Active set management based on mobile station battery power

• US 8,526,906 B1
• Filed: 06/04/2010
• Issued: 09/03/2013
• Est. Priority Date: 06/04/2010
• Status: Active Grant

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Oroskar, Siddharth S., Pulugurta, Srikanth, Shah, Maulik K.
• Primary Examiner(s): Lee, John J
• Application Number:
  US12/794,518
• Time in Patent Office: 1,187 Days
• Field of Search: 455/572, 455/573, 455/574, 455/127.1, 455/127.5, 455/343.1, 455/343.2, 455/343.5, 455/550.1, 455/67.11
• US Class Current: 455/343.1
• CPC Class Codes: H04W 52/0277 according to available power supply, e.g. switching off when a low battery condition is detected
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Exemplary methods and systems are disclosed herein to adjust active-set parameters based on the remaining battery life of a mobile station, generally in order to conserve battery power when the battery is low. An exemplary method involves: (a) a mobile station determining a battery-power level of the mobile station; (b) the mobile station using the determined battery-power level as a basis for setting at least one active-set parameter affecting the number of active sectors in an active set of the mobile station; and (c) the mobile station maintaining the active set according to the at least one active-set parameter. In an exemplary embodiment, the mobile station may set a maximum number of active sectors that the mobile station can include in the active set and/or parameters affecting whether a sector is included in the active set.

Claims

1. A method comprising:

(a) a mobile station determining a battery-power level of the mobile station;

(b) the mobile station using the determined battery-power level as a basis for setting at least one active-set parameter affecting the number of active sectors in an active set of the mobile station, wherein each active sector is a sector where service is provided by a radio access network; and

(c) the mobile station maintaining the active set according to the at least one active-set parameter.

2. The method of claim 1, wherein setting the at least one active-set parameter comprises setting a maximum number of active sectors that the mobile station can include in the active set of the mobile station.

3. The method of claim 2, wherein setting the maximum number of active sectors comprises setting a value of a maximum-active-sector parameter that is stored at the mobile station.

4. The method of claim 2, wherein using the determined battery-power level as a basis for setting the maximum number of active sectors comprises:

if the determined battery-power level is above a first threshold, then setting the maximum number of active sectors to an initial maximum number; and

if the determined battery-power level is below the first threshold, then setting the maximum number of active sectors to a first reduced number that is less than the initial maximum number.

5. The method of claim 4, wherein using the determined battery-power level as a basis for setting the maximum number of active sectors further comprises:

if the determined battery-power level is below a second threshold, then setting the maximum number of active sectors to a second reduced number, wherein the second threshold corresponds to a lower battery-power level than the first threshold, and wherein the second reduced number is less than the first reduced number.

6. The method of claim 2, wherein using the determined battery-power level as a basis for setting the maximum number of active sectors comprises reducing the maximum number of active sectors in response to a determination that the battery-power level is below a threshold level, the method further comprising:

making a subsequent determination that the battery-power level for the mobile station has increased to above the threshold level; and

responsive to the subsequent determination that the battery-power level is above the threshold level, increasing the maximum number of active sectors.

7. The method of claim 1, further comprising:

determining an average signal strength for one or more of the active sectors in the active set of the mobile station; and

conditioning performance of the method upon the average signal strength being greater than a threshold average signal strength.

8. The method of claim 1, further comprising:

determining signal strength for one or more active sectors in the active set of the mobile station; and

conditioning performance of the method upon at least a minimum number of the active sectors having a signal strength that is greater than a threshold signal strength.

9. The method of claim 1, wherein setting the at least one active-set parameter comprises setting at least one active-set parameter affecting whether or not a given sector is included in the active set.

10. The method of claim 9, wherein setting the at least one active-set parameter affecting whether or not a given sector is included in the active set comprises setting at least one of (a) a threshold pilot strength for addition to the active set (T_ADD), (b) a threshold difference in signal strength from an active set pilot (T_COMP), (c) a threshold pilot strength for removal from the active set (T_DROP), and (d) a time for which an active set pilot falls below T_DROP to justify removal from the active set (T_TDROP).

11. The method of claim 9, wherein using the determined battery-power level as a basis for setting at least one active-set parameter affecting whether or not a given sector is included in the active set comprises at least one of (a) setting at least one active-set parameter such that it is less likely that a given sector will be added to the active set and (b) setting at least one active-set parameter such that it is more likely that a given sector will be dropped from the active set.

12. A method comprising:

(a) a mobile station making a determination that a battery-power level for the mobile station is below a first threshold level;

(b) responsive to the determination that the battery-power level is below the first threshold level, the mobile station reducing a maximum-active-sector parameter from an initial value to a first reduced value, wherein the value of the maximum-active-sector parameter indicates a maximum number of active sectors that the mobile can include in the active set of the mobile station, and wherein each active sector is a sector where service is provided by a radio access network; and

(c) the mobile station maintaining its active set according to the first reduced value of the maximum-active-sector parameter.

13. The method of claim 12, wherein making the determination that the battery-power level for the mobile station is below the first threshold level comprises determining that the battery-power level for the mobile station is below 10% of a full battery-power level.

14. The method of claim 12, further comprising:

the mobile station making a determination that the battery-power level for the mobile station has further fallen and is below a second threshold level; and

responsive to the determination that the battery-power level is below the second threshold level, the mobile station reducing the maximum-active-sector parameter to a second reduced value.

15. The method of claim 14, wherein the first threshold level is ten percent of a fully-charged battery-power level and the second threshold level is five percent of the fully-charged battery-power level, and wherein the initial value of the maximum-active-sector parameter is six, the first reduced value of the maximum-active-sector parameter is four, and the second reduced value of the maximum-active-sector parameter is three.

16. A method comprising:

(a) a mobile station making a determination that a battery-power level for the mobile station is below a first threshold level;

(b) responsive to the determination that the battery-power level is below the first threshold level, the mobile station adjusting at least one active-set parameter affecting whether or not a given sector of a radio access network is included in the active set in effort to reduce the number of active sectors in the active set; and

(c) the mobile station maintaining its active set according to the at least one adjusted active-set parameter.

17. The method of claim 16, wherein adjusting the at least one active-set parameter affecting whether or not a given sector is included in the active set comprises at least one of (a) increasing a threshold pilot strength for addition to the active set (T_ADD), (b) increasing a threshold difference in signal strength from an active set pilot (T_COMP), (c) decreasing a threshold pilot strength for removal from the active set (T_DROP), and (d) decreasing a time for which an active set pilot falls below T_DROP to justify removal from the active set (T_TDROP).

18. The method of claim 16, further comprising:

the mobile station making a determination that the battery-power level for the mobile station has further fallen and is below a second threshold level; and

responsive to the determination that the battery-power level is below the second threshold level, the mobile station further adjusting the at least one active-set parameter affecting whether or not a given sector is included in the active set in effort to further reduce the number of active sectors in the active set.

19. A system comprising:

a tangible non-transitory computer-readable medium; and

program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to;

(a) determine a battery-power level of the mobile station;

(b) use the determined battery-power level as a basis to set at least one active-set parameter affecting the number of active sectors in an active set of the mobile station, wherein each active sector is a sector where service is provided by a radio access network; and

(c) maintain the mobile station'"'"'s active set according to the at least one active-set parameter.

20. The system of claim 19, wherein the at least one active-set parameter comprises a maximum number of active sectors that the mobile station can include in the active set of the mobile station.

21. The system of claim 20, wherein the program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to set the maximum number of active sectors comprise program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to set a maximum-active-sector parameter that is stored at the mobile station.

22. The system of claim 21, further comprising battery-power-to-active-sector correlation data stored in the tangible non-transitory computer-readable medium, wherein the battery-power-to-active-sector correlation data indicates one or more value for the maximum-active-sector parameter, each value corresponding to threshold battery-power level or range of battery-power levels.

23. The system of claim 20, wherein the program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to use the determined battery-power level as a basis to set a maximum number of active sectors comprise program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to:

if the determined battery-power level is above a first threshold, then set the maximum number of active sectors to a initial maximum number; and

if the determined battery-power level is below the first threshold, then set the maximum number of active sectors to a first reduced maximum number that is less than the initial maximum number.

24. The system of claim 23, wherein the program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to use the determined battery-power level as a basis to set a maximum number of active sectors further comprise program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to:

if the determined battery-power level is below a second threshold, then set the maximum number of active sectors to a second reduced maximum number, wherein the second threshold corresponds to a lower battery-power level than the first threshold, and wherein the second reduced maximum number is less than the first reduced maximum number.

25. The system of claim 20, wherein the maximum number of active sectors has been reduced in response to a determination that the battery-power level is below a threshold level, the system further comprising program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to:

make a subsequent determination that the battery-power level for the mobile station has increased to above the threshold level; and

responsive to the determination that the battery-power level is above the first threshold level, increase the maximum number of active sectors.

26. The system of claim 19, further comprising program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to:

receive an indication of signal strengths for the active sectors in the active set;

determine an average signal strength of the active sectors; and

condition performance of the method upon the average signal strength being greater than a threshold average signal strength.

27. The system of claim 19, further comprising program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to:

receive an indication of one or more signal strengths for one or more active sectors in the active set; and

condition (a)-(c) upon at least a minimum number of the active sectors having a signal strength that is greater than a threshold signal strength.

28. The system of claim 19, wherein the at least one active-set parameter comprises at least one active-set parameter affecting whether or not a given sector is included in the active set.

29. The system of claim 28, wherein the program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to set the at least one active-set parameter affecting whether or not a given sector is included in the active set comprise program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to set at least one of (a) a threshold pilot strength for addition to the active set (T_ADD), (b) a threshold difference in signal strength from an active set pilot (T_COMP), (c) a threshold pilot strength for removal from the active set (T_DROP), and (d) a time for which an active set pilot falls below T_DROP to justify removal from the active set (T_TDROP).

30. The system of claim 28, wherein the program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to use the determined battery-power level as a basis for setting at least one active-set parameter affecting whether or not a given sector is included in the active set comprise program instructions stored in the tangible non-transitory computer-readable medium and executable by at least one processor to (a) set at least one active-set parameter such that it is less likely that a given sector will be added to the active set and/or (b) set at least one active-set parameter such that it is more likely that a given sector will be dropped from the active set.