A Parallel-Enabled Frequency Offset Estimation Scheme for Optical Coherent Receivers

Abstract

PADE, a digital frequency offset (FO) estimator for optical coherent receivers, is accurate and has a wide stable-running estimation range. But its operation requires making estimation in one symbol period. For very high-speed demand of optical transmission system, this would be difficult to realize with the existing hardware. In order to solve the problem, we propose an FO estimator scheme in which PADE can be operated group by group, where a group stands for a group of consecutive symbols. This grouping mechanism would make parallel operation possible for FO estimation, and reduce the hardware speed requirement. At the same time, the average calculation complexity for each symbol becomes much lower. Considering of practice, we give an initialization scheme for the new estimator. The simulation results show that, with feasible group length, the new FO estimator is effective and have the same performance as PADE.