For the purpose of improving the DOA estimation performance, we propose a new simplified temporal-spatial maximum likelihood algorithm. Instead of using the discrete Fourier transform(DFT) filters, the proposed algori...
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ISBN:
(纸本)0780374886
For the purpose of improving the DOA estimation performance, we propose a new simplified temporal-spatial maximum likelihood algorithm. Instead of using the discrete Fourier transform(DFT) filters, the proposed algorithm uses the special Doppler filters to process the received data according to signal's Doppler frequency. The processed data are then used by the maximum likelihood algorithm to estimate DOA. Because the special Doppler filters can greatly reduce the influences between signals, the proposed algorithm works significantly better than the simplified temporal-spatial maximum likelihood algorithm. Computer simulation results are presented and demonstrate the merits of the proposed algorithm.
In this paper, a novel wavelet packet division multiplexing (WPDM) system based on Fractionally Spaced Equalizers (FSE) and maximumlikelihood (ML) algorithm is studied for multipath fading channels. New discrete wave...
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ISBN:
(纸本)0780391527
In this paper, a novel wavelet packet division multiplexing (WPDM) system based on Fractionally Spaced Equalizers (FSE) and maximumlikelihood (ML) algorithm is studied for multipath fading channels. New discrete wavelet packet transform structure based on FSE, which uses Least Mean Square (LMS) algorithm and NIL detecting algorithm, are the two novel aspects of the presented system It is demonstrated by simulation results that the FSE method is superior to the Zero-Forcing equalizers (ZFE) method in performance and the FSE-WPDM scheme can provide greater immunity to multipath fading channels and AWGN than the FSE-OFDM scheme.
An improved parallel interference cancellation (PIC) detector based on conditional likelihood function is presented. The improved PIC benefits from an additional correcting module after the last stage, where the maxim...
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ISBN:
(纸本)0780376633
An improved parallel interference cancellation (PIC) detector based on conditional likelihood function is presented. The improved PIC benefits from an additional correcting module after the last stage, where the maximum likelihood algorithm using only the conditional likelihood function, which is calculated from the information of the tentative decisions, is employed. Analysis and simulation show that the new algorithm can improve the bit error rate (BER) performance of PIC with much lower computation complexity than optimum detector.
We consider the problem of estimating directions of arrival (DOAs) of multiple sources observed on the background of nonuniform white noise with an arbitrary diagonal covariance matrix. A new deterministic maximum lik...
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We consider the problem of estimating directions of arrival (DOAs) of multiple sources observed on the background of nonuniform white noise with an arbitrary diagonal covariance matrix. A new deterministic maximumlikelihood (ML) DOA estimator is derived. Its implementation is based on an iterative procedure which includes a stepwise concentration of the log-likelihood (LL) function with respect to the signal and noise nuisance parameters and requires only a few iterations to converge. New closed-form expressions for the deterministic and stochastic direction estimation Cramer-Rao bounds (CRBs) are derived for the considered nonuniform model. Our expressions can be viewed as an extension of the well-known results by Stoica and Nehorai and Weiss and Friedlander to a more general noise model than the commonly used uniform one. In addition, these expressions extend the recent results by Matveyev et al. to the multiple source case. Comparisons with the above-mentioned earlier results help to discover several interesting properties of DOA estimation in the nonuniform noise case, To compare the estimation performance of the proposed ML, technique with the results of our CRB analysis and with the performance of conventional "uniform" ME, simulation results are presented. Additionally, we test our technique using experimental seismic array data. Our simulations and experimental results both validate essential performance improvements achieved by means of the approach proposed.
A maximun likelihoodalgorithm for code timing estimation of DS-CDMA signals in slow fading multipath channels is presented. As an extension to a recently presented method, it decomposes a multidimensional minimisatio...
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A maximun likelihoodalgorithm for code timing estimation of DS-CDMA signals in slow fading multipath channels is presented. As an extension to a recently presented method, it decomposes a multidimensional minimisation problem into a smaller problem. Simulation results show that the proposed estimator is near-far resistant.
Conventional along-track interferometric (ATI) synthetic aperture radar (SAR) systems derive the ocean surface Velocity from an estimate of the phase difference between the SAR echoes received from two displaced phase...
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Conventional along-track interferometric (ATI) synthetic aperture radar (SAR) systems derive the ocean surface Velocity from an estimate of the phase difference between the SAR echoes received from two displaced phase centres with a single time-lag. A maximum likelihood algorithm is proposed to process multichannel SAR data from an array of phase centres with multiple time-lags. The new technique provides better estimation accuracy than the conventional technique, unambiguous velocity retrieval, and extended operational capability.
A maximum likelihood algorithm to detect moving targets in space-time electro-optic data is derived using a model of temporally stationary and spatially nonstationary clutter statistics. Performance is evaluated in te...
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A maximum likelihood algorithm to detect moving targets in space-time electro-optic data is derived using a model of temporally stationary and spatially nonstationary clutter statistics. Performance is evaluated in terms of the probabilities of false alarm and detection. This algorithm is applied to a variety of image sequences: visible band and infrared (IR) sensors, with terrestrial and celestial clutter backgrounds. Comparison of theoretically predicted and experimentally derived statistics shows excellent agreement, validating the model and theoretical predictions.
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