march 2000 project: ieee p802.15 working group for

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:[[email protected]]

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


doc.: IEEE 802.15-00/083r0

Submission

Ultra-wideband RFA Tutorial

802 PlenaryAlbuquerque, NM

March 2000

March 2000


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


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


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


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


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


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


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


doc.: IEEE 802.15-00/083r0

Submission

More Multipath Images

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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


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

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doc.: IEEE 802.15-00/083r0

Submission

UWB Using Coherent Detection & Time Hopping

• Primary focus of Time Domain

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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


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


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


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

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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


doc.: IEEE 802.15-00/083r0

Submission

Time Modulated UWB Fuses 4 Functions

Convergence

Communication Radar

ImagingPositioning

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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


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


doc.: IEEE 802.15-00/083r0

Submission

Radar Demonstration

march 2000 project: ieee p802.15 working group for

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