Editing Radio-frequency identification (section)

===Bulk reading===
"Bulk reading" is a strategy for interrogating multiple tags at the same time, but lacks sufficient precision for inventory control. A group of objects, all of them RFID tagged, are read completely from one single reader position at one time. However, as tags respond strictly sequentially, the time needed for bulk reading grows linearly with the number of labels to be read. This means it takes at least twice as long to read twice as many labels. Due to collision effects, the time required is greater.<ref>{{cite web|url=https://www.rfidjournal.com/site/faqs|archive-url=https://web.archive.org/web/20130328095357/http://www.rfidjournal.com/site/faqs|archive-date=March 28, 2013|title=Frequently Asked Questions|website=www.rfidjournal.com|access-date=2019-04-22}}</ref>

A group of tags has to be illuminated by the interrogating signal just like a single tag. This is not a challenge concerning energy, but with respect to visibility; if any of the tags are shielded by other tags, they might not be sufficiently illuminated to return a sufficient response. The response conditions for inductively coupled [[High frequency|HF]] RFID tags and coil antennas in magnetic fields appear better than for UHF or SHF dipole fields, but then distance limits apply and may prevent success.{{Citation needed|reason=See talk page|date=July 2021}}<ref>{{Cite book|last=Paret|first=Dominique|title=RFID at ultra and super high frequencies: theory and application}}</ref>

Under operational conditions, bulk reading is not reliable. Bulk reading can be a rough guide for logistics decisions, but due to a high proportion of reading failures, it is not (yet){{When|date=January 2021}} suitable for inventory management. However, when a single RFID tag might be seen as not guaranteeing a proper read, multiple RFID tags, where at least one will respond, may be a safer approach for detecting a known grouping of objects. In this respect, bulk reading is a [[Fuzzy mathematics|fuzzy]] method for process support. From the perspective of cost and effect, bulk reading is not reported as an economical approach to secure process control in logistics.<ref>{{cite web|url=http://www.nerc.com/files/SGTF_Report_Final_posted_v1.1.pdf|title=STGF Report}}</ref>