Hong-Wen Zhu

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

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Publications (12)2.02 Total impact

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    ABSTRACT: A novel phase acquisition method of code division multiple access (CDMA) address code is proposed in this paper. Based on the combination of chaotic nonlinear maps and backpropagation neural networks, this new approach can be applied to realize the phase acquisition of a CDMA address code, which plays an important role in wireless mobile communications. Both the theoretical analysis and computer simulation results show that it can increase the detection probability of the received signals compared with the conventional series acquisition method, which can improve the performance of the CDMA receiving system significantly.
    Circuits Systems and Signal Processing 12/2002; 22(1):1-17. · 0.98 Impact Factor
  • Wei Bai, Chen He, Ling-ge Jiang, Hong-wen Zhu
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    ABSTRACT: MIMO-OFDM is one of the promising scheme for achieving high data rate and large system capacity over wireless networks. In this paper, we investigate the blind channel estimation in MIMO-OFDM systems based on the noise subspace method. We exploit the cyclostationarity induced by OFDM with cyclic prefix. The sufficient identifiability conditions were established, and the noise subspace algorithm was developed for MIMO-OFDM channel estimation. The algorithm only requires knowledge of the upper bound on the channel length, it does not impose restrictions on channel zeros and it exhibits low sensitivity to stationary noise. Finally, we demonstrate validity of the algorithm presented in this paper by Monte Carlo simulations.
    Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE; 12/2002
  • Wei Bai, Chen He, Hong-Wen Zhu
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    ABSTRACT: The blind channel estimation problem in orthogonal frequency division multiplexing (OFDM) systems is investigated. A new algorithm called URV decomposition, which serves as an intermediary between QR decomposition and singular value decomposition (SVD), is used to track the space of the received data. URV decomposition has almost the same estimation performance as SVD, but has less computational complexity.
    Signal Processing, 2002 6th International Conference on; 09/2002
  • Lei Fan, Jian-Hua Li, Hong-Wen Zhu
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    ABSTRACT: Yang and Shieh proposed a timestamp-based password authentication scheme. Chan and Cheng proved that it is insecure. In this paper, we will give a further cryptanalysis of the scheme, and give an easier attack on it. Finally, we will propose an improved scheme that can withstand both of the attacks. Compared to other authentication schemes, this improved scheme allows the host to authenticate a user only with his login request. The host need not keep any secret or information of the user.
    Computers & Security. 01/2002;
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    ABSTRACT: A one-dimensional iterative chaotic map with infinite collapses within symmetrical region [-1, O)∪(O, +1] is proposed. The stability of fixed points and that around the singular point are analyzed. Higher Lyapunov exponents of proposed map show stronger chaotic characteristics than some iterative and continuous chaotic models usually used. There exist inverse bifurcation phenomena and special main periodic windows at certain positions shown in the bifurcation diagram, which can explain the generation mechanism of chaos. The chaotic model with good properties can be generated if choosing the parameter of the map properly. Stronger inner pseudorandom characteristics can also be observed through χ<sup>2</sup> test on the supposition of even distribution. This chaotic model may have many advantages in practical use
    IEEE Transactions on Circuits and Systems I Fundamental Theory and Applications 08/2001;
  • Sheng-Hong Li, Hong-Wen Zhu
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    ABSTRACT: This paper proposes an approach to retrieve real harmonics with or without quadratic phase coupling in mixed arbitrarily distributed non-Gaussian and Gaussian ARMA noises. The real observations are first changed into their complex forms by Hilbert transform, then some kind of cumulant is used to identify the AR parameters of the non-Gaussian noise. After filtering the observations with the identified AR parameters, the harmonics are retrieved by cumulant based method. For the approach, simulation shows its performance
    Circuits and Systems, 2001. ISCAS 2001. The 2001 IEEE International Symposium on; 06/2001
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    ABSTRACT: A new spreading sequences phase tracking method utilizing the Lorenz dynamic chaotic synchronization is proposed. It has good performance in withstanding the dynamic Gaussian noise existing in the mobile channel distinctly, and shows lower variance characteristics than “early-late” gate PLL circuit. It also gives attractive advice to the simplification of mobile equipment and the solutions of other tough questions in CDMA mobile communications
    Circuits and Systems, 2001. ISCAS 2001. The 2001 IEEE International Symposium on; 06/2001
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    ABSTRACT: A new approach to synchronisation of Chua's circuit is presented. It effectively combines the interior penalty method of optimisation and chaotic synchronisation. Even under unfavourable, noisy conditions, the approach shows attractive lower variance results compared with conventional chaotic synchronisation in realising the synchronisation of length-limited noisy chaotic signals
    Electronics Letters 04/2001; · 1.04 Impact Factor
  • Sheng-Hong Li, Hong-Wen Zhu, Jian-hua Li
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    ABSTRACT: The problem of modeling MPEG-1 VBR video traffic is studied. Based on the analysis of their statistical characteristics, this paper presents a new direct frame-layered traffic model for VBR video traffic using the MPEG-1 scheme and group of pictures (GOP) pattern “IBBPBBPBBPBB”. The model can reflect the first- and second-order frame-layered statistical characteristics of this video traffic well simultaneously. Simulation results also show that the model can capture the behavior of this traffic in a queue effectively
    Wireless Communications, 2001. (SPAWC '01). 2001 IEEE Third Workshop on Signal Processing Advances in; 02/2001
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    ABSTRACT: A novel radio resource management approach composed of the space division multiple access (SDMA) strategy and the dynamic resource assignment for the stratospheric platform (SPF) communication system is proposed. Since the whole channel resource is shared with each beam of the digital beamforming (DBF) multibeam onboard antenna, it realizes our objective by making good use of the spectrum resource to meet the increasing demand of mobile communications and broadband fixed wireless access (FWA) services within the limited spectrum. Computer simulation result illustrate that the communication capacity of an SPF communication system increases significantly
    Communications, 2001. ICC 2001. IEEE International Conference on; 02/2001
  • Sheng-Hong Li, Hong-Wen Zhu
    International Symposium on Circuits and Systems (ISCAS 2001), 6-9 May 2001, Sydney, Australia; 01/2001
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    ABSTRACT: A chaotic map model with infinite collapses in the finite region is proposed in this paper. The scheme of generating chaotic signals from this model is analyzed. Lyapunov exponents of the map calculated indicates that it has good properties of chaos. The CDMA spreading sequences produced by the model can achieve better autocorrelation and crosscorrelation characteristics than Gold sequences usually used
    TENCON 2000. Proceedings; 02/2000