WIRELESS CONNECTIVITY FOR SENSORS

• US 20100308956A1
• Filed: 06/03/2009
• Published: 12/09/2010
• Est. Priority Date: 06/03/2009
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Sensormatic Electronics Corporation (Johnson Controls International plc)
• Inventors: ALICOT, Jorge F., RELIHAN, Timothy J.
• Granted Patent: US 8,274,359 B2
• Time in Patent Office: Days
• US Class Current: 340/3.1
• CPC Class Codes: G08B 13/2402 Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting mechanical aspects of the tags, e.g. related to locking E05B73/0017; RFID readers G06K7/00; RFID tags G06K19/00; access control systems G07C9/00; anti-theft control in point of sale systems G07G3/003; security seals G09F3/03

Abstract

A wireless access point communicates messages in an electronic article surveillance (EAS) network. The EAS network includes at least one EAS sensor hard-wired to at least one wireless device node. The wireless access point includes a wired communication interface, a wireless communication interface and a controller. The controller is electrically coupled to the wired communication interface and to the wireless communication interface. The wired communication interface operates to receive a message. The message includes a sub-layer address corresponding to an EAS sensor. The wireless communication interface operates to broadcast the message and to receive an acknowledgement of the broadcast message. The acknowledgment originates from the EAS sensor corresponding to the sub-layer address. The controller operates to transfer the message between the wired communication interface and the wireless communication interface.

Claims

1. A wireless access point for communicating messages in an electronic article surveillance network, the electronic article surveillance network including at least one electronic article surveillance sensor hard-wired to at least one wireless device node, the wireless access point comprising:

a wired communication interface operable to receive a message, the message including a sub-layer address corresponding to an electronic article surveillance sensor;

a wireless communication interface operable to;

broadcast the message; and

receive an acknowledgement of the broadcast message, the acknowledgment originating from the electronic article surveillance sensor corresponding to the sub-layer address; and

a controller electrically coupled to the wired communication interface and to the wireless communication interface, the controller operable to transfer the message between the wired communication interface and the wireless communication interface.

2. The wireless access point of claim 1, wherein responsive to not receiving the acknowledgement of the broadcast message within a predetermined time, the wireless communication interface is further operable to rebroadcast the message.

3. The wireless access point of claim 1, wherein the wired communication interface receives the message from a local device manager.

4. The wireless access point of claim 1, further comprising:

a universal asynchronous receiver/transmitter buffer for receiving the message through the first wired communication interface, the message having been received as a series of data packets;

a radio frequency data transfer buffer for storing data packets to be broadcast through the first wireless communication interface; and

a serial data transfer buffer operable to transfer data packets between the universal asynchronous receiver/transmitter buffer and the radio frequency data transfer buffer; and

wherein the wired communication interface is further operable to receive a data packet on the universal asynchronous receiver/transmitter buffer while the controller simultaneously transfers data packets from the serial data transfer buffer to the radio frequency data transfer buffer.

5. The wireless access point of claim 4, wherein the controller transfers data packets from the universal asynchronous receiver/transmitter buffer to the serial data transfer buffer in bursts, the bursts of data packets having a variable time lapse between bursts, the access point further comprises:

a predictor operable to;

measure a serial idle time between bursts;

calculate a moving average of the measured serial idle time between bursts;

adaptively predict a serial idle trigger based on the moving average of the measured serial idle time between bursts; and

responsive to the serial idle time between bursts reaching the serial idle trigger, transfer data packets from the serial data transfer buffer to the radio frequency data transfer buffer.

6. The wireless access point of claim 5, wherein the serial idle trigger is a weighted sum of a long term predictor value and the moving average of the measured serial idle time between bursts plus a minimum serial idle constant.

7. The wireless access point of claim 1, wherein the wireless communication interface is further operable to:

transmit a point-to-point message to a wireless node device, the point-to-point message including the wireless network layer address corresponding to the wireless device node; and

receive an acknowledgement to the point-to-point message from the wireless device node corresponding to the wireless network layer address.

8. An electronic article surveillance network supporting at least one electronic article surveillance sensor having a corresponding sub-layer address, the electronic article surveillance network comprising:

an access point operable to;

receive a message through a first wired communication interface, the message including a sub-layer address corresponding to an electronic article surveillance sensor;

broadcast the message through a first wireless communication interface; and

receive an acknowledgement of the broadcast message through the first wireless communication interface; and

at least one wireless device node having a wireless network layer address, the at least one wireless device node wirelessly coupled to the access point and hard-wired to the at least electronic article surveillance sensor, the at least one wireless device node operable to;

receive the broadcast message through a second wireless communication interface;

forward the broadcast message through a second wired communication interface to an electronic article surveillance sensor corresponding to the sub-layer address included in the received broadcast message;

receive an acknowledgement of the broadcast message through the second wired communication interface from the electronic article surveillance sensor corresponding to a sub-layer address; and

forward the acknowledgement of the broadcast message through the second wireless communication interface.

9. The network of claim 8, wherein responsive to not receiving the acknowledgement of the broadcast message within a predetermined time, the access point is further operable to rebroadcast the message.

10. The network of claim 8, further comprising a local device manager electrically connected to the access point through the first wired communication interface, the local device manager being operable to transmit the message to the access point.

11. The network of claim 8, wherein the access point further includes:

a universal asynchronous receiver/transmitter buffer for receiving the message through the first wired communication interface, the message having been received as a series of data packets;

a radio frequency data transfer buffer for storing data packets to be broadcast through the first wireless communication interface; and

a serial data transfer buffer operable to transfer data packets between the universal asynchronous receiver/transmitter buffer and the radio frequency data transfer buffer; and

wherein the access point is further operable to receive a data packet on the universal asynchronous receiver/transmitter buffer while simultaneously transferring data packets from the serial data transfer buffer to the radio frequency data transfer buffer.

12. The network of claim 11, wherein the access point transfers data packets from the universal asynchronous receiver/transmitter buffer to the serial data transfer buffer in bursts, the bursts of data packets having a variable time lapse between bursts, the access point is further operable to:

measure a serial idle time between bursts;

calculate a moving average of the measured serial idle time between bursts;

adaptively predict a serial idle trigger based on the moving average of the measured serial idle time between bursts; and

responsive to the serial idle time between bursts reaching the serial idle trigger, transfer data packets from the serial data transfer buffer to the radio frequency data transfer buffer.

13. The network of claim 12, wherein the serial idle trigger is a weighted sum of a long term predictor value and the moving average of the measured serial idle time between bursts plus a minimum serial idle constant.

14. The network of claim 8, wherein the access point is further operable to:

transmit a point-to-point message to a wireless node device through the first wireless communication interface, the point-to-point message including the wireless network layer address corresponding to the wireless device node; and

receive an acknowledgement to the point-to-point message from the wireless device node corresponding to the wireless network layer address through the first wireless communication interface.

15. A method for communicating messages in an electronic article surveillance network, the electronic article surveillance network including at least one electronic article surveillance sensor hard-wired to at least one wireless device node, the method comprising:

receiving a message through a wired communication interface, the message including a sub-layer address corresponding to an electronic article surveillance sensor;

broadcasting the message through a wireless communication interface; and

receiving an acknowledgement of the broadcast message through the wireless communication interface, the acknowledgment originating from the electronic article surveillance sensor corresponding to the sub-layer address.

16. The method of claim 15, wherein responsive to not receiving the acknowledgement of the broadcast message within a predetermined time, rebroadcasting the message.

17. The method of claim 15, further comprising:

receiving the message through a universal asynchronous receiver/transmitter buffer, the message having been received as a series of data packets;

using a serial data transfer buffer operable to transfer data packets between the universal asynchronous receiver/transmitter buffer and the radio frequency data transfer buffer;

storing data packets to be broadcast through the first wireless communication interface in a radio frequency data transfer buffer; and

simultaneously receiving a data packet on the universal asynchronous receiver/transmitter buffer while the controller transfers data packets from the serial data transfer buffer to the radio frequency data transfer buffer.

18. The method of claim 17, wherein the data packets are transferred from the universal asynchronous receiver/transmitter buffer to the serial data transfer buffer in bursts, the bursts of data packets having a variable time lapse between bursts, the method further comprises:

measuring a serial idle time between bursts;

calculating a moving average of the measured serial idle time between bursts;

adaptively predicting a serial idle trigger based on the moving average of the measured serial idle time between bursts; and

responsive to the serial idle time between bursts reaching the serial idle trigger, transferring data packets from the serial data transfer buffer to the radio frequency data transfer buffer.

19. The method of claim 18, wherein the serial idle trigger is a weighted sum of a long term predictor value and the moving average of the measured serial idle time between bursts plus a minimum serial idle constant.

20. The method of claim 15, further comprising:

transmitting a point-to-point message to a wireless node device, the point-to-point message including the wireless network layer address corresponding to the wireless device node; and

receiving an acknowledgement to the point-to-point message from the wireless device node corresponding to the wireless network layer address.