Canceling self-jammer signals in an RFID system

• US 8,013,715 B2
• Filed: 06/29/2007
• Issued: 09/06/2011
• Est. Priority Date: 06/29/2007
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Sajid, Mohammed, Kipnis, Issy, Chiu, Scott
• Primary Examiner(s): Bugg; George
• Assistant Examiner(s): Dorsey; Renee
• Application Number:
  US11/771,231
• Publication Number:
  US 20090002131A1
• Time in Patent Office: 1,530 Days
• Field of Search: None
• US Class Current: 340/10.3
• CPC Class Codes: H04Q 2209/47 using RFID associated with sensors
• CPC Class Codes: H04Q 2209/75 by polling or interrogating the sub-stations
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A device and method for canceling one or more self-jammer signals in a radio-frequency identification system.

Claims

1. A method for canceling self-jammer signals in a radio frequency identification (RFID) system, comprising:

generating a first radio-frequency signal comprising a signal generated at a local oscillator of an RFID reader;

transmitting the first radio-frequency signal;

receiving a second radio-frequency signal comprising one or more self-jammer signals, the one or more self-jammer signals comprising the transmitted signal;

detecting characteristics of the one or more self-jammer signals;

generating a self-jammer cancellation signal comprising the signal generated at the local oscillator and based, at least in part, on the detected characteristics of the one or more self-jammer signals;

canceling the one or more self-jammer signals in a cancellation loop, wherein canceling the one or more self-jammer signals comprises out-phasing the self-jammer signal with the self-jammer cancellation signal; and

shifting a phase of a transmit signal based at least in part on characteristics detected in the detection circuit.

2. The method of claim 1, wherein generating the self-jammer cancellation signal further comprises shifting the phase of the self-jammer cancellation signal based, at least in part, on the detected characteristics of the one or more self-jammer signals.

3. The method of claim 1, wherein generating the self-jammer cancellation signal further comprises adjusting the amplitude of the self-jammer cancellation signal based, at least in part, on the detected characteristics of the one or more self-jammer signals.

4. The method of claim 1, wherein generating a first radio-frequency signal further comprises shifting the phase of the signal generated by the local oscillator 180 degrees.

9. The method of claim 2, wherein generating the self-jammer cancellation signal further comprises adjusting the amplitude of the self-jammer cancellation signal based, at least in part, on the detected characteristics of the one or more self-jammer signals.

10. The method of claim 9, wherein generating a first radio-frequency signal further comprises shifting the phase of the signal generated by the local oscillator 180 degrees.

11. The method of claim 3, wherein generating the self-jammer cancellation signal further comprises shifting the phase of the self-jammer cancellation signal based, at least in part, on the detected characteristics of the one or more self-jammer signals.

12. The method of claim 11, wherein generating a first radio-frequency signal further comprises shifting the phase of the signal generated by the local oscillator 180 degrees.

5. An apparatus capable of canceling self-jammer signals, comprising:

a self-jammer cancellation circuit for canceling a self-jammer signal using a signal generated by a local oscillator, wherein the self-jammer cancellation circuit comprises;

a receiver coupled to a detection circuit, the receiver capable of receiving a radio-frequency signal comprising one or more self-jammer signals and further capable of communicating the radio-frequency signal to the detection circuit;

the detection circuit coupled to a local oscillator, the detection circuit capable of detecting characteristics of the one or more self-jammer signals and communicating the characteristics to a controller of the local oscillator;

the local oscillator coupled to a summing node, the local oscillator capable of generating a self-jammer cancellation signal;

the summing node capable of out-phasing the one or more self-jammer signals with the self-jammer cancellation signal; and

a transmitter coupled to the detection circuit, the transmitter comprising an up-conversion mixer capable of shifting a phase of a transmit signal based at least in part on characteristics detected in the detection circuit.

6. The apparatus of claim 5, further comprising a mixer coupled to the local oscillator capable of shifting the cancellation signal 180 degrees out of phase with the one or more self-jammer signals.

7. The apparatus of claim 5, wherein the receiver further comprises an antenna for receiving the radio-frequency signal.

8. The apparatus of claim 6, wherein the receiver further comprises an antenna for receiving the radio-frequency signal.