Method and apparatus for dormant mode support with paging

• US 7,689,225 B2
• Filed: 10/04/2002
• Issued: 03/30/2010
• Est. Priority Date: 01/28/2002
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Ly; Nghi H
• Application Number:
  US10/264,807
• Publication Number:
  US 20030145092A1
• Time in Patent Office: 2,734 Days
• Field of Search: 455/450, 455/451, 455/452.1, 455/464, 455/509, 455/547, 455/343.1, 370/329, 370/341, 370/431
• US Class Current: 455/450
• 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 of communicating access point group information to a computing device in a wireless local area network (WLAN), comprising:

each of at least two access point groups broadcasting beacons on an assigned channel over the WLAN for that access point group within a paging area defined by that access point group, wherein the beacons broadcast by each access point group include a common paging area identifier unique to that access point group, and further wherein at least one access point group includes at least a first access point and a second access point;

periodically awakening the computing device to detect the beacons of the first access point and the second access point; and

aligning a first beacon timing of the first access point with a second beacon timing of the second access point to cause the first beacon timing and the second beacon timing to be received by the computing device at substantially a same time.

2. A wireless local area network (WLAN) communication system, comprising:

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

the first access point and the second access point to broadcast, in the paging area for the at least one group, beacons that include a common paging area identifier unique to the at least one group, wherein a first beacon timing of the first access point is adjusted to align with a second beacon timing of the second access point to cause the first beacon timing and the second beacon timing to be received by a computing device using the WLAN at substantially a same time.

3. The communication system as claimed in claim 2, wherein the unique paging area identifier comprises a unique paging area identification number.

4. The communication system as claimed in claim 3, 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.

5. The communication system as claimed in claim 2, wherein one access point in the at least one group of access points having at least two access points is a master and one or more other access points in the at least one group of access points are slaves, and each access point that is a slave is coupled to exactly one access point that is the master.

6. The communication system as claimed in claim 5, wherein access points communicate using IEEE Inter Access Point Protocol.

7. The communication system as claimed in claim 6, wherein the IEEE Inter Access Point Protocol comprises a join operation, a leave operation, a group merge operation, a group prune operation and a group devolution operation.

8. The communication system as claimed in claim 2 further comprising a single channel for paging and IP traffic.

9. The communication system as claimed in claim 2 further comprising a channel for paging and a channel for IP traffic.

10. The communication system as claimed in claim 2 further comprising a channel for IP traffic and a common dedicated channel for paging for each of the plurality of access point groups.

11. The communication system as claimed in claim 10, wherein each of the plurality of access point groups has a root access point that assigns the common dedicated channel for paging.

12. The communication system as claimed in claim 2 further comprising a computing device.

13. The communication system as claimed in claim 12, wherein each of the plurality of access points broadcasts a beacon, wherein the beacon includes a beacon timing for that access point, and further wherein a difference between the beacon timing for a first access point and the beacon timing for a second access point define a beacon timing difference;

and

wherein the computing device and at least a subset of the plurality of access points use the beacon timing difference to synchronize the beacon timings of the plurality of access points.

14. The communication system defined in claim 2 further comprising a mobile unit operable in a power savings mode, wherein at least one access point uses paging when the mobile unit is in the power savings mode and is in the paging area associated with the at least one access point to notify the mobile unit that a message has been received for the mobile unit.

15. The communication system defined in claim 14 wherein the at least one mobile unit buffers the message until the mobile unit exits the power savings mode and receives the message.

16. The communication system defined in claim 2 wherein at least one of the first access point or the second access point sends a beacon on a dedicated channel, the beacon containing the common paging area identifier identifying the group of access points to which the at least one access point belongs.

17. The method of claim 2, the first access point serves as a slave access point and the second access point serves as a master access point.