METHOD AND APPARATUS FOR DETERMINING PROPAGATION DELAY

• US 20100081389A1
• Filed: 09/26/2008
• Published: 04/01/2010
• Est. Priority Date: 09/26/2008
• Status: Abandoned Application

• Current Assignee: NXP Laboratories UK Limited (NXP Semiconductors NV)
• Original Assignee: Jennic Ltd. (NXP Semiconductors NV)
• Inventors: LAWROW, Ivan, BATE, Stephen
• Application Number:
  US12/239,322
• Publication Number:
  US 20100081389A1
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: H04L 7/042 Detectors therefor, e.g. correlators, state machines digital correlators in general G06F17/15
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

Embodiments of the present invention provide a method of determining a propagation delay of wireless communications between wireless network devices, comprising exchanging first and second messages with a wireless network device; determining first time information based upon the exchange of the first and second messages; receiving second time information from the wireless network device, the second time information based upon the exchange of the first and second messages; and determining a propagation delay based upon the first and second time information.

Claims

1. A method of determining a propagation delay of wireless communications between wireless network devices, comprising:

exchanging first and second messages with a wireless network device;

determining first time information based upon the exchange of the first and second messages;

receiving second time information from the wireless network device, the second time information based upon the exchange of the first and second messages; and

determining a propagation delay based upon the first and second time information.

2. The method of claim 1, wherein the first time information indicates a time between sending the first message and receiving the second message and the second time information indicates a time between receiving the first message and sending the second message.

3. The method of claim 2, wherein the first and second time information includes a portion of a clock period between the respective events.

4. The method of claim 2, wherein the propagation delay is determined by:

5. The method of claim 1, comprising:

exchanging two further messages with the wireless network device;

determining third time information based upon the exchange of the two further messages;

receiving fourth time information from the wireless network device, the fourth time information based upon the exchange of the two further messages; and

determining a mean propagation delay of the propagation delay of the first and second messages, and a propagation delay of the two further messages based upon the third and fourth time information.

6. The method of claim 5, wherein the third time information indicates a time between receiving a first of the two further messages and transmitting a second of the two further messages and the fourth time information indicates a time between sending the first of the two further message and receiving the second of the two further messages.

7. The method of claim 6, wherein the propagation delay of the two further messages is determined according to the equation:

8. A wireless network device, comprising:

means for wirelessly exchanging first and second messages with another wireless network device; and

means for determining a first time period based upon the exchange of first and second messages; and

means for determining a propagation delay based upon the first time period and information indicative of a second time period received from the other wireless network device.

9. The wireless network device of claim 8, wherein the means for determining the first time period is arranged to determine the first time period between sending the first message and receiving the second message.

10. The wireless network device of claim 9, wherein the means for determining the first time period is arranged to determine the first time period including a fraction of a clock period.

11. The wireless network device of claim 8, wherein the means for determining the propagation delay is arranged to determine the propagation delay according to:

12. The wireless network device of claim 8, comprising:

means for wirelessly exchanging two further messages with the other wireless network device;

means for determining a third time period based upon the exchange of the two further messages; and

means for determining the propagation delay based upon the first time period, the information indicative of the second time period, the third time period and information indicative of a fourth time period received from the other wireless network device.

13. A wireless network, comprising:

a first node arranged to wirelessly exchange first and second communications with a second node;

wherein the first node is arranged to determine first time information based upon the exchange of the first and second communications;

the second node is arranged to determine second time information based upon the first and second communications and to transmit a third communication to the first node containing the second time information; and

the first node is arranged to determine a propagation delay between the first and second nodes according to the first and second time information.

14. The wireless network of claim 13, wherein the first time information indicates a duration between the first node transmitting the first communication and receiving the second communication from the second node and the second time information indicates a duration between the second node receiving the first communication and transmitting the second communication.

15. The wireless network of claim 14, wherein the first node is arranged to determine the first time information including a fraction of a clock cycle between transmitting the first communication and receiving the second communication from the second node.

16. The wireless network of claim 14, wherein the first node is arranged to determine the propagation delay according to the equation:

17. The wireless network of claim 13, wherein:

the first and second nodes are arranged to exchange fourth and fifth communications;

the first node is arranged to determine third time information based upon the exchange of the fourth and fifth communications;

the second node is arranged to determine fourth time information based upon the exchange of the fourth and fifth communications and to transmit a sixth communication to the first node containing the fourth time information;

the first node is arranged to determine a mean propagation delay based upon the first, second, third and fourth time information.

18. The wireless network of claim 17, wherein the third time information indicates a time between the first node receiving the fourth communication and transmitting the fifth communication and the fourth time information indicates a time between the second node transmitting the fourth communication and receiving the fifth communication.

19. The wireless network of claim 18, wherein the first node is arranged to determine a propagation delay of the fourth and fifth communications according to the equation:

20. The wireless network of claim 13, wherein the second node is a mobile node and the first node is arranged to determine a distance to the mobile node according to the propagation delay.