Design Of Radar Communication Integrated Waveform Based On OFDM

With the development of electronic information technology,the electromagnetic environment of combat platform has become increasingly complex.In order to cope with the rapidly changing combat situation on the battlefield,how to improve its survivability and combat capability will become particularly important.Therefore,how to integrate radar equipment and communication equipment together to achieve target detection and data communication using limited spectrum resources and space will be the focus of future research.Based on the signal energy sharing,this paper designs an integrated waveform by combining Orthogonal Frequency Division Multiplexing(OFDM)technology with polyphase code and chaotic sequence,and performs subsequent processing on the waveform.The main work and innovations made are as follows:1)The autocorrelation characteristics,ambiguity functions and Doppler sensitivity characteristics of Barker code,frank code and P4 code are compared and analyzed.Simulation results show that P4 code has excellent autocorrelation characteristics and better Doppler sensitivity characteristics.The complementary features of P4 codes can be used to construct P4 cyclic complementary code.Therefore,this paper integrates the communication information into the cyclic shift of P4 code and then performs OFDM modulation as an integrated waveform.2)The characteristics of Logistic and Chebyshev chaotic models are analyzed.And their initial sensitivity and autocorrelation performance are comprehensively compared.Finally,taking the hybrid mapping of them as a chaotic sequence generation model,a DCSK integrated waveform based on packet OFDM is constructed.3)For the problem that the peak-to-average power ratio of the OFDM signal is too high,a simulation analysis is performed on the conventional direct limiting method and partial transmission sequence method to reduce the peak-to-average power ratio.Aiming at the problem that the time complexity of partial transmission sequence method is too high,combined with the excellent characteristics of particle swarm optimization and genetic algorithm,a PSO-GA algorithm is proposed to optimize the phase factor selection of partial transmission sequence method.The simulation results show that the algorithm reduces the time complexity with a small loss ofpeak-to-average ratio performance.4)In order to obtain better peak-to-average ratio performance,this paper proposes the MDPSO-Clipping algorithm based on partial transmission sequence method.The algorithm firstly improves the selection method of the phase factor in the discrete particle swarm algorithm,and then combines it with the direct limiting method.The simulation results show that the proposed algorithm can obtain better peak-to-average performance than the partial transmission sequence method while reducing the system time complexity.5)For the integrated signal designed in this paper,the selection of its waveform parameters is analyzed and the working mode of the radar communication integrated system is given.Then the signal processing algorithm of the receiver is studied.Finally,the communication performance of the two waveforms is analyzed.