Method and system for femto cell self-timing and self-locating

• US 8,600,297 B2
• Filed: 07/28/2009
• Issued: 12/03/2013
• Est. Priority Date: 07/28/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ketchum, John W., Nagaraj, Srinath, Bhatia, Ashok, Katzfey, Eric J., Daita, Lalitaprasad V., Baruah, Sekharjyoti
• Primary Examiner(s): TAYLOR, BARRY W
• Application Number:
  US12/510,916
• Publication Number:
  US 20110028166A1
• Time in Patent Office: 1,589 Days
• Field of Search: 455/502, 455/12.1, 455/13.2, 370/395.62, 370/503, 370/518
• US Class Current: 455/13.2
• CPC Class Codes: H04J 3/0688 Change of the master or reference, e.g. take-over or failure of the master
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase
• CPC Class Codes: H04W 64/003 locating network equipment
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

Devices and methods are provided for providing self-timing and self-locating in an access point (AP) base station. In one embodiment, the method involves receiving Satellite Positioning System (SPS) signals from a first data source (e.g., plurality of satellites), wherein the SPS signals may include SPS time data, SPS frequency data, and SPS position data. The method may further involve obtaining from a second data source (e.g., cell site, terrestrial navigation station, server, user input interface, etc.) at least one of second time data, second frequency data and second position data, and determining relative reliability of the first and second data sources.

Claims

1. A wireless communication device, comprising:

a Satellite Positioning System (SPS) receiver for acquiring SPS signals from a first data source, the SPS signals comprising SPS time data, SPS frequency data, and SPS position data;

a backhaul interface for a communication backhaul in operative communication with a macro network;

a transceiver module for communicating with at least one of (a) an access terminal (AT), (b) the macro network via the communication backhaul, (c) a base station in operative communication with the macro network, and (d) an alternative data source;

an internal clock;

at least one processor operatively coupled with the SPS receiver, the backhaul interface, the transceiver module, and the internal clock; and

a memory module operatively coupled with the at least one processor and comprising executable code for the at least one processor to;

determine an SPS time error based on the SPS time data;

determine an SPS frequency error based on the SPS frequency data;

determine an SPS position error based on the SPS position data;

obtain a time error threshold, a frequency error threshold, and a position error threshold, wherein at least one of the time error threshold, the frequency error threshold, and the position error threshold comprises both a low water mark value and a high water mark value;

in response to the SPS time error not exceeding the time error threshold, synchronize the internal clock based at least in part on the SPS time data;

in response to the SPS frequency error not exceeding the frequency error threshold, obtain a frequency reference based at least in part on the SPS frequency data;

in response to the SPS position error not exceeding the position error threshold, estimate a location of the device based at least in part on the SPS position data; and

communicate with a second data source via the transceiver module to obtain at least one of second time data, second frequency data and second position data,

wherein the at least one processor is further configured to;

in response to one of the time error, frequency error and position error exceeding the low water mark value, a first defined action, and

in response to one of the time error, frequency error and position error exceeding the high water mark, perform a second defined action.

2. The device of claim 1, wherein the at least one processor determines a relative reliability of the first data source and the second data source by comparing at least one of (i) the SPS time data and the second time data, (ii) the SPS frequency data and the second frequency data, and (iii) the SPS position data and the second position data.

3. The device of claim 2, wherein the at least one processor gives a greater weight to information from one of the first data source and the second data source based on the relative reliability.

4. The device of claim 2, wherein the at least one processor utilizes information from a selected one of the first data source and the second data source based on the relative reliability.

5. The device of claim 1, wherein the at least one processor:

determines a second time error based on the second time data;

determines a second frequency error based on the second frequency data;

determines a second position error based on the second position data;

in response to the second time error not exceeding the time error threshold, synchronizes the internal clock based at least in part on the second time data;

in response to the second frequency error not exceeding the frequency error threshold, obtains the frequency reference based at least in part on the second frequency data;

in response to the second position error not exceeding the position error threshold, estimates the location of the device based at least in part on the second position data; and

communicates with a third data source via the transceiver module to obtain at least one of third time data, third frequency data and third position data from the third data source.

6. The device of claim 5, wherein the at least one processor determines a relative reliability of the second data source and the third data source by comparing at least one of (i) the second time data and the third time data, (ii) the second frequency data and the third frequency data, and (iii) the second position data and the third position data.

7. The device of claim 6, wherein the at least one processor gives a greater weight to information from one of the second data source and the third data source based on the relative reliability.

8. The device of claim 6, wherein the at least one processor utilizes information from a selected one of the second data source and the third data source based on the relative reliability.

9. The device of claim 6, wherein the second data source comprises a cell site of the macro network, and the third data source comprises another cell site of the macro network.

10. The device of claim 1, wherein the first data source comprises a plurality of satellites of a Global Positioning Satellite (GPS) system.

11. The device of claim 10, wherein:

the SPS time data comprises a GPS time stamp included in a GPS signal of the GPS system; and

the SPS frequency data comprises a GPS frequency reference included in the GPS signal.

12. The device of claim 1, wherein the first data source comprises an Assisted GPS (A-GPS) system.

13. The device of claim 12, wherein:

the transceiver module downloads satellite almanac and ephemeris information via the communication backhaul; and

the at least one processor uses the downloaded information to assist the SPS receiver estimate at least one of the location of the device and GPS time.

14. The device of claim 1, wherein the second data source comprises a cell site of the macro network.

15. The device of claim 14, wherein the transceiver module receives at least one of a pilot signal and a sync channel signal from the cell site.

16. The device of claim 15, wherein the at least one processor;

determines a cell location of the cell site based on the at least one of the pilot signal and the sync channel signal; and

uses the cell, location as a starting estimate for the location of the device.

17. The device of claim 15, wherein the at least one processor calculates pseudo-range information from at least one of the pilot signal and the sync channel signal.

18. The device of claim 17, wherein the at least one processor uses the pseudo-range information to estimate at least one of the location of the device and GPS time.

19. The device of claim 1, wherein the second data source comprises a terrestrial navigation system.

20. The device of claim 19, wherein the terrestrial navigation system comprises a Long Range Aid to Navigation-C (LORAN-C) system.

21. The device of claim 20, wherein the at least one processor calculates pseudo-range information based at least in part on a LORAN-C signal from a LORAN-C station.

22. The device of claim 21, wherein the at least one processor:

uses the pseudo-range information to estimate at least one of the location of the device and GPS time; and

uses the LORAN-C signal to discipline a local oscillator and to track GPS time based at least in part on the location of the device.

23. The device of claim 1, wherein the second data source comprises a server in operative communication with the device via the communication backhaul.

24. The device of claim 23, wherein the server comprises at least one of Network Time Protocol (NTP) and Precision Time Protocol (PTP).

25. The device of claim 24, wherein the transceiver module:

sends pseudo-range information and local clock information to the server via the communication backhaul; and

receives from the server at least one of (a) an estimated device location and (b) an estimated GPS time, wherein the at least one of the estimated device location and the estimated GPS time are based at least in part on the pseudo-range information and the local clock information.

26. The device of claim 25, wherein the at least one processor implements advanced forward link trilateration (AFLT).

27. The device of claim 1, wherein the second data source comprises a user input interface configured to receive a user input data regarding at least one of GPS time, the frequency reference, and the location of the device.

28. The device of claim 1, wherein the second data source comprises an external hardware interface configured to receive external pulse data regarding at least one of GPS time, the frequency reference, and the location of the device.

29. The device of claim 28, wherein the external pulse data comprises a pulse-per-2-seconds (PP2S) signal injected into a general purpose input/output (GPIO) port in operative communication with the transceiver module.

30. The device of claim 1, wherein the at least one processor estimates the location of the device based at least in port on an Internet Protocol (IP) address associated with the communication backhaul.

31. The device of claim 1, wherein the at least one processor, in response to detecting a change in the location of the device, notifies a host cellular network of the change.

32. The device of claim 1, wherein the at least one processor communicates with the second data source in response to the SPS receiver failing to acquire reliable SPS signals.

33. The device of claim 32, wherein a failure by the SPS receiver to acquire reliable SPS signals comprises at least one of (i) the SPS time error, (ii) the SPS frequency error, and (iii) the SPS position error exceeding the low or high water mark values.

34. The device of claim 32, wherein the transceiver module informs a server of the macro network, via the communication backhaul, of a failure by the SPS receiver to acquire reliable SPS signals.

35. The device of claim 1, wherein the first defined action at least comprises using another received data in conjunction with the received data for at least one calculation.

36. The device of claim 1, wherein the second defined action at least comprises notifying a server of the macro network regarding unreliability of the received data.

37. The device of claim 1, wherein at least a portion of the received data comprises at least one of the SPS time data, the SPS frequency data, and the SPS position data.

38. The device of claim 1, wherein the base station comprises one of a macro base station and an AP base station.

39. A method for facilitating self-timing and self-locating by an AP base station, comprising:

receiving SPS signals from a first data source, the SPS signals comprising SPS time data, SPS frequency data, and SPS position data;

interfacing with a communication backhaul in operative communication with a macro network;

communicating with at least one of (a) an access terminal (AT), (b) the macro network via the communication backhaul, (c) a base station in operative communication with the macro network, and (d) an alternative data source;

determining an SPS time error based on the SPS time data;

determining an SPS frequency error based on the SPS frequency data;

determining an SPS position error based on the SPS position data;

obtaining a time error threshold, a frequency error threshold, and a position error threshold, wherein at least one of the time error threshold, the frequency error threshold and the position error threshold comprises both a low water mark value and a high water mark value;

synchronizing an internal clock based at least in part on the SPS time data, in response to the SPS time error not exceeding the time error threshold;

obtaining a frequency reference based at least in part on the SPS frequency data, in response to the SPS frequency error not exceeding the frequency error threshold;

estimating a location of the AP base station based at least in part on the SPS position data, in response to the SPS position error not exceeding the position error threshold;

obtaining from a second data source at least one of second time data, second frequency data and second position data;

in response to one of the time error frequency error and position error exceeding the low water mark value, performing a first defined action; and

in response to one of the time error, frequency error and position error exceeding the high water mark, performing is second defined action.

40. The method of claim 39, further comprising determining a relative reliability of the first data source and the second data source by comparing at least one of (i) the SPS time data and the second time data, (ii) the SPS frequency data and the second frequency data, and (iii) the SPS position data and the second position data.

41. The method of claim 40, further comprising giving a greater weight to information from one of the first data source and the second data source based on the relative reliability.

42. The method of claim 40, further comprising utilizing information from a selected one of the first data source and the second data source based on the relative reliability.

43. The method of claim 39, further comprising:

determining a second time error based on the second time data;

determining a second frequency error based on the second frequency data;

determining a second position error based on the second position data;

in response to the second time error not exceeding the time error threshold, synchronizing the internal clock based at least in part on the second time data;

in response to the second frequency error not exceeding the frequency error threshold, obtaining the frequency reference based at least in part on the second frequency data;

in response to the second position error not exceeding the position error threshold, estimating the location of the AP base station based at least in part on the second position data; and

communicating with a third data source via the transceiver module to obtain at least one of third time data, third frequency data and third position data from the third data source.

44. The method or claim 43, further comprising determining a relative reliability of the second data source and the third data source by comparing at least one of (i) the second time data and the third time data, (ii) the second frequency data and the third frequency data, and (iii) the second position data and the third position data.

45. The method of claim 44, further comprising giving a greater weight to information from one of the second data source and the third data source based on the relative reliability.

46. The method of claim 44, further comprising utilizing information from a selected one of the second data source and the third data source based on the relative reliability.

47. The method of claim 39, wherein obtaining from the second data source comprises obtaining from a cell site of the macro network.

48. The method of claim 47, wherein obtaining from the cell site comprises receiving at least one of a pilot signal and a sync channel signal from the cell site.

49. The method of claim 48, further comprising:

determining a cell location of the cell site based on the at least one of the pilot signal and the sync channel signal; and

using the cell location as a starting estimate for the location of the AP base station.

50. The method of claim 48, further comprising calculating pseudo-range information from at least one of the pilot signal and the sync channel signal.

51. The method of claim 39, wherein obtaining from the second data source comprises obtaining from a Long Range Aid to Navigation-C (LORAN-C) system.

52. The method of claim 51, further comprising:

calculating pseudo-range information based at least in part on LORAN-C signal from a LORAN-C station;

using the pseudo-range information to estimate at least one of the location of the AP base station and GPS time; and

using the LORAN-C signal to discipline a local oscillator and to track GPS time based at least in part on the location of the AP base station.

53. The method of claim 39, wherein obtaining from the second data source comprises obtaining from a server via the communication backhaul.

54. The method of claim 53, further comprising:

sending pseudo-range information and local clock information to the server via the communication backhaul; and

receiving from the server at least one of (a) an estimated device location and (b) an estimated GPS time, wherein the at least one of the estimated device location and the estimated GPS time are based at least in part on the pseudo-range information and the local clock information.

55. The method of claim 54, further comprising implementing advanced forward link trilateration (AFLT).

56. The method of claim 39, wherein obtaining from the second data source comprises obtaining from a user input interface configured to receive a user input data regarding at least one of GPS time, the frequency reference, and the location of the AP base station.

57. The method of claim 39, wherein performing the first action comprises using another received data in conjunction with the received data for at least one calculation.

58. The method of claim 39, wherein performing the second action comprises notifying a server of the macro network regarding unreliability of the received data.

59. A wireless communication apparatus, comprising:

means for receiving SPS signals from a first data source, the SPS signals comprising SPS time data, SPS frequency data, and SPS position data;

means for interfacing with a communication backhaul in operative communication with a macro network;

means for communicating with at least one of (a) an access terminal (AT), (b) the macro network via the communication backhaul, (c) a base station in operative communication with the macro network, and (d) an alternative data source;

means for determining an SPS time error based on the SPS time data;

means for determining an SPS frequency error based on the SPS frequency data;

means for determining an SPS position error based on the SPS position data;

means for obtaining a time error threshold, a frequency error threshold, and a position error threshold wherein at least one of the time error threshold, the frequency error threshold, and the position error threshold comprises both a low water mark value and a high water mark value;

means for synchronizing an internal clock based at least in part on the SPS time data, in response to the SPS time error not exceeding the time error threshold;

means for obtaining a frequency reference based at least in part on the SPS frequency data in response to the SPS frequency error not exceeding the frequency error threshold;

means for estimating a location of the apparatus based at least in part on the SPS position data in response to the SPS position error not exceeding the position error threshold;

means for obtaining from a second data source at least one of second time data, second frequency data and second position data;

in response to one of the time error, frequency error and position error exceeding the low water mark value, means for first defined action; and

in response to one of the time error, frequency error and position error exceeding the high water mark, means for performing a second defined action.

60. The apparatus of claim 59, further comprising means for determining a relative reliability of the first data source and the second data source by comparing at least one of (i) the SPS time data and the second time data, (ii) the SPS frequency data and the second frequency data, and (iii) the SPS position data and the second position data.

61. The apparatus of claim 60, wherein at least one of the means for synchronizing the internal clock, the means for obtaining the frequency reference, and the means for estimating the location of the apparatus gives a greater weight to information from one of the first data source and the second data source based on the relative reliability.

62. The apparatus of claim 60, wherein at least one of the means for synchronizing the internal clock, the means for obtaining the frequency reference, and the means for estimating the location of the apparatus utilizes information from a selected one of the first data source and the second data source based on the relative reliability.

63. The apparatus of claim 59, further comprising:

means for determining a second time error based on the second time data;

means for determining a second frequency error based on the second frequency data;

means for determining a second position error based on the second position data;

means for synchronizing an internal clock based at least in part on the second time data in response to the second time error not exceeding the time error threshold;

means for obtaining the frequency reference based at least in part on the second frequency data in response to the second frequency error not exceeding the frequency error threshold;

means for estimating the location of the apparatus based at least in part on the second position data in response to the second position error not exceeding the position error threshold; and

means for communicating with a third data source via the transceiver module to obtain at least one of third time data, third frequency data and third position data from the third data source.

64. The apparatus of claim 63, further comprising means for determining a relative reliability of the second data source and the third data source by comparing at least one of (i) the second time data and the third time data, (ii) the second frequency data and the third frequency data, and (iii) the second position data and the third position data.

65. The apparatus of claim 59, wherein the second data source comprises a cell site of the macro network.

66. The apparatus of claim 65, wherein the means for obtaining from the second data source receives at least one of a pilot signal and a sync channel signal from the cell site.

67. The apparatus of claim 59, wherein the second data source comprises a Long Range Aid to Navigation-C (LORAN-C) system.

68. The apparatus of claim 59, wherein the second data source comprises a server in operative communication with the apparatus via the means for communicating.

69. The apparatus of claim 68, wherein the means for communicating:

sends pseudo-range information and local clock information to the server via the communication backhaul; and

receives from the server at least one of (a) an estimated device location and (b) an estimated GPS time, wherein the at least one of the estimated device location and the estimated GPS time are based at least in part on the pseudo-range information and the local clock information.

70. The apparatus of claim 69, further comprising means for implementing advanced forward link trilateration (AFLT).

71. The apparatus of claim 59, wherein the second data source comprises a user input interface configured to receive a user input data regarding at least one of GPS time, the frequency reference, and the location of the apparatus.

72. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing a computer to receive SPS signals from a first data source, the SPS signals comprising SPS time data, SPS frequency data, and SPS position data;

code for causing the computer to interface with a communication backhaul in operative communication with a macro network;

code for causing the computer to communicate with at least one of (a) an access terminal (AT), (b) the macro network via the communication backhaul, (c) a base station in operative communication with the macro network, and (d) an alternative data source;

code for causing the computer to determine an SPS time error based on the SPS time data;

code for causing the computer to determine an SPS frequency error based on the SPS frequency data;

code for causing the computer to determine an SPS position error based on the SPS position data;

code for causing the computer to obtain a time error threshold, a frequency error threshold, and a position error threshold, wherein at least one of the time error threshold, the frequency error threshhold, and the position error threshold comprises both a low water mark value and a high water mark value;

code for causing the computer to synchronize an internal clock based at least in part on the SPS time data, in response to the SPS time error not exceeding the time error threshold;

code for causing the computer to obtain a frequency reference based at least in part on the SPS frequency data, in response to the SPS frequency error not exceeding the frequency error threshold;

code for causing the computer to estimate a location of the computer based at least in part on the SPS position data, in response to the SPS position error not exceeding the position error threshold;

code for causing the computer to obtain from a second data source at least one of second time data, second frequency data and second position data;

in response to one of the time error, frequent error and position error exceeding the low water mark value, code for causing the computer to perform a first defined action; and

in response to one of the time error, frequency error and position error exceeding the high water mark, code for causing the computer to perform a second defined action.