Applying Passive RFID System to Wireless Headphones for Extreme Low Power Consumption

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Applying Passive RFID System to Wireless
Headphonesfor Extreme Low Power Consumption

• June 11th, 2008
• Joon Goo Lee, Dongha Jung, Jiho Chu, Seok Joong
  Hwang, Jong-Kook Kim, Seon Wook Kim
• School of Electrical Engineering, Korea
  University, Seoul, Korea
• Janam Ku
• Samsung Advanced Institute of Technology, Korea

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Content

• RFID
• Research Motivation
• Design Possibility and Opportunity
• Extended Gen2
• Features of the original Gen2 (ISO18000-6 Type C)
• Added new commands for massive transferring to
  tags
• Modified command and response Write
• Added new state and State transition of the EGen2
• EGen2 Prototype System
• Overall verification system
• EGen2 Sender System
• EGen2 Receiver System
• Performance Evaluation
• Conclusion

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Content

• RFID
• Research Motivation
• Design Possibility and Opportunity
• Extended Gen2
• Features of the original Gen2 (ISO18000-6 Type C)
• Added new commands for massive transferring to
  tags
• Modified command and response Write
• Added new state and State transition of the EGen2
• EGen2 Prototype System
• Overall verification system
• EGen2 Sender System
• EGen2 Receiver System
• Performance Evaluation
• Conclusion

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RFID Radio Frequency IDentification

• Identify objects from a distance by using a small
  IC with RF transponder
• RFID system is made up of three components
• Transponder or tag, Interrogator or Reader, and
  Application
• Classification
• SAW/Inductive/Modulated Backscatter/Active
• Read Only/WORM/Reprogrammable/Read and Write
• 125-135kHz/13.56MHz/UHF(300-1000MHz)/2.45GHz
• Inductive/Electromagnetic (Narrowband, Spread
  Spectrum)

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General Use of RFID Technology

• Inventory control
• Container/Pallet Tracking
• Access control
• Equipment/Personal Tracking (In hospital, prison,
  etc.)
• Product tracking through manufacturing,
  assembly,and supply chain
• Fleet maintenance
• Various services by using mobile RFID
• Most applications are related to logistics and
  security.

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Content

• RFID
• Research Motivation
• Design Possibility and Opportunity
• Extended Gen2
• Features of the original Gen2 (ISO18000-6 Type C)
• Added new commands for massive transferring to
  tags
• Modified command and response Write
• Added new state and State transition of the EGen2
• EGen2 Prototype System
• Overall verification system
• EGen2 Sender System
• EGen2 Receiver System
• Performance Evaluation
• Conclusion

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Motivation (1/2)

• When we use wireless communication device
• Power consumption limits its usage!!!

What is the wireless communication method which
consumeslowest power?
The answer is Passive RFID!!
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Motivation (2/2)

• A kind of energy harvesting technology is used in
  passive RFID system
• However, RFID system has been only applied for
  automatic data acquisition methods
• Because of relatively lower data rate, security
  problem,range of communication, power
  dissipation of memoryread/write, and so on
• What if a passive tag just bypasses the received
  data to other device, is it possible to use
  passive RFID technology for special purposes?
• Data transmission system without storing the data
• For an example, a headphone

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Content

• RFID
• Research Motivation
• Design Possibility and Opportunity
• Extended Gen2
• Features of the original Gen2 (ISO18000-6 Type C)
• Added new commands for massive transferring to
  tags
• Modified command and response Write
• Added new state and State transition of the EGen2
• EGen2 Prototype System
• Overall verification system
• EGen2 Sender System
• EGen2 Receiver System
• Performance Evaluation
• Conclusion

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Design Possibility and Opportunity (1/2)

• What kind of passive RFID protocol is sufficient?
• We need
• High data rate NFC, ISO18000-6 Type C (Gen2)
• Long working range ISO18000-6 series, ISO18000-3
• Small size of device ISO18000-6 series,
  ISO18000-3
• ISO18000-6 Type C is the best for the first step
• Feasibility checking with Gen2
• Friss transmission equation was used for the
  calculation of path loss
• Assumptions
• Reader transmits 10dBm power to tags
• Antenna gain of the reader is 6dBi and antenna
  gain of a tag is zero
• Efficiency of a tag rectenna is 80
• Half of the rectified power is available to the
  digital parts of a tag

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Design Possibility and Opportunity (2/2)

• The result of channel modeling for the passive
  RFID of 860960MHz band from Friss equation and
  our assumptions

• From the above result, voice data and low quality
  music transmission is enough with Gen2

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Content

• RFID
• Research Motivation
• Design Possibility and Opportunity
• Extended Gen2
• Features of the original Gen2 (ISO18000-6 Type C)
• Added new commands for massive transferring to
  tags
• Modified command and response Write
• Added new state and State transition of the EGen2
• EGen2 Prototype System
• Overall verification system
• EGen2 Sender System
• EGen2 Receiver System
• Performance Evaluation
• Conclusion

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Extended Gen2 (1/4)

• Features of the original Gen2
• Uses UHF (860960MHz) band, backscatter
  modulation
• Forward modulation DSB-ASK, SSB-ASK or PR-ASK
• Backward modulation ASK and/or PSK
• Data encoding PIE for R2T, FM0 or Miller for T2R
• Operating range Several meters (Depends on
  Readers Tx power)
• Tag size Sufficiently small (It depends on
  antenna design)
• Data link frequency Relatively high
• Forward 26.7kHz128kHz
• Backward 40kHz640kHz
• Supports multi-reader environment ? Session
  concept
• Has 4 kinds of memory banks (One of them is EPC
  code)
• Error detect CRC5 or CRC16

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Extended Gen2 (2/4)

• Added new commands for massive transferring to
  tags
• Burst command format and description
• BurstAckVS command format and description and its
  response format

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Extended Gen2 (3/4)

• Modified command and response Write

• Write command was modified for writing ShortID in
  temporal memory
• After Select operation, issue Write command in
  Ready state
• After setting Membank, WordPtr, and RN as zero,
  assign ShortID reader wants with lower 7bit of
  Data
• After writing ShortID to temporal memory of Tag,
  the Tag responds CRC check result of Write
  command and written ShortID
• There is no TREPLY (about 20ms) ? Reduce the
  power consumptionof the Reader
• Automatic ShortID initialization when tag is out
  of reading zone

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Extended Gen2 (4/4)

• Added new state
• Data
• The state transition diagram of the EGen2 tag
• Fully compatible with original Gen2

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Extended Gen2 (appendix)

• Supported communication methods and their
  procedure with EGen2 protocol
• 1. Broadcast
• Send Burst command with ShortID0000000b
• All tags in the reading zone process the Burst
  and BurstAckVS commands
• When retransmission is unnecessary, reader omits
  setting ShortID
• 2. Multicast
• Procedure
• i) Inventory (Recognizing Tag ID)
• ii) Assert SL flag of wanting tag
• iii) Assign a unique ShortID to the tag
• iv) Choose wanting tags by repeating ii)iii)
• Send Burst command with ShortID!0000000b ? SL
  asserted tags process Burst and BurstAckVS
• 3. P2P
• Procedure
• i), ii), iii) are same as Multicast procedure
• iv) Send Burst command with ShortIDthe unique
  ShortID ? The tag which has the unique ShortID
  processes Burst and BurstAckVS

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Content

• RFID
• Research Motivation
• Design Possibility and Opportunity
• Extended Gen2
• Features of the original Gen2 (ISO18000-6 Type C)
• Added new commands for massive transferring to
  tags
• Modified command and response Write
• Added new state and State transition of the EGen2
• EGen2 Prototype System
• Overall verification system
• EGen2 Sender System
• EGen2 Receiver System
• Performance Evaluation
• Conclusion

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EGen2 Prototype System (1/5)

• Overall verification system
• Sender was modified from an original Gen2 tag
  reader
• EGen2 tag in receiver was extended from an
  original Gen2 tag
• Audio signal sampling rate was 14kHz and
  resolution of eachsample was 8-bit

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EGen2 Prototype System (2/5)

• EGen2 Sender System

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EGen2 Prototype System (3/5)

• EGen2 Receiver System (1/3)

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EGen2 Prototype System (4/5)

• EGen2 Receiver System (2/3)
• EGen2 Tag architecture

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EGen2 Prototype System (5/5)

• EGen2 Receiver System (3/3)
• Hardware Scheduler for low power
• Minimizing power consumption of receiver system
  by changingthe CPUs power mode
• After AVR finishing the system initialization job
  as a general processor, the AVR changes its power
  mode to Power-down Mode orPower-save mode
• H/W Scheduler wakes up AVR by using external
  interrupt andresumes a job with the AVR

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Content

• RFID
• Research Motivation
• Design Possibility and Opportunity
• Extended Gen2
• Features of the original Gen2 (ISO18000-6 Type C)
• Added new commands for massive transferring to
  tags
• Modified command and response Write
• Added new state and State transition of the EGen2
• EGen2 Prototype System
• Overall verification system
• EGen2 Sender System
• EGen2 Receiver System
• Performance Evaluation
• Conclusion

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Performance Evaluation (1/2)

• Measurement Setup
• We didnt analyze the sender
• Gate level simulator was used for EGen2 tag and
  tag peripheral system
• Synopsys Design Compiler and Synopsys VCS under
  Anam CMOS 0.18um technology
• We used Prime Compiler with 25 toggle rate for
  the EGen2 tag power estimation
• The number of gates and the power consumption of
  tag components except for EEPROM
• Gate increase 3.5
• Power increase 3.8
• Available distance 1.8m

It is acceptable because EGen2 tag just
bypasses the received data to tag peripheral
system without writing the data into EEPROM
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Performance Evaluation (2/2)

• Tag peripheral system
• Consists of AVR, DAC, hardware system which
  includes DAC FIFO, two wrappers and a
  communication unit
• The DAC FIFO consists of 8-bit 256 entries 12K
  gates
• The rest of the hardware system 5K gates
• The power consumption of the hardware system was
  44uW
• When wake-up duty of AVR processor was 1 (1
  active, 99 power save), 614uW was consumed

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Content

• RFID
• Research Motivation
• Design Possibility and Opportunity
• Extended Gen2
• Features of the original Gen2 (ISO18000-6 Type C)
• Added new commands for massive transferring to
  tags
• Modified command and response Write
• Added new state and State transition of the EGen2
• EGen2 Prototype System
• Overall verification system
• EGen2 Sender System
• EGen2 Receiver System
• Performance Evaluation
• Conclusion

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Conclusion

• Contribution
• EGen2 protocol
• EGen2 is a ultra low power wireless communication
  protocol which is based on passive RFID
  technology
• Feasibility of new use of passive RFID systems
  with EGen2 protocol
• Digital parts of EGen2 tag consume 3.33 ? (25
  toggle rate) when the tag receives audio data
  from a sender
• Prototype system by adding new hardware modules
  to the Gen2 reader and tag for our proposal
• Proposal of a hardware control interface, an
  inter-IP communication unit, and a hardware IP
  scheduler in order to achieve the low power
  consumption of whole receiver system

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QA