Td-scdma Cellular Network Based Wireless Location Technology Research

In recent years, with the mobile communication network from 2.5G to 3G, location services become the one of the most competitive 3G core services, it will be an essential function of 3G network. In addition to location technology provide location information for mobile users, it also can play other roles, such as information search, intelligent transportation, advertising, etc. Mobile location technology is concerned by more and more people. This thesis researched on wireless location technology based on TD-SCDMA cellular networks.Firstly, this thesis describes vary of wireless location technology in the cellular network, analyzes and compares the advantages and disadvantages of different location method. Then discusses key technologies of TD-SCDMA systems, analyzes positioning scheme and positioning method which used in the TD-SCDMA system. Adopting location schemes in the current cellular systems are: network-based location, mobile-based location, mobile-assisted location, network-assisted location, GPS-assisted location. This thesis researches network-based location. The main location methods are: angle of arrival (AOA) location method, time of arrival (TOA) location method, time difference of arrival (TDOA) location method and hybrid location methods. TD-SCDMA system uses smart antenna technology, the base station can accurately measure the value of AOA, however location accuracy of TDOA is relatively high and implement easily, it is currently the most common and most important of location technology.This thesis introduces separately several conventional algorithms in both AOA and TDOA location technology, and analyzes and compares the characteristics of various algorithms. As a single location technology has some limitations, while using hybrid location technology can measure more than characteristic value, integrated the advantage of various location methods to implement mobile terminal location. Finally, the thesis mainly researches hybrid location technology. On the basis of the basic TDOA / AOA hybrid location algorithm, PSO-based TDOA / AOA hybrid location algorithm is proposed, and algorithm model is established. The algorithm is verified that the location performance is superior to a single location algorithm by experiments, and can achieve higher location accuracy. Prove the validity of algorithm.