Design And Implementation Of GGSN Interface Module Of AGPS Positioning Platform And Improvement Of The Platform

AGPS (Assisted-GPS) is a positioning technology that integrates GPS and mobile telecommunication. Its basic idea is to simplify the terminal's work. It transfers the difficult work like searching for satellites and calculating the position to the positioning platform which is located in mobile network. This technology helps to improve the accuracy of positioning, sensitivity, TTFF (Time To First Fix) and reduce the consumption for battery. Besides this, it can also fallback to non-GPS technology such as CELLID and EOTD when terminal is under dense buildings or indoor circumstance.This paper firstly introduces the AGPS positioning technology and OMA SUPL standards, on which user-plane AGPS positioning is based in GPRS/WCDMA network.In chapter 2 and 3, the author introduces the general architecture design of SLP (SUPL Location Platform), and describes the design and implementation of GGSN interface module in detail. GGSN interface module implements the interface function between AGPS positioning platform and GGSN. It is based on TCP/IP connection, and provides function of bearing most massages of Lup (Location User Plane) interface. Communications between AGPS positioning platform and terminal is implemented by this module.In chapter 4, the author brings up some critical problems when importing AGPS technology, based on simulate test in the lab. Besides positioning function, we also need to solve many problems which are related to the real network and environment, such as privacy, authentication, transferring of IMSI and MSISDN, and pre-setting of SLP address in terminal devices and so on. Only if we solve all these problems, can the LBS based on AGPS be launched in the real network.From chapter 5 on, this paper analyses that background of all the problems mentioned above and proposes solutions including principle, flows modifications and feasibility to the real network according to each problem.