论文部分内容阅读
针对在任意阶正交幅度调制(M-QAM)的相干光通信系统中发射激光器与本振激光器之间存在频率偏差的问题,提出了一种基于幅度比值的低复杂度频偏估计算法。该算法先对接收信号做快速傅里叶变换(FFT),再利用所获得的离散谱中主峰值与次峰值的关系进行频率插值,从而对频偏进行精确估计,大幅减少了运算复杂度。仿真了算法在20 Gbaud 16QAM的单偏振传输系统中的性能,并与梯度下降法(GD)和调频Z变换(CZT)的频偏估计算法进行了对比,仿真结果显示,基于幅度比值的频偏估计算法性能不随被估计信号的频率分布而产生波动,而且与3次迭代的GD算法和CZT算法精度相当,但硬件复杂度降低了约75%。
Aiming at the problem of frequency deviation between transmitting laser and local laser in coherent optical communication system with arbitrary order quadrature amplitude modulation (M-QAM), a low complexity frequency offset estimation algorithm based on amplitude ratio is proposed. The algorithm first performs fast Fourier transform (FFT) on the received signal and then uses the relationship between the main peak and the second peak in the discrete spectrum to perform frequency interpolation to accurately estimate the frequency offset, thereby greatly reducing the computational complexity. The performance of the algorithm in a single polarization transmission system of 20 Gbaud 16QAM is simulated and compared with the frequency offset estimation algorithm of gradient descent method (GD) and frequency modulation Z transform (CZT). The simulation results show that the frequency deviation based on amplitude ratio The performance of the estimation algorithm does not fluctuate with the frequency distribution of the estimated signal, and it is equivalent to the GD algorithm and CZT algorithm of 3 iterations, but the hardware complexity is reduced by about 75%.