A study on efficient ranging algorithm based on TOA for indoor geolocation applications

Abstract

With rapid increase of interests in location-based applications for indoor environment, there has been intensive endeavors to develop accurate location estimation technology. The conventional location measurement techni such as GPS is not suitable for indoor system. This is because the existing GPS system is designed for the outdoor application system. Thus, it cannot provide an accurate estimation in indoor environment. Since there are commonly a lot of object which cause multipath fading, it is difficult to estimate the exact range. To deal with these problems, many high resolution methods have been suggested up to now, e.g., MUSIC, minimum-norm, ESPRIT, etc. However these schemes require high computational efforts to estimate the range. Even under the unfavorable circumstances, we need to find the indoor location awareness techniques with high ranging acquisition yet low computational complexity. In this thesis, the process and problem of fundamental location sensing method are presented first. Then TOA estimation techniques are intensively studied in indoor multipath channels, including the MU-SIC and Matrix Pencil techniques. The validity of proposed methods is proved by simulation results with respect to performance. For the complexity analysis, the algorithm complexity is calculated as the total number of real operations. These validity are performed under the assumption that the transmitted signal is used as the impulse signal when the 2 tap channel model is considered. It is shown that the conventional super resolution technique (e.g., MUSIC) has high complexity, whereas the proposed ranging system model using Matrix Pencil has a very low complexity. In case of using the averaging preamble and MMSE cancelation, it can also significantly improve the performance of the TOA estimation in indoor environment. The superior performance of proposed algorithm is demonstrated by simulation result in the 802.15.4a indoor channel environment. In summary, the res...