The Synchronization And Detection Performance Of LFM Based RadCom System

With the development of electronics,lots of communication and radar devices have been applied to military combat platforms and intelligent vehicles,leading to various problems such as energy consumption,complicated scheduling and occupation of resources.To solve these problems,shared waveform for communication and radar(RadCom waveform)is an efficient way to integrate different systems.The existing integrated systems commonly use RadCom waveform improved from linear frequency modulation(LFM)radar waveform while rarely considering synchronization for communication.Therefore,the research in this dissertation focuses on time and carrier frequency synchronization of multiple phase shift keying(MPSK)modulated LFM signal which is regarded as RadCom waveform.Moreover,the radar detection ability of RadCom waveform is also analyzed.Firstly,on the premise of maintaining communication spectrum efficiency,two methods for time synchronization are proposed in Gaussian white noise scenario assuming that only signal delay exists.The feasibility of two methods is proved by theoretical analysis,while the synchronization performance is compared with traditional methods in simulation.Besides,the bit error rate(BER)of RadCom waveform using two synchronization methods is simulated and compared with ideal BER.According to the analysis and simulations,the proposed methods can implement time synchronization while basically not affecting spectrum efficiency.Then,since the received signal may have carrier frequency offset which would interfere time synchronization and demodulation,two methods which can synchronize time and carrier frequency are proposed.The feasibility of two methods is analyzed while the synchronization performance is simulated and compared with traditional methods.Moreover,the BER of RadCom waveform using two synchronization methods is compared with ideal BER in simulation.According to the analysis and simulations,the proposed methods will basically not affect spectrum efficiency during time and frequency synchronization.Next,the spectral extension of LFM based RadCom waveform is analyzed,while the theoretical derivation of ambiguity function is given to investigate the detection performance.Combined with simulation results,the ratio of LFM carrier to baseband data bandwidth is proved to be a significant factor,which determines whether the properties of RadCom waveform are close to LFM carrier or MPSK baseband data signal,further leading to the variation of spectrum and detection performance.