march 2000 project: ieee p802.15 working group for
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March 2000
Paul Withington, Time DomainSlide 1
doc.: IEEE 802.15-00/083r0
Submission
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Project: IEEE P802.15 Working Group for Wireless Personal Area NProject: IEEE P802.15 Working Group for Wireless Personal Area Networks (etworks (WPANsWPANs))
Submission Title: [Ultra-wideband RF-A Tutorial]Date Submitted: [March 6,2000]Source: [Paul Withington] Company [Time Domain]Address [Add address Street, City, PC, Province/State, Country]Voice:[256 922 9229], FAX: [Add FAX number], E-Mail:[paul.withington@tdsi.com]
Re: [UltraWideBand tutorial for 802.][If this is a response to a Call for Contributions, cite the name and date of the Call for Contributions to which this document responds, as well as the relevant item number in the Call for Contributions.][Note: Contributions that are not responsive to this section of the template, and contributions which donot address the topic under which they are submitted, may be refused or consigned to the “General Contributions” area.]
Abstract: [Presentation on Ultra Wide Band RF]
Purpose: [Tutorial #1, March 6, 2000.]
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.
March 2000
Paul Withington, Time DomainSlide 2
doc.: IEEE 802.15-00/083r0
Submission
Ultra-wideband RFA Tutorial
802 PlenaryAlbuquerque, NM
March 2000
March 2000
Paul Withington, Time DomainSlide 3
doc.: IEEE 802.15-00/083r0
Submission
Who’s Presenting?
• Paul Withington• Time Domain Corp.
– Communications– Radar– Precision positioning & tracking
• Members of the Ultra-Wideband Working Group (www.uwb.org)
• We don’t represent the whole industry…
March 2000
Paul Withington, Time DomainSlide 4
doc.: IEEE 802.15-00/083r0
Submission
What is UWB?
• Definition– Fractional Bandwidth ≥ 25%– Where:
– Source:• “Assessment of Ultra-Wideband (UWB) Technology”,
OSD/DARPA Ultra-Wideband Radar Review Panel, R-6280, Defense Advanced Research Projects Agency (July 13, 1990)
• See also Introduction to Ultra-Wideband Radar Systems, James D. Taylor, ed., CRC Press, at p. 2 (1995)
)(
)(2 BandwidthFractional
LH
LH
ff
ff
+−
=
March 2000
Paul Withington, Time DomainSlide 5
doc.: IEEE 802.15-00/083r0
Submission
Rationale
• Achieving linearity is often difficult much beyond 10% relative bandwidth making non-traditional approaches more attractive
• Special characteristics of waveforms with small number of zero crossings become increasingly evident
March 2000
Paul Withington, Time DomainSlide 6
doc.: IEEE 802.15-00/083r0
Submission
Why Use UWB?
• Promise of processing gain– Anti-jam (anti-multipath)– Anti-clutter
• Promise of hardware simplicity– Avoidance of high chip rate modulation – Time domain signal processing
• Potential to fuse functionality– Communications– Positioning– Sensing
March 2000
Paul Withington, Time DomainSlide 7
doc.: IEEE 802.15-00/083r0
Submission
Marketplace Interest
• Office of Naval Research has requested proposals for 802.11 “compliant” UWB systems– Security– Reduction in emissions detectability– Performance within ships & submarines– Standard interface
March 2000
Paul Withington, Time DomainSlide 8
doc.: IEEE 802.15-00/083r0
Submission
Multipath Advantage
• RAYLEIGH FADING : A Continuous Wave PhenomenonConventional Radios Overcome Fading with PowerHigh Power Transmitter are Detectable and Consumed Batteries
• TM-UWB Does Not Use Continuous WavesNo Rayleigh fadingNo high power transmission required to overcome Rayleigh fading
Direct Path
Path 2
Path 1Dire
ct Pat
h
Path 2
Path 1
Interfering
ReceiveWindow(500 ps)
• •
Non-Interfering
March 2000
Paul Withington, Time DomainSlide 9
doc.: IEEE 802.15-00/083r0
Submission
Multipath Advantage
Unobstructed 10 meter LOS Path Obstructed 8 meter Path
Bas
eban
dA
mpl
itue
Bas
eban
dA
mpl
itue
Time (ns) Time (ns)
March 2000
Paul Withington, Time DomainSlide 10
doc.: IEEE 802.15-00/083r0
Submission
More Multipath Images
March 2000
Paul Withington, Time DomainSlide 11
doc.: IEEE 802.15-00/083r0
Submission
Lower vs. Higher Frequencies
• Higher Frequencies Do Not Propagate as Effectively as Lower Frequencies
• Extremely Expensive to Create Sufficient Bandwidth with Narrowband CW Techniques
Source: L. M. Frazier, Hughes, SPIE
Frequency (GHz)3 5 8 10 20 30 50 80 100 200
35
30
25
20
15
10
5
0
Concrete Block Painted 2X6 Board
Clay Brick
3/4" Plywood
3/4" Pine Board
Wet Paper TowelGlassDrywall
Asphalt Shingle
To
tal O
ne
Way
Att
enu
atio
n (
dB
)
Kevlar SheetPolyethylenePaper Towel (Dry)Fiberglass Insul.
March 2000
Paul Withington, Time DomainSlide 12
doc.: IEEE 802.15-00/083r0
Submission
Some UWB History
• Ross – Radar for ship docking at Sperry– Formed ANRO
• Ground Penetrating Radar companies formed• Big pulse work• Fullerton issued communications systems
patents in mid-80’s & forms Time Domain• 1990’s rapid acceleration of UWB R&D
March 2000
Paul Withington, Time DomainSlide 13
doc.: IEEE 802.15-00/083r0
Submission
UWB Using Coherent Detection & Time Hopping
• Primary focus of Time Domain
March 2000
Paul Withington, Time DomainSlide 14
doc.: IEEE 802.15-00/083r0
Submission
Technical Characteristics• Extremely large RF bandwidths
– High performance communications– Precision distance measuring
– High resolution radar
• Maximum performance – Coherent Matched Filter Correlating Receiver
– Minimize transmitted power
• Minimial signal profile– Minimize pulse amplitude (high PRF=small pulses)
– Noise-like Signal (LPI/D)
March 2000
Paul Withington, Time DomainSlide 15
doc.: IEEE 802.15-00/083r0
Submission
Time Modulated Ultra-Wideband
• Not a sinewave, but millions of pulses per second
• Time coded to make noise-like
• Pulse position modulation
500 ps
Time
Randomized Time Coding
Am
plit
ude
δδ δδ
δ = 125 = 125 ps
“0” “1”
Pow
er S
pect
ral D
ensi
ty (
dB)
-80
-40
0
Frequency (GHz)1 2 3 4 5
Frequency (GHz)
Random noise signal
March 2000
Paul Withington, Time DomainSlide 16
doc.: IEEE 802.15-00/083r0
Submission
Cross Correlation Filtering• An analog process
– Linear multiplication– Integration
RF Signal
TemplateWaveform Time
Output of Multiplier /Input to Integrator
Time
Output of Integrator
∫
March 2000
Paul Withington, Time DomainSlide 17
doc.: IEEE 802.15-00/083r0
Submission
Coherent Pulse Integration• TM-UWB does not send one symbol per
pulse• TM-UWB depends on coherent pulse
integration for additional processing gain– For a 2 GHz fc 10 Mpps system transmitting 1
mbps, one symbol is spread over 10 pulses– 10 Log (10) = 10 dB additional processing gain
• Total processing gain– Duty cycle gain + pulse integration gain– 23 dB + 10 dB = 33 dB
• Vary bit rate by changing pulse integration gain
March 2000
Paul Withington, Time DomainSlide 18
doc.: IEEE 802.15-00/083r0
Submission
Rake Receiver Performance
10 20 30 40 50 60 7060
70
80
90
100
110
120
Range (feet)
Am
plitu
de (
dB)
P ower in Top 10 Corre lations vs Range
+ Rake Combined Performance+ Rake Combined Performance
Power In Top 10 Pulses
• Five walls• Non-LOS• 6 dB rake gain
in building
March 2000
Paul Withington, Time DomainSlide 19
doc.: IEEE 802.15-00/083r0
Submission
Time Modulated UWB Fuses 4 Functions
Convergence
Communication Radar
ImagingPositioning
March 2000
Paul Withington, Time DomainSlide 20
doc.: IEEE 802.15-00/083r0
Submission
Chip Set Status
• 1st Generation SiGe chips– Synchronous programmable
time delay• 3 ps resolution
– Multiple correlator ASIC• 80 to 90 db dynamic range• -93 to –95 dBm sensitivity
• Third chip (in development)– DSP/controller is necessary for
signal processing and system control
– Standard CMOS
• 2nd Generation SiGe chips in design
March 2000
Paul Withington, Time DomainSlide 21
doc.: IEEE 802.15-00/083r0
Submission
Resources
• www.uwb.org• Reading:
– Introduction to Ultra-Wideband Radar Systems, James D. Taylor, ed., CRC Press, at p. 2 (1995)
– “Multiple Access with Time-Hopping Impulse Modulation”, R.A. Scholtz, Invited Paper, IEEE Milcom’93, Boston, MA, October 11 – 14, 1993.
– “On the Robustness of Ultra-Wide Bandwidth Signals in Dense Multipath Environments”, M.Z. Win & R.A. Scholtz, IEEE Communications Letters, Vol. 2, No. 2. February, 1998.
March 2000
Paul Withington, Time DomainSlide 22
doc.: IEEE 802.15-00/083r0
Submission
Radar Demonstration
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