Design method of frequency agile transmit signal of ofdm based on cyclic prefix

Abstract

The present invention proposes an OFDM frequency agile transmit signal design method based on cyclic prefix. It mainly solves the problem of mutual crosstalk of echo energy between different distance resolution units in the prior art. The implementation scheme is: serial-to-parallel conversion of the transmitted signal data sequence; design random hopping subcarrier frequencies; add a cyclic prefix CP to the OFDM transmitted signal; construct the subcarrier transmitted signal according to the random hopping subcarrier frequency, and use parallel data sequences The sub-carrier signal is modulated to obtain the modulated sub-carrier signal; the modulated sub-carrier signal is superimposed to obtain the OFDM frequency agile transmit signal based on the cyclic prefix, and the transmit signal design is completed. The simulation results show that the pulse compression of the echo signal by using the frequency agile transmitting signal designed by the invention can reduce the range side lobe of the radar and effectively suppress the interference of the range side lobe to the target. It can be applied to radar range sidelobe suppression, radar detection of weak targets and radar imaging.

Description

technical field [0001] The invention belongs to the technical field of signal processing, in particular to an orthogonal frequency division multiplexing OFDM frequency agile transmission signal design method, which can be applied to radar range sidelobe suppression, radar detection of weak targets and radar imaging. Background technique [0002] The range sidelobe is that the energy of the radar echo signal is diffused in the similar range resolution unit after matched filtering, which will cause the weak target to be covered by the stronger target sidelobe, resulting in the loss of the target or the generation of false targets. At present, the OFDM signal design in the radar only utilizes the flexibility of the OFDM signal to optimize the design parameters. However, the cyclic prefix CP of OFDM in the communication system is not fully used in the radar system. In a communication system, adding a CP to an OFDM transmission signal can achieve no intersymbol interference in t...

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Problems solved by technology

However, the simulation results show that the autocorrelation function of the non-constant modulus sequence designed by this method is low, and the side lobe is still high, and only the non-constant modulus sequence can complete the zeroing of the side lobe in a specific area

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