Design Of Waveform And Beamforming For Dual-Function Radar-Communication

Mobile communications and wireless network services are in a phase of rapid development,and the conflict between limited band resources and the increasing number of wireless access devices has become one of the important issues to be solved in the future wireless communications industry.Therefore,it is particularly important to realize the reuse of radar band resources in the field of communication,and DFRC(Dualfunction radar-communication)system can effectively realize the spectrum sharing of radar and communication,which can meet the communication needs of downlink users while achieving the detection of the target of interest.In particular,DFRC beamforming design is one of the important technologies to realize the integration of radar communication.In this background,this thesis focuses on DFRC beamforming design,the main research work and innovation points are as follows.1)A DFRC system waveform design framework based on DPC(Detection probability constraint)is proposed for the future requirements of radar communication integration.The framework takes maximizing the communication performance of downlink users as the goal and designs the DFRC BS(Base station)transmit waveform algorithm with the radar detection performance as the constraint.Simulation results show that the proposed design method can effectively solve the resource allocation problem between the radar side and the communication side while ensuring the same detection performance.In addition,when the radar detection performance is saturated,the waveform design redistributes resources to the user side to obtain a higher transmission rate.Compared to traditional Omnidirectional and Directional frameworks,the DPC framework can improve performance on the communication side by appropriately sacrificing radar detection performance.2)In order to improve the physical layer security performance of DFRC systems,a novel DFRC transmit symbol structure is proposed and the SSR(Security sum-rate)is derived.Designing beamforming matrices by maximizing SSR,thus solving the problem of secure system transmission by DFRC when the Eve(Eavesdropper)state information is unknown.The proposed structure can directly use the radar function to determine the Eve existence state and infer whether the transmitting information needs to carry artificial noise to interfere with the Eve based on the Eve state information.Subsequently,the beamforming matrix is designed by establishing the optimization equations based on Eve states.The simulation results show that the proposed structure can effectively solve the system physical layer security problem and obtain higher SSR when Eve state information is unknown.And the beamforming matrix designed allows for a trade-off between radar and communication.