共查询到20条相似文献,搜索用时 15 毫秒
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《Communications Letters, IEEE》2002,6(5):205-207
A new non-data-aided feedforward symbol timing estimator is proposed, which can apply to two samples per symbol. Numerical results show the proposed estimator is approximately unbiased. Computational complexity of the new estimator is even simpler than conventional estimators with two samples per symbol. Estimation accuracy of the new estimator is similar to that of the conventional estimator with four samples per symbol presented by Oerder and Meyr in 1988, which is the simplest among the estimators using four samples per symbol. While some conventional estimators have better estimation accuracy than the proposed, this estimator has an attractive advantage over the formers from an implementation point of view 相似文献
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A low complexity symbol timing estimator for MIMO systems using two samples per symbol 总被引:1,自引:0,他引:1
《Communications Letters, IEEE》2006,10(7):525-527
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Wei-Ping Zhu Yupeng Yan Ahmad M.O. Swamy M.N.S. 《IEEE transactions on circuits and systems. I, Regular papers》2005,52(11):2490-2500
In this paper, a new feedforward symbol timing recovery technique using timing estimation followed by interpolation is presented for digital receivers with two samples/symbol or higher sampling rate. A few timing estimation algorithms are proposed to estimate the timing offset accurately. The basic algorithm uses only the in-phase (I) or quadrature (Q) signal for timing detection, which applies to a BPSK communication system. It is shown that the basic algorithm, when applied in quadrature modulation systems where both I and Q signals are available, can be modified slightly to yield an improved estimation precision. The mean and variance of the resulting timing estimate are analyzed and simulated, supporting a satisfactory estimation performance. It is also shown that by applying a postprocessing scheme, such as the Kalman filter, the variance can be further reduced, resulting in a smoothed timing estimate. Some of the issues concerning the implementation of the proposed technique are also addressed. 相似文献
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A low complexity feedforward symbol-timing estimator based on the conditional maximum-likelihood principle is proposed. An approximation is applied to the Fourier series expansion of the conditional maximum-likelihood function such that implementation complexity is greatly reduced. It is shown that the proposed estimator can be viewed as a generalization of the well-known square nonlinearity estimator proposed by Oerder and Meyr in 1988. Simulation results show that the performance of the proposed estimator is very close to the conditional Cramer-Rao bound and is better than that of the square nonlinearity estimator. 相似文献
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In this letter, all the previously proposed digital blind feedforward symbol timing estimators employing second-order statistics are casted into a unified framework. The finite sample mean-square error (MSE) expression for this class of estimators is established. Simulation results are also presented to corroborate the analytical results. It is found that the feedforward conditional maximum likelihood (CML) estimator and the square law nonlinearity (SLN) estimator with a properly designed prefilter perform the best and their performances coincide with the asymptotic conditional Cramer-Rao bound (CCRB), which is the performance lower bound for the class of estimators under consideration. 相似文献
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The authors deal with two types of feedforward carrier-independent non-decision-aided (NDA) symbol synchronizers for PAM, which are based upon the maximum-likelihood criterion. Their timing error variances are compared, for two important classes of signal constellations 相似文献
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A statistical analysis of a decision-directed symbol timing algorithm for phase shift keyed modems is presented. The timing detector uses only one sample per symbol period and is suitable for high speed modems which employ discrete-time synchronization methods. Expressions for the timing detector's mean value and variance, as a function of timing offset, are derived and compared to simulation results. The analysis includes the effects of decision errors which occur at low signal-to-noise ratios and eventually limit the useful operating range of the decision-directed methods. A modification is described so that the need for prior phase recovery is avoided. These algorithms are compared to a popular two-sample-per-symbol nondecision-directed timing detector. A method of examining the relative performance of the various algorithms is presented and results are given for a range of signal-to-noise ratios and channel bandwidths 相似文献
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In this paper we have proposed a method for the determination of prefixed sample size (m) used in the estimation of population proportion proposed by Haldane (1) for specified permissible error with a given confidence coefficient and an improved estimator for population proportion using inverse sampling scheme. 相似文献
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This paper presents adaptive algorithms for estimating the location of a mobile terminal (MT) based on radio propagation modeling
(RPM), Kalman filtering (KF), and radio-frequency identification (RFID) assisting for indoor wireless local area networks
(WLANs). The location of the MT of the extended KF positioning algorithm is extracted from the constant-speed trajectory and
the radio propagation model. The observation information of the KF tracker is extracted from the empirical and RPM positioning
methods. Specifically, a sensor-assisted method employs an RFID system to adapt the sequential selection cluster algorithm.
As compared with the empirical method, not only can the RPM algorithm reduce the number of training data points and perform
on-line calibration in the signal space, but the RPM and KF algorithms can alleviate the problem of aliasing. In addition,
the KF tracker with the RFID-assisted scheme can calibrate the location estimation and improve the corner effect. Experimental
results demonstrate that the proposed location-tracking algorithm using KF with the RFID-assisted scheme can achieve a high
degree of location accuracy (i.e., more than 90% of the estimated positions have error distances of less than 2.1 m). 相似文献
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Abdelfettah Meziane Bentahar Meziane Thierry Chonavel Abdeldjalil Aïssa-El-Bey Adel Belouchrani 《电信纪事》2018,73(11-12):711-717
In this paper, we propose analytical formulas that involve second-order statistics for separating two signals. The method utilizes source decorrelation and correlation function diversity. In particular, the proposed SOBAS (second-order blind analytical separation) algorithm differs from the ASOBI (analytical second-order blind identification) algorithm in that it does not require prior knowledge or estimation of the noise variance. Computer simulations demonstrate the effectiveness of the proposed method. 相似文献
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An approximate maximum likelihood estimator for SNR jointly using pilot and data symbols 总被引:2,自引:0,他引:2
A novel maximum likelihood-based estimator for signal-to-noise ratio (SNR) is derived. Previous SNR estimators are mainly based on using either the pilot symbols or the data symbols. However, in a practical communication system, a frame usually consists of both pilot and data symbols. In this work, a new SNR estimator that uses all available symbols (pilot and data) in a frame is developed for binary phase shift keying signals. The performance of this estimator is examined. Numerical results are presented to show the potential improvement obtained by using this new estimator. 相似文献
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This paper proposes a blind image deconvolution method which consists of two sequential phases, i.e., blur kernel estimation and image restoration. In the first phase, we adopt the L0-norm of image gradients and total variation (TV) to regularize the latent image and blur kernel, respectively. Then we design an alternating optimization algorithm which jointly incorporates the estimation of intermediately restored image, blur kernel and regularization parameters into account. In the second phase, we propose to take the mixture of L0-norm of image gradients and TV to regularize the latent image, and design an efficient non-blind deconvolution algorithm to achieve the restored image. Experimental results on both a benchmark image dataset and real-world blurred images show that the proposed method can effectively restore image details while suppress noise and ringing artifacts, the result is of high quality which is competitive with some state of the art methods. 相似文献
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Symbol timing synchronisation (STSYNC) based on maximum likelihood estimation and a receiver configuration in which each branch independently estimates optimum STSYNC timing are proposed to improve delay spread immunity for I6 QAM/TDMA diversity receivers. Computer simulation confirms that the proposed STSYNC and receiver configuration can improve delay spread immunity by approximately 30%.<> 相似文献
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An alternative degradation reliability modeling approach using maximum likelihood estimation 总被引:5,自引:0,他引:5
An alternative degradation reliability modeling approach is presented in this paper. This approach extends the graphical approach used by several authors by considering the natural ordering of performance degradation data using a truncated Weibull distribution. Maximum Likelihood Estimation is used to provide a one-step method to estimate the model's parameters. A closed form expression of the likelihood function is derived for a two-parameter truncated Weibull distribution with time-independent shape parameter. A semi-numerical method is presented for the truncated Weibull distribution with a time-dependent shape parameter. Numerical studies of generated data suggest that the proposed approach provides reasonable estimates even for small sample sizes. The analysis of fatigue data shows that the proposed approach yields a good match of the crack length mean value curve obtained using the path curve approach and better results than those obtained using the graphical approach. 相似文献