FCC RFID Workshop RFID DiscussionsSeptember 7, 2004 Kevin Powell, Symbol Technologies
Pilots with eight key suppliers Wal-Mart's RFID-Using Suppliers to Exceed 100 eWeek June 14, 2004 Convergence around the Electronic Product Code (EPC) as the standard Defense Department will require its suppliers to put RFID tags on shipments by January 2005 to better manage its inventory. EPC Pallet and case tagging mandates – PASSIVE tags Aviation Week Defining the Gen 2 Standard RFID Market Direction
EPC Standards Glossary • Class 0 (available): • Generation 1, protocol 0 • Factory programmed ID • Class 1 (available): • Generation 1, protocol 1 • Write Once ID • UHF Generation 2 (future): • Single Gen2 protocol • Variety of memories & features • First products in 2005
Readers and Antennas AR400 Reader General Purpose Antenna SR400 Reader High Performance Antenna
Handheld with RFID Supports: Same ruggedness and ergonomic as the MC-9000G Antenna (front-mounted) and additional electronics add the ability to read and write either EPC Class 0 or Class 1 RFID tags Integratedwireless networking 1D bar codes & 2D bar code RFID simultaneously “all in one”
EPC-Compliant RFID Tags Plastic Tag Carton Tag Plastic Bottle Tag Glass Tag Concrete Tag Variety of tags for different materials and applications Generic Tag Class 0/0+
} EPC Class 0 (Invented by Matrics) EPC Class 1 (Invented by Alien Technologies) EPC Gen2 under development Three EPC Communication Protocols for UHF Basics - RFID System RFID Protocols Memory Power recovery RF demodulator RadioSignal RF modulator Digital logic Oscillator Passive RFIDTag Reader commands the tag & simultaneously listens for responses All in 10 microwatts! A tag stores information and exchanges it by radio signal
Passive RFID System Design • Passive Tag Constraints • Battery-less – RF field powered ONLY, thus: • Total consumed power < 10 mW (10M range), and • Simple demodulator (amplitude – 1bit/Hz style) • Simple modulator (1 transistor – square wave out) • Backscatter (modulated RCS) only Tx method • Passive Tag Results • Very wide band response (effective antenna BW) in receiver as well as backscatter(but at low levels) • Confined to relatively inefficient reader modulation encoding methods (simple tag demod).
Passive RFID System Design • Reader Constraints • Must energize tag (transmit) while in receive mode • = Receive –50dBm while transmitting +30dBm • Avoid noise sources • Reader transmit & receive circuitry • Other backscatter sources, ie fluorescent lighting • Reader Results • Extremely low noise design necessary to properly receive tag signals while transmitter is on. • Detect and avoid other high power RF devices. • Shift receiver away from noise sources.
Channel Edge Channel Edge Reader CW Tag - baseband Tag – Class 0 Subcarriers Fluorescent 20-40kHz Tag – Gen2 Subcarriers RFID Frequency Sources Reader Tx
Passive RFID Trends • Better tag designs/protocols = lower power • Note – Fluorescent interference approx –60dBm
Gained Knowledge • Reader signals interfere with tag signals at thousands of feet separation. • Reader signals interfere with other reader transmissions at less than 100 feet. • 80-100 dB range between Reader and Tag leads design to a separation of disparate power levels such that: • Reader signals ONLY contend w/ other readers • Tag signals ONLY contend with other tags
Conclusions, Requests • As technology improves tag distances, the impact of noise (self, and fluorescent) becomes severe; the available technology is near the limit. • Technology improvement comes on the heels of the ability to remove the tag response from noise. • Request - allow readers on even channels, tag response on odd channels (or similar) as an optional channel use model.
Thank You Questions? ?