| Detection and analysis of the burst signal is a kind of important technical problems encountered in non cooperative communication receiver. Among them, identification and demodulation of the burst signal is an important part of the analysis on burst signal, relates to the technology widely,including Time of arrival(TOA) estimation, synchronization, channel equalization, signal to noise ratio(SNR) estimation technique and channel coding recognition technology. TOA estimation and SNR estimation is not only the two key technologies of them, but also an important foundation and prerequisite for the burst signal recognition and demodulation. In order to analyze the system theory, to solve a typical practical problems, this paper focuses on the TOA estimation and SNR estimation of the key techniques, discussed several typical algorithms to solve the relevant problems, aiming to do some useful work for the burst signal detecting and processing research, provide a theoretical analysis and technical basis for application of research and analysis for the subsequent signal identification, demodulation and other sudden signal processing.For the TOA estimation part, the paper first studies the typical method for traditional autocorrelation and energy detection of the two kinds on TOA estimation. Through simulation and analysis, on the one hand, the autocorrelation algorithm in low SNR, for the threshold cannot choose cause TOA misjudgment, by using the method of double threshold has made the improvement to the threshold setting;on the other hand, according to the principle of energy detection algorithm, put the correlation algorithm and energy detection algorithm combined, forming TOA two step estimation method for detection, make it better for burst signal. Secondly, through the simulation and comparison, the correlation algorithm of traditional relative energy detection algorithm has a larger advantage. On this basis, focuses on the research of the classic algorithm for first-order autocorrelation SDM algorithm. Through the simulation analysis, the algorithm for distinguishing the received signal(divided into signal and noise exist and are signal or noise exists in two cases), detection performance in the low SNR, smoothing technique three aspects of defect under subsection,by the ratio distribution, wavelet transform and overlap smoothing method has made the improvement to theoriginal algorithm, and improves the detection performance of the algorithm. Finally, combined with the edge detection technology in the field of image processing, analysis a new TOA estimation algorithm based on DOB filter, the difference of the energy and auto correlation detection algorithm, is that don’t need to select threshold, only need to do a convolution, several recursive arithmetic and extremum detection can be completed TOA estimation algorithm, good real-time, high precision of burst detection.For SNR estimation part, based on the same system model to the currently used in the signal-to-noise ratio of the maximum likelihood estimation(ML), signal ratio noise variance(SNV), two order and four order moment(M2M4) and the signal variance ratio(SVR) of four kinds of typical algorithms in real, complex channel. Is deduced, according to the BPSK and the 8PSK two kind of burst signal, the Cramer Rao bound(CRB), normalized mean squared error(NMSE) and estimated standard deviation(NBias) as the evaluation measure algorithm performance standards, through the simulation, the performance of the four algorithms than on, analyze the data length signal to noise ratio, the parameters on the performance of the algorithm, summarized each kind of algorithm for different burst signal in different SNR performance range and data length and the applicability and superiority of the algorithm.Finally, it summarizes this paper, at the same time, the content in this paper, the comments made by the new theory and technology of the existing research content improved and perfected, and the expectation for the future work. |
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