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Project: IEEE 802.15 WPAN Low Rate Alternative PHY Task Group 4a (TG4a)

Project: IEEE 802.15 WPAN Low Rate Alternative PHY Task Group 4a (TG4a) Submission Title: [ FM-UWB: A Low Complexity Low Data Rate Constant Envelope UWB Communications System ] Date Submitted: [ 7 January, 2005 ] Source: [ John F.M. Gerrits ] Company [ CSEM ]

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Project: IEEE 802.15 WPAN Low Rate Alternative PHY Task Group 4a (TG4a)

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  1. Project: IEEE 802.15 WPAN Low Rate Alternative PHY Task Group 4a (TG4a) Submission Title: [FM-UWB: A Low Complexity Low Data Rate Constant Envelope UWB Communications System] Date Submitted: [7 January, 2005] Source: [John F.M. Gerrits] Company [CSEM] Address [Jaquet Droz 1, CH2007 Neuchatel, Switzerland] Voice:[+41 32 720 56 52], FAX: [+41 32 720 57 20], E-Mail:[john.gerrits@csem.ch] Re: [IEEE P802.15 LDR ALT PHY Call For Proposals] Abstract: [This document presents a novel constant envelope LDR UWB air interface for the IEEE P802.15 ALT PHY ] Purpose: [For information to IEEE 802.15.4a Task Group by CSEM Switzerland] 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 Low Data Rate Constant Envelope UWB Communications System for PAN/BAN applications. John F.M. Gerrits / John R. Farserotu Wireless Communications Department CSEM Systems Engineering Switzerland http://www.csem.ch John F.M. Gerrits / John R. Farserotu, CSEM

  3. Motivation for FM-UWB • Impulse radio has proven to be a good solution for HDR UWB systems. • It requires pulse synchroniation and accurate timing. • We believe that it is not necessarily the best approach for a simple, low-cost, • low-power, short-range, LDR communiciations system for PAN/BAN applications. Since the definition of a UWB signal does not specify a particular air interface or modulation scheme, many different techniques may be applicable to a UWB signal. • More established modulation schemes may be used • to generate a UWB signal. John F.M. Gerrits / John R. Farserotu, CSEM

  4. FM-UWB, How does it work? Analog frequency modulation has the unique property that the RF bandwidth BRF is not only related to the bandwidth fm of the modulating signal, but also to the modulation index b that can be chosen freely. High modulation index FM can be seen as an analog implementation of a spread spectrum system with spreading gain equal to the modulation index b. The power spectral density of a wideband FM signal has the shape of the probability density function of the modulating signal (subcarrier). A triangular subcarrier signal will yield a flat RF UWB spectrum with steep spectral roll-off. By modulating the subcarrier, data can be transmitted. John F.M. Gerrits / John R. Farserotu, CSEM

  5. FM-UWB Transmitter • FM • FSK FSK subcarrier • [1, 2] John F.M. Gerrits / John R. Farserotu, CSEM

  6. FM-UWB Spectrum and Coexistence FM-UWB uses a high modulation index FM signal Modulated by a low-frequency triangular signal (fSUB) An analog spread spectrum system Bandwidth: BRF = 2(Df+ fSUB) PSD lowered by 10 log10(Df /fSUB) For Df = 600 MHz, fSUB = 1 MHz PSD reduced 28 dB Flat power spectral density Rapid spectral roll-off John F.M. Gerrits / John R. Farserotu, CSEM

  7. FM-UWB Receiver FSK subcarriers • A multi-user system can be realized by: • FDMA at sub-carrier level • FDMA at RF carrier level • TDMA tecniques John F.M. Gerrits / John R. Farserotu, CSEM

  8. FDMA subcarrier techniques 3 x 10 kbit/s 1 x100 kbit/s subcarrier frequency [MHz] • When the users share the same RF carrier frequency, simultaneous • demodulation of multiple signals must be performed in the receiver. • As in a DSSS system, the limit is multiple-access interference • (e.g., NMAX = 15 @ 100 kbit/s, NMAX = 150 @ 1 kbit/s). John F.M. Gerrits / John R. Farserotu, CSEM

  9. Wideband FM Delay Line Demodulator • This demodulator has been fully integrated on silicon. John F.M. Gerrits / John R. Farserotu, CSEM

  10. FM-UWB Performance in AWGN 500 MHz Processing gain = 2 R John F.M. Gerrits / John R. Farserotu, CSEM

  11. Robustness to MB-OFDM UWB signals SIR = -10 dB BER < 1x10-6 John F.M. Gerrits / John R. Farserotu, CSEM

  12. Power Consumption Projections Power consumption estimates for FM-UWB (continuous): - Transmitter 2 mW, Receiver 5 mW These values can definitely compete with ISM solutions. - Lower values possible dependent on duty cycle John F.M. Gerrits / John R. Farserotu, CSEM

  13. IC Technology Requirements Rx Tx A good CMOS or BiCMOS techno (fT = 100 GHz), low VTand low VDD(1 V), on-chip passives with moderate Q factor. John F.M. Gerrits / John R. Farserotu, CSEM

  14. Frequency Domain Localization FMCW radar • 1 GHz 1 m • 6.67 MHz • 1 ms 3x108 m/s • [3, 4] John F.M. Gerrits / John R. Farserotu, CSEM

  15. FM-UWB Features • Simple hardware implementation compatible with IC technology • Low power consumption • Relaxed hardware specs (antenna, phase noise, component tolerances) • Receiver requires no local oscillator • No carrier synchronization (as in impulse radio) • Scalable technology • Steep spectral roll-off • Robustness to MB-OFDM interference and multipath • CSMA techniques can enhance performance • Localization compatibility John F.M. Gerrits / John R. Farserotu, CSEM

  16. References [1] John F.M. Gerrits, John R. Farserotu, "Ultra Wide Band FM: A Constant Envelope Frequency Domain Approach",International Zurich Seminar on Communications (IZS), Feb. 18–20, 2004, Zürich, Switzerland, pp. 90 - 93. [2] John F.M. Gerrits, Michiel H.L. Kouwenhoven, Paul R. van der Meer, John R. Farserotu, John R. Long, "Principles and Limitations of UWBFM Communications Systems", accepted by the EURASIP Journal of Applied Signal Processing [3] John F.M. Gerrits, John R. Farserotu, John R. Long, "UWB Considerations for “My Personal Global Adaptive Network” (MAGNET) Systems", Proceedings of the 30th European Solid-State Circuits Conference, ESSCIRC 2004, Leuven, Belgium, 21-23 September 2004, pp. 45-56. [4] John F.M. Gerrits, John R. Farserotu, John R. Long, "UWBFM: A Low and Medium Data Rate Constant Envelope UWB Communications System with Localization Potential". MAGNET Workshop, November 11-12, Shanghai John F.M. Gerrits / John R. Farserotu, CSEM

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