一种优化的OFDM符号定时与频偏估计算法及其FPGA实现

An Optimized Symbol-timing and Frequency Offset Estimation Algorithm for OFDM System and Its Realization on FPGA

符号定时与频偏估计是OFDM系统中的关键技术之一。本文分析了符号定时偏差与载波频偏对OFDM系统性能的影响,提出了一种优化的最大似然同步算法,并给出了在FPGA中的硬件实现方案,得到其仿真结果。传统的循环前缀符号同步算法,仅仅利用一个OFDM符号的循环前缀及其相应部分的相关性,其相关峰值不明显,同步效果不理想。本文提出一种充分利用连续多个OFDM符号同时进行相关功率运算,在同样信噪比的情况下,相对于单个OFDM符号进行同步估计的系统,符号定时与频偏估计的精度更高,误差更小。

Symbol timing and frequency offset estimation is a key technology of OFDM. This paper analyses the influence of symbol timing and frequency offset on OFDM system, proposes a new optimized synchronization method, gives the hardware design on FPGA, including the simulation results. Different from the traditional way, which only uses one OFDM symbol＇ s cyclic prefix to calculate the correlation, the peak value of correlation is not apparent. This new synchronization method uses multi-continuous OFDM symbols to compute the correlation power. In the same signal to noise ratio, the synchronization accuracy is much higher while the error rates is much lower as compared to the traditional method.