基于最优化搜索的迭代载波同步算法

码辅助的迭代同步算法将编码增益引入到同步环路中，能够有效实现低信噪比环境下的载波同步。针对低信噪比条件下码辅助同步算法存在参数估计范围小的问题，提出了基于最优化搜索的迭代载波同步算法。该算法通过研究载波偏差与译码软信息的关系，得出一种较简单的评价函数，再利用均匀搜索方式结合改进的Powell算法来获取同步参数的最佳估计，以实现准确的载波恢复。仿真实验验证了该算法在低信噪比条件下，能够有效补偿载波偏移，且具有较大的同步范围，在一定迭代次数之后可逼近理想同步。

An Iterative Carrier Synchronization Algorithm Based on Optimization Search

By introducing the coding gain to synchronization loop, the code aided iterative synchronization algorithm can achieve the carrier synchronization under low signal to noise (SNR) ratio values. Aiming at the problem of small parameters estimation range in the above algorithms, this paper proposes an iterative carrier synchronization algorithm based on optimization search. By analyzing the relation between carrier offset and soft decoding information, the proposed algorithm obtains a simpler evaluation function. Then, the uniform search way is combined with the modified Powell algorithm to get the optimized estimate of synchronization parameters. Thus, the accurate carrier recovery can be achieved. The simulation results demonstrate that, under low SNR, the proposed algorithm can compensate carrier offset efficiently and has larger synchronization range. Moreover, the perfect synchronization can be approximated after several iterations.