GEN2 Protocol

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GEN2 Protocol

• Son, Byung-guk
• Dept, of Computer Science
• Yonsei University

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Contents

• Terms and defines
• Tag Selection, Inventory, and access

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Terms and definitions

• Terms and definitions
• cover-coding
• interrogator obscures information that it is
  transmitting to a tag
• dense-interrogator environment
• 50 active interrogators operating in 50 available
  channels
• dense-interrogator mode
• A set of RgtT and TgtR signalling parameters used
  in dense-interrogator environment
• inventoried flag
• Indicate whether a tag my response to an
  interrogator
• Each of four session( A -gt B, B -gt A)

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Terms and definitions

• Terms and definitions
• Inventory round
• initiated by a Query command terminate by
  either a subsequent Query command or Select
  command
• multiple-interrogator environment
• 10 active interrogators operating in 50 available
  channels
• operating environment
• A region within which an interrogators RF
  transmissions are attenuated by less than 90dB
• Depends on environment (free space, building,
  etc)
• operating procedure (Tag-identification layer)
• The set of functions and commands used by
  interrogator to identify and modify tags

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Terms and definitions

• Terms and definitions
• random-slotted collision arbitration
• Tags load a random number into slot counter
• session
• An Interrogator chooses one of four sessions and
  inventories tags within that session
• single-interrogator environment
• A single active interrogator at any given time
• singulation
• Identifying an individual tag in a multiple-tag
  environment
• slot
• The value output by a tags slot counter

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Tag Selection, Inventory, and access

• Tag memory
• logically separated into four distinct banks

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Tag Selection, Inventory, and access

• Tag memory
• Reserved memory
• Contain the kill and/or access passwords
• UII memory (Unique Item Identifier)
• Contain a CRC-16, Protocol-Controls bits, a code
  that identifies the object (UII)
• TID memory
• Contain an 8-bit ISO/IEC 15963 allocation class
  identifier
• Contain sufficient identifying information for an
  interrogator to uniquely identify the custom
  commands ,optional features
• User memory
• Allow user-specific data storage

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Tag Selection, Inventory, and access

• Reserved Memory
• Kill password
• 32-bit value stored in Reserved memory 00h 1Fh
• Use kill password -gt kill the tag and render it
  nonresponsive
• Kill password 0 -gt not execute a kill
  operation, permanently read/write locked
• Access password
• Require an interrogator to issue the password -gt
  secured state
• Zero valued -gt permanently read/write locked
• UII Memory
• CRC-16
• Ensure validity of certain RgtT commands and TgtR
  replies

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Tag Selection, Inventory, and access

• UII Memory
• PC (Protocol Control) bits
• Contain physical-layer information that a tag
  backscatters with its UII during an inventory
  operation
• UII for EPCglobal applications
• UII structure is defined in the EPC Tag Data
  Standards
• UII for non-EPCglobal applications
• UII structure is defined in the ISO/IEC 15961
• TID Memory
• TID memory for EPCglobal applications
• 00h 07h E2h
• 08h 13h tag mask-designer identifier (from
  EPCglobal)

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Tag Selection, Inventory, and access

• TID Memory
• TID memory for EPCglobal applications
• 14h 1Fh vendor-defined tag model number
• Above 1Fh tag- and vendor-specific data
• TID memory for non-EPCglobal applications
• 00h 07h E2h or E0h
• Above 07h class-identifier value (ISO/IEC
  15963)
• User Memory
• User memory for EPCglobal applications
• Vendor defined and outside the scope of
  International Standard
• User memory for non-EPCglobal applications
• 00h 07h DSFID as defined in ISO/IEC 15961
• Encoding of User memory location above 07h
  ISO/IEC 15962

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Tag Selection, Inventory, and access

• Sessions and inventoried flags
• Provide 4 sessions (S0, S1, S2, S3)
• Participate in one and only one session during an
  inventory round
• Two or more interrogators can use sessions to a
  common tag population
• inventoried flag for each session (A or B)
• only resource a tag provides separately and
  independently to a given session
• Selected flag (SL)
• used in any session and is common to all
  sessions

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Tag Selection, Inventory, and access

• Tag states and slot counter
• Ready state
• Energized tags that are neither killed nor
  currently participating in an inventory round
• Receive a Query command -gt load number into slot
  counter
• Number is nonzero -gt transitions to the arbitrate
  state
• Number is zero -gt transitions to the reply state
• Arbitrate state
• Participating in the inventory round, but slot
  counter is nonzero
• Receive a QueryRep command -gt decrement its slot
  counter
• Slot counter is zero -gt transitions to the replay
  state

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Tag Selection, Inventory, and access

• Tag states and slot counter
• Reply state
• Backscatter an RN16 -gt receive ACK
• Fails to receive an ACK , receive an invalid ACK
  or an ACK with an erroneous RN16 -gt return
  arbitrate state
• Acknowledged state
• Transition to any state except killed
• Backscatter PC, UII and CRC-16
• Receive a valid ACK -gt re-backscatter PC, UII,
  CRC-16
• Fail to receive a valid command -gt return
  arbitrate state
• Open state
• Receive a Req_RN command in acknowledged state
• Backscattering a new RN16 (handle)
• Execute all access command except Lock

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Tag Selection, Inventory, and access

• Tag states and slot counter
• Secured state
• Receive a Req_RN command in the acknowledged
  state (access password is zero)
• Receive a Valid Access command in the open state
  (access password is nonzero)
• Execute all access command
• Transition to any state except open or
  acknowledged
• Killed state
• Receive a Kill command with a valid nonzero
  password (in either open or secured
  states)
• Disable a tag
• Slot counter
• Load a value between 0 and 2Q-1
• Q(0, 15) a query specifies Q, a QueryAdjust
  modifies Q

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Tag Selection, Inventory, and access

• Tag states and slot counter

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Tag Selection, Inventory, and access

• Managing tag populations

• Select
• Process by which an interrogator selects a tag
  population for inventory and access
• Inventory
• Process by which an interrogator identifies tags
• Transmitting Query command in one of four
  sessions
• Access
• Process by which an interrogator transacts with
  individual tags

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