Current Issue

• • 2002, Vol. 25 No. 4 Published date:10 November 2002 Last issue Next issue

  • Summarization of IPv4 to IPv6 Transition Mechanisms
  • MA Yan, ZHAO Xiao-yu
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 1-5.
  • Abstract ( 275 )     HTML     　　
  • The way for the further development of Internet is avery critical issue. This paper enumerated and compared some existing IPv4 to IPv6 transition mechanisms.
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  • Research on the Limitation of Higher-order PMD toHigh-speed Digital Fiber Communication Systems
  • ZHAO Wen-yu, WANG Hong-xiang, WANG Lan,JI Yue-feng, XU Da-xiong
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 6-10.
  • Abstract ( 270 )     HTML     　　
  • The definition of higher-order polarization mode dispersion (PMD) is presented firstly in this paper. Then, based on the numerical model of higher-order PMD introduced in it, the impact of higher-order PMD on the 40 Gbit/s NRZ systems is discussed with numerical simulation. The result shows that if the PMD is higher than 8ps, eye-opening penalty due to only higher-order PMD will be larger than 2 dB. This demonstrates that the effect of higher-order PMD on the high bit-rate digital fiber communication systems is very obvious and cannot be neglected.
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  • Analysis of Dynamic Bit Allocation Algorithm in OFDM System
  • JI Hong, HAO Jian-jun, TONG Xue-jian, YUE Guang-xin
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 11-15.
  • Abstract ( 228 )     HTML     　　
  • A new DAB algorithm model with constraints of given transmission rate and QoS requirement is proposed in the paper, as well as be applied to OFDM system. Compared with the conventional equal bit allocation method, the DBA method can improvethe system performance greatly by analysis and numerical simulation.
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  • An Adaptive Mobile Multicast Protocol
  • FAN Rui, YANG Jian, CHENG Shi-duan
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 16-20.
  • Abstract ( 214 )     HTML     　　
  • This paper presents an adaptive mobile multicast protocol which combines the advantages of MMA and Mobicast protocol. This protocol can flexibly change the mode multicast packets sent according to network conditions and thus enables the system resources to be used optimally.
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  • Enumeration of Resilient Functions
  • WEN Qiao-yan, YANG Yi-xian
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 21-25.
  • Abstract ( 201 )     HTML     　　
  • Enumeration of resilient functions is discussed in this paper. By applying orthogonal array, the exact number of it is found for somespecial cases.
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  • User Mobility Model Based on Preferred Speed and Direction
  • DUAN Lian, ZHANG Hao-liang, WU Wei-ling
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 26-30.
  • Abstract ( 226 )     HTML     　　
  • User mobility plays a great role in analysing performance of wireless network. By studying speed and direction of user movement, a user mobility model based on prefered speed and direction is proposed, which makesuser movement purposeful and random. So this model accords better with the reality. Consequently, it is to manage radio resource of wireless network and user mobility more efficiently.
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  • A WBEM-based Integrated Network Management Architecture
  • BI Feng, QIU Xue-song, MENG Luo-ming
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 31-35.
  • Abstract ( 209 )     HTML     　　
  • Based on the analysis of the four ways of integratingthe network management systems and the comparison of the merits and disadvantages of conventional network management architectures in managing hybrid network,a new WBEM based integrated network management architecture is provided and analyzed. According to this architecture, a solution of integrating the traditionalnetwork management systems based on the network management interface level is given, then the advantages and disadvantages of this solution are discussed.
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  • Intelligent Service Agent Supporting of IN/IP Integration
  • WANG Wen-dong, CHENG Shi-duan
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 36-41.
  • Abstract ( 220 )     HTML     　　
  • An Softswitch component-Intelligent Services Agent (ISA) supporting of IN/IP inter-working is proposed. Overlaid scheme which is used to build ISA is discussed. Some key technical issues, such as call states mapping and Messages conversion schemes, are presented. A free phone service in IN/IP inter-working environment is showed as an example to illustrate the ISA's working scenario.
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  • The Formal Model of a Simple Network Payment Protocol
  • ZHANG Ze-li, MA Hua-dong
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 42-46.
  • Abstract ( 302 )     HTML     　　
  • Focusing on the payment problem for the e-commerce,discusses on the simple network payment protocol (SNPP) is presented in this paper. By timed automata, the paper specifies the model of SNPP so as to analyze its properties and assure the reliable implementation of the payment system.
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  • On the Relationship Between the Round Key and the Cipher Key of the AES Algorithm
  • CAO Hua-ping, LUO Shou-shan, WEN Qiao-yan, YANG Yi-xian
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 47-50.
  • Abstract ( 264 )     HTML     　　
  • This paper presents the relationship between the round key and the cipher key ofthe AES algorithm and proposes a mathematical model of the key expansion of AES algorithm.
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  • The Handoff Algorithm Based on Signal Prediction for Mixed Service
  • ZHANG Chuan-fu, WU Wei-ling
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 51-55.
  • Abstract ( 217 )     HTML     　　
  • Handoff is an important issue in mobile communicationsystems that provide various multimedia services. In this paper, the performances of three soft handoff schemes were analyzed and compared for CDMA-based wireless packet voice/data networks.
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  • The Association Rule Mining Based on Item Numbers
  • DUAN Yun-feng, SONG Jun-de, LI Jian-wei, SHU Hua-ying
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 56-60.
  • Abstract ( 188 )     HTML     　　
  • With an analysis of the problems in association rulemining, a new concept with number of items is proposed. Based on the number-support, the Apriori algorithm is improved, and the result is compared with the newalgorithm.
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  • Analysis and Improvement of IPsec and NAT Compatibility
  • ZHENG Wen-hui, MA Yue, JIANG Yan-jun
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 61-64.
  • Abstract ( 208 )     HTML     　　
  • This article analyses the problem of IPsec and NAT compatibility, presents several methods according to this problem.
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  • A Matching Method of Homonymy Points on Image
  • CHEN Qing-jin, DENG Zhong-liang, HUANG Ming-ji
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 65-69.
  • Abstract ( 358 )     HTML     　　
  • Different ways to three-dimensional modeling are analysised, especially the methods and procedures of modeling based on image, the problems caused by the matching of homonymy point-pairs in the Image based Modeling are also discussed. A new method is advanced, which uses the key points to build a key polygon before constructs some homonymy point-pairs based on the polygon's comparability. The method's validity is also proved by using a experiment.
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  • A Improved Fair Off-line E-cash Scheme
  • XU Zhao, YANG Yi-xian
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 70-73.
  • Abstract ( 210 )     HTML     　　
  • A provably secure blind signature scheme is proposed.It is based on a partially blind signature. By applying it to fair e-cash, wepropose a secure fair off-line e-cash scheme, and analyse its security.
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  • Research on the Parallel Concatenated Space Time Trellis Code in Conjunction with Hybrid ARQ
  • GAO Lu, LI Wen-yu, WU Zhan-ji, WU Wei-ling
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 74-78.
  • Abstract ( 192 )     HTML     　　
  • The performance of parallel concatenated space time trellis code (PC-STTC) in conjunction with Hybrid ARQ protocols is investigated.The scheme to combine PC-STTC with Hybrid ARQ is proposed, in which turbo iterative decoder combines code diversity with MRC diversity for the retransmitted frames. The performance of the scheme in quasistatic flat Rayleigh channel and that of flat fast Rayleigh channel is studied by the monte carlo simulation.
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  • Rapid DOA Estimating Algorithm Based on FFT and Its Application to DS-CDMA Receiver
  • ZHAI Ming-yue, LIU Yuan-an, YU Ping
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 79-83.
  • Abstract ( 257 )     HTML     　　
  • After CDMA signals are despreaded, the signal of thedesired user is stronger than others. Based on this property, FFT can be appliedto DOA estimations in array signals. Comparison with MUSIC algorithm is performed, and the results show FFT is applicable in DOA estimations. DOA information can be used in initializing the weights of the adaptive beamforming. Simulationsshow that LMS convergence rate is speeded and the error is greatly reduced.
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  • An Adaptive Modulation Algorithm forMulticarrier DS-CDMA
  • ZHAO Ya-hong, ZHANG Zhong-pei, WU Wei-ling
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 84-88.
  • Abstract ( 208 )     HTML     　　
  • A suboptimal iterative bit allocation method is proposed, which can accomplish the adaptive modulation allocation of B bits on the multicarrier DS-CDMA carrier groups with only B times of iterative allocation process. Computer simulation has demonstrated that with the adaptive modulation, the performance of the multicarrier DS-CDMA system is greatly improved.
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  • A MOE Receiver with Channel Estimation
  • XIAO Hua-wu, TAN Ze-fu, LIU Yuan-an
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 89-92.
  • Abstract ( 223 )     HTML     　　
  • A MOE with channel estimation is discussed. With channel estimation, the performance of MMSE receiver is much improved which is better than all the other algorithms in high BER rate.
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  • Research of WIN-based SIM Interactions Model
  • WANG Yu-long, LIAO Jian-xin
  • Journal of Beijing University of Posts and Telecommunications. 2002, 25(4): 93-100.
  • Abstract ( 234 )     HTML     　　
  • Based on a service logic model defined by WIN protocol, an implementation scheme of interaction among different SIMs is provided. Then a service example is presented for showing the process of inteaction among SIMs.
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