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TINA showcase: Passive RFID


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This video forms part of the showcase event held by the Intelligent Airport (TINA) project:

The University of Cambridge Engineering Department developed a passenger tracking system using cheap passive RFID boarding passes.

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TINA showcase: Passive RFID

  1. 1. Multiservice RF Infrastructure with Passive Tag Location Capability<br />Richard Penty, S Sabesan, Michael Crisp, Ian White<br />Cambridge University Engineering Department<br />
  2. 2. In-Building Coverage/Distributed Antenna System<br /><ul><li>Unreliable coverage from outdoor cells
  3. 3. Dedicated indoor capacity
  4. 4. Fewer RF transceivers needed compared to distributed radios
  5. 5. Analogue links may be coax cable (<100 m) or fibre (>100 m)
  6. 6. Wideband versions can carry all required baseband and radio services</li></li></ul><li>3 Antennas<br />Distributed Antenna Network Performance<br />
  7. 7. Adding Sensing to Communications DAS<br />Passive UHF RFID allows very low cost tags to be used for object detection at ranges up to 10 m<br />Increasing demands for mobile data bandwidth is driving down cell sizes, requiring closer antenna spacing.<br />Can RFID be added as an additional service on RoF DAS allowing a shared infrastructure?<br />Can RFID leverage similar power requirement reductions to we have shown with communications services?<br />
  8. 8. Why RFID over Fibre in Airports?<br />RFID is considered cheaper than bar code readers<br />But <100% read rate reliability means critical reading for e.g. baggage is compromised<br />Only two airports internationally implement RFID for baggage handling<br />Within TINA we’ve tried to improve read success rate over a wider area<br />Airport applications, particularly if security sensitive, really do need ~ 100% success rate<br />Will allow tagging of other items e.g. passengers<br />Late passengers contribute to 10% of all delays in UK<br />Extremely expensive for airline business models<br />Different airlines would use passenger location information in different ways!<br />Security<br />Tagging of passenger, along with video, would reveal suspicious behaviour<br />Monitoring of security areas<br />
  9. 9. AU1<br />AU3<br />AU2<br />Improved Tag Detection with DAS<br />AU1<br />Rx<br />Tx<br />Zinwave Hub<br />RFID Tx<br />DAS Processing<br />RFID Rx <br />Tx<br />Rx<br />AU1<br />Tag<br />Tag<br />Aim to show improvement in RFID read rate/accuracy and reduction in nulls<br />AU1<br />Rx<br />Tx<br />
  10. 10. Demonstration of Error Free Operation Usinga Commercial RFID System<br />19 x 2 m area. +31 dBm EIRP output power, UK frequency band<br />
  11. 11. Improving Read Rate and Accuracy - Intel R1000<br />PC<br />Command-Begin Packet<br />DAS Settings<br />Antenna-Begin Packet<br />Inventory-Cycle-Begin Packet<br />ARM7<br />Micro controller<br />Inventory-Round-Begin Packet<br />Serial Interface<br />Inventory-Response Packet<br />DAS Settings<br />Inventory-Round-End Packet<br />Inventory-Cycle-End Packet<br />Intel R1000<br />Antenna-End Packet<br />USB Interface<br />Command-End Packet<br />Intel R1000 Firmware<br />Intel Transceiver Interface<br />(executing on PC)<br />(executing on ARM7)<br /><ul><li>Intel R1000 supports host side applications (Intel Transceiver interface). The transceiver interface includes a C/C++ functional interface to talk to the firmware module using USB communication.
  12. 12. When an inventory is performed using the transceiver interface, it returns data from the Intel firmware in a sequential of packets.
  13. 13. Phase is varied when it returns the inventory-round-begin packet which indicates the beginning of a an inventory round on an antenna. </li></ul>SSB Interface<br />Intel Transceiver R1000<br />
  14. 14. AU3<br />Rx<br />Tx<br />Zinwave Hub<br />Intel R1000 Firmware<br />DAS Processing<br />Intel R1000<br />Rx<br />AU2<br />Intel Transceiver R1000<br />AU1<br />AU3<br />AU2<br />Alien Tag<br />Tag<br />Alien Tag<br />Tag<br />Alien Tag<br />Tag<br />Alien Tag<br />Tag<br />Alien Tag<br />Tag<br />AU1<br />Rx<br />Tx<br />DAS RFID System<br />Tx<br />
  15. 15. Enhanced Read Rate/Accuracyusing R1000 Reader System<br />AU3<br />AU2<br />AU1<br /><ul><li>The conventional RFID system takes 1.7s to read 62 tags out of 80 (77.5% accuracy) </li></ul> - read rate of 36 tags/sec. <br /><ul><li>The R1000 system takes 1.2s to read all tags (100% accuracy),</li></ul> - read rate of 67 tags/sec<br />80 Alien Higgs2 tags are placed at a height of 2 m in a 50 cm grid interval over a 10 m x 4 m area. <br />
  16. 16. Providing Location in optical DAS RFID system<br /><ul><li>Now we can read a tag (quickly) over a large area, we have lost the location accuracy of an RFID “portal” – can we somehow improve the accuracy
  17. 17. Estimating the location of passive UHF RFID tag is a major challenge due to the narrow bandwidth available.
  18. 18. The most common techniques are based on RSSI location algorithms. </li></ul>- However, multi-path effects, fading and nulls result in the RSSI being only a weak function of range.<br /><ul><li>By using an optical DAS with multiple antennas, we can reduce the degree of fading in the field of view</li></ul>- and thus significantly improve the accuracy of RSSI location techniques.<br />
  19. 19. Passive UHF RFID RTLS<br />Location Algorithm<br /><ul><li>The area is first mapped by recording the combined RSSI from all the AUs and the RSSI of each AU
  20. 20. Measurements are repeated five times at each grid point and the AU with the highest number of successful reads is identified.
  21. 21. Location is then estimated by finding the closest match of:
  22. 22. the three antenna RSSI
  23. 23. the RSSI from the mostly likely closest antenna
  24. 24. the probability that the antenna is closest to the tag from the mapped data set.
  25. 25. A maximum likelihood weighting is applied to the mapped data.</li></ul> Pillar<br />
  26. 26. Demonstration of Enhanced Location Accuracy<br />
  27. 27. Demonstration of Enhanced Location Accuracy<br />100% location estimations using the DAS has less than 4.2 m error compared to only 55% and 40% from the commercial RFID reader and the random algorithm respectively. <br />
  28. 28. Tracking/Location System GUI<br /> We intend to use the current system as a test bed to develop new algorithms.<br />
  29. 29. Application Software Integration with Hong Kong-TINA Project<br />MySQL<br />Database<br />HK-TINA<br />Software<br />Intel R1000<br />Cambridge<br />Software<br />
  30. 30. Demonstrator<br /> Passive RFID over DAS demonstrator exhibiting<br /><ul><li>Large passive RFID field of view
  31. 31. 100% read accuracy using DAS to reduce fading
  32. 32. Enhanced read rate (67 tags/second)
  33. 33. RSSI based location with 1.9 m mean error
  34. 34. Integration with HK TINA software demonstrators</li>