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Wireless Communication for Wildlife Research

ECE 445 Final Presentation Spring 2005 Prof. Scott Carney. Christos Bais Mike Cristiano Tim Eggerding TA: Shenghui Zhang. Wireless Communication for Wildlife Research. Introduction. Project in conjunction with Illinois Natural History Survey

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Wireless Communication for Wildlife Research

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  1. ECE 445 Final Presentation Spring 2005 Prof. Scott Carney Christos Bais Mike Cristiano Tim Eggerding TA: Shenghui Zhang Wireless Communication for Wildlife Research

  2. Introduction • Project in conjunction with Illinois Natural History Survey • Wildlife radio tracking using remote Yagi antenna arrays • Remote stations log data, transmit to central station • Current communications via wired LAN

  3. Design Criteria • Economize power • Operate in rain, cold • 3-5 km data transmission above audio rate (256 Kbps) • Allow ‘ad-hoc’ mode to increase range • Low maintenance, high reliability • Comply with FCC regulations

  4. Protocol Design • OSI protocol stack • Design layers 1-4 • Allow for ‘ad-hoc’ mode • Data rate above quality audio (256 Kbps)

  5. Design Approaches • Construct transceiver hardware, write protocol • Use stock radio modem • Bluetooth for hardware and protocol standard • Use existing protocols for layers 2-4 • TCP/IP, UDP

  6. Solutions • Transceiver design, protocol writing too involved, not robust • Bluetooth chips difficult to program, build • Radio modems not fast enough (<200 Kbps) • Need to integrate existing protocol with stock transceivers

  7. Lantronix Wiport • Fully integrated 802.11b transceiver, TCP/IP stack • Ad-hoc network rates up to 11 Mbps • Requires 250mA @ 3.3V • Operates at -40 – 70 C • Serial RS-232, RS-485 interface • Serial, telnet, or Web configurable • $119

  8. Integration • Lantronix supplies evaluation board • Cheaper, more flexible design needed for production • Power, status LED’s, serial interface • Serial communication driven by MAX3223, male and female 9-pin DSUB for each serial port • Optional Ethernet interface

  9. PCB Design

  10. Antenna Design Overview: Basic Antenna Yagi-Uda Principles Friis Equation Simulations Yagi-Construction Testing/Comparison

  11. Basic Antenna

  12. Yagi-Uda Principles

  13. Friis Equations • PL = (2 qr Gr |pr*pt|2 Gt qt Ps)/(4r)2 • PL = Receive Sensitivity •  = c / 2.448 GHz = 12.2464 cm • qr,t = mis-match, r =receive, t=transmit • Gr,t = Antenna Gain • Ps = power available from source • r = distance in meters • |pr*pt|2 = Polarization match

  14. Friis Equation…cont. • Wi-Port Sensitivity: Sensitivity Theoretical Range 6dB buffer • -82dBm for 11Mbps • -87dBm for 5.5Mbps • -89dBm for 2 Mbps • -92dBm for 1 Mbps

  15. Simulations Using Nec

  16. Final Design

  17. Yagi Construction

  18. Testing/Comparison

  19. Antenna Wi-Port Interface • Balun • Connects a balanced device to an unbalanced device • Matching Network • Allows for maximum transfer of power from transceiver to antenna • Transmit power of Wi-Port 14dBm (25mW)

  20. Balun Construction • Link from antenna (balanced) to coaxial cable (unbalanced) • Implemented folded balun • Balances current with quarter wave length coaxial cable

  21. Impedance Matching Network • Match impedances between load (antenna and source output (PCB) 50 ohms • Designed using transmission lines • Frequency 2.4 GHz • Rated lumped elements are difficult to find

  22. Measuring Antenna Impedance • Performed measurements of the Network Analyzer • Recorded impedances at start, stop and center frequencies • Checked the return loss of the antenna

  23. Definitions • Smith Chart – Shows how close impedance match is to 50 ohms • Return Loss - Amount of Power reflected • -3dB 50% power transfer • -6dB 75% • -10dB 90% • -15dB 97%

  24. Antenna Results Return Loss Smith Chart

  25. Design and Simulation • Created several matching networks and simulated in Puff • Simulations showed design requirements fulfilled

  26. Different Designs

  27. Broadband Match Results Return Loss Smith Chart

  28. Problems and Conclusions • Matched at center frequency but return loss at band edges poor • Placed 150 ohm load at end to verify design • Conclusion • Q of antenna too high • System limited to highest Q • Power transfer sufficient for 5km range

  29. Testing Procedures • Wiport set up via serial interface • Each Wiport assigned an IP address • Terminal Emulation software used to communicate to the Wiport via serial • Wiport connects to remote host, transmits serial data via IP

  30. Testing Results • 18 April - Communication between Everitt, Grainger • 24 April – ½ mile test, South 1st St. • 25 April – 2 km test between Market Place Mall, Prospect & Olympian • Tests conducted at night in rainy conditions • 26 April – 650 m demonstration between Everitt, Beckman Parking Structure • Distances verified via GPS

  31. Conclusions • Benefits • Inexpensive • Low Power • Design Considerations • Robust • Reliable • Repeatable

  32. Acknowledgements • Professor Scott Carney • Dr. Ron Larkin • Ben Kamen • Shenghui Zhang • Professor Steven Franke • Professor Jennifer Bernhard • Professor Eric Michielssen

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