| CPC H04L 43/0864 (2013.01) [H04L 43/106 (2013.01)] | 20 Claims |

|
1. A method comprising the steps:
a) sending a first communication from a first device to a second device, which first device has a first clock being local to the first device, which second device has a second clock being local to the second device, which first and second devices are both connected for digital communication to a digital communication network, measuring a first communication send time (τ1) using the first clock and measuring a first communication receive time (τ2) using the second clock;
b) sending a second communication from the second device to the first device, measuring a second communication send time (τ3) using the second clock and measuring a second communication receive time (τ4) using the first clock;
c) calculating a first measured delay (y1) as the difference between the first communication receive time (τ2) and the first communication send time (τ1) and calculating a second measured delay (y2) as the difference between the second communication receive time (τ4) and the second communication send time (τ3);
d) providing said first measured delay (y1) and said second measured delay (y2) to a recursive filter function arranged to estimate a first latency (d1) and a second latency (d2) based on said first measured delay (y1), said second measured delay (y2), a value for the first latency (d1) previously estimated by said recursive filter function and a value for the second latency (d2) previously estimated by said recursive filter function; and
e) iterating from step a.
|