基于最大似然理论的CPM定时同步技术

timing synchronization technique of CPM based on maximum likelihood

连续相位调制(CPM)的定时同步算法可以采用基于最大似然理论的估计方法。这种选用前馈结构的无数据辅助算法既适用于全响应的连续相位调制也适用于部分响应的连续相位调制信号,同时也满足多进制和任意调制系数的情况。但该算法对部分响应及多进制信号的同步性能较差,针对算法在部分响应及多进制信号同步中性能不佳的情况,本文提出了一种改进算法。改进后的算法弥补了原算法的不足,提高了同步的整体性能,尤其是在部分响应和多进制的情况下,算法性能得到了明显改善。

The estimation method based on maximum-likelihood theory can be used for timing synchronization algorithm ofcontinuous phase modulation(CPM) . With the feedforward structure, this non-data-aided algorithm is suitable for full responsecontinuous phase modulation and partial response continuous phase modulation(PRCPM), and it is satisfactory for the situationwith multi-ary signal and arbitrary modulation coefficient. However, the synchronization performance of this algorithm is poorwhen used for partial response and multi-ary signal. To solve this weakness, an improved algorithm is proposed in this paper. Theimproved algorithm overcomes the shortage of original algorithm, and it enhances the overall performance of synchronization . Theperformance of the algorithm has been obviously improved especially in the situation with partial response and multi-ary signal.