Patent ID: 9344981
Filing Date: 2016-05-17
CPC Classification: H04J,H04W

Claim Text:
1. A method for synchronizing clocks comprising: (a) a master element of a network sending a first sync message to a first slave element, the first sync message having information identifying a first time, the first time being a time of a clock of the master element at which the first sync message was sent by the master element; (b) the first slave element of the network receiving the first sync message at a second time, the second time being a time of a clock of the first slave element at which the first sync message was received by the first slave element; (c) in response to receiving the first sync message, the first slave element sending a first line delay request message to the master element at a third time, the third time being a time of the clock of the first slave element at which the first line delay request message is sent to the master element; (d) the master element receiving the first line delay request message at a fourth time, the fourth time being a time of the clock of the master element at which the first line delay request message is received by the master element; (e) in response to receiving the first line delay request message, the master element sending a first line delay response message having information identifying the fourth time to the slave element; and (f) the slave element receiving the first line delay response message such that the slave element knows the first time, the second time, the third time, and the fourth time; and (g) the slave element calculating a line delay based on the first, second, third and fourth times; (h) prior to the slave element calculating the line delay, determining that the first sync message is acceptable for use in synchronizing the clock of the slave element by determining that a difference between the first time and the second time is at or below a first threshold; and (i) prior to the slave element calculating the line delay, determining the first line delay request message is acceptable for use in synchronizing the clock of the slave element by determining that a difference between the third time and the fourth time is at or below a second threshold; and wherein one of: