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UWB - The Potential and the Cont

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					Marcus Spectrum Solutions   Consulting Services in Radio Technology and Spectrum Policy




            UWB - The Potential and the
                   Controversy
                              Michael J. Marcus,                                Sc.D., FIEEE
                                             Director
                              Marcus Spectrum Solutions, Paris, France
                                     mjmarcus@alum.mit.edu
                                   www.marcus-spectrum.com




                                                    ICU 2005 ETH Zurich                        1
                                                 IUWB Zurich Keynote 6/9/05
Likely UWB Market Target
              Plus
                Ground penetrating
                   radar

                Through-the-wall
                   radar

                Tracking systems
                                   2
    Other UWB Advantages
Doesn’t need licensed dedicated
 spectrum
Low power consumption
Small semiconductor size
Ranging/location as a byproduct of
 communications


                                      3
 Some UWB Technical History
         Sources

http://www.aetherwire.com/
 CDROM/General/papers.html


http://www.multispectral.com/
 history.html
                                 4
UWB Background: Technology
Early sparkgap radio systems were similar in
  some ways to UWB and occupied large
  bandwidths
Growth in demand for capacity necessitated
  spectrum sharing
 Any orthogonal multiplex system could share
  spectrum
  A basis set made of sinusoids was the only
   available one in early days of radio and remains
   viable for most uses today
  Sinusoids replaced sparks and “Class B” emissions
                                                     5
   banned by ITU
UWB Background: Technology
 Like the invention of the computer,
 origin of UWB somewhat convoluted
  TD analysis of microwave networks is one
   origin
  Work of Prof. Harmuth at Catholic
   University of America in 1970s on Walsh
   functions as an alternative basis set was
   another


                                               6
UWB Background: Technology
              Ross 1973 patent may
               be the first
              By 1989, Sperry Rand
               had more than 50 UWB
               patents but no civil
               applications
              1987 Time Domain
               Corp. founded
                Initial work all
                 government

                                      7
   UWB Background:
     Regulation




Where did this come from?   8
          UWB Background:
            Regulation
Why underlays?
  “White space” problem
    In the real world there are significant gaps in
     spectrum use at a given place at a given time
    Major spectrum policy issue is how to “recycle”
     this white space responsibly
  Growing demand for short range, high
   capacity links to supplement existing IT
   systems
                                                   9
         UWB Background:
           Regulation
What is “harmful interference”
ITU definition came from a different era
 where interference was more binary
Is “interference” that is small compared
 to naturally occurring problems
 “harmful”
  US Northpoint 12 GHz DBS/BSS precedent
    Outage increase <5% of rain-related outage is
     OK                                          10
            UWB Background:
              Regulation
1981-85 FCC Docket 81-413
  Intended to explore potential of spread spectrum
   in civil applications
  Resulted in ISM bands for unlicensed, e.g. Wi-Fi
  Stimulated development of CDMA cellular
  Initial proposals were broad enough to include
   UWB
     All proposals were broadly criticized by existing radio
      users
     No real advocates for “underlays”
     ISM band chosen as a safe place to explore CDMA

                                                                11
              UWB Background:
                Regulation
1989 rewrite of FCC Part 15 rules aimed to
 generalize concepts and decrease specific rules
 for specific devices
New 15.209 allowed unlicensed use on most
 frequencies subject to PC emission limit
  At insistence of NTIA, certain bands are exempted
   from any such emissions - 15.205
But, please note that real PCs do not actually
 emit all the time on all frequencies

                                                       12
Roots of FCC UWB Decision

                             Capital
                             Formation

        St. Valentine Day
               2002
         FCC Decision
                        Intense
                        lobbying




                                         13
  St. Valentine’s Day 2002
“The Perfect Storm” of Spectrum Policy
           Why did UWB get authorized
            when previous attempts got
            nowhere?
           Bush administration appoints 3
            political appointees with
            technical business
            backgrounds in key positions:
              Steve Price/DoD
              Mike Gallagher/NTIA
              Ed Thomas/FCC
                                         14
    St. Valentine’s Day 2002
 “The Perfect Storm” of Spectrum Policy
In previous years vested interests had
 blocked almost all consideration of underlays
Realities of new millennium allow issues to be
 addressed on their merits
Approval complicated by concerns over 2
 relatively recent developments
  GPS/”Assisted” (indoor) GPS
  CDMA cellular

                                              15
         UWB Background:
           Regulation
“.com Boom” in late 1990s stimulates
 interest in novel radio technologies
  “Serious money” could be made in IPOs of
   high tech firms
Time Domain Corp. raises funding
 estimated at $50-100M for development
 of UWB and the regulatory fight needed
 to get it approved
  Possibly 50% budgeted for regulatory fight
                                            16
  UWB Background:
Regulation - UK Version
            UK Ofcom has
             attempted to balance
             costs and benefits of
             UWB
              US focus was declaring
               costs to be de minimis
            But analysis is only as
             good as assumptions


                                  17
                ITU-R
Good News
 TG1/8 will complete its work in
  October 2005
 Expected to reach consensus on 3
  documents
Bad News
 Unlikely to reach consensus on key
  document
                                       18
   UWB EMC Analysis Issues
Key to UWB Policy Development
It is easy for both sides to be “blinded by
 ideology” in analyzing novel EMC issues
 posed by UWB
It is tempting to apply existing EMC standards
 out of the context for which they were
 intended
  and which may not have been well documented

                                                 19
     Basic UWB EMC Issues
Receivers only see UWB power within
 their receive bandwidth
If PRF is greater than receive
 bandwidth and pulses dithered UWB
 appears noise-like
If PRF is less than receive bandwidth
 UWB appears impulsive

                                         20
     Basic UWB EMC Issues
UWB emitter creates a local increase in
 noise which decreases with distance
 depending on appropriate propagation
 model
For some weak desired signals this can
 adversely impact SNR
“Burnthrough” -change in geometry can
 cure SNR problem

                                       21
Basic UWB EMC Issues: CDMA
In basic decade CDMA cellular has
 become common
CDMA systems are impacted differently
 by noise increases than FDMA or TDMA
In an ideal RF noise environment, UWB
 would decrease capacity of CDMA LM
 systems
Impact in realistic environments more
 complex
                                     22
“Aggregation”
       “Aggregation”
        continues to be the
        “Count Dracula” of
        spectrum
        management
       Aggregation actually
        is a real concern,
        but is exaggerated
        by some

                           23
             “Aggregation”
Aggregation is the possible accumulation of
 undesired signal power at a victim receiver
 resulting from many UWB transmitters.
Depends on various factors such as minimum
 distance to closest UWB source and nature of
 propagation
In most real applications there is a practical
 minimum distance or cutoff of uncooperative
 signal sources
  Modeling UWB location as a pair of i.i.d. random
   variates is unrealistic                            24
          “Aggregation”
           Closest Interferer Issue

Modeling UWB location as a pair of i.i.d.
 random variates is simple but in the real
 world there is a minimum distance for
 unrelated sources
  Each person has some space around them
   under there own control ~ 0.5 - 2m
  Each residence has a similar space 3 - 20m
  These bound location of closest interferer


                                             25
             “Aggregation”
Aggregation is a real threat in cases of free
 space paths such as in ground-air
 communications and satellite uplinks
  In these situations victim could see a large
   number of UWB devices with free space paths
However, most applications involve terrestrial
 paths and “victims” with more complex
 propagation characteristics


                                                  26
             “Aggregation”
With square power
 law power will                                              UWB User Density        Square Law

 aggregate with                                     0




                         Relative Received Power
                                                         0      10    20        30    40    50    60
                                                    -5


 number of users                                   -10

                                                   -15


But location of                                   -20




 closest user is a key
                                                   -25

                                                   -30



 factor                                            -35

                                                   -40

                                                   -45




                                                                                                  27
             “Aggregation”
For  >2 in
 propagation, typical                                        UWB User Density   4th Power Law

 of terrestrial paths,                              0




                         Relative Received Power
                                                         0        10      20    30     40       50   60


 integrals summing
                                                   -10

                                                   -20


 to infinity converge                              -30



 so aggregation                                    -40

                                                   -50

 converges                                         -60



Nearest interferer is
                                                   -70

                                                   -80

 still key                                         -90




                                                                                                28
         “Aggregation”
For  =2 (square
 law) integral of                     Upper limit of integral (distance)

 power received at a   -20
                             0   20     40    60    80    100   120   140   160



 victim receiver
                                               Square Law
                       -25




 increases as upper    -30




 limit of integral     -35




 increases             -40

                                                    4th Power

For  =4 integral
                       -45




 converges
                       -50




                                                                            29
   Microwave Landing System
            (MLS)
                                                                               11/01


   When the aircraft is at the
   maximum range (43 nautical mi) of
   the MLS (e.g. minimum MLS signal)
   the aircraft is at too great an
   altitude for any possible UWB       • NTIA analysis assumed minimum MLS
   device to affect performance          signal to derive the 160 m protection
                                         criteria range
                                       • BUT, aircraft must be over the runway to
                                         be that close.
                                       • There is at least 34 dB more signal from
                                         the MLS when the aircraft is landing

10,000 ft
(3050 m)                                           160m

                                                                UWB
                             80m


                                            1 mi                             30
                        43 nmi                               MLS
                     Radar Issues
To understand these issues you have to be realistic about antenna siting


          Nearby
          Office
          Building


              Radar




     FAA/NTIA Viewpoint                         FCC Viewpoint
                                                                31
               Radiation Hazards                                    11/01


    Aircraft – 300 V/m peak
        FAA, 14 CFR Parts 21 & 25, Federal Register May 16, 1988
    Critical Medical Electronic Devices
          IEC – 3 V/m
          AF report SAM-TR-76-4 (e.g. Pacemakers etc.): – 200 V/m peak
          ASR-9     – 1.4 km            TDWR     – 4.3 km
          ARSR-4 – 1.1 km               NEXRAD – 4.5 km
    Personal Exposure Limit (PEL) – 1 mW/cm2
        DOD instruction 6055 and ANSI C95.1-1982
    Fuels – 3.1 kV/m peak
        DNA 4284-F-SAS-1 Dec 1979
    Explosives – 12.4 kV/m
        DNA 4284-F-SAS-1 Dec 1979


It is not reasonable to base regulations on geometries that put
                                                             32
the UWB user in field strengths that are not safe not safe
UWB Schism




             33
                                          Mike Gallagher (NTIA)
                                                    on
                                          UWB Emission Masks
http://www.ntia.doc.gov/ntiahome/speeches/2005/MGallagher_UWB_05212005.ppt
       “A technically based approach (measurements and analysis) was used to
          develop the UWB emission limits necessary to protect the radio frequency
          spectrum used by GPS as well as other current and future radionavigation
          satellite systems.

       To date, all credible studies
          have shown the U.S.
          developed UWB emission
          limits adequately protect GPS
          receivers (based on 2 meter
          distance separation and
          protection of assisted
          GPS receiver technology).”

                                                                               34
         UWB Controversy
While Time Domain Corp. deserves
 credit for its pyrrhic victory in getting
 UWB regulations in US, its sometimes
 outrageous claims also incited
 opponents
Most notable: UWB can be used for a
 cellular service without buying a license

                                         35
      Please Be Careful Making
               Claims
 Wire free Harmony … The combination of broader spectrum, lower
  power and pulsed data means that Ultra-Wideband causes significantly
  less interference than conventional narrowband radio solutions while
  safely coexisting with other wireless technologies on the market.
  http://www.uwbforum.org

 No harmful interference…Thanks to its low spectral density,
  unlicensed UWB radio emissions do not add up to cause
  harmful interference to other radio systems operating in
  dedicated bands. In fact, normal propagation attenuation
  causes the signals to dissipate faster than they can add up
  http://www.commsdesign.com/design_corner/OEG20020301S0021


 Both of these claims are true to a certain
  degree -- but also leave out some key “fine
  print”                                                            36
A Historic Slide That Still
      Holds Truth




                              37
                 UWB is Coming!
 “A 37-inch high definition television from Chinese company
  Haier was shown using an integrated UWB link to a digital
  media server. The products will ship in the Chinese market in
  the last quarter of 2005 and in the US in 2006.”
   ZDNet UK June 22, 2005


 “Research firm West Technology Research Solutions
  says that when Freescale Semiconductor ships its DS-
  UWB chips in the third quarter of this year, it will spur
  "significant economic growth" in ultrawideband circles.
  They expect DS-UWB components to have a market
  worth $482 million by 2010, with annual shipments in
  consumer electronics alone hitting around 38 million
  units by 2009.”

                                                                  38
    UWB - A Pragmatic View
UWB is cleared for the US market and is
 coming
If it meets real consumer needs and
 predictions of no EMC problems are
 confirmed in actual use -- spread to
 other countries is inevitable
Let’s get ready for it!

                                       39
Marcus Spectrum Solutions     Consulting Services in Radio Technology and Spectrum Policy




          UWB - The Potential and the
                 Controversy

                                  Michael J. Marcus,                      Sc.D., FIEEE
                                           Director
                            Marcus Spectrum Solutions, Paris, France
                                   mjmarcus@alum.mit.edu
                                 www.marcus-spectrum.com


                                                    ICU 2005 ETH Zurich                     40
                                                  IUWB Zurich Keynote 6/9/05

				
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