Research On TOA Estimation And Location Algorithms For OFDM System

Wireless location technology used in cellular communication networks is more and more important with the rapid development of wireless mobile communication techniques. Time of arrival (TOA) and time difference of arrival (TDOA) methods are two main methods in wireless location, and how to get accurate TOA measurements is a key factor to realize high accuracy mobile location.This thesis mainly researches on the high-resolution time delay estimation and TOA location algorithms used in Orthogonal Frequency Division Multiplexing (OFDM) systems. The signal transmission delay is estimated by a correlation algorithm in the traditional wireless location system, but the OFDM signals are usually transmitted in the multi-path environment, so the high-resolution time delay estimation algorithms are needed when different multipath time delay are close to each other.First of all, based on the research on TOA estimation signal model and reference to the DOA estimation methods, the subspace based time delay estimation methods which are based on MUSIC algorithm and ESPRIT algorithm in OFDM system are researched separately. The performance of MUSIC and ESPRIT algorithms are simulated in detail under the formation of moderate multipath channel model, and the simulation results verify the efficiency of the algorithms.Then, the TOA location algorithms are analyzed in case of the TOA measurements are obtained. The principle and algorithm of TOA based location methods have been researched, the effectiveness of these algorithms are simulated, analyzed, and discussed. Furthermore, the mentioned methods are simulated in OFDM system under the model of location system and their validities are confirmed. Finally, the total works of this thesis are summarized, and theproblems to be further studied are pointed out.