Research On OFDM-Based Radar Communication Sharing Method

As information technology continues to develop,emerging intelligent platforms such as intelligent driving cars and drones are becoming increasingly complex.The requirements for radar detection performance and wireless communication performance of these platforms are also increasing.Therefore,there is a need for a shared system that can simultaneously achieve communication and radar functions.In the research of radar communication sharing systems,designing based on the Orthogonal Frequency Division Multiplexing(OFDM)communication system is relatively representative.The waveform of this system has the advantages of high bandwidth utilization and anti-multipath,which are widely discussed in the radar field and have good radar detection capabilities.However,the traditional OFDM radar communication sharing signal has disadvantages such as low spectrum efficiency,high error rate,and high peak-toaverage power ratio at the communication receiving side.In order to improve the communication performance of OFDM radar communication sharing systems,this paper proposes combining Index Modulation(IM)with OFDM radar communication sharing systems to establish an OFDM-IM sharing system.The OFDM-IM sharing system needs to retrieve the position of the communication subcarrier at the communication receiving end.Compared to traditional Maximum Likelihood(ML)and LogLikelihood Ratio(LLR)detection algorithms,this paper adopts a lower complexity ML detection algorithm that significantly reduces the complexity of ML detection while almost no sacrificing detection accuracy.Simulation results show that the communication performance of the OFDM-IM sharing system is superior to that of the traditional OFDM sharing system,while still maintaining excellent radar detection capabilities.This paper applies the Modulation Symbol Domain(MSD)algorithm to distance-speed estimation in the OFDM-IM shared system.Compared with traditional OFDM systems,there is no difference in resolution between the two systems,but the existence of blank subcarriers in the OFDM-IM system can cause degradation of sidelobes and stronger randomness.To eliminate the disadvantages of the OFDM-IM shared system at the radar receiver,this paper proposes a super-resolution estimation algorithm based on Compressed Sensing(CS)theory,called MSD-SS-CS,which utilizes the sparsity of targets in the distance-speed space domain.Simulation results show that this algorithm can effectively eliminate sidelobes,achieve detection performance consistent with traditional OFDM radar communication sharing schemes,and achieve super-resolution estimation of target distance and speed when the spacing between detection targets is less than the signal resolution.This article proposes an OFDM-IM radar communication sharing system that enhances communication performance without sacrificing radar performance,and achieves radar superresolution range-velocity estimation.It is an excellent method for OFDM radar communication sharing and has certain engineering application value.