# US 8,542,101 B2 · Data recovery method and apparatus for radio frequency identification

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- Number: US 8,542,101 B2
- Document ID: US8542101B2
- Status: Granted
- Kind: B2
- Application number: 11/585,982
- Filed: 2006-10-25
- Published: 2008-01-03
- Granted: 2013-09-24
- Earliest claimed: 2006-06-29
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Ji-hun Koo; Woo-shik Kang; Kyung-ho Park
- Inventors: Ji-hun Koo; Woo-shik Kang; Kyung-ho Park
- Web page: https://patentgrep.com/patent/US8542101B2

## CPC

- G06K 7/0008: {General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer}
- G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS

## Abstract

Provided are an RFID reader and a data recovery method which selectively selects only an integrity-checked phase signal, when receiving a backscattered signal of an RFID tag through an I signal path or a Q signal path, and may reduce a shadow area of a read range. The RFID reader includes a signal receiver which receives a plurality of phase signals; a symbol detector which recovers data with respect to each of the received phase signals; and a signal selector which selects a signal that satisfies a predetermined standard, from the data-recovered phase signals.

## Claims

### Claim 1

A radio frequency identification (RFID) reader comprising:
a signal receiver of the RFID reader, which receives a plurality of phase signals;
a symbol detector which recovers data with respect to each of the received phase signals; and
a signal selector which selects a signal that satisfies a predetermined standard, from the data-recovered phase signals,
wherein the predetermined standard is satisfied by the signal selector selecting a phase signal which comprises an integrity-checked preamble signal of each of an I signal path and a Q signal path.

### Claim 2 (depends on 1)

The RFID reader of claim 1, wherein the symbol detector tracks a symbol from each of the received phase signals, and recovers the tracked symbol by using a predetermined pattern matching method.

### Claim 3 (depends on 2)

The RFID reader of claim 2, further comprising:
a preamble checker which checks the integrity of the recovered data.

### Claim 4 (depends on 3)

The RFID reader of claim 3, wherein the preamble checker detects a preamble signal from the recovered symbol, and checks the integrity.

### Claim 5 (depends on 3)

The RFID reader of claim 3, wherein the signal selector selects the integrity-checked phase signal from the plurality of phase signals.

### Claim 6 (depends on 1)

The RFID reader of claim 1, wherein each of the received phase signals comprises an I phase signal and a Q phase signal.

### Claim 7

A data recovery method comprising:
receiving, at a radio frequency identification (RFID) reader, a plurality of phase signals;
recovering data with respect to each of the received phase signals; and
selecting a signal, which satisfies a predetermined standard, from the data-recovered phase signals,
wherein the predetermined standard is satisfied by selecting a phase signal which comprises an integrity-checked preamble signal of each of an I signal path and a Q signal path.

### Claim 8 (depends on 7)

The method of claim 7, wherein the recovering comprises:
tracking a symbol from the plurality of phase signals; and
recovering the tracked symbol by using a predetermined pattern matching method.

### Claim 9 (depends on 8)

The method of claim 8, further comprising checking the integrity with respect to the recovered data.

### Claim 10 (depends on 9)

The method of claim 9, wherein the checking comprises detecting a preamble signal from the recovered symbol.

### Claim 11 (depends on 9)

The method of claim 9, wherein the selecting selects the integrity-checked phase signal from the plurality of phase signals.

### Claim 12 (depends on 7)

The method of claim 7, wherein each of the phase signals comprises an I phase signal and a Q phase signal.

### Claim 13

A non-transitory computer-readable recording medium storing a program for implementing a method comprising:
receiving, at a radio frequency identification (RFID) reader a plurality of phase signals;
recovering data with respect to each of the received phase signals; and
selecting a signal which satisfies a predetermined standard, from the data-recovered phase signals,
wherein the predetermined standard is satisfied by selecting a phase signal which comprises an integrity-checked preamble signal of each of an I signal path and a Q signal path.