Method and apparatus for dormant mode support with paging

• US 20050232200A1
• Filed: 06/14/2005
• Published: 10/20/2005
• Est. Priority Date: 10/04/2002
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Watanabe, Fujio, Kawahara, Toshiro, Jeong, Moo Ryong
• Granted Patent: US 7,417,971 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 60/04 using triggered events
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and communication system for supporting dormant mode are described. In one embodiment, the communication system comprises a wireless station operable in a power savings mode and group of access points. Each group of access points comprises one or more access points with at least one group of access points having at least two access points. Ranges for the one or more access points in each of the groups define a paging area for each group, wherein one access point uses a paging channel for paging the wireless station when the wireless station is in the power savings mode and is in the paging area associated with the one access point. The wireless station performs a handoff procedure when the one access point is not in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode and does not perform a handoff procedure when the one access point is in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode.

Claims

1. A wireless station comprising:

a paging message processor to determine whether a paging area identifier has changed; and

a paging controller to associate with the one access point through a handoff procedure when the one access point is not in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode and to associate with the one access point without performing a handoff procedure when the one access point is in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode.

2. The wireless station defined in claim 1 further comprising a location manager to store information indicative of the access point most recently associated with the wireless station.

3. The wireless station defined in claim 1 further comprising a frame reception processor to extract the paging area identifier from a received paging message.

4. The wireless station defined in claim 1 wherein the paging area identifier is received from a virtual channel.

5. The wireless station defined in claim 1 wherein the paging area identifier distinctly identifies a group of access points to which an access point associated with the wireless station belongs.

6. An access point comprising:

a paging message generator to generate a paging message for a wireless station; and

a paging controller to page the wireless station using a paging channel when the wireless station is in the power savings mode and is in the paging area associated with the access point to allow the wireless station to perform a handoff procedure when the access point is not in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode and to not perform a handoff procedure when the access point is in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode.

7. The access point defined in claim 6 wherein the paging message generator determines in which beacon the paging message for the wireless station is transmitted.

8. The access point defined in claim 6 wherein the paging controller sends a signal to the wireless station having the TIMs and access point identifiers for all access points in the at least one group of access points.

9. The access point defined in claim 6 wherein the paging channel is a virtual channel.

10. The access point defined in claim 6 wherein the paging controller uses the paging channel to notify the wireless station that a message has been received for the wireless station when the wireless station was in the power savings mode.

11. The access point defined in claim 10 further comprising a buffer to buffer the message until the wireless station exits the power savings mode and receives the message.

12. The access point defined in claim 6 wherein the paging controller sends a beacon on the paging channel, the beacon containing a paging identifier distinctly identifying the group of access points to which the one access point belongs.

13. A method comprising:

detecting a group identification in the beacon broadcast of one of a plurality of access points in an access point group after a wireless station exits a power savings mode;

associating with one access point through a handoff procedure when the one access point is not in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode; and

associating with the one access point without performing a handoff procedure when the one access point is in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode.

14. The method defined in claim 13 further comprising access points in each group of access points exchanging identifiers and traffic indication maps (TIMs) for the access points with their group.

15. The method defined in claim 13 further comprising at least one access points sending a signal to the wireless station having the TIMs and access point identifiers for all access points in the at least one group of access points.

16. The method defined in claim 13 further comprising receiving the beacon on a virtual channel.

17. The method defined in claim 13 notifying the wireless station that a message has been received for the wireless station when the wireless station was in the power savings mode.

18. The method defined in claim 13 wherein the beacon contains a paging identifier distinctly identifying the group of access points to which the one access point belongs.

19. A communication system comprising:

a wireless station operable in a power savings mode; and

a plurality of groups of access points, wherein each group of access points comprises one or more access points with at least one group of access points having at least two access points, and wherein ranges for the one or more access points in each of the plurality of groups define a paging area for said each group,

wherein one access point uses a paging channel for paging the wireless station when the wireless station is in the power savings mode and is in the paging area associated with the one access point, the wireless station performing a handoff procedure when the one access point is not in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode and not performing a handoff procedure when the one access point is in the same group of access points as the access point associated with the wireless station prior to the wireless station entering the power savings mode.

20. The communication system defined in claim 19 wherein access points in each group of access points exchange identifiers and traffic indication maps (TIMs) for the access points with their group.

21. The communication system defined in claim 19 wherein at least one access point sends a signal to the wireless station having the TIMs and access point identifiers for all access points in the at least one group of access points.

22. The communication system defined in claim 19 wherein the paging channel is a virtual channel.

23. The communication system defined in claim 19 wherein the one access point uses the paging channel to notify the wireless station that a message has been received for the wireless station when the wireless station was in the power savings mode.

24. The communication system defined in claim 23 wherein the one access point buffers the message until the wireless station exits the power savings mode and receives the message.

25. The communication system defined in claim 19 wherein the one access point sends a beacon on the paging channel, the beacon containing a paging identifier distinctly identifying the group of access points to which the one access point belongs.

26. A communication system comprising:

a plurality of groups of access points, wherein each group of access points comprises one or more access points with at least one group of access points having at least two access points, each access point in said each group using a paging area identifier that is unique to said each group when broadcasting in the paging area for said each group as part of paging by access points in said each group, wherein access points in each group of access points exchange identifiers and traffic indication maps (TIMs) for the access points with their group.

27. The communication system defined in claim 26 wherein at least one access points sends a signal to the wireless station having the TIMs and access point identifiers for all access points in the at least one group of access points.

28. The communication system defined in claim 26 wherein access points in a group the paging channel is a virtual channel.

29. The communication system as claimed in claim 26 wherein the unique paging identifier comprises a unique paging area identification number.

30. The communication system as claimed in claim 26 wherein the unique paging area identification number is included in a beacon packet broadcast by the one or more access points in its corresponding group of access points.

31. The communication system as claimed in claim 26 further comprising a wireless station.

32. The communication system defined in claim 26 further comprising a wireless station operable in a power savings mode, wherein at least one access point use paging when the wireless station is in the power savings mode and is in the paging area associated with the at least one access point to notify the wireless unit that a message has been received for the wireless station.