Hua Jingyu

An Adaptive Doppler Shift Estimator in Mobile Communication Systems

In this paper, an adaptive Doppler shift estimator based on the square envelope autocorrelation function of the mobile propagation channel is proposed. Furthermore, the proposed estimator exploits the iterative minimum finding procedure to reduce the effect of additive noise. Both the theoretical analysis and the experiments are provided to show that the proposed method yields fairly good signal-to-noise ratio (SNR) insensitive performance in a wide range of velocities and SNRs

An improved method for Doppler shift estimation in CP-SCBT Mobile Communication Systems

In this paper, the Doppler shift of the time-varying multi-path channel is estimated by calculating the expectation of the ACF (auto-correlation function) of the channel coefficient estimates on the effective fingers. Furthermore we analyze the estimation bias and propose an improved estimation method based on SNR (signal-to-noise ratio) estimation to obtain the high estimation accuracy in wide ranges of velocities and SNRs.

Optimal time and bandwidth allocation based on Nash bargaining solution for cooperative cognitive systems

In this paper, we propose a cooperative spectrum sharing strategy based on the Nash bargaining solution. Specifically, the primary system leases a fraction of its transmission time to the secondary system in exchange for cooperation to improve its transmission performance. To gain access to the spectrum of the primary system, the secondary system needs to split a fraction of its transmission bandwidth to help to forward the primary signal. As a reward, the secondary system can use the remaining bandwidth to transmit its own signal. We find a unique solution for this time and bandwidth allocation using the Nash bargaining solution. Simulation results demonstrate that the performance of the primary and secondary systems can both be improved by the proposed spectrum sharing strategy.

WLCp1-17: A SNR Independent Doppler Shift Estimator Based on Iterative Process in Mobile Communication Systems

In this paper, we propose a Doppler shift estimator based on the autocorrelation function (ACF) of the time-varying channel. In order to eliminate the effect of additive noise, we analyze the conditions for the estimator independent of the signal- to-noise ratio (SNR) and implement the conditions with a simple iterative process named as adaptive lag. The proposed method achieves good SNR-independent performance in wide range of velocities and SNRs.

Evaluation and improvement of LCR-DSR channel parameter estimator in mobile communications

Evaluation and improvement of LCR-DSR channel parameter estimator in mobile communicationsThis paper presents a comprehensive investigation on the optimization of a joint estimator employing the double sampling rate (DSR) technique, in which the Doppler shift estimation based on the level crossing rate (LCR) has been evaluated analytically in terms of the mean square error (MSE). Subsequently, the relationship between the MSE and the channel sampling interval is presented for optimization. Finally, the optimal channel sampling interval is obtained as well as an improved performance of the signal-to-noise ratio (SNR) and Doppler shift estimation. Sufficient simulations demonstrate a good performance for the proposed algorithm.

Cramér-Rao lower bound of the channel parameter estimation in mobile communications

Estimations of channel gain, noise variance, and Doppler shift are of great importance in mobile communications. However, the relative motion of the mobile transceiver results in time-varying channels and, therefore, degrades the accuracy of channel parameter estimators. Thus, this paper attempts to characterize such degradations in a general time-selective channel environment, where we derive finite-sample Cramer-Rao lower bounds (CRLB) by assessing the joint effects of Doppler shift (mobile speed), direction of propagation, and additive white noise. These bounds will provide insights into the potential for the estimation of the aforementioned channel parameters. Furthermore, an approximation scheme is proposed in order to tackle the boundary singularity of the channel power spectrum density (PSD). Numerical computations demonstrate that the approximated method produces similar results to the non-approximated method, so long as the sample number satisfies a certain condition. Additionally, the approximated method effectively extends the applicable Doppler range of the non-approximated method.

A novel covert communication system based on symmetric

A novel structure for covert communication is proposed in this study. The correlation coefficient of two adjacent symmetric

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Parameter estimator based on the log-cumulant and its performance analysis for heavy-tailed-distributed impulsive interference}{Parameter estimator based on the log-cumulant and its performance analysis for heavy-tailed-distributed impulsive interference

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