For 3gpp-lte Terminal Wireless Location Parameter Estimation And Position Resolution Of Study

Radio location is a technology which makes use of the position parameters, obtained by the radio signal, to estimate the Mobile Station (MS) position. With the release of the Emergent 911 (E-911) call in the USA, many telecommunication companies and scientific research institutes are encouraged to increase their input in the radio location field. It makes the location technology develop rapidly. Many radio signals, such as Chirp, Zigbee, UWB and pilot signals, can be used in the position system. How to improve the accuracy is the priority of radio location.Nowadays, the 3rd generation mobile telecommunication technology has been applied maturely. Relevant products, utilizing Wideband Code Division Multiple Access and Time Division-Code Division Multiple Access, are having taken big market. As the development of the 3G technology, 3G Long Term Evolution was put forward in the end of 2004 and developed rapidly. So far, the standard of LTE physical channels and modulation has been released 9 versions. Some research institutes have done deep studies in this field. This paper will discuss the realization of the LTE location system both from obtaining the position parameters and calculating the MS position. After analyzing the character of the LTE downlink signal, the way to combine the radio location technology with the LTE technology will be provided. The work in this paper also helps the development of the radio location in the 3G area.Firstly, the necessity of researching the LTE MS radio location is brought forward, from analyzing the market environment and the future application. In the beginning of this paper, some well known systems and techniques are shown, as well as the background of the radio location technique is discussed. After that, the challenges of this field are given.Secondly, we analyze the air interface protocol of LTE. The position scheme and signal processing for LTE system is provided. Then, the TDOA (Time Difference of Arrival) estimation algorithm based on downlink of LTE system is deduced, and an appropriate solution is illustrated. From the viewpoint of practical systems, the method of demodulation in the MS is explained.Thirdly, the position algorithms are analyzed in detail. According to the classical algorithms, some improved methods are introduced. For mitigating the NLOS (None Line of Sight) interference, the GBSBEM (Geometrically Based Single Bounce Elliptical Model) is proposed, and the performance of this model is tested by the simulation.Fourthly, a simulation platform for LTE location system is build. The platform is initiative. By comparing it with Ericsson's position scheme, the performance of the proposed location system is better.At last, the conclusion and expectations are presented.