epcglobal class-1 generation 2 uhf rfid todd humes, cto impinj, inc. 501 n 34 th street, suite 100...
TRANSCRIPT
EPCglobal Class-1 Generation 2
UHF RFID
Todd Humes, CTOImpinj, Inc.
501 N 34th Street, Suite 100 Seattle, WA 98103
More transistors than the processor in a 1985 IBM PC-AT
Lower power consumption than a honeybee’s brain
An RFID Chip
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RFID Hardware Overview
Wafers
Tags
Reader
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RFID is Old, what’s New
• New standards at UHF (900 MHz) vs HF (13.56MHz)• UHF - 10X range of HF RFID• Faster data rates – up to 640kbps
• But, presents many new challenges:• How to identify and read/write single tags from hundreds
within a reader field...• Tag and reader RF interference...• Security....• Tag data processing...
• Solution - EPCglobal Gen2 standard
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RFID Systems
RFID Reader
IP
Network
Tag
Tag
Tag
Tag
Example data exchange:
Forward
Return
Link parameters
Tag inventory
Link rates and encoding formats
Singulation parameters, tag identification
Network layer Air Interface
RFID Reader
RFID Reader
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Tag Identification
• Suppose…you are all tags• You are all blindfolded• You are nearly deaf• You talk by whispering• You can’t hear each other
• Suppose…I’m a reader• I’m blindfolded• I don’t know who is in the room• I need to yell so you can hear me• If two of you talk at once, I can’t understand you• I’m not allowed to say your name• I may hear many others like me screaming in the same
room
• I need to identify everybody in the room
What do I do?
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Reader Environments
• Operating Environment• A region within which a reader’s RF transmissions are
attenuated by less than 90dB (roughly a sphere with a 1km radius)
• Single-reader environment• A single reader operating in the environment
• Multiple-reader environment• # of simultaneously active readers < # of available
channels• Example: 10 readers operating in 50 channels
• Dense-reader environment• # of simultaneously active readers # of available
channels• Example: 50 readers operating in 50 channels
Readers require knowledge of operational deployment and the ability to adjust their RF parameters for a given
environment -ie. One non-dense reader in a dense reader deployment will spoil the whole frequency plan
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Air Interface Control
Gen2 features
Purpose S/W Control
Tag selection and identification
Singulation control and options for faster inventories
Q-algorithm, Boolean selection, truncated replies
Dense reader mode Allows for a large number of closely spaced readers with minimal interference and optimized data rate for high noise or high speed comm
Forward link options – DSB-ASK, SSB-ASK, PR-ASK Return link options – Baseband or subcarrier backscatter
Sessions Multiple readers talk within same tag population
e.g. dock door reader + handheld
Choice of four sessions
Variable data rates Link closure in varied environments
Configure forward link (Tari, pulsewidth) and reverse link (preamble type, data rate, encoding - FMO or Miller)
Kill and access password
Security Password validation and management