Research On Key Technologies Of Target Tracking Based On OTFS Modulated Signals

Real-time tracking of the moving object’s location while communicating is a common requirement in mobile scenarios relating to vehicles and unmanned aerial vehicles.On one hand,the orthogonal frequency-division multiplexing(OFDM)modulation technology which is widely used in 4G and 5G has limited resistance to delay and Doppler shift,and the reliability of communication in mobile scenarios will be greatly reduced,thereby affecting the transmission rate and communication delay.On the other hand,the wireless frequency band is increasingly crowded,and wireless signals used for perception and communication interfere with each other,affecting their performances.Therefore,the integration of perception and communication with the same waveform has important application value for the deployment of future large-scale perception and communication networks.Orthogonal time frequency space(OTFS)modulation technology is a new modulation scheme with strong resistance to time-varying channels.OTFS defines information symbols in the delay-Doppler domain,and in radar sensing,the delay and Doppler shift information encountered by moving reflection surfaces in the signal transmission path can be analyzed through this domain,thereby obtaining distance and relative velocity information between the reflection surface and the transmitter.Therefore,this thesis first investigates the current research of OTFS modulation technology and integrated sensing-communicating tracking technology,and considers the feasibility of the tracking technology based on OTFS modulation in the existing communication system framework.Communication and tracking sensing processes were implemented on the OpenAirInterface(OAI)software radio platform integrated with 5G protocol to verify the feasibility of the communication and tracking scheme based on OTFS communication in practical communication systems.The main contributions of this thesis are as follows:(1)To address the problem of reduced communication reliability in 5G cellular mobile network communication systems caused by severe Doppler frequency shift in high-speed scenarios,this thesis proposes a radar communication integrated transceiver design based on OTFS under 5G protocol,which takes advantage of the wide coverage and high packet frequency of cellular mobile networks for sensing,enhances the system’s resistance to Doppler frequency shift in high-speed environments,and improves the communication reliability.OTFS modulation was applied to the physical downlink shared channel(PDSCH),and multiple highmobility reflection paths were added on the basis of the 3GPP EVA channel to enhance interference.The experimental results verified the feasibility of the OTFS modulation technology in the current communication framework and the stronger reliability of communication brought by OTFS modulation in high-mobility scenarios compared with OFDM modulation.(2)Based on the implementation of communication,radar sensing method was used to estimate the moving parameters of the OTFS modulation communication signal.A scheme for modifying and implementing the 5G protocol architecture on OAI to perceive the moving parameters of the OTFS perception-communication integrated signal was proposed,and the radio resource control(RRC)parameters and EVA channel for the base station and user were set in combination with existing high-speed train datasets to simulate actual radar sensing in high-speed scenarios.The experimental results demonstrated the feasibility of implementing OTFSbased perception-communication integrated tracking in the 5G protocol,with a distance estimation error of 4.56%and a speed estimation error of 12.13%in the estimation at a distance of 50m and a speed of 350 km/h,with good estimation performance,where distance estimation is more accurate.