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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) PowerPoint Presentation
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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Harris TG4a CFP Proposal Response] Date Submitted: [“January 2005”] Source: [Rick Roberts] Company [Harris Corporation] Address [MS 1/9842, Box 37, Melbourne, Fl. 32902-0037] Voice:[321-729-3018], FAX: [], E-Mail:[] Re: [Harris TG4a response to call for proposals.] Abstract: [Harris TG4a response to call for proposals] Purpose: [For presentation and consideration by the IEEE802.15.4a committee] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Rick Roberts (Harris Corporation)

  2. Hybrid UWB/UNB1 Communications with Ranging Four Classes of Devices Class 1 – Low Complexity UWB for Communications with Ranging Class 2 – Backwards Compatible UWB with RFI Protection Class 3 – UWB/UNB with propagated node into GPS denied areas Class 4 – High Precision UWB for Ranging with Communications Note 1: UNB stands for Ultra-Narrow Band … a technique that uses low frequency, continuous RF tones for ranging, that require practically no bandwidth for detection and processing. See slide 32. Rick Roberts (Harris Corporation)

  3. Class 1 UWB Communications with Ranging apartment 1 apartment 2 wireless thermostat AC AC Range Assisted Addressing Rick Roberts (Harris Corporation)

  4. Class 2 RFI Protected UWB Communications with Ranging Mobile Meter Reader Example GPS Equipped Truck Synthetic Triangulation Allows Precise Localization Rick Roberts (Harris Corporation)

  5. Class 3 UWB/UNB with propagated node into GPS denied areas propagated node into GPS denied area Public Safety Application UWB 20 m 50 m Low Frequency Ranging 20 m Back Channel Out-of-scope (non-ranging) 30 m 802.11 802.11 802.11 command post Rick Roberts (Harris Corporation)

  6. Mandatory UWB PHY Rick Roberts (Harris Corporation)

  7. Frequency Plan • Direct Sequence Spread Spectrum • -3 dB Bandwidth (each band): 666.7 MHz • Center Frequencies: Every 250 MHz (3.6 GHz to 10.1 GHz) 26 possible overlapping bands 3.6 GHz 10.1 GHz 3.1 GHz 10.6 GHz • Pulse Response: Root Raised Cosine, 25% Excess Bandwidth Fc(-3 dB)=333.3 MHz Fc +250 +333.3 Noise Bandwidth (NBW) = 666.6 MHz +416.6 Rick Roberts (Harris Corporation)

  8. Advantages of Multiple frequency bands • Allows coarse spectral shaping for ingress/egress RFI avoidance • Allows multi-user separation by frequency channels • Allows implementation of lower frequency bands in today’s CMOS interference 3.6 GHz 3.1 GHz Interference avoided by skipping a frequency band Rick Roberts (Harris Corporation)

  9. Narrower Bandwidth, Spectrally Shaped UWB, Offers Advantages • Spectral Shaping Results in more NBW which means more TX power • 25% Excess BW, Raised Cosine Pulse • -10 dB bandwidth: 708 MHz • NBW: 667 MHz • Gaussian Pulse • -10 dB bandwidth: 708 MHz • NBW: ~388 MHz • Raised Cosine Pulse Power Advantage: ~2.35 dB • More power, better controlled spectrum • Wider Wavelets offer implementation advantage • Less complexity if a RAKE is deployed • 666.6 MHz of bandwidth still offers good multipath resolution Rick Roberts (Harris Corporation)

  10. Spectral Shaping within a frequency channel • “delay and add” notch formation • delay may be either a delay line or second impulse generator f f t0 t1 Rick Roberts (Harris Corporation)

  11. CDMA spread spectrum within each frequency channel • Chipping rate 666.6 Mcps, 25% root raised cosine, Nyquist filtering • Bit Rate (Rb) options (1 bit per symbol) • Coherent: 1 Mbps, 500 Kbps, 250 Kbps, 125 Kbps • Non-Coherent: 62.5 Kbps • Symbol Duration >> Delay Spread (shouldn’t need DFE) • Number of chips per bit • 1 Mbps: 666 • 500 kbps: 1332 • 250 kbps: 2664 • 125 kbps: 5328 • 62.5 Kbps: 10656 • Actual codewords are TBD (ternary symbols: +1, -1, 0) • Processing gain (PG): 28.2 dB to 40.3 dB • PG = 10*log10(NBW/Rb) = 10*log10(666.6e6/Rb) Rick Roberts (Harris Corporation)

  12. Advantages of high chipping rate • Minimizes the time waveform peak to average ratio • Each individual chip has low amplitude (integrated in the receiver) • Ternary codes: number of active chips per symbol is TBD • Enables high degree of integration on low voltage CMOS • Large code space allows selection of a number of good codes • Ternary codes are best for low cross-correlation • Time hopping codes are a possibility • Having a large number of codes allows code hopping multiple access Rick Roberts (Harris Corporation)

  13. Peak-to-Average: high chip rate vs. low chip rate Low Chip Rate Peak High Chip Rate Peak • For Equal TX Output, low chipping rate has a higher peak power and the high chipping rate has a lower peak power • Lower peak power is easier to integrate into low voltage semiconductor process Rick Roberts (Harris Corporation)

  14. SOP (Simultaneous Operating Piconets) • Two Methods to Accommodate SOP: • Multiple Frequency Channels (FDMA) • Within a frequency channel, use code division multiple access (CDMA) • Each of possible 4 CDMA piconets uses a chipping rate offset • Chipping rate offset prevents static cross correlation degradation Rick Roberts (Harris Corporation)

  15. Acquisition Preamble • Acquisition is strictly a function of SNR, not bit rate or symbol rate • For a given signal strength, the longer the preamble (observation time) the more robust the acquisition (more integration results in higher SNR) • Three preamble lengths: • Mandatory medium length preamble for normal use • Optional short preamble for higher mobility, high SNR scenarios • Optional long preamble for long range, low SNR scenarios • Acquisition can be either a code search (traditional spread spectrum) - or – • If SNR is high enough and channel is benign enough, use of a squaring loop enables cyclo-stationary assisted acquisition (recover carrier/clock frequency from collapsed spectrum – very useful for 62.5 Kbps non-coherent OOK) Rick Roberts (Harris Corporation)

  16. Two Modulation, Demodulation Modes 1. Coherent demodulation at Rb = 125 Kbps and higher Data Source Analog SP Digital SP Coded Wavelets Coded Wavelets 2. OOK (on-off keying) Non-Coherent demodulation at Rb = 62.5 Kbps Data Source ( )2 Analog SP Digital SP Coded Wavelets Rick Roberts (Harris Corporation)

  17. Coherent Demodulation Receiver Architecture (applying processing gain early reduces dynamic range requirements) Baseband Digital BPF I&D ADC Local Code Generator 1 MHz Local Wavelet Generator Rick Roberts (Harris Corporation)

  18. OOK Non-Coherent Demodulator Receiver Architecture • useful for short range, low complexity solutions • sub-optimal solution (degrades with interference or multipath) Fc=31.25 KHz OOK Decoder BPF ( )2 LPF ADC Offset Frequency Correction (could be done digitally) >= 62.5 KHz Sample Rate Rick Roberts (Harris Corporation)

  19. Optional Reed-Solomon FEC RS(38,32), GF(8), corrects 3 symbol errors … good burst error properties Rick Roberts (Harris Corporation)

  20. Acquisition Characteristics • Coherent Preamble • TBD • Very Robust, Long Range Acquisition • Good in Multipath and SOP Performance • More Overhead • Non-Coherent Preamble • TBD • Less Robust, Short Range Acquisition • Poorer in Multipath and SOP Performance • Less Overhead Rick Roberts (Harris Corporation)

  21. Link Margin Tables (Coherent Demodulation) Rick Roberts (Harris Corporation)

  22. Link Margin Table (Non-Coherent Demodulation) Rick Roberts (Harris Corporation)

  23. Received packets Tround TOF A B TOF Response Delay Preamble Acquisition Header Channel Acquisition Communication Payload Synchro H Elapsed times measured by the system Ranging is based upon Two Way Ranging, Time of Arrival (TWR-TOA) Figure 2: Two Way Ranging (TWR) transaction enabling to estimate the round-trip Time-OF-Flight between two asynchronous terminals (feeding TOA-based positioning algorithms) Rick Roberts (Harris Corporation)

  24. Positioning from TOA 3 anchors with known positions (at least) are required to retrieve a 2D-position from 3 TOAs Anchor 2 (xA2,yA2) Anchor 1 (xA1,yA1) Mobile (xm,ym) Anchor 3 (xA3,yA3) Estimated Position Measurements Specific Positioning Algorithms Positioning from TOA Rick Roberts (Harris Corporation)

  25. MSC for TWR TOA/TDOA token exchange The time of flight between the two devices is then calculated as Tflight = {T1(3) - T1(0) - τ}/2 where the time epochs are defined in the figure. Rick Roberts (Harris Corporation)

  26. Ranging Token: TBD Rick Roberts (Harris Corporation)

  27. PHY SAP - START CLOCK COMMAND High Rate Clock Local PHY Trigger Mechanism (TBD) PHY Correlator start Counter stop Vthresh count High Rate PHY Clock Rick Roberts (Harris Corporation)

  28. Channel Model PerformanceTBD Rick Roberts (Harris Corporation)

  29. MAC Modifications Rick Roberts (Harris Corporation)

  30. PHY PIB ranging attributes For suggested MLME primitive and parameter modifications, see document 15-04-0581-06-004a. Rick Roberts (Harris Corporation)

  31. MLME-RANGE primitive and parameters Rick Roberts (Harris Corporation)

  32. Optional Low Frequency PHY Rick Roberts (Harris Corporation)

  33. GPS Extension IndoorsUsing Near Field Electromagnetic Ranging Technology • Uses penetrating, narrow band, low frequency, low power signals (typically in the AM broadcast band, operating under Part 15 authorization). • Indoor propagation testing confirms accuracy of better than 4 m at ranges up to 70 m Rick Roberts (Harris Corporation)

  34. GPS Extension IndoorsPrototype Hardware • Receiver uses two orthogonal magnetic crossed loops and one electric antenna. • Transmitter uses a 2 foot whip antenna. • Operating frequency 1295 kHz Rick Roberts (Harris Corporation)

  35. GPS Extension IndoorsPropagation Testing • Approximately 40 m x 60 m steel frame industrial building w steel stud walls located in Huntsville, Alabama. Rick Roberts (Harris Corporation)

  36. GPS Extension IndoorsPropagation Testing • The building offers achallenging propagation environment complete with a corrugated metal wall dividing the old front half of the building from the new back half. • Forty interior points (numbered rectangles) yielded measurements from 10 m to 70 m. Rick Roberts (Harris Corporation)

  37. GPS Extension IndoorsPropagation Testing • Data taken from three points offset 10-20 m from the building (blue stars). Rick Roberts (Harris Corporation)

  38. GPS Extension IndoorsPropagation Testing • Mean error < 4m • Range >70 m (ran out of space in building!) Rick Roberts (Harris Corporation)

  39. Optional High Precision UWB PHY Rick Roberts (Harris Corporation)

  40. High Precision UWB TOA Implies Wide Bandwidth Rick Roberts (Harris Corporation)

  41. TBD Rick Roberts (Harris Corporation)