Ranging in UMTS networks

• US 20090124266A1
• Filed: 11/14/2007
• Published: 05/14/2009
• Est. Priority Date: 11/14/2007
• Status: Active Grant

• Current Assignee: Bison Patent Licensing, LLC
• Original Assignee: Andrew Corporation (CommScope Holding Company, Inc.)
• Inventors: Islam, Tariqul, Carlson, John
• Granted Patent: US 8,170,585 B2
• Time in Patent Office: Days
• US Class Current: 455/456.500
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and system for determining an approximate range from a location measurement unit to a mobile device. An uplink signal from the mobile device is received by the location measurement unit, and an uplink frame marker is determined from the uplink signal. A downlink signal is received at the location measurement unit from a base station serving the mobile device, and a downlink slot marker is determined from the downlink signal. A round trip propagation delay is determined based upon the uplink frame marker and the downlink slot marker, and an approximate range from the location measurement unit to the mobile device is determined as a function of the round trip propagation delay.

Claims

1. A method for determining an approximate range from a location measurement unit (“

LMU”

) to a mobile device, comprising;

(a) receiving at said LMU an uplink signal from said mobile device;

(b) determining an uplink frame marker from said uplink signal;

(c) receiving at said LMU a downlink signal from a base station serving said mobile device;

(d) determining a downlink slot marker from said downlink signal;

(e) determining a round trip propagation delay based on said uplink frame marker and said downlink slot marker; and

(f) determining an approximate range from said LMU to said mobile device as a function of said round trip propagation delay.

2. The method of claim 1 wherein determining the uplink frame marker includes:

(i) determining a first time stamp for said uplink signal; and

(ii) determining a number of samples between said first time stamp and said uplink frame marker.

3. The method of claim 2 wherein determining the downlink slot marker includes:

(i) determining a second time stamp for said downlink signal; and

(ii) determining a number of samples between said second time stamp and said downlink slot marker.

4. The method of claim 3 wherein determining the round trip propagation delay includes:

(i) shifting said downlink slot marker a number of samples such that the number of samples between said uplink frame marker and said downlink slot marker is less than 512; and

(ii) determining the number of samples between said uplink frame marker and said shifted downlink slot marker.

5. The method of claim 4 wherein determining an approximate range from said LMU to said mobile device includes multiplying the number of samples between said uplink frame marker and said shifted downlink slot marker by a predetermined number.

6. The method of claim 5 wherein said predetermined number is 19.53125.

7. The method of claim 5 wherein said number of samples between said uplink frame marker and said shifted downlink slot marker are determined by a sample rate of 7.68 MHz.

8. The method of claim 1 wherein said LMU and said serving base station are co-located.

9. The method of claim 1 wherein the downlink signal is from a sector other than the sector serving said mobile device.

10. The method of claim 1 wherein said mobile device is selected from the group consisting of:

cellular telephone, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.

11. The method of claim 1 wherein said approximate range is determined as a function of signals received from one or more LMUs installed throughout a communications network.

12. The method of claim 1 wherein said downlink slot marker is a modulo 512 multiple.

13. The method of claim 1 wherein said downlink slot marker is a function of the following relationship:

0≦

n_UL−

((t_DL−

t_UL)R+n_DL−

512N)<

512,

wherein t_UL is the time stamp of said uplink signal, t_DL is the time stamp of said downlink signal, N_UL is the time of arrival of said uplink frame marks, n_DL is the location of said downlink slot marker, R is a sample rate, and N is an integer.

14. The method of claim 1 wherein said LMU is installed in a communications network selected from the group consisting of:

Universal Mobile Telecommunications System (“

UMTS”

) network, Worldwide Interoperability for Microwave Access (“

WiMax”

) network, Global System for Mobile Communications (“

GSM”

) network, WiFi network, Code Division Multiple Access (“

CDMA”

) network.

15. The method of claim 1 wherein said LMU operates under a standard selected from the group consisting of:

IS-95, Evolution-Data Optimized (“

EDVO”

), CDMA2000, and 1 times Radio Transmission Technology (“

1×

RTT”

).

16. The method of claim 1 wherein determining the downlink slot marker includes:

(i) receiving at said LMU downlink signals from neighboring base stations,

(ii) correlating received downlink signals from a neighboring base station and said serving base station for a predetermined chip delay, and

(ii) non-coherently adding correlated signals.

17. The method of claim 16 wherein said predetermined chip delay is 256 chips.

18. A communications network for determining an approximate range to a mobile device, comprising:

(a) a location measurement unit (“

LMU”

) for receiving an uplink signal from a mobile device;

(b) circuitry for determining an uplink frame marker from said uplink signal;

(c) a base station serving said mobile device for transmitting a downlink signal to said LMU;

(d) circuitry for determining a downlink slot marker from said downlink signal;

(e) circuitry for determining a round trip propagation delay based on said uplink frame marker and said downlink slot marker; and

(f) circuitry for determining an approximate range from said LMU to said mobile device as a function of said round trip propagation delay.

19. The network of claim 18 wherein the circuitry for determining the uplink frame marker includes circuitry for:

(i) determining a first time stamp for said uplink signal; and

(ii) determining a number of samples between said first time stamp and said uplink frame marker.

20. The network of claim 19 wherein the circuitry for determining the downlink slot marker includes circuitry for:

(i) determining a second time stamp for said downlink signal; and

(ii) determining a number of samples between said second time stamp and said downlink slot marker.

21. The network of claim 20 wherein the circuitry for determining the round trip propagation delay includes circuitry for:

(i) shifting said downlink slot marker a number of samples such that the number of samples between said uplink frame marker and said downlink slot marker is less than 512; and

(ii) determining the number of samples between said uplink frame marker and said shifted downlink slot marker.

22. The network of claim 18 wherein said LMU and said serving base station are co-located.

23. The network of claim 18 wherein said downlink signal is provided from a sector other than the sector serving said mobile device.

24. The network of claim 18 wherein said mobile device is selected from the group consisting of:

cellular telephone, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.

25. The network of claim 18 wherein said approximate range is determined as a function of signals received from one or more LMUs installed throughout a communications network.

26. The network of claim 18 wherein said downlink slot marker is a modulo 512 multiple.

27. The network of claim 18 wherein said communications network is selected from the group consisting of:

Universal Mobile Telecommunications System (“

UMTS”

) network, Worldwide Interoperability for Microwave Access (“

WiMax”

) network, Global System for Mobile Communications (“

GSM”

) network, WiFi network, Code Division Multiple Access (“

CDMA”

) network.

28. The network of claim 18 wherein said communications network operates under a standard selected from the group consisting of:

IS-95, Evolution-Data Optimized (“

EDVO”

), CDMA2000, and 1 times Radio Transmission Technology (“

1×

RTT”

).

29. The network of claim 18 further comprising a second base station for transmitting a second downlink signal to said LMU, wherein said circuitry for determining a downlink slot marker includes:

(i) circuitry for correlating the downlink signal from said serving base station and said second downlink signal for a predetermined chip delay, and

(ii) circuitry for non-coherently adding the correlated signals.

30. The network of claim 29 wherein said predetermined chip delay is 256 chips.

31. A method for determining an approximate range from a location measurement unit (“

LMU”

) to a mobile device, comprising;

(a) receiving at said LMU an uplink signal from said mobile device;

(b) determining an uplink frame marker from said uplink signal;

(c) receiving at said LMU a first downlink signal from a base station serving said mobile device and a second downlink signal from a neighboring base station;

(d) determining a downlink slot marker from said first downlink signal by correlating said first and second received downlink signals for a predetermined chip delay and non-coherently adding said correlated signals;

(e) determining a round trip propagation delay based on said uplink frame marker and said downlink slot marker; and

(f) determining an approximate range from said LMU to said mobile device as a function of said round trip propagation delay.

32. The method of claim 31 wherein said predetermined chip delay is 256 chips.