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utilizing physical layer information to improve rfid tag

utilizing physical layer information to improve rfid tag

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2.1 RFID Reader<br />

CHAPTER 2<br />

PASSIVE UHF RFID SYSTEMS<br />

Figure 2.1. RFID system setup.<br />

UHF RFID systems use the EPC Class 1 Gen. 2 pro<strong>to</strong>col which is a reader<br />

talks first pro<strong>to</strong>col. The reader therefore controls the entire identification process and<br />

so is an important component of the system. It is the readers job <strong>to</strong> power up the<br />

<strong>tag</strong>s by sending a carrier wave whose frequency lies in the ISM band. RFID readers<br />

amplitude shift keying or phase shift keying. Readers energize the <strong>tag</strong>s in their field<br />

and identify them by starting an inven<strong>to</strong>ry round. Upon successful completion of<br />

the round the reader has a list of the EPC ids of each <strong>tag</strong>. This EPC is a unique<br />

96-bit number which identifies every <strong>tag</strong>. The reader then sends this <strong>information</strong><br />

<strong>to</strong> the middleware which retrieves the product <strong>information</strong> from a central database.<br />

5

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