Simplified Time Synchronization Method for 5G NR System in High-Frequency Offset Environment.

A simplified time synchronization method for 5G in high-frequency offset environments is proposed, which includes two steps: coarse synchronization and fine synchronization. In the first stage, a method based on FFT window is proposed to find the approximate position of the PSS. Then, in the frequency domain, auto-correlation is used to eliminate the phase rotation on the PSS sub-carriers caused by timing synchronization offset, and then cross correlation is performed with the local pre-stored sequence to determine the PSS sequence. In the second stage, due the known PSS sequence, a sliding cross correlation method based on frequency offset pre-compensation is used to achieve precise synchronization in a limited area adjacent to the coarse synchronization position.Simulation results show that the proposed method has good robustness in high-frequency offset environment and significantly reduces complexity compared to existing popular methods. This method is not only applicable to 5G system, but also serves as a reference for improving the synchronization performance of other wireless systems with high linear frequency offset caused by crystal oscillators deviation or high mobility.