Active set management based on the likelihood of a mobile station roaming

• US 8,626,154 B1
• Filed: 11/05/2010
• Issued: 01/07/2014
• Est. Priority Date: 11/05/2010
• Status: Expired due to Fees

• 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): Zewdu, Meless N
• Assistant Examiner(s): Nguyen, Michael
• Application Number:
  US12/940,513
• Time in Patent Office: 1,159 Days
• Field of Search: 455/432.1, 455/435.1, 455/436, 455438-441, 455/443, 455/444
• 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:

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

the WCD using the likelihood of roaming as a basis for managing an active set of the WCD, wherein managing the active set comprises;

if the likelihood of roaming is above a first threshold, then adjusting at least one active-set parameter in an effort to reduce the probability that the WCD will be handed off to the non-preferred coverage area, wherein adjusting the at least one active-set parameter comprises setting a maximum number of active sectors that the WCD can include in the active set of the WCD to a second maximum number; and

otherwise, if the likelihood of roaming is equal to or below the first threshold, then refraining from adjusting the at least one active-set parameter in an effort to reduce a probability of a handoff to the non-preferred coverage area and setting the maximum number of active sectors to a first maximum number, wherein the second maximum number that is greater than the first maximum number.

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 adjusting the at least one active-set parameter comprises setting a value of a maximum-active-sector parameter that is stored at the WCD.

4. The method of claim 1, wherein adjusting the at least one active-set parameter 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 probability of roaming than the first threshold, and wherein the third maximum number is greater than the second maximum number.

5. The method of claim 1, wherein adjusting the at least one active-set parameter further comprises:

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

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

6. The method of claim 5, wherein setting the at least one active-set parameter affecting the number of active sectors in the active set of the WCD comprises setting at least one active-set parameter affecting whether or not a given sector is included in the active set.

7. The method of claim 6, 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).

8. The method of claim 6, 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.

9. The method of claim 6, wherein adjusting at least one active-set parameter in an effort to reduce the probability that the WCD will be handed off to the non-preferred coverage comprises:

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

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

10. A wireless-communication-device 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 probability that a wireless communication device (WCD) will be handed off from a preferred coverage area to a non-preferred coverage area, 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; and

(b) use the likelihood of roaming as a basis to manage an active set of the WCD, wherein management of the active set comprises;

(i) if the likelihood of roaming is above a first threshold, then adjusting at least one active-set parameter in an effort to reduce the probability that the WCD will be handed off to the non-preferred coverage area, wherein adjusting the at least one active-set parameter comprises setting a maximum number of active sectors that the WCD can include in the active set of the WCD to a second maximum number; and

(ii) otherwise, if the likelihood of roaming is equal to or below the first threshold, then refraining from adjusting the at least one active-set parameter in an effort to reduce a probability of a handoff to the non-preferred coverage area and setting the maximum number of active sectors to a first maximum number, wherein the second maximum number that is greater than the first maximum number.

11. The wireless-communication-device system of claim 10, wherein the program instructions stored on the non-transitory tangible computer-readable medium and executable by at least one processor to adjust the at least one active-set parameter 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 setting of the at least one active-set parameter that affects whether or not a given sector is included in the active set.

12. The wireless-communication-device system of claim 11, 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).