Radiation Power Level Control System and Method for a Wireless Communication Device Based on a Tracked Radiation History

• US 20120021800A1
• Filed: 07/20/2010
• Published: 01/26/2012
• Est. Priority Date: 07/20/2010
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Wilson, Kelce Steven, Ali, Shirook M., Periyalwar, Shalini Suresh, Womack, James Earl
• Granted Patent: US 8,538,351 B2
• Time in Patent Office: Days
• US Class Current: 455/550.1
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 52/246 where the output power of a terminal is based on a path parameter calculated in said terminal
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal

Abstract

A radiation power level control scheme for a wireless user equipment (UE) device. In one embodiment, a power data history associated with the wireless UE device is maintained, the power data history comprising data tracked over a time window (e.g., a sliding time window) relative to one or more variables on a per transmission event basis. A component of the UE device is configured to determine a time-average transmission power level. Another component is configured to compare the time-average transmission power level with a first time-averaged transmission power limit threshold, the first time-averaged transmission power limit threshold having a value that depends on a transmission power data history for the UE device. A still further component is provided, operable responsive to the average transmission power level meeting or exceeding the first time-averaged transmission power limit threshold, that is configured to reduce a transmission power level of the UE device.

Claims

1. A radiation power level control method for a wireless user equipment (UE) device, said method comprising:

determining a time-average transmission power level;

comparing the time-average transmission power level with a first time-averaged transmission power limit threshold, the first time-averaged transmission power limit threshold having a value that depends on a transmission power history for said UE device; and

responsive to the time-average transmission power level meeting or exceeding the first time-averaged transmission power limit threshold, reducing a transmission power level of the UE device.

2. The method of claim 1 wherein reducing a transmission power level comprises reducing a number of transmission time slots used by the UE device.

3. The method of claim 2 wherein reducing a transmission power level comprises retaining, within each of the reduced number of transmission time slots, a time slot transmission power level that is consistent with a time slot transmission power level used by the UE device prior to the reducing.

4. The method of claim 1 wherein reducing a transmission power level comprises reducing a frame-average transmission power level, the frame-average transmission power level being averaged over a single transmission frame comprising multiple time slots, the time-average transmission power level being averaged over multiple transmission frames.

5. The method of claim 1 further comprising:

in conjunction with reducing a transmission power level, retaining a first communication process and suspending a second communication process.

6. The method of claim 5 wherein the first communication process comprises a voice call and the second communication process comprises a data file transfer.

7. The method of claim 5 further comprising:

in conjunction with suspending the second communication process, providing a notification to a user.

8. The method of claim 1 further comprising:

in conjunction with reducing a transmission power level, changing a modulation and coding scheme (MCS) from a first MCS to a second MCS, the second MCS providing a lower expected bit-error-rate (BER) than a BER for the first MCS at the reduced transmission power level.

9. The method of claim 1 further comprising:

comparing the time-average transmission power level with a second time-averaged transmission power limit threshold, the second time-averaged transmission power limit threshold having a lower value than the first time-averaged transmission power limit threshold; and

responsive to the time-average transmission power level meeting or falling below the second time-averaged transmission power limit threshold, increasing a transmission power level of the UE device.

10. The method of claim 9 wherein increasing a transmission power level comprises increasing a number of transmission time slots used by the UE device.

11. The method of claim 9 further comprising:

in conjunction with increasing a transmission power level, changing a modulation and coding scheme (MCS) from a first MCS to a second MCS, the second MCS providing a higher data rate than a data rate for the first MCS.

12. The method of claim 1 further comprising:

determining whether a current transmission event occurs within a predetermined duration window from a prior transmission event;

responsive to determining that the current transmission event does occur within the predetermined duration window, including at least a portion of a transmission power level history of the prior transmission event in the determined average transmission power level; and

responsive to determining that the current transmission event does not occur within the predetermined duration window, excluding the transmission power level history of the prior transmission event from the determined average transmission power level.

13. The method of claim 1 further comprising:

tracking at least one radiation history parameter selected from the list consisting of;

a time elapsed since a prior transmission event,

a duration of the prior transmission event,

a final power level of the prior transmission event,

a time-average power level of the prior transmission event, and

one or more antenna Specific Absorption Rate (SAR) values of the UE device.

14. The method of claim 1 further comprising:

determining whether changing transmission from a first antenna to a second antenna of the UE device will reduce a Specific Absorption Rate (SAR) exposure of a user of the UE device; and

responsive to determining that changing transmission from the first antenna to the second antenna will reduce a SAR exposure, ceasing transmission from the first antenna and transmitting with the second antenna.

15. The method of claim 1 further comprising:

determining whether the UE device is in use according to a private voice call mode; and

responsive to determining that the UE device is not in use according to a private voice call mode, suspending comparison of the time-average transmission power level with a first time-averaged transmission power limit threshold.

16. The method of claim 15 wherein determining whether the UE device is in use according to a private voice mode comprises determining whether the UE device is holstered.

17. The method of claim 15 wherein determining whether the UE device is in use according to a private voice mode comprises determining whether the UE device is in use according to a speakerphone mode.

18. The method of claim 17 wherein determining whether the UE device is in use according to a speakerphone mode comprises determining at least one condition selected from the list consisting of:

the speakerphone speaker is activated; and

an accelerometer indicates a horizontal orientation of the UE device.

19. The method of claim 15 wherein determining whether the UE device is in use according to a private voice mode comprises determining whether the UE device is in use according to a data entry mode.

20. The method of claim 19 wherein determining whether the UE device is in use according to a data entry mode comprises determining at least one condition selected from the list consisting of:

a UE keyboard is registering key presses at a rate that is consistent with typing by a user; and

an accelerometer indicates a data entry orientation of the UE device.

21. The method of claim 15 further comprising:

responsive to determining that the UE device is not in use according to a private voice call mode, comparing the time-average transmission power level with an alternative power limit threshold, different than the first time-averaged transmission power limit threshold.

22. The method of claim 1 further comprising:

sending a message to a serving network node, said message for indicating a change in the transmission power level of the UE device.

23. The method of claim 1 further comprising:

sending a message to a serving base station, said message for indicating a change in the transmission power level of the UE device.

24. The method of claim 1 further comprising:

reducing the first time-averaged transmission power limit threshold.

25. A wireless user equipment (UE) device comprising:

a component configured to determine a time-average transmission power level of said wireless UE device;

a component configured to compare the time-average transmission power level with a first time-averaged transmission power limit threshold, the first time-averaged transmission power limit threshold having a value that depends on a transmission power history for said UE device; and

a component, operable responsive to the average transmission power level meeting or exceeding the first time-averaged transmission power limit threshold, configured to reduce a transmission power level of the UE device.

26. The wireless UE device of claim 25 wherein the component configured to reduce a transmission power level comprises a component configured to reduce a number of transmission time slots used by the UE device.

27. The wireless UE device of claim 25 wherein reducing a transmission power level comprises retaining, within each of the reduced number of transmission time slots, a time slot transmission power level that is consistent with a time slot transmission power level used by the UE device prior to the reducing.

28. The wireless UE device of claim 25 wherein the component configured to reduce a transmission power level comprises a component configured to reduce a frame-average transmission power level, the frame-average transmission power level being averaged over a single transmission frame comprising multiple time slots, the time-average transmission power level being averaged over multiple transmission frames.

29. The wireless UE device of claim 25 further comprising:

a component, operable in conjunction with reducing a transmission power level, configured to retain a first communication process and suspending a second communication process.

30. The wireless UE device of claim 29 wherein the first communication process comprises a voice call and the second communication process comprises a data file transfer.

31. The wireless UE device of claim 29 further comprising:

a component, operable in conjunction with suspending the second communication process, configured to provide a notification to a user.

32. The wireless UE device of claim 25 further comprising:

a component, operable in conjunction with reducing a transmission power level, configured to change a modulation and coding scheme (MCS) from a first MCS to a second MCS, the second MCS providing a lower expected bit-error-rate (BER) than a BER for the first MCS at the reduced transmission power level.

33. The wireless UE device of claim 25 further comprising:

a component configured to compare the time-average transmission power level with a second time-averaged transmission power limit threshold, the second time-averaged transmission power limit threshold having a lower value than the first time-averaged transmission power limit threshold; and

a component, operable responsive to the time-average transmission power level meeting or falling below the second time-averaged transmission power limit threshold, configured to increase a transmission power level of the UE device.

34. The wireless UE device of claim 33 wherein increasing a transmission power level comprises increasing a number of transmission time slots used by the UE device.

35. The wireless UE device of claim 33 further comprising:

a component, operable in conjunction with increasing a transmission power level, configured to change a modulation and coding scheme (MCS) from a first MCS to a second MCS, the second MCS providing a higher data rate than a data rate for the first MCS.

36. The wireless UE device of claim 25 further comprising:

a component configured to determine whether a current transmission event occurs within a predetermined duration window from a prior transmission event;

a component, operable responsive to determining that the current transmission event does occur within the predetermined duration window, configured to include at least a portion of said transmission power level history of the prior transmission event in the determined average transmission power level; and

a component, operable responsive to determining that the current transmission event does not occur within the predetermined duration window, configured to exclude the transmission power level history of the prior transmission event from the determined average transmission power level.

37. The wireless UE device of claim 25 further comprising:

a component configured to track at least one radiation history parameter selected from the list consisting of;

a time elapsed since a prior transmission event, a duration of the prior transmission event, a final power level of the prior transmission event, a time-average power level of the prior transmission event, and one or more antenna specific absorption rate (SAR) values of the UE device.

38. The wireless UE device of claim 25 further comprising:

a component configured to determine whether changing transmission from a first antenna to a second antenna will reduce a specific absorption rate (SAR) exposure of a user of the UE device; and

a component, operable responsive to determining that changing transmission from the first antenna to the second antenna will reduce a SAR exposure, configured to cease transmission from the first antenna and transmitting with the second antenna.

39. The wireless UE device of claim 25 further comprising:

a component configured to determine whether the UE device is in use according to a private voice call mode; and

a component, operable responsive to determining that the UE device is not in use according to a private voice call mode, configured to suspend comparison of the time-average transmission power level with a first time-averaged transmission power limit threshold.

40. The wireless UE device of claim 39 further comprising:

a component, operable responsive to determining that the UE device is not in use according to a private voice call mode, configured to compare the time-average transmission power level with an alternative power limit threshold, different than the first time-averaged transmission power limit threshold.

41. The wireless UE device of claim 25 further comprising:

a component configured to send a message to a serving network node said message for indicating a change in the transmission power level of the UE device.

42. The wireless UE device of claim 25 further comprising:

a component configured to send a message to a serving base station, said message for indicating a change in the transmission power level of the UE device.

43. The wireless UE device of claim 25 further comprising:

a storage element for storing a transmission power level history associated with said wireless UE device, said transmission power level history comprising data tracked over a time window relative to one or more variables.

44. The wireless UE device of claim 25 further comprising:

a component configured to reduce the first time-averaged transmission power limit threshold.

45. A radiation power level control method for a wireless user equipment (UE) device, said method comprising:

determining that a current transmission event involving said wireless UE device occurred within a predetermined duration from a last transmission event;

responsive to said determining, using a power data history associated with said wireless UE device in determining one or more Specific Absorption Rate (SAR) values during said current transmission event, said power data history comprising data tracked over a time window relative to one or more variables;

if said current transmission event occurred outside said predetermined duration from said last transmission event, resetting said power data history and using said reset power data history in determining said one or more SAR values during said current transmission event; and

if at least one of said one or more SAR values exceeds a threshold, effectuating a control action relative to said current transmission event, said control action including at least reducing a transmission power level radiating from at least one radio frequency (RF) antenna of said wireless UE device.

47. The radiation power level control method of claim 45 wherein said power data history includes data relating to at least one of:

(i) time elapsed since said last transmission event;

(ii) duration of said last transmission event;

(iii) one or more nominal antenna SAR values of said wireless UE device;

(iv) last power level; and

(v) last average power level.

49. The radiation power level control method of claim 45 wherein said current transmission event in a usage mode comprising at least one of:

a speakerphone mode, a mode of positioning said wireless UE device near a user'"'"'s ear, a mode of placing said wireless UE device in a user'"'"'s holster, and a mode of placing said wireless UE device at a place positioned away from a user'"'"'s body.

46. The radiation power level control method of claim wherein said control action further includes at least one of (i) providing a notification to a user of said wireless UE device engaged in said current transmission event;

(ii) changing a modulation and coding scheme (MCS) used in said current transmission event;

(iii) terminating said current transmission event; and

(iv) delaying said current transmission event.

48. The radiation power level control method of claim wherein said current transmission event comprises at least one of a voice call, a data session, and an uplink event.

50. A wireless user equipment (UE) device comprising:

a storage element for storing a power data history associated with said wireless UE device, said power data history comprising data tracked over a time window relative to one or more variables;

a component configured to determine one or more Specific Absorption Rate (SAR) values during a current transmission event using said power data history, if said current transmission event involving said wireless UE device occurred within a predetermined duration from a last transmission event;

a component configured to reset said power data history if said current transmission event occurred outside said predetermined duration from said last transmission event, and to determine said one or more SAR values during said current transmission event using said reset power data history;

a component configured to effectuate a control action relative to said current transmission event, if at least one of said one or more SAR values exceeds a threshold, wherein said control action includes at least reducing a transmission power level radiating from at least one radio frequency (RF) antenna of said wireless UE device.

51. The wireless UE device of claim 50 wherein said component configured to effectuate a control action relative to said current transmission event further includes a component configured to perform at least one of:

(i) provide a notification to a user of said wireless UE device engaged in said current transmission event;

(ii) change a modulation and coding scheme (MCS) used in said current transmission event;

(iii) terminate said current transmission event; and

(iv) delay said current transmission event.

52. The wireless UE device of claim 50 wherein said component configured to reset said power data history comprises a component configured to zero out said power data history tracked over said time window.

53. The wireless UE device of claim 50 further comprising a component configured to update said power level history using data computed during said current transmission event.

54. A radiation power level control system for controlling transmission power level of a wireless user equipment (UE) device, said system comprising:

a tracking component for maintaining a history of power data for said wireless UE device, said power data comprising data tracked over a time window relative to one or more variables on a per transmission event basis;

a Specific Absorption Rate (SAR) determining module for determining one or more SAR values for said wireless UE device during a current transmission event involving said wireless UE device, wherein said SAR determining module is configured to use said history of power data if said current transmission event occurred within a predetermined duration from a last transmission event involving said wireless UE device; and

an adjustment module configured to facilitate adjusting a transmit power level of said wireless UE device if at least one of said one or more SAR values exceeds a threshold.

55. The radiation power level control system of claim 54 wherein said adjustment module is further configured to update said history of power data using data computed during said current transmission event.

56. The radiation power level control system of claim 54 further comprising a notification module for providing a notification to a user of said wireless UE device engaged in said current transmission event.

57. The radiation power level control system of claim wherein said current transmission event comprises at least one of a voice call, a data session and an uplink event involving said wireless UE device.