Indisputable Key - Glossary

Synonyms

RFID Tranceiver

Related expressions

RFID Transponder, transponder applicator, RFID

Explanation

The RFID reader is a device that reads and writes information from/to the RFID transponders identifying the items and it acts as the first step in the link between the identification of an item in a supply chain and the associated database. Of all components of an RFID system, the RFID reader has probably the greatest influence on the reading distance and the overall resulting performance of the system.

The reader consists of:

an antenna or antennas for receiving and transmitting radio waves,
a receiver and a transmitter (the transmitter / receiver combination can also be called a transceiver),
a microprocessor for data processing and controlling the device.

The reader transmits a continuous signal at an UHF-frequency, which is called the carrier. The information is carried by this signal through a modulation of the signal. The data is coded and the carrier is modulated, i.e., modified, with the coded data signal. The reader antenna transmits this modulated signal. The carrier powers the transponder, which receives the information (read command) coded in the modulation and transmits the ID code in a similar way.
Radio waves reflect from metal and other surfaces. In such metallic environments, the reader may receive the modulated signal transmitted by the transponder but also the reflected carrier. The reflected carrier can mask the transponder signal as the power level is much higher and the receiver may be saturated because of the large unwanted signal.

RFID readers can be hand-held, portable, fixed or integrated: it depends on the application and on the operating environment.

Application/usage in Indisputable KEY

Different readers are needed along the forestry supply chain because different applications are concerned at different locations, characterised by different operating environments:

a reader will be integrated into the harvester head and possibly to the grapple of a forwarder.
fixed readers can be used in a saw mill to identify the logs to be sawn,
portable readers can be relocated where needed,
hand-held readers can be used to read manually a small number of transponders as the typical reading distance for hand-held readers is a few tens of centimetres.

The harvester head consists of many metallic parts and there can be a lot of reflections which generate trouble in the reading process. To avoid this, an adaptive RF-front end (transceiver) is developed for the forest RFID readers in the Indisputable KEY project. The adaptive RF-front end adapts to the environment by detecting the received reflected carrier and adjusting the transceiver operation so that the carrier is suppressed in the reception and thus the reception of the transponder signals is improved.

Institutions with teaching capabilities

RFID Lab is a Finnish application center for RFID technology, especially focusing on logistics systems. RFID Lab Finland offers neutral information, consulting, training and measuring services to the interested parties in Finland.

OTA Training LLC (US) offers RFID training courses worldwide (web based training, in a classroom or in a RFID facility). OTA was chosen as one of the 20 Leading RFID Innovators in 2008.

Available text books and training material

“ KST’s RFID Reader Guide 2004” David Zhou ”: this guide covers over 100 different RFID readers from about 40 RFID reader manufacturers worldwide. About 80 reader product images are also included in the book.

“ Method and system for optimizing RFID reader operation ”, WO2007067374, Symbol Technologies Inc. (US) : this invention generally relates to RFID and more specifically relates to an RFID reader.

White Paper: “ Synchronization of RFID Reades for Dense RFID Reader Environments ” from Institute of Electrical and Electronics Engineers, 2006.

See also:

http://www.rfidjournal.com
http://www.teamrfid.com