对高阶QAM信号盲载波相位捕获算法的一种改进方法

Method to improve the performance of blind carrier phase acquisition algorithms for high order QAM signals

现有高阶QAM信号的载波相位捕获算法存在着估计精度不高的缺点,它使信号在捕获阶段不能被高质量的解调。为了克服这个问题,提出了利用现有的捕获算法估计得出一个粗略相位值,然后设定一个恰当的范围进行最大似然的迭代搜索,经过一定次数的迭代处理之后估计的精度大大提高。文中还对这种改进方法进行了简化,在保证估计性能基本不变的前提下,极大地降低了运算量。

The existing blind carrier phase acquisition algorithms could not give a precise phase estimation, so in the phase of acquisition, the signals could＇t be demodulated with high quality. To overcome this problem, a new method improving the performance of acquisition algorithms was developed. First a coarse phase estimation value was given by existing acquisition algorithm, and then a maximum-likelihood iterative search was used to approach the actual value within a proper range. After several times of iterative processing, the estimation precision was improved greatly. The method to reduce the computational complexity is also proposed which can reduce the load of computation greatly while the estimation performance doesn＇t degrade obviously.