Ultra-Wideband Tutorial Editors: Matthew Welborn and Kai Siwiak - - PDF document

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Ultra-Wideband Tutorial Editors: Matthew Welborn and Kai Siwiak - - PDF document

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<month year> doc.: IEEE 802.15-<doc#> March 2002 doc.: IEEE 802.15-02/133r1 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) etworks (WPANs) Project: IEEE P802.15 Working Group for Wireless Personal

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 1

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Project: IEEE P802.15 Working Group for Wireless Personal Area N Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) etworks (WPANs)

Submission Title: [Ultra-Wideband Tutorial] Date Submitted: [March 11, 2002] Source: [Matt Welborn] Company [XtremeSpectrum] Address [8133 Leesburg Pike, Suite 700, Vienna, VA 22182] Voice:[(703) 269-3052], FAX: [(703) 269-3092], E-Mail:[mwelborn@xtremespectrum.com] Source: [Kai Siwiak] Company [Time Domain] Address:[7057 Old Madison Pike, Huntsville, Al. 35806] Voice:[(256) 990-9062], FAX: [(256) 922-0387], E-Mail:[kai.siwiak@timedomain.com] Re: [N/A] Abstract: [This document is a Tutorial that describes the FCC’s first Report and Order on Ultra-Wideband

  • Technology. Preliminary details of the R&O are presented as well as background information on UWB
  • technology. ]

Purpose: [This Tutorial is intended to inform the membership on the UWB R&O and UWB in general.] 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 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 2

doc.: IEEE 802.15-02/133r1

Submission

Ultra-Wideband Tutorial

Editors: Matthew Welborn and Kai Siwiak

Reviewers: Bob Huang, Jeff Foerster, John McCorkle, and Michael Dydyk Sponsors: Sony, Intel, Siemens, Sharp Labs, TI, Motorola, IBM, Time Domain and XtremeSpectrum

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 3

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Ultra-Wideband Tutorial

  • Goal: To provide the 802 standards

committee with information about new developments in ultra-wideband technology

  • Roadmap

– New rules for UWB devices – History of UWB – Short introduction to UWB technology – Relevance to IEEE 802

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 4

doc.: IEEE 802.15-02/133r1

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FCC’s UWB Proceedings

  • Notice of Inquiry: September 1998
  • Notice of Proposed Rulemaking: May 2000

– Over 900 documents on record

  • Government, academic and commercial groups
  • Empirical and analytical studies
  • Characterized interaction mechanisms and measured thresholds

for impact of UWB signals on government and commercial systems

  • First UWB Report & Order: Adopted February 2002
  • Full text of the R&O is not yet released [as of 3/11/2002]
  • FCC has issued preliminary emission guidelines
  • NTIA has issued a summary analysis with emission and usage

recommendations

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 5

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Summary of the FCC Rules

  • Significant protection for sensitive systems

– GPS, Federal aviation systems, etc.

  • Lowest Limits Ever by FCC
  • Incorporates NTIA recommendations
  • Allows UWB technology to coexist with existing

radio services without causing interference

The R&O rules are “designed to ensure that existing and planned radio services, particularly safety services, are protected.”

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 6

doc.: IEEE 802.15-02/133r1

Submission

FCC UWB Device Classifications

  • R&O authorizes 5 classes of devices –

Different limits for each:

– Imaging Systems

  • 1. Ground penetrating radars, wall imaging, medical imaging
  • 2. Thru-wall Imaging & Surveillance Systems

– Communication and Measurement Systems

  • 3. Indoor Systems
  • 4. Outdoor Hand-held Systems

– Vehicular Radar Systems

  • 5. collision avoidance, improved airbag activation,

suspension systems, etc.

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 7

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Summary of Preliminary R&O Limits

Yes 1.99 to 10.6 GHz Through-wall and Surveillance No 24 to 29 GHz Vehicular No 3.1 to 10.6 GHz Communications (indoor & outdoor)* Yes 3.1 to 10.6 GHz (GPR <960 MHz) Imaging User Restrictions Frequency Band for Operation at Part 15 Limits Application *Indoor and outdoor communications devices have different

  • ut-of-band emission limits

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 8

doc.: IEEE 802.15-02/133r1

Submission 0.96 1.61 1.99 3.1 10.6 GPS Band

UWB Emission Limit for Indoor Systems

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 9

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Submission 0.96 1.61 1.99 3.1 10.6 GPS Band

UWB Emission Limit for Outdoor Hand-held Systems

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 10

doc.: IEEE 802.15-02/133r1

Submission

R&O is Ultra-Conservative Says FCC

  • R&O is described as a “cautious first

step” by the Commission

  • One commissioner describes the R&O

limits as “ultra-conservative” and “intentionally at the extreme end of what FCC engineers … believe necessary.”

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 11

doc.: IEEE 802.15-02/133r1

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History of UWB Technology

  • Before 1900: Wireless Began as UWB

– Large RF bandwidths, but did not take advantage of large spreading gain

  • 1900-40s: Wireless goes ‘tuned’

– Analog processing: filters, resonators – ‘Separation of services by wavelength’ – Era of wireless telephony begins: AM / SSB / FM – Commercial broadcasting matures, radar and signal processing

  • 1970-90s: Digital techniques applied to UWB

– Wide band impulse radar – Allows for realization of the HUGE available spreading gain

  • Now: UWB approved by FCC for commercialization

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 12

doc.: IEEE 802.15-02/133r1

Submission

What is UWB?

  • UWB signals are typically modulated pulse trains

– Very short pulse duration (<1 ns) – Uniform or non-uniform inter-pulse spacing

  • Pulse repetition frequency (PRF) can range from

hundreds of thousands to billions of pulses/second

  • Modulation techniques include pulse-position

modulation, binary phase-shift keying and others

Pulse width Inter-pulse spacing: uniform or variable

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March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 13

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Large Relative (and Absolute) Bandwidth

  • UWB is a form of extremely wide spread spectrum

where RF energy is spread over gigahertz of spectrum

– Wider than any narrowband system by orders of magnitude – Power seen by a narrowband system is a fraction of the total – UWB signals can be designed to look like imperceptible random noise to conventional radios

Narrow band (30kHz) Wideband CDMA (5 MHz) UWB (Several GHz) Frequency Part 15 Limit March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 14

doc.: IEEE 802.15-02/133r1

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Very Low Power Spectral Density (PSD)

  • FCC limits ensure that UWB emission levels are

exceedingly small

– At or below spurious emission limits for all radios – At or below unintentional emitter limits – Lowest limits ever applied by FCC to any system

  • Part 15 limits equate to –41.25 dBm/MHz

– For comparison, PSD limits for 2.4 GHz ISM and 5 GHz U- NII bands are 40+ dB higher per MHz

  • Total emissions over several gigahertz of bandwidth

are a small fraction of a milliwatt

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 15

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Large Fractional Bandwidth

  • Original FCC UWB definition (NPRM) is 25%
  • r more fractional bandwidth

– Fractional Bandwidth is the ratio of signal bandwidth (10 dB) to center frequency: Bf = B / FC = 2(Fh-Fl) / (Fh+Fl)

  • Preliminary FCC rules enable in excess of

100% fractional bandwidths

– 7.5 GHz maximum bandwidth at –10 dB points

  • Large fractional bandwidth leads to

– High processing gain – Multipath resolution and low signal fading

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 16

doc.: IEEE 802.15-02/133r1

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Scalable Technology with Low Power

  • UWB benefits from basic information theory

results when: Signal Bandwidth >> Data Rate

  • Power efficient low-order modulation can be

used even for relatively high data rates

  • Data rates can scale independent of PRF by

integrating bit intervals over multiple pulse intervals

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 17

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Multipath Performance

  • Ultra-wide bandwidth provides robust performance in

multipath environments

– Less severe signal fading due to multipath propagation means fade margin of only a few dB – Extremely short pulses enable resolution and constructive use of multipath energy using RAKE receiver techniques

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 18

doc.: IEEE 802.15-02/133r1

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Ranging and Imaging Capabilities

  • Many early applications of modern UWB

technology were in radar systems

  • Sub-nanosecond time resolution leads

to precision ranging and imaging capabilities

  • Capabilities result from the large relative

and coherent bandwidth

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 19

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UWB in Wireless Applications

  • Simple RF architectures

– No power amplifiers required – No IF filtering – Minimal off-chip components/low BOM

  • Low transmit power due to power-efficient

modulation techniques

  • Must handle strong narrowband interferers
  • Rich multipath environment

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 20

doc.: IEEE 802.15-02/133r1

Submission

Implications for Applications

  • UWB characteristics:

– Simultaneously low power, low cost high data-rate wireless communications – Attractive for high multipath environments

  • Enables the use of powerful RAKE receiver techniques
  • Low fading margin

– Excellent range-rate scalability

  • Especially promising for high rates ( >100 Mbps)
  • Candidate Applications:

– Wireless Video Projection, Image Transfer, High-speed Cable Replacement

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March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 21

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Challenges for UWB

  • Wide RF Bandwidth Implementation
  • In-Band Interference
  • Signal Processing Beyond Current DSP

(today requires analog processing)

  • Global Standardization
  • Broadband Non-resonant Antennas

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 22

doc.: IEEE 802.15-02/133r1

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Relevance to IEEE 802

  • UWB now has preliminary approval for

unlicensed use in the United States

  • UWB is complementary to other radio

technologies in existing 802 standards

– Potential to meet un-served application needs

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March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 23

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Appendix

  • Details of emission limits for UWB devices
  • Detailed results of coexistence analyses

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 24

doc.: IEEE 802.15-02/133r1

Submission 0.96 1.61 1.99 3.1 10.6

Operation is limited to law enforcement, fire and rescue organizations, scientific research institutions, commercial mining companies, and construction companies.

GPS Band

UWB Emission Limits for GPRs, Wall Imaging, & Medical Imaging Systems

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 25

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Submission 0.96 1.61 1.99 10.6

Operation is limited to law enforcement, fire and rescue organizations. Surveillance systems may also be operated by public utilities and industrial entities.

GPS Band

UWB Emission Limits for Thru-wall Imaging & Surveillance Systems

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 26

doc.: IEEE 802.15-02/133r1

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Regulations Insure Exceedingly Safe

  • Example - Effective Noise Figure of a 2dB NF GPS

– Assumes No Thermal Antenna Noise (antenna cannot see the earth) – Assumes all UWB devices transmitting simultaneously (but really TDMA) – All UWB devices 10m from GPS antenna

2 2.5 3 3.5 4 10 20 30 40 50 # of units dB

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 27

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In-door Aggregation Is Insignificant

WPAN # Range to Victim Receiver m Power received by Victim Receiver picowatt/MHz % of total energy received by victim receiver Accumulated Power Received By Victim Receiver Location of WPANs 1 3 0.029506 90.957 0.029506 Net in same room 2-18 7 0.001880 5.796 0.031386 17 Nets, 8 in adjacent rooms (left, right, above, below, left-above, right-above, left-below, right-below) PLUS 9 across the hall 19-50 11 0.000580 1.789 0.031966 32 Nets 16 in 2nd adjacent Rooms + 16 across hall 51-98 15 0.000252 0.776 0.032218 48 Nets, 24 in 3rd adjacet rooms + 24 across hall 99-162 19 0.000130 0.402 0.032348 64 Nets 32 in 4th adjacent rooms + 32 across hall 163-242 22 0.000091 0.280 0.032439 80 Nets 40 in 5th adjacent rooms + 40 across hall Total Interference = .032439 picowatts/MHz = -104.9 dBm/MHz =1.099 times the power from the closest emitter

  • By 4th ring, there are 64 simultaneous transmitters added at equal distance,

yet together they produce less the 1/2 percent of the total interference power

  • The tiny received noise does not increase without bound
  • The more distant WPANs become insignificant
  • i.e. In-building aggregation is insignificant

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 28

doc.: IEEE 802.15-02/133r1

Submission

In-door Aggregation Is Insignificant

  • Yes, Power adds Linearly
  • But…as the number of devices grows, the energy added becomes

insignificant

  • i.e. Aggregation effect is immaterial

0.9 0.92 0.94 0.96 0.98 1

20 40 60 80 100 120 140 160 180 200 220 240

Number of Devices Percent of Energy

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March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 29

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Outdoor Aggregation Is Insignificant

  • As height goes down

– Blockage by buildings tends to reduce the signal, but – The shorter path tends to increase the signal

  • Okumura-Hata propagation model
  • Antenna patterns

– GPS antenna: 0 dB at horizon, -10 dB straight down – UWB antenna: -2dB average

March 2002

Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 30

doc.: IEEE 802.15-02/133r1

Submission

Low Altitude Airborne GPS Safety Criteria Satisfied

  • City with 200 UWB devices per sq. km—aggregation is insignificant

– Emitter density from NTIA report – All devices transmitting simultaneously – All devices outside, no building attenuation – Plane passes over highest elevation UWB

  • Margin greater than 30dB

23 dB 34 dB below Thermal noise!

Hata R-Squared Thermal Noise

Airplane 28 meters above buildings (RTCA worst case)

  • 162
  • 157
  • 152
  • 147
  • 142
  • 137
  • 132
  • 127
  • 122
  • 117
  • 112

0.5 1 1.5 2

Distance Traveled (km) dBm/MHz

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Matt Welborn (XtremeSpectrum) and Kai Siwiak (Time Domain) Slide 31

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Submission

Higher Altitude Airborne GPS Safety Criteria Satisfied

  • City with 200 UWB devices per sq. km —aggregation is insignificant

– Emitter density from NTIA report – All devices transmitting simultaneously – All devices outside, no building attenuation – Plane directly over highest elevation UWB

  • Margin greater than 30 dB and increases with altitude

Hata R-Squared Thermal Noise

Noise Dies with Altitude Aggregation is immaterial

  • 160
  • 155
  • 150
  • 145
  • 140
  • 135
  • 130
  • 125
  • 120
  • 115

25 75 125 175 225 275

Height Above Buildings (m) dBm/MHz