METHOD AND APPARATUS TO CONFIRM MOBILE EQUIPMENT HAS REMAINED RELATIVELY STATIONARY USING ONE OR MORE PILOT SIGNAL

• US 20100113061A1
• Filed: 10/31/2008
• Published: 05/06/2010
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Holcman, Alejandro R.
• Granted Patent: US 8,639,262 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/02524 Creating or updating the radio-map

Abstract

A tracking unit operably coupled to mobile equipment is provided. The tracking unit is capable of using a pilot channel for CDMA networks, a broadcast channel for GSM networks or the like, to determine that the tracking unit has remained relatively stationary. The tracking unit determines it has remained relatively stationary by determining that it is receiving the same radio frequency signals at approximately the same strength as it previously received.

Claims

1. A method of using received radio frequency signals to determine whether mobile equipment has remained relatively stationary;

the method comprising;

storing a first strength of a radio frequency signal previously received by a tracking unit of the mobile equipment;

subsequently receiving at the mobile equipment the radio frequency signal;

calculating a second strength of the subsequently received radio frequency signal;

comparing the second strength to the first strength,

determining that the mobile equipment is substantially at a previously determined location if the second strength is with a predetermined tolerance of the first strength, whereby

it can be determined that the mobile equipment has been relatively stationary without performing a location determination.

2. The method of claim 1 wherein storing the first strength of a radio frequency signal comprises storing a plurality of first strengths of a plurality of radio frequency signals.

3. The method of claim 1 wherein the first strength comprises a previous minimum signal strength and a previous maximum signal strength, and wherein the comparing the second strength to the first strength comprises determining that the second strength is no less than a first predetermined amount below the previous minimum signal and no more than a second predetermined amount above the previous maximum signal.

4. The method of claim 3 wherein the first predetermined amount is equal to the second predetermined amount.

5. The method of claim 1 wherein the radio frequency signal comprises the pilot channel for a CDMA network.

6. The method of claim 5 wherein the first strength comprises a previous pilot strength and the second strength comprises a current pilot strength.

7. The method of claim 5 comprising:

storing a first pilot PN associated with the previous pilot strength;

determining a second pilot PN associated with a current pilot channel;

comparing the first pilot PN to the second pilot PN whereby

it is determined the mobile equipment has remained relatively stationary only if the first pilot PN equals the second pilot PN.

8. The method of claim 1 comprising:

obtaining an actual position of the mobile equipment; and

adjusting the predetermined tolerance based on the actual position determination of the mobile equipment.

9. The method of claim 7 wherein the radio frequency signal comprises a plurality of pilot channels, and wherein the first pilot PN comprises a plurality of first pilot PNs and the second pilot PN comprises a plurality of second pilot PNs.

10. The method of claim 1 wherein the radio frequency signal comprises at least one of a broadcast channel of a GSM network or a common pilot channel of an UMTS network.

11. The method of claim 1 wherein the step of storing a first strength of a radio frequency signal previously received by a tracking unit of the mobile equipment comprises averaging all previously recorded strengths of the radio frequency signal.

12. The method of claim 11, wherein the average is a weighted average.

13. A method of using received radio frequency signals to determine whether mobile equipment has remained relatively stationary;

the method comprising;

receiving at the mobile equipment at least one repetitive radio frequency signal;

establishing a database comprising information of previously received repetitive radio frequency signals received at the mobile equipment, the information comprising an identifier for each previously received repetitive radio frequency signal and a strength for each previously received repetitive radio frequency signal;

comparing information of a currently received repetitive radio frequency signal to information in the database of previously received repetitive radio frequency signals to determine whether the mobile equipment is approximately in the same location; and

updating the information in the database with the information from the currently received repetitive radio frequency signal.

14. The method of claim 13 wherein the identifier is a pilot PN and the strength is a pilot strength.

15. The method of claim 14, wherein the information in the database comprises the time of day that the pilot PN and the pilot strength are determined such that the comparison compares information from approximately the same time of day.

16. The method of claim 14, wherein the step of establishing the database comprises extracting from the received repetitive radio frequency signal an identifier of each radio frequency signal and calculating a strength of the received repetitive radio frequency signal and storing the identifier and the associated strength as the information in the database.

17. The method of claim 16 wherein the updating step comprises averaging the information from the previously received repetitive radio frequency signals with the currently received repetitive radio frequency signal.

18. The method of claim 13 wherein the updating the information comprising comparing the currently received repetitive radio frequency signal with a minimum previously received repetitive radio frequency signal and replacing the minimum previously received repetitive radio frequency signal with the currently received repetitive radio frequency signal.

19. The method of claim 13 wherein the updating the information comprising comparing the currently received repetitive radio frequency signal with a maximum previously received repetitive radio frequency signal and replacing the maximum previously received repetitive radio frequency signal with the currently received repetitive radio frequency signal.

20. The method of claim 13 wherein the information includes at least one position determination for the previously received repetitive radio frequency signals.

24. The tracking unit of claim 20 wherein the wireless receiver receives at least one of broadcast channels from base stations operating under GSM or common pilot channels from base stations operating under UMTS Network.

25. The tracking unit of claim 20 comprising a location determination sensor operably coupled to the controller wherein the location of the tracking unit is determinable.

26. The tracking unit of claim 24 wherein the location determination sensor is a GPS receiver.

27. The tracking unit of claim 20 wherein the controller is operably coupled to the memory to erase the information if the controller determines the tracking unit moved from a previous location.

28. The tracking unit of claim 20 wherein the controller is operable to determine that the mobile equipment has remained relatively stationary after the memory stores previously received radio frequency transmissions.

21. A tracking unit operably coupled to mobile equipment to determine whether the mobile equipment has been relatively stationary comprising:

a wireless receiver operable to receive current radio frequency transmissions;

a controller operably coupled to the wireless receiver to extract information from the current radio frequency transmissions, the information comprising an identifier for each of the radio frequency transmissions and a strength for each of the radio frequency transmissions; and

a memory to store the information of previously received radio frequency transmissions, wherein

the controller is operable to compare the information of the current radio frequency transmissions to the previously received radio frequency transmissions to determine that the mobile equipment has remained relatively stationary.

22. The tracking unit of claim 21 wherein the wireless receiver receives pilot channel transmissions from base stations operating under CDMA.

23. The tracking unit of claim 21 wherein the controller extracts the pilot PN and the pilot strength from the pilot channel transmissions and stores the pilot PN and the pilot strength as the information.

29. The tracking unit of claim 20 comprising a GPS receiver adapted to determine the position of the mobile equipment whereby the controller is operable to store the position of the mobile equipment in the memory and adapted to use the position of the mobile equipment to tune the ability to determine whether the mobile equipment has remained relatively stationary.

29-1. A computer program product containing computer executable code stored on a computer readable storage medium that cause a computer to:

receive current radio frequency transmissions;

extract information from the current radio frequency transmissions, the information comprising an identifier for each of the radio frequency transmissions and a strength for each of the radio frequency transmissions; and

store the information of previously received radio frequency transmissions; and

compare the information of the current radio frequency transmissions to the previously received radio frequency transmissions to determine that the mobile equipment has remained relatively stationary.

30. A tracking unit to receive radio frequency signals to determine whether mobile equipment has remained relatively stationary;

the tracking unit comprising;

means for storing a first strength of a radio frequency signal previously received by a tracking unit of the mobile equipment;

means for receiving at the mobile equipment the radio frequency signal;

means for calculating a second strength of the received radio frequency signal received subsequent to storing the first strength;

means for comparing the second strength to the first strength, means for determining that the mobile equipment is substantially at a previously determined location if the second strength is with a predetermined range of the first strength, whereby

it can be determined that the mobile equipment has been relatively stationary without performing a location determination.