MAC protocol for accurately computing the position of wireless devices inside buildings

• US 20040246986A1
• Filed: 06/04/2004
• Published: 12/09/2004
• Est. Priority Date: 06/06/2003
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: MeshNetworks, Inc. (Motorola Solutions, Inc.)
• Inventors: Belcea, John M.
• Granted Patent: US 7,349,441 B2
• Time in Patent Office: Days
• US Class Current: 370/444
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/52 specially adapted for the location of the user terminal
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A system and method for providing a MAC protocol that allows the collection of a large number of range measurements, and based upon such measurements, permits a very precise computation of the location of terminals at a location. Specifically, the system and method operates with Mobile Terminals, Fixed References and at least one Main Control, wherein a MAC protocol defines the sequence of messages exchanged between each Mobile Terminals, Fixed Reference and the Main Control for assuring the data needed for computing the location is received.

Claims

1. A method for determining the location of wireless terminals of a wireless ad-hoc multi-hopping peer-to-peer network deployed in a three-dimensional multi-level structure, the method comprising:

controlling the terminals to register with a controller of the network;

operating the controller to assign a respective sequence number to each of the terminals; and

controlling the terminals to base their respective time of transmission of a message on their respective sequence number.

2. A method as claimed in claim 1, wherein:

the terminal registration controlling step includes controlling each terminal to transmit a respective registration request message to the controller after receiving a ready to receive registration requests message from the controller.

3. A method as claimed in claim 2, wherein:

the controller operating step includes operating the controller to transmit respective registration acknowledgement messages, each including a respective sequence number of a terminal, to the terminals in response to the respective registration request messages received from the terminals.

4. A method as claimed in claim 3, further comprising:

controlling each of said terminals that are fixed terminals to record a respective corrected arrival time based on its own clock upon receipt of its respective registration acknowledgement message.

5. A method as claimed in claim 4, wherein:

the respective corrected arrival time is based on the arrival time of the respective registration acknowledgement message and an autocorrelation function associated with a modem in the respective terminal.

6. A method as claimed in claim 4, further comprising:

controlling each of said fixed terminals to transmit a respective fixed reference range message to the controller including data representing its respective corrected arrival time.

7. A method as claimed in claim 6, further comprising:

operating the controller to store each respective corrected arrival time data for each respective fixed terminal from which a respective fixed reference range message was received.

8. A method as claimed in claim 2, wherein:

the terminal registration controlling step includes controlling each terminal to transmit its respective registration request message based on a value of a random number generated by a random number generator in the terminal.

9. A method as claimed in claim 2, wherein:

the terminal registration controlling step includes controlling each terminal to transmit its respective registration request message over the same frequency.

10. A method as claimed in claim 1, wherein:

some of the terminals are fixed terminals and some of the terminals are mobile terminals.

11. A computer-readable medium of instructions for determining the location of wireless terminals of a wireless ad-hoc multi-hopping peer-to-peer network deployed in a three-dimensional multi-level structure, the instructions comprising:

a first set of instructions for controlling the terminals to register with a controller of the network;

a second set of instructions for operating the controller to assign a respective sequence number to each of the terminals; and

a third set of instructions for controlling the terminals to base their respective time of transmission of a message on their respective sequence number.

12. A computer-readable medium of instructions as claimed in claim 11, wherein:

the first set of instructions control each terminal to transmit a respective registration request message to the controller after receiving a ready to receive registration requests message from the controller.

13. A computer-readable medium of instructions as claimed in claim 12, wherein:

the second set of instructions operates the controller to transmit respective registration acknowledgement messages, each including a respective sequence number of a terminal, to the terminals in response to the respective registration request messages received from the terminals.

14. A computer-readable medium of instructions as claimed in claim 13, further comprising:

the fourth set of instructions for controlling each of said terminals that are fixed terminals to record a respective corrected arrival time based on its own clock upon receipt of its respective registration acknowledgement message.

15. A computer-readable medium of instructions as claimed in claim 14, wherein:

the respective corrected arrival time is based on the arrival time of the respective registration acknowledgement message and an autocorrelation function associated with a modem in the respective terminal.

16. A computer-readable medium of instructions as claimed in claim 14, further comprising:

a fifth set of instructions for controlling each of said fixed terminals to transmit a respective fixed reference range message to the controller including data representing its respective corrected arrival time.

17. A computer-readable medium of instructions as claimed in claim 16, further comprising:

a sixth set of instructions for operating the controller to store each respective corrected arrival time data for each respective fixed terminal from which a respective fixed reference range message was received.

18. A computer-readable medium of instructions as claimed in claim 12, wherein:

the first set of instructions controls each terminal to transmit its respective registration request message based on a value of a random number generated by a random number generator in the terminal.

19. A computer-readable medium of instructions as claimed in claim 12, wherein:

the first set of instructions controls each terminal to transmit its respective registration request message over the same frequency.

20. A computer-readable medium of instructions as claimed in claim 11, wherein:

some of the terminals are fixed terminals and some of the terminals are mobile terminals.