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RCEAT for Radio Frequency Identification (RFID)UHF Tag By K.KARTHIK A.SWAPNA

A.DEEPTHI

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Stands for Radio Frequency Identification Uses radio waves for identification New frontier in the field of information technology One form of Automatic Identification Provides unique identification or serial number of an object

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Local ServerTag ID

Reader Tag ID

Tags

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Automatic identification procedures (Auto-ID) have become very popular in many service industries, purchasing and distribution logistics, industry, manufacturingcompanies and material flow systems. Automatic identification procedures exist to provide information about people, animals, goods and products in transit.

Fig: Overview of most important Automatic ID procedures

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Introduction (contd..)Table: Comparison of different auto-ID systemsSystem parameters Barcode OCR Voice recognition High Simple Very high Biometry Smart card 1664 k Very high Impossible Low RFID systems 1664 k Very high ImpossibleMedium

Typical data quantity (bytes) Data density Readability by people Purchase cost/reading electronics Unauthorized copying/modification Reading speed (including handling of data carrier)

1100 Low Limited Very low

1100 Low Simple Medium

High Difficult Very high

Slight

Slight

Possible (audio tape) Very low >5 s

Impossible

Impossible

Impossible

Low ~4 s

Low ~3 s

Very low >510 s

Low ~4 s

Very fast ~0.5 s

Maximum distance between data carrier and reader

050 cm

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1935

1960

1973

Whats next?1999

2006

2004

19996

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TAG RF circuit & analog circuit

Baseband processor

READER

EEPROM

Fig: RFID System components

Reader consists of A radio frequency module (transmitter and receiver) A controlunit which controls the flow of data A coupling element like an antenna to thetransponder Tag consists of Microchip for storage and computation coupling element, such as an antenna coil for communication RFID systems operate according toone of two basic procedures: Full duplex (FDX) or half duplex (HDX) systems Sequential (SEQ) systems

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Passive Operational power scavenged from reader radiated power

Semi-passive Operational power provided by battery

Active Operational power provided by battery - transmitter built into tag

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Inductive Coupling

Backscatter

Reader

TAG

Reader

N

TAG

S

Near field (LF, HF): inductive coupling of tag to magnetic field circulating around antenna (like a transformer) Varying magnetic flux induces current in tag. M

odulate tag load to communicate with reader field energy decreases proportionally to 1/R3 (to first order) Far field (UHF, microwave): backscatter. Modulate back scatter by changing antenna impedance Field energy decreases proportionally to1/R Boundary between near and far field: R = wavelength/2 pi so, once have reached far field, lower frequencies will have lost significantly more energy than high frequencies Absorption by non-conductive materials significant problem for microwave frequencies

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Also known an interrogator Reader powers the tag by sending it RF energy Can behandheld or stationary Consists of: Transmitter Receiver Antenna Microprocessor Memory Controller or Firmwaication channels Power

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Need for RFIDTransportation payments People tagging Auto-immobilizer Supply Chain

Traffic TollFrequency LF HF UHF wave 125khz 13.56Mhz 900Mhz 2.4Ghz Distance Few cm 1m ~7m 10m

Example ApplicationAutoImmobilizer Building Access Supply Chain Traffic Toll

Focus is on UHF

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Number of bits Collision Avoidance Reader Power Frequency Type of tag Tag classification Read range Coupling

96 or 128/256 bits Slotted ALOHA Below 1W 902~920MHz(ISM band (unlicensed)) Passive Class 1-Read, write once / write many (Generation 2) 2-7 meters Electromagnetic

Operating procedureStandard Implementation

Half Duplex modeMeets EPC Global Gen2 (v.1.0.9) and ISO/IEC 18000-6c Designed for high performance and low power consumption based RFID for 130nm silicon process

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TAG

Functional block diagram

RF circuit & analog circuit

Baseband processor

EEPROM

SpecificationsDemodulated signal from the reader Serial Data Line Parallel Data Line Control Line w.r.t data

Receive Buffer

Comparator Operating Procedure No of bits Half Duplex 96-bit Electronic productcode (64 bit ID; 16bit CRC; 8 bit Pass; 8 bit Control Slotted Aloha [RNG & SlotCounter] OOK (On Off Shift Keying) [ASK] Receiver:100khz; Transmitter:12.5Mhz; Comparator, RNG, Slot Counter, CRC, Memory,: 200khz

Reset Counter

Controller

Memory Controller Collision Avoidance

Modulated signal to the reader

Transmit buffer

Modulation type Slot counter RNG Operating frequency

AdvantagesLow power consumption and reduced complexity

Due to good security feature, no complicated coding or cryptography is needed.

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Power Up

Receive Buffer Receives the data/command from the reader. [ID-64bits, CRC-16bits, Pass8bits]

If received bit count is not correct

If received bit count is correct

Controller Sends the control signals to the subblocks. It starts the module whenever needed and stops when the task is completed

Compare Compares the received ID and the ID stored in the memory.

No

YesStores the verified data in the latch and generates the 16 bit CRC for transmission of this data.

Random number generator

Slot Counter

Transmit Buffer Transmits the modulated data/command to the reader. [ID64bits, CRC-16bits, Pass-8bits]

Anti-collision

Reset/Halt

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Conveyor Belt

Dock Door

Forklift Printers

Handheld

Smart ShelvesPoint of Sale

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Time

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The reference architecture was modified by modifying the controller block In reference architecture, the controller was controlling only the data flow to each of the sub modules, whereas the modified architectures controller controls both clock and the data flow for each of the sub module

Demodulated signal from the reader

Receive Buffer

Comparator

Serial Data Line

Parallel Data Line

Reset Counter

Controller

Memory Controller

Control Line w.r.t clock and data

Modulated signal to the reader

Transmit buffer Slot counter RNG

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Test SetupTest Select

Test Data Unit Test Case 1 Test Case 2

Simulation window

Clock

Reset

Baseband Processor

Serial Input data

Modulate d Serial bits

Clock :100 MHz Reset :Active high Input bits: 88 bits serial Output : 88 bits serial which is amplitude modulated Given test case: 11001111000000010000000100000001000000010000000100000001000000010000000 1111111111111111 Expected Output:011001111000000010000000100000001000000010000000100000001000000010000000 101111100010110

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ConclusionA proposed reliable and cost effective anti-collision technique (RCEAT) is designed to achieve a reliable and cost effective identification technique of the tag.The RCEAT architecture consists of two main sub systems: pre RCEAT checks errorsin the incoming packets using the crc scheme. post RCEAT identifies the error free packets using binary tree based technique. Architecture has been synthesizedusing Xilinx synthesis Technology (XST), simulated using MODELSIM.

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QUERIES?

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