基于Costas环的OFDM载波同步算法

针对目前OFDM载波同步算法复杂度高、极耗FPGA资源的问题,提出一种改进方法:对频偏的捕获,在联合使用9个短前导序列和长前导序列估计算法的基础上,采用鉴频环路的方法来消除算法中的除法和取模运算;对于跟踪部分,在使用导频跟踪频偏的基础上,利用Costas环估计相位和剩余频偏;最后综合捕获和跟踪进行系统仿真,得到频偏估计的精度高,范围大,且系统复杂度大大降低的结果.

OFDM Carrier Synchronization Algorithm Based on Costas Loop

This paper puts forward a new approach to the problematic complexity and the accordingly huge FPGA resource cost which are characteristics of current OFDM carrier synchronization algorithms.For frequency offset ac- quisition,we integrate nine short preamble sequences and long preamble sequences to estimate frequency offset,and eliminate the division and modulus operations by using the frequency discriminator loop.For frequency offset track- ing,Costas loop is used to track residual frequency offset and phase on the basis of utilizing pilot to estimate frequen- cy offset.Results of system simulation incorporating both frequency offset acquisition and tracking algorithms indicate less complexity,satisfactory precision and extensiveness of frequency offset estimation.