Research On Multi-carrier Ranging Systems And TOA Estimation Algorithms

Firstly, research background and current situation for time of arrive (TOA) estimation are introduced in this paper. Then traditional ranging systems and TOA estimation algorithms are introduced. Moreover, orthogonal frequency division multiplexing (OFDM) ranging systems and TOA estimation algorithms are researched. Finally, orthogonal frequency division multiple access (OFDMA) ranging systems and TOA estimation algorithms are discussed.This paper is focused on orthogonal frequency division multiplexing (OFDM) ranging systems and TOA estimation algorithms. The OFDM ranging system is introduced at first. Then the training symbol is designed. After that a phase difference method is introduced. The simulation results show that the accuracy and the measurement range of the phase difference method are highly improved. In order to further improve the accuracy, a new iterative algorithm for TOA estimation is proposed base on the form of the maximum likelihood function, and the Cramer-Rao low Bound (CRLB) is derived. The simulation results show that the proposed method is of high convergence rate. Compared with the exhaustive searching method, its complexity is low. The ranging accuracy of the proposed method is at least 3 times that of the phase difference method at -10dB signal-to-noise ratio (SNR). With the increase of the SNR, the root-of-mean-square-errors (RMSEs) of the proposed method approach the Cramer-Rao low bound.The performance of four kinds of available TOA estimation methods for the orthogonal frequency division multiple access (OFDMA) system is also discussed in this paper, and the optimal methods are found after comparison.