Research On Technology Of Dual Functional Radar-communication Waveform Trade-off Design

With the development of information technology and mobile communication technology,5G is evolving towards 6G in both technological and business aspects.Emerging businesses such as AI,immersive experiences,and digital twins are constantly emerging,while spectrum resources are becoming increasingly scarce.In complex business scenarios,communication functions and sensing functions interact with each other and overlap in the spatiotemporal domain,presenting a highly integrated trend.Emerging businesses are demanding higher end-to-end information processing capabilities for 6G networks,making communication-sensing integration technology a key factor in the development of 6G technology and business.Communication-sensing integration technology aims to build a dual-function radar communication system,which utilizes the same hardware platform,spectrum resources,and transmission waveform to achieve both radar and communication functions.This solution not only effectively alleviates spectrum congestion but also improves the performance of both.Currently,the core of the dualfunction radar-communication system is the design of the dual-function waveform.Existing waveform design works involve two approaches: the first approach is to embed communication information into radar waveforms,which are designed around the radar;the second approach is to use communication signals to achieve radar detection,which are designed around communication;The third approach is collaborative design of dual function waveforms,which simultaneously achieve radar and communication functions.While these two approaches achieve communication-sensing integration to some extent,they may cause poor performance for either radar or communication.Therefore,this thesis proposes a compromise optimization design scheme for dual-function radarcommunication waveform based on the third integrated waveform collaborative design approach.The main work is as follows:1.In this thesis,we proposes a trade-off optimization design for dual-function radar communication waveforms based on constant modulus constraint to address the waveform distortion caused by radar amplifier over-saturation.The design considers introducing constant modulus constraint at the MIMO radar end to reduce transmission distortion and pre-coding factor at the MIMO communication end to reduce interference between multiple users and improve the communication performance loss caused by the constant modulus constraint.A three-variable non-convex optimization problem is constructed.A multi-variable alternating minimization framework is adopted to decompose the optimization problem into two convex sub-problems and one non-convex sub-problem for iterative solutions.A discrete binary particle swarm algorithm is used to calculate and solve the non-convex sub-problem.Simulation results show that the trade-off optimized design significantly reduces waveform transmission distortion and achieves good communication performance.2.In this thesis,we also proposes a trade-off optimization design scheme for dual-function radar communication waveform based on peak-to-average power ratio(PAPR)constraints to address the problem of excessive communication performance loss caused by low sidelobe levels of constant envelope waveforms.In the MIMO radar system,the PAPR constraint is introduced to control the waveform’s peak value and sidelobe within a reasonable range,ensuring radar performance while reducing communication performance loss.In addition,in the MIMO communication system,the transmission energy is limited.Thus,a single-variable non-convex optimization problem is constructed.The nonlinear equality constraint alternating direction multiplier method is used to decompose the non-convex optimization problem into three convex sub-problems for iterative solution.Simulation results show that the optimized dual-function radar communication waveform can approach the ideal radar waveform,and its communication performance is significantly improved compared to the constant envelope waveform.