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    25 November 2005, Volume 26 Issue 11
    academic paper
    Study of a new fast adaptive filtering algorithm
    ANGZhen-li W,HANGXiong-wei Z,ANGJi-bin Y,HENGong C
    2005, 26(11):  1-6.  doi:1000-436X(2005)11-0001-06
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    A new fast adaptive filtering algorithm was presented by using the correlations between the signal's former and latter sampling times. The proof of the new algorithm was also presented, which showed that its optimal weight vector was the solution of generalized Wiener equation. The new algorithm was of simple structure, fast convergence, less stable maladjustment. It had the ability of dealing with many signals, including noncorrelation signal and strong correlation signal. However, its computational complexity was comparable to that of NLMS algorithm. Simulation results show that for noncorrelation signal, the stable maladjustment of the proposed algorithm is less than that of VS-NLMS algorithm, and its convergence is comparable to that of the algorithm proposed in reference but faster than that of L.E-LMS algorithm. For high correlation signal, its performance is superior to those of NLMS algorithm and DCR-LMS algorithm.

    Study of hybrid optical burst switching networks
    ENGPeng P,ANYu-yan P,ANGJun-feng W,INJin-tong L
    2005, 26(11):  7-11.  doi:1000-436X(2005)11-0007-05
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    The hybrid optical burst switching (HOBS) was proposed, and investigate the HOBS based a ring topology with numerical simulation. Results indicate that the packet lost ratio in HOBS is much less than that in OBS, and its performance depends on some parameters such as the packet proportion, the electronic buffer size and the processing speed in node.

    Multiuser diversity scheme with partial feedback of channel metric on common uplink channel and its performance
    ONGMing G,IULing Q,HUJin-kang Z
    2005, 26(11):  12-17.  doi:1000-436X(2005)11-0012-06
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    By investigating the throughput performance of multiuser diversity system with random beamforming, a multiuser diversity scheme with partial feedback of channel metric on common uplink channel were proposed. Performance analysis proves that with proper threshold, partial feedback of channel quality can pay much less for uplink feedback with little decrease of system throughput, which means that the system will accommodate more user within given bandwidth.

    Study of a new packet marking scheme for DDoS attack source traceback
    IJin-ming L,ANGRu-chuan W
    2005, 26(11):  18-23.  doi:1000-436X(2005)11-0018-06
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    On the base of study of packet marking scheme's convergence, a new method of choosing marking probability had been put forward to get the optimization of convergence. Meanwhile, a new safe verified packet marking scheme had been brought forward to countermeasure the information forged by routes which had been controlled by an attacker, and this forged information should disturb the arithmetic of rebuilding the attacking path. Lastly, this scheme's performances were emulated and tested and the result shows that the performances are better than other packet marking schemes.

    Spreading and coding for anti-interference in UWB system
    UChen X,HANGShi-bing Z
    2005, 26(11):  24-29.  doi:1000-436(2005)11-0024-06
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    Spreading every transmitted bit over each sub-band and interleaving the spread signals over all of the sub-bands would provide the robustness to narrow-band interference in the ultra-wide band (UWB) system based on orthogonal frequency-division multiplexing (OFDM). Simulation results show that the system has evident robustness against narrow-band interference and would improve the performance about 5dB in SIR or 1~2 order in BER.

    Analysis of load balance performance of multipath in wireless ad hoc networks
    ANGHui W,UNeng-hai Y
    2005, 26(11):  30-37.  doi:1000-436X(2005)11-0030-08
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    A novel analysis model for computing the load of wireless ad hoc network that uses multipath routing was proposed. This model took the number of paths, the way of route selecting and the density of the network nodes into account and could analyse or compute the load in different network conditions. The result of the simulation fits the theory perfectly and give the conclusion that using multipath routing alone in wireless ad hoc network can not balance the load of network effectively. This is not the same as we always accept (using multipath routing in wireless ad hoc network can balance the load of network and increase throughput just as in the normal network).

    Forward secure proxy signature scheme
    ANGXiao-ming W,HENHuo-yan C,UFang-wei F
    2005, 26(11):  38-41.  doi:1000-436X(2005)11-0038-05
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    A forward secure proxy signature scheme was proposed combining the concept of forward security with proxy signature. This means even if an adversary has gotten the current proxy signers' key, It could not forge proxy signature pertaining to the past, that is, previous generated proxy signatures remain still valid. Furthermore, the scheme can control the proxy signature time of the proxy singer.

    Intra-prediction mode decision based on video temporal and spatial correlation
    AISheng-kui D,ULi Y,HUGuang-xi Z,IUWen-yu L
    2005, 26(11):  43-48.  doi:1000-436X(2005)11-0043-06
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    An intra-prediction mode-decision method was proposed. Based on the inherent spatial correlation within a single frame and temporal correlation between successive frames, part of intra-prediction modes were chosen to determine the best prediction mode for image block, which resulted in directly reducing the computational complexity and maintaining high coding efficiency. In addition, a complexity-scalable technique was presented to control the complexity of intra prediction, by which the video coder was matched to the limited computational resource of communication equipments. The proposed methods are verified in AVS-M software platform.

    Novel Rake receiver structure for ultra wideband system based on antenna diversity
    ILi-na Q,ANZong-liang G,HUHong-bo Z
    2005, 26(11):  49-54.  doi:1000-436X(2005)11-0049-06
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    A novel receiver structure for TH-UWB wireless communication system was proposed. The improved receiver, combining the antenna diversity with Rake receiver, could enhance the ability to suppress the multi-user interference and multipath fading. Theoretic analysis and simulation results show that the proposed receiver can achieve better performance than the conventional Rake receiver.

    Linear discriminant analysis in network traffic modeling
    HANGBing-yi Z,IANYu-lan B,HANGHong-ke Z,UNYa-min S
    2005, 26(11):  55-61.  doi:1000-436X(2005)11-0055-07
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    It was not easy to give an accurate judgment of whether the traffic model fitting the actual traffic. The common method was to compare the Hurst parameter, data histogram and autocorrelation function. The method of comparing Hurst parameter could't give exact results and judgment. The method of comparing data histogram and autocorrelation could only give a qualitative judgment. Based on linear discriminant analysis a arithmetic was proposed. Utilizing this arithmetic the data in the sets of different traffic model and in NS was analyzed. The results are accurate. Compared with traditional method this arithmetic is useful and can conveniently give an accurate judgment for complex network traffic trace.

    New short interleaver design for Turbo codes
    IUWen-ming L,HUGuang-xi Z,EYe-jun H
    2005, 26(11):  62-67.  doi:1000-436X(2005)11-0062-06
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    The effect of the self interleaving distance and correlative interleaving distance of the interleaver on the decoding performance was investigated. The functions of interleaving distance were put forward and a design rule of interleaver was presented. Based on the analysis, a new interleaver generated by using a linear recursion was proposed. Simulation results show that they exhibit good bit error performance.

    Technical Report
    Hybrid architecture based on fuzzy classifier and multiplayer feed-forward neural network for speaker identification
    HANGLing-hua Z,ANGZhen Y,HENGBao-yu Z
    2005, 26(11):  68-75.  doi:1000-436X(2005)11-0068-08
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    A novel method for speaker identification was proposed which was based on a fuzzy classifier with hyperellipsoidal regions. First, the training data for each class were divided into several clusters. Then, for each cluster, a fuzzy rule with a hyperellipsoidal region was defined around a cluster center. The evaluation experiments had been conducted to compare the fuzzy hyperellipsoidal classifier with the HMM. It was found that the former classifier can achieve a comparable speaker identification performance to the latter with higher clustering speed. Further research showed that both fuzzy hyperellipsoidal classifier and the HMM worsened the recognition ability when the test data contained noise. To overcome this problem, a hybrid architecture based on fuzzy classifier and multilayer feed-forward neural network (MLFNN) was developed for speaker recognition. The experimental results showed that the new method can achieve a much better identification performance and robustness to the additive noise.

    Multi-path backup optimized power algorithm for wideband networks
    UYu-bin X,ANWei T
    2005, 26(11):  76-81.  doi:1000-436X(2005)11-0076-06
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    A multi-path backup optimized power algorithm was presented for wideband network, which exerted multi-path backup routing and reduced the total transmission power. This algorithm was suitable for structure-changed mobile ad hoc network and power-restricted UWB network. The simulation result shows that the new algorithm can increase the throughput of network and improve delay and overhead.

    Design of a multistage anti-jam GPS receiver
    IMin-min D,HANGEr-yang Z
    2005, 26(11):  82-86.  doi:1000-436X(2005)11-0082-05
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    Since the anti-jam capability of joint space-time processing used in GPS depended on the number of antenna elements, a multistage anti-jam GPS receiver was proposed. It was of low complexity compared to the joint space-time processing receiver with the same anti-jam capability. Finally the simulation results presented prove it is of advantage in decreasing computation complexity and improve anti-jam capability.

    Short essay
    Improved ABR flow control algorithm
    IUZhi-xin L,UANXin-ping G,ONGCheng-nian L
    2005, 26(11):  87-92.  doi:1000-436X(2005)11-0087-06
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    To improve the performance of traffic management of ATM networks, an improved ABR flow control algorithm was proposed based on discrete model. The effect of the delay elements was considered further with the structure of follow-up control system. The method of choosing parameters, which can guarantee the stability of closed loop time-delay system, was given. The method can avoid the congestion, allocate the available bandwidth fairly and improve the quality of service. The simulation results show that the theory is correct and practical.

    Improved non-Rake receiver based on two dimensional spread spectrum for WCDMA systems
    ANGYou-xi T,HAOShi-hai S,ANWen-sheng P,IShao-qian L
    2005, 26(11):  93-99.  doi:1000-436X(2005)11-0093-07
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    A direct sequence spread spectrum receiver based on two dimensional spread spectrum for WCDMA systems was proposed. Unlike the conventional Rake receiver, the proposed receiver is motivated by idea of the transform domain design and makes full use of the multipath signals. And compared with the conventional Rake receiver, the proposed receiver is presented by computer simulations to support its bit error rate (BER) performance when it is difficult for the Rake receiver to distinguish each path accurately.

    Performance evaluation of AQM schemes: a comparative study
    IQi-jin1 J,ONGYong-qiang D
    2005, 26(11):  100-105.  doi:1000-436X(2005)11-0100-06
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    A taxonomy of AQM schemes was presented, and typical AQM algorithms were compared in terms of a number of performance metrics under different traffic and network topology conditions based on the NS2 simulation platform. The main results of this paper include: ARED performs better than other algorithms; PI controller and REM responses slowly to dynamic traffic; AVQ without ECN support and REM can maintain lower queue length but at the cost of lower link utilization and higher packet loss rate; The performance of AVQ is significantly improved combined with ECN; Most AQM algorithm perform better in multiple bottleneck link topology.

    Research on intrusion detection system based on two-level algorithm
    INBo-ping Q,HOUXian-wei Z,ONGCun-yi S
    2005, 26(11):  106-110.  doi:1000-436X(2005)11-0106-06
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    To the limitation of current intrusion detection models, an idea of formulating an intrusion detection model system (TAIDS) based on the GMTH Two-level algorithm was presented. With the joint of two-level algorithm and GMDH multi-stage iterate method, TAIDS would construct models simultaneously with data from different time range, which could enlarge the time range of the detected intrusive behavior. Through the analysis of the target system, relations between influential factors in intrusion were searched and an optimal model was built, which would decrease the false retrieval and fallout ratio efficiently. System framework and model algorithm were given also. This model system is proved to be effective from the comparison of emulating experiments on Snort and NIDES detection system.

    Maximum Doppler frequency estimation algorithm for OFDM systems
    AIWei C,HUGuang-xi1 Z,ZHANGQing-chun ,,ILi L
    2005, 26(11):  112-116.  doi:1000-436X(2005)11-0112-05
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    Based on the analysis of some algorithms for the Doppler frequency estimation, a new method for acquiring the maximum Doppler frequency information was proposed. This new algorithm was based on the periodogram theory. It used the received pilots and did not need the channel estimators. Simulations have proved that this algorithm performs well both in single- and multi-path channel. It is suitable for OFDM communication systems.

    Academic communication
    VLSI architecture design of motion compensation for MPEG-4
    IULong L,ANChong-zhao H,ANGZhan-hui W
    2005, 26(11):  117-124.  doi:1000-436X(2005)11-0117-08
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    In the light of complex control, high throughput and difficult implementation of motion compensation of MPEG-4 decoding, a motion compensation (MC) circuit solving the timing and I/O of decoding was presented for MPEG-4.The VLSI architecture and implementation in terms of VHDL were designed in the Xilinx ISE6.1i environment and some simulations were carried out in tools of electronic design automation (EDA). The experimental results show that the VLSI processor designed can perform correct logic functions and can achieve a real-time coding for MPEG-4 Core Profile and Level 2.

    Analysis on IP-based density of Internet
    UYe X,HAOHai Z,UWei-ji S,HANGWen-bo Z,HANGXin Z,ANGZu-wei W
    2005, 26(11):  125-131.  doi:1000-436X(2005)11-0125-07
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    Physical properties of Internet were discussed. Based on analysis of giant data, IP-based density, a physical property parameter of Internet spacial validity, was firstly formally defined. Then a fitting model of density was generated by GA. What's more, the fitting model was evaluated in several ways such as quantitative and qualitative analysis, fitting and forecast correctness of the model. Condition of Internet in the future, especially in Aug. 2008 when Olympic Games will be held in Beijing, was forecasted by the model and a result was yielded that Internet in August 2008 will be highly available.

    Research on unequal error protection of irregular LDPC codes
    APi-ming M,UANDong-feng Y,ANGXiu-mei Y
    2005, 26(11):  132-136.  doi:1000-436X(2005)11-0132-05
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    An irregular low-density parity-check (LDPC) code with unequal error protection (UEP) property was proposed. A weight-increasing parity-check (WIPC) matrix was constructed. With systematic encoding, the “important information bits” in information sequence could successfully be mapped to the “elite bits” of an irregular LDPC code. Simulation results over AWGN and Rayleigh fading channels show that LDPC codes from WIPC matrix can achieve better UEP performance than conventional randomly constructed irregular LDPC codes.

    User authentication scheme based on the ElGamal signature for mobile communication system
    IWei-ke L,IFang-wei L
    2005, 26(11):  137-139.  doi:1000-436X(2005)11-0137-03
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    An efficient user authentication protocol was presented for a digital mobile communication system based on the ElGamal signature. Compared with the original scheme, the new scheme had improved the security performance of the network center as well as reduced the cost calculation of the user through improvements made in the authentication process. The analysis of the new scheme shows that the modified scheme is of higher security and lower calculative complexity, which satisfies the requirements of mobile communication.

Copyright Information
Authorized by: China Association for Science and Technology
Sponsored by: China Institute of Communications
Editor-in-Chief: Zhang Ping
Associate Editor-in-Chief:
Zhang Yanchuan, Ma Jianfeng, Yang Zhen, Shen Lianfeng, Tao Xiaofeng, Liu Hualu
Editorial Director: Wu Nada, Zhao Li
Address: F2, Beiyang Chenguang Building, Shunbatiao No.1 Courtyard, Fengtai District, Beijing, China
Post: 100079
Tel: 010-53933889、53878169、
53859522、010-53878236
Email: xuebao@ptpress.com.cn
Email: txxb@bjxintong.com.cn
ISSN 1000-436X
CN 11-2102/TN
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