Method and apparatus for calculating transmission delay across a network

摘要

A method of calculating a transmission delay value for data transmitted from a first device to a second device across a communications link. The method involves calculating a plurality of measured values representing the transmission delay measured by the second device over time; detecting a minimum boundary of the measured values; and deriving the transmission delay value from the minimum boundary. The transmission delay value may be used to synchronize the clock signal of the second device to the clock signal of the first device.

主权项

1. A method of calculating a transmission delay value for data transmitted from a first device to a second device across a communications link, the method comprising:
calculating, by a processor, a plurality of measured values representing the transmission delay value measured by the second device over time; detecting, by the processor, a boundary of the plurality of measured values by determining a plurality of boundary values including a sub-set of the plurality of measured values by:
calculating a first rate of change between a first measured value taken at a first time and a second measured value taken at a second time preceding the first time,calculating a second rate of change between the second measured value and a third measured value taken at a third time preceding the second time,comparing the first and second rates of change, andexcluding the second measured value from or including the second measured value in the sub-set depending on the comparison of the first and second rates of change, wherein the boundary comprises at least one of the plurality of boundary values; and deriving, by the processor, the transmission delay value from the at least one of the plurality of boundary values, wherein detecting the boundary involves updating a parameter value in respect of each of the plurality of measured values, wherein updating the parameter value involves setting the parameter value to the lower one of: a current measurement time; and the parameter value modified by application of a mathematical function.