一种LOFDM系统定时和频偏的盲估计算法

Blind Estimation of Symbol Timing and Carrier Frequency Offset in LOFDM Systems

基于网格正交频分复用(LOFDM)信号的周期平稳性,该文提出一种LOFDM系统定时和载波频率偏差的盲估计算法。理论分析和仿真实验证实由该算法构造的估计器能够有效地对抗频率选择性慢时变信道引起的衰落;在信道噪声广义平稳的情况下,估计器性能与信噪比无关,于是估计器在低信噪比条件下也能很好地工作;另外,符号定时和频率偏差估计器的性能互不影响。

Blind synchronization algorithm is developed for estimating jointly timing and carrier frequency offset of Lattice Orthogonal Frequency Division Multiplexing （LOFDM） systems, which is based on the cyclostationarity of LOFDM signals. The theoretical analysis shows that the following characters are occupied by the proposed algorithm. The proposed estimators can effectively combat the fading caused by the frequency selective slowly time-varying channels. In the case of wide-sense stationary noise, the performance of the estimators is independent of Signal-to-Noise Ratio （SNR） received, and then they operate well in low SNR. Moreover, the performance of the symbol timing estimator and that of carrier frequency offset estimator do not influence each other. Finally, simulation results demonstrate the performance of the presented estimators.