Distributed seamless roaming in wireless networks

• US 9,008,126 B2
• Filed: 07/16/2014
• Issued: 04/14/2015
• Est. Priority Date: 10/19/2012
• Status: Active Grant

• Current Assignee: Ubiquiti Inc.
• Original Assignee: Ubiquiti Networks, Inc. (Ubiquiti Inc.)
• Inventors: Dayanandan, Sriram, Yang, Bo-chieh, Lee, Yuan-Hsiang, Luoh, Keh-Ming, Pera, Robert J.
• Primary Examiner(s): Pezzlo, John
• Application Number:
  US14/333,309
• Publication Number:
  US 20140329522A1
• Time in Patent Office: 272 Days
• Field of Search: 370/252, 370/329, 370/503
• US Class Current: 370/503
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04W 36/0044 of quality context information
• CPC Class Codes: H04W 36/0094 Definition of hand-off measurement parameters
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• 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
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

One embodiment of the present invention provides a system for configuring an access point in a wireless network. During operation, the access point discovers one or more existing access points associated with the wireless network. The access point then obtains a set of configuration information from one existing access point, and synchronizes a local timestamp counter to a selected existing access point, thereby allowing the access point to be configured without using a centralized management station.

Claims

1. A method for facilitating communication in a wireless network, comprising:

obtaining, by a local access point that has not yet joined a wireless network, a set of configuration information from an existing access point that belongs to the wireless network;

synchronizing a local timing mechanism of the local access point to a selected existing access point of the wireless network without using a centralized management station that configures the local access point to join the wireless network; and

allowing a user station to be associated with the local access point subsequent to determining that the local access point has the best signal strength of the user station.

2. The method of claim 1, wherein the set of configuration information comprises:

an association ID (AID) usage indication which indicates one or more AIDs currently in use in the wireless network; and

an encryption key.

3. The method of claim 1, wherein synchronizing the local timing mechanism to the selected existing access point comprises receiving information on timestamp hierarchy for the existing access point.

4. The method of claim 1, further comprising broadcasting signal-strength indication associated with the user station;

and

receiving signal-strength indication associated with the user station from other access points in the wireless network.

5. The method of claim 1, wherein synchronizing the local timing mechanism to the selected existing access point comprises selecting the existing access point based on timestamp hierarchy associated with one or more existing access points.

6. The method of claim 1, further comprising determining that the signal strength associated with the user station is below a predetermined threshold;

querying other access points for their signal strength associated with the same user station; and

in response to there being at least one other access point receiving a sufficiently strong signal from the user station, handing over the user station to the access point with the strongest signal strength.

7. The method of claim 1, further comprising handing over the user station to another access point;

and

performing maintenance on the local access point without disruption to service for the user station.

8. A wireless communication system for facilitating communication in a wireless network, comprising:

a configuration module adapted to obtain, by a local access point that has not yet joined a wireless network, a set of configuration information from an existing access point that belongs to the wireless network;

a synchronization module adapted to synchronize a local timing mechanism of the local access point to a selected existing access point of the wireless network without using a centralized management station that configures the local access point to join the wireless network; and

a user-station association module adapted to allow a user station to be associated with the local access point subsequent to determining that the local access point has the best signal strength of the user station.

9. The wireless communication system of claim 8, wherein the set of configuration information comprises:

an association ID (AID) usage indication which indicates one or more AIDs currently in use in the wireless network; and

an encryption key.

10. The wireless communication system of claim 8, wherein while synchronizing the local timing mechanism to the selected existing access point, the synchronization module is adapted to receive information on timestamp hierarchy for the existing access point.

11. The wireless communication system of claim 8, wherein the user-station association module is further adapted to broadcast signal-strength indication associated with the user station;

and

receive signal-strength indication associated with the user station from other access points in the wireless network.

12. The wireless communication system of claim 8, wherein while synchronizing the local timing mechanism to the selected existing access point, the synchronization module is further adapted to select the existing access point based on timestamp hierarchy associated with one or more existing access points.

13. The wireless communication system of claim 8, wherein the user-station association module is further adapted to:

determine that the signal strength associated with the user station is below a predetermined threshold;

query other access points for their signal strength associated with the same user station; and

in response to there being at least one other access point receiving a sufficiently strong signal from the user station, hand over the user station to the access point with the strongest signal strength.

14. The wireless communication system of claim 8, wherein the user-station association module is further adapted to hand over the user station to another access point;

and

wherein the wireless communication system further comprises a maintenance module adapted to perform maintenance on the local access point without disruption to service for the user station.

15. A computing system, comprising:

a processor; and

a storage device storing instructions which when executed by the processor cause the processor to perform a method, the method comprising;

obtaining, by a local access point that has not yet joined a wireless network, a set of configuration information from an existing access point that belongs to the wireless network;

synchronizing a local timing mechanism of the local access point to a selected existing access point of the wireless network without using a centralized management station that configures the local access point to join the wireless network; and

allowing a user station to be associated with the local access point subsequent to determining that the local access point has the best signal strength of the user station.

16. The computing system of claim 15, wherein the set of configuration information comprises:

an association ID (AID) usage indication which indicates one or more AIDs currently in use in the wireless network; and

an encryption key.

17. The computing system of claim 15, wherein synchronizing the local timing mechanism to the selected existing access point comprises receiving information on timestamp hierarchy for the existing access point.

18. The computing system of claim 15, wherein the method further comprises broadcasting signal-strength indication associated with the user station;

and

receiving signal-strength indication associated with the user station from other access points in the wireless network.

19. The computing system of claim 15, wherein synchronizing the local timing mechanism to the selected existing access point comprises selecting the existing access point based on timestamp hierarchy associated with one or more existing access points.

20. The computing system of claim 15, further comprising determining that the signal strength associated with the user station is below a predetermined threshold;

querying other access points for their signal strength associated with the same user station; and

in response to there being at least one other access point receiving a sufficiently strong signal from the user station, handing over the user station to the access point with the strongest signal strength.

21. The computing system of claim 15, further comprising handing over the user station to another access point;

and

performing maintenance on the local access point without disruption to service for the user station.