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Project: IEEE P802.15 Working Group for

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) 15-07-0778-00-0ban Submission Title: FM-UWB: A Low Complexity Constant Envelope LDR UWB Communication System Date Submitted: 16 July, 2007 Source: John F.M. Gerrits CSEM Systems Engineering

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Project: IEEE P802.15 Working Group for

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) 15-07-0778-00-0ban Submission Title: FM-UWB: A Low Complexity Constant Envelope LDR UWB Communication System Date Submitted: 16 July, 2007 Source: John F.M. Gerrits CSEM Systems Engineering JaquetDroz 1, CH2002 Neuchatel, Switzerland Voice: +41 32 720 56 52, FAX: +41 32 720 57 20, E-Mail: john.gerrits@csem.ch Re: This document is CSEM’s response to the Call For Application from theIEEE P802.15 Interest Group on BAN. Abstract:This document presents FM-UWB: a constant envelope LDR UWB air interface for short range BAN applications. 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. John F.M. Gerrits / John R. Farserotu, CSEM

  2. FM-UWB: A Low Complexity Constant Envelope LDR UWB Communication System John F.M. Gerrits & John R. Farserotu Wireless Communication Department CSEM Systems Engineering Switzerland http://www.csem.chhttp://www.fmuwb.ch John F.M. Gerrits / John R. Farserotu, CSEM

  3. Presentation Outline • Definition of and Applications for UWB • Principles and Performance of FM-UWB • Conclusions Aalborg University ACORDE CEA-LETI Lund University John F.M. Gerrits / John R. Farserotu, CSEM

  4. Definition of UWB • Bandwidth > 500 MHz for operation above 3.1 GHz • No particular air interface or modulation scheme specified • Signal needs to comply with the local spectral mask Over time, UWB has become less and less wideband.. John F.M. Gerrits / John R. Farserotu, CSEM

  5. Potential for UWB • High Data Rate MBOFDM 480 Mbps • Robust MDR, • Localization/tracking Impulse Radio 1-10 Mbps • Very Robust LDR FM < 250 kbps Very promising Business Potential. [http://www.techworld.com/mobility/] John F.M. Gerrits / John R. Farserotu, CSEM

  6. Low power consumption potential of UWB • The low radiated power of a UWB transmitter in principle may also yield • low power consumption. May yield, since power may be required to meet, • e.g., phase noise specifications or to perform baseband processing. • Usually, the receiver requires more power than the transmitter • (LNA gain, filtering, dynamic range) • A MB OFDM transceiver will never be the champion of the low power contest. John F.M. Gerrits / John R. Farserotu, CSEM

  7. Low-complexity UWB applications • Short range (1-10m) Wireless Sensor Networks for monitoring and control: • Applications: • Health monitoring BAN • Home automation • Security and alarms • Requirements: • Low cost, low power systems (mW - mWs) • Portable (go anywhere) • Robust and reliable • Good coexistence with other RF systems • Fast access (short synchronization time) BAN [IMEC] John F.M. Gerrits / John R. Farserotu, CSEM

  8. Robust constant–envelope UWB: analog spread-spectrum • FM-UWB is an analog implementation of a spread-spectrum system: • Spreading in transmitter by analog wideband FM (b = 500) • Despreading in receiver wideband FM demodulator, • yielding bandwidth reduction from 500 MHz to 200 kHz John F.M. Gerrits / John R. Farserotu, CSEM

  9. FM-UWB features • True Low-Compexity and Robustness to interference and multipath • - Relaxed hardware specs (phase noise) > very low power potential • - No carrier synchronization but instantaneous despreading • - CSMA techniques may enhance performance • - Antennas are not critical • - Steep spectral roll-off John F.M. Gerrits / John R. Farserotu, CSEM

  10. Analog spreading in transmitter BW: 50 kHz 200 kHz >500 MHz freq: baseband 1 -2 MHz 4.5 & 6-9 GHz FSK FM Sub carrier Data RF modulation spreading • An analog FM signal can have any bandwidth independent of modulation frequency or bit rate. • This is analog spread spectrum, i.e., multiple (b) copies of the FSK subcarrier signal. John F.M. Gerrits / John R. Farserotu, CSEM

  11. Data Subcarrier RF Data, subcarrier and FM-UWB signal in time domain John F.M. Gerrits / John R. Farserotu, CSEM

  12. Direct Digital Synthesis subcarrier generation No look-up tabe is required for the generation of a triangular waveform Data pre-filtering lowers subcarrier sidelobes to an acceptable level. fSUB = 1 MHz DfSUB = 50 kHz John F.M. Gerrits / John R. Farserotu, CSEM

  13. Relaxed phase noise requirements A Low-Power Ring Oscillator can do the job: Unmodulated at 4.5 GHz FM-UWB with Df = 250 MHz John F.M. Gerrits / John R. Farserotu, CSEM

  14. FM-UWB spectrum and Regulations FM-UWB fits everywhere; even in the European 4.2 – 4.8 and 6 – 9 GHz spectrum. FM roll-off TX phase noise TX white noise John F.M. Gerrits / John R. Farserotu, CSEM

  15. Instantaneous despreading in the receiver BW: >500 MHz 200 kHz 50 kHz freq: 4.5 & 6-9 GHz 1 -2 MHz baseband Subcarrier RF Data instantaneous despreading FSK demodulation 250 MHz GPdB = 34 dB @ 100 kbps GPdB = 44 dB @ 10 kbps 1 John F.M. Gerrits / John R. Farserotu, CSEM

  16. Receiver processing gain Only noise/interference in the subcarrier banwidth is taken into account. This bandwidth reduction after the wideband FM demodulator yields real processing gain: 250 MHz 1 Processing gain increases for lower bit rates: GPdB = 34 dB @ R = 100 kbps GPdB = 44 dB @ R = 10 kbps John F.M. Gerrits / John R. Farserotu, CSEM

  17. Wideband FM demodulator Phase det. FM>PM [ECWT 2006] John F.M. Gerrits / John R. Farserotu, CSEM

  18. Multiple RF and subcarrier signals in receiver At receiver input: 3 - 5 GHz (no multipath) After FM demod: FSK subcarriers: 1 – 2 MHz John F.M. Gerrits / John R. Farserotu, CSEM

  19. Receiver synchronization time Due to the instantaneous despreading, only bit synchronization is required like in a narrowband FSK system! John F.M. Gerrits / John R. Farserotu, CSEM

  20. Multiple-access techniques • Multiple users can be accommodated in a number of ways: • IEEE 802.15.4 MAC (TDMA) for standard applications • RF FDMA, highest for QOS (no multiple-access interference) • Sub-carrier FDMA (“MAC-less”) for ultra low power applications • Proprietary MAC (TDMA) for sensor networks, e.g., WISENET John F.M. Gerrits / John R. Farserotu, CSEM

  21. RF FDMA techniques • Multiple users use different RF and sub-carrier frequencies • Highest QOS, since no multiple-access interference occurs • (no spectral overlap) John F.M. Gerrits / John R. Farserotu, CSEM

  22. Subcarrier FDMA techniques • Multiple users can share the same RF center frequency • And distinguish themselves using different subcarrier frequencies Subcarrier filtering, multiple-access interference and phase noise determine the performance limits. John F.M. Gerrits / John R. Farserotu, CSEM

  23. Some figures on FM-UWB robustness1 • Impulse Radio interference with SIR = -14 dB yields BER = 10-3 • MBOFDM interference with SIR = -15 dB yields BER = 10-3 • FM-UWB performs very well in frequency-selective channels • as we will illustrate shortly. 1values mentioned are for a 100 kbps system John F.M. Gerrits / John R. Farserotu, CSEM

  24. Performance with frequency-selective fading Channel impulse response (time domain) CM4 CM1 Channel transfer function (frequency domain) John F.M. Gerrits / John R. Farserotu, CSEM

  25. FM-UWB performs better with strong multipath CM11000 channel realizationsCM4 John F.M. Gerrits / John R. Farserotu, CSEM

  26. Good, flat and bad channels good flat bad John F.M. Gerrits / John R. Farserotu, CSEM

  27. Statistics with various channels Variations in RF sensitivity [dB] based upon 1000 channel realizations [More at ICUWB2007] John F.M. Gerrits / John R. Farserotu, CSEM

  28. Conclusions • FM-UWB is a Low-Complexity LDR UWB radio for BAN Applications: • Constant-envelope: low-voltage, low power • Analog spread-spectrum with instantaneous despreading • RX synchronization time only bit-sync. limited • Robustness to interference and multipath • Simple radio architecture John F.M. Gerrits / John R. Farserotu, CSEM

  29. Thank You! John F.M. Gerrits / John R. Farserotu, CSEM

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