Method and apparatus for using ranging measurements in a multimedia home network

• US 8,363,681 B2
• Filed: 10/15/2009
• Issued: 01/29/2013
• Est. Priority Date: 10/16/2008
• Status: Active Grant

• Current Assignee: Entropic Communications, LLC (SoftBank Group Corp.)
• Original Assignee: Entropic Communications Incorporated (Maxlinear Incorporated)
• Inventors: Mueller, Arndt
• Primary Examiner(s): Thier, Michael
• Assistant Examiner(s): Elliott, IV, Benjamin H
• Application Number:
  US12/580,127
• Publication Number:
  US 20100098110A1
• Time in Patent Office: 1,202 Days
• Field of Search: 370/395.62, 370/518, 370/350, 370/503, 370509-514, 370/519
• US Class Current: 370/509
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04L 41/147 for predicting network behaviour
• CPC Class Codes: H04L 41/149 for prediction of maintenance
• CPC Class Codes: H04L 43/0852 Delays

Abstract

According to various embodiments of the disclosure, systems, methods and apparatuses are provided for using ranging to improve network efficiency. In particular, various embodiments of the disclosure provide ranging to improve local clock time synchronization. According to one embodiment, a method for synchronizing a plurality of nodes on a communication network is provided, comprising: exchanging local clock times between a first node and a second node over the communication network; performing a ranging method between the first and second nodes based on the local clock times exchanged between the first and second nodes, wherein the ranging method results in an estimated propagation delay between the first and second nodes; and adjusting the local clock times of the first and second nodes based on the estimated propagation delay, thereby resulting in a synchronized local clock time at the first and second nodes.

Claims

1. A method for synchronizing a plurality of nodes on a communication network, comprising:

exchanging a local clock time between a first node and a second node over the communication network, wherein the exchange comprises;

transmitting a first packet from the first node to the second node, wherein the first packet includes a first packet clock time set to the local clock time of the first node at transmission time, and includes a scheduled arrival clock time, and

setting the local clock time of the second node to the first packet clock time;

performing a ranging method between the first and second nodes based on the local clock time exchanged, wherein the ranging method results in an estimated propagation delay between the first and second node, and wherein the ranging method comprises;

transmitting a second packet from the second node to the first node, wherein the second packet is transmitted from the second node at the scheduled arrival clock time, and wherein the second packet is received by the first node at an actual arrival clock time,

calculating and storing the estimated propagation delay at the first node, wherein calculating the estimated propagation delay is based on the scheduled arrival clock time and the actual arrival time, and

transmitting a third packet from the first node to the second node, wherein the third packet comprises the estimated propagation delay; and

adjusting the local clock time of either the first or second node based on the estimated propagation delay, thereby resulting in a synchronized local clock time between the first and second node.

2. The method of claim 1, further comprising using the synchronized local clock time in subsequent packet transmissions between the first and second nodes.

3. The method of claim 1, wherein adjusting the local clock times comprises storing the estimated propagation delay at the second node.

4. The method of claim 1, wherein a transmission time of a transmitted packet is measured at 90% of peak amplitude of a transmission signal, 90% of peak power of a transmission signal, 90% of total power of a transmission signal, or a mean delay of a transmission signal.

5. The method of claim 1, wherein an arrival time of a received packet is measured at 90% of peak amplitude of a received signal, 90% of peak power of a received signal, 90% of total power of a received signal, or a mean delay of a received signal.

6. The method of claim 1, wherein the first node is a network coordinator.

7. The method of claim 1, wherein the second node is a new node and the method is performed as part of admission of the second node to the communication network.

8. The method of claim 1, wherein the method is performed periodically to maintain synchronization between the first and second nodes.

9. The method of claim 1, wherein the communication network is a mesh network.

10. The method of claim 1, wherein the communication network operates in accordance with a Multimedia over Coax Alliance (MoCA) standard.

11. A network device, comprising:

a controller;

a device module;

memory coupled to the controller;

computer executable program code on a non-transitory computer readable medium configured to cause the controller to perform the functions of;

exchanging local clock times between a first node and a second node over a communication network, wherein the exchange comprises;

transmitting a first packet from the first node to the second node, wherein the first packet includes a first packet clock time set to the local clock time of the first node at transmission time, and includes a scheduled arrival clock time, and

setting the local clock time of the second node to the first packet clock time;

performing a ranging method between the first and second nodes based on the local clock times exchanged between the first and second nodes, wherein the ranging method results in an estimated propagation delay between the first and second nodes, and wherein the ranging method comprises;

transmitting a second packet from the second node to the first node, wherein the second packet is transmitted from the second node at the scheduled arrival clock time, and wherein the second packet is received by the first node at an actual arrival clock time,

calculating and storing the estimated propagation delay at the first node, wherein calculating the estimated propagation delay is based on the scheduled arrival clock time and the actual arrival time, and

transmitting a third packet from the first node to the second node, wherein the third packet comprises the estimated propagation delay; and

adjusting the local clock times of either the first and second nodes based on the estimated propagation delay, thereby resulting in a synchronized local clock time at the first and second nodes.

12. The network device of claim 11, wherein the computer executable program code is further configured to cause the controller to use the synchronized local clock time in subsequent packet transmissions between the first and second nodes.

13. The network device of claim 11, wherein adjusting the local clock times comprises storing the estimated propagation delay at the second node.

14. The network device of claim 11, wherein a transmission time of a transmitted packet is measured at 90% of peak amplitude of a transmission signal, 90% of peak power of a transmission signal, 90% of total power of a transmission signal, or a mean delay of a transmission signal.

15. The network device of claim 11, wherein an arrival time of a received packet is measured at 90% of peak amplitude of a received signal, 90% of peak power of a received signal, 90% of total power of a received signal, or a mean delay of a received signal.

16. The network device of claim 11, wherein the first node is a network coordinator.

17. The network device of claim 11, wherein the second node is a new node and the functions are performed as part of admission of the second node to the communication network.

18. The network device of claim 11, wherein the functions of exchanging local clock times, performing the ranging method, and adjusting the local clock times are performed periodically to maintain synchronization between the first and second nodes.

19. The network device of claim 11, wherein the communication network is a mesh network.

20. The network device of claim 11, wherein the communication network operates in accordance with a Multimedia over Coax Alliance (MoCA) standard.

21. A computer program product comprising a non-transitory computer usable medium having computer readable program code embodied therein for synchronizing a plurality of nodes on a communication network, the compute program product comprising computer readable program code configured to cause a device to:

exchange local clock times between a first node and a second node over a communication network, wherein the exchange comprises;

transmitting a first packet from the first node to the second node, wherein the first packet includes a first packet clock time set to the local clock time of the first node at transmission time, and includes a scheduled arrival clock time, and

setting the local clock time of the second node to the first packet clock time;

perform a ranging method between the first and second nodes based on the local clock times exchanged between the first and second nodes, wherein the ranging method results in an estimated propagation delay between the first and second nodes, and wherein the ranging method comprises;

transmitting a second packet from the second node to the first node, wherein the second packet is transmitted from the second node at the scheduled arrival clock time, and wherein the second packet is received by the first node at an actual arrival clock time,

calculating and storing the estimated propagation delay at the first node, wherein calculating the estimated propagation delay is based on the scheduled arrival clock time and the actual arrival time, and

transmitting a third packet from the first node to the second node, wherein the third packet comprises the estimated propagation delay; and

adjust the local clock times of either the first and second nodes based on the estimated propagation delay, thereby resulting in a synchronized local clock time at the first and second nodes.

22. The computer program product of claim 21, wherein the computer executable program code is further configured to cause the device to use the synchronized local clock time in subsequent packet transmissions between the first and second nodes.

23. The computer program product of claim 21, wherein adjusting the local clock times comprises storing the estimated propagation delay at the second node.

24. The computer program product of claim 21, wherein a transmission time of a transmitted packet is measured at 90% of peak amplitude of a transmission signal, 90% of peak power of a transmission signal, 90% of total power of a transmission signal, or a mean delay of a transmission signal.

25. The computer program product of claim 21, wherein an arrival time of a received packet is measured at 90% of peak amplitude of a received signal, 90% of peak power of a received signal, 90% of total power of a received signal, or a mean delay of a received signal.

26. The computer program product of claim 21, wherein the first node is a network coordinator.

27. The computer program product of claim 21, wherein the second node is a new node and the functions are performed as part of admission of the second node to the communication network.

28. The computer program product of claim 21, wherein the functions of exchanging local clock times, performing the ranging method, and adjusting the local clock times are performed periodically to maintain synchronization between the first and second nodes.

29. The computer program product of claim 21, wherein the communication network is a mesh network.

30. The computer program product of claim 21, wherein the communication network operates in accordance with a Multimedia over Coax Alliance (MoCA) standard.

31. A network interface module, comprising:

a controller;

memory coupled to the controller;

computer executable program code on a non-transitory computer readable medium configured to cause the controller to perform the functions of;

exchanging local clock times between a first node and a second node over a network, wherein the exchange comprises;

transmitting a first packet from the first node to the second node, wherein the first packet includes a first packet clock time set to the local clock time of the first node at transmission time, and includes a scheduled arrival clock time, and

setting the local clock time of the second node to the first packet clock time;

performing a ranging method between the first and second nodes based on the local clock times exchanged between the first and second nodes, wherein the ranging method results in an estimated propagation delay between the first and second nodes, and wherein the ranging method comprises;

transmitting a second packet from the second node to the first node, wherein the second packet is transmitted from the second node at the scheduled arrival clock time, and wherein the second packet is received by the first node at an actual arrival clock time,

calculating and storing the estimated propagation delay at the first node, wherein calculating the estimated propagation delay is based on the scheduled arrival clock time and the actual arrival time, and

transmitting a third packet from the first node to the second node, wherein the third packet comprises the estimated propagation delay; and

adjusting the local clock times of either the first and second nodes based on the estimated propagation delay, thereby resulting in a synchronized local clock time at the first and second nodes.

32. The network interface module of claim 31, wherein the computer executable program code is further configured to cause the controller to use the synchronized local clock time in subsequent packet transmissions between the first and second nodes.

33. The network interface module of claim 31, wherein adjusting the local clock times comprises storing the estimated propagation delay the second node.

34. The network interface module of claim 31, wherein a transmission time of a transmitted packet is measured at 90% of peak amplitude of a transmission signal, 90% of peak power of a transmission signal, 90% of total power of a transmission signal, or a mean delay of a transmission signal.

35. The network interface module of claim 31, wherein an arrival time of a received packet is measured at 90% of peak amplitude of a received signal, 90% of peak power of a received signal, 90% of total power of a received signal, or a mean delay of a received signal.

36. The network interface module of claim 31, wherein the first node is a network coordinator.

37. The network interface module of claim 31, wherein the second node is a new node and the functions are performed as part of admission of the second node to the communication network.

38. The network interface module of claim 31, wherein the functions of exchanging local clock times, performing the ranging method, and adjusting the local clock times are performed periodically to maintain synchronization between the first and second nodes.

39. The network interface module of claim 31, wherein the communication network is a mesh network.

40. The network interface module of claim 31, wherein the communication network operates in accordance with a Multimedia over Coax Alliance (MoCA) standard.