SYSTEM AND METHOD FOR OPERATING A SYNCHRONIZED WIRELESS NETWORK

• US 20120092130A1
• Filed: 05/17/2007
• Published: 04/19/2012
• Est. Priority Date: 08/26/2004
• Status: Active Grant

• Current Assignee: Avante International Technology
• Original Assignee: Panasec Corporation
• Inventors: Chung, Kevin Kwong-Tai, Li, Jing Jian
• Granted Patent: US 8,174,383 B1
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: B60R 2325/105 Radio frequency identification data [RFID]
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: G07G 1/009 the reader being an RFID reader
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00

Abstract

A system and method for operating a wireless network comprising a plurality of devices each having a powered down mode, a receive/transmit mode, and a timer, may include a master device and a defined time interval. Time interval information and synchronizing information are communicated to the plurality of devices of the wireless network, whereby the timers of each of the plurality of devices are set to time substantially the same time interval, and the time intervals of the plurality of devices of the wireless network are substantially synchronized.

Claims

1. A wireless network comprising:

a plurality of RFID devices each having a powered down mode and a receive/transmit mode in which messages can be received and/or transmitted, and each including a timer operable in the powered down mode for enabling the receive/transmit mode periodically in response to time interval information;

a plurality of relay devices each having a powered down mode and a receive/transmit mode in which messages may be received and/or transmitted, and each including a timer operable in the powered down mode for enabling the receive/transmit mode periodically in response to time interval information;

wherein one of said RFID devices or one of said relay devices is designated as a master device and wherein said plurality of RFID devices and said plurality of relay devices are operable to establish a wireless communication network;

wherein said master device defines time interval information and communicates the time interval information at least to said plurality of relay devices, whereby the timers of each of said plurality of relay devices are set to time substantially the same time interval; and

wherein said master device communicates at least to said plurality of relay devices synchronization information to start the respective timers of said plurality of relay devices substantially simultaneously,

whereby the time intervals of said plurality of relay devices are substantially synchronized.

2. The wireless network of claim 1 wherein the time interval information is communicated to said plurality of RFID devices,

whereby the timers of each of said plurality of RFID devices and of each of said plurality of relay devices are set to time substantially the same time interval;

and

wherein the synchronization information is communicated to said plurality of RFID devices to start the respective timers of said plurality of RFID devices substantially simultaneously,

whereby the time intervals of said plurality of RFID devices and said plurality of relay devices are substantially synchronized.

3. The wireless network of claim 1 wherein the time interval information, the synchronization information, or the time interval information and the synchronization information, does not include actual time information.

4. The wireless network of claim 1 wherein the time interval information defines a time interval that is substantially longer than a time in which said plurality of RFID devices and said plurality of relay devices are in receive/transmit mode.

5. The wireless network of claim 1 wherein the time interval information, or the synchronization information, or both, includes delay time information substantially defining a number of cycles of the receive/transmit mode so that the timers of the different ones of said plurality of RFID devices and said plurality of relay devices delay to enable the respective receive/transmit mode by the delay time, thereby to reduce transmission collisions.

6. The wireless network of claim 4:

wherein the delay time defines time slots that are separated by substantially the time required for a message to be transmitted and/or received;

or

wherein the delay time is controlled by the master device;

or

wherein the delay time is determined by each RFID device and/or each relay device, or

any combination of the foregoing.

7. The wireless network of claim 1 wherein the timers of said plurality of RFID devices and said plurality of relay devices exhibit tolerance, error and/or drift, and

wherein said master unit periodically communicates to said plurality of RFID devices and to said plurality of relay devices the synchronization information to start the respective timers of said plurality of RFID devices and said plurality of relay devices substantially simultaneously,

whereby the time intervals of said plurality of RFID devices and said plurality of relay devices remain substantially synchronized.

8. The wireless network of claim 1 wherein the messages include information relating to a location, tracking, a closed condition, a not closed condition, tampering, an intrusion, an environmental condition, a temperature, a pressure, a position, motion, acceleration, an impact, a distance, inertial information, a magnetic field, electrical continuity, an altitude, a physical parameter, moisture, humidity, a chemical, a medical parameter, a biological substance and/or agent, radioactivity, an optical condition, light, infrared, an image, an electromagnetic field, or any combination of the foregoing.

9. A method for operating a wireless network comprising a plurality of devices each having a powered down mode and a receive/transmit mode in which messages can be received and/or transmitted, and each including a timer operable in the powered down mode for enabling the receive/transmit mode periodically in response to time interval information, said method comprising:

designating one of the devices as a master device and defining a powered down time interval;

establishing a wireless network including the plurality of devices;

communicating time interval information representative of the powered down time interval to the plurality of devices of the wireless network;

whereby the timers of each of the plurality of devices are set to time substantially the same powered down time interval; and

communicating synchronizing information to the plurality of devices of the wireless network wherein the synchronizing information causes the respective timers of the plurality of devices to start substantially simultaneously,

whereby the powered down time intervals of the plurality of devices of the wireless network are substantially synchronized and are substantially the same.

10. The method of claim 9 wherein the time interval information, the synchronization information, or the time interval information and the synchronization information, does not include actual time information.

11. The method of claim 9 wherein the time interval information defines a powered down time interval that is substantially longer than a time in which the plurality of devices are in receive/transmit mode.

12. The method of claim 9 wherein said communicating time interval information, or said communicating synchronizing information, or both, includes communicating delay time information defining a number of receive/transmit mode time periods for causing the timers of different ones of the plurality of devices to delay to enable their respective receive/transmit modes by the delay time, thereby to reduce transmission collisions.

13. The method of claim 12:

wherein the delay time defines time slots that are separated by substantially the time required for a message to be transmitted and/or received;

or

wherein the delay time is controlled by the master device;

or

wherein the delay time is determined by each of the plurality of devices, or any combination of the foregoing.

14. The method of claim 9 wherein the timers of the plurality of devices exhibit tolerance, error and/or drift, further comprising:

periodically communicating the synchronizing information to start the respective timers of the plurality of devices substantially simultaneously,

whereby the powered down time intervals of the plurality of devices remain substantially synchronized.

15. The method of claim 9 wherein the messages include information relating to a location, tracking, a closed condition, a not closed condition, tampering, an intrusion, an environmental condition, a temperature, a pressure, a position, motion, acceleration, an impact, a distance, inertial information, a magnetic field, electrical continuity, an altitude, a physical parameter, moisture, humidity, a chemical, a medical parameter, a biological substance and/or agent, radioactivity, an optical condition, light, infrared, an image, an electromagnetic field, or any combination of the foregoing.

16. A method for operating a wireless network comprising a plurality of devices each having a powered down mode and a receive/transmit mode in which messages can be received and/or transmitted, and each including a timer operable in the powered down mode for enabling the receive/transmit mode periodically in response to time interval information, said method comprising:

designating one of the devices as a master device and defining a powered down time interval;

transmitting and receiving messages for establishing a wireless network including the plurality of devices;

communicating time interval information representative of the powered down time interval to the plurality of devices of the wireless network;

whereby the timers of each of the plurality of devices are set to time substantially the same powered down time interval;

communicating synchronizing information to the plurality of devices of the wireless network wherein the synchronizing information causes the respective timers of the plurality of devices to start substantially simultaneously and initiate powered down mode for the time interval,

whereby the powered down time intervals of the plurality of devices of the wireless network are substantially synchronized and are substantially the same,

at the end of the powered down time interval, placing the plurality of devices in receive/transmit mode for receiving and/or transmitting messages;

relaying messages transmitted by the plurality of devices;

processing the relayed messages for determining whether a given condition has occurred; and

if the given condition has occurred, providing an indication thereof.

17. The method of claim 16 further comprising:

returning to the powered down mode after said relaying messages, and, at the end of the powered down time interval, repeating the steps of;

placing the plurality of devices in receive/transmit mode for receiving and/or transmitting messages; and

relaying messages transmitted by the plurality of devices.

18. The method of claim 17 further comprising:

counting a number of cycles including the ends of the powered down time interval and the returning to the powered down mode; and

when the number of cycles reaches a predetermined number, repeating the step of communicating synchronizing information to the plurality of devices.

19. The method of claim 16 wherein said communicating time interval information, or said communicating synchronizing information, or both, includes communicating delay time information defining a number of receive/transmit mode time periods for causing the timers of different ones of the plurality of devices to delay to enable their respective receive/transmit modes by the delay time, thereby to reduce transmission collisions.

20. The method of claim 19:

wherein the delay time defines time slots that are separated by substantially the time required for a message to be transmitted and/or received;

or

wherein the delay time is controlled by the master device;

or

wherein the delay time is determined by each of the plurality of devices, or any combination of the foregoing.

21. The method of claim 16 wherein the given condition includes:

a location, tracking, a closed condition, a not closed condition, tampering, an intrusion, an environmental condition, a temperature, a pressure, a position, motion, acceleration, an impact, a distance, inertial information, a magnetic field, electrical continuity, an altitude, a physical parameter, moisture, humidity, a chemical, a medical parameter, a biological substance and/or agent, radioactivity, an optical condition, light, infrared, an image, an electromagnetic field, or any combination of the foregoing.