摘要
根据空间精密测距的需求,由多载波最大似然传输时延估计算法的表达式,推导了其克拉美罗界;根据似然函数的形式,提出了一种迭代最大似然时延估计算法.计算机仿真结果表明,所提出的迭代时延估计算法收敛速度快,与使用穷搜索的最大似然方法相比,具有复杂度低的特点;在信噪比为-10 dB的恶劣条件下,同基于相位的多载波测距方法相比精度至少提高了2倍;随着信噪比的增加,性能趋于克拉美罗界.
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 multicarrier 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 multicarrier method at the --10 dB signal-to-noise ratio （SNR）. With the increase of the SNR, the root-ofmean-square-errors （RMSEs） of the proposed method approach the Cramer-Rao lower hound.
出处
《西安电子科技大学学报》
EI
CAS
CSCD
北大核心
2009年第6期957-961,共5页
Journal of Xidian University
基金
国家自然科学基金资助(60602063)
ISN自主课题资助(ISN090304)
高等学校创新引智计划资助(B08038)
关键词
多载波
最大似然
迭代
克拉美罗界
multi carrier
maximum likelihood
iterative
Cramer-Rao lower bound
