Method and apparatus for dormant mode support with paging

• US 20060155860A1
• Filed: 01/19/2006
• Published: 07/13/2006
• Est. Priority Date: 01/28/2002
• 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, Miki, Toshio, Funato, Daichi
• Granted Patent: US 7,610,053 B2
• Time in Patent Office: Days
• US Class Current: 709/228
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• 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: H04W 76/20 Manipulation of established connections
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Apparatuses and methods are disclosed herein for implementing dormant mode with paging in a WLAN. Power savings in the computing device and reduction in traffic across the network are achieved by requiring a computing device to inform the WLAN of its location only when it crosses a paging area boundary or is to receive IP traffic. Dormant mode with paging is implemented in a protocol that supports dormant functionality and paging functionality but does not itself provide methods or standards for implementing such functionality, such as the IEEE 802.11. The methods and apparatuses disclosed herein provide the methods needed to implement dormant mode with paging in such a protocol. Generally, the methods and apparatuses for implementing dormant mode with paging basically include (1) establishing paging areas; (2) communicating access group information to a computing device; and (3) locating a computing device.

Claims

1. A method for establishing a plurality of paging areas in a WLAN, wherein the WLAN comprises a plurality of access points, comprising:

forming a plurality of access point groups, wherein each of the plurality of access point groups is formed from a subset of the plurality of access points, uses a tree structured distributed grouping model, and defines a paging area;

establishing a protocol for communications among the plurality of access points; and

establishing a protocol for manipulating access point groups.

2. A method for establishing a plurality of paging areas in a WLAN, as claimed in claim 1, further comprising, assigning each of the plurality of access point groups a unique paging area identification number and having each of the access points in each of the plurality of access point groups broadcast the paging area identification number associated with each access point'"'"'s access point group throughout each access point'"'"'s access point group.

3. A method for establishing a plurality of paging areas in a WLAN, as claimed in claim 1, wherein forming the plurality of access point groups comprises the steps of:

assigning at least one role to each of the access points in the access point group, wherein the roles comprise master and slave; and

associating each access point assigned the master role with at least one access point assigned the slave role and associating each access point assigned the slave role with exactly one access point assigned the master role.

4. A method for establishing a plurality of paging areas in a WLAN, as claimed in claim 1, wherein the protocol established for communications among the plurality of access points is an IEEE Inter Access Point Protocol.

5. A method for establishing a plurality of paging areas in a WLAN, as claimed in claim 1, wherein establishing a protocol for manipulating access point groups comprises modifying and providing an IEEE Inter Access Point Protocol.

6. A method for establishing a plurality of paging areas in a WLAN, as claimed in claim 5, wherein modifying the IEEE Inter Access Point Protocol comprises adding a join operation, a leave operation, a group merge operation, a group prune operation and a group devolution operation.

7. A method for establishing a plurality of paging areas in a WLAN, wherein the WLAN enables dormant mode with paging and comprises a plurality of access points, comprising:

forming a plurality of access point groups, wherein each of the plurality of access point groups is formed from a subset of the plurality of access points, has a tree structured distributed grouping model as the structure, and defines a paging area, comprising;

assigning at least one role to each of the access points in the access point group, wherein the roles comprise master and slave; and

associating each access point assigned the master role with at least one access point assigned the slave role and associating each access point assigned the slave role with exactly one access point assigned the master role;

the protocol established for communications among the plurality of access points is an IEEE Inter Access Point-Protocol;

establishing a protocol for manipulating access point groups comprises modifying the IEEE Inter Access Point Protocol by adding a join operation, a leave operation, a group merge operation, a group prune operation and a group devolution operation;

assigning each of the plurality of access point groups a unique paging area identification number; and

having each of the access points in each of the plurality of access point groups broadcast the paging area identification number associated with each access point'"'"'s access point group throughout each access point'"'"'s access point group.

8-10. -10. (canceled)

11. A method for synchronizing a beacon timing of a first access point with a beacon timing of a second access point wherein the first and second access points are in an access point group in a WLAN, comprising:

calculating the difference between the beacon timing of the first access point and the beacon timing of the second access point to ascertain a beacon timing difference, wherein the calculating is performed by a computing device;

communicating the beacon timing difference from the computing device to the second access point and the first access point; and

adjusting the beacon timing of either the first access point or the second access point so that the beacon timing of the either the first access point or the second access point equals the beacon timing of the other of the first access point or the second access point.

12. A method for synchronizing a beacon timing of a first access point with a beacon timing of a second access point, as claimed in claim 11, wherein calculating the difference between the beacon timing of the first access point and the beacon timing of the second access point to ascertain a beacon timing difference, comprises the steps of:

while the computing device is within a range of the first access point, periodically shifting the computing device into an active mode to detect a first access point beacon broadcast at least one predetermined time for a predetermined time interval, wherein the at least one predetermined time corresponds to beacon timing of the first access point;

moving the computing device from within the range of the first access point to within a range of the second access point;

while the computing device is within the range of the second access point, periodically shifting the computing device into the active mode to detect a second access point beacon broadcast at one of the at least one predetermined times for a time interval, wherein the time interval ends when the computing device detects the second access point beacon broadcast; and

subtracting the one of the at least one predetermined times from the time interval to calculate the beacon timing difference.

13. A method for synchronizing a beacon timing of a first access point a beacon timing of a second access point, as claimed in claim 12, wherein communicating the beacon timing difference from the computing device to the second access point and the first access point, comprises the steps of:

the computing device communicating the beacon timing difference to the second access point;

the second access point identifying the first access point;

the second access point communicating the beacon timing difference to the first access point.

14. A method for synchronizing a beacon timing of a first access point with a beacon timing of a second access point, as claimed in claim 11, wherein adjusting the beacon timing of either the first access point or the second access point so that it equals the beacon timing of the other of the first access point or the second access point, comprises the steps of:

if either the first access point or the second access point is a master of the other of the first access point or the second access point, wherein the other of the first access point or the second access point is a slave of the master access point, adjusting the beacon timing of the slave access point to the beacon timing of the master access point; and

if neither the first access point or the second access point is a master of the other of the first access point or the second access point, determining a common master access point and adjusting the beacon timing of the first access point and the beacon timing of the second access point to a beacon timing of the common master access point.

15. A method for synchronizing a beacon timing of a first access point with a beacon timing of a second access point wherein the first and second access points are in an access point group in a WLAN, comprising:

calculating the difference between the beacon timing of the first access point and the beacon timing difference of the second access point to ascertain a beacon timing difference, wherein the calculating is performed by a computing device, comprising;

while the computing device is within a range of the first access point, periodically shifting the computing device into an active mode to detect a first access point beacon broadcast at least one predetermined time for a predetermined time interval, wherein the at least one predetermined time corresponds to a beacon timing of the first access point;

moving the computing device from within the range of the first access point to within a range of the second access point;

while the computing device is within the range of the second access point, periodically shifting the computing device into the active mode to detect a second access point beacon broadcast at one of the at least one predetermined times for a time interval, wherein the time interval ends when the computing device detects the beacon broadcast of the second access point; and

subtracting the one of the at least one predetermined times from the time interval to calculate the beacon timing difference;

communicating the beacon timing difference from the computing device to the second access point and the first access points, comprising;

the computing device communicating the beacon timing difference to the second access point;

the second access point identifying the first access point;

the second access point communicating the beacon timing difference to the first access point; and

adjusting the beacon timing of either the first access point or the second access point so that the beacon timing of either the first access point or the second access point equals the beacon timing of the other of the first access point or the second access point, comprising;

if either the first access point or the second access point is a master of the other of the first or the second access point, wherein the other of the first access point or the second access point is a slave of the master access point, adjusting the beacon timing of the slave access point to the beacon timing of the master access point; and

if neither the first access point or the second access point is a master of the other of the first access point or the second access point, determining a common master access point and adjusting the beacon timing of the first access point and the beacon timing of the second access points to a beacon timing of the common master access point.

16. A method for associating a computing device with a new access point group in a WLAN whenever the computing device crosses an access point boundary, wherein the new access point group comprises a plurality of access points, comprising:

discovering when the computing device has crossed an access point boundary;

the computing device sending a request to the new access point group; and

assigning an association identification number to the computing device.

17. A method for associating a computing device with a new access point group in a WLAN whenever the computing device crosses an access point boundary as claimed in claim 16, wherein discovering when the computing device has crossed an access point boundary comprises, the computing device:

detecting a group identification in the beacon broadcast of one of the plurality of access points in the new access point group; and

determining that the beacon broadcast of one of the plurality of access points in the new access point group is stronger than a beacon broadcast of one of a plurality of access points in an old access point group.

18. A method for associating a computing device with a new access point group in a WLAN whenever the computing device crosses an access point boundary as claimed in claim 16, wherein the computing device sending a request to the new access point group, comprises:

the computing device sending the request to one of the plurality of access points in the access point group; and

if the one of the plurality of access points in the access point group is not a root access point, communicating the request to the root access point.

19. A method for associating a computing device with a new access point group in a WLAN whenever the computing device crosses an access point boundary as claimed in claim 16, wherein assigning an association identification number to the computing device is performed by a root access point.

20. A method for associating a computing device with a new access point group in a WLAN whenever the computing device crosses an access point boundary, wherein the new access point group comprises a plurality of access points, comprising:

discovering when the computing device has crossed an access point boundary, comprising the computing device detecting a group identification in the beacon broadcast of one of the plurality of access points in the new access point group and determining the beacon broadcasts of the one of the plurality of access points in the new access point group is stronger than a beacon broadcast of one of a plurality of access points in an old access point group;

the computing device sending a request to the new access point group, comprising;

the computing device sending the request to one of the plurality of access points in the access point group; and

if the one of the plurality of access points in the access point group is not a root access point, communicating the request to a root access point; and

assigning an association identification to the computing device, wherein assigning an association identification to the computing device is performed by the root access point.

21-37. -37. (canceled)

38. A WLAN, comprising:

a means for establishing paging areas;

a means for communicating access group information to a computing device; and

a means for locating a computing device within the WLAN.

39. A method for implementing dormant mode with paging in a WLAN, comprising:

establishing paging areas;

communicating access group information to a computing device; and

locating a computing device.

40-45. -45. (canceled)

46. A method comprising:

receiving a beacon timing difference between a beacon timing of the first access point and a beacon timing of the second access point to ascertain a beacon timing difference; and

adjusting beacon timing to make the beacon timing of the first access point be equal to the beacon timing of the second access point.

47. The method defined in claim 46 further comprising a computing device calculating the difference between beacon timings of the first and second access points.

48. The method defined in claim 47 wherein the computing device calculating the difference between beacon timings comprises:

periodically shifting into an active communication mode to detect a first access point beacon at a first predetermined time for a first time interval while the computing device is within range of the first access point;

periodically shifting into an active communication mode to detect a second access point beacon at a second predetermined time for a second time interval while the computing device is within range of the second access point; and

subtracting the one of the at least one predetermined times from the time interval to calculate the beacon timing difference.

49. The method defined in claim 46 further comprising:

identifying the first access point; and

communicating the beacon timing difference to the first access point.

50-55. -55. (canceled)