一种高效的APSK调制信号载波频偏估计算法

An efficient algorithm for estimating carrier frequency offset of APSK modulated signal

摘要:

提出一种有效的幅度相位键控(APSK)调制信号载波频偏估计算法。该算法针对定时同步后的信号数据，根据APSK调制信号星座图数据点幅度半径不同的特点，将星座图上幅度半径最小的数据点保留，其余幅度半径较大的数据点的值均置零。对置零处理后的数据进行4次方谱线提取，从而估计信号的载波频偏。仿真试验表明该算法计算复杂度低, 具有很强的实用性。当数据量为500，信噪比大于15 dB时，频偏估计均方误差低于-80 dB。

Abstract:

An effective algorithm is presented for estimating carrier frequency offset of Amplitude Phase Shift Keying(APSK) modulated signal. The data of the signal is obtained after the process of timing synchronization. The algorithm is based on the characteristic that the radiuses of the points of the constellation of APSK modulated signal are different. The value of the data is set to zero except the points with the smallest radius. The spectrum line of the quartic spectrum of the zeroing data is extracted to estimate carrier frequency offset. Simulation results show that this algorithm has low complexity and high practicality. The mean square error of the estimation of carrier frequency offset is below -80 dB when the number of symbol is 500 and the signal to noise ratio is above 15 dB.