Research On Waveform Design Of Radar Communication Integration Based On OFDM

At this stage,radar systems and communication systems have made major achievements in their respective development fields.According to the current development trend,found that the demand for integration of electronic systems is increasing.Radar communication integration is one of the fields in integrated systems which is a popular application.Orthogonal Frequency Division Multiplexing(OFDM)technology is often used in the integration of radar communications due to its many advantages.Therefore,this article focuses on the research and design of OFDM-based integrated radar communication waveforms.The main work is as follows:1)First,the advantages and realization significance of radar communication integration are analyzed,and the research status at home and abroad is introduced.Secondly,on the basis of the similarity between radar system and communication system,the achievability of radar communication integration is analyzed,and three available implementation schemes are introduced.The signal sharing scheme is selected to design the integrated waveform.Finally,the structure of the integrated radar communication system is analyzed,and the ambiguity function and bit error rate are used as the criteria for evaluating the performance of the integrated waveform.2)OFDM technology can be widely used in communication systems and radar systems,so this article focuses on OFDM-based radar communication integrated waveform design.The radar performance of the integrated OFDM signal is analyzed from the perspective of the radar ambiguity function.Aiming at the problem that the randomness of the carried communication information affects the detection performance,a precoding-based OFDM integrated radar communication signal is proposed.Using pseudo-random sequences with better correlation characteristics to pre-code the communication data,improve the correlation of the communication data,and achieve the purpose of improving the ambiguity function performance of the integrated signal.In particular,the m sequence,Gold sequence and Kasami sequence are selected for precoding,the characteristics and applicable environment of these three sequences are listed,and the influence of the expansion factor is analyzed.The simulation results show that the ambiguity function and bit error rate of the precoded OFDM integrated signal are significantly improved;when the same spreading factor is taken,these three sequences are used for precoding,which increases the distance of the OFDM integrated signal to varying degrees The peak sidelobe ratio of the ambiguity function can improve the target detection capability of the OFDM integrated signal.3)Compared with the OFDM integrated signal,the precoded OFDM integrated signal has better radar performance,but the addition of precoding technology will reduce the communication rate.To solve this problem,the M-ary spread spectrum technology is combined with the precoded OFDM integrated signal to form an M-ary precoded OFDM integrated signal(MS-OFDM).The simulation results show that,compared with the OFDM integrated signal,the MS-OFDM integrated signal has better ambiguity function characteristics and lower bit error rate;compared with the precoded OFDM integrated signal,the MS-OFDM integrated signal the communication rate is faster.At the same time,under the same conditions,the value of the number of spreading elements has little effect on the ambiguity function of the MS-OFDM integrated signal,but in terms of communication performance,the larger the number of spreading elements,the lower the bit error rate.