VHF/UHF Energy Harvesting Radio Systems PHY/MAC Layer Considerations Xiaohu Zhang Graduate Committee: William B. Kuhn Bala...
Outline <ul><li>Background and Challenges on Wireless Sensor Networks & Nodes </li></ul><ul><li>Solution for the Challenge...
Outline <ul><li>Background & Challenges on Wireless Sensor Networks & Nodes </li></ul><ul><ul><li>Wireless Sensor Nodes & ...
Wireless Sensor Node & Existing Research <ul><li>Wireless Sensor Node ( WSND) </li></ul><ul><ul><li>Radio </li></ul></ul><...
Challenges of Future Wireless Sensor Node <ul><li>Power source </li></ul><ul><ul><li>Battery-based source guarantee RF com...
Outline <ul><li>Background & Challenges on Wireless Sensor Networks & Nodes </li></ul><ul><li>Solution for the challenges ...
Solution for the Challenges of Wireless Sensor Node <ul><li>Power source </li></ul><ul><ul><li>Energy Harvesting technique...
R&D of EHR <ul><li>Propagation of 4 VHF/UHF frequencies </li></ul><ul><ul><li>RF Link budget </li></ul></ul><ul><ul><li>An...
R&D of EHR <ul><li>Propagation of 4 VHF/UHF frequencies </li></ul><ul><ul><li>RF Link budget </li></ul></ul><ul><ul><li>An...
RF Link Budget <ul><li>(1)The link budget equation  </li></ul><ul><li>(2)The path loss is proportional to the operation fr...
e.g. RF Link Budget <ul><li>In this calculation, assume Pr = 10Pn, Pn=kTB. B is bandwidth 1kHz.  </li></ul><ul><li>Figures...
Propagation Measurement <ul><li>Links </li></ul><ul><ul><li>Monopole antenna both ends </li></ul></ul><ul><ul><li>Directio...
Propagation Measurement <ul><li>Transmitter </li></ul>Agilent N9320 spectrum analyzer services as a receiver with the ante...
Antennas S11--151MHz & 433MHz
Antennas S11--902MHz & 2400MHz
Propagation & Path-loss Exponent Measurement Results <ul><li>Directional antenna has 6dB better than monopole antenna rece...
Comparison of Four Frequency Propagation <ul><li>At same receive power level (-120dBm) </li></ul><ul><ul><li>151MHz achiev...
Satellite view of the test path
R&D of EHR <ul><li>Propagation of 4 VHF/UHF frequencies </li></ul><ul><ul><li>RF Link budget </li></ul></ul><ul><ul><li>An...
Burst Communication
K-State Energy Harvesting Radio prototype Table 2‑1 Demo board Electrical Specification
Energy Harvester and Storage <ul><li>Solar Cell  (4 pcs) </li></ul><ul><ul><li>2.7v dc, 0.16mA dc ( under a 40Watt incande...
Duty cycle 1.1%--- 4MHz Clock Speed Design
Lab Test Figure-A 4 burst  clusters with 1% duty cycle Figure-B 1 active period : command & data signal Figure-C 5 burst d...
Outdoor Test <ul><li>(a) Satellite view of 0.2km transmission range </li></ul><ul><li>(b) view look back from parking lot ...
Implementation of solution <ul><li>Propagation of 4 VHF/UHF frequencies </li></ul><ul><ul><li>RF Link budget </li></ul></u...
<ul><li>PHY specification </li></ul><ul><ul><li>Preamble 32bits~40bits </li></ul></ul><ul><ul><li>SOF 8bits~20bits </li></...
IEEE802.15.4 Synchronization Study <ul><li>Synchronization </li></ul><ul><ul><li>Periodic Beacon Frame (peer-peer) </li></...
IEEE802.15.4 Sync CANNOT Work for EHR Systems <ul><li>EHR requires ultra-low duty cycle ≤2% </li></ul><ul><li>Long active ...
EHR Synchronization solution (1)  pure-EHR network <ul><li>Pure-EH network </li></ul><ul><ul><li>All devices are EHR  in t...
EH Radio Synchronization solution(1)   pure-EHR network <ul><li>Maximum synchronization duration  T maxSYNC </li></ul><ul>...
EH Radio Synchronization solution (2)   Hybrid-EHR network <ul><li>Ultra-low duty cycle (eg.<0.8%) w/ plenty spectrum reso...
EH Radio Synchronization solution (2)   Hybrid-EHR network <ul><li>Ultra-low duty cycle (eg.<0.8%) w/ limited spectrum cha...
EHR Recevier PHY DSP Development <ul><li>K-State Micro-Transceiver Demo V2.0 board </li></ul><ul><li>PIC24HJ256 </li></ul>...
PHY DSP Test <ul><li>±10kHz deviation modulation signal @433.92MHz </li></ul><ul><li>Test Environment </li></ul><ul><ul><l...
PHY DSP Test  (continue) <ul><li>“ Zero-cross” detector & PWM pulse generator </li></ul><ul><li>Bit-sync data vs. clock </...
Shrink PHY package size---by shortening Preamble Length Figure 4‑13 SOF detection with various preamble Length  <ul><li>Pr...
Preamble Length vs. Energy consumption-result Figure 4‑14 Energy Consumption VS. Preamble Length <ul><li>Result </li></ul>...
Summary & Challenges <ul><li>Summary </li></ul><ul><ul><li>Developed an EHR prototype  </li></ul></ul><ul><ul><li>Measured...
Thanks & Questions
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UHF/VHFEnergy Harvesting Radio System Physical and MAC Layer Consideration

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This is my defence slides. There are three parts been talked :
(1) Background and challenges on wireless sensor networks and nodes;
(2) Solutions for the challenges of wireless sensor nodes;
(3) Summary and future research directions.

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UHF/VHFEnergy Harvesting Radio System Physical and MAC Layer Consideration

  1. 1. VHF/UHF Energy Harvesting Radio Systems PHY/MAC Layer Considerations Xiaohu Zhang Graduate Committee: William B. Kuhn Bala Natarajan Don Gruenbacher May 2009
  2. 2. Outline <ul><li>Background and Challenges on Wireless Sensor Networks & Nodes </li></ul><ul><li>Solution for the Challenges of Wireless Sensor Nodes </li></ul><ul><li>Summary & Future Research Directions </li></ul>
  3. 3. Outline <ul><li>Background & Challenges on Wireless Sensor Networks & Nodes </li></ul><ul><ul><li>Wireless Sensor Nodes & Existing Research </li></ul></ul><ul><ul><li>Challenges of Future Wireless Sensor Nodes </li></ul></ul><ul><li>Solution for the challenges of Wireless Sensor Nodes </li></ul><ul><li>Summary & Challenges </li></ul>
  4. 4. Wireless Sensor Node & Existing Research <ul><li>Wireless Sensor Node ( WSND) </li></ul><ul><ul><li>Radio </li></ul></ul><ul><ul><ul><li>IEEE802.15.4 / 4a Standard </li></ul></ul></ul><ul><ul><ul><ul><li>Defined PHY/MAC layer only </li></ul></ul></ul></ul><ul><ul><li>Sensors </li></ul></ul><ul><ul><ul><li>Temporary, vibration, Humidity… </li></ul></ul></ul><ul><li>Current Research on WSND </li></ul><ul><ul><li>Battery Life improvement [1] </li></ul></ul><ul><ul><li>Energy Management [2] </li></ul></ul><ul><ul><li>Energy Efficient Protocols </li></ul></ul><ul><ul><li>SoC chip design </li></ul></ul><ul><ul><ul><li>Integrate RISC processor core + IEEE802.15.4 RF front-end </li></ul></ul></ul><ul><ul><ul><li>TI, Microchip, CrossBow (TinyOS) </li></ul></ul></ul><ul><ul><ul><li>[1] Everlast : Long-life, Supercapacitor-operated Wireless Sensor Node, Simjee, F., Chou, P.H., Lower Power Electronics and Design, 2006, ISLPED’06. Proceedings of the 2006 International Symposium </li></ul></ul></ul><ul><ul><ul><li>[2] A Power Management Architecture for Sensor Nodes , Eliasson, J, Lindgren, P., Delsing, J., Tompson, S.J, Yi-Bing Cheng, Wireless Communications and Networking Conference, 2007. WCNC 2007. IEEE </li></ul></ul></ul>
  5. 5. Challenges of Future Wireless Sensor Node <ul><li>Power source </li></ul><ul><ul><li>Battery-based source guarantee RF communication reliability  </li></ul></ul><ul><ul><li>Battery changing is a HUGE cost  </li></ul></ul><ul><li>RF communication mode VS. power consumption </li></ul><ul><ul><li>Continues TX/RX mode transmits more data  </li></ul></ul><ul><ul><li>Continues TX/RX mode leads higher power consumption  </li></ul></ul><ul><li>RF Link budget VS. System performance </li></ul><ul><ul><li>Higher frequency allows high data rate but short range   </li></ul></ul><ul><ul><li>Lower frequency limits the data rate but long range   </li></ul></ul><ul><li>Antenna technology & PHY Layer design </li></ul><ul><ul><li>Antenna could improve RF propagation  </li></ul></ul><ul><ul><li>High frequency w/ high data rate requires complex PHY Layer design </li></ul></ul><ul><ul><ul><li>multi-path, small-scale fading—Using dual-antenna? CDMA Rake Reciver?  </li></ul></ul></ul><ul><ul><li>Lower frequency leads bigger antenna size  </li></ul></ul><ul><li>Synchronization </li></ul><ul><ul><li>Keep to sync costing lots of power – RF keep working  </li></ul></ul><ul><li>Low power circuits </li></ul><ul><ul><li>SoC provides a compact solution  </li></ul></ul><ul><ul><li>Design cost and development cycle is long  </li></ul></ul>
  6. 6. Outline <ul><li>Background & Challenges on Wireless Sensor Networks & Nodes </li></ul><ul><li>Solution for the challenges of Wireless Sensor Nodes </li></ul><ul><ul><li>Solution for The Challenges </li></ul></ul><ul><ul><li>R&D of The Solution </li></ul></ul><ul><li>Summary & Challenges </li></ul>
  7. 7. Solution for the Challenges of Wireless Sensor Node <ul><li>Power source </li></ul><ul><ul><li>Energy Harvesting techniques </li></ul></ul><ul><li>RF communication mode VS. power consumption </li></ul><ul><ul><li>Burst communication mode + appropriate duty cycle </li></ul></ul><ul><li>RF Link budget VS. System performance </li></ul><ul><ul><li>Lower VHF/UHF frequency + Low data rate for long range </li></ul></ul><ul><li>Antenna technology & PHY Layer design </li></ul><ul><ul><li>Low frequency directional antenna at Base Station end </li></ul></ul><ul><ul><li>Antenna size could be shrunk 1/10 or more </li></ul></ul><ul><li>Synchronization </li></ul><ul><ul><li>Burst sync method with short preamble PHY frame </li></ul></ul><ul><li>Low power circuits </li></ul><ul><ul><li>K-State RFIC + PIC lower power microcontroller </li></ul></ul><ul><ul><ul><li>Reduce average power consumption </li></ul></ul></ul><ul><ul><ul><li>> 60% WSN has small data package: temperature, pressure... </li></ul></ul></ul><ul><ul><ul><li>Due to antenna reciprocity property </li></ul></ul></ul><ul><ul><ul><li>By using special material </li></ul></ul></ul><ul><ul><ul><li>Fair long sync duration trade in power consumption </li></ul></ul></ul><ul><ul><ul><li>KIS implementation </li></ul></ul></ul><ul><ul><ul><li>Solar </li></ul></ul></ul><ul><ul><ul><li>Thermal </li></ul></ul></ul><ul><ul><ul><li>Wind </li></ul></ul></ul><ul><ul><ul><li>MEMs </li></ul></ul></ul><ul><ul><ul><li>Biological energy </li></ul></ul></ul><ul><ul><ul><li>Kinetic </li></ul></ul></ul><ul><ul><ul><li>Radio wave </li></ul></ul></ul>Low Data Rate Long Distance Energy Harvesting Radio (EHR)
  8. 8. R&D of EHR <ul><li>Propagation of 4 VHF/UHF frequencies </li></ul><ul><ul><li>RF Link budget </li></ul></ul><ul><ul><li>Antenna technique </li></ul></ul><ul><ul><li>Propagation, pass loss exponents measurement </li></ul></ul><ul><li>Energy Harvesting Radio prototype </li></ul><ul><ul><li>Burst communication </li></ul></ul><ul><ul><li>Energy harvesting technique </li></ul></ul><ul><ul><li>Duty cycle design </li></ul></ul><ul><li>PHY/MAC Layer consideration for EHR systems </li></ul><ul><ul><li>IEEE802.15.4 PHY & MAC Sync challenges for EHR systems </li></ul></ul><ul><ul><li>EHR PHY & MAC Sync proposal </li></ul></ul><ul><ul><li>PHY Layer DSP implementation </li></ul></ul>
  9. 9. R&D of EHR <ul><li>Propagation of 4 VHF/UHF frequencies </li></ul><ul><ul><li>RF Link budget </li></ul></ul><ul><ul><li>Antenna technique </li></ul></ul><ul><ul><li>Propagation, pass loss exponents measurement </li></ul></ul><ul><li>Energy Harvesting Radio prototype </li></ul><ul><ul><li>Burst communication </li></ul></ul><ul><ul><li>Energy harvesting technique </li></ul></ul><ul><ul><li>Duty cycle design </li></ul></ul><ul><li>PHY Layer consideration for HER systems </li></ul><ul><ul><li>IEEE802.15.4 PHY & MAC Sync challenges for EHR systems </li></ul></ul><ul><ul><li>EHR PHY & MAC Sync proposal </li></ul></ul><ul><ul><li>PHY Layer DSP implementation </li></ul></ul>
  10. 10. RF Link Budget <ul><li>(1)The link budget equation </li></ul><ul><li>(2)The path loss is proportional to the operation frequency f squared ; N=2 is free space path loss exponent, vary from 1~6 depends on environment </li></ul><ul><li>(3) The antenna’s length is inversely proportional to its operation frequency </li></ul>
  11. 11. e.g. RF Link Budget <ul><li>In this calculation, assume Pr = 10Pn, Pn=kTB. B is bandwidth 1kHz. </li></ul><ul><li>Figures shows the path-loss exponent has the strongest effect on achieve range, and therefore must be well understood in any given applications. [1] </li></ul>[1] White Paper on Energy Harvesting Radio Transceivers, William B. Kuhn, 2007
  12. 12. Propagation Measurement <ul><li>Links </li></ul><ul><ul><li>Monopole antenna both ends </li></ul></ul><ul><ul><li>Directional antenna at TX; Monopole at RX </li></ul></ul><ul><ul><li>10mw transmitting power </li></ul></ul><ul><li>Environment </li></ul><ul><ul><li>Concrete foundation, wall supports, slab floor with metal supports and dry wall </li></ul></ul><ul><ul><li>Power and cable lines, air conditioning ducts, steel piping </li></ul></ul><ul><ul><li>10mw transmitter </li></ul></ul><ul><ul><li>Antennas </li></ul></ul>
  13. 13. Propagation Measurement <ul><li>Transmitter </li></ul>Agilent N9320 spectrum analyzer services as a receiver with the antenna 10mw transmitter Directional & Monopole antennas <ul><li>Receiver </li></ul><ul><li>Antennas </li></ul>
  14. 14. Antennas S11--151MHz & 433MHz
  15. 15. Antennas S11--902MHz & 2400MHz
  16. 16. Propagation & Path-loss Exponent Measurement Results <ul><li>Directional antenna has 6dB better than monopole antenna reception </li></ul><ul><li>IndoorN=3 OutdoorN=3.2 </li></ul><ul><li>Excess path loss 12dB </li></ul><ul><li>Directional antenna has 8dB better than monopole antenna reception </li></ul><ul><li>IndoorN=3.5 OutdoorN=4.3 </li></ul><ul><li>Excess path loss 10dB </li></ul><ul><li>Directional antenna has 12dB better than monopole antenna reception </li></ul><ul><li>IndoorN=4 OutdoorN=4.5 </li></ul><ul><li>Excess path loss 20dB </li></ul><ul><li>Directional antenna has 12.5dB better than monopole antenna reception </li></ul><ul><li>IndoorN=4.2 OutdoorN=4.8 </li></ul><ul><li>Excess path loss 29dB </li></ul>
  17. 17. Comparison of Four Frequency Propagation <ul><li>At same receive power level (-120dBm) </li></ul><ul><ul><li>151MHz achieve 1.46km </li></ul></ul><ul><ul><li>433MHz achieve 0.67km </li></ul></ul><ul><ul><li>902MHz achieve 0.54km </li></ul></ul><ul><ul><li>2400GHz achieve 0.2km </li></ul></ul><ul><li>At same distance point </li></ul><ul><ul><li>6dB 151MHz>433MHz </li></ul></ul><ul><ul><li>9dB 151MHz>902MHz </li></ul></ul><ul><ul><li>19dB 151MHz>2400MHz </li></ul></ul><ul><li>Directional antenna is used at transmitter end </li></ul><ul><li>Monopole antenna is used at receiver end </li></ul>
  18. 18. Satellite view of the test path
  19. 19. R&D of EHR <ul><li>Propagation of 4 VHF/UHF frequencies </li></ul><ul><ul><li>RF Link budget </li></ul></ul><ul><ul><li>Antenna technique </li></ul></ul><ul><ul><li>Propagation, pass loss exponents measurement </li></ul></ul><ul><li>EHR prototype </li></ul><ul><ul><li>Burst communication </li></ul></ul><ul><ul><li>Energy harvesting technique </li></ul></ul><ul><ul><li>Duty cycle design </li></ul></ul><ul><li>PHY Layer consideration for EHR systems </li></ul><ul><ul><li>PHY Layer DSP implementation </li></ul></ul><ul><ul><li>IEEE802.15.4 PHY & MAC Sync challenges for EHR systems </li></ul></ul><ul><ul><li>EHR PHY & MAC Sync proposal </li></ul></ul>
  20. 20. Burst Communication
  21. 21. K-State Energy Harvesting Radio prototype Table 2‑1 Demo board Electrical Specification
  22. 22. Energy Harvester and Storage <ul><li>Solar Cell (4 pcs) </li></ul><ul><ul><li>2.7v dc, 0.16mA dc ( under a 40Watt incandescent bulb with 6 inches distance ) </li></ul></ul><ul><ul><li>2.7v dc, 0.033mA dc ( under indoor fluorescent lights) </li></ul></ul><ul><li>Capacitor storage (220 μ f 4 pcs) </li></ul>
  23. 23. Duty cycle 1.1%--- 4MHz Clock Speed Design
  24. 24. Lab Test Figure-A 4 burst clusters with 1% duty cycle Figure-B 1 active period : command & data signal Figure-C 5 burst data Figure-D 433MHz modulation signal
  25. 25. Outdoor Test <ul><li>(a) Satellite view of 0.2km transmission range </li></ul><ul><li>(b) view look back from parking lot </li></ul><ul><li>(c) view looking inside hallway of RA2097 [1] </li></ul>[1] White Paper on Energy Harvesting Radio Transceivers, William B. Kuhn, 2007 (a) (b) (c)
  26. 26. Implementation of solution <ul><li>Propagation of 4 VHF/UHF frequencies </li></ul><ul><ul><li>RF Link budget </li></ul></ul><ul><ul><li>Antenna technique </li></ul></ul><ul><ul><li>Propagation, pass loss exponents measurement </li></ul></ul><ul><li>Energy Harvesting Radio prototype </li></ul><ul><ul><li>Burst communication </li></ul></ul><ul><ul><li>Energy harvesting technique </li></ul></ul><ul><ul><li>Duty cycle design </li></ul></ul><ul><li>PHY Layer consideration for EHR systems </li></ul><ul><ul><li>IEEE802.15.4 PHY & MAC Sync challenges for EHR systems </li></ul></ul><ul><ul><li>EHR PHY & MAC Sync proposal </li></ul></ul><ul><ul><li>PHY Layer DSP implementation </li></ul></ul>
  27. 27. <ul><li>PHY specification </li></ul><ul><ul><li>Preamble 32bits~40bits </li></ul></ul><ul><ul><li>SOF 8bits~20bits </li></ul></ul><ul><ul><li>PHY payload 72bits~232bits </li></ul></ul><ul><ul><li>Super Frame (Active / Inactive) </li></ul></ul><ul><ul><li>BI (Beacon Interval) </li></ul></ul>IEEE802.15.4 PHY Study
  28. 28. IEEE802.15.4 Synchronization Study <ul><li>Synchronization </li></ul><ul><ul><li>Periodic Beacon Frame (peer-peer) </li></ul></ul><ul><ul><li>Variable duty cycle configuration </li></ul></ul><ul><ul><li>Maximum synchronization time </li></ul></ul><ul><ul><ul><li>[ aBaseSuperframeDuration*(2n+1) ] </li></ul></ul></ul><ul><ul><ul><ul><li>3.12s —1.6%, 20kbps, 868MHz, BPSK </li></ul></ul></ul></ul><ul><ul><ul><ul><li>49.2s —0.1%, 20kbps, 868MHz, BPSK </li></ul></ul></ul></ul>
  29. 29. IEEE802.15.4 Sync CANNOT Work for EHR Systems <ul><li>EHR requires ultra-low duty cycle ≤2% </li></ul><ul><li>Long active period leads HUGE capacitor’s voltage drop </li></ul><ul><ul><li>E.g. K-State EH Radio, 4*220uF capacitors, 30ms-Active, Sync time is 3.12s (1.6%) with 20.5mA, 72.7v drop  </li></ul></ul>
  30. 30. EHR Synchronization solution (1) pure-EHR network <ul><li>Pure-EH network </li></ul><ul><ul><li>All devices are EHR in the network </li></ul></ul><ul><ul><li>Scanning beacon frame for at least T SB =2* T SLOT each wake up period; (one slot is 3ms of IEEE802.15.4 for 20kbps) </li></ul></ul><ul><ul><li>Sleep a defined inactive duration T BI when 1 st time enter inactive mode. Then wake up to receive T SB ; </li></ul></ul><ul><ul><li>Sleep a T BI +1*T SLOT when 2 nd time enter inactive mode, then wake up to receive T SB ; </li></ul></ul><ul><ul><li>Sleep a T BI +2*T SLOT when 3 rd time enter inactive mode, then wake up to receive T SB ; </li></ul></ul><ul><ul><li>Sleep T BI +n*T SLOT when (n+1) time enter inactive mode …… </li></ul></ul><ul><ul><li>Running Active / Inactive alternately with defined duty cycle when a beaconframe is detected. </li></ul></ul><ul><li>Beacon searching process </li></ul><ul><li>Beacon detected process </li></ul>
  31. 31. EH Radio Synchronization solution(1) pure-EHR network <ul><li>Maximum synchronization duration T maxSYNC </li></ul><ul><ul><li>Maximum synchronization duration (4.4) </li></ul></ul><ul><ul><li>Beacon interval duration (4.5) </li></ul></ul><ul><ul><li>Slots number in one beacon interval duration (4.6) </li></ul></ul>Table 4-3 Sync time and power consumption comparison of EH radio and IEEE802.15.4 standard radio (*The active duration voltage drop is calculated by using equation (2.3) and assume active/inactive current are 20.5mA and 0.06mA, these number came from Chapter 2, Duty Cycle Design, section “Low CPU Clock, Hardware control TX”) Figure 4-10 EH Radio Sync time versus Duty cycle
  32. 32. EH Radio Synchronization solution (2) Hybrid-EHR network <ul><li>Ultra-low duty cycle (eg.<0.8%) w/ plenty spectrum resource </li></ul><ul><ul><li>Hybrid : Coordinator is not EHR, which has power supply </li></ul></ul><ul><ul><li>Pilot channel : to transmit beacon frame continuously </li></ul></ul><ul><ul><li>Data channel : to transmit data only </li></ul></ul>
  33. 33. EH Radio Synchronization solution (2) Hybrid-EHR network <ul><li>Ultra-low duty cycle (eg.<0.8%) w/ limited spectrum channel </li></ul><ul><ul><li>Coordinator is not EHR but has power supply </li></ul></ul><ul><ul><li>Shared Pilot / Data channel : to transmit beacon frame and data </li></ul></ul>
  34. 34. EHR Recevier PHY DSP Development <ul><li>K-State Micro-Transceiver Demo V2.0 board </li></ul><ul><li>PIC24HJ256 </li></ul><ul><ul><li>F OSC is 19.2 MHz; </li></ul></ul><ul><ul><li>F CY is F OSC /2= 0.104us </li></ul></ul><ul><ul><li>3.3v power supply </li></ul></ul><ul><li>PHY DSP Data flow diagram </li></ul>
  35. 35. PHY DSP Test <ul><li>±10kHz deviation modulation signal @433.92MHz </li></ul><ul><li>Test Environment </li></ul><ul><ul><li>RIGOL DG 2021A function/Arbitrary waveform generator </li></ul></ul><ul><ul><li>HP 8648 Signal Generator--FSK@433.92MHz </li></ul></ul><ul><ul><li>Agilent 54622D Oscilloscope </li></ul></ul><ul><ul><li>ESA-L150000A Spectrum Analyzer </li></ul></ul><ul><ul><li>DUT </li></ul></ul>
  36. 36. PHY DSP Test (continue) <ul><li>“ Zero-cross” detector & PWM pulse generator </li></ul><ul><li>Bit-sync data vs. clock </li></ul><ul><li>Data recovering </li></ul>
  37. 37. Shrink PHY package size---by shortening Preamble Length Figure 4‑13 SOF detection with various preamble Length <ul><li>Preamble length occupy over 1/5 of PHY package of IEEE802.15.4 (xx~xxbits) </li></ul><ul><li>Shorter, Lower EBR is good </li></ul><ul><li>6bits & 10 bits Preamble leads higher Error Prob of the SOF </li></ul>1 2 <ul><li>1. Improve shorter preamble performance by using </li></ul><ul><ul><li>Dynamic Bit-sync state machine lock window </li></ul></ul><ul><ul><li>Adaptive TX power on preamble </li></ul></ul><ul><li>Improve receive sensitivity </li></ul><ul><ul><li>Decrease System Noise Figure </li></ul></ul>
  38. 38. Preamble Length vs. Energy consumption-result Figure 4‑14 Energy Consumption VS. Preamble Length <ul><li>Result </li></ul><ul><li>Too short preamble frame leads higher energy consumption to satisfy specific error probability of SOF </li></ul><ul><li>The energy is linear slowly increasing along with preamble length increasing </li></ul><ul><li>Shorter PHY payload size will lead less energy consumption </li></ul>
  39. 39. Summary & Challenges <ul><li>Summary </li></ul><ul><ul><li>Developed an EHR prototype </li></ul></ul><ul><ul><li>Measured VHF/UHF frequency propagation (Published one paper RWS2009) </li></ul></ul><ul><ul><li>Proposed EHR systems PHY layer frame structures </li></ul></ul><ul><ul><li>Proposed EHR systems MAC layer synchronization method </li></ul></ul><ul><ul><li>Developed EHR Receiver PHY layer DSP software </li></ul></ul><ul><li>Challenges </li></ul><ul><ul><li>Low speed interactive communication capability </li></ul></ul><ul><ul><li>Keeping Synchronization </li></ul></ul>
  40. 40. Thanks & Questions

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