A Data Protocol for RFID Systems: ISOIEC 15961

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A Data Protocol for RFID SystemsISO/IEC 15961
15962

• Prepared as an Update of
• ISO/IEC JTC1 SC31 WG4 SG1s Work
• Oct 2003

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ISO/IEC STANDARDISATIONSC 31 Structure
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JTC1 SC31 WG4 RFID for Item ManagementRelevant
Work Items

• SG3 responsible for
• ISO/IEC 18000 series air interface standards at
  lt135 KHz 13.56 MHz 433 MHz 860 - 960 MHz 2.45
  GHz
• SG1 responsible for
• ISO/IEC 15961 data protocol - application
  interface
• ISO/IEC 15962 data protocol - data encoding rules
• NEW Application Program Interface standard

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ISO/IEC 15961 15962 DATA PROTOCOLWhat WG4 SG1
Had to Consider

• SG1 was given its tasks before technology
  submissions were resolved by SG3
• SG1 worked on the basis that there are no
  restrictions of
• how frequencies can be combined in applications
• which air interface protocols are standardised
• tag architecture and functional capability
• Common channel encoding schemes could be
  developed
• The deliverable from SG1 had to be (generally)
  independent of technology features and
  constraints,
• yet be open ended to new technologies
• and application requirements

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ISO/IEC 15961 15962 Connectivity
ModelIntegrating Applications and Technology
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ISO/IEC 15961 15962 Connectivity
ModelIntegrating the Real World
ISO/IEC 15459
ANS MH10 Data Identifiers
ISBT blood transfusion
OTHERS..
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WG4 SG1s APPROACHCreative Thinking

• Support 1 of 2 (or more) data objects with
  selective read and/or write
• Conceived logical memory map, which is
  independent of tag architecture, which is
  specified as Access Method
• Adapted tag selection technique (Application
  Family Identifier) from smart card technology
• Provided support for different data formats
• Developed specific data compaction schemes for
  all tag types
• Defined that commands could be specified as
  objects, separate from data objects

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ISO/IEC 15961ASN.1 Description

• ASN.1 is an abstract syntax
• effectively a data definition language
  independent of these - hence abstract
• specified in ISO/IEC 8824 -1 to 4
• ASN.1 has associated transfer syntaxes
• effectively a set of encoding rules
• transfer syntax applies to presentation layer of
  OSI model
• specified in ISO/IEC 8825 -1 and 2
• ISO/IEC 15961 uses Basic Encoding Rules (BER)
• transfer may be achieved without ASN.1 compilers

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ISO/IEC 15961 15962 Data ProtocolObject
Identifiers

• Object identifiers used for selective read /
  write
• Based on ISO/IEC 9834-1 established rules and
  structures
• ISO/IEC 9834-1 allows systems to define objects
  to any level of granularity - just need an object
  ID
• The object tree ensures uniqueness of objects
• Therefore, possible to encode different data,
  including closed system objects with no risk of
  corruption
• Extension techniques make the system totally
  expandable

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ISO/IEC Air Interface Data ProtocolSystem
Information

• This provides a protocol level - not data -
  method for managing the interface between
  application and RF tag, and includes
• Application Family to enable a subset of RF tags
  to be in the communication channel
• Data Format to specify the interpretative nature
  of the encoded bytes on the RF tag
• Access Method to create a logical structure of
  the bytes encoded on the RF tag

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ISO/IEC Air Interface Data ProtocolSystem
Information Application Family

• Addresses real need to manage the transactions
  across the air interface
• with large population of tags
• where there is a risk of different types of tag
  being present
• To be compatible with smart card rules (SC17),
  RFID for Item Management has 60 Application
  Family codes
• Application Family codes to be allocated to focus
  on a meaningful subset within the system, thus
  excluding RF tags from other systems
• So far only 14 codes have been assigned covering
  all major RFID for Item Management applications,
  leaving 75 spare capacity of the initial block

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ISO/IEC 15961 15962 Data ProtocolSystem
Information Data Format

• Full feature - any combination of Object ID
• Application specific to include
• EANUCC
• Data Identifiers for primary industry e.g.
  Automotive
• IATA for baggage handling
• Universal Postal Union
• ISO/IEC 15459 unique identifiers
• others (if required)
• The list can be extended to bring RFID benefits
  to different applications without abandoning
  legacy data

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ISO/IEC 15961 15962 Data ProtocolSystem
Information Access Method

• Access Methods defined
• no directory
• directory
• self-organising tag (near future development)
• Future developments, e.g. data sensory
  information (near future development), are
  dependent on new functionality and application
  requirements

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ISO/IEC 15961 15962 Data ProtocolSame RF tag
Configured to Different Structures
No Directory Directory
Legend P Precursor OID Object Identifier
O (data) object
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WG4 SG1 DATA PROTOCOLApplication Command -
Overview
HOST
INTERROGATOR Encoder Decoder Command Processor
TAG

• 15961 High Level Application Commands
• exchanged between host and interrogator
• data incorporated within commands and responses
• object based (name, type, length, value)
• 18000 Low Level Commands
• requires particular tag drivers
• can selectively support application commands,
  because 15961 response deals with this

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WG4 SG1 DATA PROTOCOLApplication Command -
Overview

• Currently 16 application commands specified,
  covering
• Configure and abstract System Information
• Add (write) one or more data objects
• Read one or more data objects, including read
  first object (to read licence plate)
• Modify (read, overwrite) one data objects
• Inventory tags, including read defined data
• Read memory (technical audit)
• Erase memory

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ISO/IEC 15962Data Compaction Schemes

• The ISO/IEC 15962 process looks, on a case by
  case basis, at the type of data to be written as
  a data object to the tag.
• It selects the most efficient encoding scheme
  from the following alternatives (the potentially
  most efficient scheme is at the top of this list)
  
• Integer encodes number as binary
• Numeric 4 bits per digit
• 5-bit uppercase alphabetic
• 6-bit uppercase alphabetic, numeric, etc
• 7-bit all ISO 646 (US ASCII)
• Octet unaltered 8-bit

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WG4 SG1 DATA PROTOCOL Data Transfer
HOST
INTERROGATOR Encoder Decoder Command Processor
TAG
Host-to-interrogator Full Object ID Uncompacted
data Logical Memory tag structure is assumed for
location of octets
Interrogator-to-tag Uncompacted Object ID or
(Root Relative) ID Compacted data Location of
octets completely based on tag architecture
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ISO/IEC 15961Support for Unique Identifier

• ISO/IEC 18000 series have air interface commands
  to read blocks 1n
• The data protocol standards have an application
  command to read the first object
• Therefore can support
• unique identifier
• unique identifier attribute (concept close to
  EAN.UCC Composite Symbology)
• have option for directory and no-directory
  structure

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ISO/IEC 15961 15962 Data ProtocolApproach to
Legacy Data Formats

• Legacy data formats are accepted
• For EANUCC this can apply to any data including
  SSCC for transport units, GRAI,etc
• IATA may continue to use its bag tag Id and other
  attribute data
• ISBT may continue to use its alphanumeric 14
  character code
• Various other ISO formats can be supported that
  enable RFID or alternative data carriers to be
  integrated
• and so on

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ISO/IEC 15961 15962 for ISO/IEC 15459

• The ISO/IEC 15459 track trace code (as defined
  by SC31/ WG2) has its Object Identifier applied -
  a simple routine
• The 15459 code may be any of the permitted
  formats
• The use of a specific data identifier eliminates
  the need to encode the Object Identifier itself
• The 15459 code value is compacted for efficient
  encoding and transmission, but re-constructed by
  the data protocol so that it is compatible with
  existing systems
• Any attribute data may be added
• If encoded in an RF tag in the first position, a
  specific application command can pull the 15459
  code as a licence plate whether attribute data is
  encoded or not

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Thank You

• Any questions?