OFDM系统中基于PM的时延估计算法

Time delay estimation based on PM in OFDM system

在正交频分复用(OFDM)系统的超分辨时延估计中,针对多重信号分类(MUSIC)算法的特征分解计算复杂度较高的问题,给出一种基于传播算子(PM)的时延估计算法。对OFDM系统进行信道估计,根据信道估计结果计算协方差矩阵,并利用协方差矩阵计算PM,然后根据PM构造出噪声子空间并将其标准正交化,最后利用伪谱函数进行时延估计。仿真结果和复杂度分析表明,在复杂度大幅度下降的条件下,所提算法与MUSIC性能相当,且逼近克拉美罗界。

In Orthogonal Frequency Division Multiplexing（OFDM） system, super resolution time delay estimation shows important application value. The Multiple Signal Classification（MUSIC） algorithm requires eigenvalue decomposition whose computational complexity is very high. A new time delay estimation based on Propagator Method（PM） is proposed for solving the problem. Firstly, the proposed algorithm performs the channel frequency response estimation in OFDM system. Moreover, the channel frequency response estimation can be used for estimating the covariance matrix which can calculate the propagator. The propagator can be used to construct the noise subspace without eigenvalue decomposition, then the noise subspace is orthonormalized for improving the performance. Finally, the pseudo spectral function is constructed for estimating the time delay. Simulation results and the analysis of computational complexity show that the proposed algorithm has the similar performance as the MUSIC algorithm and approaches the Cramer-Rao Bound（CRB） under the condition of the significant decline of the computational complexity.