基于盲源分离的载波残余频偏相偏盲估计

Blind source separation-based blind estimation of carrier residual frequency and phase offset

在分析频偏对信号星座图影响的基础上,提出了一种基于盲源分离的载波残余频偏与相偏的估计方法。首先对接收信号进行中心化和白化的预处理,且用以随机数初始化的分离矩阵对接收的数据点进行实时分离处理;然后结合随机梯度算法对分离矩阵、混合矩阵以及全局矩阵进行估计,并用基于全局矩阵估计的PI值对变步长进行更新;最后根据分离矩阵中各元素间的关系估计出残余频偏信号的相位变化轨迹,即可进一步由相邻相位突跳点间的间隔数估计出载波频偏的大小。仿真结果表明,该方法能有效地估计出接收信号的残余频偏与固定相偏值。

On the basis of analyzing the effects of frequency offset on signal constellation, a blind source separation-based carrier residual frequency and phase offset estimation method is proposed. The received signals are first centered and whitened, and the received data points are separated in time by using the initiated separation matrix with random numbers. Then, the separa- tion-, mixed- and global matrixes are estimated using the stochastic gradient algorithm and the variable step size are updated with the PI value estimated on the basis of the global matrix estimation. Finally, the phase change trajectory of the residual fre- quency offset signals can be estimated on the basis of the relationship between various elements in the separation matrix and consequently the carrier frequency offset size can be estimated from the number of intervals between the adjacent phase jumping points. Simulation results show that this method can effectively estimate the residual carrier frequency offset and stationary phase offset values of the received signals.