# US 2014/0192785 A1 · Mitigating overlapping basic service set interference in smart grid networks

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- Number: US 2014/0192785 A1
- Document ID: US20140192785A1
- Status: Published application
- Kind: A1
- Application number: 13/993,082
- Filed: 2011-09-30
- Published: 2014-07-10
- Earliest claimed: 2011-09-30
- Assignees: Intel Corporation
- Inventors: Michelle X. Gong
- Web page: https://patentgrep.com/patent/US20140192785A1

## CPC

- H04W 56/001: {Synchronization between nodes}
- H04W 92/20: between access points
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Systems and methods for implementing a mitigation of overlapping basic service set (OBSS) interference are disclosed. Synchronization of access point (AP) devices may be based upon a transmission synchronization function (TSF) offset between the AP devices. In an implementation, collaboration between the AP devices may include exchanging of beacon schedule frames through a controller, or over the air media access.

## Claims

### Claim 1

A method for mitigating Overlapping Basic Service Set (OBSS) interference in a wireless communications network, the method comprising:
storing a timing synchronization function (TSF) offset that includes a timing offset between access point (AP) devices;
determining a target beacon transmission time (TBTT) of the AP devices;
synchronizing the AP devices based on the TBTT;
collaborating to allocate different beacon intervals, by exchanging beacon frames that contain beacon schedule frames;
choosing beacon interval allocations; and
transmitting the chosen allocated beacon interval allocations.

### Claim 2 (depends on 1)

The method of claim 1, wherein the synchronizing the AP devices based on the TWIT requires no external clock to control the AP devices.

### Claim 3 (depends on 1)

The method of claim 1, wherein the collaborating is controlled by a controller, which is a router device that connects the AP devices.

### Claim 4 (depends on 1)

The method of claim 1, wherein the beacon schedule frames includes a start TBTT field , which is set to zero to reduce overhead in the beacon schedule frame.

### Claim 5 (depends on 1)

The method of claim 1, wherein the beacon interval allocations chosen by the AP devices are not overlapping in order to mitigate overlapping basic service set (OBSS) interference.

### Claim 6

A wireless communications network comprising:
an access point device synchronized with other access point devices, wherein the access point device collaborates by exchanging beacon frames with the other access point devices to allocate different beacon intervals, wherein the allocated beacon intervals are chosen by the synchronized access point device and the other access point device to avoid overlapping beacon intervals; and
a station, associated with the access point device, wherein the station adopts the beacon interval allocation chosen by the access point device.

### Claim 7 (depends on 6)

The wireless communications network of claim 6, wherein the access point device and the other access point devices are synchronized by determining target beacon transmission time (IBTI) of the access point device and the other access point device.

### Claim 8 (depends on 6)

The wireless communications network of claim 6, wherein the access point is synchronized without requiring an external clock to control the synchronization.

### Claim 9 (depends on 6)

The wireless communications network of claim 6, wherein the beacon frame includes a beacon schedule frame that contains a duration that indicates a contiguous period of time of the beacon interval in the access point device.

### Claim 10 (depends on 6)

The wireless communications network of claim 6, wherein the beacon frame includes a beacon schedule frame that contains beacon interval periodicity that identifies a number of beacon intervals contained in a super beacon interval, wherein the super beacon interval includes one or more beacon intervals.

### Claim 11 (depends on 6)

The wireless communications network of claim 6, wherein the beacon frame includes a beacon schedule frame that contains a start TBTT.

### Claim 12 (depends on 11)

The wireless communications network of claim 11, wherein the start TBTT is set to zero to reduce overhead in the beacon schedule frame.

### Claim 13 (depends on 6)

The wireless communications network of claim 6, which further includes a controller, wherein the controller controls the collaboration between the access point device and the other access point device.

### Claim 14

An access point (AP) device comprising:
one or more processors that generate beacon frames for collaborating different beacon intervals between the AP device with other AP device, wherein the beacon intervals are allocated at the AP device and the other AP devices to avoid overlapping beacon intervals;
memory configured to the one or more processors that identify a target beacon transmission time (TBTT) of the AP device and other AP device for synchronization; and
a transmitter to wirelessly transmit the beacon frames.

### Claim 15 (depends on 14)

The AP device of claim 14, wherein the synchronization of the AP device and the other AP device requires no external clock or controller.

### Claim 16 (depends on 14)

The AP device of claim 14, wherein the beacon frame includes a beacon schedule frame that contains a bitmap field identifying which beacon interval within a super beacon interval is being used by the AP device.

### Claim 17 (depends on 14)

The AP device of claim 14, wherein the beacon frame includes a beacon schedule frame that contains a beacon interval periodicity that defines number of beacon intervals contained in a super beacon interval of the AP device, wherein the super beacon interval includes one or more beacon intervals.

### Claim 18 (depends on 14)

The AP device of claim 14, wherein the beacon interval allocations are chosen by the AP device to mitigate Overlapping Basic Service Set (OBSS) interference;

### Claim 19 (depends on 14)

The AP device of claim 14, wherein the beacon frame includes a beacon schedule frame that contains a start TBTT to identify starting points in a super beacon interval, wherein the super beacon interval includes one or more beacon intervals in the AP device.

### Claim 20 (depends on 14)

The AP device of claim 14, wherein the start TBTT is set to zero to reduce overhead in the beacon schedule frame.

### Claim 21

A computer-readable medium having stored thereon a data structure, comprising:
a frame header data field that includes a media access control address (MAC address) to identify access point source and access point destination of a beacon schedule frame;
a start transmission beacon transmission time (start TBTT) data field that defines beginning of a super beacon interval in the access point source, wherein the super beacon interval includes of more than one beacon interval;
a beacon interval periodicity data field that defines number of beacon intervals that are included in the super beacon interval; and
a bitmap data field that defines which beacon interval in the super beacon interval is being used by the access point source.

### Claim 22 (depends on 21)

The computer-readable medium of claim 21, wherein the beacon schedule frame is used for collaboration between the access point source and the access point destination to allocate different beacon intervals.

### Claim 23 (depends on 21)

The computer-readable medium of claim 21, wherein the start TBTT is set to zero to reduce overhead in the beacon schedule frame

### Claim 24 (depends on 21)

The computer-readable medium of claim 21 further comprising a duration data field that identifies a contiguous period of time of the beacon interval that the access point source is using.

### Claim 25 (depends on 21)

The computer-readable medium of claim 21 further comprising a beacon schedule information element (IE) data field that identifies the beacon intervals that are being used by the access point source.

### Claim 26 (depends on 21)

The computer-readable medium of claim 21 further comprising a length data field that identifies a period for the beacon interval that is used by the access point source.