3 Gpp Lte Collaboration Architecture Terminal Positioning Technology Research

Since the U.S. Federal Communications Commission (FCC) published the E-911standards of the cellular networks wireless location technology, a lot of mobile communication system have been formulated to develop relevant positioning scheme, which also include3GPP LTE. In the3GPP LTE system, there already are mainly three types of position scheme:observed time difference of arrival(OTDOA), enhanced cell-ID(E-CID) and assisted global satellite system(A-CNSS).Because the cooperative communication technology was proposed in the later development stage of the LTE system, the cooperative positioning technology among the mobile terminals has also correspondingly become a focus of research.Firstly, this paper describes the development of wireless location technology, and expounds all kinds of positioning technology principle and implementation plan in the background of LTE. At the same time, we discussed and summarized variety of TOA positioning parameter estimation methods of the OFDM signal.Secondly, this paper described the cooperation communication technologies in the LTE system, and on this basis, developed the cooperation concept in the LTE wireless positioning system. A new location strategy that called differential cooperative positioning was proposed as the first cooperation scheme. Through numerical simulation the feasibility of difference cooperation position strategy was proved.Finally, semi-definite programming method is used in the cooperative positioning in the LTE system. Semi-definite programming is a promotion of linear programming, its theory and algorithms have made a great progress in recent years, and are widely used in engineering applications. In this paper, cooperative positioning in the heterogeneous network structure in LTE system will be transformed into a mathematical programming problem, and the semi-definite programming relaxation model will be used to solve the cooperative positioning problem. We firstly proved its feasibility by numerical simulation. Next, considering the NLOS’s impact to positioning accuracy of mobile station, we established a semi-definite programming relaxation model based on the weighted NLOS error and an iterative semi-definite programming relaxation model based on the suppressed NLOS error. The numerical simulation showed that this cooperative positioning methods can improve the positioning accuracy under NLOS condition.