CANCELING SELF-JAMMER SIGNALS IN AN RFID SYSTEM

• US 20090002131A1
• Filed: 06/29/2007
• Published: 01/01/2009
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Chiu, Scott, Sajid, Mohammed, Kipnis, Issy
• Granted Patent: US 8,013,715 B2
• Time in Patent Office: Days
• US Class Current: 340/10.400
• 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; and

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.

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.

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; and

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

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

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