UWB Radio: A Music Lesson

Transcription

1 / t TimeDerivative UWB Radio: A Music Lesson based on: Kazimierz Siwiak and Debra McKeown, Ultra-Wideband Radio Technology, UK: Wiley and Sons, 2004 and featuring the cartoon artistry of Nairobi s Gammz presented to: IEEE Communications Society 19, San Francisco, CA / t TimeDerivative TimeDerivative Inc NW 14th Street Coral Springs, FL Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 1

2 UWB Radio Technology Kai Siwiak and Debra McKeown Based on, Ultra-wideband Radio Technology, UK: Wiley, 2004, authors Siwiak and McKeown trace UWB technology through history, regulations, standards, system implementations and commercial applications. There has been a recent surge of invention and commercialization interest following the FCC s Report and Order which provides for unprecedented access to more than 7.5 GHz of unlicensed UWB spectrum in the US. Methods of generating and modulating UWB signals are described and set in the context of IEEE802 Standards. The future of UWB is a judicious mix of wireless communications at data bandwidths exceeding a Gigabit per second, and precision positioning and radar. Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 2

3 Contents Where did UWB come from? Basic Wireless Concepts A History of Wireless and UWB Radio Regulations Shape the EM Spectrum How will UWB appear in the market place? Wireless Standards? UWB Signal Generation and Modulation How does it perform and what does UWB do? Applications Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 3

4 Separation of Signals Conventional signals discerned one from the other by unique location in the spectrum Ideal smallest bandwidth occupancy Best capacity is when each user occupies the smallest sliver of bandwidth - the sine wave carrier, a pure tone! [McKeown 2003] Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 4

5 A sinusoidal waveform occupies an impulse in frequency, forever T forever forever time this occupies this spectrum forever [McKeown 2003] f 0 =1/T frequency... C C# D D# E F... Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 5

6 Separation by Frequency T1 T2 T3 time time time these occupy this spectrum, forever f 0 =1/T1 f 0 =1/T2 f 0 =1/T3... C C# D D# E F... frequency Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 6

7 Narrow Band: Separation by Frequency T1 T2 T3 time time time these occupy this spectrum, forever [McKeown 2003] Like a noisy audience! f 0 =1/T1 f 0 =1/T2 f 0 =1/T3 frequency Tones are not pure... contain noise, harmonics, etc. In radio, there is a level for these un-intentional emissions Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 7

8 The shorter a signal is in time, the wider its spectrum is in frequency, for that duration in time T time this occupies this spectrum for time T f=0 f 0 =1/T frequency f=2/t Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 8

9 An impulse in time, like a drum hit, occupies an indefinitely wide spectrum in frequency, for an instant in time time this occupies this spectrum for an instant [McKeown 2003] forever forever frequency Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 9

10 Separation of Signals: another look Signals can be separated in time Ideal now is the shortest duration Best capacity is when each user occupies the smallest sliver of time - impulse radio! so: narrow bandwidth is not the only way to go! narrow time can work also! Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 10

11 Separation of Signals in Time t 1 t 2 t 3 t 4 time these occupy this spectrum, each for an instant at t 1 at t 2 at t 3 at t 4 frequency Both tones and impulses convey information simultaneously The drum energy stays below the un-intentional emission levels Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 11

12 A Short History of UWB Wireless Started in the era of Hertz and Marconi Earliest transmit experiment were UWB Now way at the time to efficiently receive the signals Technology went narrow band ( tones ) Easiest way to separate multiple users at that time Without digital technology it is difficult to separate the different drummers Benefits of wider bandwidth radio soon realized Wide band FM for high fidelity audio: trade DSSS/CDMA for efficient cell phone capacity Trend complete with UWB regulations Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 12

13 Wireless Began as UWB Led to Morse telegraphy (25wpm=20 Hz BW) No way to take advantage of HUGE bandwidth spreading gain! 1870s Hertzian experiments were UWB Apparatus was spark gap Low-Q circuits Large RF bandwidths 1890s Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 13

14 Wireless Becomes NB Radio Government Radio Regulations 1912 Separation of services by wavelength Spark outlawed 1900s Wireless goes tuned Analog processing: filters, resonators 1920s Wireless becomes radio Era of wireless telephony begins AM / SSB Ionospheric propagation developed FM modulation introduced s Commercial Broadcasting matures Radar and signal processing Wide band radar Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 14

15 The Mantra of Narrow Band Challenged Ideal (enforced by regulations in 1912) Use only the bandwidth needed by the information Separation of signals by wavelength (by tone) But: Bandwidth can be traded for performance Wide band FM known for its superior audio fidelity better SNR in a noisy channel The Mantra of narrow band challenged for the first time Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 15

16 UWB Reappears UWB-like Patents 1960s Patents begin appearing using UWBlike techniques CDMA 1980s CDMA appears in mobile phones UWB gets its name:1989 DoD 1940s Claude Shannon, Heddy Lamarr Papers refer to the down in the noise as most efficient communication Frequency hopping spread spectrum 1950s UWB and impulse technology Both heavily investigated for communications, radar & other applications 1970s Digital applied Digital techniques applied to UWB impulse radios Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 16

17 Wide Band is Better! Introduction of Direct Sequence Spread Spectrum (IS-95): NB mantra challenged a second time Regulator allocates a block of frequencies Users each occupy all of the bandwidth Superior spectral efficiency! many different drummers can coexist their drum beats encode special sequences digital techniques can efficiently differentiate among them Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 17

18 UWB in the Mainstream Æther Wire & Location, Inc. FCC Approval 2002 UWB approved by FCC for commercialization 1990s Commercial system First commercial systems emerging (thanks to device technology) Commercial Deployment the rush to the market place? 2003 Standards Widespread interest Standards under construction Several FCC certified devices appear Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 18

19 UWB: Widest is Best! Possible to re-use spectrum occupied by other users Levels set at the unintentional emission limit Superior spectral efficiency! Drums and Tunes coexist The NB mantra challenged a third time [McKeown 2003] Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 19

20 UWB Definitions UWB ultra-wideband, first used ~1989 by the U.S. Department of Defense, replaced terms like baseband, carrier-free or impulse used through the 1980's UWB bandwidth [see: US FCC Sec (a)] is the frequency band bounded by the points that are 10 db below the highest radiated emission, as based on the complete transmission system including the antenna UWB impulse [ITU-R TG1/8] a unipolar signal having a time duration equal to the reciprocal of the UWB bandwidth UWB pulse [ITU-R TG1/8] an emitted signal having a time duration equal to the reciprocal of the UWB bandwidth Burst [ITU-R TG1/8] an emitted signal having a time duration not related to the UWB bandwidth Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 20

21 Access Rules to UWB Spectrum The UWB BW is contained within 3.1 to 10.6 GHz (Hand held systems) tuned drums Maximum EIRP Spectral Density of: dbm/mhz UWB transmitter signal BW is defined: as lesser of 20% fractional BW or 500 MHz same level as un-intentional emissions FCC does not define signal or modulation can use tuned drums, or chords, or both Source: US 47 CFR Part15 Ultra-Wideband Operations FCC Report and Order, 22 April 2002: Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 21

22 Actual UWB Emission Mask for Hand-held Systems EIRP, dbm/bw -40 Subpart C Part Quasi-peak detector, 120 khz BW handheld Subpart F 1 ms average in 1 MHz BW vehicular radar [McKeown 2003] Most UWB systems will be introduced in: GHz Frequency, GHz See: FCC First Report and Order, April 22, 2002 and latest US 47 CFR Part 15 UWB Bandwidth must be contained in: GHz Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 22

23 Many Winning UWB Technologies DS-UWB MB-OFDM Technology Proponents BW Access direct sequence ultrawide band orthogonal frequency division multiplexing Freescale / UWB Forum / Pulse~LINK MBOA-SIG UWB pulse 122 narrow band carriers MB-Impulses multi-band impulses General Atomics UWB pulse TM-UWB time-modulated ultrawide band Time Domain Corporation DSD direct sequence doublets Æther Wire & Location TDR-UWB others? transmitted delayedreference ultra-wide band General Electric Corporate Research UWB pulse UWB impulse pairs UWB pulse pairs 2nd Report and Order: rules refined, restrictions loosened! Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 23

24 UWB Signal Design Basics Width of pulse defines the bandwidth, and hence total EIRP Cycles per pulse defines center frequency Envelope defines the energy structure outside the main lobe Other, more complex pulses possible, other signals possible! FCC: Minimum BW above 2.5 GHz is 500 MHz so we can use narrow band technologies (aggregation of narrow band signals: OFDM) Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 24

25 A UWB Pulse Transmitter clock generator center frequency f c h sin(θ) H φ (r, t) = I 4πrc z (t) t frequency synthesizer t data clock pulse shaper antenna radiated UWB pulses input data data buffer t pulses at f C base band data impulses t t shaped base band data impulses Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 25

26 What about Standards? The Infoplease A-Z Dictionary < defines Standard as: something considered by an authority or by general consent as a basis of comparison; an approved model a grade of beef immediately below good [McKeown 2003] A Standards Engineer codifies well-understood phenomena and applies them to well-known problems The nice thing about standards is that there are so many to choose from Andrew S. Tannenbaum Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 26

27 IEEE 802 Organization LAN/MAN Standards Committee (Wireless Areas) WLAN IEEE WPAN IEEE WMAN IEEE MBWA IEEE Bluetooth Coexistence Zigbee 2.4 GHz High Data Rate MAC & 2.4 GHz PHY Task Group 4a pulse UWB Regulatory TAG IEEE Coexistence TAG IEEE Task Group 3a DS-UWB and MB-OFDM Mini-Glossary: WLAN-wireless Local Area Network; MAN-Metropolitan Area Network; TAG-Technical Advisory Group;-MBWA-Mobile Broadband Wireless Access Based on: Overview of and 3a, R. F. Heile, Workshop on Current Developments in UWB, Institute for Infocomm Research, Singapore Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 27

28 Where Do the Many UWB Winners Fit? Usage Scenario WPAN WLAN WMAN ZigBee Ultra-Wideband Bluetooth G/2.5G/3G Cellular [McKeown 2003] ,000 Data Rate (Mbps) After: Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 28

29 What does UWB bring? CAPACITY! C, Link capacity Mb/s 100,000 10,000 2,700 1,000 ofdm path loss model: [Equ (6.26) with d 1 =12 and γ=3] C=B log 2 (1+snr) UWB limit: FCC, Shannon, Boltzmann, perfect rake UWB 1.5 GHz BW, *15 db NF+IL+e b, rate 1/2 FEC interesting areas Range, m GHz 9 dbm, *25dB NF+IL+e b, 8% FER Bluetooth 2.45 GHz 0 dbm, FSK: *42 db NF+IL+e b GHz 0 dbm, *35dB NF+IL+e b, 1% PER *Apples and Oranges comparison? Different NF+IL+e b budgets in specs! Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 29

30 Economics of UWB Net benefits to economy Costs imposed on economy Net value to the economic entity Quality Cost Deployment UWB relative to alternatives; enabler for new services new capabilities 2G, 3G, 4G Fix Satellite Fixed microwave Interference with incumbent services WAN, LAN, PAN GPS Aviation Military + or -? How large? When? Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 30

31 Why UWB? Economic Benefits! Costs $$$ Benefits xx time Net value to economy Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 31

32 UWB Consumer Electronics Applications Courtesy of: Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 32

33 PC-centric View: Wireless USB Courtesy of Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 33

34 Mobile-centric View: DS-UWB Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 34

35 The Need for Speed? Why do we need such high speeds? 1 Full-length, HD Quality Movie with surround sound can be +40 Gb At Bluetooth rates, 1 file transfer can take 20 hours At WiFi 11b rates, the same file transfer can take 4 hours At WiFi 11a/g rates, it is still 45 minutes With UWB at 114 Mbps, it is only 9 minutes At 1 Gbps, it s just 1 minute! The limit of human visual perception is Gbps Bill Glenn, FAU [McKeown 2003] Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 35

36 Summary Wireless and its History started as UWB created spectral mess separation by wavelength Regulations Shape the EM Spectrum channelization wide band makes inroads Wireless Standards codify UWB systems on the verge of acceptance/deployment Applications Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 36

37 Questions? Discussions? Answers? About the... Technology Regulations Standards The Players Applications?? Copyright Kazimierz Siwiak and Debra McKeown, All Rights Reserved 37