公开(公告)号：US20190260490A1

公开(公告)日：2019-08-22

申请号：US16401996

申请日：2019-05-02

Applicant: Huawei Technologies Co., Ltd.

Inventor： Jingfei Lv ,  Jinhui Wang ,  Chuan Xu

IPC: H04J3/06

Abstract: A frequency synchronization method includes: receiving, by a slave clock, a first pulse signal and a second pulse signal; determining, by the slave clock based on a first phase difference, a second phase difference, a first delay, and a second delay, that a frequency offset of the slave clock relative to the master clock is equal to a first frequency offset, where the first phase difference is a difference between a phase of a third pulse signal generated by the slave clock and a phase of the first pulse signal received by the slave clock, and the second phase difference is a difference between a phase of a fourth pulse signal generated by the slave clock and a phase of the second pulse signal received by the slave clock; and calibrating, by the slave clock, frequency of the slave clock based on the first frequency offset.

公开(公告)号：US20180049147A1

公开(公告)日：2018-02-15

申请号：US15794904

申请日：2017-10-26

Applicant: Huawei Technologies Co., Ltd.

Inventor： Cong Chen ,  Chuan Xu

IPC: H04W56/00 ,  H04J3/06

CPC classification number: H04W56/0015 ,  H04J3/0644 ,  H04J3/0661 ,  H04J3/0682 ,  H04W56/00 ,  H04W72/0406 ,  H04W88/08 ,  H04W88/085

Abstract: A time synchronization method and system, and a network device, where the method includes receiving, by a second network device, a first packet from a first network device, where the first packet includes a first service frame and a first time stamp (T1), the first service frame carries a system clock of a radio equipment control (REC), obtaining, the system clock of the REC according to the first packet, sending, according to the system clock of the REC, the first service frame extracted from the first packet to a radio equipment (RE), recording a second time stamp (T2) at which the first service frame is sent, and determining, by the second network device, a transmission delay (T) according to T=T2−T1. Hence, a delay between the REC and the RE remains unchanged.