Research On Position Technology In LTE And Its Evolution System

With the development of LTE and its evolution system,the localization of mobile terminal based on mobile network has become a research focus in recent years.The location information on the terminal side can not only provide Location Based Service,but also provide auxiliary information for channel estimation in beamforming scheme of 5G network under massive MIMO.In particular,after introducing the PRS positioning reference signal in the R9 version of LTE,the mobile network can reduce the positioning error to less than 100m.The related technologies such as millimeter wave communication and Devices-to-Devices(D2D)communication in the LTE evolution system all help to improve the positioning performance of the mobile network.In this paper,we investigate the performance of positioning technology and corresponding positioning algorithm in LTE and its evolution network.The main research contents are as follows:(1)Investigate the mainstream positioning principle and parameter acquisition method in LTE network.Set up a positioning simulation platform.The studied LTE algorithms include positioning algorithm based on received signal reference power(RSS),positioning algorithm based on time difference of arrival(TDOA),positioning algorithm based on multi-base station time advance(TA)and positioning algorithm based on single base station TA and multiple cell IDs.The simulation and positioning results analysis were carried out by using the positioning simulation platform.(2)The TDOA-based least-square localization algorithm is studied.Parameters such as TA,RSS and CID of the LTE base station in the actual network are collected by the test cell phone,and the algorithm is validated.(3)Investigate the relevant positioning architecture and technology under the 5G scenario.A depth search algorithm is designed.Using the designed algorithm,Using algorithms designed to find all the terminals in the measurement area that can be positioned using the three-circle positioning method,and analyze the changes of the overall network positioning performance with the terminal density under the condition of allowing D2D communication.(4)The equivalent bandwidth of five kinds of millimeter waveforms is studied,and the Cramer-Rao lower bound based on the positioning error of distance location is deduced.Through the simulation,the positioning performance of the above five kinds of millimeter waveforms under the same conditions is analyzed.(5)The above work can provide a theoretical reference for the positioning of mobile terminals in LTE and its evolution networks.The research method in this paper is of some reference to the evaluation of the positioning performance in mobile networks.