高阶QAM载波恢复的FPGA设计实现

Implementation of high order QAM carrier recovery with FPGA

本文介绍了适用于高阶QAM载波恢复的极性判决算法。该算法利用极性判决器捕获大概频偏,再利用DD算法跟踪并进一步纠正频偏,减小抖动误差,从而相较传统算法具有更好的频偏捕获能力和健壮性。同时,该算法能对两种算法模式进行自动切换以达到精确的频偏纠正目的。本文采用实用有效的MSE方法对这两种算法模式进行自动转换控制,并以128QAM为例对该算法进行MATLAB仿真分析。最后在FPGA平台上实现了128QAM的载波恢复算法,并且效果理想,有很好的移植性。

A polarity decision algorithm suitable for high order QAM carrier recovery is introduced in this paper. It use the polarity decision to capture the rough frequency offset, and then correct the frequency offset more accurately. So the algorithm is more capable in frequency offset capturing and more stable compared with traditional algorithms. Meanwhile, this algorithm can automatically converting the two different algorithm modes. In this paper, the way used to control the converting between the two different modes is MSE. And the simulation in MATLAB about the algorithm is analyzed, using 128QAM for instance. At the last, the whole algorithm is implemented on the platform of FPGA, with desired results and is also portable.