System and method for time synchronization in a communication network

A method for time synchronization in a communication network, the communication network comprising a plurality of network nodes each having a respective internal clock, and a reference node having a reference clock and configured for transmitting synchronization messages within the communication network, at least one network node being configured to determine an estimated reference clock time discretely upon arrival of a synchronization message at the at least one network node, the method comprising:

• configuring, for the at least one network node, a controller for determining a controlled time comprising a time-continuous estimate of the discretely estimated reference clock time based on an input extrapolated to an execution time instant of the controller, the extrapolation being performed based on a slope of the estimated reference clock time and a slope of the controlled time with respect to an internal clock time of the at least one network node, the execution time instant being separated from an arrival time instant of the synchronization message by a delay (Δtdelay);
• and
• determining the input as an offset between the discretely estimated reference clock time and the controlled time, extrapolated to said execution time instant;
• wherein the reference node and each of the plurality of network nodes communicating sequentially with each other.

A network node included in a system for time synchronization in a communication network, the network node comprising:

• an internal clock;
• and
• a controller configured to determine a controlled time comprising a time-continuous estimate of an estimated reference clock time, the controller being configured to determine the controlled time based on an input which is extrapolated to an execution time instant of the controller, the extrapolation being performed based on a slope of the estimated reference clock time and a slope of the controlled time with respect to an internal clock time of the at least one network node, and the execution time instant being separated from an arrival time instant of the synchronization message by a delay (Δtdelay);
• wherein the network node is configured to determine the estimated reference clock time discretely upon arrival of the synchronization message and configured to communicate sequentially with other nodes.

A network node having a controller and an internal clock for time synchronization in a communication network;

• wherein the network node is configured to:
• determine an estimated reference clock time discretely upon arrival of a synchronization message;
• configure the controller to determine a controlled time comprising a time-continuous estimate of the discretely estimated reference clock time based on an input extrapolated to an execution time instant of the controller, the extrapolation being performed based on a slope of the estimated reference clock time and a slope of the controlled time with respect to an internal clock time of the at least one network node, and the execution time instant being separated from an arrival time instant of the synchronization message by a delay (Δtdelay);
• determine the input as an offset between the discretely estimated reference clock time and the controlled time, extrapolated to said execution time instant;
• and
• communicate sequentially with other nodes.

A computer program product executing on a processor which, when used on a non-transitory computer readable media having computer readable program code embodied therein which, when used on a computer apparatus, causes the processor to perform time synchronization in a communication network, the computer program comprising:

• program code for configuring, for at least one network node, a controller for determining a controlled time comprising a time-continuous estimate of a discretely estimated reference clock time based on an input extrapolated to an execution time instant of the controller, the extrapolation being performed based on a slope of the estimated reference clock time and a slope of the controlled time with respect to an internal clock time of the at least one network node, and the execution time instant being separated from an arrival time instant of a synchronization message by a delay (Δtdelay);
• program code for determining the input as an offset between the discretely estimated reference clock time and the controlled time, extrapolated to said execution time instant;
• and
• program code for communicating sequentially with other nodes.