Signal Analysis And Design For Integrated Communication And Radar System In Vehicular Environments

Recently,in order to improve the road safety,researchers have proposed and deployed intelligent transportation systems(ITS)by making use of advanced information and communication technologies.In the framework of ITS,the future intelligent vehicles(IV)have to work in two manners:wireless communication and radar sensing.This two functions can be achieved through two independent wireless systems.However,integrated communication and radar system(iCars)is a better solution,which can bring a series of advantages,such as low cost,small size,multi-function,low power consumption.The main challenge in iCars development lies in finding suitable waveforms that can be simultaneously employed for information transmission and radar sensing.In this paper,we put forward the integrated radar and communication signal based on OFDM,and lay the foundation for the future study of the ITS.Firstly,the paper introduces the theoretical knowledge of radar system and wireless communication system,mainly including channel mode,OFDM communication signal and OFDM radar signal.The feasibility of radar range and velocity measurement using OFDM communication signal is proved.Secondly,a detailed description of radar ambiguity function has been discussed.Then,a joint signal for integrated communication system and radar system is proposed.This scheme includes three parts.The first part,we proposed all phase precoding scheme,which can improve the time bandwidth product.In the second part,we improve the multi-block OFDM structure,which can satisfy the demand of high speed mobile vehicle network environment.Multi-block OFDM can effectively restrain the sensitivity of inter carrier interference(ICI),and reduce the peak average power ratio of traditional OFDM signal.In the third part,we proposed all phase multi block FFT(APMB-FFT)demodulation technology.APMB-FFT can effectively restrain the spectrum leakage problems of traditional FFT.What's more,APMB-FFT can improve the signal-to-noise ratio of the received signal.Finally,System Simulation of the integrated system based on APMB-OFDM signal is implemented.Simulation results show that APMB-OFDM based joint signal can reduce noise power for about two-thirds,and save about 2dB SNR in the Gaussian channel.The improvement of the signal to noise ratio and the time-bandwidth product are also guaranteed a good anti-jamming capability and range-velocity resolution.