针对低信噪比短突发通信系统的载波恢复问题,研究了一种基于迭代思想的载波相位估计算法。该算法首先利用导频进行初始的载波相位估计,然后再利用Turbo译码器输出的软信息进行载波相位细估计,进而实现有效的载波同步。仿真结果表明,该算法仅利用11个QPSK导频符号就能校正较大范围的相位偏移,进而达到理想的误比特性能。
To solve the problem of cartier recovery in short burst communication system under the condition of low signal-to-noise ratio(SNR), an iterative cartier phase synchronization algorithm is researched in this paper. Firstly, the algorithm utilizes pilot symbols to estimate initial phase value based on maximum likelihood algorithm. Secondly, the soft-information of Turbo decoder is used to estimate fine phase value, and then achieves efficient carrier synchronization. Simulation results indicate that the algorithm can correct a larger range of phase offset with only 11 QPSK pilot symbols so as to achieve optimal bit error probability performance.