Demodulation method of dqpsk modulated signal based on cnn and lstm

Abstract

The invention provides a CNN (Convolutional Neural Network) and LSTM (Long Short Term Memory)-based DQPSK (Differential Quadrature Phase Shift Keying) modulating signal demodulating method, and solvesthe technical problem of high demodulating error rate in an existing DQPSK signal demodulating method. The method comprises the following realizing steps: acquiring a sampling sequence and a symbol sequence of a DQPSK modulating signal; constructing a CNN and training the CNN; constructing an LSTM and training the LSTM; acquiring an output sequence of the trained CNN; determining sampling data corresponding to each code element period of the DQPSK modulating signal in the sampling sequence; and acquiring a demodulating result of the to-be-demodulated DQPSK modulating signal. According to theCNN and LSTM-based DQPSK modulating signal demodulating method, a boundary of a code element of the DQPSK modulating signal is judged through the CNN, and the problems of Doppler frequency shift, a sampling clock error and the like can be solved; acquisition of demodulating data of the DQPSK modulating signal is directly completed by using the LSTM; and the problem of high demodulating error ratecaused by an uncertain boundary of the code element of the modulating signal is solved.

Description

technical field [0001] The invention belongs to the technical field of digital communication, relates to a DQPSK modulation signal demodulation method, in particular to a DQPSK modulation signal demodulation method based on CNN and LSTM, which can be used for satellite communication and deep space communication. Background technique [0002] In order to transmit a digital signal in a bandpass channel, the carrier must be modulated with a digital baseband signal to match the signal to the characteristics of the channel. This process of controlling the carrier with a digital baseband signal and converting the digital baseband signal into a digital bandpass signal is called digital modulation, and the process of restoring the bandpass signal to a digital baseband signal through a demodulator at the receiving end is called digital demodulation. Digital modulation includes phase shift keying (Phase Shift Keying, referred to as PSK), amplitude shift keying (Amplitude Shift Keying,...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art, and provides a method for demodulating DQPSK modulated signals based on CNN and LSTM, which is used to solve the high bit error rate existing in the existing DQPSK modulated signal demodulation method technical issues

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