READER FOR RFID AND RFID SYSTEM

Abstract

Provided is a reader for radio frequency identification (RFID) and a RFID system. A reader for RFID that receives a channel signal comprises a frequency oscillator generating an oscillating signal at a frequency that is offset by an offset frequency from a center frequency of the channel signal, a mixer mixing the channel signal with the oscillating signal that is offset, and a filter filtering a mixed frequency signal provided from the mixer. The reader for RFID and the RFID system are improved in reception for the wave identification using a listen before talk (LBT) mode for identifying an electronic tag.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are comprised to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 illustrates the configuration of a typical RFID system;

FIG. 2 illustrates a reader for RFID according to an embodiment of the present invention;

FIG. 3 illustrates exemplary spectrums to describe sequential operations of detecting power of a channel signal by the reader for RFID according to the embodiment of the present invention; and

FIG. 4 illustrates the configuration of a reader for RFID according to another embodiment of the present invention.

Claims

1. A reader for RFID (radio frequency identification) receiving a channel signal, the reader comprising: a frequency oscillator generating an oscillating signal at a frequency that is offset by an offset frequency from a center frequency of the channel signal;a mixer mixing the channel signal with the oscillating signal that is offset; anda filter filtering a mixed frequency signal provided from the mixer.

2. The reader for RFID of claim 1, wherein the filter comprises a DC (direct current) cut-off band that cuts off a DC component of the mixed frequency signal and a pass band at which the mixed frequency passes through.

3. The reader for RFID of claim 2, wherein the DC cut-off band includes a cut-off frequency less than the offset frequency.

4. The reader for RFID of claim 3, wherein the pass band includes a cut-off frequency less than a frequency obtained by adding one half of a band of the channel signal and the offset frequency.

5. The reader for RFID of claim 1, further comprising a compensator compensating the intensity of a frequency signal filtered at the filter.

6. The reader for RFID of claim 5, wherein the compensator comprises: an analog-to-digital converter converting the frequency signal filtered at the filter into a digital code; andan intensity indicator mapping the received frequency signal from the analog-to-digital converter with reference to the digital code converted at the analog-to-digital converter.

7. The reader for RFID of claim 1, wherein the channel signal is a signal to execute an LBT (listen before talk) mode.

8. The reader for RFID of claim 1, wherein the offset frequency is greater than approximately 10 KHz and less than one half of the channel signal band.

9. The reader for RFID of claim 1, wherein the received signal has a band ranging from approximately 908.5 MHz to 914 MHz.

10. A RFID system comprising: a reader claimed in claim 1; andan electronic tag.