Research On Key Technologies In Integrated Sensing And Communication Based On Wireless Channel State Information

With massive deployment of the 5th Generation Mobile Communication System(5G),research of the 6th Generation Mobile Communication System(6G)has been put on the agenda,where the academic circle and industrial circle reach a consensus that integrated sensing and communication(ISAC)will be one of 6G’s native abilities.ISAC refers to the unified design of sensing and communication by reusing time-frequency-space resources,sharing hardware devices,designing protocols jointly,etc.The communication systems will acquire some sensing abilities in ISAC,and in the meanwhile high-resolution sensing will aid communication systems in jobs such as pre-coding and beam alignment,which brings performance gains and new commercial values.At present,the research of ISAC is still in its infancy,and there are still great challenges in areas such as integration mode and algorithm universality.Based on the in-depth study of the research background,technologies and current status of ISAC,this paper focuses on the research of localization and environment sensing technologies.The content of this paper is arranged as follows:First,this paper studies the channel state information(CSI)-based simultaneous location and velocity estimation algorithm in millimeter-wave(mm Wave)systems.The proposed algorithm uses the channel model based on the azimuth angle,elevation angle,delay and Doppler shift in accordance with a mm Wave OFDM system using uniform planar array antennas.The Newtonized orthogonal matching pursuit(NOMP)algorithm is then extended and used to extract all propagation paths and their channel parameters from the received CSI.A density-based clustering algorithm is used to filter out all line-of-sight(Lo S)paths,and the linear equations of location and velocity are built based on the channel parameters of Lo S paths.The linear equations are solved by a weighted least square algorithm.Finally the estimations are fed back to the NOMP to reduce computational overhead of next runs.Numerical experiment based on ray-tracing shows that the proposed algorithm is able to achieve high accuracy in location and velocity estimation.Then,this paper studies the localization algorithm for non-half-wavelength array antennas.Limited by the cost,common Wi Fi devices usually use small-scale array antennas,and the array seldom meets the half-wavelength requirement,which brings ambiguity in the CSI phases.Two algorithms are proposed in this paper to solve this ambiguity.The multi-access point(AP)localization algorithm solve the ambiguity by utilizing multiple Lo S samples form different APs,while the reconfigurable intelligent surface(RIS)-assisted localization algorithm uses the ambiguity-free RIS-UE path to perform localization.Two numerical experiments in different scenarios are conducted to prove the effectiveness of the algorithms,respectively.Finally,this paper studies the environment sensing algorithm based on a mm Wave beamscan system.The proposed algorithm uses virtual anchors,which are the mirror locations of the base station to the reflectors,to describe the locations of reflectors in the environment.The propagation paths reaching UE can be seen as sent by the base station and virtual anchors.The angles of these propagation paths can be measured by a beam-scan system,and are used to estimate the location of UE and virtual anchors by the simultaneous localization and mapping(SLAM)algorithm.An OFDM system equipped with a mm Wave phased array is used,which adopts a 5G-like frame structure to schedule the time-frequency resources and beam-scan procedure.To validate the proposed algorithm,the system is tested in two different scenarios,the result of which shows that the algorithm can achieve good performance in user localization and environment sensing.