Mobile-station-initiated removal of a high-congestion sector from the active set

• US 8,363,622 B1
• Filed: 04/07/2010
• Issued: 01/29/2013
• Est. Priority Date: 04/07/2010
• Status: Expired due to Fees

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Oroskar, Siddharth, Pulugurta, Srikanth, Shah, Maulik
• Primary Examiner(s): HAN, CLEMENCE S
• Application Number:
  US12/756,041
• Time in Patent Office: 1,028 Days
• Field of Search: None
• US Class Current: 370/332
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection

Abstract

Exemplary methods and systems may be used by a mobile station to request that a sector be removed from its active set, and by a radio access network (RAN) to facilitate such a request. An exemplary method involves (a) a mobile station receiving a congestion indicator in each active sector of an active set of the mobile station, wherein the congestion indicators are received from a RAN; (b) the mobile station using the received congestion indicators as a basis for selecting at least one high-congestion sector from the active set; and (c) the mobile station providing an indication of the at least one high-congestion sector to the RAN. Further, the mobile station may perform steps (b)-(c) in response to a determination that the battery power for the mobile station is below the threshold level.

Claims

1. A method comprising:

(a) a mobile station receiving a congestion indicator in each active sector of an active set of the mobile station, wherein the congestion indicators are received from a radio access network (RAN);

(b) the mobile station using the received congestion indicators as a basis for selecting at least one high-congestion sector from the active set; and

(c) the mobile station providing an indication of the at least one high-congestion sector to the RAN.

2. The method of claim 1, further comprising:

the mobile station making a determination that battery power for the mobile station is below a threshold level; and

the mobile station performing (b)-(c) in response to the determination that the battery power for the mobile station is below the threshold level.

3. The method of claim 1, further comprising:

the mobile station making a determination that the mobile station is substantially stationary; and

the mobile station performing (b)-(c) in response to the determination that the mobile station is substantially stationary.

4. The method of claim 1, wherein the mobile station receives the congestion indicator in a handoff direction message (HDM) from the RAN.

5. The method of claim 1, wherein the received congestion indicator for each active sector is based on at least one of:

(a) the paging channel occupancy (PCO) in the sector, (b) the access channel occupancy (ACO) in the sector, and (c) Walsh-code usage on forward-link in the sector.

6. The method of claim 1, wherein each received congestion indicator indicates a relative level of congestion in the corresponding active actor, and wherein using the received congestion indicators as a basis for selecting the at least one high-congestion sector from the active set comprises:

selecting an active sector having the highest relative level of congestion as the at least one high-congestion sector.

7. The method of claim 1, wherein providing an indication of the at least one high-congestion sector to the RAN comprises sending an Active Sector Removal Request (ASR-Request) to the RAN via a reverse-link traffic channel, wherein the ASR-Request identifies the at least one high-congestion sector.

8. The method of claim 7, wherein the ASR-Request further comprises a priority indicator.

9. The method of claim 7, wherein the ASR-Request is sent in response to a determination that a battery level of the mobile station has dropped below a threshold level.

10. The method of claim 1, further comprising, the mobile station refraining from adding the at least one high-congestion sector back into the active set until the mobile station receives a Reconnect Authorization Message (RCNA-Message) from the RAN identifying the high-congestion sector.

11. A method comprising:

(a) a radio access network (RAN) transmitting a congestion indicator in each of a plurality of sectors, wherein the plurality of sectors includes one or more active sectors from an active set of a mobile station;

(b) the RAN receiving from the mobile station, an indication of at least one high-congestion sector from the active set, wherein the at least one high-congestion sector has been selected based at least in part on the congestion indicators in the active sectors; and

(c) the RAN determining whether to remove the at least one high-congestion sector from the active set.

12. The method of claim 11, further comprising the RAN initially determining the congestion indicator in each of the plurality of sectors.

13. The method of claim 12, wherein determining the congestion indicator in each of the plurality of sectors comprises:

using at least one of;

(a) the paging channel occupancy (PCO) in the sector, (b) the access channel occupancy (ACO) in the sector, and (c) Walsh-code usage on forward-link in the sector, as a basis for determining the congestion indicator in the sector.

14. The method of claim 11, wherein the RAN receives the indication of the at least one high-congestion sector in an Active Sector Removal Request (ASR-Request) from the mobile station.

15. The method of claim 11, wherein determining whether to remove the at least one high-congestion sector from the active set comprises:

comparing a congestion level in the high-congestion sector to a threshold level of congestion; and

if the congestion level in the high-congestion sector is greater than the threshold level, then removing the high-congestion sector from the active set.

16. The method of claim 11, wherein determining whether to remove the at least one high-congestion sector from the active set comprises:

automatically removing the high-congestion sector from the active set in response to receiving the indication of at least one high-congestion sector.

17. A system comprising:

a tangible computer-readable medium; and

program instructions stored in the tangible computer-readable medium that, when executed by a processor, cause a mobile station to;

(a) receive a congestion indicator in each active sector of an active set of the mobile station, wherein the congestion indicators are received from a radio access network (RAN);

(b) use the received congestion indicators as a basis to select at least one high-congestion sector from the active set; and

(c) provide an indication of the at least one high-congestion sector to the RAN.

18. The system of claim 17, further comprising program instructions stored in the tangible computer-readable medium that, when executed by a processor, cause a mobile station to:

make a determination that battery power of the mobile station is below a threshold level; and

perform (b)-(c) in response to the determination that the battery power of the mobile station is below the threshold level.

19. The method of claim 17, wherein the indication of the at least one high-congestion comprises an Active Sector Removal Request (ASR-Request) that is provided to the RAN via a reverse-link traffic channel, wherein the ASR-Request identifies the at least one high-congestion sector and includes a priority indicator.

20. A method comprising:

(a) a mobile station initially operating in a first scanning mode, wherein operation in the first scanning mode comprises the mobile station scanning all active sectors in an active set of the mobile station;

(b) a mobile station receiving a congestion indicator for each active sector in an active set of the mobile station, wherein the congestion indicators are received from a radio access network (RAN), and wherein each received congestion indicator indicates a level of congestion in the corresponding active actor;

(c) the mobile station selecting at least one high-congestion sector as a transparent sector, the selected high-congestion sector having the highest level of congestion relative to the other active sectors; and

(d) the mobile station operating in a second scanning mode, wherein operation in the second scanning mode comprises the mobile station scanning a subset of the sectors in the active set, wherein the subset excludes the at least one high congestion sector that is selected as a transparent sector.