Research On Key Technologies Of Radar-Assisted Communication-Sensing Integration

Dual-function radar and communication is an important direction in the 6th generation mobile communication(6G)technology research.Radar technology can provide parameter information of the targets of interest,while communication technology can carry out valuable data exchange and transmission.The principles,resources,devices and signal processing methods of radar detection and communication transmission are similar.Combining radar and communication technology is capable of achieving more intelligent,efficient,safe and reliable communication and control,which has a wide range of application prospects in the Internet of things(IoT),automatic driving,unmanned aerial vehicles and even military fields.There are three integration modes of radar communication integration:time-sharing system,beam splitting system and simultaneous system,among which the simultaneous system has the highest degree of integration.In the simultaneous system,radar and communication use the same electromagnetic waves for communication information transmission and target detection,which can save hardware resources and have a higher degree of freedom.Therefore,this thesis focuses on the method of simultaneous regime integration based on different waveforms.First of all,for the dual-function radar and communication based on the radar waveform,this thesis focuses on the research of designs based the classic linear frequency modulation(LFM)waveform.LFM is a commonly used waveform for vehicle radar detection.It has the characteristics of large time-width bandwidth and high-precision target detection capability.The main focus of LFM-based integrated method research is how to load more communication transmission information while minimizing the impact on perception performance.To this end,this thesis adopts a method based on multidomain joint modulation for information transmission,which improves the ability of information transmission,and combines offset space modulation and antenna selection with the system,which can further reduce the bit error rate while increasing the communication rate.Secondly,for the dual-function radar and communication based on communication waveforms,this thesis focuses on the research of orthogonal frequency division multiplexing(OFDM)waveforms and the evolution waveforms.Not only the digital standards and characteristics of the different waveforms are summarized,but also the performance gaps between them as integrated waveforms are compared.This thesis considers three main performance metrics for comparison:time-domain peak-to-average ratio,communication transmission bit error rate,and radar target hit rate.Through simulation comparison,it is found that discrete Fourier transform-spread-OFDM with index modulation(DFT-S-OFDM-IM)is capable of providing promising benenifts in the field of peak-to-average power ratio and communication bit error rate.In terms of radar performance,OFDM waveform has the best hit rate performance among all waveforms considered while DFT-S-OFDM-IM is suboptimal.Finally,for the typical integrated vehicle networking application scenario in 6G,this thesis is centered around a target beam tracking method of radar-assisted communication,which can simultaneously realize downlink communication and uplink feedback.Under the straight-line path,the performance comparison of different filters for target tracking is realized,and the LFM integrated waveform is applied to this scene.In addition,a more widely applied curved path is also considered in this thesis,and tracking modeling and simulation of different target parameters are completed.