Also, how could payment be processed in such a deployment?
Passive ultrahigh-frequency (UHF) RFID technology would be the most likely way in which a retailer would implement automated checkout. Many apparel items are being tagged at the source with passive UHF tags, and stores are using these to manage inventory. The key issue is how to link an individual passive UHF transponder on a specific item to a particular buyer. Since there are no cell phones with passive UHF RFID readers built into them at present, some other method must be utilized.
You could have customers walk to a kiosk and pay with a credit card, and then have a reader in the kiosk interrogate the card's RFID transponder and indicate in the store's database that each item was sold. That way, as shoppers walked out, the tags on their purchased items would be read via RFID readers located at the store exit, and no alarm would be sounded since the products detected would be paid for. This would not be an ideal scenario, however, since the aim would be to eliminate the checkout process.
Another way might be to encode the serial number in each tag—the Electronic Product Code (EPC)—in a QR code and have the customer read each product's QR code, pay for that item and then have his or her cell phone send payment data to the store's back-end system. The serial number in the QR code would be marked as being on a paid-for item, so no alarm would sound as that customer walked out.
Another way might be to offer a smartphone app that used Bluetooth beacons. A customer could buy an item in the store, and the type of item—a medium-sized, blue Polo shirt, for instance—would be recorded as having been purchased by that individual. His or her phone would send a signal via Bluetooth to a Bluetooth beacon near the exit that he or she was approaching with that shirt, and the shopper could thus walk out without an alarm sounding.
Eventually, passive UHF RFID readers will be built into smartphones. Once that happens, customers will be able to use them to buy and check out items automatically.
—Mark Roberti, Founder and Editor, RFID Journal