Multi-Component LFM Signal Parameter Estimation for Symbiotic Chirp-UWB Radio Systems

Symbiotic chirp-ultra wide bandwidth (UWB) radio system (SCURS) is a UWB radio system with the symbiosis of linear frequency modulation (LFM) and orthogonal frequency division multiplexing (OFDM) signals.It has a high data rate and can transmit data on two channels simultaneously.Moreover, multi-component LFM (MCLFM) parameter estimation plays an important role in the demodulation of SCURS.Furthermore, the complex electromagnetic environment also brings impulsive noise.In this paper, a novel parameter estimation method for MCLFM signals based on the fractional Fourier transform-bald eagle search algorithm (FRFT-BES) and synchroextracting short-time fractional Fourier transform-Hough (SSFT-Hough) with alphastable noise is proposed.First, we use a nonlinear transformation to eliminate the negative effect of alpha-stable noise on parameter estimation.Second, we combine the improved BES with FRFT to propose FRFT-BES and use it to estimate the frequency modulation rate.Finally, we propose a new time-frequency (TF) transform method with high TF resolution as SSFT, and we combine it with Hough transform (HT) to propose SSFT-Hough to estimate the initial frequency.Frequency modulation rate and initial frequency are widely used in MCLFM signals separation.Simulation results demonstrate that the proposed method performs well in low mixed signal-to-noise ratio (MSNR), and it is superior to existing methods.