System and method for mobile location detection in synchronous wireless systems

• US 6,539,229 B1
• Filed: 08/20/1999
• Issued: 03/25/2003
• Est. Priority Date: 08/20/1998
• Status: Expired due to Term

• Current Assignee: Ironworks Patents LLC, Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Ali, Farhan
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): PERSINO, RAYMOND B
• Application Number:
  US09/372,153
• Time in Patent Office: 1,313 Days
• Field of Search: 455/456, 342/450, 342/463, 342/464, 342/457, 342/387, 340/988
• US Class Current: 455/456.1
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A system and method for determining the geographic location of a mobile station in a mobile telephone system is disclosed. The system broadcasts a series of forward link triangulation signals from an array of base transceiver stations, so that a mobile station may determine the differential times of arrival, and thereby the mobile station'"'"'s location.

Claims

1. A method for determining the geographic location of a mobile station in a mobile telephone system, comprising:

receiving a plurality of forward link triangulation signals at said mobile station, wherein said plurality of forward link triangulation signals are received with increased transmitted power occurs during a duty cycle;

timestamping said forward link triangulation signals within said mobile station;

calculating a first hyperbola and a second hyperbola from said timestamped forward link triangulation signals; and

calculating the intersection of said first hyperbola and said second hyperbola.

2. The method of claim 1, wherein said receiving is continuously or periodically.

3. The method of claim 1, wherein said increased transmitted power includes adjusting said duty cycle such that average transmitted power is limited to a predetermined level.

4. The method of claim 1, wherein said timestamping includes calculating differential time of arrival values.

5. The method of claim 4, wherein said calculating said first hyperbola and said second hyperbola utilizes said differential time of arrival values.

6. The method of claim 1, further comprising broadcasting said plurality of forward link triangulation signals from a plurality of base transceiver stations.

7. The method of claim 6, wherein said increased transmitted power is provided at the plurality of base transceiver stations.

8. The method of claim 6, wherein said broadcasting is synchronized by a time standard.

9. The method of claim 8, wherein said time standard is set by a global positioning system.

10. A system for determining the geographic location of a mobile station in a mobile telephone system, comprising:

a plurality of forward link triangulation signals received at said mobile station, wherein said forward link triangulation signals are received with increased transmitted power during a duty cycle;

a receiver configured to couple a plurality of timestamped values to said forward link triangulation signals within said mobile station;

a first processor configured to calculate a first hyperbola and a second hyperbola from said timestamped values coupled to said forward link triangulation signals; and

a second processor configured to calculate an intersection point of said first hyperbola and said second hyperbola.

11. The system of claim 10, wherein said forward link triangulation signals are received continuously or periodically.

12. The system of claim 10, wherein said duty cycle is adjustable such that average transmitted power is limited to a predetermined level.

13. The system of claim 10, wherein said forward link triangulation signals are broadcast from a plurality of base transceiver stations.

14. The system of claim 13, wherein said increased transmitted power is provided at the plurality of base transceiver stations.

15. The system of claim 10, wherein said receiver couples differential time of arrival values to said forward link triangulation signals.

16. The system of claim 15, wherein said first processor utilizes said differential time of arrival values.

17. The system of claim 10, wherein said base transceiver stations are synchronized by a time standard.

18. The system of claim 17, wherein said time standard is set by a global positioning system.

19. A machine-readable medium having stored thereon executable code which causes a machine to perform a method, for determining the geographic location of a mobile station in a mobile telephone system, the method comprising:

receiving a plurality of forward link triangulation signals at said mobile station, wherein said plurality of forward link triangulation signals are received with increased transmitted power occurs during a duty cycle;

timestamping said forward link triangulation signals within said mobile station;

calculating a first hyperbola and a second hyperbola from said timestamped forward link triangulation signals; and

calculating the intersection of said first hyperbola and said second hyperbola.

20. The machine-readable medium of claim 19, wherein the method further comprises adjusting said duty cycle such that average transmitted power is limited to a predetermined level.

21. The machine-readable medium of claim 19, wherein said timestamping includes calculating differential time of arrival values.

22. The machine-readable medium of claim 19, wherein said calculating said first hyperbola and said second hyperbola utilizes said differential time of arrival values.

23. The machine-readable medium of claim 19, wherein said increased transmitted power is provided from a plurality of base transceiver stations.