UWB Applications and Technologies

Transcription

1 UWB Applications and Technologies Presentation for PersonalTelco Project Nathaniel August VTVT (Virginia Tech VLSI for Telecommunications) Group Department of Electrical and Computer Engineering Virginia Tech Blacksburg, VA 24061, USA March 31,

2 Overview Introduction History Definition Signaling Industry Activities IEEE Standardization Efforts 2

3 Virginia Tech 3

4 Definition In terms of bandwidth Ultra Wideband BW >> Wideband BW >> Narrowband BW Narrowband Power Spectral Density (db) Wideband UWB Frequency 4

5 History James Maxwell develops theory of EM waves: Maxwell s Equations 1870 Heinrich Hertz produces these waves and detects them Early wireless is UWB! Guglielmo Marconi applies EM waves for telegraphy

6 History Marconi and Hertz used spark gap transmissions Charge builds on the capacitor until the air is ionized Current briefly flows in the circuit Resulting transmission is a few cycles of a damped sinusoid Did not take advantage of ultra wide bandwidth Used mainly with Morse code and telegraphy The circuit produces a visible spark 6

7 History Narrowband transmitters appear 1900 Government regulates the spectrum and divides it into bands AM & FM radio, television appear Ionospheric propagation Wideband OFDM & CDMA Claude Shannon develops information theory 1950 Dark ages of narrowband 7

8 History Military investigates UWB for communications and radar 1950 MSSI Patents and publications on UWB Commercial products appear with FCC waiver UWB Renaissance FCC formally reserves spectrum for UWB

9 FCC Definition Ultra wideband fractional bandwidth is greater than 0.20 or absolute bandwidth is greater than 500 MHz or more. NB: (f H f L ) < 0.01*f C Power Spectral Density (db) -10dB UWB: (f H f L ) > 0.20*f C or (f H f L ) > 500 MHz f L f C Frequency (Hz) f H The FCC doesn t regulate the method to achieve the ultra wide bandwidth. 9

10 Typical UWB Emission Limits For indoor systems GPS band

11 UWB Advantages Wide bandwidth leads to dual capabilities High data rate communications High precision (sub-centimeter) radar Channel Capacity (Bits/sec) 14 x UWB C = B * log 2 ( Mbps SNR (db) SNR) NB Computed Bandwidths 1 MHz 10 MHz 20 MHz 30 MHz 40 MHz 50 MHz 60 MHz 70 MHz 80 MHz 90 MHz 100 MHz 200 MHz 500 MHz 1 GHz 11

12 UWB Advantages Overlays existing spectrum Like a freight train down a highway without any cars noticing Excellent immunity to interference from other radio systems or multipaths Extremely difficult to intercept wide spectrum and low-energy Low power and low cost Simple hardware structure; typically no carrier CMOS solution in near future Unlicensed for communications and measurement use 12

13 Applications High Resolution Radar and Sensing Vehicle radar See-through-the-walls (Police, fire, rescue) Ground penetrating radar Medical imaging Surveillance Wireless Communications Systems Home networking /PAN Roadside Info-station Short range radios Military communications Wireless sensor networks Location Finding Position location inventory RF ID Planetary exploration 13

14 UWB Signaling Design space ranges from Single, narrow pulses Multiple narrowband (continuous wave) signals I-UWB MC-UWB DS-CDMA MB-OFDM Proposed Solutions to a Single Signal Multiple Signals 14

15 Pulse Based Signaling 1 Gaussian monocycle in time domain 10 Gaussian monocycle in frequency domain Normalized amplitude τ=0.12 ns Normalized Spectrum [db] Time -90 f c =2.65 GHz Frequency (Hz) x 10 9 Single signal has better short range multipath immunity and more accurate ranging No carrier means low hardware complexity and low power Pulse shapes Gaussian, Hermetian Families 15

16 Modulation Types Binary Modulation: data Pulse Position Modulation (PPM) Pulse Amplitude Modulation (PAM) On Off Keying (OOK) Bi-phase Shift Keying (BPSK) 16

17 DS-UWB (CDMA) Signaling Pulses modulated onto a carrier The carrier is spread (multiplied) by a sequence of [+1, -1] More protection from interference Each spreading sequence is a channel Amplitude (V) DS-UWB Waveform PN Sequence Time (us) 17

18 Multicarrier Systems Several narrowband carriers Modulation just like narrowband systems Aggregate bandwidth is ultra wide by FCC s definition Ex: MB-OFDM f 0 f 1 f 2 f 3 f 4 f 5 One symbol duration 18

19 Industry Activity 19

20 Time Domain Corporation (TDC) Founded in 1987 Targets communications and location aware applications Patented PPM modulation Patented time hopping multiple access PulsOn chipset (SiGe) First commercial solution Received special FCC waiver for GHz operation 5 Mbps, 1-16 km range Initially targeted sub $200 handset market 20

21 Copyright 2004 VTVT Lab, Virginia Tech MultiSpectral Solutions Inc. (MSSI) Founded in 1989 Most product consist of COTS components Wireless technology for communications Precision asset location systems Micro air vehicle obstacle/collision avoidance system UWB intrusion detection system for long range perimeter surveillance * Communications Asset Location Collision Avoidance 21

22 Intel Developed a channel model Investigated feasibility for CMOS integration Wireless USB supports the processor Backs MB-OFDM approach for a Achieved 100 Mbps (Feb. 28, 2002) 22

23 Xtreme Spectrum Inc. (XSI) Founded in 1998, bought by Motorola in fall 2003 Targets home networking Patented bi-phase modulation Backs DS-CDMA approach for a Trinity chipset First FCC compliant commercial system SiGe technology GHz range Demonstrated 100 Mbps system Uses MAC < 200 mw total power 23

24 Standardization Activities 24

25 UWB Standardization Efforts IEEE a high data rate communications IEEE a low data rate communications and radar (everything else) 25

26 IEEE a 26

27 IEEE /3a IEEE is an existing standard for WPANs Defines MAC layer and Bluetooth PHY layer IEEE a proposes UWB PHY Proposed applications Replacement of high speed cable at home: Multi-cluster home network (XtremeSpectrum Inc.) Wireless peripheral at future office: Wireless USB (Intel) Wearable peripheral for CE (consumer equipment), health, or fashion of human beings (General Atomics) 27

28 WPAN Applications Future home/office multi-cluster network Home Office Cluster (infrastructure) UMPW HUB USB Cluster (ad-hoc) Kids room Cluster (ad-hoc or infrastructure-based) 1394 Home Entertainment Cluster (infrastructurebased) Gateway (OSGi) Backbone Wired Backbone (HPNA, HomePlug, Ethernet, ) or a wireless Bridge (54-108Mbps) Reference: P a 02/031r0 CFA

29 Multiband OFDM PHY Proposal Has largest industry backing - Intel and TI are major backers No silicon yet Not much different than a or g Input Data Modulation Serial to Parallel. IFFT. Parallel to Serial To RF OFDM System 29

30 Multiband OFDM PHY Proposal 528 MHz bands with 128 narrowband tones Bands grouped into 4 distinct groups GROUP A GROUP B GROUP C GROUP D Band #1 Band #2 Band #3 Band #4 Band #5 Band #6 Band #7 Band #8 Band #9 Band #10 Band #11 Band #12 Band # MHz 3960 MHz 4488 MHz 5016 MHz 5808 MHz 6336 MHz 6864 MHz 7392 MHz 7920 MHz 8448 MHz 8976 MHz 9504 MHz 9.5 ns Guard Time Cyclic Prefix 60.6 ns MHz f Frequency (MHz) ns ns Information Time #1 #2 #3 30 Period=937.5 ns

31 DS-CDMA PHY Proposal Backed by Motorola/XtremeSpectrum Successfully demonstrated similar technology Low Band 25 to 400 Mbps High Band 25 to 900 Mbps Multi-Band Up to 1.35 Gbps db GHz db GHz db GHz Long Wavelet Mid Wavelet Duplex Wavelet

32 Multiband OFDM vs. DS-CDMA Interferences to others MB-OFDM worse than AWGN or DS-CDMA at same power Fading MB-OFDM has deep fade effect compared with DS-CDMA Multipath Energy collection MB-OFDM collects channel energy due to narrow tones DS-CDMA uses rake receiver Performance MB-OFDM maintains rate over longer range DS-CDMA has higher data rate / lower power at short range DS-CDMA has more accurate ranging ability 32

33 Current Status Deadlocked since last summer Motorola brought a new proposal to last week s meeting Motorola also promoted a 2 PHY solution using common signaling MB-OFDM is developing their own MAC outside of IEEE DS-CDMA Deadlock MB-OFDM 33

34 IEEE a 34

35 IEEE a Applications Location aware applications Locating people firefighter rescue, identify friendly soldier s locations, track children Locating and tagging assets autonomous manifesting for shipping, inventory control for warehouses, RFID, supply chain management Smart homes open doors, find keys, manage TV, radio, computers for individual preferences as individuals move throughout a home Densely packed environments Real time tracking of assets on pallets in trucks or ships Wire replacement for remote sensors in industrial settings Sensor networks 35

36 IEEE a Criteria Full criteria release in May 2004 Current requirements Low data rate (1 Kbps - 10 Kbps) Support for 1000s of nodes Mesh networking Mandatory location awareness Mandatory support for mobility Max range of 30 m, more for asset tracking Power less than 1 mw operate for years on battery life or energy scavenging Proposals accepted after May

37 Research at Virginia Tech CMOS UWB radio implementation Channel measurement and modeling Accurate ranging for asset location Energy efficient UWB radios for wireless ad hoc and sensor networks MAC protocols LNA Frequency Domain Sampler Filter f 0 Filter f 1 Filter f n 1 ADCs Energy Detector 0 Energy Detector 1 Energy Detector n-1 Energy Harvester Multipath Resolving Threshold and Combine Pulse Sense Block Frequency Domain Correlator Template Constructor Pulse Sense Decision Block 37

38 Summary UWB characteristics Low power License free World wide availability Can trade high data rate for distance Dual communication and radar capability Standardization efforts a MAC has been approved, while PHY is still being deliberated a PHY has yet to be defined Future trends UWB offers great potentials for home networking, wireless sensors, and location aware systems. 38