Methods and apparatuses for use in mobile device positioning systems

• US 8,249,619 B2
• Filed: 10/07/2008
• Issued: 08/21/2012
• Est. Priority Date: 10/07/2008
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kong, Seung Hyun
• Primary Examiner(s): Gary, Erika
• Application Number:
  US12/246,979
• Publication Number:
  US 20100087205A1
• Time in Patent Office: 1,414 Days
• Field of Search: None
• US Class Current: 455/456.1
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Methods and apparatuses are provided which may be adapted for use in and/or with mobile device positioning systems and/or the like. In an example, a method may include accessing a plurality of measurements associated with a plurality of location signals as received by the mobile device from at least a first portion of a plurality of transmitters. The method may include dynamically establishing at least one location signal transmission parameter based, at least in part, on the plurality of measurements. The location signal transmission parameter(s) may be adapted for use by at least a second portion of the plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals adapted to be received by the mobile device.

Claims

1. A method for use in a mobile device positioning system, the method comprising:

accessing a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

dynamically establishing at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device.

2. The method as recited in claim 1, wherein said location signal transmission parameter is configured to operatively establish said second portion of said plurality of transmitters.

3. The method as recited in claim 1, wherein said plurality of location signals are received by said mobile device during a search period, and said location signal transmission parameter is configured to operatively adapt at least said second portion of said plurality of transmitters to transmit said additional plurality of location signals during a subsequent search period.

4. The method as recited in claim 1, wherein said location signal transmission parameter is configured to operatively increase or decrease a number of transmitters that transmit said additional plurality of location signals during a subsequent search period.

5. The method as recited in claim 1, wherein said first portion of said plurality of transmitters comprises at least a first transmitter located at a first distance from said mobile device and wherein said second portion of said plurality of transmitters comprises at least a second transmitter located at a second distance from said mobile device, and wherein said first and second distances are different.

6. The method as recited in claim 1, wherein at least one of said plurality of location signals as received by said mobile device from at least one transmitter in said first portion of said plurality of transmitters is selectively transmitted there from based, at least in part, on an initial location signal transmission parameter.

7. The method as recited in claim 1, wherein said at least one location signal transmission parameter comprises a rate parameter, said rate parameter configured to facilitate a location signal transmission operation associated with at least said second portion of said plurality of transmitters to operatively initiate transmission of said additional plurality of location signals.

8. The method as recited in claim 7, wherein a change of said rate parameter associated with said location signal transmission operation correspondingly operatively changes a number of transmitters in said second portion.

9. The method as recited in claim 7, wherein said rate parameter identifies a transmission timing ratio.

10. The method as recited in claim 1, further comprising, during a subsequent search period, selectively transmitting two or more of said additional plurality of location signals from at least one transmitter in said second portion based, at least in part, on said at least one location signal transmission parameter.

11. The method as recited in claim 1, further comprising determining said plurality of measurements with said mobile device.

12. The method as recited in claim 1, wherein said plurality of measurements comprise at least one of a signal strength measurement, a code phase measurement, a relative signal strength measurement, and/or a relative code phase measurement.

13. The method as recited in claim 1, further comprising transmitting said plurality of measurements from said mobile device to at least one network resource.

15. The method as recited in claim 1, A method for use in a mobile device positioning system, the method comprising:

accessing a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

dynamically establishing at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device, wherein dynamically establishing said at least one location signal transmission parameter comprises;

estimating a location of said mobile device based, at least in part, on said plurality of measurements;

determining a dilution of precision (DOP) and/or a number of geographically distinctive transmitters (N_GDT) associated with said estimated location and said first portion of said plurality of transmitters; and

determining a rate parameter associated with a location signal transmission operation based, at least in part, on said DOP and/or said N_GDT.

16. The method as recited in claim 15, wherein determining said rate parameter comprises determining said rate parameter based, at least in part, on said DOP and a threshold DOP, and/or said N_GDT and a threshold N_GDT.

17. The method as recited in claim 16, wherein threshold DOP is associated with an acceptable or minimum number of transmitters to be included within said second portion.

14. A method for use in a mobile device positioning system, the method comprising:

accessing a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

dynamically establishing at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device, wherein at least one of said additional plurality of location signals comprises a Highly Detectable Pilot (HDP) signal and/or an Idle Period Down Link (IPDL) pilot signal.

18. An apparatus for use in a mobile device positioning system, the apparatus comprising:

memory configured to store a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

at least one processing unit coupled to said memory and configured to dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device.

19. The apparatus as recited in claim 18, further comprising a network interface coupled to at least one of said at least one processing unit and/or said memory and configured to receive said plurality of measurements over a network.

20. The apparatus as recited in claim 18, further comprising a network interface coupled to at least one of said at least one processing unit and/or said memory and configured to at least transmit said at least one location signal transmission parameter over a network to at least one transmitter in said second portion.

21. The apparatus as recited in claim 18, wherein said at least one location signal transmission parameter is configured to operatively establish said second portion of said plurality of transmitters.

22. The apparatus as recited in claim 18, wherein said plurality of location signals are received by said mobile device during a search period, and wherein said location signal transmission parameter is configured to operatively adapt at least said second portion of said plurality of transmitters to transmit said additional plurality of location signals during a subsequent search period.

23. The apparatus as recited in claim 18, wherein said location signal transmission parameter is configured to increase or decrease a number of transmitters that transmit said additional plurality of location signals during a subsequent search period.

24. The apparatus as recited in claim 18, wherein said first portion of said plurality of transmitters comprises at least a first transmitter located at a first distance from said mobile device and wherein said second portion of said plurality of transmitters comprises at least a second transmitter located at a second distance from said mobile device, and wherein said first and second distances are different.

25. The apparatus as recited in claim 18, wherein said at least one location signal transmission parameter comprises a rate parameter, said rate parameter configured to facilitate a location signal transmission operation associated with at least said second portion of said plurality of transmitters to operatively initiate transmission of said additional plurality of location signals.

26. An apparatus for use in a mobile device positioning system, the apparatus comprising:

memory configured to store a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

at least one processing unit coupled to said memory and configured to dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device,

wherein said at least one location signal transmission parameter comprises a rate parameter, said rate parameter configured to facilitate a location signal transmission operation associated with at least said second portion of said plurality of transmitters to operatively initiate transmission of said additional plurality of location signals, and

wherein said rate parameter is configured to initiate at least one transmitter in said second portion of said plurality of transmitters to transmit at least one of said additional plurality of location signals, said at least one of said additional plurality of location signals comprising a Highly Detectable Pilot (HDP) signal and/or an Idle Period Down Link (IPDL) pilot signal.

27. An apparatus for use in a mobile device positioning system, the apparatus comprising:

memory configured to store a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

at least one processing unit coupled to said memory and configured to dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device, wherein said at least one processing unit is further configured to;

estimate a location of said mobile device based, at least in part, on said plurality of measurements;

determine a dilution of precision (DOP) and/or a number of geographically distinctive transmitters (N_GDT) associated with said estimated location and said first portion of said plurality of transmitters; and

establish a rate parameter associated with a location signal transmission operation based, at least in part, on said DOP and/or said N_GDT.

28. The apparatus as recited in claim 27, wherein establishing said rate parameter comprises establishing said rate parameter based, at least in part, on said DOP and a threshold DOP, and/or said N_GDT and a threshold N_GDT, said threshold DOP and/or said threshold N_GDT being associated with an acceptable or minimum number of transmitters to be included within said second portion.

29. An apparatus for a mobile device for use in a mobile device positioning system, the apparatus comprising:

memory;

a wireless communication interface coupled to said memory and configured to receive a plurality of location signals from at least a first portion of a plurality of transmitters and provide a plurality of measurements to said memory, said plurality of measurements being based, at least in part, on said plurality of location signals; and

at least one processing unit coupled to said memory and configured to dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device, and

wherein said wireless communication interface is further configured to transmit said at least one location signal transmission parameter over a wireless communication link.

30. The apparatus as recited in claim 29, wherein said at least one location signal transmission parameter is configured to operatively establish said second portion of said plurality of transmitters.

31. The apparatus as recited in claim 29, wherein said plurality of location signals are received by said wireless communication interface during a search period, and said location signal transmission parameter is configured to operatively adapt at least said second portion of said plurality of transmitters to transmit said additional plurality of location signals during a subsequent search period.

32. The apparatus as recited in claim 29, wherein said location signal transmission parameter is configured to increase or decrease a number of transmitters that transmit said additional plurality of location signals during a subsequent search period.

33. The apparatus as recited in claim 29, wherein said first portion of said plurality of transmitters comprises at least a first transmitter located at a first distance from said mobile device and wherein said second portion of said plurality of transmitters comprises at least a second transmitter located at a second distance from said mobile device, and wherein said first and second distances are different.

34. The apparatus as recited in claim 29, wherein said at least one location signal transmission parameter comprises a rate parameter, said rate parameter configured to facilitate a location signal transmission operation associated with at least said second portion of said plurality of transmitters to operatively initiate transmission of said additional plurality of location signals.

35. An apparatus for a mobile device for use in a mobile device positioning system, the apparatus comprising:

memory;

a wireless communication interface coupled to said memory and configured to receive a plurality of location signals from at least a first portion of a plurality of transmitters and provide a plurality of measurements to said memory, said plurality of measurements being based, at least in part, on said plurality of location signals; and

at least one processing unit coupled to said memory and configured to dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device,

wherein at least one of said additional plurality of location signals comprises a Highly Detectable Pilot (HDP) signal and/or an Idle Period Down Link (IPDL) pilot signal, and

wherein said wireless communication interface is further configured to transmit said at least one location signal transmission parameter over a wireless communication link.

36. An apparatus for a mobile device for use in a mobile device positioning system, the apparatus comprising:

memory;

a wireless communication interface coupled to said memory and configured to receive a plurality of location signals from at least a first portion of a plurality of transmitters and provide a plurality of measurements to said memory, said plurality of measurements being based, at least in part, on said plurality of location signals; and

at least one processing unit coupled to said memory and configured to dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device,

wherein said wireless communication interface is further configured to transmit said at least one location signal transmission parameter over a wireless communication link, and

wherein said at least one processing unit is further configured to;

estimate a location of the mobile device based, at least in part, on said plurality of measurements;

determine a dilution of precision (DOP) and/or a number of geographically distinctive transmitters (N_GDT) associated with said estimated location and said first portion of said plurality of transmitters; and

establish a rate parameter associated with a location signal transmission operation based, at least in part, on said DOP and/or said N_GDT.

37. The apparatus as recited in claim 36, wherein establishing said rate parameter comprises establishing said rate parameter based, at least in part, on said DOP and a threshold DOP, and/or said N_GDT and a threshold N_GDT, said threshold DOP and/or said threshold N_GDT being associated with an acceptable or minimum number of transmitters to be included within said second portion.

38. A system comprising:

a network;

a plurality of transmitters coupled to said network;

at least one network resource coupled to said network; and

at least one mobile device configured to receive a plurality of location signals from at least a first portion of said plurality of transmitters, determine a plurality of measurements associated with said plurality of location signals, and provide said plurality of measurements to at least one of said transmitters, and

wherein said at least one of said transmitters provides said plurality of measurements to said at least one network resource, said at least one network resource configured to dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device, and

wherein said at least one network resource is configured to provide said at least one location signal transmission parameter to at least said second portion of said plurality of transmitters over said network.

39. The system as recited in claim 38, wherein said plurality of location signals are received by said mobile device during a search period, and wherein said location signal transmission parameter is configured to operatively adapt at least said second portion of said plurality of transmitters to transmit said additional plurality of location signals during a subsequent search period.

40. The system as recited in claim 38, wherein said at least one location signal transmission parameter comprises a rate parameter, said rate parameter configured to facilitate a location signal transmission operation associated with at least said second portion of said plurality of transmitters to operatively initiate transmission of said additional plurality of location signals.

41. A system comprising:

a network;

a plurality of transmitters coupled to said network;

at least one network resource coupled to said network; and

at least one mobile device configured to receive a plurality of location signals from at least a first portion of said plurality of transmitters, determine a plurality of measurements associated with said plurality of location signals, and provide said plurality of measurements to at least one of said transmitters, and

wherein said at least one of said transmitters provides said plurality of measurements to said at least one network resource, said at least one network resource configured to dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device,

wherein at least one of said additional plurality of location signals comprises a Highly Detectable Pilot (HDP) signal and/or an Idle Period Down Link (IPDL) pilot signal, and

wherein said at least one network resource is configured to provide said at least one location signal transmission parameter to at least said second portion of said plurality of transmitters over said network.

42. A system comprising:

a network;

a plurality of transmitters coupled to said network; and

at least one mobile device configured to receive a plurality of location signals from at least a first portion of said plurality of transmitters, determine a plurality of measurements associated with said plurality of location signals, dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device.

43. The system as recited in claim 42, further comprising:

at least one network resource coupled to said network, and

wherein said mobile device is configured to provide said plurality of measurements to at least one of said transmitters, and said at least one of said transmitters provides said plurality of measurements to said at least one network resource, said at least one network resource being configured to provide said at least one location signal transmission parameter to at least said second portion of said plurality of transmitters over said network.

44. The system as recited in claim 42, wherein said plurality of location signals are received by said mobile device during a search period, and wherein said location signal transmission parameter is configured to operatively adapt at least said second portion of said plurality of transmitters to transmit said additional plurality of location signals during a subsequent search period.

45. The system as recited in claim 42, wherein said at least one location signal transmission parameter comprises a rate parameter, said rate parameter configured to facilitate a location signal transmission operation associated with at least said second portion of said plurality of transmitters to operatively initiate transmission of said additional plurality of location signals.

46. A system comprising:

a network;

a plurality of transmitters coupled to said network; and

at least one mobile device configured to receive a plurality of location signals from at least a first portion of said plurality of transmitters, determine a plurality of measurements associated with said plurality of location signals, dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device,

wherein at least one of said additional plurality of location signals comprises a Highly Detectable Pilot (HDP) signal and/or an Idle Period Down Link (IPDL) pilot signal.

47. A non-transitory computer readable medium comprising computer implementable instructions stored thereon, which if implemented adapts one or more processing units to:

access a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device.

48. The non-transitory computer readable medium as recited in claim 47, wherein said location signal transmission parameter operatively establishes said second portion of said plurality of transmitters.

49. The non-transitory computer readable medium as recited in claim 47, wherein said plurality of location signals as received by said mobile device during a search period, and said location signal transmission parameter is configured to operatively adapt at least said second portion of said plurality of transmitters to transmit said additional plurality of location signals during a subsequent search period.

50. The non-transitory computer readable medium comprising computer implementable instructions stored thereon, which if implemented adapts one or more processing units to:

access a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device,

wherein said at least one location signal transmission parameter comprises a rate parameter, said rate parameter configured to facilitate a location signal transmission operation associated with at least said second portion of said plurality of transmitters to operatively initiate transmission of said additional plurality of location signals, and wherein at least one of said additional plurality of location signals comprises a Highly Detectable Pilot (HDP) signal and/or an Idle Period Down Link (IPDL) pilot signal.

51. The non-transitory computer readable medium comprising computer implementable instructions stored thereon, which if implemented adapt said one or more processing units to:

access a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

dynamically establish at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device,

estimate a location of said mobile device based, at least in part, on said plurality of measurements;

determine a dilution of precision (DOP) and/or a number of geographically distinctive transmitters (N_GDT) associated with said estimated location and said first portion of said plurality of transmitters; and

determine a rate parameter associated with a location signal transmission operation based, at least in part, on said DOP and a threshold DOP, and/or said N_GDT and a threshold N_GDT, said threshold DOP and/or said threshold N_GDT being associated with an acceptable or minimum number of transmitters to be included within said second portion.

52. An apparatus for use in a mobile device positioning system, the apparatus comprising:

means for storing a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

means for dynamically establishing at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device.

53. The apparatus as recited in claim 52, wherein said at least one location signal transmission parameter is configured to operatively establish said second portion of said plurality of transmitters.

54. The apparatus as recited in claim 52, wherein said plurality of location signals are received by said mobile device during a search period, and wherein said location signal transmission parameter is configured to operatively adapt at least said second portion of said plurality of transmitters to transmit said additional plurality of location signals during a subsequent search period.

55. The apparatus as recited in claim 52, wherein said location signal transmission parameter is configured to increase or decrease a number of transmitters that transmit said additional plurality of location signals during a subsequent search period.

56. The apparatus as recited in claim 52, wherein said at least one location signal transmission parameter comprises a rate parameter, said rate parameter configured to facilitate a location signal transmission operation associated with at least said second portion of said plurality of transmitters to operatively initiate transmission of said additional plurality of location signals.

57. An apparatus for use in a mobile device positioning system, the apparatus comprising:

means for storing a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters; and

means for dynamically establishing at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device, and

wherein said rate parameter is configured to initiate at least one transmitter in said second portion of said plurality of transmitters to transmit at least one of said additional plurality of location signals, said at least one of said additional plurality of location signals comprising a Highly Detectable Pilot (HDP) signal and/or an Idle Period Down Link (IPDL) pilot signal.

58. The apparatus for use in a mobile positioning system, the apparatus comprising:

means for storing a plurality of measurements associated with a plurality of location signals as received by a mobile device from at least a first portion of a plurality of transmitters;

means for dynamically establishing at least one location signal transmission parameter based, at least in part, on said plurality of measurements, said at least one location signal transmission parameter configured to facilitate at least a second portion of said plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by said mobile device;

means for estimating a location of said mobile device based, at least in part, on said plurality of measurements;

means for determining a dilution of precision (DOP) and/or a number of geographically distinctive transmitters (NGDT) associated with said estimated location and said first portion of said plurality of transmitters; and

means for establishing a rate parameter associated with a location signal transmission operation based, at least in part, on said DOP and/or said NGDT.

59. The apparatus as recited in claim 58, further comprising means for establishing said rate parameter based, at least in part, on said DOP and a threshold DOP, and/or said N_GDT and a threshold N_GDT, said threshold DOP and/or said threshold N_GDT being associated with an acceptable or minimum number of transmitters to be included within said second portion.

60. A method performed by a network resource for use in a mobile device positioning system, the method comprising:

obtaining at least one location signal transmission parameter based, at least in part, on a plurality of measurements associated with a plurality of location signals, the at least one location signal transmission parameter configured to facilitate at least a second portion of a plurality of transmitters to operatively initiate subsequent transmission of an additional plurality of location signals configured to be received by a mobile device; and

providing the at least one location signal transmission parameter to at least the second portion of the plurality of transmitters over the network.

63. The method of claim 60, wherein the obtaining step comprises:

receiving the plurality of measurements from the mobile device; and

dynamically establishing the at least one location signal transmission parameter based, at least in part, on the plurality of measurements.

61. The method of 60, wherein the obtaining step includes:

receiving the at least one location signal transmission parameter from the mobile device.

62. The method of 60, wherein the obtaining step includes:

dynamically establishing the at least one location signal transmission parameter at the mobile device.