Abstract
To overcome the performance degradation of conventional Chirp parameters estimation methods in underwater acoustic multipath channels, a novel parameters estimation method based on Fractional Fourier transform (FRFT) and Fourier transform (FFT) was proposed. Firstly, the Chirp rate was estimated by searching for the best degree of Chirp after Fractional Fourier transform. Secondly, the Chirp signal turned into a single-frequency signal by means of Chirp rate equalization. Finally, FFT was applied to estimate the initial frequency. The simulation experiment show that the proposed algorithm enhanced about 1dB RMSE performance on Chirp initial frequency compared with FRFT while the computational complexity is similar to FRFT.
Highlights
Chirp, a mature non-stationary signal, is widely used in radar and underwater acoustic communication
The multi-component Chirp signal was estimated by Fractional Fourier transform (FRFT) in [7]. [8] analyzed the estimation performance of FRFT for Chirp parameter estimation and the estimation performance of different discrete algorithms. [4] utilized the FRFT origin moment as statistic to estimate the parameter of Chirp. [9] proposed a method for detecting and estimating the Chirp signal via simple fractional Fourier under the condition of low signal to noise ratio. [10] proposed an improved FRFT algorithm to improve the precision of parameter estimation in the case of low duty ratio
To solve the above problems, this paper proposes a parameter estimation method based on FRFT and FFT for underwater acoustic channel and it does not need to transmit training sequence
Summary
A mature non-stationary signal, is widely used in radar and underwater acoustic communication. In the context of traditional wireless channels, many domestic and foreign scholars have proposed many methods of parameter estimation for Chirp signals, such as ML[1], the short-time Fourier transform[2], wavelet transform[3], Wigner-Hough transform[4], Wigner-Ville distribution[5] and FRFT[6]. [9] proposed a method for detecting and estimating the Chirp signal via simple fractional Fourier under the condition of low signal to noise ratio. In practical applications, Chirp signals are widely applied in underwater acoustic communication. The proposed algorithm has an estimated performance decline under the background of underwater acoustic multipath channel. To solve the above problems, this paper proposes a parameter estimation method based on FRFT and FFT for underwater acoustic channel and it does not need to transmit training sequence. Theoretical analysis and simulation results show that the proposed algorithm can improve the performance of parameter estimation
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