A Fast Frequency Offset Acquisition Method for High-Order QAM

A new joint carrier recovery structure is designed for the carrier recovery of high-order QAM signals. Under the IFOE and PFD modules, this structure adopts the method of multi-threshold instead of single threshold to improve the frequency offset acquisition speed, and adds a screening mechanism to eliminate the estimation value with large error in the IFOE algorithm, which improves the accuracy of the IFOE algorithm at low SNR. From the simulation results of each algorithms under 64-QAM signals, the proposed algorithm has obvious advantages at low SNR and is least affected by frequency offset, It can achieve fast frequency offset acquisition and low steady-state error under the condition of large frequency offset.