MPSK/MQAM符号速率估计算法

为了在复杂环境以及低信噪比情况下实现符号速率的准确估计，降低算法的复杂度和运算量，提出一种针对MPSK/MQAM(multiple phase shift keying/multiple quadrature amplitude modulation )类信号符号速率估计的新方法，通过对A/D采样后的信号进行数字下变频处理得到零中频信号，利用I路和Q路信号构造一个复数函数，生成含有与符号速率相关的离散谱线，通过检测离散谱线的位置实现符号速率的估计。通过MATLAB仿真实验以及在FPGA(field programmable gate array)与DSP(digital signal processor)硬件平台上利用实际信号对算法的性能就行了测试，验证了该方法的有效性。结果表明，该算法复杂度低，运算量小，适应性好，在低信噪比情况下仍具有较高估计精度。同时，该方法所得到的数据也可以用来进行信号识别和其他参数的测量，这在工程实践中具有很高的应用价值。

Symbol rate estimation algorithm for MPSK/MQAM signals

In order to achieve accurate symbol rate estimation in complex environments with low SNR and reduce the complexity and computational burden of the algorithm, a new symbol rate estimation algorithm for MPSK/MQAM signals is proposed. By digitally down converting the A/D sampled signal, a zero-IF signal is obtained, and a complex function is constructed by using the in-phase component and the quadrature component of the zero-IF signal. In the frequency domain, the discrete spectral lines occur at the location corresponding to the symbol rate which can be detected to achieve symbol rate estimation. Both MATLAB simulation and actual signal tests based on the hardware platform of FPGA and DSP verify the effectiveness of the method. The results show that the algorithm has low complexity, low computational burden, good adaptability and high estimation accuracy under low SNR. At the same time, the data obtained by this method can also be used for signal recognition and other parameter estimations, which has a high application value in engineering.