Power saving method for a mobile terminal

• US 20030104849A1
• Filed: 11/27/2002
• Published: 06/05/2003
• Est. Priority Date: 11/30/2001
• Status: Active Grant

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Arimitsu, Kazuhiro
• Granted Patent: US 7,146,151 B2
• Time in Patent Office: Days
• US Class Current: 455/574
• CPC Class Codes: H04B 2201/70709 with discontinuous detection
• CPC Class Codes: H04W 52/0261 managing power supply demand, e.g. depending on battery level
• CPC Class Codes: H04W 52/029 reducing the clock frequency of the controller
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a CDMA mobile terminal, the power supply voltage of the mobile terminal is compared with a first threshold voltage, and frequency monitor is performed at a normal rate if the power supply voltage is higher than the first threshold voltage, and frequency monitor is performed at 1/N of the normal rate if the power supply voltage is lower than the first threshold voltage, where N is equal to or greater than 2. Additionally, the power level of an RF signal received by the mobile terminal is compared with a first reference level, and frequency monitor is performed at the normal rate if the power level of the RF signal is lower than the first reference level, and frequency monitor is performed at 1/N of the normal rate if the power level of the RF signal is higher than the first reference level.

Claims

1. A power saving method for a mobile terminal, comprising the steps of:

a) comparing a power supply voltage of the mobile terminal with a first threshold voltage;

b) performing a frequency monitor at a normal rate if the power supply voltage is higher than the first threshold voltage; and

c) performing a frequency monitor at 1/N of said normal rate if the power supply voltage is lower than the first threshold voltage, where N is equal to or greater than 2.

2. The power saving method of claim 1, wherein step (c) comprises the steps of:

comparing the power supply voltage with a second threshold voltage which is lower than the first threshold voltage; and

performing a frequency monitor at 1/N of said normal rate until said power supply voltage drops below said second threshold voltage.

3. The power saving method of claim 2, further comprising the step of disabling said frequency monitor if the power supply voltage is lower than said second threshold voltage.

4. The power saving method of claim 3, further comprising the steps of:

comparing the power supply voltage with a third threshold voltage which is higher than said first threshold voltage; and

performing a frequency monitor at said normal rate when the power supply voltage is higher than said third threshold voltage.

5. The power saving method of claim 1, wherein step (c) comprises the step of performing said frequency monitor on a varying number of different frequencies at 1/N of said normal rate, depending on different magnitudes of the power supply voltage.

6. The power saving method of claim 1, 2, 3, 4 or 5, further comprising the steps of:

A) comparing a power level of an RF signal received by the mobile terminal with a first reference level;

B) performing a frequency monitor at said normal rate if the power level of the RF signal is lower than the first reference level; and

C) performing a frequency monitor at 1/N of said normal rate if the power level of the RF signal is higher than the first reference level.

7. The power saving method of claim 6, wherein step (C) comprises the steps of:

comparing said power level with a second reference level which is lower than the first reference level, and

continuing the frequency monitor at 1/N of said normal rate until said power level drops below said second reference level.

8. The power saving method of claim 7, further comprising the step of disabling said frequency monitor if the power level of the received RF signal is lower than said second reference level.

9. The power saving method of claim 8, further comprising the steps of:

comparing the power level of the received RF signal with a third reference level which is higher than said first reference level; and

performing a frequency monitor at said normal rate when the power level of the received RF signal is higher than said third reference level.

10. The power saving method of claim 1, 2, 3, 4 or 5, further comprising the steps of:

A) comparing a travelling speed of the mobile terminal with a first reference speed; and

B) performing a frequency monitor at said normal rate if the travelling speed is lower than the first reference speed; and

C) performing a frequency monitor at 1/N of said normal rate if the travelling speed is higher than the first reference speed.

11. The power saving method of claim 10, wherein step (C) comprises the steps of:

comparing said travelling speed with a second reference speed which is lower than the first reference speed; and

continuing the frequency monitor at 1/N of said normal rate until said travelling speed drops below said second reference speed.

12. The power saving method of claim 11, further comprising the step of disabling said frequency monitor if the travelling speed is lower than said second reference speed.

13. The power saving method of claim 12, further comprising the steps of:

comparing said travelling speed with a third reference speed which is higher than the first reference speed; and

performing said frequency monitor at said normal rate when the travelling speed is higher than said third reference speed.

14. The power saving method of claim 1, 2, 3, 4 or 5, further comprising the steps of:

A) performing a frequency monitor on a first plurality of cell-sites if the power supply voltage is higher than the first threshold voltage; and

B) performing a frequency monitor on a second plurality of cell-sites if the power supply voltage is lower than the first threshold voltage, said second plurality of cell-sites are smaller in number than said first plurality of cell-sites.

15. The power saving method of claim 14, wherein step (B) comprises the steps of:

comparing said power supply voltage with a second threshold voltage which is higher than said first threshold voltage; and

continuing the frequency monitor on said second plurality of cell-sites if said power supply voltage becomes higher than said second threshold voltage.

16. The power saving method of claim 15, further comprising the step of performing said frequency monitor on said first plurality of cell-sites if said power supply voltage is higher than said second threshold voltage.

28. The power saving method of claim 1, 17, 21 or 25, wherein said mobile terminal is a CDMA mobile terminal.

17. A power saving method for a mobile terminal, comprising the steps of:

a) comparing a power level of an RF signal received by the mobile terminal with a first reference level;

b) performing a frequency monitor at a normal rate if the power level of the RF signal is lower than the first reference level; and

c) performing a frequency monitor at 1/N of said normal rate if the power level of the RF signal is higher than the first reference level, where N is equal to or greater than 2.

18. The power saving method of claim 17, wherein step (c) comprises the steps of:

comparing said power level with a second reference level which is lower than the first reference level; and

continuing the frequency monitor at 1/N of said normal rate until said power level drops below said second reference level.

19. The power saving method of claim 18, further comprising the step of disabling said frequency monitor if the power level of the received RF signal is lower than said second reference level.

20. The power saving method of claim 19, further comprising the steps of:

comparing the power level of the received RF signal with a third reference level which is higher than said first reference level; and

performing said frequency monitor at said normal rate when the power level of the received RF signal is higher than said third reference level.

21. A power saving method for a mobile terminal, comprising the steps of:

a) comparing a travelling speed of the mobile terminal with a first reference speed; and

b) performing a frequency monitor at a normal rate if the travelling speed is lower than the first reference speed; and

c) performing a frequency monitor at 1/N of said normal rate if the travelling speed is higher than the first reference speed, where N is equal to or greater than 2.

22. The power saving method of claim 21, wherein step (c) comprises the steps of:

comparing said travelling speed with a second reference speed which is lower than the first reference speed; and

continuing the frequency monitor at 1/N of said normal rate until said travelling speed drops below said second reference speed.

23. The power saving method of claim 22, further comprising the step of disabling said frequency monitor if the travelling speed is lower than said second reference speed.

24. The power saving method of claim 23, further comprising the steps of:

comparing said travelling speed with a third reference speed which is higher than the first reference speed; and

performing a frequency monitor at said normal rate when the travelling speed is higher than said third reference speed.

25. A power saving method for a mobile terminal, comprising the steps of:

a) comparing a power supply voltage of the mobile terminal with a first threshold voltage; and

b) performing a frequency monitor on a first plurality of cell-sites if the power supply voltage is higher than the first threshold voltage; and

c) performing a frequency monitor on a second plurality of cell-sites if the power supply voltage is lower than the first threshold voltage, said second plurality of cell-sites are smaller in number than said first plurality of cell-sites.

26. The power saving method of claim 25, wherein step (c) comprises the steps of:

comparing said power supply voltage with a second threshold voltage which is higher than said first threshold voltage; and

continuing the frequency monitor on said second plurality of cell-sites if said power supply voltage becomes higher than said second threshold voltage.

27. The power saving method of claim 26, further comprising the step of performing said frequency monitor on said first plurality of cell-sites if said power supply voltage is higher than said second threshold voltage.

29. A mobile terminal comprising:

receiver circuitry for establishing a wireless link with a communications network;

monitor circuitry connected to the receiver circuitry for performing a frequency monitor by scanning one or more frequencies specified by the network other than the frequency of said wireless link; and

control circuitry for comparing a power supply voltage of the mobile terminal with a first threshold voltage and controlling said monitor circuitry to perform said frequency monitor at a normal rate if the power supply voltage is higher than the first threshold voltage and to perform said frequency monitor at 1/N of said normal rate if the power supply voltage is lower than the first threshold voltage, where N is equal to or greater than 2.

30. The mobile terminal of claim 29, wherein said control circuitry compares the power supply voltage with a second threshold voltage which is lower than the first threshold voltage and controls said frequency monitor to perform said frequency monitor at 1/N of said normal rate until said power supply voltage drops below said second threshold voltage.

31. The mobile terminal of claim 30, wherein said control circuitry disables said monitor circuitry if the power supply voltage is lower than said second threshold voltage.

32. The mobile terminal of claim 31, wherein said control circuitry compares the power supply voltage with a third threshold voltage which is higher than said first threshold voltage and controls said monitor circuitry to perform said frequency monitor at said normal rate when the power supply voltage is higher than said third threshold voltage.

33. The mobile terminal of claim 29, wherein the control circuitry controls said monitor circuitry to perform said frequency monitor on a varying number of different frequencies at 1/N of said normal rate, depending on different magnitudes of the power supply voltage.

34. The mobile terminal of claim 29, 30, 31, 32 or 33, wherein said control circuitry is arranged to:

compare a power level of an RF signal received by the receiver circuitry with a first reference level; and

control said monitor circuitry to perform said frequency monitor at said normal rate if the power level of the RF signal is lower than the first reference level and at 1/N of said normal rate if the power level of the RF signal is higher than the first reference level.

35. The mobile terminal of claim 34, wherein said control circuitry is arranged to:

compare said power level with a second reference level which is lower than the first reference level; and

control said monitor circuitry to continue the frequency monitor at 1/N of said normal rate until said power level drops below said second reference level.

36. The mobile terminal of claim 35, wherein said control circuitry disables said monitor circuitry if the power level of the received RF signal is lower than said second reference level.

37. The mobile terminal of claim 36, wherein said control circuitry compares the power level of the received RF signal with a third reference level which is higher than said first reference level and controls the monitor circuitry to perform said frequency monitor at said normal rate when the power level of the received RF signal is higher than said third reference level.

38. The mobile terminal of claim 29, 30, 31, 32 or 33, wherein said control circuitry is arranged to:

compare a travelling speed of the mobile terminal with a first reference speed; and

control said monitor circuitry to perform said frequency monitor at said normal rate if the travelling speed is lower than the first reference speed; and

at 1/N of said normal rate if the travelling speed is higher than the first reference speed.

39. The mobile terminal of claim 38, wherein said control circuitry is arranged to:

compare said travelling speed with a second reference speed which is lower than the first reference speed; and

control said monitor circuitry to continue the frequency monitor at 1/N of said normal rate until said travelling speed drops below said second reference speed.

40. The mobile terminal of claim 39, further comprising the step of disabling said frequency monitor if the travelling speed is lower than said second reference speed.

41. The mobile terminal of claim 40, wherein said control circuitry is arranged to:

compare said travelling speed with a third reference speed which is higher than the first reference speed; and

control said monitor circuitry to perform said frequency monitor at said normal rate when the travelling speed is higher than said third reference speed.

42. The mobile terminal of claim 29, 30, 31, 32 or 33, wherein said control circuitry controls said monitor circuitry to perform said frequency monitor on a first plurality of cell-sites if the power supply voltage is higher than the first threshold voltage, and to perform said frequency monitor on a second plurality of cell-sites if the power supply voltage is lower than the first threshold voltage, said second plurality of cell-sites are smaller in number than said first plurality of cell-sites.

43. The mobile terminal of claim 42, wherein said control circuitry is arranged to:

compare said power supply voltage with a second threshold voltage which is higher than said first threshold voltage; and

control said monitor circuitry to continue the frequency monitor on said second plurality of cell-sites if said power supply voltage becomes higher than said second threshold voltage.

44. The mobile terminal of claim 43, wherein said control circuitry controls said monitor circuitry to perform said frequency monitor on said first plurality of cell-sites if said power supply voltage is higher than said second threshold voltage.

56. The mobile terminal of claim 29, 45, 49 or 53, wherein said receiver circuitry is a CDMA receiver.

45. A mobile terminal comprising:

receiver circuitry for establishing a wireless link with a communications network;

monitor circuitry connected to the receiver circuitry for performing a frequency monitor by scanning one or more frequencies specified by the network other than the frequency of said wireless link; and

control circuitry for comparing a power level of an RF signal received by the receiver circuitry with a first reference level, controlling said monitor circuitry to perform a frequency monitor at a normal rate if the power level of the RF signal is lower than the first reference level and at 1/N of said normal rate if the power level of the RF signal is higher than the first reference level, where N is equal to or greater than 2.

46. The mobile terminal of claim 45, wherein the control circuitry compares said power level with a second reference level which is lower than the first reference level and controls said monitor circuitry to continue the frequency monitor at 1/N of said normal rate until said power level drops below said second reference level.

47. The mobile terminal of claim 46, wherein said control circuitry disables said frequency monitor if the power level of the received RF signal is lower than said second reference level.

48. The mobile terminal of claim 47, wherein said control circuitry compares the power level of the received RF signal with a third reference level which is higher than said first reference level and controls said monitor circuitry to perform said frequency monitor at said normal rate when the power level of the received RF signal is higher than said third reference level.

49. A mobile terminal comprising:

receiver circuitry for establishing a wireless link with a communications network;

monitor circuitry connected to the receiver circuitry for performing a frequency monitor by scanning one or more frequencies specified by the network other than the frequency of said wireless link; and

control circuitry for comparing a travelling speed of the mobile terminal with a first reference speed and performing a frequency monitor at a normal rate if the travelling speed is lower than the first reference speed and at 1/N of said normal rate if the travelling speed is higher than the first reference speed, where N is equal to or greater than 2.

50. The mobile terminal of claim 49, wherein said control circuitry compares said travelling speed with a second reference speed which is lower than the first reference speed and controls said monitor circuitry to continue the frequency monitor at 1/N of said normal rate until said travelling speed drops below said second reference speed.

51. The mobile terminal of claim 50, wherein said control circuitry disables said frequency monitor if the travelling speed is lower than said second reference speed.

52. The mobile terminal of claim 51, wherein said control circuitry compares said travelling speed with a third reference speed which is higher than the first reference speed and controls said monitor circuitry to perform said frequency monitor at said normal rate when the travelling speed is higher than said third reference speed.

53. A mobile terminal comprising:

receiver circuitry for establishing a wireless link with a communications network;

monitor circuitry connected to the receiver circuitry for performing a frequency monitor by scanning one or more frequencies; and

control circuitry for comparing a power supply voltage of the mobile terminal with a first threshold voltage, and controlling said monitor circuitry to perform a frequency monitor on a first plurality of cell-sites if the power supply voltage is higher than the first threshold voltage and on a second plurality of cell-sites if the power supply voltage is lower than the first threshold voltage, said second plurality of cell-sites are smaller in number than said first plurality of cell-sites.

54. The mobile terminal of claim 53, wherein said control circuitry compares said power supply voltage with a second threshold voltage which is higher than said first threshold voltage and controls said monitor circuitry to continue said frequency monitor on said second plurality of cell-sites if said power supply voltage becomes higher than said second threshold voltage.

55. The mobile terminal of claim 54, wherein said control circuitry controls said monitor circuitry to perform said frequency monitor on said first plurality of cell-sites if said power supply voltage is higher than said second threshold voltage.