Research On Key Positioning Technologies Based On LTE-A Network

With the continuous development of communication technology,the fourth generation communication technology(4G),are being deployed in the world.Take China as an example,the domestic 4G users continue to increase,and the 4G core network coverage is expanding.With the continuous improvement of mobile communication services,the requirements of the current users are also much higher.The research of the key positioning technologies in LTE-A network are of great significance.As a mature technology,TDOA has been widely used in practical applications.As the application of pattern matching,RFPM technology has a good performance in non-line of sight scenarios,and can optimize the positioning performance by increasing matching parameters.In this thesis,several key positioning technologies of LTE-A network are briefly introduced,including TOA,TDOA,E-CID and RFPM.Secondly,this thesis introduces the OTDOA positioning technology which is well developed in 3GPP protocol.The method of TOA estimation based on the time difference of arrival time is studied.And then the method to obtain the first path through a variable threshold which is based on time delay is proposed.Finally,the content of RFPM positioning technology is studied,including the basic principle of positioning technology,the background of inter-RAT technology and the implementation of RFPM positioning algorithm.Then survey based on pattern matching is used to estimate the position of the measurement parameters.And then according to these parameters,an error model is constructed based on Cramer Rao lower bound.On this basis,combined with multiple access technology parameters measurement,RFPM localization algorithm is improved to realize the constant improvement of precision.The simulation results show that,in the case of handover,RFPM positioning can get better positioning accuracy with the inter-RAT measurement parameters.