RFID Systems:
Status of the RFID Standardization
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Good reasons for the standardization
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RFID standardization for goods labeling, the cornerstone for open logistics processes
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Determining criteria for the selection of the proper RFID standard
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Possible differentiation of products according to application
Through standardization, it is hoped that order will be established in the maze of RFID systems.
Users are looking forward to a standard that will provide clear answers to which system and which
frequency is best suited for his or her application. Without investment protection, fewer and fewer
customers are willing to spend money on RFID.
What does standardization achieve?
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Increased acceptance at the customer
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Increased competition through comparability
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A second source creates independence
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Investment protection for customers and producers
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Open systems: global use becomes possible
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Integration of the entire supply chain
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Realistic prices through variety of choices
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Increased quantities result in cost reduction
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Concentration on basic technologies
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Strengthening of the position opposite regulatory agencies
Standardization sets uniform procedures and parameters for users and providers, ensuring that
different – but standard-conforming products – can communicate with each other and behave
similarly. As a result, a uniform basis is created, enabling open and global processes. Particularly
for the subjects of goods labeling and materials flow control – which span across many elements
of the supply chain – labeling methods and devices are required that conform to “a” standard.
Standardization means coordinating numerous ideas and interests. But this is not enough. In the
case of RFID, strong restrictions imposed by national and international regulatory agencies exist
for the allocation of frequency bands. In Europe, the highest authority is held by the CEPT
(European Conference of Postal and Telecommunications Administrations) with the ETSI
(European Telecommunications Standards Institute) responsible for standardization activities. Its
counterpart in the USA is the FCC (Federal Communications Commission). For the
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standardization specification itself, the ISO (International Organization for Standardization) is
responsible. This means that many suggestions for the standardization of RFID systems only
make sense, if the corresponding approval prerequisites can be met. A current example for this is
the discussion centered around a free UHF range frequency band for RFID applications in Europe.
What good would a globally valid specification on the subject of EPC have done, if the possible
applications were regulated markedly different in Europe than the USA?
Illustration: Standardization versus Diversification
Universally critical for the standardization are the subjects of diversification and innovation.
Naturally, providers of RFID products try to turn the tide in their favor by offering more
features/services or special functions. Innovations, too, can jeopardize the often lengthy
standardization processes. This, though, illustrates the necessity of having developments –
innovations in particular – be compatible with existing standards or – if required – even adapt
standards to new possibilities and needs.
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Illustration: RFID Approval Conditions in Europe
The inllustions above shows – plotted logarithmically – the frequency range for RFID systems from
50 kHz to 10 GHz, which can be used economically today. Listed are the applicable approval
regulations.
In this vast range, however, there exist only a few spots at which RFID transmissions of
appropriate radiation values are permitted without license. By adhering to the respective limit
values, these areas are freely accessible and also free of so-called primary users such as
radio/TV stations or wireless communication services and cellular phone operators. These
“frequency needles” obviously lent themselves as permissible frequencies to the standardization
of the air interface for the goods identification.
From a transmission behavior standpoint, a separation of inductive RFID systems (f < 30 MHz)
and systems with electromagnetic wave propagation (f > 30 MHz) was hereby given. These
frequency ranges differ greatly in their physical properties.
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Differentiation of the Frequency Ranges
For passive Transponders
Frequencies < 30 MHz
UHF Frequencies
without Battery
(ISO 18000-2,3)
(ISO 18000-6; EPC)
Range:
Up to 0.8 m (single antenna)
Over 5 m (FCC)
Up to 1.4 m (gate antenna)
Up to approx. 4.0 m (ETS)
Homogeneous with definite
Inhomogeneous with
boundaries
overreach
Tag Antennas:
Inductive coils;
Dipole antennas;
Transponder Orientation:
different Orientations possible
polarization-dependent,
Transmission Field:
multiple antennas
Influence of Metal:
Influence of Liquids:
Direct attachment to metal not
Metal acts as a mirror,
possible; range reduction
reflections, overreach
Negligible
Absorbs power; range
reduction
Commissioning Work:
Low to medium, orientation-
Medium to high, environment-
dependent
dependent
To bring about a universal standardization, the ISO/IEC 18000 was developed and has largely
been adopted in the meantime.
Basically, the ISO/IEC 18000 deals with the definition of wireless transmission interfaces for the
identification of goods labels – stored in RFID transponders – by readers/writers, which relay this
identification information to IT systems or controllers. Here, item management not only includes
the handling of goods, but also the identification of packages and containers as well as the broad
area of materials flow control.
Part 1 of the ISO/IEC 18000 standard represents the general section with the definition of the
overriding parameters.
Part 2 describes two different communication types for transmission frequencies below 135 KHz.
These transmission frequencies have been actively utilized for identification purposes for years,
e.g. in access control, animal identification, etc.
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ISO/IEC 18000 – RFID Air Interface Standards for the Item Management
Part 1: General Section with principal Specifications
Part 2: Transmission Frequencies below 135 KHz
Tag type A: FDX 125 kHz
Tag type B: HDX 134,2 kHz
Part 3: Transmission Frequency 13.56 MHz
Mode 1: Based on ISO/IEC 15693
Mode 2: High Transmission Rate, 8 Data Channels
Part 4: Transmission Frequency 2.45 GHz
Mode 1: Passive Backscatter System
Mode 2: Active long-range System with high Transmission Rate
Part 5: Transmission Frequency 5.8 GHz (withdrawn)
Part 6: Transmission Frequency in the UHF Range (860 to 960 MHz)
Type A: Pulse interval encoding *1)
Type B: Bi-phase modulation & Manchester encoding *1)
Type C: EPC Class 1; Generation 2 ? *1)
*1) Different Anti-Collision Algorithms
Part 7: Transmission Frequency 433 MHz
Active Transponders, mainly for the Container Identification
Of particular interest for the goods identification is part 3 with the transmission frequency of 13.56
MHz. For this frequency, transponders can be manufactured very cost-effectively. Electromagnetic
interference is very low and ranges of approximately 80 cm can be reliably achieved. Moreover, a
standard for this frequency (ISO/IEC 15693) has been in existence for three years and – at least in
Europe – it is widely used. The number of product and system providers is also increasing
steadily. For this area, Siemens is offering the identification system MOBY D and can point to
numerous successful tests and applications. The 13.56 MHz frequency band is also approved for
use in North America and Japan. In the USA, the FCC requires slightly deviating limit values,
which are taken into account by the standard as well.
Part 4 of the ISO/IEC 18000 deals with a different setting – the ISM frequency band at 2.45 GHz
with a bandwidth of 82 MHz. Mode 1 describes a low-cost backscatter system with passive
transponders that functionally corresponds to the type B of the ISO/IEC 18000-6 in the UHF
range.
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MOBY U from Siemens corresponds to mode 2 and represents an RFID system in the upper
performance category for large data quantities and high transmission rates. To increase the range
and to ensure a reliable data transmission, active battery-powered transponders are employed
here.
Currently experiencing a lot of interest is the ISO/IEC 18000-6 in the UHF frequency range. Here,
the frequency band from 902 MHz to 928 MHz used in the USA is combined with a small
frequency window between 865 MHz and 869 MHz used in Europe. Although this requires
readers/writers with different frequencies, the transponders are readable and writable on both
sides of the Atlantic. Since the transponders are passive, their operating power has to be
extracted from the electromagnetic wave. In the USA, where a maximum radiation power of 4 W is
permitted, this functions over distances of several meters. In Europe, the approval guidelines
would have to be changed for this. The recently passed ETS 320 208 permits a maximum
radiation power of 2 W, making ranges of 3 m possible. Employing a gate antenna construction,
goods movements at loading doors and warehouse transition areas can now effortlessly be
detected automatically.
This is gaining importance, since the EPCglobal activities for creating an RFID alternative to the
bar code are based on these frequency bands. The EPCglobal initiative emerged from the AutoID
project and is being taken over and continued by the goods labeling organizations EAN and UCC.
Now this may give the impression that the standardization only led to a collection of various
proprietary systems. This would be incorrect, since the versatility of the different applications
require different physical properties and thus different technological solution concepts.
The standardization of the air interface – at least – forms the basis for many new RFID
applications, since it ensures that transponders from different manufacturers can be detected,
read and written to by different readers/writers. Beyond that, supplemental and further-reaching
standardizations already do exist.
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Further important RFID Standards for the Item Management
ISO/IEC 14443 – Proximity Smart Cards 13.56 MHZ
Electronic Ticket, closed Exchange
Goods Receipt/Issue Slip and Logistics
ISO/IEC 15693 – Vicinity Cards & Smart Labels 13.56 MHz
Part 1: Physical Properties
Part 2: Air Interface and Interface Signals
Part 3: Anti-Collision and Transmission Protocol
-> ISO 18000-3 Mode 1
ISO/IEC 15961, 15962 – Identification of Goods via RFID
User Interface (API), Data Protocol,
Functions and Data Encoding
ISO/IEC 15963 – Unique Manufacturer Identification
ISO/IEC 18047 – Conformity Test Methods (Technical Protocol)
ISO/IEC 18000-2,3,4,6,7
In addition, function interfaces in the ISO/IEC 15962/ 63 have also been defined on a logical level,
standardizing the data handling and the function syntax for IT systems. With this, the basis for a
uniform application interface is created.
An important standardization objective is the so-called interoperability. This means that
components from different manufacturers or providers can communicate and are compatible with
each other on the basis of the agreed standard. This is one of the basic requirements for open
process circuits. Supporting this will be the ISO/IEC 18047 (currently being worked on), which
describes test procedures for ensuring conformity with the ISO/IEC 18000.
Despite standardization, finding the right RFID system remains a challenging task. Important is a
thorough analysis of the processes and requirements. The sequencing of greatly varying
processes with different requirements has to be considered, e.g. the identification of goods
directly, materials in containers or multiple objects in one package – often fully automated on
conveyors or with portable handheld readers. In loading processes carried out by forklifts, long
ranges are often required and metal screens may be present, which put a general stop to an RFID
solution. Thus, besides the necessity for standardization, there are also numerous possibilities for
differentiation.
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Memory Size and Data Structure
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Security Functions, Access Rights
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Design and Mounting, Base Material
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Permissible Temperature Range
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Chemical Resistance
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Range and Tag Orientation
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Group Acquisition; Speed
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System Interfaces, IT Integration
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Interference Immunity and Degree of Protection
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Commissioning Support
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Acquisition Conditions
Illustration: Differentiation Possibilities
Competent partners with RFID know-how and a diligent configuration are important prerequisites
for a successful installation. The standardization taking place now offers a good basis for finding
the right system and knowing all alternatives, thus protecting the investments made in RFID for
the next few decades.
Abbreviations:
RFID =
UHF =
EPC =
EAN and UCC =
Radio Frequency Identification
Ultra High Frequency
Electronic Product Code
EAN International and Uniform Code Council; Standardization Organizations
for Goods Labeling
Author:
Siemens AG
Factory Automation Sensors
Gerd Elbinger
E-Mail: gerd.elbinger@siemens.com
www.siemens.com/simatic-sensors/rf
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