Method and a device for maintaining a synchronized local timer using a periodic signal

摘要

A method is provided for maintaining a synchronized local timer by using a periodic signal which comprises: providing a value of a clock cycle, and values for a first and second timer-parameters, wherein the first timer-parameter is less than the clock cycle value and the second timer-parameter is higher therefrom; providing values for a first (“a”) and second (“b”) arbitration parameters associated with the first and second timer-parameters respectively; upon receiving a periodic signal, adding to the local timer, at least once the first and/or the second timer-parameter, so that on average over one second, the first timer-parameter is added “a” times and the second timer-parameter is added “b” times, thereby ensuring that a value of the local timer essentially overlaps the period frequency of the periodic signal; upon receiving a subsequent periodic signal, setting the value of the local timer to a propagation delay of the periodic signal.

主权项

1. A method for maintaining a synchronized local timer in a network element by using a periodic signal having a known period frequency, the method comprising:
providing a value of a clock cycle associated with the network element, and values for a first timer-parameter (“T−”) and a second timer-parameter (“T+”), wherein the value of the first timer-parameter T− is lower than the value of the clock cycle and the value of the second timer-parameter T+ is higher than the value of the clock cycle; providing values for a first arbitration parameter (“a”) associated with the first timer-parameter and a second arbitration parameter (“b”) associated with the second timer-parameter; in response to receiving a periodic signal, adding every clock cycle to the local timer of the network element, at least once the first timer-parameter (T−) and/or at least once the second timer-parameter (T+), wherein said addition is made so that on average over one second, the first timer-parameter is added “a” times and the second timer-parameter is added “b” times, thereby ensuring that a value of the local timer essentially overlaps the period frequency of the periodic signal; and in response to receiving a subsequent periodic signal, setting the value of the local timer to a propagation delay of the periodic signal, for maintaining the value of the local timer substantially synchronized with a master unit.