Method and system for time synchronization
First Claim
1. A method of synchronizing a timing device of a client station comprising the steps of:
- a) sending a plurality of packets, each packet being sent at a predetermined time having a predetermined temporal spacing from other packets, from a time server to the client station via a communications network;
b) receiving the plurality of packets at the client station;
c) determining a time indicative of a local time of receipt of the plurality of packets at the client station and storing time data in dependence thereon;
d) returning the plurality of packets to the time server via the communications network;
e) determining a time indicative of a local time of receipt of the plurality of packets at the time server; and
, f) determining synchronisation data in dependence upon round trip delay of the packets and variance in temporal spacing of received packets.
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Accused Products
Abstract
A method for synchronizing a timing device of a client station via a communications network is disclosed. A plurality of packets is sent from a time server to the client station via the communications network. Upon receipt of the plurality of packets at the client station a time indicative of a local time of receipt of the plurality of packets is determined and the plurality of packets are returned to the time server via the communications network. Upon receipt of the plurality of packets at the time server data in dependence upon round trip delay of the packets and variance in packet spacing are determined and compared to threshold values. If the determined data are within the threshold values data indicative of a time correction are determined and sent from the time server to the client station.
51 Citations
33 Claims
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1. A method of synchronizing a timing device of a client station comprising the steps of:
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a) sending a plurality of packets, each packet being sent at a predetermined time having a predetermined temporal spacing from other packets, from a time server to the client station via a communications network;
b) receiving the plurality of packets at the client station;
c) determining a time indicative of a local time of receipt of the plurality of packets at the client station and storing time data in dependence thereon;
d) returning the plurality of packets to the time server via the communications network;
e) determining a time indicative of a local time of receipt of the plurality of packets at the time server; and
,f) determining synchronisation data in dependence upon round trip delay of the packets and variance in temporal spacing of received packets. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of synchronizing a timing device coupled to a communications network comprising the steps of:
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a) sending a plurality of packets, each packet being sent at a predetermined time, from a first node to a second node via a communications network;
b) receiving the plurality of packets at the second node;
c) determining a time indicative of a local time of receipt of the plurality of packets and providing time data in dependence thereon;
d) returning the plurality of packets to the first node via the communications network;
e) determining a time indicative of a local time of receipt of the plurality of packets at the first node; and
,f) determining data in dependence upon round trip delay of the packets and variance in packet spacing and comparing the data to threshold values. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A system of synchronizing a timing device of a client station via a communications network comprising:
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first processing means connected to the communications network and a time clock; and
, second processing means connected to the communications network and the timing device,wherein the first processing means comprise;
means for sending in real time a plurality of packets, each packet being sent at a predetermined time, via the communications network to second processing means;
means for receiving the plurality of packets from the second processing means in real time;
means for determining in real time a time indicative of a time of receipt of each of the plurality of packets;
means for determining data in dependence upon round trip delay of the packets and variance in packet temporal spacing and comparing the data to threshold values;
means for determining data indicative of a correct time in dependence upon time data from the time clock and the data in dependence upon round trip delay of the packets and variance in packet temporal spacing; and
,means for sending a signal comprising the data indicative of a time correction to the second processing means via the communications network; and
,wherein the second processing means comprise;
means for receiving a plurality of packets from the first processing means in real time;
means for determining in real time a time indicative of a time of receipt of each of the plurality of packets;
means for returning the plurality of packets in real time to the first processing means;
means for receiving a signal comprising the data indicative of a time correction from the first processing means; and
,means for synchronizing the timing device in dependence upon the data indicative of the time correction. - View Dependent Claims (30, 31, 32, 33)
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Specification