センサネットワーク
    Sensor Networks
    担当：山内規義教授
    Prof. Noriyoshi Yamauchi
    June 12, 2008
    センサネットワーク
    Sensor Networks
    担当：山内規義 教授
    Prof. Noriyoshi Yamauchi
    RFID
    Radio Frequency－Identification
    RFID
    Radio Frequency－Identification
    • RFID is a means of identifying a person or
    object using a radio frequency
    transmission.
    The technology can be used to identify,
    track, sort or detect a wide variety of
    objects.
    Communication takes place between a
    reader (interrogator) and a transponder
    (Silicon Chip connected to an antenna)
    often called a tag.
    • Tags can either be active (powered by
    battery) or passive (powered by the reader
    field), and come in various forms including
    Smart cards, Tags, Labels, watches and
    even embedded in mobile phones.
    The communication frequencies used
    depends to a large extent on the
    application.
    The various features of RFID systems
    • TransponderはTRANSmitter（送信機）と
    resPONDER（応答機）からの合成語で、受
    信した電気信号を中継送信したり、受信信号
    に何らかの応答を返す機器の総称
    RFID
    Example
    Security
    Immobilizer(Texas Instruments’ )
    Other
    Library
    Sushi
    Region MAP
    Available & Practical RFID Frequencies
    The frequency ranges used for RFID systems range from the
    myriametric range below 135kHz, through short wave and
    ultrashort wave to the microwave range, with the highest
    frequency being 24GHz. In the frequency range above
    135kHz the ISM bands available worldwide are preferred
    Typical RＦＩＤ System
    Structure of RFID
    ＲＦＩＤ System
    • In a typical system tags are attached to objects. Each
    tag has a certain amount of internal memory (EEPROM)
    in which it stores information about the object, such as
    its unique ID (serial) number, or in some cases more
    details including manufacture date and product
    composition. When these tags pass through a field
    generated by a reader, they transmit this information
    back to the reader, thereby identifying the object. Until
    recently the focus of RFID technology was mainly on
    tags and readers which were being used in systems
    where relatively low volumes of data are involved.
    ＲＦＩＤ
    • Every object to be identified in an RFID system will need
    to have a tag attached to it. Tags are manufactured in a
    wide variety of packaging formats designed for different
    applications and environments. The basic assembly
    process consists of first a substrate material (Paper,
    PVC, PET...), upon which an antenna made from one of
    many different conductive materials including Silver ink,
    Aluminum and copper is deposited. Next the Tag chip
    itself is connected to the antenna, using techniques such
    as wire bonding or flip chip. Finally a protective overlay
    made from materials such as PVC lamination, Epoxy
    Resin or Adhesive Paper, is optionally added to allow the
    tag to support some of the physical conditions found in
    many applications like abrasion, impact and corrosion.
    ＲＦＩＤ Packaging
    ＲＦＩＤ Packaging
    • In terms of computational power, RFID tags are quite
    dumb, containing only basic logic and state machines
    capable of decoding simple instructions. This does not
    mean that they are simple to design! In fact very real
    challenges exist such as, achieving very low power
    consumption, managing noisy RF signals and keeping
    within strict emission regulations. Other important circuits
    allow the chip to transfer power from the reader signal
    field, and convert it via a rectifier into a supply voltage.
    The chip clock is also normally extracted from the reader
    signal. Most RFID tags contain a certain amount of NVM
    (Non volatile Memory) like EEPROM in order to store
    data.
    ＲＦＩＤ Packaging
    How ＲＦＩＤ Tags Communicate
    • In order to receive energy and communicate with a reader, passive
    tags use one of the two following methods shown in fig 7. These are
    near field which employs inductive coupling of the tag to the
    magnetic field circulating around the reader antenna (like a
    transformer), and far field which uses similar techniques to radar
    (backscatter reflection) by coupling with the electric field. The near
    field is generally used by RFID systems operating in the LF and HF
    frequency bands, and the far field for longer read range UHF and
    microwave RFID systems. The theoretical boundary between the
    two fields depends on the frequency used, and is in fact directly
    proportional to l/2p where l = wavelength. This gives for example
    around 3.5 meters for an HF system and 5 cm for UHF , both of
    which are further reduced when other factors are taken into account.
    Energy and information transfer
    between reader and tag
    RFID Reader
    RFID Reader and Label Printer
    UID
    Unique item Identification
    • UID is the set of data for tangible assets
    that is globally unique and unambiguous,
    ensures data integrity and data quality
    throughout life, and supports multi-faceted
    business applications and users.
    • EPC (Electronic Product Code)
    • ONS (Object Name Service)
    EPC
    Electronic Product Code
    • In October 1999 the Auto-ID center was
    created in the Department of Mechanical
    Engineering by a number of leading figures at
    MIT . The potential benefits of RFID tags had
    been identified long before, what was stopping
    the adoption of the technology in the supply
    chain was the cost of the tags.
    ONS
    Object Name Service
    • ONS matches the EPC code to
    information about the product via a
    querying mechanism similar to the DNS
    (Domain Naming system) used in the
    internet, which is already proven
    technology capable of handling the
    volumes data expected in an EPC RFID
    system. The ONS server provides the IP
    address of a PML Server that stores
    information relevant to the EPC.
    Major Areas of RFID
    •
    •
    •
    •
    •
    Access Control
    Container Security
    Container Identification and Location
    Activity Tracking
    Regulatory Compliance
    Contactless Smart Cards
    Available standards for contactless smart cards
    Standards
    Card type
    Approximate range
    ISO / IEC 10536
    Close coupling
    0～2mm
    ISO / IEC 14443
    Proximity coupling
    0～10cm
    ISO / IEC 15963
    Vicinity coupling
    0～1m
    The various smart cards
    ID-1 card
    ISO 7810
    Smart cards
    ISO 7816
    Contactless
    smart cards
    CICC
    close cpl.
    ISO 10536
    Memory
    card
    contact
    Processor
    card
    Processor
    card
    PICC
    proximity
    ISO 14443
    Memory
    Card
    13.56 MHz
    contactless
    VICC
    vicinity cpl.
    ISO 15693
    Processor
    Card
    13.56 MHz
    RICC
    remote cpl.
    ISO ???
    Memory
    Card
    13.56 MHz
    Memory Card (battery)
    2.4 / 5.8 GHz
    Dual interface card
    Family of (contactless and contact) smart cards,
    with the applicable standards
    Structure of Contactless Smart Cards
    Suica
    Suica
    •
    ICテレホンカードとSuica
    •
    非接触ICカードの開発は、1980年代から始められましたが、日本での本格的な普及が始
    まったのは、つい最近で、1999年に運用が開始されたNTTのICテレホンカードが日本にお
    ける実用化第1号です。
    ちなみに、ICテレホンカードは、利用者が増えないことなどから、2006年3月末でサービス
    が終了しました。一方、2001年にサービスを開始した、JR東日本の非接触ICカードを利用
    したプリペイド乗車券であるSuicaは、着実に利用者を増やし、サービス開始から3年とかか
    らずに、1,000万枚を発行しました。
    Suicaは、乗車券としてだけなく、電子マネーとしても用途を広げ、利用可能な場所は、駅の
    中から、駅の外へと着実に広がっています。Suicaの爆発的ともいえる普及により、非接触
    ICカードは、注目を浴び始めました。JR東日本のSuicaに続き、JR関西のICOCA、スルッと
    KANSAIのPiTaPa、JR東海のTOICAといった交通系の非接触ICカードの運用が開始され
    たほか、2007年3月18日には、首都圏の私鉄やバスなどで利用できるPASMOの運用も始
    まります。
    FeliCaは、のちに携帯電話などに内蔵できるように設計された「モバイルFeliCa」というバリ
    エーションも登場し、すでに、携帯電話にとって必須の機能と言っても過言でないでしょう。
    ちなみに、FeliCaのコアとなるICチップで数えると（FeliCaとモバイルFeliCaの合計に相当）、
    2005年10月の時点で、1億個を出荷したことが発表されました（※FeliCaやモバイルFeliCa
    と、これらを使用している各種のサービスについては、次回、詳しく触れます）。
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