November 2003 doc IEEE 802 15 03 0460
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Introduction to Chirp Spread Spectrum (CSS) Technology Date Submitted: November 11, 2003 Source: John Lampe, Zbigniew Ianelli Company: Nanotron Technologies Address: Alt-Moabit 61, 10555 Berlin, Germany Voice: +49 30 399 954 135, FAX: +49 30 399 954 188, E-Mail: j. lampe@nanotron. com Re: Discussion of interesting RF technology Abstract: Tutorial Presentation on CSS for IEEE 802 – part 1 Purpose: November Plenary Tutorial #4. Notice: This document has been prepared to assist the IEEE P 802. 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 P 802. 15. Submission 1 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Introduction to Chirp Spread Spectrum (CSS) Technology presented by Zbigniew Ianelli Nanotron Technologies Gmb. H Berlin, Germany www. nanotron. com Submission 2 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Contents • • A brief history of Chirp pulses Characteristics of Chirp pulses The basic Chirp signal Properties of signal forms Scalable technology How to code using CSS Key Properties of CSS Submission 3 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 A brief history of Chirp pulses • Used by whales and dolphins • Patent for radar applications in 1944 by Prof. Hoffmann • Further developed by Sidney Darlington (Lifetime IEEE Fellow) in 1947 („Pulse Compression Radar“) • Patented by Canon for data transmission in fiber optic systems • Chirp Spread Spectrum for commercial wireless data transmission is investigated since 1997 Submission 4 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Characteristics of Chirp pulses • A chirp pulse is a frequency modulated pulse. • Its duration is T; within this time the frequency is changing in a monotonic manner from a lower value to a higher one („Up-Chirp“) or reverse („Down-Chirp“). • The difference between these two frequencies is a good approximation for the bandwidth B of the chirp pulse. S(f) f B Up-Chirp in the time domain (roll-off factor 0. 25) Spectrum of the chirp pulse with bandwidth B and a roll-off factor of 0. 25 Submission 5 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 The basic Chirp signal Chirp pulse: Sinc pulse (baseband): Sinc pulse (RF band): Submission 6 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Properties of signal forms in the air and baseband interfaces Chirp pulses for the RF channel: • High robustness (BT>>1) • Wideband signal • Constant envelope of the RF waveform • Constant, uniform PSD (Power Spectral Density) well controlled spectrum in very simple way Sinc pulses in the baseband: • High speed (Bδ=1) • Easy signal processing (threshold detector) Submission 7 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Scalable Technology Frequency spreading: Basic information theory tells us that CSS benefits when the bandwidth B of the Chirp pulse is much higher than the data rate R: B >> R Time spreading: The data rate can scale independently of the BT product. The duration T of the Chirp pulse can be chosen freely. A signal with a very high BT product can be achieved, which transforms into a very robust signal in the channel. Submission 8 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Scalable Technology (continued) Excellent range – data rate scalability: Preferred for system where range and/or data rate requirement varies rapidly. Especially promising for wideband or ultra wideband system where available frequency bandwidth B is much higher than the data rate R Submission 9 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 How to code using CSS Modulation techniques: f f. HI On-Off-Keying (OOK), for example: 1 0 0 1 f. LO t Up-Chirp = „ 1“; Null = „ 0“ allows 2 independent coexisting networks Superposed Chirps (4 possible states): Chirp pulse Null/Up-Chirp/Down-Chirp/ Superposition of Up- and Down-Chirp allows one network with double the data rate Submission 10 OOK with Null and Up-Chirp Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Key Properties of CSS High robustness: Due to the high BT product, chirp pulses are very resistant against disturbances. Multipath resistant: Due to the broadband chirp pulse, CSS is very immune against multipath fading; CSS can even take advantage of RF echoes. Low power consumption: CSS allows the designer to choose an analog implementation, which often consumes much less power. Low latency: CSS needs no synchronization; a wireless connection can be established very quickly. Submission 11 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Mobility Properties of CSS Resistance against Doppler effect: The Doppler effect causes a frequency shift of the chirp pulse, which introduces a negligible shift of the baseband signal on the time axis. Example: Bandwidth of the chirp Duration of the chirp Center frequency of the chirp (ISM band) Relative speed between transmitter and receiver Frequency shift due to Doppler effect Equivalent shift of the message on the time axis 80 MHz 1 µs 2. 442 GHz 2000 km/h 4. 52 k. Hz 56. 5 ps Note: 2000 km/h is equivalent to 1243 miles/hour Submission 12 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Coexistence Properties of CSS Immune to in-band interferer: Scalable processing gain (determined by BT product of the chirp) enables selection of appropriate immunity level against in-band interferences. Example: Bandwidth B of the chirp Duration time T of the chirp Center frequency of the chirp (ISM band) Processing gain, BT product of the chirp Eb/N 0 at detector input (BER=0. 001) In-band carrier to interferer ratio (C/I @ BER=0. 001) 64 MHz 1 µs 2. 442 GHz 18 d. B 14 d. B -4 d. B Submission Lampe, Ianelli, Nanotron 13
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Some Applications and Measurements of Chirp Spread Spectrum (CSS) Technology presented by John Lampe Nanotron Technologies Gmb. H Berlin, Germany www. nanotron. com Submission 14 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 New Applications / Global Markets • Applications requiring mobility faster than 11 mph, such as: – Tire pressure – Assets in vehicles (in-car communications) – Drive-by • Drop boxes • Drive-by AMR – Toll booths • Applications requiring robustness or fewer retransmissions in multipath environments, such as: – – – • Industrial mission-critical Airplanes Ships / engine rooms Gaming New WINA alliance one example of this need Applications requiring ranging accuracy better than 0. 5 meters, such as: – – Submission Asset tracking (active RFID) Personnel tracking Motion detection Automatic network installation 15 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Enhanced Applications / Markets • Applications desiring extended range, such as: – Meter Reading – Building Automation – And other longer-range applications where repeaters are not practical Submission 16 Lampe, Ianelli, Nanotron
November 2003 Includes: doc. : IEEE 802. 15 -03 -0460 -00 -0000 Evaluation Board • RF IC • SAW filter • Optimized balun for asymmetrical antenna operation • Crystals Submission 17 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Comparing CSS to DECT Outdoors Submission 19 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Indoor testing with CSS d=23 m , Pou = -15 d. Bm t = 32 µW , G=1, 5 d. B, BER = 10 -3 2 3 = Bm -3 d 15 = 10 = ER ut o P , B m d 15 1, 5 = d , G= µW Result: d = 23 m with Pout = -15 d. Bm Calculated: d = 50 m with Pout = +10 d. Bm, a = 3 Submission 20 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Indoor testing with CSS d=5 m, Pout = -30 d. Bm= 1 µW, G = 1, 5 d. B, BER = 10 -4 d= 26 m, Po ut =8 d. Bm =6 , 3 m W, G= 1, 5 d B, B E R= 10 -3 Load-bearing Walls CSS transmits 1 Mbps with Pout = 1 µW over 5 m and with 6, 3 m. W over 26 m Submission 21 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Outdoor Link-Budget • Link budget without cable losses or antenna-gain, best case: LBbest = 103 d. B • Outdoor free space propagation: distance ~ linkbudget with = 2. 1 … 2. 3 • But: Outdoor propagation is not always free space propagation, due to e. g. hills, trees, houses, … • Therefore: Measurements have to be done! Submission d = 940 m 22 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Testing CSS on Hahneberg, Berlin-Spandau P 2 P 3 3404± 10 m P 1 4626± 10 m 739± 10 m P 4 940± 10 m Ref Submission 23 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Outdoor testing with CSS P 2 3404± 10 m P 3 P 1 4626± 10 m Pout = 24 d. Bm = 250 m. W 739± 10 m Pout = 7 d. Bm = 5 m. W P 4 Ref 940± 10 m Pout = 9 d. Bm = 7. 9 m. W Submission 24 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Outdoor testing with CSS Measurement Challenge: Teufelsberg • 6483 m distance • 7. 7 d. Bm output power • 18 d. B antenna gain • No FEC • BER 10 E-3 Submission 25 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 CSS Outdoor Test Summary Pout = 30 d. Bm, d = 9. 8 km Pout = 26 d. Bm, d = 6. 4 km Pout = 7 d. Bm, d = 740 m Pout = 9 d. Bm, d = 940 m Gant = 1 d. B Output Power @ antenna 7 d. Bm = Range @ BER=10 -3 5 m. W 740 m 9 d. Bm = 7. 9 m. W 940 m 26 d. Bm = 400 m. W 6400 m 30 d. Bm = 1 Submission W 9800 m 26 Lampe, Ianelli, Nanotron
<month year> doc. : IEEE 802. 15 -03 -0460 -00 -0000 Need for Standardization Ole Ploug R&D Manager Central Controls R&D Refrigeration and Air Conditioning www. danfoss. com Submission 27 <author>, <company>
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Summary • Introduced CSS technology • Explained behavior and benefits • Suggested some additional applications that can be satisfied • Shown test results that demonstrate some of CSS’ capabilities • Shown one customer’s application requirements Submission 28 Lampe, Ianelli, Nanotron
November 2003 doc. : IEEE 802. 15 -03 -0460 -00 -0000 Conclusions • CSS has qualities of both spread spectrum and UWB. • CSS enhances robustness and range • CSS adds mobility • CSS can be implemented with today’s technologies • CSS is a global solution Submission 29 Lampe, Ianelli, Nanotron
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