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May, 2001TIME DOMAIN®
UWB Technology
Michal Freedhoff, Ph.D.
Director of Regulatory Policy
May, 2001TIME DOMAIN®
What Is Ultra-Wideband?
A wireless technology that uses ultra-low power (microwatts) to deliver megabits across multiple gigahertz
It can fuse high performance communications with precision location and high resolution radar sensing
May, 2001TIME DOMAIN®
What Is Ultra-Wideband?
Definition
At Part 15 powers (a few tens of microwatts total - across several GHz), cannot be reliably measured below 10 dB down points
UWB signals at higher center frequencies will have larger bandwidths
fu-flfu+fl
2 0.25
Where: fu= upper 10 dB down point fl = lower 10 dB down point
May, 2001TIME DOMAIN®
Time Modulated Ultra-Wideband
Not a sinewave, but millions of pulses per second
Time coded to make noise-like
Channelization Anti-jam Smooths spectrum
Pulse position modulation
500 ps
Time
Randomized Time CodingA
mpl
itud
e
ps
“0” “1”
Pow
er S
pec
tral
Den
sity
(d
B)
-80
-40
0
Frequency (GHz)1 2 3 4 5
Frequency (GHz)
Random noise signal
May, 2001TIME DOMAIN®
Time Domain UWB –Three Technologies in One
Enables vast improvements Wireless
communications Precision tracking Radar sensing
PulsON, A Chip Based Solution
May, 2001TIME DOMAIN®
Save and Protect Lives Victims of crimes and disaster Police, fire, rescue personnel Workplace, environmental and highway safety Military and civilian security
Independent Living/Better Health Care Aged and disabled independence Diagnosis and treatment Lower costs
“Digital Divide” relief Lower cost indoor broadband
Complement and Extend Reach of GPS Aviation safety
Worldwide Race - Breakthrough Technology Jobs/Economic Development Global Technology Leadership Relieve “spectrum drought”
Unique Benefits of UWB
May, 2001TIME DOMAIN®
POTS
CATV
MMDS
Satellite
Optical DSL
Cable Modem
FTTH
Broadband To The Home...
The Challenge: “Broadband Thru The Home”
What is UWB’s Role in the Future of Broadband
Wireless
May, 2001TIME DOMAIN®
TM-UWB Enables… In-Building 3-D Precision Location & Tracking
(indoors +/- 3 cm)
Proposed TimeTagTM
Design for Precision Tracking
People Tracking – DOC SBIR to track firefighters– DOD to track soldiers in urban training scenarios
Asset Tracking – Partnership with GE and grant from NIST to track medical equipment in hospitals
May, 2001TIME DOMAIN®
Radar Prototype
Waiver from FCC to sell a limited number of Radarvision devices
Through wall motion sensing for law enforcement, and
earthquake rescue
May, 2001TIME DOMAIN®
Unlicensed Spectrum
1 2 3 4 5 6
Pow
er
Frequency (GHz)
Part 15
2.4 GHz UNII Bands
Although UWB technology operates at the same or lower power levels currently allowed for numerous applications under the FCC’s Part 15 rules, a change of the rules is needed to accommodate this new form of wireless technology
Not
to s
cale
May, 2001TIME DOMAIN®
US Regulatory Status of UWB
Presently billions of digital devices that emit UWB-like signals (laptops, PDAs, etc.)
Operate in the US under unlicensed “Part 15” rules
Basic requirement of Part 15: Thou shalt not create harmful
interference
May, 2001TIME DOMAIN®
What is Harmful Interference?
The FCC must decide what constitutes harmful interference. This is a critical spectrum management issue.
US Statutory definition of harmful interference (FCC) “Interference which endangers the functioning of a
radionavigation service or other safety services or seriously degrades, obstructs or repeatedly interrupts a radio communications service operating in accordance with these [international] Radio Regulations.” 47 CFR 2.1
US NTIA definition NTIA ITS website adds that harmful interference “must cause
serious detrimental effects such as circuit outages and message losses as opposed to interference that is merely a nuisance or annoyance that can be overcome by appropriate measures.”
May, 2001TIME DOMAIN®
Rule Change: “Noise is Noise”Regardless of What Causes It
Radio-wave power (noise) causes interference Interference has nothing to do with whether the noise source is
an “intentional” or “unintentional” emitter Appropriate measure is power level, not “intent”
UWB power limits set by FCC should be: Equivalent to power limits for both “unintentional” and
“spurious” emissions (-71dBW/MHz, the Part 15 power level) Lower than out-of-band power limits allowed for licensed
services e.g., PCS and MSS are allowed to emit slightly more energy in
restricted bands than all Part 15 devices
UWB power limits are no different than levels emitted by existing Part 15 devices. Therefore, UWB should be treated like other Part 15 devices: Intentional vs. unintentional distinction is unnecessary
May, 2001TIME DOMAIN®
GPS Coexistence Testing
Johns Hopkins Applied Physics Laboratory Sponsored by Time Domain Analyzed data taken by Applied Research
Laboratory, University of Texas (ARL:UT) Comprehensive testing produced 20 GB of data
including conducted and radiated testing of multiple receiver types and UWB modes as well as other digital devices operating at Part 15 power
Developed 12 measures of GPS receiver performance related to number of satellites, position accuracy, and reacquisition time
May, 2001TIME DOMAIN®
An Example Graph fromJHUAPL Report
Asymptotic curve with noticeable effects starting at 3 meters
May, 2001TIME DOMAIN®
JHUAPL Analytic Results
TM-UWB emissions are white noise-like signals that can be modeled as average power
Multiple TM-UWB emissions add as average power TM-UWB emissions resemble emissions from devices
operating at Part 15 power levels– un-keyed walkie-talkie Developed theoretical model that accurately predicted
both ARL:UT and other experimental data DoD Joint Spectrum Center recently showed that NTIA
and UT/JHU data largely say the same thing. TDC performed similar analysis
May, 2001TIME DOMAIN®
Aggregate Issue
Why isn’t the night sky as bright as the day? Can’t be an aggregate issue on the large
scale if the average propagation path is less than free space
Except over very short ranges, free space paths don’t exist
At the power levels that the FCC may authorize, applications must be short range applications
May, 2001TIME DOMAIN®
Conclusions
The benefits of UWB are unique, and in many cases cannot be realized using other technologies
UWB can be introduced at Part 15 power levels without causing harmful interference
