Wake Up Device for Communications System

• US 20070285214A1
• Filed: 08/22/2007
• Published: 12/13/2007
• Est. Priority Date: 07/15/1993
• Status: Active Grant

• Current Assignee: Round Rock Research LLC
• Original Assignee: Keystone Technology Solutions, LLC
• Inventors: Rotzoll, Robert
• Granted Patent: US 7,912,443 B2
• Time in Patent Office: Days
• US Class Current: 340/10.340
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: H04W 52/0293 having a sub-controller with a low clock frequency switching on and off a main controller with a high clock frequency
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention teaches a communications system comprising a first communications device for receiving data and a wake up signal. The first communications device comprises an active mode of operation and a sleep mode of operation for reducing power consumption. Further, the system comprises means for switching the first communications device to and from sleep mode in response to receiving the wake up signal. Further, the system comprises a second communications device for transmitting data to the first device during its active mode, while transmitting the wake up signal to the first device during its sleep mode.

Claims

1. A system to track a radio frequency identification (RFID) tag, the system comprising:

a first antenna;

an interrogator communicatively coupled to the first antenna, the interrogator configured to transmit a wake signal and a sleep signal at a first frequency, and the wake signal being transmitted at a first data rate and the sleep signal having a second data rate, the first data rate being different than the second data rate; and

an RFID tag having a second antenna, communications circuitry, and a battery, the communications circuitry including circuitry to receive the wake signal at the first frequency and the first data rate and the sleep signal at the first frequency and the second data rate, the RFID tag being configured to operate in a first mode upon receipt of the wake signal and to operate in a second mode upon receipt of the sleep signal, the second mode requiring less power than the first mode.

2. The system of claim 1, wherein the RFID tag is configured to continue to operate in the first mode after receiving the wake signal until receiving the sleep signal.

3. The system of claim 1, wherein the circuitry to receive the wake signal includes a data rate circuit.

4. The system of claim 3, wherein the data rate circuit includes a bandpass filter and an envelope detector.

5. The system of claim 1, wherein the RFID tag further comprises circuitry to receive one or more additional wake signals at other frequencies.

6. The system of claim 1, wherein the RFID tag further comprises a switch circuit and a master receiver, the switch circuit being communicatively coupled between the communications circuitry and the master receiver, wherein the switch circuit maintains the master receiver in the first mode until the communications circuitry detects the sleep signal and maintains the master receiver in the second mode until the communications circuitry detects the wake signal.

7. A system to track a radio frequency identification (RFID) tag, the system comprising:

a first antenna;

an interrogator communicatively coupled to the first antenna, the interrogator configured to transmit a wake signal and a sleep signal at a first frequency; and

an RFID tag having a second antenna, communications circuitry, and a battery, the communications circuitry including circuitry to receive the wake signal at the first frequency and the sleep signal at the first frequency, the RFID tag being configured to remain in a sleep mode until the communications circuitry determines the wake signal has been received and transitioning into a wake mode after the wake signal has been received, the communications circuitry determining the wake signal has been received at least in part by determining that an incoming signal has at least a first characteristic and a second characteristic, the sleep mode requiring less power than the wake mode.

8. The system of claim 7, wherein the first characteristic is a frequency and the second characteristic is a data rate.

9. The system of claim 7, wherein the communications circuitry is further configured to transition the RFID tag from the wake mode to the sleep mode upon receipt of the sleep signal.

10. The system of claim 7, wherein the communications circuitry comprises a plurality of data rate detector circuits.

11. The system of claim 10, wherein each of the plurality of data rate detector circuits includes a bandpass filter and an envelope detector.

12. The system of claim 10, wherein each of the plurality of data rate detector circuits detects a different data rate of an incoming signal.

13. A radio frequency identification (RFID) tag comprising:

an antenna;

a signal receiver communicatively coupled to the antenna and configured to receive an incoming signal and to demodulate the incoming signal, thereby generating a demodulated signal;

a plurality of detectors communicatively coupled to the signal receiver to receive the demodulated signal, each of the plurality of detectors being configured to detect at least a first characteristic and a second characteristic of the demodulated signal, each of the plurality of detectors configured to detect the first characteristic and the second characteristic such that at least one of the first characteristic and the second characteristic is different than other detectors; and

a data processor communicatively coupled to the plurality of detectors, the data processor configured to operate in a first mode upon receiving a first signal from a first detector and to operate in a second mode upon receiving a second signal from a second detector, the first mode and the second mode requiring different power levels.

14. The RFID tag of claim 13, wherein the first detector is configured to generate the first signal upon detecting a first frequency as the first characteristic and a first data rate as the second characteristic and the second detector is configured to generate the second signal upon detecting a second frequency as the first characteristic and a second data rate as the second characteristic, the first data rate being different than the second data rate.

15. The RFID tag of claim 14, wherein the first frequency is substantially equivalent to the second frequency.

16. The RFID tag of claim 13, wherein each of the plurality of detectors includes a bandpass filter and an envelope detector.

17. The RFID tag of claim 13, wherein the signal receiver comprises a bandpass filter and an envelope detector.