Research On Indoor Positioning Of 3GPP-LTE Mobile Terminal

The rapid development of mobile Internet requires that today's wireless communication system should be capable to provide a wealth of location-based services(LBS)-such as indoor positioning,location check-ins,traffic navigation for people.Therefore,the exploration of faster and more accurate positioning technology has become one of the hottest research point in the field of communication currently.The study on indoor positioning of Long Term Evolution(LTE)system is based on the evolution of Long Term Evolution Advanced(LTE-A)which is standardized by the 3rd Generation Partnership Project(3 GPP).Different from two-dimensional positioning technologies introduced in LTE system,the positioning study in LTE-A are more results-oriented on three-dimensional positioning and the integration of various positioning technologies.Currently,the time delay estimation algorithm is the core technology used in main positioning approach because of its low requirement for mobile terminal and physical environment.On the basis of time delay estimation algorithm,we focus more on the performance improvement of Observed Time Difference of Arrival(OTDOA)scheme using Positioning Reference Signal(PRS).The main work and contributions of this paper are as follows:This paper introduces the existing wireless location solutions in current LTE system,and the derivation of Chan/Taylor algorithm under OTDOA positioning solution.Then on this basis,this paper introduces the system-level and link-level simulation platforms set up for this study,and proposes an approximate heuristic formula of bit error rate for Turbo encoding and decoding system while solving the problem encountered by calling the application program interface of LTE system-level simulation platform.The most critical indicator in OTDOA positioning approach for LTE systems is the measurement of reference signal time difference of arrival(RSTD).In this paper we first briefly introduce the timing delay estimation algorithm and evaluation criteria,and then propose some improvements program from the angle of PRS signal and RSTD measurement,and then simulate the corresponding cases under different channel scenarios with performance evaluation.Simulation results show that these improvement approach could enhance the RSTD measurement accuracy.For the vertical location problem in indoor positioning scenario,a simple and hybrid positioning scheme utilizing 3D-MIMO is proposed with its performance simulation result.Besides,given the trend of fusion positioning technology research,we compare the simulation results using Taylor algorithm between OTDOA standalone scheme and OTDOA with GPS as initial positioning input scheme.The results show that initial location data using GPS provided as input for Taylor algorithm can achieve better positioning accuracy.