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Introduction to RFIDs and Sensor Networks. prepared by Prof. Yeonghwan Tscha. CONTENTS. RFIDs and Their Technologies USN Sensor Nodes and Their Technologies Communications Technologies Security Issues Application Examples. What is RFID ?.
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Introduction to RFIDs and Sensor Networks prepared by Prof. Yeonghwan Tscha
CONTENTS • RFIDs and Their Technologies • USN Sensor Nodes and Their Technologies • Communications Technologies • Security Issues • Application Examples
What is RFID ? • Stands for Radio Frequency Identification • Uses radio waves to provide unique identification (i.e. serial number) plus data • Is one form of automatic identification Antenna Tags Reader
RFID Overall Operations Tag Reader Host Computer
What the Reader gets from Tags EPC(Electronic Product Code)
How do they look like? www.datasoft.se www.eff.org Readers Printer and Smart Label (barcode + tag) www.barcoding.com www.kennedygrp.com Tags www.smartcodecorp.com glossary.ippaper.com
Tag RFIDs in Our Living Spaces
RFID System • The tag consists of antenna and a microchip • The reader consist of a transmitter, receiver, and one or more antennas • (if any) The printer is a type of stationary reader which prints smart label that consists of a barcode and a RFID tag • The backend computer system called Savant server • Communication protocols • Interfaces to the computer networks like the Internet • The special system software called Middleware
RFID System, Outlook (Savant Server)
Networked RFIDs Antenna Tag RF Channel Savant Server Reader Internet PML (Physical Markup Language) Server ONS(Object Name Service) Server
RFID Tag • RFID Tag is a device used to transmit information such as a serial number to the reader in a contactless manner • The tag has a typically up to 4K bytes memory in size(recently, 128K bytes tag is available) • Classified as • Passive • Active • Semi-passive(semi-active) • Also called transponder
RFID Readers • The reader is known as interrogator which can read and write data to the RFID tags • The reader powers the tag by sending it RF energy • The reader consists of • transceiver(transmitter/receiver), antenna • microprocessor, memory, controller(firmware) • communications interfaces • power supply
RFID Printers • Readers are classified as stationary or handheld • The RFID printers is a type of stationary reader which print smart label that consists of a barcode and a RFID tag • Information such as sender id, receiver id, product information, etc can be printed
Tag-Reader Coupling • Inductive Coupling(유도결합) • Backscatter Coupling(후방산란 결합)
Security Issues in RFID “Kill” Command
Security Issues in RFID Active Jamming
Security Issues in RFID The Faraday Case Radio Shielding Antenna Reader Tags Metal Network or Foil
Blocker Tag(RSA) Only the tag labeled with the blocker securely communicates with the reader
Collision Issues in RFID Intra-reader Collision Antenna Reader Tags
Collision and Radio Interference Between Readers Inter-reader Collision and Radio Interference Antenna Antenna Reader Reader Tags
Anti-Collision Methods in RFID Deterministic(Tree) Memoryless Memory Bit Arbitration Splitting Tree Tree Walking Query Tree Probabilistic(S-ALOHA) Bit-Slot ID-Slot I-Code STAC(Slotted Terminating Adaptive Collection)
Anti-Interference Methods in RFID FH SDMA FDMS Beacon TDMA CSMA Reader Interference Multi Reader-Tag Interference Plus & Minus Simple Fixed Reader Only H/W complex, Channel Policy Beacon needed, Capacity Limited Inter-reader Synchroni-zation needed simple Standards Non 100% prevention Deployment issue Gen2 Spec. Idea level Gen2 Spec. ETSI
RFID System관련 국내업체(일부) • 한세텔레콤http://www.hansetel.com • ㈜ 키스컴http://www.kiscom.co.kr • 아이윌소프트㈜http://www.iwillsoft.net • 유컴테크놀러지http://www.ucommtech.com • ㈜유비홀딩스http://ubiu.com • 한맥ENG www.hmtrade.co.kr • (주)화성아이앤티http://www.hsint.co.kr • 고려시스템http://www.barcode.ne.kr • ㈜엔트너http://www.ntner.co.kr • 씨에스테크놀러지http://msi.cst21.com • 한국바코드http://www.kbarcode.com
RFID 응용(IITA) 자동차 번호판 인식
RFID for USN(Ubiquitous Sensor Networks), Sensor Node USN Sensor Node WLAN/ Internet Middleware Reader All-In-One Tag Sensor
USN Sensor Node Example Mobile Phone + RFID Mobile RFID
Sensor Node Function Block SPI: Serial Parallel Interface MAC: Medium Access Control MCU: Microprocessor Control Unit NWK: Network
Why “Zigbee” ? Bees flying in the Zig-Zag style !!!
6LoWPAN IPv6 over Low power WPAN(Wireless Personal Area Network-IEEE802.15.4/Zigbee)
IEEE 802.15.4 Physical Layer * All use the DSSS(Direct Sequence Spread Spectrum) access mode
Multiple Access Single Medium Shared by Multiple Users: only one can send successfully at a time
TDMA • Time-Division Multiple Access • Access to channel in "rounds" • Each node gets fixed length slot (length = frame tx. time) in each round • A frame consists of slots from each node • Unused slots go idle • Example: 6-node LAN, 1,3,4 have frames, slots 2,5,6 idle Slot(time slice) Frame
FDMA • Frequency-Division Multiple Access • Channel spectrum divided into frequency bands • Each node assigned fixed frequency band • Unused tx time in frequency bands go idle • Example: 6-node LAN, 1,3,4 have frames, slots 2,5,6 idle time 1 2 3 frequency bands 4 5 6
CDMA • Code-Division Multiple Access • Every channel uses the entire spectrum • Also called as spread spectrum • Unique code(referred to as chipping sequence) assigned to each user; i.e., code set partitioning • allows multiple users to “coexist” and transmit simultaneously with minimal interference (if codes are orthogonal) • FHSS: Frequency Hopping Spread Spectrum • DSSS: Direct Sequence Spread Spectrum