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Chien-Sheng Chen 1 and Jium-Ming Lin 2 and Chin-Tan Lee 3 and Chyuan-Der Lu 4
Academic Editor:Chang Wu Yu
1, Department of Information Management, Tainan University of Technology, Tainan 71002, Taiwan
2, Department of Communication Engineering, Chung Hua University, Hsinchu 30012, Taiwan
3, Department of Electronic Engineering, National Quemoy University, Kinmen 89250, Taiwan
4, Department of Finance, Tainan University of Technology, Tainan 71002, Taiwan
Received 29 June 2013; Accepted 25 December 2013; 24 March 2014
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
1. Introduction
The mobile positioning is an important research topic in wireless communication. In recent years, it has gained considerable attention. Several researchers are concentrated on how to achieve higher accuracy in positioning. There are several wireless location schemes such as signal strength (SS), angle of arrival (AOA), time of arrival (TOA), and time difference of arrival (TDOA) techniques. The location of a mobile station (MS) is measured by the TOA between three or more base stations (BSs) with velocity of light [1, 2] in TOA method. The direction of the arrival signal [1] is detected by an antenna array and a directive antenna in AOA scheme where the MS is constrained along a line. The location of an MS is measured by the difference of arrival time between three or more BSs [3] in TDOA method. In particular, time-based and angle-based categories have their own advantages and disadvantages. The angle-based schemes have to know the minimum of two BSs to determine the MS location and the BSs do not require synchronization. On the contrary, the time-based schemes require at least three BSs and need synchronization. However, the time-based schemes usually provide much better positioning accuracy than angle-based schemes. Nowadays, There are a lot of applications of wireless location services, such as the intelligent transportation system (ITS) [4] and the emergency 911 (E-911). The public safety officer can see the caller's phone number and accurate location by E-911, and ITS combines a variety of positioning technologies to enhance the safety and efficiency of the transportation systems.
Non-line-of-sight (NLOS) is an important issue in MS...