Dunmin Zheng

University of Florida, Gainesville, Florida, United States

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Publications (8)13.77 Total impact

  • Jian Li, Dunmin Zheng
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    ABSTRACT: This correspondence presents a RELAX (RELAXation-based) algorithm for angle, polarization, and waveform estimation of completely polarized narrowband electromagnetic plane waves arriving at a uniform linear co-centered orthogonal loop and dipole (COLD) array. We use numerical examples to demonstrate the performance of the RELAX algorithm for parameter estimation with the COLD array and compare it with the performance of the MODE (Method of Direction Estimation) algorithm. We show that this RELAX algorithm can outperform MODE and yet be computationally faster than MODE.
    Circuits Systems and Signal Processing 06/1998; 17(4):471-481. · 0.98 Impact Factor
  • Jian Li, Petre Stoica, Dunmin Zheng
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    ABSTRACT: In this paper, we describe how the computationally efficientone-dimensional MODE (1D-MODE) algorithm can be used to estimatethe frequencies of two-dimensional complex sinusoids. We showthat the 1D-MODE algorithm is computationally more efficientthan the asymptotically statistically efficient 2D-MODE algorithm,especially when the numbers of spatial measurements are large.Interestingly enough, we prove that the 1D-MODE algorithm isasymptotically statistically efficient for high signal-to-noiseratio. We also show that although 1D-MODE is no longer statisticallyefficient when the number of temporal snapshots is large, theperformance of 1D-MODE can still be very close to that of the2D-MODE under mild conditions. Numerical examples comparing theperformances of the 1D-MODE and 2D-MODE algorithms are alsopresented.
    Multidimensional Systems and Signal Processing 09/1997; 8(4):449-468. · 0.86 Impact Factor
  • Jian Li, Dunmin Zheng, P. Stoica
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    ABSTRACT: Describes how the RELAX algorithm, recently proposed for temporal spectral analysis, can be extended to the spatial problem of angle and waveform estimation for both narrowband and wideband plane waves arriving at a uniform linear array (ULA). Both numerical and experimental examples are used to demonstrate the performance of the RELAX algorithm and compare the performance of RELAX with that of other well-known algorithms including ESPRIT with forward/backward spatial smoothing, MODE/WSF, and AP/ANPA for narrowband signals, and CSM-ESPRIT for wideband signals.
    IEEE Transactions on Aerospace and Electronic Systems 08/1997; · 1.30 Impact Factor
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    Dunmin Zheng, Jian Li, P. Stoica
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    ABSTRACT: This paper describes how the computationally efficient one-dimensional MODE (1D-MODE) algorithm can be used to estimate the frequencies of two-dimensional complex sinusoids. We show that the 1D-MODE algorithm is computationally more efficient than the asymptotically statistically efficient 2D-MODE algorithm, especially when the numbers of spatial measurements are large. We find that the 1D-MODE algorithm is asymptotically statistically efficient for high signal-to-noise ratio. We also show that although the 1D-MODE is no longer statistically efficient when the number of temporal snapshots is large, the performance of the 1D-MODE can still be very close to that of the 2D-MODE under mild conditions. Numerical examples comparing the performance of the 1D-MODE and 2D-MODE algorithms are also presented
    Acoustics, Speech, and Signal Processing, 1997. ICASSP-97., 1997 IEEE International Conference on; 05/1997 · 4.63 Impact Factor
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    Dunmin Zheng, Jian Li, S.L. Miller, E.G. Strom
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    ABSTRACT: We present an efficient algorithm for estimating the code timing of a known training sequence in an asynchronous direct-sequence code division multiple access (DS-CDMA) system. The algorithm is a large sample maximum likelihood (LSML) estimator that is derived by modeling the known training sequence as the desired signal and all other signals including the interfering signals and thermal noise as unknown colored Gaussian noise that is uncorrelated with the desired signal. The LSML estimator is shown to be robust against the near-far problem and is also compared with several other code timing estimators via numerical examples. It is found that the LSML approach can offer noticeable performance improvement, especially when the loading of the system is heavy
    IEEE Transactions on Signal Processing 02/1997; · 2.81 Impact Factor
  • Dunmin Zheng, Jian Li, S.L. Miller
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    ABSTRACT: In this paper, we present an efficient algorithm for estimating the propagation delay of a known training sequence in an asynchronous direct-sequence code division multiple access (DS-CDMA) system. The algorithm is a large sample maximum likelihood (LSML) estimator that is derived by modeling the known training sequence as the desired signal and all other signals including the interfering signals and thermal noise as unknown colored Gaussian noise that are uncorrelated with the desired signal. LSML is asymptotically statistically efficient as the length of the training sequence goes to infinity. We shall show that LSML is robust against the near-far problem. The performance of the LSML estimator is compared with that of the MUSIC estimator via numerical examples and is shown to be better than that of the latter method in the sense of having lower root-mean-squared errors, lower computational complexity, and tolerating more users
    Acoustics, Speech, and Signal Processing, 1996. ICASSP-96. Conference Proceedings., 1996 IEEE International Conference on; 06/1996
  • Jian Li, P. Stoica, Dunmin Zheng
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    ABSTRACT: This paper considers angle and polarization estimation by means of a cocentered orthogonal loop and dipole (COLD) array. We show that by using the COLD array, the performance of both angle and polarization estimation can be greatly improved, as compared to using a crossed dipole array. We present an asymptotically statistically efficient method of direction estimation (MODE) algorithm that can be used with the COLD array for both angle and polarization estimation of correlated (including coherent) or uncorrelated incident signals. Numerical examples are given to show the better estimation performance of the MODE algorithm than that of the multiple signal classification (MUSIC) and the noise subspace-fitting (NSF) algorithms
    IEEE Transactions on Antennas and Propagation 05/1996; · 2.33 Impact Factor
  • Jian Li, Petre Stoica, Dunmin Zheng
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    ABSTRACT: This paper presents a computationally efficient eigenstructure-based 2D-MODE algorithm for two-dimensional frequency estimation. We derive the theoretical performance of the 2D-MODE estimator and show that it is asymptotically statistically efficient under either the assumption that the number of temporal snapshots is large or the signal-to-noise ratio is high. Numerical examples showing the performance of this algorithm and comparing it with the computationally efficient subspace rotation algorithms are also given. We show that the statistical performance of the 2D-MODE algorithm is better than that of the subspace rotation methods. The amount of computations required by the former is no more than a few times of that needed by the latter for either small numbers of spatial measurements or a single temporal snapshot, which are the cases of interest herein.
    Multidimensional Systems and Signal Processing 03/1996; 7(2):151-178. · 0.86 Impact Factor