (XML) documents to data stored in database is discussed. A example is given baesd on which ways from XML Schema to relational and object-relational database are implemented.The ways can be applied to data exchanging and integration.
  • References | Supplementary Material | Related Articles

  • The Development of XML Parser in XML-Based Network Management Conformance Test
  • DONG Wen-li, MENG Luo-ming, LIN Wei, NING Kai, CHEN Yi-gen
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 89-92.
  • Abstract ( 282 )     HTML     　　
  • XML parse is the key part of XML-based network management interface conformance test, the paser can read and parse a XML file. According to XML characteristic, XML parser suitable for XML network management conformance test is developed.This parser can carry on morphological analysis, syntactic analysis and semanticanalysis to XML file, and can offer the data information for test system.
  • References | Supplementary Material | Related Articles

  • Clustering Algorithms of MANET and Performance Comparisons
  • WANG Hai-tao
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 93-97.
  • Abstract ( 247 )     HTML     　　
  • The architectures and existent problems of Ad hoc networks are expounded. Several typical clustering algorithms in Ad hoc network are discussed. Performance comparisons and analysis between those algorithms are performed by simulation in different network environments. A summarization is given.
  • References | Supplementary Material | Related Articles

  • An Approach to Supporting QoS Levels in MPLS VPN
  • LIN Hua-sheng, WANG Wen-dong, LIN Yu, CHENG Shi-duan
  • Journal of Beijing University of Posts and Telecommunications. 2004, 27(1): 98-102.
  • Abstract ( 241 )     HTML     　　
  • Presently MPLS VPN adopts VPN multiplex model based on two-level label stack toforward packets, which improves the scalability of system but at the same timelimits its ability to provide the strict QoS guarantee to up layer applications.This paper proposes a new approach to support QoS Levels in MPLS VPN, and the main QoS control mechanisms used in the approach are also discussed.
  • References | Supplementary Material | Related Articles