Sub-Frame Synchronized Residual Ranging

• US 20080056308A1
• Filed: 08/30/2006
• Published: 03/06/2008
• Est. Priority Date: 08/30/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Zumsteg, Philip J.
• Granted Patent: US 7,688,747 B2
• Time in Patent Office: Days
• US Class Current: 370/503
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method of ranging between nodes is provided. The method includes synchronizing two or more nodes with a frame preamble. Exchanging data and ranging schedule between the nodes without an additional frame preamble. Starting a schedule clock in each node in response to a switch point and exchanging one or more range signals between nodes based on the ranging schedule.

Claims

1. A method of ranging between nodes, the method comprising:

synchronizing two or more nodes with a frame preamble;

exchanging data and ranging schedule between the nodes without an additional frame preamble;

starting a schedule clock in each node in response to a switch point; and

exchanging one or more range signals between nodes based on the ranging schedule.

2. The method of claim 1, further comprising:

periodically checking the ranging schedule in a node.

3. The method of claim 2, further comprising:

determining if the node is scheduled to receive.

4. The method of claim 3, further comprising:

when the node is scheduled to receive, starting a range timer.

5. The method of claim 4, further comprising:

determining if the node received one or more ranging signals.

6. The method of claim 5, further comprising:

when the node received range data, stopping the range timer and storing the range timer value.

7. The method of claim 5, further comprising:

when the node did not receive range data, determining if the range timer has reached it maximum value.

8. The method of claim 7, further comprising:

when the range timer has reached its maximum value without receiving range data, stopping range timer and flagging the timer reached a maximum value.

9. The method of claim of claim 2, further comprising:

when the node is not scheduled to receive range data, determining if the node is scheduled to transmit range data.

10. The method of claim 9, further comprising:

when it is determined that the node is scheduled to transmit one or more ranging signals, changing the node to a transmit mode; and

transmitting ranging signals.

11. The method of claim 9, further comprising:

when is determined the node is not scheduled to transmit range data, determining if the schedule is at the end of the ranging application.

12. A method of communication with a node, the method comprising:

synchronizing communication with at least one other node with a frame preamble,

exchanging data in a frame between the node and the at least one other node without an additional frame preamble, the exchanged data including a ranging schedule;

entering into a ranging mode upon detection of a special switch point;

implementing a schedule timer when the node is scheduled to receive a range signal; and

transmitting range data when scheduled to transmit.

13. The method of claim 12, further comprising:

implementing a start clock upon entering into the ranging mode.

14. The method of claim 12, wherein implementing a range timer when the node is scheduled to receive a range pulse further comprises:

determining if the node received range data within a select time period tracked by the range timer; and

indicating when the node did not receive the range data within the select time period.

15. The method of claim 13, further comprising:

determining if the node is to end the ranging mode based on the schedule; and

when the node is not scheduled to end the ranging mode, updating the start clock.

16. A communication node comprising:

a transmitter/receiver circuit adapted to selectively transmit and receive communication signals;

a synchronization circuit adapted to synchronize the local clock with a received communication signal from at least one other communication node to establish communications between the communication nodes; and

a control circuit adapted to control the transmitter/receiver circuit and the synchronization circuit, the control circuit being adapted to process communication signals, the control circuit further adapted to direct communications between the communication nodes without re-synchronizing the local clock for a period of time, the control circuit further adapted to enter into a ranging mode and implement a ranging schedule in response to a special switch point;

a start clock adapted to clock scheduling operations of the communication node when the communication node enters into the ranging mode; and

a range timer adapted to track a time period when the node is scheduled to receive range data.

17. The communication node of claim 16, wherein the control circuit is further adapted to flag time periods in which the node does not receive ranging data pursuant to the schedule.

18. The communication node of claim 16, wherein the synchronization circuit is further adapted to resynchronize communication between the nodes upon completion of the ranging mode pursuant to the ranging schedule.

19. The communication node of claim 16, wherein the control circuit is further adapted to update the start clock pursuant to ranging schedule.

20. The communication node of claim 16, wherein the control circuit is further adapted to direct the transmitter to transmit range information pursuant to the ranging schedule.