Active Set Management Based on the Likelihood of a Mobile Station Roaming

• US 20140120908A1
• Filed: 12/03/2013
• Published: 05/01/2014
• Est. Priority Date: 11/05/2010
• 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.
• Granted Patent: US 9,807,586 B2
• Time in Patent Office: Days
• US Class Current: 455/432.1
• CPC Class Codes: H04W 36/008375 based on historical data
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/326 by proximity to another entity
• CPC Class Codes: H04W 8/02 Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks

Abstract

In one aspect, an exemplary method involves a WCD: (i) determining a likelihood of roaming, wherein the likelihood of roaming indicates a likelihood that the WCD will be handed off from a preferred coverage area to a non-preferred coverage area; and (ii) using the likelihood of roaming as a basis for managing an active set of the WCD. In particular, the WCD may manage its active set by setting at least one active-set parameter affecting the number of active sectors in an active set of the WCD, and then maintaining its active set according to the setting of the at least one active-set parameter. According to an exemplary embodiment, a WCD will make an effort to increase the number of sectors in its active set when the likelihood of roaming is greater, and vice versa.

Claims

1. A method comprising:

determining a likelihood of roaming, wherein the likelihood of roaming indicates a likelihood that a wireless communication device (WCD) will be handed off from a preferred coverage area to a non-preferred coverage area, and wherein the WCD determines the likelihood of roaming; and

using, by the WCD, the likelihood of roaming as a basis for managing an active set of the WCD.

2. The method of claim 1, wherein determining the likelihood of roaming comprises receiving an indication of the likelihood of roaming from a radio access network.

3. The method of claim 1, wherein the preferred coverage area is operated by a home service provider, and wherein the non-preferred coverage area is operated by another service provider that is a roaming partner of the home service provider.

4. The method of claim 1, wherein using the likelihood of roaming as a basis for managing an active set of the WCD comprises setting a maximum number of active sectors that the WCD can include in the active set of the WCD.

5. The method of claim 4, wherein setting the maximum number of active sectors comprises setting a value of a maximum-active-sector parameter that is stored at the WCD.

6. The method of claim 4, wherein setting the maximum number of active sectors comprises:

if the likelihood of roaming is below a first threshold, then setting the maximum number of active sectors to a first maximum number; and

if the likelihood of roaming is above the first threshold, then setting the maximum number of active sectors to a second maximum number that is greater than the first maximum number.

7. The method of claim 6, wherein setting the maximum number of active sectors further comprises:

if the likelihood of roaming is above a second threshold, then setting the maximum number of active sectors to a third maximum number, wherein the second threshold corresponds to a greater likelihood of roaming than the first threshold, and wherein the third maximum number is greater than the second maximum number.

8. The method of claim 1, wherein managing the active set of the WCD comprises:

setting at least one active-set parameter affecting the number of active sectors in an active set of the WCD; and

maintaining the active set according to the at least one active-set parameter.

9. The method of claim 8, 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 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 affecting a probability that a given sector will be added to the active set, (b) setting at least one active-set parameter affecting a probability that a given active sector will be kept in the active set, and (c) setting at least one active-set parameter affecting a probability that a given active sector will be dropped from the active set.

12. The method of claim 9, wherein using the likelihood of roaming as a basis for setting the at least one active-set parameter comprises:

determining whether or not the likelihood of roaming is above a threshold;

if the likelihood of roaming is above the threshold, then at least one of (a) setting at least one active-set parameter in an effort to increase a probability that a given sector will be added to the active set, (b) setting at least one active-set parameter in an effort to increase a probability that a given active sector will be kept in the active set, and (c) setting at least one active-set parameter in an effort to decrease a probability that a given active sector will be dropped from the active set; and

if the likelihood of roaming is below the threshold, then setting the at least one active-set parameter to a default setting.

13. A system comprising:

a non-transitory computer-readable medium; and

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

(a) determine a likelihood of roaming, wherein the likelihood of roaming indicates a likelihood that a wireless communication device (WCD) will be handed off from a preferred coverage area to a non-preferred coverage area; and

(b) use the likelihood of roaming as a basis to manage an active set of the WCD.

14. The system of claim 13, wherein the program instructions stored on the non-transitory tangible computer-readable medium and executable by at least one processor to use the likelihood of roaming as a basis to manage an active set of the WCD comprise program instructions stored on the non-transitory tangible computer-readable medium and executable by at least one processor to set a maximum number of active sectors that the WCD can include in the active set of the WCD.

15. The system of claim 13, wherein the program instructions stored on the non-transitory tangible computer-readable medium and executable by at least one processor to manage the active set of the WCD comprise program instructions stored on the non-transitory tangible computer-readable medium and executable by at least one processor to:

set at least one active-set parameter that affects whether or not a given sector is included in the active set; and

maintain the active set according to the at least one active-set parameter.

16. The system of claim 15, wherein the at least one active-set parameter that affects whether or not a given sector is included in the active set comprises 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).

17. The system of claim 13, wherein the program instructions stored on the non-transitory tangible computer-readable medium and executable by at least one processor to manage the active set of the WCD comprise program instructions stored on the non-transitory tangible computer-readable medium and executable by at least one processor to:

determine whether or not the likelihood of roaming is above a predetermined threshold;

if the likelihood of roaming is above the predetermined threshold, then send the WCD an active-set management message comprising an indication to the WCD to adjust at least one active-set parameter, wherein the at least one active-set parameter affects the number of active sectors in an active set of the WCD; and

if the likelihood of roaming is below the predetermined threshold, then refrain from sending the active-set management message comprising the indication to the WCD to adjust the at least one active-set parameter.

18. A method comprising:

determining a likelihood of roaming, wherein the likelihood of roaming indicates a likelihood that a wireless communication device (WCD) that is operating in a preferred coverage area of a radio access network (RAN) will be handed off from the preferred coverage area to a non-preferred coverage area, and wherein the likelihood of roaming is determined by the RAN, and

using the likelihood of roaming for the WCD as a basis for managing an active set of the WCD.

19. The method of claim 18, further comprising:

determining, by the RAN, that the WCD has traveled to a second preferred coverage area of the RAN;

re-determining the likelihood of roaming, wherein the re-determined likelihood of roaming indicates a likelihood that the WCD will be handed off from the second preferred coverage area to a non-preferred coverage area; and

using the re-determined likelihood of roaming for the WCD as a basis for managing the active set of the WCD.

20. The method of claim 18, wherein managing the active set of the WCD comprises:

determining whether or not the likelihood of roaming for the WCD is above a predetermined threshold;

if the likelihood of roaming for the WCD is above the predetermined threshold, then sending the WCD an active-set management message comprising an indication to the WCD to adjust at least one active-set parameter, wherein the at least one active-set parameter affects the number of active sectors in an active set of the WCD; and

if the likelihood of roaming for the WCD is below the predetermined threshold, then refraining from sending the active-set management message comprising the indication to the WCD to adjust the at least one active-set parameter.

21. The method of claim 20, further comprising:

determining that the WCD has traveled to a second preferred coverage area of the RAN;

re-determining the likelihood of roaming, wherein the re-determined likelihood of roaming indicates a likelihood that the WCD will be handed off from the second preferred coverage area to a non-preferred coverage area; and

if the RAN previously sent the active-set management message comprising the indication to the WCD to adjust the at least one active-set parameter, then;

(a) if the re-determined likelihood of roaming for the WCD is above the predetermined threshold, then allowing the WCD to continue to operate according to the active-set management message comprising the indication to the WCD to adjust the at least one active-set parameter; and

(b) if the re-determined likelihood of roaming for the WCD is below the predetermined threshold, then sending an active-set management message comprising the indication to the WCD to re-adjust the at least one active-set parameter;

if the RAN previously refrained from sending the active-set management message comprising the indication to the WCD to adjust the at least one active-set parameter, then;

(a) if the re-determined likelihood of roaming for the WCD is above the predetermined threshold, then sending the active-set management message comprising the indication to the WCD to adjust the at least one active-set parameter;

(b) if the re-determined likelihood of roaming for the WCD is below the predetermined threshold, then again refraining from sending the active-set management message comprising the indication to the WCD to adjust the at least one active-set parameter.