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

March 2002

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

doc.: IEEE 802.15-02/133r0

Submission

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

Submission Title: [Ultra-Wideband Tutorial]Date Submitted: [March 8, 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:[[email protected]]Source: [Kai Siwiak] Company [Time Domain]Address:[7057 Old Madison Pike, Huntsville, Al. 35806]Voice:[(256) 990-9062], FAX: [(256) 922-0387], E-Mail:[[email protected]]

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


doc.: IEEE 802.15-02/133r0

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

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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


doc.: IEEE 802.15-02/133r0

Submission

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

• UWB Report and Order: Adopted February 2002• Full text of the R&O is not yet released [as of 3/7/2002]• FCC has issued preliminary emission guidelines• NTIA has issued a summary analysis with emission and usage

recommendations

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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


doc.: IEEE 802.15-02/133r0

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 imaging2. 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.

March 2002


doc.: IEEE 802.15-02/133r0

Submission

Summary of Preliminary R&O Limits

Application Frequency Band for Operation at Part 15

Limits

User Restrictions

Imaging 3.1 to 10.6 GHz

(GPR <960 MHz)

Yes

Through-wall and Surveillance

1.99 to 10.6 GHz Yes

Communications (indoor & outdoor)*

3.1 to 10.6 GHz No

Vehicular 24 to 29 GHz No

*Indoor and outdoor communications devices have different out-of-band emission limits

March 2002


doc.: IEEE 802.15-02/133r0

Submission

UWB Coexistence Analysis

• All classifications of devices provide significant protection below Part 15 levels for GPS and other out-of-band systems– Unrestricted systems provide an extra 34 dB protection for

all GPS bands in addition to Part 15 limits

– Aggregate effects of distant UWB devices found to be insignificant

• UWB technology previously proposed for IEEE 802.15.3 demonstrated excellent coexistence with other 802 systems – See document 00195r8P802-15_TG3

March 2002


doc.: IEEE 802.15-02/133r0

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.”

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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


doc.: IEEE 802.15-02/133r0

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

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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

Narrowband (30kHz)

Wideband CDMA (5 MHz)

UWB (Several GHz)

Frequency

Part 15 Limit

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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

March 2002


doc.: IEEE 802.15-02/133r0

Submission

Large Fractional Bandwidth

• Original FCC UWB definition (NPRM) is 25% or 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


doc.: IEEE 802.15-02/133r0

Submission

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

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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


doc.: IEEE 802.15-02/133r0

Submission

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

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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


doc.: IEEE 802.15-02/133r0

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

March 2002


doc.: IEEE 802.15-02/133r0

Submission

Relevance to IEEE 802

• UWB is now approved for unlicensed use

• UWB is complementary to other radio technologies in existing 802 standards

– Potential to meet un-served application needs

• Exceptional coexistence properties with other unlicensed band technologies

March 2002


doc.: IEEE 802.15-02/133r0

Submission

IEEE 802.15 Study Group 3a

• 802.15.3 has created a Study Group to investigate the creation of an alternate PHY to address higher data rate applications

• Development of a higher rate PHY in IEEE provides opportunity to ensure coexistence with other 802 systems

• Currently reviewing Application Presentations and developing requirements documents

– Presentations indicate a need for > 100 Mbps data rates

• UWB is an ideal candidate for high-rate WPAN applications

– Relatively short range (FCC limits) and high data rates

– Possible addition of location awareness capability

– SG3a is open to other PHY technologies as well

March 2002


doc.: IEEE 802.15-02/133r0

Submission

Summary

• FCC Ruling allows UWB devices

• UWB devices co-exist well with other systems

– Can be on same device with GPS, PCS, 802.11

• UWB devices have inherent benefits for high data-rate in high-clutter applications

March 2002


doc.: IEEE 802.15-02/133r0

Submission

Appendix

• Details of emission limits for UWB devices

• Detailed results of coexistence analyses

March 2002


doc.: IEEE 802.15-02/133r0

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

March 2002


doc.: IEEE 802.15-02/133r0

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


doc.: IEEE 802.15-02/133r0

Submission

0.96 1.61

1.99

3.1 10.6

GPS Band

UWB Emission Limit for Indoor Systems

March 2002


doc.: IEEE 802.15-02/133r0

Submission

0.96 1.61

1.99

3.1 10.6

GPS Band

UWB Emission Limit for Outdoor Hand-held Systems

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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

0 10 20 30 40 50# of units

dB

March 2002


doc.: IEEE 802.15-02/133r0

Submission

In-door Aggregation Is InsignificantWPAN

#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 hall51-98 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 hall163-242 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


doc.: IEEE 802.15-02/133r0

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

0 20 40 60 80 100 120 140 160 180 200 220 240

Number of Devices

Per

cent

of

Ene

rgy

March 2002


doc.: IEEE 802.15-02/133r0

Submission

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


doc.: IEEE 802.15-02/133r0

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 0.5 1 1.5 2Distance Traveled (km)

dB

m/M

Hz

March 2002


doc.: IEEE 802.15-02/133r0

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 AltitudeAggregation is immaterial

-160

-155

-150

-145

-140

-135

-130

-125

-120

-115

25 75 125 175 225 275Height Above Buildings (m)

dB

m/M

Hz

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

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