System and method for communicating beacon transmissions in wireless local area network (WLAN) systems

• US 7,515,577 B2
• Filed: 06/29/2006
• Issued: 04/07/2009
• Est. Priority Date: 06/29/2006
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Pandey, Aparna, Ekl, Randy L., Ware, Christopher G.
• Primary Examiner(s): D'Agosta; Stephen M
• Application Number:
  US11/427,509
• Publication Number:
  US 20080002632A1
• Time in Patent Office: 1,013 Days
• Field of Search: 370/324, 370/331, 370/338, 370/328, 370/350, 455/41.2, 455/41.3, 455/432.1, 455/435.1, 455/435.2
• US Class Current: 370/338
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 48/12 using downlink control channel

Abstract

A method for communicating beacon transmissions from a wireless access point (WAP) to a client transceiver in a wireless local area network (WLAN) system (500) includes obtaining a reference timing for the wireless access point (WAP) (502). The sector configuration and the sector timing in the WAP is then determined (503). A virtual target beacon transmission time (TBTT) for the sector of interest serviced by the WAP is then calculated (506), as is a channel number of the sector of interest. Finally, the method provides for listening (507) for a sector beacon signal from the sector of interest at the virtual TBTT and the calculated channel number.

Claims

1. A method for communicating beacon transmissions from a wireless access point (WAP) with a plurality of sectors by a client transceiver in a wireless local area network (WLAN) system comprising the steps of:

obtaining a reference timing for the WAP;

determining a sector configuration of the WAP;

determining a sector beacon timing of the WAP;

determining if the client is in a time period for sector discovery;

calculating a virtual target beacon transmission time (TBTT) for a sector of interest; and

listening for the WAP sector beacon at the calculated virtual TBTT for the sector of interest.

2. A method for communicating beacon transmissions as in claim 1, further comprising the step of:

receiving the sector beacon signal from the sector of interest.

3. A method for communicating beacon transmissions as in claim 1, wherein the step of calculating further comprises the step of:

determining a channel number for a sector of interest.

4. A method for communicating beacon transmissions as in claim 3, wherein the step of listening further comprises the step of:

listening for the WAP sector beacon at the determined channel number for the sector of interest.

5. A method for communicating beacon transmissions as in claim 1, further comprising the step of:

synchronizing the client transceiver based on the calculated virtual TBTT.

6. A method for communicating beacon transmissions as in claim 1, wherein the WAP utilizes at least one directional antenna.

7. A method for communicating beacon transmissions as in claim 1, wherein the WAP is at least one of a serving Access Point for the client receiver or a neighboring Access Point for the client receiver.

8. A method for communicating beacon transmissions as in claim 1, wherein the reference timing is at least one of the virtual TBTT or a virtual timing synchronization function (TSF) timer associated with at least one sector of the WAP.

9. A method for communicating beacon transmissions as in claim 1, wherein the sector configuration of the WAP includes at least one of the number of channels, the number of sectors and the number of sectors in each channel used at the WAP.

10. A method for communicating beacon transmissions as in claim 1, wherein the sector beacon timing may include at least one of the virtual timing synchronization function (TSF) timer value for a sector, inter-channel offset and beacon interval.

11. A method for communicating beacon transmissions as in claim 10, wherein the framing information includes at least one of a data frame, a trigger frame and a dummy frame.

12. A method for communicating a sector of operation to a client transceiver in a wireless local area network (WLAN) system comprising the steps of:

receiving at least one announcement from a wireless access point (WAP);

determining a sector configuration of the WAP from that at least one announcement;

determining the sector beacon timing from within the at least one announcement;

determining a channel number for a sector of interest serviced by the WAP;

calculating a virtual target beacon transmission time (TBTT) for the sector of interest serviced by the WAP; and

listening for a sector beacon signal from the sector of interest at the virtual target beacon transmission time (TBTT) and the determined channel number.

13. A method for communicating a sector of operation to a client transceiver as in claim 12, further comprising the step of:

receiving the sector beacon signal from the sector of interest.

14. A method for communicating a sector of operation to a client transceiver as in claim 12, wherein the WAP uses at least one directional antenna.

15. A method for communicating a sector of operation to a client transceiver as in claim 12, including the step of:

synchronizing the client transceiver to the WAP based on the calculated virtual target beacon transmission time (TBTT) for the sector of interest.

16. A method for communicating a sector of operation to a client transceiver as in claim 14, wherein synchronization is performed using a virtual timing synchronization function (TSF) timer.

17. A method for communicating a sector of operation to a client transceiver as in claim 12, wherein the sector configuration of the WAP includes at least one of the number of channels, the number of sectors and the number of sectors in each channel used at the WAP.

18. A method for communicating a sector of operation to a client transceiver as in claim 12, wherein the sector beacon timing may include at least one of the virtual timing synchronization function (TSF) timer value for a sector, inter-channel offset and beacon interval.