Research On Digital Beamforming Technology Of OFDM Radar-Communication Integration System

Digital beamforming(DBF)technology is wildly used in military and civilian areas including radar,communication,etc,as a main research content in array signal processing.In the internet of vehicles,the combination of DBF and OFDM signal in the radar-communication integration system can estimate the angles of targets to get full environmental information with range and velocity algorithms,and improve resolution of radar sensing algorithms as well as the performance of bit error rate in wireless communication because of the array output signal to interference plus noise ratio increased.This paper proposes a positioning algorithm based on DBF so as to locate multi-targets with range and velocity information,against the real-time demand of internet of vehicles.The main study work of this paper is as follows:(1)A fast DOA-Doppler estimation algorithm is proposed based on beam space using DBF.First,using an improved beam space root-MUSIC algorithm to estimate DOA,with no need of eigenvalue decomposition and peak searching.Then,a beam is formed to receive signals to get Doppler frequency one by one according to DOA,which can match DOA with velocity so as to locate targets.(2)The effect of DBF technology in the integration system for radar application and communication application is studied.For radar,DBF can improve the performance of range and velocity algorithm.For communication,simulations and analysis on pre-FFT beamforming and post-FFT beamforming compared to traditional OFDM system are shown using bit error rate as the communication performance indicator,respectively.Simulation results show that the proposed algorithm has less calculation but with good angle estimation resolution,which meets the real-time requirement in the integration system.In addition,targets location can be achieved matching DOA with Doppler frequency by DBF.Moreover,DBF technology can improve the radar and communication performance in the integration system with higher range and velocity resolution as well as lower bit error rate.