关键词: 多载波, 最大似然, 迭代, 克拉美罗界

Abstract:

According to the requirement of the precise space ranging, the Cramer-Rao Lower Bound (CRLB) is derived for the maximum-likelihood (ML) transmission delay estimation algorithm in multi-carrier systems from its expression. Based on the form of the likelihood function, a new iterative algorithm for delay estimation is proposed. Simulation results show that the proposed method leads to a 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 measurement based multi-carrier method at the  -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 lower bound.

Key words: multi-carrier, maximum likelihood, iterative, Cramer-Rao lower bound