基于循环自相关的OFDM时间参数盲估计改进算法研究

在非协作通信领域,传统的基于循环自相关的OFDM(Orthogonal Frequency Division Multiplexing,正交频分复用)时间参数盲估计算法常分析的是无导频OFDM信号,不适用于实际应用场景中含导频OFDM信号的参数盲估计。本文分析了不同导频图案的OFDM信号循环自相关谱特性,针对谱特征变化改进了OFDM信号参数估计算法。改进算法既适用于无导频OFDM信号,也适用于不同导频图案的OFDM信号。仿真结果表明,对于无导频OFDM信号,改进算法比传统算法的时间参数估计误差可降低一个数量级;同时改进算法有效避免了导频引入的二阶周期性谱峰对OFDM时间参数估计的影响,可精确估计含导频OFDM信号的时间参数,具有很好的鲁棒性和应用价值。

Research on Blind Estimation Improved Algorithm of OFDM Time Parameters Based on Cyclic Autocorrelation

In the field of non-cooperative communication, the traditional OFDM time parameter estimation algorithm based on cyclic autocorrelation analyses the OFDM signals without pilots, which is not suitable for the parameter estimation of the OFDM signals with pilots in the actual application scene. In this paper, the cyclic autocorrelation spectrum characteristics of OFDM signals with different pilot patterns are analyzed, and the OFDM signals parameter estimation algorithm is improved for changes of the spectral feature. The improved algorithm is applicable to both OFDM signals without pilots and OFDM signals with different pilot patterns. Simulation results show that, for OFDM signals without pilots, the improved algorithm can reduce the time parameter estimation error by one order of magnitude over the traditional algorithm. At the same time, the improved algorithm effectively avoids the influence of the two-order periodic spectral peaks introduced by pilots to the estimation of OFDM time parameters. It can accurately estimate the time parameters of the OFDM signals with pilots, and it has good robustness and application value.