Timing synchronization and beacon generation for mesh points operating in a wireless mesh network

• US 7,706,822 B2
• Filed: 07/26/2006
• Issued: 04/27/2010
• Est. Priority Date: 08/24/2005
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Gossian, Hrishikesh, Emeott, Stephen P.
• Primary Examiner(s): Nguyen, Duc
• Assistant Examiner(s): Nguyen, Hai V
• Application Number:
  US11/460,017
• Publication Number:
  US 20070050523A1
• Time in Patent Office: 1,371 Days
• Field of Search: 455/502
• US Class Current: 455/502
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method is used by a mesh point that includes one or more step of receiving one of a beacon and probe response from an other mesh point; setting a state of whether the mesh point is already synchronized with one or more peers to true and performing a beacon timing synchronization function when the mesh point is in the unsynchronized state and the other mesh point requests synchronization from a peer mesh point; adding an identity of the other mesh point to a database of beacon senders maintained by the mesh point and performing a beacon timing synchronization function when the mesh point and the other mesh point are both synchronized; and providing indications of whether the mesh point supports synchronization, requests synchronization from a peer mesh point, and is already synchronized with one or more peer.

Claims

1. A method used by a mesh point, comprising:

formatting a synchronization capability field of one of a beacon and probe response that includes;

an indication of whether the mesh point supports synchronization (SynchSupp), an indication of whether the mesh point requests synchronization from a peer mesh point (SynchReq);

an indication of whether the mesh point is already synchronized with one or more peers (SynchPeers); and

when the mesh point is one of a non-access point mesh point and a lightweight access point;

initiating a beacon backoff function upon the expiration of a target beacon transmission timer when at least one of SynchReq and SynchPeers of the mesh point are true; and

cancelling the beacon backoff function when one of a beacon and probe response from an other mesh point is received in which at last one of SynchReq and SynchPeers of the other mesh point are true.

2. The method according to claim 1, wherein the mesh point is one of an access point, a non-access point, and a lightweight mesh point.

3. The method according to claim 1, wherein the initiating of the beacon backoff function comprises initiating a random backoff function.

4. The method according to claim 1, further comprising:

transmitting a beacon upon the expiration of the target beacon transmission time when both of SynchReq and SynchPeers of the mesh point are false.

5. The method according to claim 1, wherein the canceling of the beacon backoff function is not performed when the mesh point is not associated with the other mesh point.

6. The method according to claim 1, further comprising transmitting a beacon when a random backoff timer of the beacon transmission function expires.

7. A method used by mesh point that is one of a non-access point mesh point and a lightweight mesh point, comprising:

receiving one of a beacon and probe response from an other mesh point;

determining whether the mesh point is in an unsynchronized state;

wherein the mesh point is in an unsynchronized state when both SynchReq and SynchPeers of the mesh point are false;

determining from an indicator in the one of the beacon and probe response whether the other mesh point requests synchronization from a peer mesh point (SynchReq);

setting a state of whether the mesh point is already synchronized with one or more peers (SynchPeers) to true and performing a beacon timing synchronization function when the unsynchronized state of the mesh point and the SynchReq of the other mesh point are both true.

8. The method according to claim 7, wherein neither the setting the state of SynchPeers to true nor performing the beacon timing synchronization function are performed when the mesh point is not associated with the other mesh point.

9. The method according to claim 7, wherein the setting of the state further comprises adding an identity of the other mesh point to a database of mesh points that are beacon senders maintained by the non-access point mesh point.

10. A method used by a mesh point that is one of a non-access point mesh point and a lightweight mesh point, comprising:

receiving one of a beacon and probe response from an other mesh point;

determining that the mesh point is in a synchronized state;

determining from one or more indicators in the one of the beacon and probe response whether the other mesh point is synchronized;

wherein the one or more indicators in the one of the beacon and probe response comprise an indication of whether the other mesh point requests synchronization from a peer mesh point (SynchReq), and

an indication of whether the other mesh point is already synchronized with one or more peers (SynchPeers), and the other mesh point is synchronized when at least one of SynchReq and SynchPeers of the other mesh point is true;

adding an identity of the other mesh point to a database of beacon senders maintained by the mesh point and performing a beacon timing synchronization function when the mesh point and the other mesh point are both synchronized.

11. The method according to claim 10, wherein the adding of the identity of the other mesh point and the performing of the beacon timing function are further dependent upon the mesh point and the other mesh point being associated.

12. The method according to claim 10, further comprising:

determining whether the other mesh point is an access point, and

storing the difference between a timing synchronization function of the other mesh point and a timing synchronization function of the mesh point as a beacon offset value and storing the delivery traffic indication map and beacon intervals when the other access point is an access point mesh point and the other mesh point is not in a synchronized state.

13. The method according to claim 10, further comprising:

determining whether the other mesh point is an access point mesh point, and deleting an identity of the other mesh point from a database of beacon senders maintained by the mesh point when the other mesh point is a non-access point mesh point and the other mesh point is not in a synchronized state.