电力无线专网中一种OFDM载波同步算法

OFDM carrier synchronization algorithm in electrical wireless network

摘要:

电力无线专网在1.8 GHz频段建设4G TD-LTE网络，正交频分复用(OFDM)是其关键技术之一，OFDM系统对信道产生的载波频率偏移(CFO)很敏感，频率偏移会造成系统性能的严重下降。因此，需要对OFDM系统中的频率载波偏移精确估计并补偿，以保证系统的性能。本文提出了一种用于OFDM系统中基于局部搜索的多重信号分类(MUSIC)盲CFO估计的算法，该算法利用频率偏移矩阵列矢量与噪声子空间的正交性和CFO的单峰特性，构造一个改进空间谱函数，然后通过局部谱峰搜索得到频偏估计值。该算法的CFO估计性能优于传统CFO估计算法，且能够克服传统MUSIC算法低信噪比下谱峰缺失的问题。仿真结果证明了该算法的有效性。

Abstract:

Electrical wireless network constructs the 4G wireless TD-LTE network in the 1.8 GHz band, where Orthogonal Frequency Division Multiplexing(OFDM) is one of the key technologies. However, OFDM is sensitive to Carrier Frequency Offset(CFO) which will result in serious degradation of system performance. Therefore, accuracy of the CFO estimation is significant for the OFDM system and is required to ensure the performance. A blind CFO estimation for OFDM systems via local searching Multiple Signal Classification(MUSIC) algorithm is proposed. The algorithm constructs an improved spatial spectral function by combining the orthogonality between the column vectors of the CFO matrix and the noise subspace, and the single peak characteristic of CFO. The CFO estimation is obtained by local peak searching, and the problem of missing peaks under low SNR in traditional MUSIC algorithm can be overcome. Comparing to the traditional CFO estimation approaches, the proposed algorithm can improve CFO estimation performance. The simulation results validate the effectiveness and superiority of the proposed algorithm.