Deep Neural Network-based Reference Signal Reconstruction for Passive Radar with Orthogonal Frequency Division Multiplexing Waveform

Considering the problem of obtaining the reference signal for passive radar with Orthogonal Frequency Division Multiplexing (OFDM) waveform, the reconstruction method based on "demodulation-remodulation" employs the waveform advantage to obtain a purer reference signal. On this basis, a Deep Neural Network (DNN) reconstruction method that combines OFDM demodulation, channel estimation, channel equalization, and constellation point inverse mapping is proposed to establish a DNN-based reference signal reconstruction scheme. This method can be used to adaptively and deeply excavate the mapping relationship between time-domain received symbols and transmission symbols through network learning, and implicitly estimate the channel response, thereby improving demodulation accuracy and reconstruction performance. Firstly, the acquisition of simulation data sets, the construction and training of DNN are studied in this paper.Then, the comparison between the DNN method and the traditional method about reference signal reconstruction performance is analyzed under the condition that the number of pilots is reduced, the cyclic prefix is removed, the symbol timing offset exists, the carrier frequency offset exists, the time domain windowing filter is performed on the high peak-to-average power ratio signal, and all the above parameters are superimposed. Finally, simulation results show the effectiveness of this method.