Research On Transmission Method Of MIMO Joint Radar And Communication Assisted By Statistical CSI

With the gradual expansion of the application scope of the 5th Generation Mobile Networks(5G),the number of wireless communication devices is increasing explosively.A subsequent problem is the increasing demand for spectrum resources in wireless communication networks.Research shows that Joint Radar and Communication(JRC)technology can effectively alleviate the plight of spectrum resource shortage.JRC can be divided into two research directions: Radar-Communication Coexistence(RCC),Dual-functional Radar-Communication system(DFRC).At present,most of the research on JRC is based on instantaneous CSI(Channel State Information).Considering that the acquisition of instantaneous CSI requires huge overhead,the acquisition cost of statistical CSI is lower and can be stable for a longer time.Therefore,this paper has carried out the research on JRC transmission method using statistical CSI,and the specific contributions are as follows:Firstly,a waveform design method using statistical CSI to maximize communication rate is proposed for RCC scenarios.Consider a coexistence system that includes a communication base station(BS),a radar BS,and a user.The communication BS,radar BS,and user are all multiple antennas.The communication channel between the communication BS and the user is modeled as a Rice channel with spatial correlation,and the interference channel between the radar BS and the user is modeled as a Line-of-Sight channel.The user will not only receive useful signals from the communication BS,but also receive interference signals and ambient noise from the radar BS.Using statistical CSI,a deterministic equivalent expression of communication ergodic rate is derived based on the large system approximation theory.Under the constraints of communication transmit power,radar transmit power,and radar waveform,a closed form expression of communication beam and radar waveform is designed by maximizing the approximate result expression of communication ergodic rate in a large system.The simulation results show that the derived approximate expression for large scale systems has high accuracy,and the proposed waveform design method can effectively reduce radar interference to communication systems and improve system communication performance.Then,for DFRC scenarios with eavesdroppers,a secure dual function waveform design method using statistical CSI to maximize the security rate is proposed.Consider a system model that includes a DFRC BS,a multi antennas user,and a radar target with eavesdropping capabilities.The DFRC BS and communication users are modeled using a spatial correlation Rice channel,and the target is modeled using a Line-of-Sight channel.Using statistical CSI,a deterministic equivalent expression of the system ergodic safety rate is derived based on the large system approximation theory.Under the constraints of base station transmit power and radar waveform,a closed form expression of the safety dual function waveform is designed by maximizing the approximate result expression of the large system transmit safety rate.The simulation results show that the derived approximate result expression for large scale systems has high accuracy,and the proposed waveform design method can effectively improve the safety rate.