Integrated Waveform Design Of Radar And Communications Based On OFDM

In recent years,with the continuous development of information technology,intelligent driving cars,unmanned aerial vehicle and other emerging intelligent platforms have become increasingly complex,and the system has increasingly higher requirements for radar functions and wireless communication functions.Therefore,designing a signal that can not only detect targets but also transmit communication information is needed urgently.This thesis focuses on the key technology of integrated radar and communications based on OFDM signal,and proposes effective solutions on the waveform design of short and long distance target scenes and radar receiver processing methods.The main contribution consists of two parts:(1)Firstly,this thesis designs an integrated radar and communications scheme under short-range target scenarios.For smart driving scenarios,in view of the existing OFDM-based integrated waveforms,some subcarriers are used for radar detection,and the rest are used for communication data transmission.Aiming to the low spectrum efficiency due to a number of pilots a joint radar and communications waveform based on OFDM and index modulation is proposed.The integrated waveform design scheme IMP-OFDM can be used in detecting short-distance target scenes.In order to ensure the accuracy of radar estimation,a multi-target detection method based on pulse compression and two-dimensional Fourier transform is proposed,which can reach the range resolution of 0.1m and the velocity resolution of 0.58m/s.The relationship between radar and communications performance under the proposed IMP-OFDM is analyzed.This scheme can improve both radar and communications performance at the same time under reasonable parameter settings.(2)This thesis also designs an integrated radar and communications scheme for long-distance target scenarios.The maximum unambiguous range that the radar can detect under the IMP-OFDM scheme is only suitable for detecting short-range targets due to the limitation of the number of pilots.Therefore,this thesis proposes a PIMP-OFDM radar and communications integrated waveform that is index modulated by pulse groups for long-distance target detection scenarios.The receiving end performs pulse compression and reconstructs on the pilot matrix to achieve the target velocity and range measurement.Compared with the integrated waveform solution based on stepped pilots,this scheme can reduce the impact of target movement on target range measurement,eliminate undesired peaks and transmit a portion of data bits additionally.