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 Federal  Communications  Commission  FCC  02-  48 
 Before  the  Federal  Communications  Commission 
 Washington,  D.  C.  20554 

 In  the  matter  of 
 Revision  of  Part  15  of  the  Commissions  Rules  Regarding  Ultra-  Wideband  Transmission 
 Systems 

 )  ) 
 )  ) 
 )  )  ET  Docket  98-  153 

 FIRST  REPORT  AND  ORDER 
 Adopted:  February  14,  2002  Released:  April  22,  2002 
 By  the  Commission:  Commissioners  Copps  and  Martin  issuing  separate  statements. 
 Page  I.  INTRODUCTION  ...........................................................................................................................  2 
 II.  EXECUTIVE  SUMMARY  .............................................................................................................  3  III.  BACKGROUND  .............................................................................................................................  4 
 IV.  DISCUSSION..................................................................................................................................  7 
 A.  Authorization  and  Regulatory  Treatment  of  UWB.............................................................  7 
 B.  UWB  Definition................................................................................................................  12 
 C.  Frequency  Bands  and  Operational  Requirements  for  UWB  Devices  ...............................  16  1.  Imaging  Systems..................................................................................................  18 

 2.  Other  UWB  Devices  ............................................................................................  23 
 D.  Analyses  of  Interference  Studies  ......................................................................................  27  1.  NTIA,  DOT  and  TDC  Analyses  of  Potential  Interference  to  GPS  .....................  28 

 2.  NTIA  Analyses  of  Interference  to  Various  U.  S.  Government  Systems:..............  44  3.  U.  S.  Department  of  Defense  Analysis  of  Interference  to  the  SGLS....................  53 
 4.  ARRL  Analysis  of  Noise  Floor  Increase  in  Amateur  Radio  Bands....................  53  5.  Analyses  of  Potential  Interference  to  PCS...........................................................  54 
 6.  Cisco  Analysis  of  Potential  Interference  to  MMDS  ............................................  57  7.  XM  Analysis  of  Potential  Interference  to  DARS  ................................................  58 
 8.  Summary  of  Tests  and  Analyses..........................................................................  59 
 E.  Emission  Limits  ................................................................................................................  60  1.  General.................................................................................................................  60 

 2.  Average  and  Quasi-  peak  Emission  Levels  ..........................................................  62  3.  Imaging  Systems  Including  GPRs  .......................................................................  65 
 4.  Other  Applications...............................................................................................  66  5.  Emission  Levels  above  1990  MHz  ......................................................................  70 
 6.  Dithering  and  Other  Noise-  Like  Emission  Requirements  ...................................  71  7.  Emissions  from  Incorporated  Digital  Devices.....................................................  72 
 8.  Peak  Emission  Limits  ..........................................................................................  72  9.  AC  Power  Line  Conducted  Limits.......................................................................  77 
 10.  Summary  of  Emission  Limits  Being  Adopted  in  this  Report  and  Order  .............  77 
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 F.  Cumulative  Impact............................................................................................................  79 
 G.  Measurement  Procedures..................................................................................................  81  1.  Quasi-  peak  and  Average  Measurements..............................................................  82 

 2.  Peak  Measurements  .............................................................................................  84  3.  Frequency  Range  of  Measurement  ......................................................................  86 

 H.  Prohibition  Against  Class  B,  Damped  Wave  Emissions...................................................  87 
 I.  Other  Matters  ....................................................................................................................  88  1.  Operation  of  Wide  Bandwidth  Systems  under  the  Existing  Rules  ......................  88 

 2.  Transition  Provisions  ...........................................................................................  89  3.  Existing  Waivers..................................................................................................  90 
 4.  Miscellaneous  Issues............................................................................................  90  5.  Other  Matters  .......................................................................................................  91 
 V.  PROCEDURAL  MATTERS  .........................................................................................................  92  VI.  ORDERING  CLAUSES................................................................................................................  94 

 APPENDIX  A:  Commenting  Parties  APPENDIX  B:  Comments  in  Response  to  NTIAs  Study  of  Potential  Interference  to  Non-  GPS  Systems 
 APPENDIX  C:  Comments  in  Response  to  Studies  of  Potential  Interference  to  GPS  Systems  and  to  Personal  Communications  Services 
 APPENDIX  D:  Changes  to  the  Regulations  APPENDIX  E:  Peak  in  a  Specific  Bandwidth  vs.  Average  in  a  1  MHz  Bandwidth  vs.  PRF 
 APPENDIX  F:  Measurement  Procedures 
 I.  INTRODUCTION 
 1.  By  this  action,  we  are  amending  Part  15  of  our  rules  to  permit  the  marketing  and  operation  of  certain  types  of  new  products  incorporating  ultra-  wideband  ("  UWB")  technology.  UWB 

 devices  operate  by  employing  very  narrow  or  short  duration  pulses  that  result  in  very  large  or  wideband  transmission  bandwidths.  UWB  technology  holds  great  promise  for  a  vast  array  of  new  applications  that 
 we  believe  will  provide  significant  benefits  for  public  safety,  businesses  and  consumers.  With  appropriate  technical  standards,  UWB  devices  can  operate  using  spectrum  occupied  by  existing  radio 
 services  without  causing  interference,  thereby  permitting  scarce  spectrum  resources  to  be  used  more  efficiently.  This  First  Report  and  Order  (  Order)  includes  standards  designed  to  ensure  that  existing  and 
 planned  radio  services,  particularly  safety  services,  are  adequately  protected.  We  are  proceeding  cautiously  in  authorizing  UWB  technology,  based  in  large  measure  on  standards  that  the  National 
 Telecommunications  and  Information  Administration  (  NTIA)  found  to  be  are  necessary  to  protect  against  interference  to  vital  federal  government  operations.  These  UWB  standards  will  apply  to  UWB 
 devices  operating  in  shared  or  in  non-  government  frequency  bands,  including  UWB  devices  operated  by  U.  S.  Government  agencies  in  such  bands.  We  are  concerned,  however,  that  the  standards  we  are  adopting 
 may  be  overprotective  and  could  unnecessarily  constrain  the  development  of  UWB  technology.  Accordingly,  within  the  next  six  to  twelve  months  we  intend  to  review  the  standards  for  UWB  devices 
 and  issue  a  further  rule  making  to  explore  more  flexible  technical  standards  and  to  address  the  operation  of  additional  types  of  UWB  operations  and  technology. 

 2.  This  has  been  an  unusually  controversial  proceeding  involving  a  variety  of  UWB  advocates  and  opponents.  These  parties  have  been  unable  to  agree  on  the  emission  levels  necessary  to 
 protect  Government-  operated,  safety-  of-  life  and  commercial  radio  systems  from  harmful  interference.  It  is  our  belief  that  the  standards  contained  in  this  Order  are  extremely  conservative.  These  standards  may 
 change  in  the  future  as  we  continue  to  collect  data  regarding  UWB  operations.  The  analyses  and  technical  standards  contained  in  this  Order  are  unique  to  this  proceeding  and  will  not  be  considered  as  a 
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 basis  for  determining  or  revising  standards  for  other  radio  frequency  devices,  including  other  Part  15  devices. 
 3.  The  following  text  first  provides  an  executive  summary  of  the  major  actions  taken  in  this  item.  Next,  a  background  section  describing  Part  15  of  the  Commission's  rules  and  the  history  of  this 
 proceeding  is  provided.  A  comprehensive  discussion  section  consisting  of  several  parts  is  also  included.  The  first  section  of  the  discussion  focuses  on  regulatory  treatment  and  the  Commission's  definition  of 
 ultra  wideband  technology.  The  next  part  of  the  discussion  provides  analyses  of  studies  submitted  by  several  parties  assessing  the  interference  potential  of  ultra  wideband  devices  to  existing  services.  This 
 section  is  followed  by  a  discussion  of  the  emission  limits  established  for  ultra  wideband  deployment.  Also  included  in  the  discussion  section  are  assessments  of  the  cumulative  impact  of  ultra  wideband 
 devices  and  procedures  for  measuring  the  emissions  from  ultra  wideband  devices.  Finally,  the  discussion  concludes  with  a  section  on  other  matters  that  impact  the  authorization  of  UWB  technology. 

 II.  EXECUTIVE  SUMMARY 
 4.  Upon  consideration  of  the  record,  we  continue  to  believe  that  UWB  technology  offers  significant  benefits  for  Government,  public  safety,  businesses  and  consumers.  However,  we  recognize 

 that  these  substantial  benefits  could  be  outweighed  if  UWB  devices  were  to  cause  interference  to  licensed  services  and  other  important  radio  operations.  Our  analysis  of  the  record  and  the  various  technical  studies 
 submitted  indicate  that  UWB  devices  can  be  permitted  to  operate  on  an  unlicensed  basis  without  causing  harmful  interference  provided  appropriate  technical  standards  and  operational  restrictions  are  applied  to 
 their  use. 
 5.  To  ensure  that  UWB  devices  do  not  cause  harmful  interference,  this  Order  establishes  different  technical  standards  and  operating  restrictions  for  three  types  of  UWB  devices  based  on  their 

 potential  to  cause  interference.  These  three  types  of  UWB  devices  are:  1)  imaging  systems  including  Ground  Penetrating  Radars  (GPRs)  and  wall,  through-  wall,  surveillance,  and  medical  imaging  devices,  2) 
 vehicular  radar  systems,  and  3)  communications  and  measurement  systems.  Generally,  we  are  adopting  unwanted  emission  limits  for  UWB  devices  that  are  significantly  more  stringent  than  those  imposed  on 
 other  Part  15  devices;  limiting  outdoor  use  of  UWB  devices  to  imaging  systems,  vehicular  radar  systems  and  hand  held  devices;  and,  limiting  the  frequency  band  within  which  certain  UWB  products  will  be 
 permitted  to  operate.  The  frequency  band  of  operation  is  based  on  the  10  dB  bandwidth  of  the  UWB  emission.  This  combination  of  technical  standards  and  operational  restrictions  will  ensure  that  UWB 
 devices  coexist  with  the  authorized  radio  services  without  the  risk  of  harmful  interference  while  we  gain  experience  with  this  new  technology.  In  the  meantime,  we  plan  to  expedite  enforcement  action  for  any 
 UWB  products  found  to  be  in  violation  of  the  rules  we  are  adopting  and  will  act  promptly  to  eliminate  any  reported  harmful  interference  from  UWB  devices.  Specifically,  the  Order  takes  the  following 
 actions: 
   Imaging  Systems:  Provides  for  the  operation  of  GPRs  and  other  imaging  devices  under  Part  15  of  the  Commissions  rules  subject  to  certain  frequency  and  power  limitations.  All  imaging 
 systems  are  subject  to  coordination  with  NTIA  through  the  FCC.  NTIA  has  indicated  that  coordination  will  be  as  expeditious  as  possible,  requiring  no  longer  than  15  business  days, 
 and  may  be  expedited  in  emergency  situations.  The  operators  of  imaging  devices  must  be  eligible  for  licensing  under  Part  90  of  our  rules,  except  that  medical  imaging  devices  may  be 
 operated  by  a  licensed  health  care  practitioner.  Imaging  systems  include: 
   Ground  Penetrating  Radar  Systems:  GPRs  must  be  operated  below  960  MHz  or  in  the  frequency  band  3.1-  10.  6  GHz.  GPRs  operate  only  when  in  contact  with,  or  within  close 
 proximity  of,  the  ground  for  the  purpose  of  detecting  or  obtaining  the  images  of  buried  objects.  The  energy  from  the  GPR  is  intentionally  directed  down  into  the  ground  for  this 
 purpose.  Operation  is  restricted  to  law  enforcement,  fire  and  rescue  organizations,  to 
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 scientific  research  institutions,  to  commercial  mining  companies,  and  to  construction  companies. 
   Wall  Imaging  Systems:  Wall  imaging  systems  must  be  operated  below  960  MHz  or  in  the  frequency  band  3.1-  10.  6  GHz.  Wall-  imaging  systems  are  designed  to  detect  the 
 location  of  objects  contained  within  a  wall,  such  as  a  concrete  structure,  the  side  of  a  bridge,  or  the  wall  of  a  mine.  Operation  is  restricted  to  law  enforcement,  fire  and  rescue 
 organizations,  to  scientific  research  institutions,  to  commercial  mining  companies,  and  to  construction  companies. 

   Through-  wall  Imaging  Systems:  These  systems  must  be  operated  below  960  MHz  or  in  the  frequency  band  1.  99-  10.  6  GHz.  Through-  wall  imaging  systems  detect  the  location  or 
 movement  of  persons  or  objects  that  are  located  on  the  other  side  of  a  structure  such  as  a  wall.  Operation  is  limited  to  law  enforcement,  fire  and  rescue  organizations. 

   Surveillance  Systems:  Although  technically  these  devices  are  not  imaging  systems,  for  regulatory  purposes  they  will  be  treated  in  the  same  way  as  through-  wall  imaging 
 systems  used  by  police,  fire  and  rescue  organizations  and  will  be  permitted  to  operate  in  the  frequency  band  1.99-  10.6  GHz.  Surveillance  systems  operate  as  security  fences  by 
 establishing  a  stationary  RF  perimeter  field  and  detecting  the  intrusion  of  persons  or  objects  in  that  field.  Operation  is  limited  to  law  enforcement,  fire  and  rescue 
 organizations,  to  public  utilities  and  to  industrial  entities. 
   Medical  Systems:  These  devices  must  be  operated  in  the  frequency  band  3.1-  10.6  GHz.  A  medical  imaging  system  may  be  used  for  a  variety  of  health  applications  to  see 
 inside  the  body  of  a  person  or  animal.  Operation  must  be  at  the  direction  of,  or  under  the  supervision  of,  a  licensed  health  care  practitioner. 

   Vehicular  Radar  Systems:  Provides  for  the  operation  of  vehicular  radar  in  the  22-  29  GHz  band  using  directional  antennas  on  terrestrial  transportation  vehicles  provided  the  center 
 frequency  of  the  emission  and  the  frequency  at  which  the  highest  radiated  emission  occurs  are  greater  than  24.075  GHz.  These  devices  are  able  to  detect  the  location  and  movement  of 
 objects  near  a  vehicle,  enabling  features  such  as  near  collision  avoidance,  improved  airbag  activation,  and  suspension  systems  that  better  respond  to  road  conditions.  Attenuation  of  the 
 emissions  below  24  GHz  is  required  above  the  horizontal  plane  in  order  to  protect  space  borne  passive  sensors  operating  in  the  23.6-  24.0  GHz  band. 

   Communications  and  Measurement  Systems:  Provides  for  use  of  a  wide  variety  of  other  UWB  devices,  such  as  high-  speed  home  and  business  networking  devices  as  well  as  storage 
 tank  measurement  devices  under  Part  15  of  the  Commissions  rules  subject  to  certain  frequency  and  power  limitations.  The  devices  must  operate  in  the  frequency  band  3.1-  10.6 
 GHz.  The  equipment  must  be  designed  to  ensure  that  operation  can  only  occur  indoors  or  it  must  consist  of  hand  held  devices  that  may  be  employed  for  such  activities  as  peer-  to-  peer 
 operation. 
 III.  BACKGROUND 
 6.  Part  15  of  our  rules  permits  the  operation  of  authorized  low  power  radio  frequency  (RF)  devices  without  a  license  from  the  Commission  or  the  need  for  frequency  coordination.  1  The  technical 

 1  Devices  are  permitted  to  operate  after  they  have  been  verified  to  comply  with  existing  operational 
 restrictions.  See  47  C.  F.  R.  Chapter  2,  Subpart  J.  &  47  C.  F.  R.    15.1  et  seq. 
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 standards  contained  in  Part  15  are  designed  to  ensure  that  there  is  a  low  probability  that  these  unlicensed  devices  will  cause  harmful  interference  to  other  users  of  the  radio  spectrum.  2  Part  15  intentional 
 radiators,  i.  e.,  radio  transmitters,  are  permitted  to  operate  under  a  set  of  general  emission  limits  3  or  under  provisions  that  allow  higher  emission  levels  in  certain  frequency  bands.  4  Part  15  intentional  radiators 
 generally  are  not  permitted  to  operate  in  certain  sensitive  5  or  safety-  related  frequency  bands  that  are  designated  as  restricted  bands,  6  or  in  the  frequency  bands  allocated  for  television  (  TV)  broadcasting. 
 Only  out-  of-  band  or  spurious  emissions  from  Part  15  transmitters  are  permitted  in  these  restricted  bands. 
 7.  UWB  radio  systems  typically  employ  pulse  modulation  where  extremely  narrow  (short)  bursts  of  RF  energy  are  modulated  and  emitted  to  convey  information.  Because  of  the  very  short  duration 

 of  these  pulses,  the  emission  bandwidths  from  these  systems  are  large  and  often  exceed  one  gigahertz.  7  In  some  cases,  impulse  transmitters  are  employed  where  the  pulses  do  not  modulate  a  carrier.  Instead,  the 
 radio  frequency  emissions  generated  by  the  pulses  are  applied  to  an  antenna,  and  the  resonant  frequency  of  the  antenna  determines  the  center  frequency  of  the  radiated  emission.  The  frequency  response 
 characteristics  of  the  antenna  provide  band-  pass  filtering,  further  affecting  the  shape  of  the  radiated  signal.  UWB  devices  can  be  used  for  precise  measurement  of  distances  or  locations  and  for  obtaining  the 
 images  of  objects  buried  under  ground  or  behind  surfaces.  UWB  devices  can  also  be  used  for  wireless  communications,  particularly  for  short-  range  high-  speed  data  transmissions  suitable  for  broadband  access 
 to  networks. 
 8.  The  current  Part  15  rules  pose  two  primary  obstacles  to  the  implementation  of  UWB  technology.  First,  the  wide  bandwidth  that  is  intrinsic  to  the  operation  of  UWB  devices  can  result  in 

 transmission  of  the  intentional  emissions  into  restricted  frequency  bands  or  into  the  TV  broadcast  frequency  bands,  which  is  prohibited  under  the  Part  15  rules.  Second,  the  current  emission  measurement 
 procedures  specified  in  our  Part  15  rules  were  developed  for  relatively  narrowband  systems  and  may  be  inappropriate  for,  and  pose  unnecessary  restrictions  to,  UWB  technology,  particularly  impulse  systems. 
 For  example,  the  Part  15  measurement  procedures  require  the  application  of  a  pulse  desensitization  correction  factor.  8  The  application  of  this  correction  factor  is  not  appropriate  for  very  wideband  systems 
 and  may  can  cause  UWB  systems  to  exceed  the  peak  emission  limits  currently  specified  under  the  Part  15 

 2  In  addition  to  the  limiting  technical  constraints,  one  of  the  primary  operating  conditions  under  Part  15  are 
 that  the  operator  must  accept  whatever  interference  is  received  and  must  correct  whatever  interference  is  caused.  Should  harmful  interference  occur,  the  operator  is  required  to  immediately  correct  the  interference  problem,  even  if 

 correction  of  the  problem  requires  ceasing  operation  of  the  Part  15  system  causing  the  interference.  See  47  C.  F.  R.    15.5. 
 3  See  47  C.  F.  R.    15.209. 
 4  See  47  C.  F.  R.    15.215-  15.  407.  In  some  cases,  operation  at  the  higher  emission  levels  within  these 
 designated  frequency  bands  is  limited  to  specific  applications.  5 
 The  sensitive  bands  referenced  here  are  bands  employed  by  radio  services  that  must  function,  as  a  nature  of  their  operation,  using  extremely  low  received  signal  levels.  These  systems  may  be  passive,  such  as  radio  astronomy, 

 or  active,  such  as  satellite  down  links  and  wildlife  tracking  systems.  6 
 See  47  C.  F.  R.    15.205.  7 
 Typical  pulse  widths  used  by  UWB  devices  currently  are  on  the  order  of  0.1-  2  nanoseconds,  or  less,  in  width.  The  emission  spectrum  appears  as  a  fundamental  lobe  with  adjacent  side  lobes  that  can  decrease  slowly  in 

 amplitude.  The  rise  time  of  the  leading  edge  of  the  pulse  and  the  passband  of  the  radiating  antenna  are  major  factors  in  determining  the  bandwidth  of  the  UWB  emission. 
 8  HP  Application  Note  150-  2  specifies  the  use  of  a  pulse  desensitization  correction  factor. 
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 rules.  9 
 9.  The  Federal  Government  operates  safety-  of-  life  and  other  critical  systems  in  several  of  the  restricted  frequency  bands  and  has  raised  concerns  about  the  potential  for  UWB  devices  to  interfere 

 with  these  operations.  The  National  Telecommunications  and  Information  Administration  (NTIA)  at  the  U.  S.  Department  of  Commerce  is  responsible  for  managing  the  Federal  Government's  use  of  the  radio 
 frequency  spectrum.  In  this  capacity,  NTIA  conducted  measurements  and  analysis  of  potential  interference  to  a  range  of  Federal  systems  including,  for  example,  the  Global  Positioning  System,  Search 
 and  Rescue  Satellite  System,  Air  Traffic  Control  System,  and  Meteorological  Radar  System.  NTIA  and  the  FCC  have  worked  closely  throughout  this  proceeding  to  ensure  that  the  public  interest  is  best  served 
 by  the  implementation  of  UWB  technology.  Specifically,  the  two  agencies  have  worked  together  to  develop  a  regulatory  paradigm  that  permits  the  deployment  of  promising  new  UWB  technology  while 
 adequately  safeguarding  both  Government  and  non-  government  operations. 
 10.  On  May  10,  2000,  the  Commission  adopted  a  Notice  of  Proposed  Rule  Making  (  Notice)  that  proposed  rules  to  allow  the  operation  of  UWB  transmission  systems  under  the  Part  15  regulations.  10 

 In  the  Notice,  the  Commission  requested  comments  on  various  aspects  of  UWB  operation,  including  applications,  general  characteristics,  operation  on  an  unlicensed  basis,  how  UWB  should  be  defined,  the 
 frequency  ranges  of  operation,  appropriate  emission  levels,  cumulative  impact  concerns,  and  measurement  procedures.  In  addition,  the  Commission  requested  comments  concerning  the  existing 
 prohibition  against  Class  B,  damped  wave  emissions,  the  operation  of  wide  bandwidth  transmitters  under  the  existing  Part  15  rules,  and  the  transition  provisions  that  should  be  applied.  In  response  to  the  Notice, 
 the  Commission  received  159  comments  and  80  reply  comments,  as  shown  in  Appendix  A.  11 
 11.  Subsequent  to  the  Notice,  the  Commission,  on  January  24,  2001,  requested  comments  on  two  studies  presented  NTIA  regarding  the  potential  for  UWB  transmission  systems  to  cause  harmful 

 interference  to  U.  S.  Government  radio  operations  between  400  MHz  and  6000  MHz.  12  In  response  to  these  studies,  the  Commission  received  16  comments  and  7  reply  comments,  as  shown  in  Appendix  C. 
 Subsequent  to  the  NTIA  filing,  the  Commission,  on  March  26,  2001,  requested  comments  on  additional  studies  addressing  potential  interference  from  UWB  operation  to  the  Global  Positioning  System  (GPS) 
 and  to  the  Personal  Communications  Services  (PCS)  telephones.  13  Time  Domain,  14  NTIA,  15  and  the 

 9  See  47  C.  F.  R.    15.  35(  b)  and  15.209.  UWB  systems  that  operate  with  a  low  duty  cycle  would  have  peak  levels  that 
 are  quite  high  compared  to  the  average  emission  levels.  10 
 See  Notice  of  Proposed  Rule  Making  in  ET  Docket  No.  98-  153,  65  Fed.  Reg.  37332,  June  14,  2000,  http://  www.  fcc.  gov/  Bureaus/  Engineering_  Technology/  Documents/  Notices/  2000/  fcc00163.  doc.  See,  also,  Notice  of 

 Inquiry  in  ET  Docket  No.  98-  153,  63  Fed.  Reg.  50184,  September  21,  1998,  http://  www.  fcc.  gov/  Bureaus/  Engineering_  Technology/  Documents/  fedreg/  63/  50184.  pdf. 
 11  A  large  number  of  late  filed  comments  and  ex  parte  comments  continued  to  be  filed  in  this  proceeding  long 
 after  the  end  of  the  comment  period.  While  these  comments  were  examined  and  evaluated,  the  commenting  parties  are  not  shown  in  Appendix  A.  A  list  of  all  parties  filing  comments  in  this  proceeding  can  be  found  by  referencing 

 the  Commissions  Electronic  Comment  Filing  System  located  at  www.  fcc.  gov/  e-  file/  ecfs.  html.  12 
 See  NTIA  Special  Publication  01-  43,  Assessment  of  Compatibility  between  Ultrawideband  Devices  and  Selected  Federal  Systems,  January  2001,  and  NTIA  Report  01-  383,  The  Temporal  and  Spectral  Characteristics  of 

 Ultrawideband  Signals,  January  2001.  See,  also,  Public  Notice  of  January  24,  2001,  DA  01-  171.  13 
 See  Public  Notice  of  March  26,  2001,  DA  01-  753.  14 
 See  Time  Domains  submission  of  March  9,  2001,  Final  Report  UWB-  GPS  Compatibility  Analysis  Project,  8  March  2001,  prepared  by  Strategic  Systems  Department,  The  Johns  Hopkins  University/  Applied  Physics 

 Laboratory.  The  study  consists  of  testing  performed  by  the  University  of  Texas  along  with  an  analysis  by  the  Applied  Physics  Laboratory  of  Johns  Hopkins  University. 
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 Department  of  Transportation  16  submitted  GPS  interference  studies.  Qualcomm  submitted  the  PCS  study.  17  In  response  to  these  studies,  the  Commission  received  22  comments  and  16  reply  comments,  as 
 shown  in  Appendix  D.  18 
 IV.  DISCUSSION 
 A.  Authorization  and  Regulatory  Treatment  of  UWB 
 12.  In  the  Notice,  we  stated  that  UWB  technology  holds  significant  promise  for  a  vast  array  of  new  applications  and  devices,  which  may  offer  significant  benefits  for  public  safety,  businesses, 

 consumers,  and  could  enhance  competition  and  the  economy.  In  addition,  we  indicated  that  UWB  technology  might  enable  increased  use  of  scarce  spectrum  resources  by  sharing  frequencies  with  other 
 services  without  causing  interference.  We  noted  that  most  of  the  near-  term  applications  for  UWB  technology  involve  relatively  low  powers  and  short  operating  ranges.  Further,  most  UWB  devices  are 
 intended  to  be  mass  marketed  to  businesses  and  consumers  making  it  impractical  to  individually  license  each  device.  We  observed  that  these  characteristics  are  largely  consistent  with  devices  that  operate  on  an 
 unlicensed  basis  under  Part  15  of  the  rules.  Accordingly,  we  tentatively  concluded  that  regulating  UWB  devices  under  Part  15  of  the  Commissions  rules  would  be  appropriate.  19 

 13.  A  large  number  of  parties  filed  comments  in  response  to  the  Notice  supporting  the  authorization  of  UWB  technology  and  suggesting  applications  for  its  use.  While  many  of  these 
 endorsements  did  not  provide  technical  comments  on  the  operating  parameters  that  should  be  applied  to  UWB  devices,  they  do  provide  significant  insight  into  the  public  interest  and  demand  for  the  wide  array 
 of  products  that  could  be  developed  using  UWB  techniques.  Several  UWB  applications  including  ground  penetrating  radar  (GPR)  systems,  wall-  imaging  systems,  automotive  collision  avoidance  systems,  radar 
 level  gauges  used  in  storage  tanks,  and  communications  systems  received  significant  support.  Intel,  for  example,  believed  that  the  greatest  potential  use  is  short-  range  communications  in  the  home  or  business, 
 allowing  equipment  mobility  and  high  data  rates  to  facilitate  information  sharing.  20  Fantasma  noted  similar  applications  for  supplying  simultaneous  video,  audio,  and  Internet  use  throughout  homes,  schools, 

 (...  continued  from  previous  page)  15  See  NTIA  Special  Publication  01-  45,  Assessment  of  Compatibility  between  Ultrawideband  (UWB)  Systems 
 and  Global  Positioning  System  (GPS)  Receivers,  February  2001,  and  NTIA  Report  01-  384,  Measurements  to  Determine  Potential  Interference  to  GPS  Receivers  from  Ultrawideband  Transmission  Systems,  February  2001, 
 submitted  to  the  Commission  on  March  9,  2001.  16 
 See  the  study  submitted  March  21,  2001,  by  NTIA  on  behalf  of  the  Department  of  Transportation  regarding  tests  performed  by  Stanford  University. 

 17  See  the  March  5,  2001,  submission  of  Qualcomm. 
 18  As  with  the  Notice,  a  number  of  late  filed  comments  and  ex  parte  comments  were  filed  in  this  proceeding 
 regarding  the  potential  for  UWB  transmission  systems  to  cause  interference  to  GPS  receivers.  While  these  comments  were  examined  and  evaluated,  the  commenting  parties  are  not  shown  in  Appendix  D.  A  list  of  all  parties 

 filing  comments  in  this  proceeding  can  be  found  by  referencing  the  Commissions  Electronic  Comment  Filing  System  located  at  www.  fcc.  gov/  e-  file/  ecfs.  html. 
 19  While  the  Commission  recognized  that  UWB  technology  may  be  developed  for  higher  power  applications 
 such  as  wide-  area  mobile  radio  services,  it  found  that  such  applications  raised  many  new  and  novel  questions,  such  as  consistency  with  the  international  and  domestic  table  of  frequency  allocations,  and  how  such  services  might  be 

 licensed  to  share  spectrum  across  broad  frequency  ranges  used  by  multiple  existing  services  and  licensees.  As  there  was  insufficient  information  in  the  record  to  address  such  issues,  no  proposals  were  made  to  allow  high  power  UWB 
 devices  to  operate  under  Part  15  or  on  a  licensed  basis.  20 
 Intel  reply  comments  at  pg.  3. 
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 libraries,  medical  and  elder-  care  facilities,  and  businesses.  21  AT&  T  expressed  interest  in  providing  high  throughput,  short-  range  voice,  data  and  video  services  on  premises  and  campus  environments.  22  National 
 Safe  Skies  Alliance  believed  UWB  could  be  used  to  detect  airport  runway  incursions  and  provide  data  distribution  within  airport  terminals,  personnel  location,  and  other  features.  23  Siemens  Automotive  ZF 
 suggests  using  UWB  technology  for  forward  looking  and  lane  change  collision  avoidance  systems,  backup  warning  systems,  and  airbag  proximity  measurements.  24  TDC  noted  the  potential  for  using  UWB 
 devices  in  dozens  of  applications.  25 
 14.  Most  parties  supporting  UWB  also  support  authorization  of  UWB  technology  under  Part  15  unlicensed  operations.  Delphi,  Endress  Hauser,  Lucent  and  Bosch  note  that  they  intend  to  mass-market 

 UWB  devices  to  businesses  and  consumers.  They  argue  that  licensing  UWB  devices  would  be  impractical  and  unwieldy  and  would  increase  costs  to  consumers.  26  Valeo  Electronics  supports 
 unlicensed  operations  for  UWB  but  also  suggests  that  higher-  powered  UWB  use  should  be  permitted  with  individual  licensing  or  under  product-  specific  waivers.  27  Similarly,  Zircon,  while  supporting  unlicensed 
 operation  for  UWB  devices  complying  with  the  47  C.  F.  R.    15.209  emission  limits,  indicated  that  UWB  devices  that  comply  with  the  limits  for  Class  A  digital  devices  should  be  minimally  encumbered  by  any 
 licensing  requirements.  28 
 15.  In  general,  the  commenting  parties  associated  with  authorized  radio  services  are  opposed  to  authorization  of  UWB  technology  in  their  frequency  bands  of  operation  or  suggest  that  UWB  only  be 

 allowed  on  a  licensed  basis.  For  example,  Cingular  and  other  PCS  operators  suggest  that  UWB  devices  be  limited  to  spectrum  above  6  GHz  or  below  1  GHz  for  GPRs  only.  29  The  U.  S.  GPS  Industry  Council 
 asserts  that  it  is  inappropriate  for  communications  applications  of  UWB  to  be  regulated  under  Part  15,  as  these  are  intentional  emitters  that  experience  very  high  peak  powers.  30  ARINC  and  ATA  state  that 
 licensed  UWB  operation  would  provide  protection  to  existing  users  through  frequency  coordination,  but  recognize  that  another  rule  making  proceeding  would  be  required  to  address  the  table  of  frequency 
 allocations.  31  Alloy  states  that  licensing  is  essential  until  UWB  is  found  to  be  non-  interfering.  32  MSSI,  while  a  proponent  of  UWB  operation,  states  that  GPRs  are  inappropriate  for  unlicensed  operation  because 

 21  Fantasma  comments  at  pg.  2. 
 22  AT&  T  comments  at  pg.  5-  6. 
 23  National  Safe  Skies  Alliance  comments  at  pg.  1. 

 24  Siemens  Automotive  ZF  comments  at  pg.  1.  See,  also,  M/  A-  COM  comments  at  pg.  2. 
 25  TDC  reply  comments  at  pg.  4-  19. 
 26  Delphi  comments  at  pg.  7,  Endress  Hauser  comments  at  pg.  2,  Lucent  comments  at  pg.  2,  and  Bosch 
 comments  at  pg.  2  and  reply  comments  at  pg.  1.  27 
 Valeo  Electronics  comments  at  pg.  4.  28 
 Zircon  comments  at  pg.  2.  It  should  be  noted  that  the  Commission  already  declined  to  permit  UWB  devices  to  operate  at  the  Class  A  digital  device  limits  contained  in  47  C.  F.  R.    15.  109(  b).  See  Notice,  op  cit.,  at 

 para.  40.  29 
 See,  for  example,  Cingular  ex  parte  comments  filed  August  20,  2001.  30 
 USGPSIC  comments  at  pg.  29-  30.  31 
 ARINC  and  ATA  joint  comments  at  pg.  9  and  10.  Also,  ATA  et  al  ex  parte  comments  of  6/  6/  01,  5/  18/  01.  32 
 Alloy  reply  comments  at  pg.  6-  9.  Alloy  also  believed  that  the  first  round  of  equipment  to  be  authorized  under  the  rules  would  be  restricted  to  ground  penetrating  radars  and  through-  wall  imaging  systems  employed  mostly 

 by  professionals. 
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 of  their  high  power  level  requirements  and  limited  market.  33 
 16.  Boeing  requests  that  a  new  rule  part  be  established  under  which  UWB  devices  would  be  licensed.  34  Boeing  expresses  concern  that  the  potential  aggregate  impact  of  UWB  devices  is  too 

 significant  to  permit  unless  there  is  sufficient  means  to  control  the  number  of  UWB  devices  in  use.  Under  Boeings  proposal,  the  UWB  manufacturers  would  obtain  from  the  Commission  authority  to  manufacture 
 and  market  a  fixed  number  of  UWB  devices  under  specific  technical  and  operating  conditions,  such  as  limiting  distribution  to  only  public  safety  officials.  Similarly,  Lockheed  states  that  the  Commission  needs 
 to  establish  a  regulatory  regime  that  allows  it  to  limit  the  number  of  devices  that  can  operate  at  one  time  in  the  same  area.  35  Professor  Peha  suggests  a  scheme  where  the  Commission  would  issue  permits  for 
 UWB  devices  and  allow  only  a  fixed  number  of  devices  to  be  introduced  per  year.  Professor  Peha  argues  that  this  approach  would  allow  the  Commission  to  track  usage  and  the  number  of  devices  deployed.  36 
 SIA  and  Sirius  also  request  that  we  implement  some  form  of  blanket  licensing  to  limit  the  number  of  devices  that  can  be  operated  in  one  area.  37  Sirius  believes  that  licensing  enables  potentially  affected 
 services  to  receive  advance  notice  of  the  proposed  UWB  use  and  to  comment  on  those  proposals.  Kohler  opposes  licensing  and  the  use  of  permits  stating  that  the  Commission  does  not  have  the  authority  to 
 implement  this  method  of  licensing.  Kohler  argues  that  such  an  approach  would  create  mutual  exclusivity  by  designating  the  number  of  UWB  devices  that  could  be  authorized  per  year  and  would  not  comport  with 
 47  U.  S.  C.  309(  j).  38 
 17.  Based  on  our  review  of  the  record,  we  continue  to  believe  that  UWB  technology  offers  significant  benefits  for  public  safety,  businesses  and  consumers.  We  anticipate  that  the  authorization  of 

 UWB  technology  will  create  new  business  opportunities  for  manufacturers,  distributors  and  vendors  that  will  enhance  competition  and  the  economy.  We  also  find  that  the  use  of  this  technology  would  promote 
 spectrum  efficiency  by  sharing  frequencies  with  other  services  without  causing  interference.  We  also  note  that  authorization  of  UWB  is  consistent  with  Section  7  of  the  Communications  Act  of  1934,  as 
 amended,  which  requires  the  Commission  "  to  encourage  the  provision  of  new  technologies  and  services  to  the  public."  39 

 18.  We  are  cognizant;  however,  that  the  substantial  benefits  of  UWB  technology  could  be  outweighed  if  UWB  devices  were  to  cause  interference  to  licensed  services  and  other  important  radio 
 operations.  Our  analysis  of  the  record  and  the  various  technical  studies  submitted  indicates  that  UWB  devices  can  be  permitted  to  operate  without  causing  harmful  interference  if  appropriate  technical 
 standards  and  operational  restrictions  are  applied  to  their  use.  In  this  regard,  we  are  establishing  different  technical  standards  and  operating  restrictions  for  different  types  of  UWB  equipment  based  on  their 
 potential  to  cause  interference.  As  discussed  below,  we  are,  inter  alia,  adopting  emission  limits  for  UWB  that  are  generally  more  stringent  than  those  imposed  on  other  Part  15  devices  and  limiting  the  frequency 
 range  below  which  certain  UWB  products  will  be  permitted  to  operate.  We  believe  that  this  combination  of  technical  standards  and  operational  restrictions  will  enable  UWB  devices  to  coexist  with  the  authorized 

 33  MSSI  comments  at  pg.  12.  MSSI  subsequently  cosigned  the  ATA  et  al  ex  parte  comments  of  6/  6/  01, 
 5/  18/  01.  34 
 Boeing  comments  at  pg.  13-  14.  35 
 Lockheed  reply  comments  at  pg.  5.  Lockheed  suggested  that  unlicensed  operation  could  be  considered  only  on  frequencies  where  there  is  no  reasonable  interference  concerns  for  safety  services. 

 36  Prof.  Peha  comments  at  pg.  6. 
 37  SIA  reply  comments  at  pg.  5.  Sirius  reply  comments  at  pg.  3,  11  and  18. 
 38  Kohler  reply  comments  at  pg.  5-  6. 
 39  See  47  U.  S.  C.    157(  a)  (1998). 
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 radio  services  without  the  risk  of  harmful  interference. 
 19.  We  also  continue  to  believe  that  unlicensed  operation  under  Part  15  of  our  rules  is  the  most  appropriate  manner  in  which  to  authorize  UWB  devices  at  this  time.  These  products,  in  general,  will 

 operate  with  very  low  power  making  licensing  unnecessary.  In  this  regard,  we  are  not  permitting  UWB  devices  to  be  employed  in  higher  power  applications,  such  as  wide-  area  mobile  radio  services.  Instead, 
 we  are  adopting  emission  limits  that  are  designed  to  ensure  that  harmful  interference  to  the  authorized  radio  services  is  minimized,  including  interference  from  the  cumulative  effect  of  multiple  UWB  devices. 
 We  also  are  placing  several  restrictions  on  how  and  where  UWB  devices  may  be  operated  to  ensure  that  harmful  interference  is  not  caused  by  these  operations.  We  do  not  believe  that  requiring  licensing  is 
 appropriate.  However,  we  are  implementing  a  coordination  requirement  for  imaging  devices,  as  requested  by  NTIA.  40  We  also  do  not  believe  that  it  is  practical  to  limit  the  number  of  devices  being 
 produced  by  a  manufacturer.  We  anticipate  that  many  of  these  devices  will  be  small  or  portable  and  therefore  any  such  limits  would  not  necessarily  limit  the  number  of  transmitters  concentrated  in  any 
 specific  location.  We  believe  that  regulating  UWB  through  power  restrictions  and  other  technical  requirements  is  sufficient  and  has  worked  successfully  for  other  Part  15  devices.  Accordingly,  we  see  no 
 benefits,  commensurate  with  the  added  costs  to  the  public  and  manufacturers,  from  requiring  individual  operators  to  obtain  a  license  or  from  attempting  to  limit  the  yearly  production  of  individual  UWB 
 manufacturers.  Thus,  we  are  promulgating  the  regulations  for  UWB  operation  under  Part  15  of  our  rules. 
 20.  For  regulatory  purposes,  we  have  categorized  UWB  devices  into  three  types:  1)  imaging  systems  (including  GPRs),  2)  vehicular  radar  systems,  and  3)  communications  and  measurement  systems. 

 We  believe  that  these  categories  provide  a  logical  way  to  address  the  various  technical  characteristics  of  the  different  applications.  Most  imaging  systems  emit  energy  that  is  largely  absorbed  by  the  material 
 against  which  they  are  placed.  A  GPR  operates  only  when  in  contact  with  or  within  close  proximity  to  the  ground  for  the  purpose  of  detecting  or  obtaining  the  images  of  buried  objects.  Imaging  systems  can  be 
 used  to  detect  objects  within  or  on  the  other  side  of  walls.  A  wall  imaging  system  is  designed  to  detect  the  location  of  objects  contained  within  a  wall,  such  as  a  concrete  structure,  the  side  of  a  bridge,  or  the 
 wall  of  a  mine.  A  through-  wall  imaging  system  detects  the  location  or  movement  of  persons  or  objects  that  are  located  on  the  other  side  of  a  structure  such  as  a  wall  or  a  ceiling.  A  surveillance  system  is  a 
 stationary  radar  system  used  for  security  purposes  by  establishing  an  RF  perimeter  and  detecting  the  movement  of  persons  or  objects  within  that  perimeter.  Vehicular  radar  systems  are  able  to  detect  the 
 location  and  movement  of  objects  near  a  vehicle,  enabling  features  such  as  near  collision  avoidance,  improved  airbag  activation,  and  suspension  systems  that  better  respond  to  road  conditions. 
 Communications  and  measurement  systems  consist  of  indoor  and  hand  held  devices  that  can  encompass  a  wide  variety  of  applications  including  high-  speed  home  and  business  networking  devices.  41  The  term 
 hand  held  devices,  as  used  in  this  Order,  refers  to  portable  devices,  such  as  a  lap  top  computer  or  a  PDA,  that  are  primarily  hand  held  while  being  operated  and  that  do  not  employ  a  fixed  infrastructure 
 when  operating  outdoors. 
 21.  We  have  established  different  standards  for  these  devices  based  on  their  individual  operating  characteristics  and  potential  for  causing  interference  to  the  authorized  radio  services.  We 

 recognize  that  our  initial  restrictions  on  applications,  operating  frequencies  and  emission  levels  may  limit  some  UWB  applications.  However,  we  believe  that  we  should  be  cautious  until  we  have  gained  further 
 experience  with  this  technology.  Once  additional  experience  has  been  gained  with  UWB  operation,  we  may  consider  whether  more  flexible  standards  are  appropriate.  Within  their  permitted  bands  of  operation, 

 40  See  letter  of  February  13,  2002,  from  William  T.  Hatch,  Associate  Administrator,  Office  of  Spectrum 
 Management,  U.  S.  Department  of  Commerce  to  Edmond  J.  Thomas,  Chief,  Office  of  Engineering  and  Technology,  FCC.  A  copy  of  the  letter  is  on  file  in  this  proceeding. 

 41  Indoor  systems,  because  of  the  additional  shielding  provided  by  building  walls,  are  able  to  operate  with 
 slightly  higher  levels  of  unwanted  emissions. 
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 UWB  devices  may  operate  at  the  emission  limits  specified  in  47  C.  F.  R.    15.209.  The  other  basic  operating  parameters  for  these  devices  are  summarized  below: 
   Imaging  Systems:  Imaging  systems  include  GPRs,  wall  imaging  systems,  through-  wall  imaging  systems,  surveillance  systems  and  medical  systems.  All  imaging  systems  are  subject 
 to  coordination  with  NTIA  through  the  FCC.  NTIA  has  indicated  that  coordination  will  be  as  expeditious  as  possible,  requiring  no  longer  than  15  business  days,  and  may  be  expedited  in 
 emergency  situations.  Except  for  medical  imaging  systems,  the  operators  of  imaging  devices  must  be  eligible  for  licensing  under  Part  90  of  our  rules.  The  standards  for  the  different 
 imaging  systems  are  as  follows: 
   Ground  Penetrating  Radar  Systems:  GPRs  must  be  operated  with  their  10  dB  bandwidth  below  960  MHz  or  in  the  frequency  band  3.1-  10.6  GHz.  GPRs  operate  only 
 when  in  contact  with,  or  within  close  proximity  of,  the  ground  for  the  purpose  of  detecting  or  obtaining  the  images  of  buried  objects.  The  energy  from  the  GPR  is 
 intentionally  directed  down  into  the  ground  for  this  purpose.  Operation  is  restricted  to  law  enforcement,  fire  and  emergency  rescue  organizations,  42  to  scientific  research 
 institutions,  to  commercial  mining  companies,  and  to  construction  companies. 
   Wall  Imaging  Systems:  Wall  imaging  systems  must  be  operated  with  their  10  dB  bandwidth  below  960  MHz  or  in  the  frequency  band  3.1-  10.  6  GHz.  Wall-  imaging 
 systems  are  designed  to  detect  the  location  of  objects  contained  within  a  wall,  such  as  a  concrete  structure,  the  side  of  a  bridge,  or  the  wall  of  a  mine.  Operation  is  restricted  to 
 law  enforcement,  fire  and  emergency  rescue  organizations,  to  scientific  research  institutions,  to  commercial  mining  companies,  and  to  construction  companies. 

   Through-  wall  Imaging  Systems:  These  systems  must  be  operated  with  their  10  dB  bandwidth  below  960  MHz  or  in  the  frequency  band  1.99-  10.  6  GHz.  Through-  wall 
 imaging  systems  detect  the  location  or  movement  of  persons  or  objects  that  are  located  on  the  other  side  of  a  structure  such  as  a  wall.  Operation  is  limited  to  law  enforcement,  fire 
 and  emergency  rescue  organizations. 
   Surveillance  Systems:  Although  technically  these  devices  are  not  imaging  systems,  for  regulatory  purposes  they  will  be  treated  in  the  same  way  as  through-  wall  imaging 
 systems  used  by  police,  fire  and  rescue  organizations  and  will  be  permitted  to  operate  with  their  10  dB  bandwidth  in  the  frequency  band  1.99-  10.6  GHz.  Surveillance  systems 
 operate  as  security  fences  by  establishing  a  stationary  RF  perimeter  field  and  detecting  the  intrusion  of  persons  or  objects  in  that  field.  Operation  is  limited  to  law  enforcement, 
 fire  and  emergency  rescue  organizations,  to  public  utilities  and  to  industrial  entities.  43 
   Medical  Systems:  These  devices  must  be  operated  with  their  10  dB  bandwidth  in  the  frequency  band  3.1-  10.  6  GHz.  A  medical  imaging  system  is  used  to  detect  the  location 
 or  movement  of  objects  within  the  body  of  a  person  or  animal.  Operation  must  be  at  the  direction  of,  or  under  the  supervision  of,  a  licensed  health  care  practitioner. 

 42  As  used  in  this  Order,  law  enforcement,  fire  and  emergency  rescue  organizations  refers  to  parties  eligible  to 
 obtain  a  license  from  the  FCC  under  the  eligibility  requirements  specified  in  Section  90.  20(  a)(  1)  of  this  chapter.  43 
 As  used  in  this  Order,  the  reference  to  public  utilities  and  industrial  entities  refers  to  the  manufacturers  licensees,  petroleum  licensees  or  power  licensees  defined  in  47  C.  F.  R.    90.  7. 
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   Vehicular  Radar  Systems:  Provides  for  the  operation  of  vehicular  radar  systems  using  directional  antennas  on  terrestrial  transportation  vehicles  provided  the  center  frequency  of  the 
 emission  and  the  frequency  at  which  the  highest  radiated  emission  occurs  are  greater  than  24.075  GHz.  The  -10  dB  bandwidth  must  be  between  22  and  29  GHz.  These  devices  are  able 
 to  detect  the  location  and  movement  of  objects  near  a  vehicle,  enabling  features  such  as  near  collision  avoidance,  improved  airbag  activation,  and  suspension  systems  that  better  respond 
 to  road  conditions.  Attenuation  of  the  emissions  below  24  GHz  is  required  above  the  horizontal  plane  in  order  to  protect  space  borne  passive  sensors  operating  in  the  23.6-  24.0 
 GHz  band. 
   Communications  and  Measurement  Systems:  Provides  for  use  of  a  wide  variety  of  other  UWB  devices,  such  as  high-  speed  home  and  business  networking  devices  as  well  as  storage 
 tank  measurement  devices  under  Part  15  of  the  Commissions  rules  subject  to  certain  frequency  and  power  limitations.  The  devices  must  operate  with  their  10  dB  bandwidth  in 
 the  frequency  band  3.1-  10.6  GHz.  The  equipment  must  be  designed  to  ensure  that  operation  can  only  occur  indoors  or  it  must  consist  of  hand  held  devices  that  may  be  employed  for  such 
 activities  as  peer-  to-  peer  operation.  The  limits  on  unwanted  emissions  are  more  stringent  for  hand  held  devices  than  they  are  for  indoor-  only  systems. 

 B.  UWB  Definition 
 22.  Proposal.  In  the  Notice,  the  Commission  proposed  to  adopt  a  modified  version  of  the  UWB  definition  established  by  the  OSD/  DARPA  UWB  radar  review  panel.  44  Specifically,  the  Commission 

 proposed  to  define  a  UWB  device  as  any  device  where  the  fractional  bandwidth  is  greater  than  0.25  or  occupies  1.5  GHz  or  more  of  spectrum.  45  The  formula  proposed  by  the  Commission  for  calculating 
 fractional  bandwidth  is  2(  fH-  fL)/(  fH+  fL)  where  fH  is  the  upper  frequency  of  the  10  dB  emission  point  and  fL  is  the  lower  frequency  of  the  10  dB  emission  point.  The  center  frequency  of  the  transmission  was 
 defined  as  the  average  of  the  upper  and  lower  10  dB  points,  i.  e.,  (fH+  fL)/  2.  46  The  Commission  proposed  to  base  its  modified  definition  of  an  UWB  device  on  10  dB  bandwidth,  rather  than  the  20  dB  bandwidth 
 used  by  OSD/  DARPA,  because  under  the  Part  15  limits,  UWB  devices  operate  so  close  to  the  noise  floor  that  in  many  cases  it  may  not  be  possible  to  measure  the  20  dB  bandwidth.  The  Commission  also 
 proposed  that  the  bandwidth  be  determined  using  the  antenna  that  is  designed  to  be  used  with  the  UWB  device.  Comments  were  requested  on:  1)  the  proposed  definition;  2)  whether  the  fractional  bandwidth 
 should  be  changed  to  account  for  the  narrower  bandwidth  that  would  be  measured  using  the  10  dB  emission  points  instead  of  the  20  dB  points;  3)  whether  we  should  use  some  other  method  to  determine 
 the  emission  bandwidth,  such  as  a  calculated  bandwidth  based  on  pulse  width;  4)  whether  we  should  define  UWB  devices  as  limited  to  devices  that  solely  use  pulsed  emissions  where  the  bandwidth  is 
 directly  related  to  the  pulse  width;  47  and  5)  whether  extremely  high  speed  data  systems  that  comply  with  the  UWB  bandwidth  requirements  only  because  of  the  high  data  rate  employed,  as  opposed  to  meeting  the 
 definition  solely  from  the  narrow  pulse  width,  should  be  permitted.  In  the  Notice,  the  Commission  indicated  it  would  pursue  a  conservative  initial  approach  until  more  experience  was  gained  with  UWB 

 44  Assessment  of  Ultra-  Wideband  (UWB)  Technology,  OSD/  DARPA,  Ultra-  Wideband  Radar  Review  Panel, 
 R-  6280,  Office  of  the  Secretary  of  Defense,  Defense  Advanced  Research  Projects  Agency,  July  13,  1990.  45 
 Under  the  proposed  definition  of  an  UWB  device,  the  1.5  GHz  maximum  bandwidth  limit  would  only  apply  where  the  center  frequency  is  greater  than  6  GHz. 

 46  In  some  UWB  systems,  there  is  no  clear  center  frequency  as  with  other  modulation  techniques,  such  as  AM 
 and  FM.  Furthermore,  the  shape  of  the  transmitted  spectrum  may  be  significantly  modified  by  the  frequency  response  of  the  antenna  such  that  even  the  carrier  frequency,  where  employed,  may  not  represent  the  center 

 frequency.  47 
 Other  types  of  modulation,  such  as  linear  sweep  FM,  could  be  employed  to  produce  UWB  equipment. 
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 operations. 
 23.  Comments.  The  commenting  parties  generally  supported  basing  the  definition  of  UWB  either  on  a  fractional  bandwidth  or  some  minimum  emission  bandwidth.  48  They  disagreed,  however,  on 

 the  specific  values  that  should  be  applied  for  a  device  to  be  defined  as  UWB.  There  was  also  disagreement  among  the  parties  with  regard  to  limiting  the  modulation  to  pulsed  modulation,  and 
 requiring  that  the  bandwidth  be  directly  related  to  the  narrow  pulse  width  instead  of  the  data  rate.  There  were  no  objections  to  determining  the  bandwidth  of  the  UWB  emission  using  the  antenna  designed  to  be 
 employed  with  the  UWB  transmitter.  49 
 24.  A  number  of  commenting  parties  supported  the  proposal  in  the  Notice  to  use  the  10  dB  emission  points  to  determine  the  fractional  bandwidth.  Bosch,  for  example,  stated  that  the  definition  of 

 UWB  should  be  based  solely  on  bandwidth  using  the  10  dB  emission  points.  50  It  stated  that  the  20  dB  emission  points  were  too  near  the  noise  floor  to  be  measured  reliably.  Bosch  also  noted  that  the  20  dB 
 emission  points  would  be  ambiguous  as  such  points  appear  on  both  the  fundamental  lobe  and  the  side  lobes.  Similar  concerns  about  use  of  the  20  dB  emission  points  were  echoed  by  Valeo,  51  Kohler,  52  and 
 others. 
 25.  Objections  to  the  use  of  the  10  dB  emission  points  to  determine  the  fractional  bandwidth  were  filed  by  NBAA.  It  stated  that  the  10  dB  fractional  bandwidth  was  arbitrary  and  asserts  that  it 

 would  ignore  emission  components  that  could  account  for  peak  powers  of  hundreds  of  watts.  53  NBAA  suggests  that  the  bandwidth  of  the  device  be  more  than  5  percent  of  its  center  frequency.  AOPA  requests 
 that  the  bandwidth  be  based  on  the  20  dB  points  stating  that  emission  levels  vary  too  much  to  use  the    10  dB  points.  54  ARRL  requests  that  the  bandwidth  be  determined  using  the  23  dB  points  believing  that 
 this  would  be  consistent  with  other  Commission  regulations  on  spurious  and  out-  of-  band  emissions.  55 
 26.  Several  parties  requested  that  the  fractional  bandwidth  of  0.25  and  minimum  bandwidth  of  1.5  GHz  limit  be  reduced  from  that  proposed  in  the  Notice  due  to  the  use  of  10  dB  rather  than  the  20 

 dB  emission  points.  56  SME  and  Valeo,  for  example,  requested  a  fractional  bandwidth  of  around  0.  17  and 
 48  See,  e.  g.,  the  comments  of  Aether  Wire  and  Location  at  pg.  7,  ANRO  at  pg.  1,  CSSIP  at  pg.  1,  Delphi  at  pg. 
 10,  Endress  Hauser  at  pg.  3,  Lucent  at  pg.  5,  M/  A-  Com  at  pg.  1,  Bosch  at  pg.  2,  TDC  at  pg.  21,  and  Zircon  at  pg.  2.  We  have  used  the  term  minimum  bandwidth  in  this  proceeding  to  reference  the  bandwidth  above  which  a  product 

 qualifies  as  a  UWB  device  regardless  of  its  fractional  bandwidth.  49 
 As  noted  by  Aether  Wire  and  Location,  the  antenna  is  an  integral  part  of  the  system  that  affects  the  radiated  bandwidth  and  the  phase  response.  Aether  Wire  and  Location  comments  at  pg.  7. 

 50  Bosch  comments  at  pg.  2-  3  and  reply  comments  at  pg.  1-  2. 
 51  Valeo  comments  at  pg.  4. 
 52  Kohler  comments  at  pg.  4. 
 53  The  limits  being  adopted  in  this  proceeding  do  not  permit  peak  emissions  approaching  this  amplitude. 
 54  AOPA  comments  at  pg.  4. 
 55  ARRL  comments  at  pg.  18.  It  should  be  noted  that  these  emission  points  are  representative  of  the 
 attenuation  requirements  for  the  authorized  radio  services  where  the  radiated  emission  levels  are  powerful  enough  to  be  easily  measured. 

 56  ARRL  requested  that  a  minimum  frequency  bandwidth  be  applied  to  the  UWB  definition  since  a  0.25 
 fractional  bandwidth  would  not  result  in  a  very  wide  emission  for  a  system  operating  at,  say,  3.5  MHz.  See  ARRL  comments  at  pg.  13.  However,  ARRL  did  not  suggest  a  lower  limit.  We  did  not  address  this  issue  in  this  proceeding 

 since  UWB  systems,  other  than  GPRs  and  certain  imaging  systems  are  required  to  operate  in  considerably  higher  frequency  ranges.  GPRs  and  imaging  systems  need  to  operate  at  frequencies  higher  than  3.5  MHz  in  order  to  obtain 
 the  needed  object  resolution. 
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 an  upper  bandwidth  limit  of  one  gigahertz.  57  Siemens  requests  that  the  fractional  bandwidth  be  reduced  to  0.15  with  a  1  GHz  upper  bandwidth  limit.  58  Bosch  requests  a  fractional  bandwidth  of  0.15-  0.20  and  a 
 minimum  bandwidth  of  one  to  1.5  gigahertz.  59  ANRO  and  Kohler  request  a  fractional  bandwidth  of  0.20.  60  Daimler  Chrysler  requested  an  upper  bandwidth  limit  of  one  gigahertz.  61 

 27.  Delphi  requested  that  a  minimum  bandwidth  of  500  MHz  be  used  to  define  UWB,  regardless  of  center  frequency,  and  that  all  forms  of  modulation  be  permitted.  62  It  added  that  absent  such 
 changes  manufacturers  producing  radar  devices  under  the  current  regulations  would  be  disadvantaged  because  they  would  not  be  permitted  to  operate  their  equipment  within  the  restricted  bands.  M/  A-  Com 
 objected  to  Delphis  request  stating  that  the  Commission  is  not  promoting  the  operation  of  narrowband  systems  in  restricted  bands.  63  On  the  other  hand,  MSSI  stated  that  UWB  systems  should  be  permitted 
 with  bandwidths  as  low  as  200  MHz,  indicating  that  UWB  devices  could  be  constructed  with  bandwidths  as  narrow  as  20-  30  MHz.  64 

 28.  With  regard  to  the  use  of  modulation  types  other  than  pulsed  or  impulse  emissions,  AOPA  expressed  concern  that  such  proposals  to  expand  the  definition  of  UWB  would  open  the  door  for 
 additional  types  of  devices.  65  These  additional  devices  could  have  different  interference  characteristics.  Similarly,  TDC  did  not  believe  that  all  devices  above  a  certain  minimum  fractional  bandwidth  or  upper 
 bandwidth  limit  should  be  characterized  as  UWB,  stating  that  most  of  the  benefits  of  UWB  come  from  having  very  few  cycles  within  the  pulse  envelopes,  not  the  duration  of  the  pulse  envelope  itself.  66  TDC 
 also  raised  concerns  that  minimal  information  exists  regarding  the  interference  potential  and  applicable  measurement  procedures  for  stepped  and  swept  frequency  systems.  67  Endress  Hauser  and  USGPSIC  also 
 expressed  concerns  about  permitting  the  operations  of  linear  sweep  systems  and  chirped  systems  respectively.  68  On  the  other  hand,  ARRL  agreed  with  Delphi  that  all  modulation  types  should  be 
 permitted  provided  proper  peak,  average  and  power  spectral  density  limits  are  met.  69  CSSIP  70  ,  Krohne  71  ,  Siemens  72  and  Valeo  73  specifically  requested  that  stepped  frequency  or  swept  frequency  systems  be 

 57  SME  comments  at  pg.  2  and  4.  Valeo  comments  at  pg.  4. 
 58  Siemens  comments  are  pg.  2. 
 59  Bosch  comments  at  pg.  2-  3  and  reply  comments  at  pg.  1-  2. 
 60  ANRO  comments  at  pg.  1.  Kohler  comments  at  pg.  4. 
 61  Ex  parte  filing  of  Daimler  Chrysler  on  July  31,  2001. 
 62  Delphi  comments  at  pg.  9-  17.  Delphi  later  amended  its  proposal  to  include  only  pseudo-  noise  direct 
 sequence  binary  phase  shift  key  type  of  modulation.  Delphi  ex  parte  filing  of  July  13,  2001.  63 
 M/  A-  Com  reply  comments  at  pg.  2.  64 
 MSSI  comments  at  pg.  15.  65 
 AOPA  reply  comments  at  pg.  10-  11.  66 
 TDC  comments  at  pg.  21.  67 
 TDC  comments  at  pg.  25.  68 
 Endress  Hauser  comments  at  pg.  3-  4  and  USGPSIC  comments  at  pg.  2  of  Attachment  A.  69 
 ARRL  reply  comments  at  pg.  9.  70 
 CSSIP  comments  at  pg.  1.  71 
 Krohne  comments  at  pg.  4.  72 
 Siemens  comments  at  pg.  2.  73 
 Valeo  comments  at  pg.  5. 
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 permitted  under  the  UWB  definition.  Krohne  argued  that  there  is  sufficient  information  on  measurement  procedures  and  emission  limits  for  these  devices. 
 29.  Bosch  stated  that  basing  the  definition  on  the  use  of  a  narrow  pulse  width  to  achieve  a  wide  emission  bandwidth  could  impede  the  development  of  novel  pulse  or  modulation  schemes,  including 
 high-  speed  data  systems.  74  XSI  stated  that  we  should  include  extremely  high-  speed  data  systems  that  comply  only  because  of  the  high-  speed  data  rate  and  not  because  of  narrow  pulse  width.  75  XSI  stated 
 that  the  threat  of  harmful  interference  depends  primarily  on  the  average  and  peak  emissions  and  the  location  of  significant  spectral  lines  and  is  affected  little,  if  at  all,  by  the  nature  of  the  modulating  signal. 
 AOPA  objected  indicating  that  other  modulation  techniques,  such  as  chirping,  are  likely  to  have  different  interference  potential  characteristics.  76 

 30.  Discussion.  We  are  adopting  our  proposal  to  use  the  10  dB  emission  points  to  determine  the  bandwidth  and  the  center  frequency  of  the  UWB  emission.  As  pointed  out  by  Bosch  and 
 others,  the  20  dB  emission  points  could  be  so  near  the  noise  floor  that  making  accurate  measurements  would  be  difficult  or  impractical.  Similarly,  it  would  be  impractical  to  specify  the  23  dB  points 
 recommended  by  ARRL.  In  addition,  we  agree  that  the  minimum  required  fractional  bandwidth  should  be  reduced  given  that  the  use  of  the  10  dB  bandwidth  measurement  points  will  result  in  a  smaller 
 measured  bandwidth.  77  Accordingly,  we  are  reducing  the  10  dB  fractional  bandwidth  from  0.25  to  0.20.  For  this  same  reason,  we  also  are  reducing  the  minimum  bandwidth  limit  from  the  1.5  gigahertz  proposed 
 in  the  Notice  to  a  limit  of  500  megahertz  for  UWB  devices.  78  A  minimum  bandwidth  limit  of  500  megahertz  should  accommodate  most  of  the  proponents  in  this  proceeding.  While  some  parties  have 
 suggested  that  we  could  eliminate  all  restrictions  on  fractional  bandwidth  and  minimum  bandwidth,  we  disagree.  In  the  absence  of  a  minimal  bandwidth  requirement,  many  devices  could  be  designed  to  operate 
 in  restricted  bands  even  though  they  have  no  need  to  do  so.  For  example,  devices  such  as  radio  control  toys  typically  employ  bandwidths  of  25  kHz  or  less  and  there  are  ample  provisions  to  operate  such 
 devices  outside  of  the  restricted  bands. 
 31.  We  also  do  not  believe  that  there  is  any  justification  for  reducing  the  minimum  bandwidth  to  200  MHz,  as  sought  by  MSSI.  One  of  the  major  regulations  being  addressed  in  this 

 proceeding  is  the  operation  of  Part  15  devices  in  the  restricted  bands  described  in  47  C.  F.  R.    15.205.  We  are  amending  the  rules  in  this  Report  and  Order  to  permit  UWB  devices  to  emit  in  certain  restricted  bands 
 because  the  bandwidths  employed  by  those  systems  are  so  wide  that  they  have  difficulty  finding  spectrum  to  operate  without  transmitting  in  one  or  more  of  the  restricted  bands.  We  do  not  find  a  similar  difficulty 
 finding  200  MHz  of  contiguous  spectrum  outside  of  the  restricted  bands.  For  example,  unlicensed  Part  15  operation  at,  or  higher  than,  the  emission  levels  being  permitted  for  UWB  devices  currently  is  permitted 
 in  the  frequency  bands  1722.2-  2200  MHz,  2900-  3260  MHz,  3359-  3600  MHz,  5150-  5350  MHz,  5460-  7250  MHz,  etc.  Further,  Part  15  devices  operating  in  these  bands  could  be  employed  for  any  purpose 
 without  having  to  comply  with  the  additional  standards  that  are  being  adopted  for  UWB  devices.  At  this  time,  we  do  not  wish  to  open  the  restricted  bands  for  operation  by  any  Part  15  device  that  can  operate 

 74  Bosch  comments  at  pg.  3. 
 75  XSI  comments  at  pg.  8. 
 76  AOPA  comments  at  pg.  5. 
 77  The  fractional  bandwidth  value  of  0.25,  or  25  percent,  was  established  by  the  OSD/  DARPA  UWB  radar 
 review  panel  based  on  the  use  of  a  20  dB  emission  bandwidth.  78 
 As  noted,  UWB  devices  would  be  required  to  have  a  10  dB  fractional  bandwidth  of  at  least  0.20  or  a  10  dB  bandwidth  of  at  least  500  MHz.  The  effect  of  this  change  is  that  UWB  systems  with  a  center  frequency  greater 

 than  2.5  GHz  need  to  have  a  10  dB  bandwidth  of  at  least  500  megahertz  while  UWB  systems  operating  with  a  center  frequency  below  2.5  GHz  need  to  have  a  fractional  bandwidth  of  at  least  0.20. 
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 satisfactorily  between  the  restricted  bands.  Accordingly,  we  are  limiting  the  minimum  bandwidth  limit  to  500  MHz.  Once  additional  experience  has  been  gained  with  UWB  operation,  we  may  revisit  these  values. 
 32.  We  agree  with  Bosch  and  XSI  that  transmission  systems  should  not  be  precluded  from  the  UWB  definition  simply  because  the  bandwidth  of  the  emission  is  due  to  a  high  speed  data  rate  instead 
 of  the  width  of  the  pulse  or  impulse.  We  also  agree  with  ARRL  and  Delphi  that  various  modulation  types  should  be  permitted  as  long  as  the  products  comply  with  all  of  the  technical  standards  that  are  being 
 adopted  in  this  proceeding.  Thus,  as  long  as  the  transmission  system  complies  with  the  fractional  bandwidth  or  minimum  bandwidth  requirements  at  all  times  during  its  transmission,  we  agree  that  it 
 should  be  permitted  to  operate  under  the  UWB  regulations.  We  recognize  that  this  may  preclude  certain  types  of  modulations,  such  as  swept  frequency  (e.  g.,  FMCW),  stepped  frequency  or  frequency  hopping 
 systems.  The  current  measurement  procedures  require  that  measurements  of  swept  frequency  devices  be  made  with  the  frequency  sweep  stopped.  79  The  sweep  is  stopped  because  no  measurement  procedures 
 have  been  proposed  or  established  for  swept  frequency  devices  nor  has  the  interference  aspects  of  swept  frequency  devices  been  evaluated  based  on  the  different  measurement  results  that  would  be  obtained  from 
 measurements  taken  with  the  sweep  active.  Similarly,  measurements  on  a  stepped  frequency  or  frequency  hopping  modulated  system  are  performed  with  the  stepping  sequence  or  frequency  hop  stopped.  With  the 
 sweep,  step  function  or  hopping  stopped,  it  is  unlikely  that  swept  frequency  (linear  FM  or  FMCW)  or  stepped  frequency  modulated  emissions  would  comply  with  the  fractional  bandwidth  or  minimum 
 bandwidth  requirements.  It  also  is  unlikely  that  frequency  hopping  systems  would  comply  unless  an  extremely  wide  bandwidth  hopping  channel  is  employed.  80 

 C.  Frequency  Bands  and  Operational  Requirements  for  UWB  Devices 
 33.  Proposal.  In  the  Notice,  the  Commission  indicated  that  it  considered  a  number  of  factors  in  addressing  which  frequency  bands  should  be  made  available  for  UWB  devices.  First  is  the  need  to 

 protect  from  interference  the  vitally  important  and  critical  safety  systems  operating  in  the  restricted  frequency  bands,  including  GPS  operations.  Second,  there  are  a  broad  variety  of  potential  applications  for 
 UWB  technology,  each  of  which  has  unique  spectrum  attributes  and  requirements.  Third,  various  regions  of  the  spectrum  have  different  propagation  characteristics.  To  realize  the  full  benefits  of  this  technology, 
 the  Commission  indicated  that  it  should  establish  as  few  restrictions  as  possible  on  UWB  operating  frequencies,  except  as  necessary  to  protect  existing  services  against  interference. 

 34.  The  Commission  noted  that  it  had  a  number  of  concerns  about  generally  permitting  the  operation  of  UWB  devices  in  the  region  of  the  spectrum  below  approximately  2  GHz.  This  is  perhaps  the 
 most  heavily  occupied  region  of  the  spectrum  and  is  used  for  public  safety,  aeronautical  and  maritime  navigation  and  communications,  AM,  FM  and  TV  broadcasting,  private  and  commercial  mobile 
 communications,  medical  telemetry,  amateur  communications,  and  GPS  operations.  Further,  41  of  the  64  restricted  frequency  bands  are  at  or  below  2  GHz,  not  counting  the  TV  broadcast  bands.  Of  particular 
 concern  is  the  impact  of  any  potential  interference  to  the  GPS  band  at  1559-  1610  MHz.  The  Commission  also  expressed  concern  about  interference  to  any  additional  frequencies  allocated  to  GPS,  e.  g.,  the 
 planned  L5  frequency  in  the  960-  1215  MHz  band.  GPS  will  be  increasingly  relied  upon  for  air  navigation  and  safety,  and  is  a  cornerstone  for  improving  the  efficiency  of  the  air  traffic  system.  GPS  also  may  be 
 used  by  commercial  mobile  radio  E-  911  services  to  enable  police  and  fire  departments  to  quickly  locate  individuals  in  times  of  emergency.  Moreover,  businesses  and  consumers  are  now  employing  GPS  for 
 various  applications,  such  as  for  navigation  by  automobiles,  boats  and  other  vehicles,  surveying,  hiking, 
 79  See  47  C.  F.  R.  15.31(  c). 
 80  We  note  that  NTIA  recently  agreed  that  a  waiver  could  be  issued  to  Krohne  to  permit  the  Part  15  operation 
 of  its  level  measuring  radar  system  in  steel  tanks.  This  should  alleviate  Krohnes  concerns  in  the  UWB  proceeding.  See  letter  of  September  5,  2001,  from  William  Hatch  of  NTIA  to  Bruce  Franca,  Acting  Chief,  OET,  FCC.  See,  also, 

 letter  of  October  26,  2001,  from  Bruce  A.  Franca  to  Fish  &  Richardson  granting  Krohne  its  waiver  request. 
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 and  geologic  measurements.  Therefore,  any  harmful  interference  to  GPS  could  have  a  serious  detrimental  impact  on  public  safety,  businesses  and  consumers.  In  addition,  propagation  losses  are  not  as  great  below 
 2  GHz,  and  services  in  this  region  of  the  spectrum  tend  to  employ  omnidirectional  antennas  that  do  not  discriminate  against  undesired  signals.  These  factors  tend  to  increase  the  risks  of  interference  below  2 
 GHz. 
 35.  In  light  of  these  factors,  the  Commission  expressed  concern  about  the  operation  of  UWB  devices,  except  for  GPRs  and  possibly  through-  wall  imaging  devices,  in  the  region  of  the  spectrum  below 

 approximately  2  GHz.  Comments  were  invited  on  whether  UWB  devices  should  be  restricted  from  operating  on  frequencies  below  2  GHz,  and  the  impact  such  a  restriction  would  have  on  the  potential 
 applications  for  UWB  technology.  Comments  also  were  requested  as  to  the  precise  frequency  below  which  the  operation  of  UWB  devices  may  need  to  be  restricted.  81  For  example,  should  operation  be 
 restricted  below  the  GPS  band  at  1610  MHz,  or  below  the  restricted  band  at  1718.  8  -  1722.2  MHz,  or  below  the  Personal  Communication  Service  band  at  1850  -  1990  MHz,  or  below  some  other  frequency? 

 36.  Notwithstanding  the  above  concerns,  the  Commission  noted  that  GPRs  must  operate  at  frequencies  in  the  region  below  2  GHz  in  order  to  obtain  the  penetration  depth  and  resolution  necessary  to 
 detect  and  obtain  the  images  of  buried  objects.  It  noted,  however,  that  the  risk  of  interference  from  GPRs  is  low  because  the  majority  of  their  energy  is  directed  into  the  ground.  In  addition,  GPRs  are  expected  to 
 have  a  low  proliferation  and  usually  operate  at  infrequent  intervals.  Accordingly,  the  Commission  proposed  to  allow  GPRs  to  operate  in  any  part  of  the  spectrum.  It  proposed  to  define  a  GPR  as  an  UWB 
 device  that  is  designed  to  operate  only  when  in  contact  with,  or  in  close  proximity  to  (i.  e.,  within  1  meter),  the  ground  for  the  purpose  of  detecting  or  obtaining  the  images  of  buried  objects.  It  also  proposed  to 
 require  GPRs  to  include  a  switch  or  other  mechanism  to  ensure  that  operation  occurs  only  when  the  device  is  activated  by  an  operator  and  is  aimed  directly  down  at  the  ground. 

 37.  In  the  Notice,  the  Commission  also  indicated  it  is  unclear  whether  the  same  considerations  apply  to  other  imaging  devices  used  to  detect  or  obtain  the  images  of  objects  inside  or 
 behind  walls  or  other  surfaces.  82  For  example,  in  contrast  to  GPRs  where  signals  are  aimed  at  the  ground,  wall  imaging  and  through-  wall  imaging  devices  could  aim  their  energy  in  any  direction.  While 
 the  wall  structure  could  attenuate  these  signals,  the  amount  of  attenuation  can  vary  widely  depending  on  the  composition  of  the  wall.  The  Commission  noted,  however,  that  it  expected  that  such  systems  would 
 have  a  low  proliferation  and  would  be  operated  infrequently.  Thus,  the  Commission  indicated  that  one  option  would  be  to  treat  all  imaging  devices  the  same  way  as  GPRs.  Alternatively,  it  indicated  that  it 
 could  restrict  the  operation  of  such  devices  to  bands  below  a  certain  frequency  or  apply  other  restrictions  to  such  devices.  Comments  were  invited  on:  1)  these  and  other  approaches  for  GPRs  and  imaging 
 systems;  2)  the  provisions  needed  to  ensure  that  these  systems  operate  only  when  they  are  in  contact  with  a  wall;  3)  whether  the  operation  of  through-  wall  imaging  systems  should  be  limited  to  parties  eligible  for 
 licensing  under  the  Public  Safety  Pool  of  frequencies  in  Part  90  of  our  rules,  as  required  under  the  earlier  waiver  to  Time  Domain;  83  and,  4)  whether  through-  wall  imaging  systems  should  be  required  to 
 incorporate  automatic  power  control  features  that  would  reduce  power  levels  to  the  minimum  necessary  to 

 81  Our  concerns  apply  to  all  emissions  within  the  10  dB  bandwidth  of  the  UWB  signal,  not  just  at  the  center 
 frequency.  82 
 Time  Domains  through-  wall  imaging  system,  authorized  under  a  waiver  issued  on  June  29,  1999,  by  the  Chief,  Office  of  Engineering  and  Technology,  operates  over  a  frequency  band  ranging  from  a  few  hundred  Hertz  to 

 greater  than  4  GHz.  Through-  wall  imaging  systems  are  limited  to  products  that  detect  objects  located  on  the  other  side  of  a  wall.  Under  the  waiver,  operation  was  limited  to  parties  eligible  for  licensing  under  the  Public  Safety  Pool 
 of  frequencies  in  Part  90  of  this  chapter.  83 
 Waivers  were  issued  on  June  29,  1999,  to  Time  Domain  Corporation,  Zircon,  and  U.  S.  Radar  and  on  August  6,  2001,  to  Kohler  Co.  to  permit  the  limited  marketing  of  UWB  devices. 
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 function  based  on  the  composition  of  the  surface  and  its  absorption  of  RF  energy. 
 38.  The  Commission  observed  that  it  appears  that  most  other  applications  of  UWB  technology  could  satisfactorily  operate  in  a  variety  of  regions  of  the  spectrum.  It  further  observed  that 

 UWB  devices  generally  can  operate  compatibly  with  other  radio  services  in  the  region  of  the  spectrum  above  approximately  2  GHz  without  causing  harmful  interference  to  other  radio  services  for  two  main 
 reasons:  1)  the  UWB  signals  will  quickly  fall  off  to  levels  below  the  background  noise  because  of  the  high  propagation  losses  at  2  GHz  and  above;  and  2)  most  radio  services  operating  above  2  GHz  use 
 directional  antennas  that  generally  discriminate  against  reception  of  undesired  signals.  Accordingly,  the  Commission  proposed  to  allow  the  operation  of  all  types  of  UWB  devices  on  frequencies  above 
 approximately  2  GHz,  subject  to  the  general  limits  on  technical  operation  set  forth  elsewhere  herein. 
 39.  The  Commission  also  requested  comment  on  alternative  approaches  to  restricting  or  prohibiting  operations  in  the  frequency  bands  below  2  GHz.  It  noted  that  certain  UWB  applications 

 might  be  feasible  using  extremely  low  signal  levels.  Comments  were  invited  as  to  whether  and  at  what  levels,  if  any,  operation  should  be  permitted  in  the  restricted  bands  below  2  GHz  for  devices  that  can 
 operate  using  extremely  low  signal  levels.  While  UWB  technology  generally  cannot  completely  notch  out  certain  frequency  bands,  comments  were  requested  as  to  the  viability  of  establishing  a  general  emission 
 limit  for  UWB  devices  below  2  GHz,  and  whether  a  more  stringent  limit,  or  notch,  should  be  applied  to  the  GPS  band. 

 40.  Discussion.  As  discussed  above,  we  are  establishing  different  technical  standards  and  operating  restrictions  for  three  categories  of  UWB  devices  based  on  their  potential  to  cause  interference. 
 These  three  categories  of  UWB  devices  are  1)  imaging  systems  including  ground  penetrating  radar  (GPR),  wall,  through-  wall,  surveillance,  and  medical  imaging  devices,  2)  vehicular  radar  systems,  and  3) 
 communications  and  measurement  systems.  The  discussion  below  sets  forth  the  frequency  and  operational  limitations  that  will  apply  to  each  of  these  device  categories. 

 1.  Imaging  Systems 
 41.  Most  of  the  commenting  parties  support  allowing  GPRs  to  operate  in  all  frequency  bands  provided  that  certain  conditions  are  met,  such  as  requiring  a  switch  to  avoid  unattended  operation  and 

 ensuring  that  they  are  operated  in  close  proximity  to  the  ground.  The  commenting  parties  expressed  differing  views,  however,  with  regard  to  other  types  of  imaging  systems.  Some  parties  state  that  imaging 
 systems  need  to  operate  across  a  broad  range  of  frequencies  in  order  to  accommodate  the  wide  range  of  applications  and  to  allow  imaging  sensors  to  effectively  penetrate  a  wide  variety  of  materials.  Other 
 commenting  parties  are  concerned  that  imaging  systems  may  be  more  likely  to  cause  interference  to  licensed  services.  These  parties  suggest  limiting  imaging  systems  to  certain  frequency  bands  and 
 applying  other  restrictions  on  their  use. 
 42.  The  ARRL,  for  example,  states  that  it  does  not  object  to  permitting  GPRs  to  operate  anywhere  in  the  spectrum,  subject  to  appropriate  emission  limits.  84  It  states  that  these  devices  are 

 expected  to  be  deployed  in  limited  numbers  and  will  direct  their  signals  towards  the  ground.  ARINC,  ARRL,  and  ATA  state  that  limiting  UWB  operations  in  restricted  bands  to  GPRs  that  direct  most  of  their 
 energy  into  the  ground  may  serve  to  minimize  the  impact  of  any  harmful  interference  to  GPS  and  other  safety-  of-  life  operations.  85  Nortel  states  that  GPRs  are  unlikely  to  cause  significant  interference  to 
 communications  systems  as  the  energy  is  directed  into  the  ground  and  extraneous  radiation  is  low.  86 

 84  ARRL  comments  at  pg.  16. 
 85  ARINC  &  ATA  comments  at  pg.  13. 
 86  Nortel  comments  at  pg.  7. 
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 Nortel  also  agreed  that  a  switch  or  other  mechanism  should  be  required  to  ensure  operation  only  when  activated  by  the  operator  and  aimed  at  the  ground.  The  USGPSIC  also  requested  that  GPRs  be  equipped 
 with  a  switch  to  shut  off  the  transmitter  if  it  was  not  in  contact  with  the  ground.  87  Sirius  requested  that  GPRs  operate  exclusively  below  2  GHz  so  as  to  avoid  the  DARS  frequency  band.  88  Aether  Wire 
 indicated  that  the  use  of  frequencies  below  1  GHz  is  optimal  for  transmitting  through  walls,  pavement,  debris,  earth,  water,  snow,  etc.  89  The  Colorado  School  of  Mines  stated  that,  depending  on  soil  conditions, 
 GPR  operation  may  be  in  the  100  MHz  to  2  GHz  region.  90  On  the  other  hand,  USGPSIC  stated  that  there  is  no  valid  reason  why  GPRs  can  not  operate  above  3  GHz.  91 

 43.  AOPA  questioned  permitting  GPRs  to  operate  one  meter  from  the  ground.  It  argued  that  one  meter  represents  a  half-  wavelength  of  about  150  MHz  and  indicates  that  GPRs  can  emit  significant 
 energy  above  this  frequency  and  states  that  there  is  the  possibility  of  substantial  coupling  leakage  and  reflection  from  the  grounds  surface.  92  Alloy  requested  that  GPRs  be  limited  to  a  maximum  one-  foot 
 separation  from  the  ground,  requiring  the  GPR  to  be  as  close  to  the  ground  as  possible,  since  metal  objects  could  reflect  the  RF  signal.  93  Peter  Annan  objected  to  requiring  an  automatic  switch  permitting 
 operation  only  when  the  GPR  is  pointed  at  the  ground,  indicating  that  GPRs  may  be  operated  on  steep  slopes,  into  the  sides  of  cliffs,  or  retaining  walls,  in  underground  pipes,  and  at  other  locations.  94  Mr. 
 Annan  requested  that  GPRs  be  permitted  to  have  an  override  switch,  e.  g.,  a  press  to  operate  switch.  He  also  requested  that  certification  of  GPRs  not  be  required  since  the  interference  potential  from  GPRs  is 
 low. 
 44.  With  regard  to  imaging  systems,  Bosch  argued  that  the  emission  limits  for  UWB  should  ensure  that  there  is  no  interference  to  other  services  and  that  the  use  of  wall  contact  switches  as  well  as 

 automatic  power  control  are  unnecessary.  95  It  pointed  out  that  automatic  power  control  is  impracticable  because  it  is  not  possible  to  predict  the  exact  attenuation  of  every  wall.  TDC  indicated  that  the  best  center 
 frequency  for  through-  wall  sensors  is  2  GHz  due  to  the  ability  at  this  frequency  to  penetrate  construction  materials.  96  TDC  also  expressed  concern  regarding  the  requirement  for  a  wall  contact  switch,  noting  that 
 there  may  not  always  be  flat  surfaces,  e.  g.,  walls  in  a  collapsed  building.  97  TDC  also  noted  that  police  would  prefer  the  ability  to  operate  these  devices  remotely  for  the  safety  of  their  personnel.  Zircon  stated 
 that  its  UWB  radar  operates  between  200  MHz  and  4  GHz,  adding  that  the  use  of  frequencies  below  2  GHz  is  necessary  to  obtain  through-  wall  imaging  definition  of  narrow  objects.  98  While  Zircon  stated  that 
 it  does  not  oppose  a  contact  switch  in  principle  it  needs  an  override  mechanism  to  permit  a  few  seconds  of 

 87  USGPSIC  comments  at  pg.  23-  24. 
 88  Sirius  comments  at  pg.  15. 
 89  Aether  Wire  comments  at  pg.  6. 
 90  Colorado  School  of  Mines  reply  comments  at  pg.  3-  4. 
 91  USGPSIC  reply  comments  at  pg.  10. 
 92  AOPA  comments  at  pg.  7.  NBAA  comments  at  pg.  8.  Sirius  comments  at  pg.  19-  20. 
 93  Alloy  reply  comments  at  pg.  14. 
 94  A.  Peter  Annan  comments  at  pg.  3.  The  Colorado  School  of  Mines  on  page  4  of  its  reply  comments  also 
 noted  that  GPRs  are  sometimes  used  to  investigate  cliff  faces  and  overhangs.  95 
 Bosch  comments  at  pg.  3  and  reply  comments  at  pg.  2.  96 
 TDC  comments  at  pg.  11.  97 
 TDC  comments  at  pg.  26.  98 
 Zircon  comments  at  pg.  1  and  5. 
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 calibration  or  to  pass  closely  over  uneven  surfaces  that  might  not  always  permit  direct  contact.  99  XM  stated  that  it  is  unlikely  that  imaging  systems  would  pose  a  significant  threat  of  interference  to  DARS.  100 
 45.  Nortel  noted  that  caution  is  needed  with  systems  that  are  designed  to  penetrate  walls  or  floors  as  emissions  from  these  systems  could  interfere  with  in-  building  communications  systems.  101  Alloy 
 expressed  concern  that  through-  wall-  imaging  systems  could  be  aimed  at  CMRS  antennas  and  wants  these  devices  activated  only  if  they  are  in  direct  contact  with  a  wall  surface  and  equipped  with  automatic  power 
 control.  102  USGPSIC  requested  that  the  use  of  through-  wall  imaging  systems  be  restricted  to  public  safety  applications  or  to  the  protection  of  life  or  property  in  order  to  avoid  proliferation  of  the 
 equipment.  103  It  also  stated  that  these  devices  must  be  required  to  meet  all  of  the  conditions  established  by  NTIA  for  UWB  devices  operating  under  a  waiver  from  the  Commission.  104  These  conditions  mandate 
 the  keeping  of  records  of  all  parties  to  whom  the  equipment  is  marketed,  coordination  by  the  equipment  users  of  detailed  areas  of  operation  with  the  Frequency  Assignment  Subcommittee  of  the 
 Interdepartmental  Radio  Advisory  Committee  under  NTIA,  and  other  requirements.  TDC  stated  that  the  operation  of  through-  wall  systems  should  not  be  limited  to  law  enforcement  and  public  safety  even  though 
 the  more  sophisticated  versions  were  likely  to  be  used  by  these  groups.  105  TDC  noted  that  similar  technology  could  provide  high  security  sensors  for  commercial  and  residential  applications.  Zircon  also 
 requested  that  the  Commission  not  restrict  the  operation  of  imaging  systems  to  safety-  of-  life  or  property  as  its  customers  would  be  contractors  and  remodelers  who  would  not  be  permitted  to  use  the  equipment  under 
 these  conditions.  106 
 46.  Discussion.  Based  on  the  record  and  recommendations  from  NTIA,  107  we  find  that  imaging  systems  can  be  permitted  to  operate  in  most  regions  of  the  frequency  spectrum  without  causing  harmful 

 interference  provided  appropriate  technical  standards  and  operational  restrictions  are  applied  to  their  use.  With  regard  to  GPRs,  we  find  that  these  devices  must  operate  over  a  range  of  frequencies,  including  in  the 
 region  below  2  GHz,  in  order  to  obtain  the  penetration  depth  and  resolution  necessary  to  detect  and  obtain  the  images  of  buried  objects.  We  also  agree  with  the  majority  of  the  commenting  parties  that  the  risk  of 
 interference  from  GPRs  is  low  since  the  energy  from  these  devices  is  directed  into  the  ground,  where  most  of  the  energy  is  absorbed,  and  emissions  in  other  directions  can  be  shielded  without  affecting  the 
 operating  characteristics  of  the  GPR.  Further,  we  expect  that  GPRs  will  have  a  low  proliferation  and  usually  operate  at  infrequent  intervals.  In  addition,  the  low  heights  at  which  GPRs  are  operated  and  the 
 low  duty  cycles  employed  by  GPRs  108  ensure  that  there  is  a  minimal  risk  of  interference  from  these  devices. 

 47.  GPRs  must  operate  only  when  directed  at  the  ground  and  in  contact  with,  or  in  close  proximity  (e.  g.,  1  meter)  to,  the  ground  for  the  purpose  of  detecting  or  obtaining  the  images  of  buried 

 99  Zircon  reply  comments  at  pg.  3. 
 100  XM  reply  comments  at  pg.  6,  footnote  8. 
 101  Nortel  comments  at  pg.  7. 
 102  Alloy  reply  comments  at  pg.  14-  16. 
 103  USGPSIC  comments  at  pg.  23-  34. 
 104  See  letter  of  June  15,  1999,  from  William  T.  Hatch  of  NTIA  to  Dr.  Dale  Hatfield,  Chief,  OET,  FCC. 
 105  TDC  comments  at  pg.  26. 
 106  Zircon  reply  comments  at  pg.  3. 
 107  See  letter  of  February  13,  2002,  from  William  Hatch,  supra. 
 108  GPRs  generally  operate  at  low  PRFs  as  they  must  pause  between  pulses  to  give  the  signal  transmitted  into 
 the  ground  sufficient  time  to  be  reflected  and  to  return  to  the  receiver. 
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 objects,  and  we  will  require  that  they  be  tested  at  their  operational  height.  This  will  ensure  that  any  emissions  due  to  leakage  or  to  reflections  can  be  detected.  We  do  not  agree  with  Alloy  that  reflections 
 that  may  occur  from  infrequent  metal  objects  that  may  appear  under  the  GPR  would  increase  the  potential  for  interference.  Such  objects  would  likely  be  quite  small  and  would  reflect  the  signal  low  to  the  ground 
 where  it  would  quickly  be  attenuated  with  distance  and  by  intervening  objects.  To  ensure  that  operation  occurs  only  when  the  GPR  is  directed  towards  the  ground,  we  are  requiring  that  the  device  be  equipped 
 with  a  switch  accessible  by  the  operator.  The  switch  shall  be  manually  operated  and  shall  cause  the  transmitter  to  cease  operation  within  10  seconds  of  being  released  by  the  operator.  It  is  permissible  for  the 
 switch  to  be  operated  by  remote  control  provided  the  GPR  system  ceases  transmission  within  10  seconds  of  the  remote  switch  being  released  by  the  operator. 

 48.  We  reject  the  request  to  exempt  GPRs  from  the  Commissions  equipment  certification  procedure.  This  procedure  was  established  as  a  method  to  ensure  that  RF  products  comply  with  the 
 appropriate  standards  before  they  are  imported,  marketed  or  used.  We  do  not  have  sufficient  experience  with  this  equipment  at  this  time  to  ensure  that  such  devices  do,  or  will  continue  to,  meet  our  technical 
 standards. 
 49.  We  recognize  that  wall,  through-  wall,  and  medical  imaging  systems  generally  do  not  direct  their  energy  into  the  ground  and  therefore  present  a  somewhat  greater  risk  of  interference. 

 However,  it  is  desirable  for  these  imaging  systems  to  operate  across  a  broad  range  of  frequencies  in  order  to  accommodate  different  applications  and  to  effectively  penetrate  a  wide  variety  of  materials.  We 
 believe  that  sufficient  protection  from  harmful  interference  can  be  achieved  by  a  combination  of  technical  requirements  and  operational  restrictions  on  imaging  systems.  We  are  therefore  designating  three  classes 
 of  imaging  systems,  each  subject  to  different  technical  standards  and  operational  restrictions. 
 50.  Low-  frequency  imaging  systems.  The  first  class  of  imaging  systems  includes  all  imaging  systems  operating  with  a  10  dB  bandwidth  that  is  wholly  contained  below  960  MHz.  These  systems  will 

 be  permitted  to  operate  at  the  emission  limits  contained  in  15.209.  They  are  also  required  to  meet  the  following  out-  of-  band  emission  limits: 

 Frequency  in  MHz  EIRP  in  dBm  960-  1610 
 1610-  1990  Above  1990  -65.3  -53.3  -51.3 

 51.  We  are  restricting  the  use  of  this  class  of  equipment  to  parties  eligible  for  licensing  under  the  provisions  of  Part  90  of  the  FCCs  rules.  We  also  are  requiring  that  the  operators  of  imaging  systems 
 in  this  class  complete  a  coordination  procedure  with  the  Government.  These  devices  radiate  energy  in  arbitrary  directions  and  operate  in  the  vicinity  of  materials  that  may  provide,  in  some  instances,  very  little 
 energy  absorption.  While  the  record  showed  that  the  GPS  and  other  authorized  services  are  generally  robust  against  interference  from  devices,  such  as  GPRs,  with  low  PRFs,  the  record  did  not  directly 
 support  extending  this  conclusion  to  all  systems  operating  in  this  low  frequency  range.  Other  technical  and  operational  requirements  for  low-  frequency  imaging  systems  are  contained  in  new  Section  15.509  in 
 Appendix  D.  The  specifics  of  the  coordination  process  are  detailed  in  the  Section  15.525  contained  in  Appendix  D  of  this  Order. 

 52.  High-  frequency  Imaging  Systems.  The  second  class  of  imaging  systems  are  those  that  operate  with  a  -10  dB  bandwidth  between  3.10  GHz  and  10.6  GHz.  109  Emission  levels  from  this  category 
 109  It  should  be  noted  that  GPRs  are  a  specialized  application  of  imaging  systems  and  can  operate  under  this 
 second  category  of  imaging  systems  using  any  PRF  provided,  however,  that  they  comply  with  all  of  the  other  technical  and  operational  restrictions  associated  with  this  equipment  category. 
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 of  device  must  meet  an  emissions  mask  for  the  appropriate  frequency  bands.  The  emission  limits  are  as  follows: 
 Frequency  in  MHz  EIRP  in  dBm  Below  960 
 960-  1610  1610-  1990 
 1990-  3100  3100-  10600 
 Above  10600 

 15.209  limits  -65.3 
 -53.3  -51.3 
 -41.3  -51.3 

 53.  The  high-  frequency  imaging  system  class  includes  GPRs,  wall,  and  medical  imaging  devices.  As  with  the  low-  frequency  imaging  systems,  Government  coordination  is  required  for  the 
 operation  of  these  devices,  following  the  procedures  described  in  Section  15.525  in  Appendix  D.  Specific  technical  and  operational  requirements  for  high-  frequency  UWB  devices  are  contained  in  Section  15.513 
 in  Appendix  D. 
 54.  Mid-  frequency  Imaging  Systems.  This  class  of  imaging  systems  consists  solely  of  through-  wall  and  surveillance  systems.  These  devices  operate  with  a    10  dB  bandwidth  between  1990 

 MHz  and  10,  600  MHz.  Higher  unwanted  emission  limits  than  those  applied  to  the  other  classes  of  imaging  devices  are  permitted.  The  emission  limits  are  as  follows: 

 Frequency  in  MHz  EIRP  in  dBm  Below  960 
 960-  1610  1610-  1990 
 1990-  10600  Above  10600 

 15.209  limits  -53.3 
 -51.3  -41.3 
 -51.3 
 55.  Parties  seeking  to  operate  this  mid-  frequency  class  of  devices  must  be  eligible  for  licensing  under  the  provisions  of  Part  90  of  the  FCCs  rules.  The  systems  in  this  class  are  considered  to 
 pose  a  greater  risk  for  harmful  interference  because  of  the  lower  frequency  of  the  fundamental  emission  and  the  higher  power  levels  reflected  in  the  less  conservative  emissions  mask;  however,  consideration  of 
 the  substantial  benefits  to  the  public  safety  and  the  limited  user  base  tend  to  mitigate  the  interference  concerns.  This  class  of  UWB  imaging  systems  requires  Government  coordination.  This  coordination  will 
 provide  for  operation  in  a  pre-  approved  geographic  area,  with  perhaps,  certain  restrictions  on  specific  locations  identified  by  the  Government.  This  should  provide  maximum  flexibility  to  safety  services  while 
 still  assuring  that  the  risk  for  harmful  interference  is  appropriately  minimized.  Surveillance  systems  will  operate  only  at  fixed  locations  such  that  harmful  interference  can  be  avoided  through  coordination.  In 
 addition,  if  harmful  interference  were  to  occur  the  source  can  be  readily  identified  and  corrected.  See  Section  15.511  for  the  specific  technical  provisions  for  mid-  frequency  UWB  devices. 

 56.  The  limits  specified  above  for  imaging  systems  reflect  an  abundance  of  caution  to  protect  the  GPS  and  PCS  services,  and  the  passive  bands  employed  in  radio  astronomy  and  by  satellite  sensors. 
 We  believe  that  by  restricting  the  parties  and  requiring  coordination  before  the  device  is  used  that  the  proliferation  of  these  systems  will  be  limited  and  the  use  controlled  to  a  narrow  range  of  applications  that 
 should  not  present  interference  concerns.  We  believe  that  the  requirement  for  coordination  will  have  a  minimal  impact  on  UWB  equipment  users  as  NTIA  must  complete  its  coordination  efforts  within  15 
 business  days  of  its  receipt  of  the  request  for  routine  UWB  operations.  Special  temporary  operations  may  be  handled  with  a  much  faster  turn-  around  time  when  circumstances  warrant.  Further,  the  operation  of 
 UWB  systems  in  emergency  situations  can  be  commenced  immediately  pursuant  to  the  notification  procedures  specified  in  47  C.  F.  R.  Section  2.405(  a)-(  e).  We  believe  that  these  technical  requirements  and 
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 operational  restrictions  will  ensure  that  imaging  systems  do  not  cause  harmful  interference. 
 57.  We  agree  with  Bosch,  TDC  and  Zircon  that  there  is  no  need  for  a  wall  contact  switch  or  automatic  power  control  for  imaging  devices.  However,  as  with  GPRs,  we  are  requiring  that  wall 

 imaging  systems  be  equipped  with  a  manually  operated  switch,  the  release  of  which  causes  the  transmitter  to  cease  operation  within  no  more  than  10  seconds.  Recognizing  that  police  and  other  public  safety 
 officials  may  employ  these  systems  in  hostile  situations,  we  will  permit  this  switch  to  operate  by  remote  control.  We  do  not  agree  with  the  request  from  USGPSIC  to  require  detailed  record  keeping  such  as  that 
 which  was  required  by  NTIA  for  the  UWB  manufacturers  that  obtained  waivers  from  the  Commission. 
 2.  Other  UWB  Devices 
 58.  Comments.  The  comments  from  parties  associated  with  an  authorized  radio  service  generally  objected  to  the  operation  of  UWB  devices  in  their  spectrum  regardless  of  the  emission  level. 

 For  example,  objections  to  the  operation  of  UWB  were  filed  by  ARRL  regarding  the  amateur  bands,  Cisco  regarding  MMDS  operations,  Motorola  and  Sprint  PCS  regarding  operation  in  the  PCS  band,  Sprint 
 on  several  services  including  MDS,  ITFS,  PCS  and  LMDS,  XM  and  Sirius  regarding  operation  in  the  SDARS  band,  Nortel  regarding  PCS,  UNII  110  and  fixed  wireless  access  systems,  AT&  T  on  UNII 
 operation,  MCHI  regarding  MSS,  and  several  others.  111  Based  on  these  objections,  several  different  frequencies  were  suggested  in  the  comments  below  which  UWB  devices  should  not  be  permitted  to 
 operate.  For  example,  Nortel  requested  that  UWB  systems  not  be  permitted  to  operate  below  5.9  GHz.  112  Sirius  requested  that  UWB  systems  not  be  permitted  to  operate  below  2.9  GHz,  with  a  possible  exception 
 for  GPRs  and  wall  imaging  systems.  113  Lockheed  Martin  requested  that  UWB  systems  be  excluded  from  operating  below  2.9  GHz  due  to  the  sensitive  nature  of  many  operations  conducted  in  restricted  bands 
 used  for  military  and  public  safety  applications  and  other  sensitive  uses.  114  MCHI  requested  that  UWB  devices,  other  than  certain  ground  radars,  not  be  permitted  below  3  GHz.  115  Rockwell  requested  that 
 UWB  devices  be  prohibited  from  operating  below  5.15  GHz,  except  for  GPRs  and  wall  imaging  systems,  in  order  to  accommodate  radio  altimeters  at  4.2-  4.4  GHz  and  MLS  receivers  at  5.  03-  5.09  GHz.  116  ARRL 
 requested  that  non-  GPRs  be  located  above  2.5  GHz.  117  XM  requested  that  UWB  devices  be  prohibited  from  operating  below  3  GHz  in  order  to  provide  protection  to  DARS.  118  Alloy  wants  all  UWB  devices, 
 except  GPRs,  to  operate  above  2.7  GHz.  119  ARINC  &  ATA  want  UWB  operation  permitted  only  above  5.5  GHz  and  then  only  outside  of  the  existing  restricted  bands.  120  ATA  and  several  other  industry 

 110  UNII  devices  operate  under  Part  15  of  our  rules  and  are  not  provided  any  protection  from  harmful 
 interference.  See  47  C.  F.  R.    15.5.  111 
 ARRL  comments  at  pg.  2-  3.  Cisco  comments  at  pg.  3.  Motorola  comments  at  pg.  11-  30.  Sprint  PCS  reply  comments  at  pg.  2.  Sprint  comments  at  pg.  3.  XM  comments  at  pg.  10.  Sirius  comments  at  pg.  7-  10.  Nortel 

 comments  at  pg.  6.  AT&  T  comments  at  pg.  5.  MCHI  comments  at  pg.  1-  2.  We  note  that  UNII  is  a  Part  15  operation  and  is  provided  no  protection  from  harmful  interference.  See  47  C.  F.  R.    15.  5. 
 112  Nortel  comments  at  pg.  6. 
 113  Sirius  comments  at  pg.  ii  and  7-  10. 
 114  Lockheed  Martin  comments  at  pg.  8. 
 115  MCHI  comments  at  pg.  4. 
 116  Rockwell  comments  at  pg.  5. 
 117  ARRL  comments  at  pg.  17. 
 118  XM  comments  at  pg.  1  and  10. 
 119  Alloy  reply  comments  at  pg.  16. 
 120  ARINC  &  ATA  reply  comments  at  pg.  7. 
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 representatives  stated  later  that  UWB  operation  must  be  above  6  GHz.  121  American  Trans  Air  stated  that  UWB  devices  should  not  be  permitted  to  operate  in  any  of  the  safety-  of-  life  bands.  122  M/  A-  Com  noted 
 that  the  bands  within  which  Motorola,  Sprint,  Nortel,  Cisco  and  others  requested  that  UWB  systems  be  prohibited  from  operating  are  not  restricted  bands  and  may  already  be  used  by  Part  15  devices.  123 

 59.  TDC  stated  that  the  best  center  frequencies  are  as  follows:  2  GHz  for  wireless  local  area  networks  with  precision  tracking,  precision  tracking  systems,  buried  victim  rescue  radar,  and  security 
 fences;  4  GHz  for  RF  identification  tags,  medical  telemetry  tags,  short  range  high  resolution  radar,  and  short  range  data  links;  and  8  GHz  for  automotive  pre-  crash  sensors,  airbag  deployment  sensors, 
 construction  inspection  equipment,  and  high  resolution  radars.  124  Fantasma  indicated  that  it  could  operate  above  2  GHz.  125  MSSI  stated  that  UWB  should  initially  be  allowed  above  3.1  GHz.  126  XSI  indicated  that 
 its  UWB  equipment  could  operate  with  a  center  frequency  above  3.1  GHz.  Valeo  Electronics  stated  that  it  expects  automotive  radars  to  be  designed  at  frequencies  above  4  GHz  as  antenna  aperture  is  proportional 
 to  wavelength  and  space  is  limited.  127  Daimler  Chrysler  wants  to  operate  its  vehicular  radar  systems  with  a  center  frequency  at  24.125  GHz.  128 

 60.  XM  noted  that  radio  receivers  for  several  services  operating  above  2  GHz  do  not  rely  on  directional  antennas,  but  added  that  most  radio  receivers  operating  above  3  GHz  do  rely  on  directional 
 antennas.  129  MSSI  noted  that  fifty  percent  of  the  U.  S.  Government  radio  operations  and  forty  percent  of  non-  government  radio  operations  occur  below  3.1  GHz  and  requested  that  UWB  operation  be  permitted 
 above  this  frequency.  130  NTIA,  in  its  analysis  of  potential  interference  from  UWB  systems  to  non-  GPS  systems,  concluded  that  the  operation  of  UWB  devices  is  feasible  in  portions  of  the  spectrum  between 
 about  3.1  and  5.65  GHz  at  heights  of  about  2  meters  with  some  operating  constraints  but  that  operation  below  3.1  GHz  would  be  quite  challenging.  131  This  statement  by  NTIA  was  echoed  in  several  of  the 
 comments  filed  in  response  to  the  NTIA  analysis. 
 61.  Aether  Wire  stated  that  rather  than  confining  operation  to  above  2  GHz  we  should  set  reasonable  limits  in  the  GPS  bands  consistent  with  noise  sources  that  already  exist  and  let  manufacturers 

 choose  how  to  meet  these  limits.  132  It  added  that  an  outright  ban  to  UWB  operation  below  2  GHz  would  be  dictating  a  political  solution  to  an  engineering  problem  and  would  favor  some  UWB  systems  over 
 others.  The  USGPSIC  requested  that  we  require  UWB  transmitters  to  be  equipped  with  filters  to  protect  the  GPS  band,  stating  that  it  is  impossible  to  prevent  significant  changes  in  the  frequency  and  bandwidth 

 121  ATA  et  al  ex  parte  comments  of  6/  6/  01,  5/  18/  01. 
 122  American  Trans  Air  reply  comments  at  pg.  2. 
 123  M/  A-  Com  reply  comments  at  pg.  2. 
 124  TDC  comments  at  pg.  11. 
 125  Fantasma  comments  at  pg.  3. 
 126  MSSI  comments  at  pg.  2. 
 127  Valeo  Electronics  comments  at  pg.  7. 
 128  Daimler  Chrysler  ex  parte  filing  of  7/  31/  01. 
 129  XM  comments  at  pg.  10. 
 130  MSSI  comments  at  pg.  10  and  reply  comments  at  pg.  2. 
 131  NTIA  Special  Publication  01-  43,  supra,  at  pg.  x.  We  note  that  NTIA,  in  performing  its  analysis  leading  up 
 to  this  statement,  did  not  consider  the  12  dB  reduction  below  the  Part  15  general  emission  limits  that  was  proposed  in  the  Notice. 

 132  Aether  Wire  comments  at  pg.  7. 
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 of  a  UWB  emitter  due  to  accidental  or  intentional  changes  to  the  UWB  antenna.  133  It  attached  a  new  element  to  a  UWB  antenna  and  removed  a  radiating  element  from  another  UWB  device  to  demonstrate 
 that  the  UWB  transmitter  could  be  made  to  change  frequency. 
 62.  Discussion.  We  recognize  that  the  UWB  proponents  wish  to  build  various  types  of  UWB  devices  oriented  towards  the  general  consumer  marketplace.  However,  we  also  are  concerned  about 

 harmful  interference  absent  sufficient  constraints.  As  noted  earlier,  we  believe  that  a  cautious  approach  is  needed  during  the  initial  stages  of  UWB  development.  For  that  reason,  we  are  adopting  very  conservative 
 emission  limits  for  consumer  UWB  applications  for  three  categories  of  devices:  vehicular  radar  systems;  indoor;  and  hand-  held,  short  range,  peer-  to-  peer  systems. 

 63.  Vehicular  Radar  Systems.  We  are  limiting  vehicular  radar  systems  to  operation  with  a  center  frequency  greater  than  24.075  GHz.  134  Further,  we  are  requiring  that  the  frequency  at  which  the 
 highest  radiated  emission  level  occurs  also  must  be  greater  than  24.075  GHz  and  that  the  -10  dB  bandwidth  be  contained  between  22-  29  GHz.  This  is  high  enough  in  frequency  to  ensure  antenna 
 directionality  along  with  a  high  level  of  signal  attenuation  with  increasing  distance  and  intervening  objects.  It  also  is  high  enough  in  frequency  to  permit  the  use  of  an  antenna  small  enough  to  be  mounted 
 on  an  automobile.  Further,  by  requiring  the  center  frequency  to  be  this  high  the  emissions  appearing  within  the  frequency  bands  below  10.  6  GHz  that  were  investigated  by  NTIA  and  others  should  be  similar 
 to  spurious  emissions  from  conventional  Part  15  transmitters  or  to  emissions  from  digital  devices  and  of  no  greater  interference  threat.  Consistent  with  our  cautious  approach,  we  are  requiring  that  emissions 
 below  960  MHz  be  at  or  below  the    15.  209  limits  and  that  emissions  appearing  above  960  MHz  conform  to  the  following  emissions  mask: 

 Frequency  in  MHz  EIRP  in  dBm  960-  1610 
 1610-  22,000  22,000-  29,  000 
 29,000-  31,  000  Above  31,000 

 -75.3  -61.3 
 -41.3  -51.3 
 -61.3 

 64.  While  we  believe  that  the  emission  mask  that  we  are  adopting  will  prevent  harmful  interference  to  radio  systems  operating  in  these  bands,  out  of  an  abundance  of  caution  we  also  are 
 requiring  that  vehicular  radar  systems  employ  directional  antennas  or  other  methods  that  will  attenuate  the  emissions  38  degrees  or  higher  above  the  horizontal  plane  in  the  23.6-  24.0  GHz  band  by  at  least  25  dB 
 below  the  Part  15  general  emission  limits.  135  As  requested  by  NTIA,  and  as  discussed  in  paragraphs  195-  197  of  this  Order,  this  level  of  attenuation  will  be  increased  in  steps  such  that  emissions  30  degrees  or 
 higher  above  the  horizontal  plane  in  the  23.6-  24.  0  GHz  band  must  be  attenuated  35  dB  below  the  Part  15  general  emission  limits  by  January  1,  2014.  Since  we  expect  vehicular  radar  to  become  as  essential  to 
 passenger  safety  as  air  bags  for  motor  vehicles,  the  greater  number  of  vehicles  using  these  systems  could  pose  an  increased  risk  to  terrestrial  passive  sensing  by  satellites.  Therefore,  we  are  adopting  the 
 additional  emission  requirements.  See  Section  15.515  in  Appendix  D  for  the  specific  provisions  for 
 133  USGPSIC  comments  of  7/  25/  01.  XSI  in  its  comments  of  7/  25/  01  at  pg.  4  and  9  noted  that  its  antenna  can  not 
 be  manipulated  in  such  a  manner.  The  Commission  also  previously  recognized  that  UWB  devices  might  not  be  able  to  notch  out  frequency  bands  that  are  a  subset  of  their  operating  frequencies.  See  Notice,  supra,  at  para.  23  and  30. 

 134  Most  comments  supporting  UWB  operation  for  vehicles  wished  to  operate  above  24  GHz. 
 135  The  angle  above  the  horizontal  plane  is  based  on  measurements  from  a  properly  installed  vehicle  radar 
 system  with  the  vehicle  resting  horizontally. 
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 vehicular  radars. 
 65.  Indoor  UWB  Systems.  Devices  operating  under  this  category  must  demonstrate  that  the  system  units  will  fail  to  operate  if  they  are  removed  from  the  indoor  environment.  One  acceptable 

 procedure  may  be  to  show  that  the  transmitting  unit  requires  AC  power  to  function.  Based  on  the  concerns  expressed  by  NTIA  and  others  regarding  operation  below  3.1  GHz,  we  are  requiring  that  10  dB 
 bandwidth  of  indoor  UWB  systems  must  lie  between  3.1  GHz  and  10.6  GHz.  We  are  adopting  a  very  conservative  out  of  band  emission  mask  to  address  the  concerns  of  companies  which  make  or  market 
 indoor  electronic  equipment.  In  the  frequency  band  below  960  MHz  these  devices  are  permitted  to  emit  at  or  below  the    15.209  limits,  and  emissions  appearing  above  960  MHz  will  conform  to  the  following 
 emissions  mask: 
 Frequency  in  MHz  EIRP  in  dBm  960-  1610 

 1610-  1990  1990-  3100 
 3100-  10600  Above  10600 

 -75.3  -53.3 
 -51.3  -41.3 
 -51.3 

 66.  An  additional  requirement  for  indoor  UWB  devices  is  that  they  may  transmit  only  when  operating  with  a  receiver.  A  device  connected  to  AC  power  is  not  constrained  to  reduce  or  conserve 
 power  by  ceasing  transmission,  so  this  restriction  will  eliminate  unnecessary  emissions.  In  addition,  if  a  device  is  designed  to  operate  pointed  downwards  in  an  enclosed  structure  such  as  a  metal  or  underground 
 storage  tank,  it  may  operate  at  the  levels  allowed  in  this  section.  See  Section  15.517  in  Appendix  D.  We  are  convinced  that  the  conservative  emission  limits  and  restrictions  we  are  adopting  for  UWB  indoor 
 devices  will  prevent  harmful  interference.  Not  only  will  indoor  operation  provide  additional  attenuation  due  to  surrounding  structure,  the  signals  from  the  UWB  transmitters  would  no  longer  be  directly  in  the 
 beam  of  high  gain  antennas,  such  as  MMDS  antennas  mounted  on  rooftops  or  aeronautical  antennas  at  airports.  Indeed,  the  majority  of  interference  problems  reported  by  NTIA  in  its  analyses  of  interference  to 
 non-  GPS  systems  concerned  outdoor  systems  and  especially  outdoor  systems  operating  at  an  elevation  of  30  meters.  136  These  provisions  will  ensure  that  even  nearby  RF  devices,  including  devices  that  also  may 
 operate  indoors,  will  not  receive  interference. 
 67.  Hand  Held  UWB  Systems.  Section  15.519  of  Appendix  D  contains  the  provisions  for  miscellaneous  UWB  devices  that  are  primarily  hand  held  and  intended  to  operate  in  a  peer-  to-  peer  mode 

 without  restriction  on  location.  Operation  among  peer-  to-  peer  devices  is  expected  to  be  a  strong  driver  for  the  development  of  UWB  technology.  We  recognize  that  the  greatest  concerns  of  interference  in  the 
 record  were  centered  about  the  potential  for  uncontrolled  proliferation  of  these  devices.  Therefore,  out  of  an  abundance  of  caution  the  limits  that  we  are  adopting  here  are  the  most  stringent  for  UWB  operation. 
 We  are  requiring  that  these  devices  operate  with  a  10  dB  bandwidth  between  3.1  GHz  and  10.6  GHz.  We  are  adopting  an  extremely  conservative  out  of  band  emission  mask  to  address  the  concerns  of  the 
 great  majority  of  commenters.  In  the  frequency  band  below  960  MHz  these  devices  are  permitted  to  emit  at  or  below  the    15.209  limits,  and  emissions  appearing  above  960  MHz  must  conform  to  the  following 
 emissions  mask: 
 Frequency  in  MHz  EIRP  in  dBm  960-  1610 

 1610-  1900  1900-  3100  -75.3  -63.3  -61.3 

 136  NTIA  Special  Publication  01-  43,  supra. 
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 3100-  10600  Above  10600  -41.3  -61.3 
 68.  Further,  we  also  require  that  these  devices  transmit  only  when  in  communication  with  an  associated  receiver.  The  transmitter  will  cease  transmission  within  10  seconds  unless  it  receives  an 
 appropriate  acknowledgment  from  the  associated  receiver,  and  the  acknowledgment  will  continue  during  the  transmission  at  10-  second  intervals.  Devices  operating  under  these  emission  levels  should  result  in 
 battery  operated,  hand  held  units  with  a  viable  range  of  about  10  to  15  meters.  The  out  of  band  emissions  are  reduced  by  10  dB  below  the  requirement  for  indoor  devices  except  in  the  GPS  bands  where  the  limit 
 is  already  approaching  the  practical  bound  on  our  ability  to  verify  compliance  by  measurement.  We  are  adopting  these  requirements  out  of  an  abundance  of  caution  and  we  believe  that  these  emission  levels  and 
 restrictions  address  the  majority  of  the  concerns  and  analyses  in  the  record.  See  Section  15.519  in  Appendix  D  for  the  specific  technical  requirements  for  these  devices. 

 69.  We  find  no  validity  to  the  statement  from  USGPSIC  that  an  operator  would  modify  the  UWB  antenna  to  change  operating  frequency  or  bandwidth  or  that  equipment  that  has  been  damaged  in 
 such  a  fashion  would  continue  to  be  operated.  We  are  aware  that  the  emitted  frequency  of  an  impulse  system  is  a  function  not  only  of  the  pulse  width  and  shape  but  also  of  the  resonant  frequency  of  the 
 antenna.  Any  major  modification  to  the  antenna  could  result  in  the  UWB  transmitter  operating  at  a  different  frequency.  However,  such  a  significant  change  would  also  render  the  equipment  unusable  as  the 
 associated  receiver  would  now  be  on  the  wrong  frequency.  Significant  phase  errors  likely  would  be  introduced  as  well.  Because  of  this,  we  expect  that  UWB  manufacturers  would  design  equipment  with 
 some  serious  thought  to  protecting  the  antenna  from  damage.  Accordingly,  we  find  no  basis  to  require  UWB  transmitters  to  be  equipped  with  filters. 

 D.  Analyses  of  Interference  Studies 
 70.  Proposal.  In  the  Notice,  the  Commission  noted  that  NTIA  and  others  were  planning  experimental  programs  to  study  the  interference  potential  of  UWB  devices.  The  Commission  encouraged 

 these  testing  programs,  believing  that  the  information  they  yielded  would  be  important  for  developing  emission  limits  for  UWB  devices.  The  establishment  of  emissions  limits  requires  a  firm  understanding  of 
 the  characteristics  of  UWB  signals,  their  impact  on  victim  receivers,  and  the  minimum  separation  distance  between  UWB  devices  and  victim  receivers.  Thus,  the  Commission  requested  parties  performing 
 interference  tests  to  consider  and  provide  information  on  receiver  susceptibility  to  UWB  signals  along  with  the  spatial  geometries  assumed  for  evaluating  potential  interference. 

 71.  Submissions.  Several  parties  submitted  analyses  of  potential  interference  to  various  radio  services  from  UWB  devices.  NTIA  137  ,  NTIA  on  behalf  on  DOT  138  ,  and  TDC  .139  provided  reports  addressing 
 potential  interference  to  GPS  receivers.  140  NTIA  presented  two  studies  regarding  the  potential  for  UWB  transmission  systems  to  cause  harmful  interference  to  U.  S.  Government  radio  operations  between  400  MHz 
 and  6000  MHz.  141  In  addition,  DOD  provided  a  mathematical  analyses  of  possible  interference  from 

 137  See  NTIA  Special  Publication  01-  45,  supra,  and  NTIA  Report  01-  384,  supra. 
 138  NTIA,  on  behalf  of  DOT,  also  submitted  a  preliminary  version  of  this  report  on  October  30,  2000. 
 139  The  study  consists  of  testing  performed  by  the  University  of  Texas  along  with  an  analysis  by  the  Applied 
 Physics  Laboratory  of  Johns  Hopkins  University.  140 
 See  Public  Notice  of  March  26,  2001,  DA  01-  753.  141 
 See  NTIA  Special  Publication  01-  43,  supra,  and  NTIA  Report  01-  383,  supra.  See,  also,  Public  Notice  of  January  24,  2001,  DA  01-  171,  requesting  additional  comments  on  this  study. 
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 UWB  operation  to  its  Space-  Ground  Link  Subsystem  (SGLS)  at  2.2-  2.3  GHz.  142  The  following  additional  reports  were  filed:  ARRL  calculated  increases  to  receiver  noise  floors  for  receivers  located  at  420  MHz 
 and  2500  MHz;  143  Motorola,  144  Sprint  PCS,  Telcordia  Technologies  and  Time  Domain  Corporation,  145  and  Qualcomm  146  performed  analyses  and  testing  of  potential  interference  to  PCS  systems;  Cisco  presented  an 
 analysis  of  interference  to  MMDS  systems;  147  and  XM  calculated  the  impact  on  Satellite  DARS  systems.  148  Comments  were  specifically  requested  on  the  NTIA,  DOT,  TDC,  and  Qualcomm  reports.  149  In  the  following 
 section,  we  summarize  each  of  these  analyses  and  present  our  findings. 
 1.  NTIA,  DOT  and  TDC  Analyses  of  Potential  Interference  to  GPS 
 72.  NTIA,  DOT,  TDC,  and  Qualcomm  performed  measurements  and  analyses  to  determine  the  UWB  emission  levels  necessary  to  prevent  interference  to  GPS  operation.  Qualcomm  conducted 

 UWB  interference  test  on  a  GPS  receiver  that  is  intended  to  provide  location  information  for  E-  911  services.  The  information  below  summarizes  various  measurement  reports  on  UWB  interactions  with 
 GPS  receivers. 
 73.  Measurements:  Initially,  NTIA  tested  two  GPS  receivers,  a  coarse/  acquisition  (C/  A)  code  tracking  receiver  architecture  that  is  representative  of  most  GPS  applications,  and  a  semi-  codeless 

 receiver  architecture  used  for  applications  that  are  less  dynamic  and  require  more  precision  such  as  surveying.  In  a  follow-  on  measurement  effort,  NTIA  also  performed  measurements  on  a  GPS  receiver 
 employing  a  narrowly  spaced  correlator  architecture  and  an  aviation  GPS  receiver  compliant  with  FAA  Technical  Standard  Order-  C129a  (TSO-  C129a)  also  employing  the  C/  A  code  receiver  architecture.  150  The 
 performance  criteria  used  to  define  and  assess  interference  to  receiver  operations  were:  (a)  break-  lock  (BL),  a  condition  that  causes  a  loss  of  signal  lock  between  the  GPS  receiver  and  the  satellite,  and  (b) 
 increase  in  reacquisition  time  (RQT),  the  amount  of  time  it  takes  a  receiver  tracking  a  GPS  signal  to  reacquire  the  signal  after  it  has  been  momentarily  removed.  NTIA  also  developed  a  representative  set  of 
 impulse  waveform  parameters  to  characterize  the  UWB  emission  environment.  The  parameters  included  four  PRFs  of  0.1,  1,  5,  and  20  MHz;  four  modulation  types  consisting  of  constant  PRF,  On-  Off  keying, 
 2%  relative  reference  dither,  and  50%  absolute  dither;  and  two  types  of  signal  gating  -  100%  and  20%;  resulting  in  32  permutations.  These  permutations  identified  the  single  source  UWB  signal  structure.  An 
 additional  set  of  5  aggregate  signal  structures  was  developed  to  investigate  how  several  UWB  devices  acting  together  would  affect  the  GPS  receiver  performance. 

 74.  NTIA  performed  testing  to  determine  the  interference  thresholds  of  the  GPS  receiver.  A  GPS  simulator  was  used  to  establish  the  GPS  receiver  operational  state.  In  the  test  constellation,  GPS 
 signals  from  a  four  satellite  constellation  (five  satellites  were  used  for  the  TSO-  C129a  compliant  receiver  in  order  to  meet  receiver  autonomous  integrity  monitoring  requirements)  based  on  ephemeris  data  taken 

 142  Filing  of  U.  S.  Department  of  Defense  submitted  10/  1/  00,  Attachment  2. 
 143  ARRL  comments  at  Appendix  A. 
 144  See  Motorola  comments  at  pg.  11-  38. 
 145  Sprint  PCS  and  TDC  joint  comments  at  Attachments  1  and  2. 
 146  See  Public  Notice  of  March  26,  2001,  DA  01-  753. 
 147  Cisco  comments,  Attachments  2  and  3. 
 148  XM  comments,  Technical  Appendix. 
 149  Other  parties  indicated  that  test  reports  would  be  filed  with  the  Commission,  but  these  have  not  been 
 forthcoming.  150 
 See  NTIA  Report  01-  389  Addendum  to  NTIA  Report  01-  384:  Measurements  to  Determine  Potential  Interference  to  GPS  Receivers  from  Ultrawideband  Transmission  Systems,  September  2001. 
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 from  an  actual  GPS  constellation  present  on  December  16,  1999.  For  the  measurements  performed  on  the  C/  A  code,  narrowly-  spaced  correlator,  and  TSO-  C129a  receivers  the  simulator  power  of  the  satellite 
 being  monitored  was  set  to  the  minimum  specification  level  of  130  dBm  at  the  GPS  receiver  input.  151  The  simulator  power  of  the  satellite  being  monitored  for  the  semi-  codeless  receiver  was  set  to  133  dBm 
 at  the  GPS  receiver  input.  One  commenter  states  that  using  the  minimum  guaranteed  signal  power  represents  an  overly  worst-  case  scenario.  152  The  commenter  also  provides  a  detailed  discussion  of  the 
 difficult  propagation  conditions  that  GPS  receivers  must  operate  in.  153  Tracking  and  acquiring/  reacquiring  satellites  in  an  open  field  with  no  obstructions  is  relatively  straightforward.  The  challenge  comes  when 
 there  is  a  partial  blockage  that  reduces  the  amount  of  signal  energy  that  reaches  the  receiver.  As  pointed  out  by  the  commenter,  the  key  factors  that  characterize  the  GPS  signal  propagation  include  multipath  and 
 blockage  from  buildings  and  foliage.  These  factors  reduce  the  received  GPS  signal  level  in  urban  and  suburban  areas  where  GPS  receivers  are  used  in  land-  based  applications.  The  received  GPS  signal  levels 
 from  unobstructed  satellites  can  be  as  much  as  7  dB  higher,  than  the  guaranteed  minimum  signal  level;  however,  it  is  the  difficult  propagation  environment  for  land-  based  GPS  receiver  applications  that  justifies 
 the  use  of  the  minimum  signal  level  in  the  establishment  of  regulatory  limits. 
 75.  Conducted  measurements  were  used  to  evaluate  the  interference  levels  on  the  GPS  receivers,  and  radiated  measurements,  using  an  anechoic  chamber  to  determine  whether  the  GPS  antennas 

 altered  the  UWB  radiated  signals  before  they  reached  the  GOS  receiver.  The  results  of  the  radiated  measurements  confirmed  that  the  GPS  antenna  does  not  cause  any  effects  to  the  portion  of  the  UWB 
 signal  within  the  GPS  operating  band  beyond  that  of  amplifying  the  signal  by  the  antenna  gain  in  the  direction  of  the  UWB  device.  One  commenter  criticized  the  NTIA  and  DOT  measurements  programs  for 
 not  including  outdoor  radiated  measurements  in  assessing  the  impact  of  UWB  devices  on  GPS  receivers.  154  We  believe  that  conducted  measurements  that  are  repeatable  in  a  controlled  environment  are 
 more  appropriate  at  this  stage  where  we  are  trying  to  set  conservative  limits  for  a  new  technology.  Since  the  ambient  noise  environment  and  the  contributions  from  multi-  path  will  change  for  each  geographic 
 location,  outdoor,  radiated  measurements  performed  in  a  specific  location  are  more  difficult  to  interpret  for  establishing  regulatory  limits  and  that  we  have  an  inadequate  record  at  this  time  for  basing  standards 
 on  such  measurements. 
 76.  The  measurements  performed  by  NTIA  also  included  collecting  amplitude  probability  distribution  (APD)  statistics,  which,  together  with  results  from  the  interference  measurements  of  the  GPS 

 receivers,  were  used  to  classify  the  UWB  signal  interference  effects  in  the  GPS  receiver  into  3  categories;  pulse-  like,  CW-  like,  and  noise-  like.  The  pulse-  like  category  was  defined  by  received  UWB  pulses  that 
 were  independent,  155  and  low  duty  cycle  (low  PRF),  and  could  not  cause  a  GPS  break-  lock  condition  within  the  available  power  of  the  UWB  test  generator.  The  CW-  like  category  was  defined  by  a  received 
 UWB  environment  composed  of  dominant  spectral  lines,  which  produced  severe  disruption  in  GPS  receiver  performance  when  one  spectral  line  aligned  with  a  C/  A  code  line  in  the  received  GPS  signal. 
 The  noise-  like  category  was  defined  as  UWB  spectra  without  dominant  lines  and  with  repeatable  measured  values  for  GPS  receiver  reacquisition  thresholds.  The  UWB  signals  and  GPS  noise  measured 
 signals  were  expressed  in  terms  of  a  20-  MHz  bandwidth  (centered  at  1575.42  MHz),  and  power 

 151  Global  Positioning  System  Standard  Positioning  Service  Signal  Specification,  Second  Edition,  GPS 
 NAVSTAR  (June  2,  1995)  at  pg.  18.  152 
 TDC  Comments  in  response  to  Public  Notice  at  pg.  40.  153 
 Id  at  pg.  49.  154 
 Id  at  pg.  36.  155 
 Pulses  are  independent  when  the  filter  bandwidth  is  greater  than  the  pulse  repetition  rate.  To  remain  independent  the  minimum  pulse  repetition  period  of  a  dithered  signal  must  be  greater  than  the  duration  of  the  filter 

 impulse  response. 
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 measurements  were  expressed  as  RMS  power  levels.  The  measurements  produced  values  of  the  RMS  power  level  for  interference  using  BL  and  RQT  thresholds  for  all  of  the  32  UWB  signal  variations  and  5 
 aggregate  UWB  signal  cases. 
 77.  NTIAs  classification  of  the  UWB  signals,  as  they  existed  in  the  GPS  receivers  tested,  is  similar  to  classifications  for  general  interference  to  GPS  made  by  the  RTCA  (pulsed,  CW,  and  broadband 

 noise)  and  the  ITU-  R  (CW  and  broadband  noise).  156  .  The  ITU-  R  and  the  RTCA  have  both  derived  permissible  interfering  signal  limits  for  each  of  these  classes  of  GPS  interference.  For  the  case  of  in-  band 
 pulsed  interference,  the  RTCA  derived  limit  is  a  peak  power  of  +20  dBm  for  pulse  widths  less  than  1  ms  and  pulse  duty  cycles  less  than  10%.  For  the  in-  band  CW  interference  case,  both  the  RTCA  and  the  ITU-R 
 interference  limits  are  defined  as  120.5  dBm  for  GPS  receivers  operating  in  the  tracking  mode.  157  For  in-  band  broadband  noise  interference,  both  the  RTCA  and  the  ITU-  R  limits  are  -110.5  dBm/  MHz  for  GPS 
 receivers  operating  in  the  tracking  mode.  158  The  NTIA  measurement  and  analysis  results  are  consistent  with  these  values.  These  RTCA  and  ITU-  R  limits  are  based  on  a  minimum  available  GPS  C/  A  code 
 signal  level  of  130  dBm  with  the  GPS  receiver  antenna  gain  assumed  to  be  -4.5  dBi.  159  The  RTCA  and  ITU-  R  interference  limits  are  based  on  a  Minimum  Operational  Performance  Standard  for  GPS  receivers 
 used  for  Category  I/  II/  III  precision  approaches. 
 78.  NTIA  demonstrated  that  independent  UWB  pulses  of  sufficient  amplitude  would  saturate  one  or  more  elements  in  the  GPS  receiver  during  the  pulse  period.  If  the  pulses  are  relatively  short,  and 

 produce  an  impulse  response  at  the  output  of  the  filter,  and  are  of  a  relatively  low  duty  cycle,  they  will  not  seriously  degrade  GPS  performance.  Further,  the  interference  effect  is  independent  of  the  pulse 
 amplitude  as  long  as  the  amplitude  is  below  the  receiver  peak  pulse  power  limit  (approximately  +20  dBm).  NTIA  concluded  that  GPS  performance  is  relatively  robust  to  pulse-  like  UWB  emissions.  The 
 NTIA  measurements  for  the  C/  A  code  receiver  architecture  show  that  a  UWB  signal  with  a  PRF  of  100  kHz  160  causes  a  low-  duty  cycle  pulse-  like  interference  effect  that  does  not  degrade  GPS  receiver 
 performance.  The  measurements  performed  by  NTIA  for  the  narrowly  spaced  correlator  and  TSO-  C-129a  receivers,  which  use  the  C/  A  code  architecture,  also  show  this  low  duty  cycle,  pulse-  like 
 interference  effect. 
 79.  NTIA  also  performed  measurements  of  UWB  interference  to  a  semi-  codeless  GPS  receiver.  The  measured  susceptibility  values,  based  on  the  RQT  performance  criterion,  are  for  a  variety 

 of  UWB  characteristics.  The  GPS  receiver  performance  criterion  for  RQT  is  a  sharp  increase  in  the  average  time  to  reacquire  a  GPS  signal  that  has  been  interrupted  for  ten  seconds.  This  average  time  was 
 determined  by  measuring  the  reacquisition  time  for  each  of  ten  trials  (for  the  same  set  of  test  conditions)  and  then  computing  the  average  time  of  the  successful  reacquisitions.  That  is,  if  the  receiver  was  not  able 
 to  reacquire  within  the  time  allowed  for  a  trial,  this  trial  was  not  considered  in  the  determination  of  average  reacquisition  time.  The  RQT  threshold  value  was  determined  by  engineering  judgment  by 
 observing  a  plot  of  average  reacquisition  time  and  deciding  at  what  UWB  input  signal  level  there  was  a 
 156  NTIA  Special  Publication  01-  45,  supra,  at  pg.  2-  8. 
 157  ITU-  R  Recommendation  M.  1477,  Technical  and  Performance  Characteristics  of  Current  and  Planned 
 Radionavigation-  Satellite  Service  (Space-  to-  Earth)  and  Aeronautical  Radionavigation  Service  Receivers  to  Be  Considered  in  Interference  Studies  in  the  Band  1559-  1610  MHz  (2000),  at  Tables  1  and  2.  As  noted  in  footnote  2  to 

 these  tables,  the  interference  threshold  already  takes  into  account  the  effects  of  GPS  intra-  system  interference  based  on  random  code  analysis.  This  threshold  value  must  account  for  all  other  aggregate  interference. 
 158  Id. 
 159  Document  Number  RTCA/  DO-  229B,  Minimum  Operational  Performance  Standard  for  GPS/  Wide  Area 
 Augmentation  System  Airborne  Equipment  (January,  1996).  Recommendation  ITU-  R  M.  1477,  supra,  at  ANNEX  1,  Section  3-  2. 

 160  These  low  PRFs  are  found  in  most  of  the  proposed  GPR  systems. 
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 sharp  increase  in  reacquisition  time.  In  general,  this  sharp  increase  was  more  evident  for  the  UWB  signals  involving  higher  PRFs  (i.  e.,  5  and  20  MHz)  and  was  more  a  judgment  for  the  lower  PRF 
 conditions.  161 
 80.  The  DOT  sponsored  measurements  considered  a  UWB  signal  with  a  PRF  of  100  kHz  and  came  to  the  same  conclusion  as  NTIA.  Thus  as  long  as  the  PRF  of  the  UWB  emission  is  no  greater  than, 

 100  kHz,  and  the  output  level  of  the  UWB  emission  is  low  enough  so  as  not  to  overload  the  front  end  of  the  GPS  receiver,  interference  to  GPS  from  UWB  operation  is  unlikely.  Based  on  the  test  data,  UWB 
 devices  could  operate  at  the  Part  15  general  emission  limits,  provided  the  PRF  does  not  exceed  100  kHz,  without  causing  interference  to  GPS  reception.  Thus  from  the  GPS  protection  viewpoint,  GPRs  with 
 PRFs  less  than  100  kHz  are  not  an  interference  concern. 
 81.  For  the  measurements  of  the  C/  A  code  receiver  architecture,  NTIA  classified  19  of  the  32  UWB  signal  permutations  in  the  pulse-  like  category.  The  majority  of  the  PRF  values  were  100  kHz  (8 

 cases)  and  1  MHz  (7  cases),  however  two  of  the  5  MHz  PRF  (2%  relative  and  50%  absolute  dither  with  20%  gate),  and  one  20  MHz  PRF  (2%  relative  dither,  20%  gate)  produced  pulse-  like  interference  effects. 
 The  NTIA  measurements  confirmed,  as  theory  would  predict,  that  there  is  a  relationship  between  the  interference  effect  and  the  receiver  bandwidth.  For  example,  some  of  the  UWB  signals  (particularly 
 among  the  1  MHz  PRF  signals)  that  produced  pulse-  like  interference  effects  in  the  wider  band  GPS  receivers  (the  10  MHz  C/  A  code  and  16  MHz  narrowly-  spaced  correlator  receivers)  produced  a  response 
 characteristic  of  the  more  disruptive  noise-  like  or  CW-  like  interference  effects  in  the  narrower  bandwidth  receiver  (2  MHz  TSO-  C129a).  As  the  PRF  of  the  UWB  emission  increases  above  1  MHz,  the 
 interference  to  the  GPS  receiver  can  be  classified  as  either  noise-  like  or  CW-  like.  The  noise  like  signal  permutations  included  the  5  and  20  MHz  PRF,  100%  gated  waveform  with  2%  relative  or  50%  absolute 
 dithering.  Among  these  four  noise-  like  cases,  the  worst-  case  measured  interference  threshold  for  the  C/  A  code  receiver  was  95  dBm/  20  MHz  (-  108  dBm/  MHz)  corresponding  to  the  20  MHz  PRF,  with  50% 
 absolute  dithering  signal.  Nine  of  the  32  UWB  signal  permutations  were  categorized  as  CW-  like.  There  were  four  5  MHz  and  four  20  MHz  PRF  cases  and  one  1  MHz  PRF  signal  set  that  resulted  in  CW-  like 
 GPS  interference  effects.  Among  these  9  CW-  like  cases,  the  worst-  case  interference  threshold  measured  for  the  C/  A  code  receiver  was  99.5  dBm/  20  MHz.  The  adjustments  to  convert  this  value  to  the  power 
 level  for  a  single  spectral  line  in  a  one  MHz  bandwidth  include  a  3  dB  reduction  for  the  division  of  power  between  discrete  spectral  lines  and  the  continuous  spectrum  for  on-  off  keying  (OOK),  a  7  dB  reduction  to 
 account  for  the  20%  gate-  on  time  relative  to  total  time  of  20  milliseconds,  and  a  7  dB  reduction  to  adjust 
 161  Of  particular  concern  for  the  interference  protection  of  the  semi-  codeless  GPS  receiver  is  the  reacquisition 
 data  point  listed  for  the  UWB  signal  with  a  100  kHz,  2%  relative  dither  and  20%  gating.  The  listed  value  is  -88  dBm/  20  MHz.  This  single  value  would  indicate  the  semi-  codeless  receiver  is  susceptible  to  low  PRF  UWB 

 interference.  This  single  value  is  at  least  17  dB  lower  than  the  other  listed  values  for  a  100  kHz  PRF  UWB  signal.  This  17  dB  difference  includes  a  7  dB  adjustment  to  determine  the  average  interference  power  for  the  20%  gated 
 signal.  Because  this  17  dB  difference  is  significant  in  determining  interference  protection  requirements,  a  further  review  of  this  data  point  was  carried  out.  The  measured  data  plots  for  all  the  100  kHz  PRF,  20%  gated  UWB  signal 
 cases  for  the  semi-  codeless  receiver  tests  were  reviewed.  This  resulted  in  reviewing  four  data  plots  for  reacquisition  tests  from  the  measured  data  report.  As  previously  stated  the  reacquisition  threshold  was  determined  through  a 
 judgment  as  to  the  power  level  where  a  sharp  increase  in  reacquisition  time  occurred.  For  three  of  the  data  plots,  the  previous  judgment  was  that  no  sharp  increase  was  observed  over  the  range  of  measured  interference  power  levels. 
 Only  in  the  case  of  concern  (100  kHz  with  2%  relative  dither  and  20%  gating)  was  a  reacquisition  threshold  selected.  In  retrospect,  because  the  curves  are  all  similar,  a  comparative  review  of  the  data  across  the  four  cases 
 would  indicate  that  a  reacquisition  threshold  should  not  have  been  selected  over  the  range  of  UWB  signal  powers  measured  for  the  100  kHz  PRF,  2%  relative  dither  and  20%  gating  case.  Thus,  the  entry  in  Table  2-  2  of  NTIA 
 Special  publication  01-  45  should  be  [-  66]  rather  than  -88.  The  [-  66]  shows  that  this  was  the  limit  of  the  power  available  in  the  test  setup  and  the  effect  of  interest  (the  reacquisition  threshold)  was  not  observed.  This  GPS  receiver 
 performance,  in  the  presence  with  low  PRF  UWB  interfering  signals,  is  in  agreement  with  the  C/  A  code  receiver  architecture  results. 
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 for  a  single  spectral  line  that  is  modulated  by  a  sinc  function  by  the  gating  period,  producing  116.  5  dBm.  162  The  measured  level  at  which  interference  occurred  to  the  GPS  C/  A  code  receiver  was  8  dB  less 
 for  a  CW-  like  UWB  signal  than  for  the  noise-  like  UWB  signal.  163  This  measured  difference  is  in  agreement  with  the  RTCA  and  ITU-  R  standards  noted  above  which  identify  a  10  dB  difference  for  the 
 two  interference  effects. 
 82.  Analysis:  In  order  to  calculate  the  maximum  allowable  EIRP  for  a  UWB  device,  a  source-  path-  receiver  analysis  must  be  performed.  The  basic  parameters  that  must  be  defined  for  this  type 

 of  analysis  are  the  receiver  interference  threshold,  the  source  output  power  and  antenna  gain,  the  propagation  path  between  the  transmitter  and  receiver,  and  the  antenna  gain  of  the  receiver  in  the 
 direction  of  the  source  transmitter.  The  data  obtained  from  the  measurements  performed  by  NTIA  define  the  interference  threshold  level  at  the  input  of  the  GPS  receiver  as  a  function  of  UWB  signal  structure 
 (e.  g.,  power,  PRF,  modulation  scheme)  for  each  of  the  GPS  receiver  architectures  examined.  The  EIRP  of  an  UWB  device  can  be  estimated  by  the  Part  15  emission  limit  to  which  it  is  subject.  However,  this  EIRP 
 thus  derived  is  in  most  practical  cases  an  overestimate,  particularly  when  the  receiver  of  interest  has  a  bandwidth  which  is  narrow  compared  to  the  difference  between  the  upper  and  lower  frequency  of  a 
 emission  limit. 
 83.  In  the  case  of  the  emission  limits  in  Appendix  D,  the  bracket  containing  the  GPS  band  is  960-  1610  MHz  with  a  total  bandwidth  of  650  MHz.  Part  15  devices  are  measured  for  approval  purposes 

 using  the  methodology  contain  in  ANSI  Standard  C63.  4.  164  This  methodology  checks  the  limit,  expressed  in  field  strength  units,  over  the  whole  bandwidth  of  the  bracket  and  over  a  surface  3  meters  away  from  the 
 device  under  test  with  measurement  height  ranging  from  1  to  4  meters.  Furthermore,  the  device  is  measured  over  a  conducting  surface  that  causes  reflections  of  emissions  to  reach  the  antenna  in  addition 
 to  direct  rays  from  device  under  test.  This  multipath  contribution  to  the  measured  field  strength  means  that  the  measured  field  strength  corresponds  to  an  EIRP  4-  5  dB  higher  than  a  mathematical  conversion 
 from  field  strength  to  EIRP  would  indicate.  Furthermore  the  fact  that  the  highest  field  strength  measurement  over  a  cylinder  3  meters  in  radius  and  3  meters  high  and  over  the  whole  bandwidth  of  a 
 bracket  is  used  for  compliance  comparison,  leads  to  an  additional  overestimate  compared  with  the  signal  that  might  be  emitted  from  a  UWB  device  in  a  specific  direction  and  at  a  specific  frequency  measurement 
 with  a  1  MHz  bandwidth.  For  the  following  analysis  to  determine  UWB  emission  limits  we  will  use  the  worst  case,  but  probably  unrealistic,  assumption  that  the  EIRP  in  the  direction  of  the  GPS  receiver  or  any 
 other  victim  receiver  is  the  same  as  implied  by  compliance  measurement.  This  is  necessary  at  this  time  because  we  do  not  have  reliable  information  in  the  record  concerning  the  evenness  of  the  spectral 
 emissions  over  frequency  and  the  variability  of  UWB  antenna  patterns  with  frequency  and  direction. 
 84.  In  order  to  make  reasonable  assumptions  regarding  the  remaining  values  needed  for  the  analysis,  information  regarding  how  the  transmitter  and  receiver  can  interact  within  their  operating 

 environment  is  necessary.  Collectively,  this  information  defines  an  operational  scenario,  which  establishes  how  close  the  two  systems  may  come  to  one  another  under  actual  operating  conditions,  and 
 the  likely  orientation  of  the  antennas.  This  information  is  then  used  to  compute  the  propagation  loss  and  the  receive  antenna  gain  in  the  direction  of  the  transmitter.  The  operational  scenario  can  also  be  used  to 
 determine  the  applicability  of  factors  such  as  building  attenuation,  multiple  transmitters,  and  safety  margins. 

 162  NTIA  Special  Publication  01-  45,  supra,  at  pg.  2-  12. 
 163  Our  discussion  in  this  section  primarily  is  directed  to  noise-  like  UWB  emissions.  Additional  protection 
 will  be  provided  to  GPS  reception  of  CW-  like  emissions  to  accommodate  the  8  dB  difference  measured  by  NTIA  and  the  10  dB  specified  in  the  RTCA  and  ITU-  R  standards. 

 164  See  47  C.  F.  R.    15.  31(  a)(  6). 
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 85.  NTIA,  RTCA,  and  the  USGPSIC  performed  analysis  to  compute  the  maximum  allowable  EIRP  for  the  UWB  devices  with  the  GPS  receiver  and  UWB  device  for  different  operational  scenarios. 
 NTIA  hosted  a  series  of  open  public  meetings  to  develop  operational  scenarios  to  be  considered.  The  meetings  were  announced  in  the  Federal  Register  and  participation  was  encouraged  within  the  UWB  and 
 GPS  communities  and  among  the  interested  Federal  agencies.  Specific  proposals  for  operational  scenarios  to  be  considered  included  GPS  receivers  used  in  the  following  applications:  land-  based  (e.  g., 
 public  safety,  emergency  response  vehicle  navigation,  geographic  information  systems,  precision  machine  control);  maritime  navigation  (in  constricted  waterways,  harbors,  docking,  and  lock  operations);  railway 
 operations  (positive  train  control);  surveying;  and  aviation  (en-  route  navigation  and  non-  precision  approach).  The  input  received  at  the  public  meetings  was  used  by  NTIA  to  develop  the  operational 
 scenarios  considered  in  their  analysis.  RTCA  Working  Group  6  developed  operational  scenarios  for  GPS  receivers  used  in  Category  I,  II,  and  III  precision  approach  landings.  The  USGPSIC  developed  an 
 operational  scenario  for  an  E-  911  GPS  receiver.  Since  the  Notice  did  not  specify  any  operating  restrictions  for  UWB  devices,  the  operational  scenarios  considered  both  indoor  and  outdoor  operation  of 
 UWB  devices.  These  operational  scenarios  are  the  developers  best  estimates  of  acceptable  geometries  between  GPS  receivers  and  UWB  devices.  However,  the  scenarios  do  not  have  the  legal  status  of  law  or 
 regulation  and  our  willingness  to  use  them  for  this  analysis  is  based  mostly  on  the  absence  of  other  standards  that  reflect  a  broad  consensus  and  a  balancing  of  all  public  interests.  Spectrum  management  is 
 a  complex  subject  and  interference  protection  goals  in  general  must  consider  both  the  benefits  of  authorizing  new  emitters  as  well  as  the  interference  risk  to  other  systems. 

 86.  There  are  two  operational  scenarios  proposed  on  the  record  that  serve  as  the  limiting  scenarios  for  establishing  the  emission  limits  for  UWB  devices  operating  indoors:  1)  the  land-  based 
 multiple  UWB  device  operational  scenario  developed  by  NTIA  and  2)  the  E-  911  operational  scenario  developed  by  the  USGPSIC.  The  following  paragraphs  provide  a  detailed  discussion  of  these  operational 
 scenarios. 
 87.  The  first  limiting  operational  scenario  for  the  indoor  use  of  UWB  devices  is  where  there  are  several  UWB  devices  operating  inside  of  a  building  and  the  GPS  receiver  is  operating  outdoors.  The 

 following  table  provides  an  overview  of  the  technical  factors  for  noise-  like  interfering  UWB  signals  considered  in  the  analysis  for  this  operational  scenario.  In  order  to  err  on  the  conservative  side,  worst  case 
 assumptions  have  been  used  for  most  parameters,  as  advocated  and  explained  by  NTIA. 

 Table  1  Technical  Factors  Considered  for  Indoor  UWB  Interference  to  GPS 

 Parameter  Value  Value  GPS  Receiver  Interference  Susceptibility  (dBm/  MHz) 
 (Performance  Metric)  -102.5  (BL)  -108  (RQT)  Propagation  Loss  (dB) 
 (Minimum  Distance  Separation  (m))  55  (8.6)  55  (8.6)  GPS  Receive  Antenna  Gain  (dBi)  -3  -3 
 UWB  Device  Interference  Allotment  (dB)  (Percentage  UWB)  -3  (50)  -3  (50) 
 Allotment  for  Multiple  UWB  Devices  (dB)  (Number  of  Devices)  -6  (4)  -6  (4) 
 Manufacturer  Variation  (dB)  -3  -3  Average  Building  Attenuation  (dB)  9  9 
 Allowance  for  Acquisition  (dB)  -6  0  Maximum  Allowable  EIRP  (dBm/  MHz)  -59.5  -59 
 47  C.  F.  R.  15.  209  Emission  Limit  (dBm/  MHz)  -41.3  -41.3  Additional  Attenuation  Required  (dB)  18.2  17.7 
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 88.  The  UWB  emission  limit  recommended  in  the  above  table  is  calculated  by  adding  the  values  in  the  columns.  As  shown  in  the  table,  for  noise-  like  UWB  signals  an  additional  18  dB  of 
 attenuation  below  the  47  C.  F.  R.  15.209  emission  limit  is  necessary  to  protect  the  GPS  receiver  under  the  conservative  assumptions  in  this  operational  scenario.  The  following  paragraphs  will  provide  a  detailed 
 discussion  of  each  of  the  technical  factors  considered  in  this  operational  scenario. 
 89.  The  GPS  interference  susceptibility  levels  used  in  this  analysis  correspond  to  the  break-lock  and  reacquisition  performance  metrics  of  the  GPS  receiver.  As  discussed  earlier,  the  GPS  receiver 

 interference  susceptibility  referenced  to  the  input  of  the  receiver  was  obtained  from  the  single  source  measurements  performed  by  NTIA.  The  values  used  in  this  analysis  are  based  on  the  UWB  signal 
 structure  that  causes  the  most  susceptible  noise-  like  interference  threshold  that  was  measured  by  NTIA. 
 90.  The  propagation  loss  is  computed  using  the  minimum  distance  separation  between  the  GPS  receiver  and  the  UWB  device  as  defined  by  the  operational  scenario  considered.  For  this  operational 

 scenario  the  minimum  distance  separation  is  computed  from  the  slant  range  with  the  GPS  receiver  located  5  meters  from  the  building  and  the  UWB  device  7  meters  above  the  GPS  receiver.  The  computed 
 minimum  distance  separation  is  8.6  meters.  For  this  distance  separation  the  free  space  propagation  model  is  applicable.  One  commenter  suggests  that  a  factor  for  loss  due  to  vegetation  be  included  in  the 
 analysis.  165  Although  such  a  factor  may  be  applicable  in  other  operational  scenarios,  NTIA  does  not  believe  that  it  is  appropriate  in  this  case  and  that  it  should  not  be  included  in  the  analysis.  The  commenter 
 also  suggests  that  a  factor  be  included  for  scattering  loss  that  would  result  from  the  fact  that  most  of  the  world  is  cluttered  with  objects  that  will  reflect  the  UWB  signals  and  create  frequency  selective  nulls.  166 
 Signal  scattering  similar  to  the  effects  of  multi-  path  is  difficult  to  predict  and  are  highly  dependent  on  the  surrounding  obstacles.  Since  there  is  no  way  to  accurately  predict  the  types  of  obstacles  that  exist  in  a 
 given  area,  the  inclusion  of  such  a  factor  in  this  analysis  may  not  be  appropriate  given  the  lack  of  operational  experience  with  UWB. 

 91.  The  UWB  devices,  which  are  indoors,  in  this  operational  scenario,  are  located  above  the  GPS  receiver,  which  is  outside.  The  antenna  model  used  by  NTIA  for  the  GPS  receiver  indicates  that  the 
 receive  antenna  gain  is  3  dBi.  The  antenna  for  the  UWB  device  is  assumed  to  be  omnidirectional.  One  commenter  suggested  that  the  antenna  gain  of  the  UWB  device  in  the  direction  of  the  GPS  receiver  be 
 reduced  by  2  dB  to  account  for  off-  axis  antenna  alignment.  167  Another  commenter  stated  that  in  the  analysis  of  aggregate  interference  to  airborne  GPS  receivers  it  is  appropriate  to  reduce  the  gain  of  the 
 UWB  device  based  on  the  elevation  angle.  168  The  commenter  states  that  most  UWB  applications  will  employ  omnidirectional  antennas  that  will  provide  essentially  uniform  coverage  in  the  horizontal 
 direction  and  in  the  vertical  direction  for  low  elevation  angles.  169  The  commenter  recommends  that  the  antenna  gain  of  the  UWB  device  be  reduced  by  approximately  40  dB  to  4  dB  respectively  for  elevation 
 angles  from  the  vertical  down  to  45  degrees.  170  At  the  lower  elevation  angles,  the  commenter  does  not  recommend  a  reduction  in  the  UWB  device  antenna  gain.  We  agree  that  it  would  be  appropriate  to  include 
 such  a  factor  if  the  UWB  devices  were  employing  directional  antennas  and  the  locations  of  the  devices 
 165  TDC  Comments  in  Response  to  Public  Notice  at  pg.  64. 
 166  Id. 
 167  Id. 
 168  Comments  of  XtremeSpectrum,  Inc.,  On  Issues  of  Interference  Into  Global  Positioning  System  Receivers 
 (April  25,  2001)  at  pg.  21.  169 
 Id.  170 
 Id. 
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 were  known.  However,  it  may  not  be  appropriate  to  include  an  off-  axis  antenna  alignment  factor  in  the  analysis  of  this  operational  scenario,  where  omnidirectional  antennas  might  to  be  employed.  Off-  axis 
 discrimination  is  typically  employed  when  analyzing  stations  in  the  fixed  radio  service,  for  example,  where  the  locations  of  the  transmitters  and  antenna  pointing  angles  are  known.  Since  the  locations,  the 
 types  of  antennas  being  employed,  and  the  antenna  pointing  angles  of  the  UWB  devices  are  all  unknowns;  it  may  be  inappropriate  to  include  a  factor  for  off-  axis  antenna  alignment  in  this  analysis.  An  off-  axis 
 antenna  alignment  factor  could  be  applied  in  an  operational  scenario  examining  aggregate  interference  to  an  airborne  receiver  from  a  large  number  of  land-  based  UWB  devices,  such  as  in  an  en-  route  navigation 
 operational  scenario.  However,  it  may  not  be  appropriate  to  include  such  a  factor  in  the  analysis  of  this  operational  scenario  based  on  the  record. 

 92.  One  commenter  states  that  antenna  polarization  mismatch  loss  should  be  included  in  the  analysis  to  minimize  the  interference  effects  of  UWB  devices  to  GPS  receivers.  171  Polarization  mismatch 
 loss,  also  referred  to  as  polarization  discrimination  or  polarization  isolation,  is  the  ratio  at  a  receiving  point  between  received  power  in  the  expected  polarization  and  received  power  in  a  polarization 
 orthogonal  to  it  from  a  wave  transmitted  with  a  different  polarization.  Polarization  mismatch  is  a  common  technique  used  in  sharing  the  same  frequency  for  fixed  point-  to-  point  microwave  systems  and 
 fixed  satellite  earth  stations.  The  key  factor  being  that  the  transmitter  and  receiver  antennas  are  fixed  and  their  polarization  are  known.  Moreover,  the  polarization  of  an  antenna  remains  relatively  constant 
 throughout  the  main  lobe  of  the  antenna  pattern,  but  varies  considerably  in  the  minor  lobes.  172  In  practice,  polarization  of  the  radiated  energy  varies  with  the  direction  from  the  center  of  the  antenna,  such  that 
 different  parts  of  the  antenna  pattern  and  different  sidelobes  have  different  polarizations.  173  This  is  also  true  for  GPS  antennas  where  in  the  mainbeam  the  polarization  is  circular,  but  outside  the  mainbeam  in  the 
 lower  elevation  angles  the  polarization  is  nearly  linear.  Since  the  locations  of  the  UWB  devices,  and  polarizations  are  unknown  at  this  time  we  do  not  believe  that  a  factor  for  polarization  mismatch  loss 
 should  be  included  in  the  analysis. 
 93.  In  addition  to  the  potential  interference  from  UWB  devices,  several  other  potential  sources  of  interference  to  GPS  receivers  have  been  identified.  These  potential  sources  of  interference 

 include  but  are  not  limited  to:  1)  adjacent  band  interference  from  mobile-  satellite  service  Mobile  Earth  Terminals  (METs);  2)  harmonics  from  television  transmitters;  3)  spurious  emissions  from  700  MHz 
 public  safety  base,  mobile,  and  portable  transmitters;  and  4)  spurious  emissions  including  harmonics  from  700  MHz  commercial  base,  mobile,  and  portable  transmitters.  Multiple  sources  of  interference,  which 
 might  individually  be  tolerated  by  a  GPS  receiver,  may  combine  to  create  an  aggregate  interference  level  that  could  prevent  the  reliable  reception  of  the  GPS  signal.  The  emission  limit  of  the  MSS  METs,  700 
 MHz  public  safety  and  commercial  transmitters  is  40  dBm/  MHz  for  noise-  like  interference.  The  zone  of  interference  of  each  of  these  transmitters  could  be  as  much  as  a  circle  of  30-  meter  (100-  foot)  radius,  if  it 
 emits  out-  of-  band  radiation  at  the  limit.  The  emission  from  digital  television  (DTV)  transmitters  is  110  dBc  and  will  result  in  a  zone  of  interference  that  is  as  much  as  a  circle  of  270  meters  (884-  foot)  radius  at 
 the  same  height  as  the  antenna.  As  a  consequence  these  transmitters  do  not  have  to  be  located  next  to  a  GPS  receiver  to  disrupt  signal  reception  in  land-  based  applications.  In  this  conservative  operational 
 scenario  one  half  of  the  total  allowable  interference  budget  is  allotted  to  UWB  devices  and  the  other  half  is  allotted  to  all  other  interfering  sources  combined.  The  factor  for  UWB  device  interference  allotment  is 
 computed  from  10  Log  (UWB  interference  allotment  ratio).  For  a  UWB  device  interference  allotment  of  50%  (a  ratio  of  0.5),  a  3  dB  factor  is  included  in  this  analysis.  One  commenter  argued  against  including  a 
 factor  for  interference  allotment  in  the  analysis.  174  However,  their  argument  is  at  odds  with  their  other 
 171  TDC  Comments  in  Response  to  Public  Notice  at  pg.  64. 
 172  Antenna  Engineering  Handbook,  R.  C.  Johnson,  H.  Jasik  (Second  Edition)  at  pg.  1-  7. 
 173  Antenna  Analysis,  E.  A.  Wolff  (1966)  at  pg.  17 
 174  TDC  Comments  in  Response  to  Public  Notice  at  pg.  56. 
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 comments,  wherein  they  acknowledge  that  there  may  be  sources  of  interference  such  as  incidental  and  unintentional  radiators,  as  well  as  licensed  transmitters  with  spurious  emissions  in  the  GPS  bands.  175  The 
 use  of  allotments  for  multiple  sources  of  interference  is  not  a  new  concept  in  studies  examining  interference  from  one  radio  service  to  another.  For  example,  ITU-  R  Recommendation  F.  1094-  1  specifies 
 an  interference  allotment  of  89%  for  transmitters  of  the  same  radio  service,  an  interference  allotment  of  10%  for  radio  transmitters  in  other  radio  services,  and  a  1%  interference  allotment  for  all  other  sources 
 (e.  g.,  unlicensed  transmitters).  176  This  is  also  consistent  with  ITU-  R  Recommendation  M.  1477,  which  states  that  when  there  is  a  potential  for  more  than  one  source  of  interference  at  the  same  time,  it  will  be 
 necessary  to  apportion  the  interference  threshold  among  the  potential  interference  sources.  177  Since  the  GPS/  UWB  measurements  that  are  part  of  the  public  record  in  this  proceeding  did  not  include  other 
 potential  sources  of  interference,  it  may  be  appropriate  to  include  a  factor  in  the  analysis  to  take  them  into  account.  Out  of  an  abundance  of  caution,  we  shall  do  so  here  but  may  request  comments  in  future 
 proceedings  on  appropriate  interference  modeling. 
 94.  The  factor  for  multiple  UWB  devices  was  obtained  from  the  multiple  source  (aggregate)  measurements  performed  by  NTIA.  The  measurements  performed  by  NTIA  verified  that  if  the  individual 

 signals  cause  an  interference  effect  that  is  noise-  like,  the  interference  effect  of  the  multiple  noise-  like  signals  is  noise-  like.  Based  on  the  measurements,  for  UWB  signal  permutations  that  have  been 
 characterized  as  causing  noise-  like  interference,  a  factor  of  10  Log  (number  of  UWB  devices)  is  included  in  the  analysis.  Based  on  the  record,  it  is  unclear  whether  this  modeling  of  cumulative  effects  of  multiple 
 spatially  separated  UWB  devices  will  be  representative  of  typical  UWB  environments.  However,  erring  again  on  the  side  of  conservatism  in  order  to  protect  GPS  in  the  near  future  we  are  accepting  NTIAs 
 analysis  of  multiple  UWB  device  effects  at  this  time. 
 95.  One  commenter  recommends  that  an  activity  factor  of  3  dB  be  included  in  the  analysis  to  account  for  the  fact  that  UWB  devices  will  not  be  transmitting  continuously.  178  The  factor  of  3  dB  would 

 indicate  that  each  UWB  device  is  transmitting  50%  of  the  time.  The  inclusion  of  an  activity  factor  may  be  appropriate  when  there  are  a  large  number  of  UWB  devices  considered  in  the  operational  scenario. 
 The  activity  factor  is  also  dependent  upon  the  UWB  application.  Since  there  are  only  four  UWB  devices  in  this  operational  scenario  and  it  is  not  possible  to  accurately  estimate  representative  values  of  activity 
 factors  at  this  time,  we  will  not  use  an  activity  factor  in  this  analysis  (i.  e.,  the  UWB  devices  will  be  continuously  transmitting). 

 96.  A  2001  GPS  Receiver  Survey  lists  64  different  manufacturers  of  GPS  receivers.  179  The  survey  lists  approximately  500  different  models  of  GPS  receivers  representing  the  C/  A  code,  semi-codeless, 
 and  narrowly  spaced  correlator  receiver  architectures.  The  NTIA  measurements  included  one  receiver  from  each  of  the  three  GPS  architectures.  Based  on  the  NTIA  measurements,  the  results  of  the 
 other  measurement  efforts,  and  the  analyses  of  the  data  that  is  part  of  the  public  record  in  this  proceeding,  initial  engineering  modeling  of  the  interference  effects  of  UWB  signals  on  the  different  GPS  receiver 
 architectures  has  emerged.  However,  the  number  of  different  models  of  GPS  receivers  and  manufacturers  considered  in  the  current  measurement  efforts  may  not  completely  represent  the  performance  of  all  the 

 175  Id.  at  pg.  44. 
 176  ITU-  R  Recommendation  F.  1094-  1,  Maximum  Allowable  Error  Performance  and  Availability  Degradations 
 to  Digital  Radio-  Relay  Systems  Arising  from  Interference  from  Emissions  and  Radiations  from  Other  Sources.  177 
 ITU-  R  M.  1477  at  Annex  5.  178 
 TDC  Comments  in  Response  to  the  Public  Notice  at  pg.  64.  179 
 GPS  World  Receiver  Survey,  GPS  World  Magazine,  January  2001,  at  pg.  32. 
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 GPS  receivers  currently  being  manufactured.  There  may  be  differences  in  hardware,  firmware,  180  or  software  (e.  g.,  tracking  and  acquisition  algorithms)  employed  in  the  receivers  that  were  not  considered  in 
 the  current  measurement  efforts.  There  may  be  differences  in  the  models  produced  by  the  same  manufacturer  as  well  as  between  receivers  produced  by  different  manufacturers.  Therefore,  the  inclusion 
 of  a  factor  in  the  analysis  to  account  for  these  possible  differences  is  reasonable  at  this  time.  Based  on  an  analysis  performed  by  NTIA  of  the  data  that  is  on  the  public  record  in  this  proceeding,  the  range  of  data 
 indicates  that  the  more  susceptible  interference  thresholds  are  within  3  dB  of  the  median.  181  One  commenter  objected  to  the  inclusion  of  the  3  dB  factor  for  manufacturer  variation.  182  The  commenter 
 stated  that  the  industry  would  not  accept  a  3  dB  variance  from  the  stringent  specifications  required  by  the  aviation  and  surveying  receivers.  183  With  the  exception  of  the  aviation  community,  NTIA  indicates  that  it 
 is  unaware  of  any  specifications  for  GPS  receivers.  The  NTIA  analysis  included  this  factor  to  take  into  account  the  small  number  of  GPS  receivers  considered  in  all  of  the  measurement  efforts.  The  analysis 
 performed  by  JHU/  APL  also  acknowledged  that  there  are  differences  in  GPS  receivers.  Specifically  JHU/  APL  concluded  that  variations  in  the  measurements  of  performance  due  to  different  GPS  receivers 
 are  greater  than  those  due  to  the  operating  modes  of  the  UWB  tested  devices.  JHU/  APL  further  concluded  that  the  impact  of  UWB  devices  on  all  GPS  receivers  could  not  be  assessed  using  a  single  GPS 
 receiver.  184  Based  on  the  analysis  performed  by  NTIA,  the  absence  of  detailed  information  on  receiver  variability  in  the  record,  and  the  conclusions  reached  in  the  JHU/  APL  analysis,  we  are  applying  a  value  of 
 3  dB  in  this  analysis  for  manufacturer  variation. 
 97.  As  part  of  a  separate  measurement  effort,  NTIA  has  conducted  building  attenuation  loss  measurements  at  912,  1920,  and  5990  MHz.  185  The  measurements  were  performed  for  different  buildings 

 representing  typical  residential  and  high-  rise  office  construction.  Based  on  the  results  of  these  measurements,  an  average  building  attenuation  of  9  dB  in  the  range  960-  1610  MHz  in  which  GPS 
 operates  is  used  in  this  analysis.  The  standard  deviation  for  the  measurements,  however,  is  on  the  same  order  of  magnitude  as  the  value  of  building  attenuation  loss.  186 

 98.  The  NTIA  measurements  did  not  consider  the  acquisition  of  a  new  satellite  in  the  presence  of  a  UWB  signal.  The  acquisition  threshold  is  known  to  be  more  sensitive  than  the  tracking 
 threshold,  which  can,  in  part,  be  attributed  to  the  time  and  frequency  search  performed  by  the  GPS  receiver  as  part  of  the  satellite  acquisition  scheme.  As  part  of  the  satellite  acquisition  process,  the  loop 
 filter  bandwidths  are  increased,  which  causes  the  noise  (N)  to  increase  reducing  the  effective  carrier-  to-noise  ratio  (C/  N).  The  acquisition  mode  of  the  GPS  receiver  is  extremely  difficult  to  measure,  because  it 
 is  highly  dependent  on  manufacturer-  specific  acquisition  algorithms.  A  6  dB  factor  is  typically  used  in  GPS  interference  analyses  to  account  for  the  greater  sensitivity  of  satellite  acquisition.  187  This  6  dB 
 reduction  in  the  interfering  signal  power  level  only  provides  protection  of  2.5  dB  in  C/  N+  I,  which  is  a 
 180  Firmware  is  software  installed  in  a  device  that  is  typically  stored  in  read  only  memory  (ROM)  or 
 programmable  read  only  memory  (PROM).  181 
 See  NTIA  Special  Publication  01-  47,  Assessment  of  Compatibility  Between  Ultrawideband  (UWB)  Systems  and  Global  Positioning  System  (GPS)  Receivers  (Report  Addendum),  November  2001.  at  pg.  2-  13. 

 182  TDC  Comments  in  Response  to  Public  Notice  at  pg.  56. 
 183  Id. 
 184  JHU/  APL  Report  at  ES-  2. 
 185  NTIA  Report  95-  325,  Building  Attenuation  Measurements  From  Low-  height  Base  Stations  at  912,  1920, 
 and  5990  MHz,  September  1995,  at  pg.  43.  186 
 Id.  at  pg.  36.  187 
 Understanding  GPS  Principles  and  Applications,  E.  D.  Kaplan  (Editor),  Artech  House,  1996,  pg.  211;  ITU-R  M.  1477  at  Annex  1 
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 critical  factor  in  GPS  receiver  performance.  Since  the  performance  metric  of  break-  lock  is  related  to  the  tracking  performance  of  the  GPS  receiver,  including  the  acquisition  factor  in  the  analysis  when  the 
 interference  susceptibility  is  based  on  the  break-  lock  performance  is  appropriate. 
 99.  The  second  limiting  operational  scenario  to  be  considered  for  UWB  devices  is  the  indoor  use  of  E-  911  GPS  receivers.  Because  buildings  and  other  structures  attenuate  the  received  GPS  satellite 

 signals,  indoor  reception  has  been  not  been  possible  previously.  However,  Global  Locate  and  Snap  Track  (Qualcomm)  have  developed  technologies  that  permit  indoor,  enhanced  GPS  reception  for  E-  911 
 applications.  These  technologies  rely  on  enhancing  the  signal  processing  of  the  E-  911  received  GPS  signal  with  information  provided  from  a  separate  GPS  receiver  located  at  the  base  station.  This 
 supplemental  information  provides  Doppler  and  code  shift  data  to  allow  acquisition  and  tracking  of  low  level  GPS  signals.  In  addition,  information  involving  phase  shifts  caused  by  the  GPS  navigation  signal  is 
 provided  to  allow  coherent  integration  of  the  E-  911  GPS  signal  for  a  period  longer  than  20  milliseconds.  The  enhanced  GPS  receiver  integrates  the  satellite  signal  over  a  longer  time  period,  allowing  the  receiver 
 to  obtain  a  20  to  30  dB  higher  processing  gain  than  a  conventional  GPS  receiver.  188  This  higher  processing  gain  permits  the  reception  of  a  GPS  signal  that  is  significantly  below  the  receiver  noise  floor 
 in  a  1  MHz  bandwidth.  189 
 100.  This  processing,  to  determine  location  of  the  E-  911  receiver,  can  be  carried  out  at  the  E-911  receiver  using  supplemental  data  from  the  base  station  that  is  provided  via  the  phone  connection.  An 

 alternative  is  to  do  the  final  processing  at  the  base  station.  For  example,  a  snapshot  (in  time)  of  the  signals  (in  the  GPS  band)  received  at  the  E-  911  receiver  is  forwarded  to  the  base  station  via  the  phone 
 connection  where  the  signal  and  supplemental  information  is  processed  to  determine  location  of  the  E-  911  receiver.  These  processing  technologies  require  that  the  E-  911  receiver  not  be  on  a  platform  that  is 
 moving  rapidly.  Significant  motion  could,  for  example,  invalidate  the  supplemental  Doppler  information  and/  or  invalidate  the  final  position  solution,  which  involves  some  time  latency  due  to  the  signal 
 processing  procedure.  At  this  time,  it  is  expected  that  the  E-  911  position  determination  would  not  be  invoked  until  the  emergency  (911)  call  is  placed. 

 101.  Regardless  of  the  processing  gain  or  the  bandwidth  of  the  tracking  loop,  the  minimum  level  of  the  GPS  signal  that  can  be  used  for  an  E-  911  position  determination  will  be  determined  by  the 
 receiver  system  noise  density.  An  interfering  signal  that  adds  to  the  system  noise  density  will  necessitate  a  higher  GPS  signal  level  thus  decreasing  the  indoor  coverage  of  the  E-  911  position  determination 
 capability.  Thus,  we  believe  that  an  analysis  of  an  indoor  UWB  transmitter  and  an  E-  911  GPS  receiver  provides  the  more  stringent  interference  example.  The  USGPSIC  provided  an  operational  scenario  for  an 
 E-  911  GPS  receiver.  190  The  following  table  provides  an  overview  of  the  technical  factors  considered  in  the  USGPSIC  analysis  for  this  operational  scenario. 

 188  Note  that  these  are  only  estimates  of  what  values  of  processing  gain  can  be  achieved  and  may  vary 
 depending  on  the  implementation  of  the  technology.  189 
 No  E-  911  receivers  were  available  for  testing  purposes.  The  information  herein  is  based  on  our  meeting  with  Qualcomm  on  9/  26/  01. 

 190  Stephen  D.  Baruch,  Counsel  for  the  U.  S.  GPS  Industry  Council,  Written  Ex  Parte  Presentation  in  ET 
 Docket  No.  98-  153,  June  21,  2001,  at  pg.  11. 
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 Table  2  USGPSIC  Analysis  of  UWB  Indoor  Interference  to  E-  911  Indoor  System 
 Parameter  Value  Receiver  Susceptibility  Mask  (dBm/  MHz) 
 (Broadband  Noise)  -111.5  Public  Safety  Margin  (dB)  -6 
 Multiple  System  Allotment  (Excluding  MSS)  (dB)  -3  Single  Emitter  Allotment  -6 
 GPS  Antenna  Gain  in  Direction  of  RFI  Source  (dBi)  0  Propagation  Loss  (dB) 
 (Minimum  Distance  Separation  (meters))  46  (3)  Noise-  Like  RFI  Emission  Limit  (dBm/  MHz)  -80.5 
 47  C.  F.  R.  15.  209  Emission  Limit  (dBm/  MHz)  -41.3  Additional  Attenuation  Required  (dB)  39.2 

 102.  The  UWB  emission  limit  recommended  in  the  above  table  is  calculated  by  adding  the  values  in  the  columns.  As  shown  in  the  table,  the  USGPSIC  states  that  for  noise-  like  interference,  UWB 
 signals  must  be  39  dB  below  the  47  C.  F.  R.  15.209  emission  limit  to  protect  the  GPS  receiver  under  the  conditions  in  this  operational  scenario.  The  following  paragraphs  will  examine  and  assess  the  viability  of 
 each  of  the  technical  factors  considered  in  this  operational  scenario. 
 103.  The  interference  susceptibility  level  specified  by  the  USGPSIC  is  111.5  dBm/  MHz,  which  is  equal  to  an  interference  density  of  171.5  dBm/  Hz.  The  typical  receiver  system  noise  density  of 

 a  GPS  receiver  is  171.5  dBm/  Hz  for  a  3  dB  receiver  noise  figure.  191  Therefore  the  specified  interference  susceptibility  represents  an  I/  N  of  0  dB  or  a  3  dB  increase  in  the  system  noise  density.  This  means  that 
 interference  at  this  level  can  cause  a  100%  increase  in  the  GPS  receiver  system  noise  density.  As  stated  earlier,  the  receiver  system  noise  density  determines  the  minimum  level  of  the  GPS  signal  that  can  be 
 used  for  an  E-  911  position  determination.  Therefore,  an  interfering  signal  that  adds  to  the  system  noise  density  will  limit  the  GPS  signal  level  that  can  be  tracked  by  the  receiver.  Conventional  GPS  receivers 
 require  a  relatively  high  C/  N0  because  of  the  wide  loop  bandwidths  that  are  employed.  In  contrast  GPS  receivers  used  in  E-  911  applications  can  take  full  advantage  of  communication  network  support  to  obtain 
 and  remove  the  GPS  navigation  data  and  to  stabilize  the  receiver  clock.  In  addition,  it  is  assumed  that  the  dynamics  are  very  low  (e.  g.,  the  user  is  walking).  As  a  result,  the  tracking  bandwidth  can  be  narrowed 
 very  substantially,  thus  maintaining  a  positive  signal-  to-  noise  ratio  in  the  tracking  loop  at  much  lower  C/  N0  values.  Receivers  are  being  designed  today  which  can  track  with  a  20  dB  C/  N0,  and  the  industry  is 
 striving  to  track  with  a  C/  N0  of  10  dB.  Based  on  the  system  noise  density  of  171  dBm/  Hz,  a  20  dB  C/  N0  represents  a  received  signal  level  of  151  dBm,  and  a  10  dB  C/  N0  represents  a  received  signal  level  of   
 161  dBm.  There  are  existing  GPS  receivers  that  are  capable  of  tracking  signals  that  are  21  dB  weaker  than  the  signal  levels  considered  in  the  measurement  efforts  that  are  part  of  the  public  record  in  this 
 proceeding.  If  improvements  permit  tracking  at  a  C/  N0  of  10  dB,  the  tracked  signal  level  would  be  31  dB  weaker  than  the  signal  levels  considered  in  the  measurement  efforts.  Based  on  the  lower  received  signal 
 levels  that  can  be  tracked  by  GPS  receivers,  a  100%  increase  in  the  system  noise  may  not  be  acceptable.  We  are  therefore  limiting  at  this  time  the  increase  in  system  noise  caused  by  noise-  like  UWB  signals  to 
 50%,  which  equates  to  an  I/  N  of  3  dB.  Based  on  the  I/  N  of  3  dB  the  interference  susceptibility  level  used  in  the  analysis  will  be  114.5  dBm/  MHz. 

 104.  ITU-  R  M.  1477  specifies  a  6  dB  safety  margin  to  account  for  uncertainties  on  the  aviation  side  of  the  link  budget  that  are  real  but  not  quantifiable,  which  include  but  are  not  limited  to:  multipath  of 
 the  GPS  signal;  receiver  implementation  losses;  antenna  gain  variations;  and  approach  path  deviation. 
 191  The  noise  figure  of  a  GPS  receiver  typically  is  in  the  range  of  2  to  4  dB. 
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 Since  the  GPS  signal  level  cannot  be  increased,  the  aviation  safety  margin  is  implemented  by  lowering  the  allowable  interference.  In  Annex  5  of  ITU-  R  M.  1477  the  need  for  an  aviation  safety  margin  is 
 justified  by  citing  examples  of  other  aviation  systems  such  as  the  Instrument  Landing  System,  and  the  Microwave  Landing  System  that  both  use  a  safety  margin.  ITU-  R  M.  1477  specifies  a  6  dB  margin  for 
 aviation  safety  of  life  applications  employing  GPS  receivers.  Therefore,  it  is  not  appropriate  to  apply  this  margin  to  non-  aviation  safety  of  life  applications  using  GPS  receivers,  and  the  public  safety  margin  of  6 
 dB  specified  by  the  USGPSIC  should  not  be  used  in  the  E-  911  operational  scenario  analysis. 
 105.  The  USGPSIC  defined  E-  911  GPS  receiver  operational  scenario  includes  a  3  dB  factor  for  multiple  interfering  systems  allotment,  excluding  MSS.  This  factor  is  used  for  the  composite  of  all 

 UWB  and  future  radio  frequency  interference  sources.  The  3  dB  factor  is  equivalent  to  a  50%  interference  allotment  to  UWB  devices.  The  remaining  50%  is  to  account  for  all  other  potential  sources  of 
 interference.  Since  the  GPS  receiver  is  operating  indoors  this  will  minimize  the  potential  for  interference  from  other  sources  such  as  700  MHz  commercial  and  pubic  safety  mobile  and  base  stations  transmitters 
 and  harmonics  from  DTV  stations.  Furthermore,  as  shown  in  the  table  above,  the  minimum  distance  separation  is  3  meters.  For  operational  scenarios  where  the  minimum  distance  separation  between  the 
 GPS  receiver  and  UWB  devices  is  on  the  order  of  several  meters,  the  UWB  device  is  expected  to  be  the  dominant  source  of  interference.  Therefore,  for  the  E-  911  GPS  receiver  operational  scenario  it  is  not 
 appropriate  to  include  a  factor  for  other  sources  of  interference. 
 106.  The  USGPSIC  defined  E-  911  GPS  receiver  operational  scenario  includes  a  factor  for  multiple  UWB  devices.  As  shown  in  the  table  there  is  a  factor  that  accounts  for  4  UWB  devices  causing 

 noise  like  interference  each  operating  at  the  minimum  separation  distance  of  3  meters.  Although  this  minimum  distance  separation  may  be  acceptable  when  assessing  interference  from  a  single  UWB  device, 
 we  believe  that  it  is  not  appropriate  when  assessing  interference  from  multiple  UWB  devices.  Therefore,  for  this  operational  scenario,  it  is  not  appropriate  to  consider  multiple  UWB  devices  operating  at  such  a 
 close  distance.  When  considering  interference  to  GPS  E-  911  receivers  from  a  single  indoor  system,  NTIA  employed  a  minimum  separation  distance  of  2  meters  in  this  analysis.  We  have  employed  the 
 antenna  model  specified  in  the  NTIA  analysis,  using  an  antenna  gain  of  0  dBi  in  the  direction  of  the  UWB  device.  We  also  have  employed  NTIAs  use  of  the  free  space  propagation  model  to  compute  the 
 propagation  loss. 
 107.  The  table  below  shows  the  amount  of  additional  attenuation  below  the  current  47  C.  F.  R.  15.209  emission  limits  that  is  needed  to  protect  an  E-  911  GPS  receiver  under  the  revised 

 conditions. 

 Table  3  Analysis  of  Indoor  E-  911  Using  Revised  Conditions 

 Parameter  Value  Receiver  Susceptibility  Mask  (dBm/  MHz) 
 (Broadband  Noise)  -114.5  GPS  Antenna  Gain  in  Direction  of  RFI  Source  (dBi)  0 
 Propagation  Loss  (dB)  (Minimum  Distance  Separation  (meters))  42.4  (2) 
 Noise-  Like  RFI  Emission  Limit  (dBm/  MHz)  -72.1  47  C.  F.  R.  15.  209  Emission  Limit  (dBm/  MHz)  -41.3 
 Additional  Attenuation  Required  (dB)  30.8 
 108.  As  shown  in  the  table  above,  for  noise-  like  interference,  UWB  signals  should  be  31  dB  below  the  47  C.  F.  R.  15.209  emission  limit  to  protect  the  GPS  receiver  in  this  operational  scenario.  This 
 conclusion  is  based  on  limited  quantitative  information  that  was  inserted  recently  into  the  record  by  NTIA.  Out  of  an  abundance  of  caution  to  protect  the  newly  emerging  GPS-  based  indoor  E-  911  systems 
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 and  their  safety  implications  from  UWB  devices  with  which  we  also  have  minimal  operational  experience,  we  are  basing  our  UWB  rules  on  this  analysis. 
 109.  Qualcomm  submitted  an  ex  parte  presentation  for  the  public  record  reporting  on  a  series  of  test  to  assess  the  impact  of  UWB  emissions  on  the  performance  of  a  GPS  enabled  PCS  phone.  192  This 
 type  of  GPS  receiver  is  designed  to  provide  location  information  for  E-  911  callers  in  compliance  with  our  E-  911  mandate.  The  Qualcomm  measurements  used  a  GPS  signal  level  at  the  input  to  the  receiver  that 
 resulted  in  a  C/  N0  of  34  dB-  Hz.  193  The  noise  figure  of  the  GPS  receiver  was  4  dB.  194  This  results  in  a  receiver  noise  density  level  of  170  dBm/  Hz  (-  110  dBm/  MHz)  and  a  GPS  signal  level  of  -136  dBm  for  a 
 34  dB-  Hz  condition.  Qualcomm  selected  the  34  dB-  Hz  level  as  it  represented  a  value  exceeded  in  5%  of  the  test  cases  for  within  building  applications.  195  The  UWB  signal  was  then  input  to  the  GPS  receiver  and 
 the  location  accuracy  determined  as  a  function  of  UWB  signal  level.  For  dithered  (noise-  like)  UWB  signals  the  50  th  percentile  position  accuracy  increased  to  50  m  at  -97.5  dBm/  2  MHz  or  -100.5dBm/  MHz. 
 This  interference  level  is  9.5dB  above  receiver  noise  (I/  N  =  9.5dB).  However,  our  requirement  for  E-  911  performance  includes  a  specification  for  95%  of  the  calls.  Using  the  Qualcomm  cumulative  distribution 
 plots  for  C/  N0,  a  value  that  would  be  exceeded  in  95%  of  the  cases  can  be  determined.  196  This  value  is  22.5  dB-  Hz  and  is  11.5  dB  below  the  value  for  5%  of  the  cases.  That  is  the  carrier  (GPS  signal)  is  11.5 
 dB  weaker.  GPS  performance  is  related  to  the  carrier-  to-  interference  ratio  so  that  an  11.5  dB  decrease  in  carrier  level  should  result  in  a  requirement  to  lower  the  UWB  interference  level  by  approximately  11.  5  dB 
 to  maintain  the  required  position  accuracy.  Relating  this  to  the  measured  I/  N  of  9.5dB  would  indicate  an  I/  N  of  -2dB  would  be  required  for  95  th  percentile  C/  N0  level. 

 110.  Similarly,  the  Qualcomm  test  effort  evaluated  UWB  signals  with  a  constant  PRF  resulting  in  a  UWB  spectrum  with  CW  lines.  As  previously  discussed  in  paragraph  82,  supra,  GPS  can 
 be  more  susceptible  to  CW-  like  interference  than  to  noise-  like  interference.  The  Qualcomm  test  results  showing  50  th  percentile  position  errors  for  noise-  like  and  CW-  like  interference  cases  show  very  similar 
 position  error  versus  UWB  power  level  performance  characteristics.  This  could  be  interpreted  that  there  was  no  difference  in  susceptibility  for  noise-  like  and  CW-  like  interference.  This  could  be  explained  by 
 considering  the  accuracy  performance  is  a  50  th  percentile  value  and  one  would  not  expect  the  alignment  of  GPS  and  interference  spectral  lines  to  occur  in  a  significant  number  of  cases  considering  the  narrow  loop 
 bandwidths  used  in  the  E-  911  GPS  receivers  and  the  fairly  short  length  of  time  to  determine  position.  A  few  instances  of  CW  line  alignment  would  not  seriously  impact  the  50  th  percentile  position  error.  As 
 shown  in  the  test  report  an  800-  meter  position  error  was  used  as  a  default  value  when  there  is  not  sufficient  information  to  obtain  a  position  measurement  197  .  Examination  of  the  UWB  impact  versus  time 
 information  shows  5  cases  of  800-  meter  errors  in  approximately  50  calls.  198  Some  of  these  800-  meter  errors  could  have  been  caused  by  CW-  like  interference,  which  is  expected  to  be  a  low  probability  event 
 for  E-  911  service.  In  addition  some  E-  911  GPS  receivers  are  reportedly  using  processing  techniques  that  in  effect  converts  CW  energy  into  broadband  interference.  It  is  not  known  whether  the  Qualcomm 
 receiver  includes  such  processing.  We  believe,  therefore,  that  the  Qualcomm  test  data  is  inconclusive  in  the  area  of  increased  susceptibility  of  the  GPS  receiver  tested  to  CW-  like  interference  as  compared  to 

 192  Written  Ex  Parte  Presentation,  ET  Docket  98-  153,  Revisions  of  Part  15  of  The  Commissions  Rules 
 Regarding  Ultra-  Wideband  Transmission  Systems  (January  11,  2002)  193 

 Id  at  pg.  12.  194 
 Id  at  Fig  4-  19  195 
 Id  at  Fig  3-  6  196 
 Id  197 
 Id  at  pg.  14  198 
 Id  at  Fig  4-  1 
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 noise-  like  interference. 
 111.  Based  on  the  above  analysis,  of  the  two  limiting  operational  scenarios  for  the  indoor  use  of  UWB  devices,  a  UWB  signal  level  31  dB  below  the  Part  15  general  emission  limits  would  be  required 

 for  noise-  like  UWB  emissions  in  the  960-  1610  MHz  range.  Based  on  the  various  uncertainties  at  this  time  and  the  lack  of  operational  experience  with  UWB  systems,  we  believe  that  an  additional  attenuation 
 of  3  dB  is  reasonable  giving  a  total  attenuation  of  34  dB  below  the  15.209  emission  limit.  This  attenuation  will  be  required  for  all  indoor  and  outdoor  non-  imaging  UWB  systems,  including  vehicular 
 radars  and  hand  held  systems. 
 112.  We  are  permitting  imaging  systems,  vehicular  radar  systems  and  hand  held  devices  to  operate  outdoors,  at  any  PRF  provided  the  emissions  in  the  GPS  bands  are  below  the  Part  15  general 

 emission  limit.  The  limiting  operational  scenario  considered  for  the  outdoor  use  of  GPS  and  imaging  systems  is  given  in  the  table  below. 

 Table  4  Outdoor  Analysis  for  Imaging  System  Interference  to  GPS 
 Parameter  Value  GPS  Receiver  Interference  Susceptibility 
 (dBm/  MHz)  (Broadband  Noise)  -114.5 
 Propagation  Loss  (dB)  (Minimum  Distance  Separation  (m))  49.5  (4.5  m) 
 GPS  Receive  Antenna  Gain  (dBi)  0  Maximum  Allowable  EIRP  (dBm/  MHz)  -65 
 47  C.  F.  R.  15.  209  Emission  Limit  (dBm/  MHz)  -41.3  Additional  Attenuation  Required  (dB)  23.7 

 113.  As  shown  in  the  table  above,  a  signal  level  24  dB  below  the  Part  15  general  emission  limit  is  required  for  noise-  like  emissions  in  the  960-  1610  MHz  frequency  range  from  imaging  systems 
 under  the  conservative  assumptions  we  are  using  based  on  the  record.  We  also  believe  that  imaging  systems  typically  will  emit  RF  energy  only  for  short  periods  of  time,  so  any  possible  interference  from 
 operation  at  closer  distance  separations  should  be  transient. 
 114.  In  limited  cases  involving  public  safety  uses  of  UWB  imaging  where  there  are  positive  public  safety  benefits  from  the  UWB  use  and  where  coordination  can  be  used  to  limit  the  risk  of 

 interference  to  safety-  related  uses  of  GPS,  we  believe  that  12  dB  less  attenuation,  resulting  in  an  emission  level  12  dB  below  the  15.209  emission  limit,  represents  the  appropriate  balancing  of  public  interests. 

 115.  The  limiting  operational  scenario  considered  for  the  outdoor  use  of  GPS  and  vehicular  radar  systems  is  given  in  the  table  below. 

 Table  5  Analysis  for  Vehicular  Radar  System  Interference  to  GPS  Receivers 
 Parameter  Value  Receiver  Susceptibility  Mask  (dBm/  MHz) 
 (Broadband  Noise)  -114.5  GPS  Antenna  Gain  in  the  Direction  of 
 UWB  Device  (dBi)  4.5  Propagation  Loss  (dB)  45.9 
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 (Minimum  Distance  Separation  (meters))  (3)  Allotment  for  Multiple  UWB  devices  (dB)  -7.8 
 Noise-  Like  Emission  Limit  (dBm/  MHz)  -71.9  47  C.  F.  R.    15.209  Emission  Limit 
 (dBm/  MHz)  -41.3  Additional  Attenuation  Required  (dB)  30.6 

 116.  The  typical  implementation  of  the  vehicular  radar  systems  will  consist  of  multiple  radar  systems  (as  many  as  12  per  vehicle)  that  are  mounted  on  the  bumpers  and  fenders  of  the  vehicle. 
 Vehicular  radar  systems  will  also  employ  directional  antennas  and  will  be  installed  at  a  height  of  approximately  0.5  meters.  199  Based  on  anticipated  operational  use  of  vehicular  radar  systems  the  antenna 
 discrimination  of  a  GPS  antenna  in  the  direction  of  the  vehicular  radar  systems  and  interference  from  multiple  vehicular  radar  systems  must  be  considered  in  the  analysis. 

 117.  Since  the  vehicular  radar  systems  are  mounted  at  a  height  of  approximately  0.5  meters  they  will  typically  be  below  the  GPS  antenna.  Based  on  the  antenna  model  provided  by  NTIA,  the  GPS 
 receive  antenna  gain  in  the  direction  of  the  vehicular  radar  systems  would  be  4.5  dBi.  In  order  to  determine  the  location  of  vehicles  and  objects  that  surround  the  vehicle  multiple  vehicular  radar  systems 
 employing  directional  antennas  will  be  employed.  In  this  analysis  it  will  be  assumed  that  there  are  six  vehicular  radar  systems  transmitting  in  the  direction  of  the  GPS  receiver  and  a  factor  of  10  Log  (6)  or  7.8 
 dB  will  be  included  in  the  analysis. 
 118.  The  calculations  shown  in  Table  5  lead  to  a  conclusion  that  a  signal  level  31  dB  below  the  Part  15  general  emission  limit  is  required  for  noise-  like  emissions  from  vehicular  radar  systems  in  the 

 960-  1610  MHz  frequency  range  based  on  the  conservative  assumptions  and  limited  record  on  operational  experience  that  we  are  using  at  this  time.  Because  of  the  present  uncertainties  in  predicting  interference 
 from  UWB  devices  for  which  we  have  no  operational  experience  and  our  concern  about  certain  safety-related  applications  of  GPS,  we  agree  to  employ  the  additional  safety  margin  applied  by  NTIA  to  the 
 receiver  susceptibility  mask,  resulting  in  an  emission  level  34  dB  below  the  Part  15  limits. 
 119.  The  previous  discussion  has  focused  on  interference  from  noise-  like  UWB  emissions  to  GPS.  UWB  emissions  can  also  have  discrete  spectral  lines  or  CW-  like  emissions  in  addition  to  noise-  like 

 emissions  depending  on  the  statistical  details  of  time  spacing  between  adjacent  pulses.  200  Now  will  we  consider  limits  on  these  CW-  like  emissions. 

 120.  The  measured  level  at  which  interference  occurred  to  the  GPS  C/  A  code  receiver  was  8  dB  less  for  a  CW-  like  UWB  signal  than  for  the  noise-  like  UWB  signal.  As  also  indicated,  this  measured 
 difference  is  in  agreement  with  the  RTCA  and  ITU-  R  standards,  which  specify  a  10  dB  difference  for  the  two  interference  effects.  Accordingly,  we  agree  that  UWB  emissions  appearing  within  the  960-  1610 
 MHz  frequency  range  due  to  narrowband  CW-  like  interference  signals  should  be  10  dB  below  the  emission  power  level  measured  in  a  1  MHz  bandwidth  permitted  for  noise-  like  emissions.  As  discussed 
 in  the  section  addressing  emission  limits,  we  are  implementing  this  by  requiring  that  the  UWB  transmitters  be  demonstrated  to  comply  with  this  limit  when  measured  with  a  spectrum  analyzer 

 199  BOSCH  presentation  to  European  Ultra  Wideband  Workshop,  Short  Range  Automotive  Radar  (SRR)   
 another  generic  (ultra)  wide  band  device  at  24  GHz  (March  20,  2001)  at.  pg.  4.  200 
 In  theory  these  spectral  lines  could  be  eliminated,  the  requirement  in  practical  systems  to  have  a  lower  bound  on  the  time  between  pulses  leads  to  structure  in  the  signals  autocorrelation  function  and  therefore  spectral 

 lines  of  some  magnitude. 
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 employing  a  resolution  bandwidth  no  less  than  1  kHz.  201  The  above  requirements  for  UWB  emission  levels  appearing  in  the  960-  1610  MHz  frequency  range  also  will  be  satisfactory  for  GPS  receivers  that 
 work  with  satellite-  based  augmentation  systems  (SBAS)  and  ground  based  augmentation  systems  (GBAS).  ITU-  R  Recommendation  M.  1477  provides  receiver  specifications  for  an  SBAS  air  navigation 
 receiver  to  be  used  in  Category  I  precision  approach  operations  and  a  GBAS  air  navigation  receiver  to  be  used  with  Category  II/  III  precision  approach  operations.  In  both  instances,  the  minimum  required  power 
 level  at  the  input  is  specified  at  131  dBm,  only  one  dB  lower  than  the  specification  for  the  C/  A  code  GPS  receiver.  In  both  cases,  the  specified  receiver  aggregate  wideband  interference  threshold  in  track 
 and  acquisition  mode  is  identical  to  the  RTCA  and  ITU-  R  thresholds  for  the  C/  A  code  GPS  receiver.  Hence,  the  conclusions  above  will  apply  to  SBAS  or  GBAS  and  GPS  receivers. 

 121.  The  semi-  codeless  GPS  receivers  have  more  stringent  requirements  on  GPS  received  signal  levels  (3  dB  lower)  than  the  C/  A  code  GPS  receivers,  and  the  wideband  interference  requirements 
 for  tracking  mode  is  6  dB  lower  than  the  C/  A  code  GPS  receiver.  202  The  wideband  interference  requirement  for  acquisition  is  the  same  for  both  classes  of  receiver.  Because  the  semi-  codeless  receiver 
 works  with  the  GPS  P-  signal,  which  has  essentially  no  spectral  line  content,  this  receiver  is  not  sensitive  to  the  spectral  lines  in  the  CW-  type  UWB  emissions,  as  demonstrated  by  NTIAs  measurements  for  the 
 C/  A  code  receiver  architecture.  NTIAs  measurements  also  demonstrated  the  same  robust  operations  for  low  PRF  signals  as  the  C/  A  code  receiver.  The  NTIA  measurements  supported  an  increased  sensitivity  to 
 noise-  like  UWB  emissions  than  for  the  C/  A  code  receiver  architecture.  Nevertheless,  the  operational  scenarios  examined  by  NTIA  involving  surveying  applications  that  employ  the  semi-  codeless  architecture 
 receiver  produced  interference  levels  that  were  higher  than  the  terrestrial  operational  scenarios.  In  any  case,  since  the  semi-  codeless  receiver  relies  on  the  C/  A  code  for  initial  acquisition  and  it  typically 
 defaults  to  C/  A  code  operation  if  the  P-  signal  becomes  unavailable  the  C/  A  code  receiver  performance  drives  the  UWB  threshold  limits  for  all  receiver  types  discussed  earlier. 

 2.  NTIA  Analyses  of  Interference  to  Various  U.  S.  Government  Systems: 
 122.  NTIA  analyzed  the  interactions  between  UWB  transmitters  and  a  number  of  U.  S.  Government  radio  communication  systems  to  determine,  inter  alia,  the  maximum  UWB  emission  levels 

 that  could  be  allowed  without  causing  interference.  These  analyses  were  based  on  an  extensive  laboratory  measurement  program  at  the  Institute  for  Telecommunication  Sciences,  in  Boulder,  CO.  The 
 measurement  program  identified  various  methods  being  currently  used  to  generate  UWB  signals  and  characterized  the  essential  parameters  of  UWB  systems  provided  by  various  UWB  manufacturers.  The 
 ITS  verified  how  filters  of  varying  bandwidths  respond  to  numerous  types  of  UWB  signals  and  determined  measurement  techniques  that  correctly  measure  the  emission  spectra  of  UWB  devices.  The 
 ITS  also  performed  a  measurement  program  to  determine  the  nature  of  the  aggregation  of  UWB  signals.  203  NTIA  also  initiated  a  measurement  program  consisting  of  field  measurements  of  radiated 
 UWB  signals  at  the  FAA  Aeronautical  Center  in  Oklahoma  City,  OK  to  determine  the  effects  of  one  UWB  device  operating  at  the  current  Part  15  limits  on  Air  Route  Surveillance  Radars  (ARSR),  and 
 Airport  Surveillance  Radars  (ASR)  in  order  to  validate  the  prediction  models  used  in  the  analysis.  In  its  reports,  NTIA  provided  quantitative  values  for  UWB  emission  limits  involving  federal  systems  for  the 
 following:  RMS  power  limits  for  a  UWB  device  located  at  2  m  and  at  30  m  above  the  ground  for  15  systems  (and  peak  power  limits  for  two  of  the  systems);  and  developed  a  computer  model  for  assessing 
 the  impact  of  aggregate  UWB  interference.  The  NTIA  interference  analyses  of  the  effects  of  RMS  and  peak  power  were  based  on  a  link  budget  equation  involving  the  system  threshold  for  interference,  as 

 201  This  is  similar  to  an  approach  we  have  used  to  protect  GPS  from  Mobile  Satellite  System  (MSS)  out-  of-band 
 emissions.  See  47  C.  F.  R.  25.  ____  202 
 ITU-  R  M1477  at  Annex  1  Table  3.  203 
 See  NTIA  Special  Publication  01-  43,  supra,  and  NTIA  Report  01-  384,  supra. 
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 determined  using  standard  established  interference  protection  criteria,  actual  antenna  elevation  gain  patterns  for  the  victim  receivers,  the  smooth  earth  option  of  the  Irregular  Terrain  Model  for  propagation 
 loss,  estimated  system  losses,  and  the  empirically  determined  correction  factors  for  bandwidth  to  determine  the  UWB  limits  in  power  per  megahertz  (dBm/  MHz). 

 123.  The  NTIA  analysis  was  performed  for  7  UWB  PRFs  ranging  from  1  kHz  to  500  MHz  for  both  dithered  and  undithered  signals.  The  NTIA  study  used  the  current  Part  15  limit,  an  RMS  EIRP  of 
 -41.3  dBm/  MHz  at  frequencies  above  1  GHz,  as  the  baseline  for  the  study.  The  study  determined  the  allowable  UWB  emission  levels  and  did  not  specifically  address  the  12  dB  reduction  from  the  current  Part 
 15  level  in  the  bands  below  2  GHz  as  proposed  in  the  Notice.  The  analysis  also  assumed  that  the  UWB  devices  were  located  out  of  doors.  The  following  is  a  summary  of  NTIAs  report.  A  more  detailed 
 analysis  has  been  placed  in  the  docket  file  for  this  proceeding. 

 Table  6  Maximum  UWB  EIRP  for  Outdoor  Use  of  UWB  at  2m  &  30  m 

 System  Frequency  (MHz) 
 Maximum  UWB  EIRP 
 (dBm/  MHz)  UWB 
 Outdoors  2  m  height 

 Maximum  UWB  EIRP 
 (dBm/  MHz)  UWB 
 Outdoors  30  m  height 
 DME,  Interrogator  960-  1215  -47  Not  Applicable  DME,  Transponder  1025-  1150  -64  -57 
 ATCRBS,  Transponder  1030  -44  Not  Applicable 
 ATCRBS,  Interrogator  1090  -31  -45 
 ARSR-  4  1240-  1370  -61  -82  SARSAT  1544-  1545  -69  -66 
 ASR-  9  2700-  2900  -46  -66  NEXRAD  2700-  2900  -42  -76 
 Marine  Radar  2900-  3100  -56  -57  FSS,  20  degrees  3700-  4200  -36  -42 
 FSS,  5  degrees  3700-  4200  -51  -77  CW  Altimeters  4200-  4400  25  Not  Applicable 
 Pulsed  Altimeter  4200-  4400  14  Not  Applicable  MLS  5030-  5091  -54  Not  Applicable 
 TDWR  5600-  5650  -35  -63 

 124.  NTIA  investigated  the  potential  interactions  of  proposed  UWB  systems  on  15  U.  S.  Government  systems  operating  between  the  frequencies  of  960  and  5650  MHz.  The  systems  investigated 
 included  Distance  Measuring  Equipment  (DME)  interrogator  airborne  receiver,  DME  ground  transponder  receiver,  Air  Traffic  Control  Radio  Beacon  System  (ATCRBS)  air  transponder  receiver,  ATCRBS  ground 
 interrogator  receiver,  ARSR),  Search  and  Rescue  Satellite  (SARSAT)  ground  station  land  user  terminal,  ASR,  Next  Generation  Weather  Radar  (NEXRAD),  Maritime  Radar,  Fixed  Satellite  Service  (FSS)  earth 
 stations,  CW  and  Pulsed  Radar  Altimeters,  Microwave  Landing  Systems  (MLS),  and  Terminal  Doppler  Weather  Radar  (TDWR).  Table  6  denotes  these  systems  and  their  frequency  band  of  operation  and 
 summarizes  NTIAs  conclusions  of  emission  limits  necessary  to  preclude  interference  from  a  UWB  transmitter  operating  at  a  height  of  2  or  30  meters.  The  maximum  UWB  EIRP  is  the  maximum  signal 
 level  that  NTIA  calculated  at  which  a  UWB  transmitter  could  operate  without  causing  interference  to  the 
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 system  when  the  UWB  is  allowed  unrestricted  outdoor  operation  independent  of  the  UWBs  pulsewidth,  PRF,  or  other  modulation  schemes  or  the  nature  of  its  intended  operation  (e.  g.  radio  determination  or 
 communication).  Where  there  was  a  difference  due  to  the  PRF  of  the  UWB  emission,  we  have  included  the  results  from  the  PRF  that  required  the  UWB  emissions  to  be  reduced  to  the  lowest  level.  In  the 
 column  for  30  meters,  Not  Applicable  indicates  that  the  particular  scenario  would  involve  a  UWB  transmitter  on  a  fixed  antenna  tower  at  the  same  altitude  as  the  airborne  victim,  which  would  not  be 
 likely. 
 125.  The  NTIA  protection  criteria  for  most  of  the  systems  were  determined  from  International  Civil  Aeronautical  Organization  (ICAO),  RTCA  and  ITU-  R  standards  developed  from  system  spectrum 

 sharing  criteria.  The  protection  levels  for  the  DME  interrogator,  the  ATCRBS  systems,  and  the  MLS  were  based,  however,  on  specific  system  performance  specifications  and  on  additional  protection  margins 
 recommended  by  the  FAAs  Spectrum  Management  and  Policy  Program  Division.  NTIA  chose  to  use  international  and  national  sharing  and  coordination  criteria  partly  because  harmful  interference  is  a 
 subjective  criterion.  Moreover,  these  are  well-  established  critical  operations,  many  involving  safety  of  life  situations.  Therefore,  NTIA  believes  that  it  is  appropriate  to  provide  them  protection  from 
 interference  rather  than  ensuring  that  harmful  interference  is  unlikely.  We  recognize  that  there  is  usually  more  than  one  valid  approach  to  interference  analysis.  In  several  of  the  analyses  discussed  below,  we 
 present  a  short  discussion  of  the  rationale  for  less  conservative  values  also  identified  in  the  record.  However,  out  of  an  abundance  of  caution,  we  have  deferred  to  NTIAs  experience  with  these  systems  and 
 used  NTIAs  conservative  analyses  to  develop  the  requirements  for  UWB  operations.  The  following  discussion  examines  these  protection  criteria  for  each  of  the  examined  systems. 

 126.  DME,  Interrogator.  This  system  is  used  to  provide  civil  and  military  aircraft  pilots  with  the  distance  from  a  specific  ground  beacon,  the  transponder,  for  navigational  purposes.  In  Appendix  A  of 
 its  report,  NTIA  referenced  the  RTCA  specification  204  for  a  70  percent  reply  efficiency  at  a  83  dBm  receiver  sensitivity,  and  calculated  that  the  interference  threshold  should  be  set  at  115  dBm,  which  is  an 
 I/  N  of  -7  dB  as  shown  by  Table  A-  9.  205  NTIA  concluded  that  for  all  conditions  studied  and  proposed,  a  UWB  EIRP  of  47  dBm  is  adequate  to  protect  the  operations  of  the  DME  interrogator  receiver. 

 127.  Our  evaluation  of  the  NTIA  approach  used  the  99  dBm  RTCA  protection  criterion  but  found  no  basis  for  including  the  additional  16  dB  of  safety  margin  suggested  by  NTIA.  NTIA  indicates 
 they  applied  a  partitioning  of  total  interference  allowing  10  percent  for  UWB  (a  -10  dB  factor)  and  6  dB  for  an  aeronautical  safety  margin  directly  to  the  -99  dBm  RTCA  protection  criterion  calculating  that  the 
 interference  threshold  should  be  -115  dBm.  Employing  a  -99  dBm  protection  criterion  appears  to  be  consistent  with  NTIAs  analysis  of  the  ATCRBS  systems  where  a  very  similar  set  of  operational 
 conditions  applies,  and  where  we  agree  with  the  NTIA  methodology.  We  concluded  that  this  system  would  not  experience  interference  from  a  UWB  device  operating  at  the  Part  15  general  emission  level. 

 128.  DME,  Transponder.  This  device  responds  to  interrogations  from  the  DME  airborne  component.  NTIA  applied  a  10  dB  UWB  partitioning  and  6  dB  aeronautical  safety  margin  directly  to  the 
 106  dBm  receiver  thermal  noise  level  calculating  that  the  interference  threshold  should  be  122  dBm.  The  NTIA  initial  study  of  the  DME  transponder  showed  that  an  EIRP  of  64  dBm  was  necessary  to 
 protect  its  operations  from  UWB  emissions  with  the  additional  caveat  that  no  UWB  could  come  as  close  as  15  meters.  NTIAs  analysis  also  showed  that  an  EIRP  of  41.3  dBm  would  be  adequate  to  protect  the 
 transponder;  however,  it  would  be  necessary  to  ensure  that  UWB  devices  not  operate  any  closer  than  260  meters,  which  cannot  be  guaranteed.  The  operational  limits  required  for  the  protection  of  the  GPS  will 

 204  Minimum  Operational  Performance  Standards  for  Airborne  Distance  Measuring  Equipment  (DME) 
 Operating  within  the  Radio  Frequency  Range  of  960-  1215  MHz,  RTCA  DO-  189,  at  2.  2.  11  (September  1985).  205 
 NTIA  Special  Publication  01-  43,  supra,  at  page  A-  19,  Table  A-  9. 
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 also  be  adequate  to  protect  DME  operations. 
 129.  We  question  the  applicability  of  the  10  dB  value  NTIA  applied  for  UWB  partitioning.  However,  applying  NTIAs  16  dB  protection  criterion  directly  against  the  94  dBm  receiver  sensitivity, 

 similar  to  the  analysis  applied  to  the  DME  interrogator,  resulted  in  an  interference  criterion  of  110  dBm,  which  is  4  dB  below  the  receiver  thermal  noise  floor.  We  concluded  that  a  UWB  EIRP  of  52  dBm 
 provides  an  adequate  protection  threshold  for  the  DME  interrogator  receiver  and  that  the  260-  m  separation  distance  determined  by  NTIA  was  a  conservative  value.  We  note  that  the  protection  criterion 
 employed  by  NTIA  for  this  system  was  based  on  a  CW-  type  interfering  signal  level.  Thus,  we  believe  that  NTIAs  analysis  results  in  a  conservative  protection  value  since  UWB  emissions  are  designed  to  be 
 predominantly  noise-  like.  We  agree  with  NTIA  that  the  operational  limits  for  GPS  protection  will  protect  DME  operations. 

 130.  ATCRBS  Transponder  and  Interrogator.  These  systems  are  used  in  conjunction  with  the  ASR  and  ARSR  and  other  air  traffic  control  radars  to  provide  controllers  with  the  location,  altitude,  and 
 identity  of  civil  and  military  aircraft  through  an  interrogate  and  reply  operation.  The  protection  criteria  employed  by  NTIA  were  based  on  the  minimum  triggering  levels,  that  is  the  minimum  input  power  levels 
 supplied  to  the  sensor  RF  port  that  results  in  a  90  percent  reply  ratio  for  the  transponder,  -77  dBm,  and  a  90  percent  reply  ratio  for  the  interrogator,  -79  dBm.  Both  the  interrogator  and  the  transponder  must  be 
 able  to  demodulate  and  decode  90  percent  of  the  interrogations  (replies)  with  a  S/  I  of  12  dB.  206  NTIA  used  the  power  level  for  90  percent  reply  detection  as  the  system  threshold  and  applied  the  RTCA  and 
 FAA  12  dB  S/  I  criterion  to  these  values  to  determine  the  interference  thresholds.  NTIAs  final  system  interference  thresholds  are  11  dB  above  the  receiver  thermal  noise  floor  for  the  interrogator  system  and  9 
 dB  above  the  receiver  noise  floor  for  the  transponder  system.  We  agree  with  the  NTIA  analysis  and  note  that  ATCRBS  transponder  and  interrogator  operations  will  be  protected  from  harmful  interference  at  the 
 emission  limits  being  established  to  protect  to  other  nearby  systems  (e.  g.,  ARSR-  4,  and  GPS). 
 131.  ARSR-  4.  This  system  is  used  by  the  FAA  and  DOD  to  monitor  aircraft  during  enroute  flight  to  distances  of  beyond  465  km  (250  nautical  miles).  NTIA  used  a  protection  criterion  of  an 

 interference-  to-  thermal  noise  ratio  of  -10  dB,  i.  e.,  I/  N  =  -10  dB,  while  the  current  protection  criteria  in  ITU-  R  Recommendation  M.  1463  is  for  an  I/  N  of  6  dB  for  both  radionavigation  and  radiolocation 
 applications  of  radar.  207  NTIA  calculated  that  low  PRF  operations  of  UWB  devices,  even  near  ground  level,  must  be  limited  to  -60  dBm  EIRP  to  protect  the  ARSR-  4.  We  note  that  the  emission  limits  being 
 required  for  emissions  in  the  GPS  bands  are  adequate  to  protect  ARSR-  4  operations. 
 132.  We  noted  in  our  analysis  that  the  ITU-  R  rationale  for  I/  N  =  -6  dB  relates  to  the  desensitization  of  the  radar  receiver  for  noise-  type  interference  due  to  the  increases  in  the  apparent  noise 

 floor  that  the  receiver  perceives.  This  desensitization  effect  results  in  a  decrease  of  the  maximum  working  range  of  the  radar  (about  6  %)  for  the  smallest  cross  section  target  that  the  radar  can  detect.  The 
 effect  occurs  only  at  the  distance  where  the  signal  to  noise  (S/  N)  of  the  radar  is  marginal  for  normal  performance,  which  is  at  the  boundaries  of  an  azimuthal  angular  section  of  about  half  the  azimuthal  beam 
 width  in  the  direction  of  the  UWB  source.  We  also  noted  that  radar  range  decreases  by  much  larger  amounts  due  to  atmospheric  effects  such  as  rain.  We  believe  that  the  specific  events  that  could  cause  this 
 effect,  such  as  UWB  device  location  and  antenna  orientation  with  respect  to  the  radar,  and  the  relatively 
 206  Minimum  Operational  Performance  Standards  for  Air  Traffic  Control  Radar  Beacon  System/  Mode  Select 
 (ATCRBS/  MODE  S)  Airborne  Equipment,  Radio  Technical  Commission  for  Aeronautics,  RTCA  DO-  181A,  at  2.2.8.1  (January  1992)  and  Federal  Aviation  Administration,  US  Department  of  Transportation,  Specification  for 

 Mode  Select  Beacon  System  (Modes)  Sensor,  Amendment  2,  FAA-  E-  2716  (March  1993).  207 
 An  I/  N  of  6  dB  translates  to  an  increase  in  the  noise  floor  of  1  dB  and  a  reduction  in  the  maximum  radar  range  of  just  under  6  percent.  A  value  of  10  dB  translates  to  an  increase  in  the  noise  floor  of  about  0.5  dB  and  a 

 reduction  in  the  maximum  radar  range  of  just  under  3  percent 
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 mild  nature  of  this  effect  greatly  reduce  the  risk  of  interference.  We  further  note  that  the  NTIA  analysis  did  not  include  an  effect  due  to  the  scanning  beam  of  the  operating  radar.  TDC  stated  that  because  the 
 antennas  main  lobe  is  actually  tapered,  the  response  signals  being  integrated  could  not  have  the  UWB  transmitter  fixed  at  the  maximum  of  the  lobe;  instead,  it  appears  smeared  over  the  beamwidth  of  the 
 antenna.  208  TDC  also  stated  that  beam  shape  losses  raise  the  level  of  the  noise  in  a  typical  radar  receiver  by  at  least  1.6  dB  above  the  thermal  noise  floor  and  possibly  as  high  as  3  dB.  209  We  concluded  that  the 
 potential  for  UWB  interference  to  the  ARSR-  4  was  more  limited  than  the  NTIA  analysis  suggests.  However,  a  more  detailed  analysis  would  involve  statistical  estimates  and  require  information  specific  to 
 individual  radar  sites.  Therefore,  we  deferred  to  the  NTIA  analysis  values  for  this  system.  These  remarks  also  apply  to  the  ASR-  9  and  the  Marine  radar. 

 133.  SARSAT-  LUT.  This  system  provides  distress  alert  and  location  information  to  appropriate  public  safety  rescue  authorities  for  maritime,  aviation,  and  land  users  in  distress.  NTIA  used  a  protection 
 criterion  of  I/  N  =  -9  dB.  The  NTIA  SARSAT-  LUT  analysis  was  based  on  the  SARSAT  receive  antenna  operating  at  an  elevation  angle  of  0  degrees,  i.  e.,  the  receive  antenna  is  pointed  directly  at  the  horizon.  At 
 this  elevation  angle,  the  large  gain  of  the  antenna  amplifies  emissions  from  a  UWB  device  at  2  m  height.  TDC  and  XSI  correctly  noted  that  the  performance  specification  for  SARSAT  dictates  acquiring  the 
 satellite  when  it  reaches  an  elevation  angle  of  5  above  the  horizon  where  there  is  10  dB  less  gain  provided  by  the  SARSAT-  LUT  antenna  than  at  0.  210  However,  the  acquisition  process  begins  at,  or  near 
 0  elevation.  The  SARSAT-  LUT  antenna  is  scanned  to  a  lower  elevation  angle  to  permit  faster  acquisition  of  the  COSPAS/  SARSAT  satellites  as  they  appear  above  the  horizon.  Thus  NTIA  concluded  that  use  of 
 the  maximum  antenna  gain  is  appropriate.  Of  the  UWB  operations  proposed,  outdoors  use  will  have  the  greatest  potential  to  interfere  with  SARSAT  operations. 

 134.  Our  analysis  of  the  SARSAT  noted  that  the  NTIA  protection  criterion  was  not  referenced  from  a  specific  standard  or  recognized  criteria.  SARSAT  is  a  digital  communications  system,  and  we  do 
 not  consider  it  necessary  to  protect  communications  systems  from  signals  that  are  below  the  noise  floor.  These  systems  operate  at  some  margin  above  the  noise  floor  to  account  for  aging  components,  adverse 
 propagation  conditions,  and  other  system  degradations.  Hence,  we  used  the  noise  floor  as  the  protection  level,  i.  e.,  an  I/  N  of  0  dB.  We  also  used  the  angle  of  5  above  the  horizon  based  on  the  SARSAT 
 specification.  We  concluded  that  a  UWB  EIRP  of  50  dBm  was  an  adequate  protection  threshold  for  the  SARSAT  system  for  UWB  emissions  at  a  height  of  2m.  Further,  we  noted  that  the  NTIA  analysis  values 
 are  critically  dependent  on  the  height  of  the  SARSAT  antenna  used  in  the  analysis  (NTIA  used  an  average  height).  Since  there  are  only  7  SARSAT  systems  mostly  located  on  Government  installations,  we 
 believed  that  each  system  could  have  been  addressed  individually  and  that  this  approach  would  have  shown  that  UWB  operations  would  not  cause  interference  to  SARSAT  operations. 

 135.  ASR-  9.  This  radar  monitors  the  location  of  civil  and  military  aircraft  in  and  around  airports  to  a  range  of  110  km  (60  nautical  miles).  NTIA  stated  that  the  protection  criterion  for  this  radar 
 was  an  I/  N  of  10  dB.  The  U.  S.  Submission  to  ITU-  R  Working  Party  8B  proposed  this  level  in  a  revision  to  ITU-  R  M.  1464,  which  is  under  consideration  by  ITU-  R  Study  Group  8  and  is  an  official  US  position. 
 There  is  also  a  proposal  by  Working  Party  8B  to  decrease  the  I/  N  to  12  dB  involving  an  evaluation  of 

 208  TDC  comments  of  February  23,  2001,  at  pg.  26-  27.  Also,  Skolnik,  M.  I.,  Introduction  to  Radar  Systems, 
 (1980)  at  pg.  58-  59.  209 
 We  believe  that  TDC  means  that  the  intensity  of  the  received  signal  is  reduced  by  1.6  to  3  dB  due  to  beam  smearing. 

 210  TDC  comments  of  3/  12/  01  at  pg.  10,  footnote  18.  XSI  comments  of  3/  12/  01  at  pg.  7.  See  COSPAS-SARSAT 
 LEOLUT  Performance  Specifications  and  Design  Guidelines,  Document  C/  S  T.  002,  Issue  3,  Rev.  1  (Oct.  1999)  in  Section  3.5  at  3-  1.  This  states  that  the  LUT  shall  be  able  to  track  the  LEO  SARSATs  when  they  reach  5 

 degrees  above  the  horizon. 
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 expected  interference  to  radars  from  systems  using  Orthogonal  Frequency  Division  Multiplex  (OFDM)  modulation  methods.  The  proposal  to  change  the  I/  N  to  12  dB  also  includes  noise  like  interference 
 sources,  and  is  not  solely  based  on  an  OFDM  type  emission.  211  However,  the  10  dB  level  is  the  agreed  upon  U.  S.  position  with  the  ITU  and  is  appropriate  for  this  analysis.  In  calculating  the  required  emission 
 limits  for  UWB  devices  to  protect  the  ASR-  9,  NTIA  used  average  antenna  heights  and  antenna  tilt  angles.  Only  indoor  UWB  operation  in  a  30  m  building  exceeds  the  predicted  protection  limit  for  the  ASR-  9. 
 The  ASR-  9  requires  a  limitation  of  the  EIRPs  of  UWB  devices  operating  inside  buildings  to  57  dBm,  while  the  proposed  limit  for  indoor  UWB  devices  in  this  band  is  51.3  dBm.  Further  calculations  show 
 that  if  the  protection  level  is  51.3  dBm,  the  required  separation  distance  for  a  UWB  operating  at  this  EIRP  level  is  270  meters.  This  3.7  dB  difference  effectively  would  reduce  the  I/  N  from  10  to  6  for  this 
 system  and  would  increase  the  noise  floor  by  1  dB  instead  of    dB.  While  NTIA  indicates  that  this  would  diminish  the  capabilities  of  this  radar  in  the  same  azimuth  of  the  building,  NTIA  concluded  that  it 
 is  not  as  severe  a  problem  as  the  reduction  of  the  coverage  in  this  azimuth  due  to  the  physical  line-  of-  sight  blockage  caused  by  a  10-  story  building  within  270  meters  of  an  ASR-  9. 

 136.  NEXRAD.  This  radar  provides  quantitative  and  automated  real-  time  information  on  storms,  precipitation,  hurricanes,  tornadoes,  and  a  host  of  other  important  weather  information.  We  note 
 that  NTIA  refers  to  ITU-  R  M.  1464,  the  same  specification  called  out  for  the  ASR-  9  but  uses  a  level  of  6  dB  below  the  noise  floor  as  the  applicable  protection  level  since  the  NEXRAD  radar  is  used  for 
 meteorological  purposes.  Only  indoor  UWB  operation  in  a  30  m  building  less  than  760  meters  away  exceeds  the  predicted  protection  limit  for  the  NEXRAD.  The  NEXRAD  requires  a  limitation  of  the 
 EIRPs  of  UWB  devices  operating  inside  buildings  to  -57.3  dBm,  while  the  proposed  limit  for  indoor  UWB  devices  in  this  band  is  51.3  dBm.  Given  the  0.5-  degree  minimum  elevation  angle  of  the  antenna 
 mainbeam,  the  beam  would  only  be  6.6  meters  above  the  ground  at  270  meters.  The  building  itself  would  at  least  partially  obstruct  the  3  dB  beam  width  of  the  mainbeam  and  be  the  limiting  factor  along  the  given 
 azimuth  and  not  the  UWBs  EIRP.  An  elevation  angle  of  greater  than  2  degrees  is  required  to  clear  a  30-  meter  obstacle  at  a  distance  of  270  meters. 

 137.  Our  analysis  of  this  weather  radar  examined  the  possible  locations  of  the  UWB  devices  that  were  required  to  produce  an  interference  level  6  dB  below  the  radar  noise  floor.  At  these  locations, 
 we  computed  the  field  strength  emitted  by  the  radar.  We  concluded  that  UWB  devices  would  not  be  found  at  these  locations  because  the  radar  fields  were  large  enough  to  disrupt  the  operation  of  standard 
 electronic  devices.  We  also  were  informed  of  NOAAs  siting  criteria  212  that  requires  a  large  exclusion  area  around  the  radar  to  assure  operational  capability.  We  were  unable  to  confirm  that  such  exclusion 
 areas  actually  exist  as  required  due  to  the  absence  of  site  specific  data  showing  the  distance  and  location  of  large  buildings  around  the  radar  sites.  Therefore,  we  deferred  to  the  NTIA  analysis  values  for  this 
 system.  These  remarks  also  apply  to  the  TDWR  weather  radar. 
 138.  Marine  Radionavigation  Radar.  These  S-  band  radars  provide  information  on  surface  craft  locations,  obstructions,  buoy  markers,  and  navigation  marks,  e.  g.,  shore-  based  beacons  and  radar 

 beacons  to  assist  in  navigation  and  collision  avoidance.  NTIA  employed  an  I/  N  protection  criterion  of  10  dB,  indicating  that  this  level  is  contained  in  a  proposed  revision  to  ITU-  R  M.  1313-  1  under  consideration 
 by  ITU-  R  Study  Group  8  and  entitled,  Technical  Characteristics  of  Maritime  Radionavigation  Radars.  Only  the  level  proposed  for  UWB  indoor  operation  at  30  meters  height  exceeds  the  calculations  for 
 maritime  radar.  Indoor  UWB  operations  in  this  band  will  be  limited  to  51.3  dBm.  The  level  computed  for  protection  of  marine  radar  was  56  dBm.  The  distance  at  which  a  UWB  with  an  EIRP  of  51.3  dBm 

 211  Study  on  2700-  2900  MHz  Frequency  Band  Sharing  Between  Existing  Aeronautical  Radar  Equipment  and 
 Planned  Digital  ENG/  OB  and  digital  Aeronautical  Telemetry  Services,  EUROCONTROL,  Edition  Date  29/  05/  2001.  212 
 See  XSI  ex  parte  comments  of  February  4,  2002,  at  pg.  21-  22.  XSI  also  indicates  that  there  are  similar  FAA  siting  requirements  for  its  radar  systems. 
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 satisfies  the  protection  criteria  equation  is  370  meters.  At  such  a  close  separation  distance,  it  does  not  appear  that  marine  radionavigation  radar  systems  would  receive  harmful  interference  from  UWB 
 operations.  As  shipboard  UWB  operation  is  prohibited  at  the  request  of  NTIA,  marine  radar  systems  must  be  less  than  370  meters  from  land  in  order  to  receive  interference  from  UWB  systems.  At  this 
 distance,  the  return  signal  from  the  target  being  detected  by  the  marine  radar  would  be  considerably  higher  than  the  signal  received  from  the  UWB  device.  Accordingly,  no  harmful  interference  would  occur. 

 139.  FSS.  These  4-  GHz  earth  stations  are  used  to  receive  downlink  transmissions  from  geosynchronous  satellites  for  a  variety  of  applications  including  voice,  data,  and  video  services  for 
 Government  agencies.  NTIA  examined  interactions  with  FSS  systems  employing  antenna  elevation  angles  of  20  degrees  and  5  degrees.  NTIA  used  an  I/  N  protection  criterion  of  10  dB  based  on  a  general 
 discussion  of  factors  affecting  the  sensitivity  of  digital  communication  systems.  Only  the  level  proposed  for  UWB  indoor  operation  at  30-  meter  heights  exceeds  the  calculations  for  protection  of  receivers  in  the 
 fixed  satellite  service  with  an  elevation  angle  of  8.  Emissions  from  indoor  UWB  operations  in  this  band  will  be  limited  to  51.3  dBm.  The  level  computed  for  protection  of  FSS  receivers  with  an  elevation  angle 
 of  8  degrees  was  67  dBm.  For  the  proposed  level  of  51.3  dBm,  the  required  separation  distance  to  satisfy  the  protection  criterion,  a  separation  distance  of  240  meters  must  be  maintained.  For  the  given 
 scenario  of  an  FSS  earth  station  with  an  8  elevation  angle,  if  the  separation  distance  is  less  than  240  meters,  a  30  meter  building  would  at  least  partially  obstruct  the  3  dB  beamwidth  of  the  mainbeam  of  the 
 earth  station  antenna  based  purely  on  the  geometry  of  the  scenario.  Hence  the  level  41.3  dBm  appears  adequate. 

 140.  Our  analysis  of  the  FSS  noted  that  the  NTIA  protection  criterion  was  not  referenced  from  a  specific  standard  or  recognized  criterion.  FSS  is  a  digital  communications  system,  and  as  discussed  in 
 the  SARSAT  analysis,  we  believe  the  noise  floor  should  be  applied  as  the  protection  level,  i.  e.,  an  I/  N  of  0  dB.  We  applied  the  analysis  procedure  found  in  the  Radio  Regulations  of  the  ITU  213  and  concluded  that 
 for  an  I/  N  of  0  dB,  UWB  interference  would  not  be  allowed  to  occur  for  more  than  2.5%  of  the  time  without  requiring  coordination.  We  considered  that  UWB  devices  in  tall  buildings  would  not  be  an 
 interference  risk  for  the  FSS  terminals.  The  FSS  antenna  would  not  point  at  a  building  since  the  building  would  block  signals  from  the  satellite.  We  were  unable  to  confirm  this  conjecture  because  of  the  absence 
 of  site  specific  data  showing  the  distance  and  location  of  large  buildings  around  the  FSS  sites.  Therefore,  we  defer  to  the  NTIA  analysis  values  for  this  system. 

 141.  CW  and  Pulsed  Radar  Altimeters.  These  systems  provide  pilots  of  civil  and  military  aircraft  and,  through  them,  air  traffic  controllers  with  information  on  the  height  of  an  aircraft  above 
 ground  level.  NTIAs  investigation  demonstrated  that  UWB  devices  operating  at  the  Part  15  general  emission  limits  would  not  result  in  interference  to  these  operations.  For  that  reason,  we  have  not 
 investigated  these  systems  in  any  greater  detail. 
 142.  Microwave  Landing  Systems.  These  systems  are  used  for  precision  approach  and  landing  of  civilian  and  military  aircraft.  The  MLS  ground  station  supports  navigation  and  guidance  out  to  a  range 

 of  43  km  at  an  altitude  of  20,000  feet.  NTIA  stated  that  RF  interference  could  lead  to  errors  in  the  estimation  of  time  intervals  associated  with  beam  passage  of  the  MLS  transmitting  stations  antenna 
 beam.  214  It  added  that,  depending  on  the  frequency  components  of  the  error  process  and  the  aircraft  flight  control  system  guidance  loop  bandwidth,  this  could  lead  to  the  physical  displacement  of  the  aircraft 
 relative  to  the  desired  approach  path.  NTIA  added  that  the  ICAO  specified  the  maximum  permissible 
 213  Radio  Regulations  of  the  ITU,  Appendix  7,  Method  for  the  Determination  of  the  Coordination  Area  Around 
 an  Earth  Station  in  Frequency  Bands  Between  1  GHz  and  40  GHz  Shared  Between  Space  and  Terrestrial  Radiocommunications  Services.  Section  2.  3,  Derivation  and  Tabulation  of  Interference  Parameters,  and  Section 

 2.3.1,  Permissible  Level  of  the  Interfering  Emission,  was  applied.  214 
 NTIA  Special  Publication  01-  43,  supra,  at  pg.  A-  17. 
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 interference  power  into  a  MLS  receiver  as  130  dBm  to  prevent  this  from  occurring.  215  NTIA  subtracted  4  dB  from  the  ICAO  threshold  to  partition  the  UWB  interference  into  the  link  budget,  resulting  in 
 NTIAs  maximum  permissible  UWB  interference  level  of  134  dBm,  a  level  that  is  22  dB  below  the  thermal  noise  floor  of  the  MLS  receiver  and  31  dB  below  the  sensitivity  of  the  MLS  receiver.  NTIA 
 employed  a  5-  dBi  gain  antenna,  the  maximum  available  to  the  aircraft  at  an  angle  of  about  30  degrees  below  the  horizontal. 

 143.  Our  analysis  of  the  MLS  focused  on  two  approaches.  First,  the  receiver  noise  floor  is    112  dBm,  and  the  ICAO  maximum  interference  level  is  130  dBm.  This  interference  level  is  18  dB 
 below  the  noise  floor  and  27  dB  below  the  sensitivity  level  of  the  receiver.  An  interfering  signal  at  18  dB  below  the  noise  floor  would  result  in  an  increase  to  the  MLS  receiver  noise  floor  of  only  0.07  dB.  Such  a 
 small  increase  in  the  noise  floor  is  not  detectable  by  the  receiver  or  by  measurement  instrumentation.  We  believe  that  employing  the  ICAO  value  as  a  protection  criterion  is  overly  conservative  for  this  system. 
 Further,  we  do  not  agree  with  the  comments  from  Rockwell  stating  that  the  4  dB  additional  safety  margin  added  by  NTIA  is  inadequate  for  MLS  operation  in  a  Category  III  approach.  Rockwell  did  not  provide 
 any  justification  for  an  additional  safety  margin.  Indeed,  we  believe  that  the  ICAO  threshold,  even  without  the  4  dB  additional  safety  margin  applied  by  NTIA,  is  too  conservative.  Second,  we  note  that 
 NTIA  calculated  that  harmful  interference  would  be  caused  to  MLS  from  a  UWB  transmitter  operating  at  the  Part  15  general  emission  limits  at  a  maximum  separation  distance  of  160  meters.  We  also  note  that  the 
 expected  operating  range  of  the  MLS  system  is  43  km  at  an  altitude  of  20,000  feet.  There  is  little  likelihood  that  at  this  range  from  the  MLS  transmitter  the  aircraft  will  be  within  160  meters  of  a  UWB 
 transmitter.  As  the  aircraft  approaches  the  ground,  it  will  come  much  closer  to  the  MLS  transmitter,  increasing  the  level  of  the  received  signal  to  the  point  that  the  MLS  signal  would  be  considerably  greater 
 than  the  signal  level  from  a  UWB  transmitter  operating  at  the  Part  15  general  limits.  216  NTIA  also  stated  that  its  calculations  were  based  on  the  aircraft  being  at  a  height  of  30  meters.  At  this  height,  the  aircraft 
 would  be  near  the  MLS  transmitter,  whose  signal  level  would  override  any  potential  interference. 
 144.  TDWR.  These  radars  operate  in  the  5600-  5650  MHz  band  and  provide  measurements  of  gust  fronts,  microbursts,  and  other  weather  hazards  at  for  improving  safety  operations  at  major  airports  in 

 the  United  States.  They  are  located  within  24  kilometers  (15  miles)  of  airports  and  need  to  have  a  clear  line-  of-  sight  (LOS)  at  the  runway  to  observe  weather  phenomena  for  aircraft  approaches  and  landings. 
 Indoor  UWB  operation  is  the  only  UWB  operation  not  directly  protected  by  the  proposed  limits.  The  proposed  UWB  EIRP  level  for  this  band  is  41.3  dBm  which  is  8  dB  above  the  calculated  EIRP.  To 
 achieve  the  required  protection  for  the  TDWR,  a  UWB  located  in  a  30-  meter  building  would  have  to  be  located  1370  meters  away.  Given  the  0.2  minimum  elevation  angle  of  the  antenna  mainbeam,  the  beam 
 would  only  be  5  meters  above  the  horizon.  The  building  itself  would  at  least  partially  obstruct  the  3  dB  beamwidth  of  the  mainbeam  and  be  the  limiting  factor  along  the  given  azimuth  and  not  the  UWBs  EIRP. 
 An  elevation  angle  of  greater  than  1.25  degrees  is  required  to  clear  a  30-  meter  obstacle  at  a  distance  of  1370  meters.  Therefore,  the  geometry  of  the  TDWR  is  the  limiting  factor  for  this  scenario,  not  the  EIRP 
 of  the  UWB. 

 215  International  Standards  and  Recommended  Practices  Annex  10  to  the  Convention  of  International  Civil 
 Aviation,  Volume  1  (Radio  Navigation  Aids)  Fifth  Edition,  July  1996.  216 
 In  order  for  the  aircraft  to  be  within  160  meters,  horizontal,  from  the  UWB  transmitter  at  a  receive  angle  of  30  degrees,  as  employed  by  NTIA  in  its  calculations,  the  aircraft  would  be  less  than  93  meters  above  the  ground. 
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 Table  7.  Maximum  UWB  EIRP  for  UWB  Use  Indoors 
 System  Frequency  (MHz) 
 Maximum  UWB  EIRP 
 (dBm/  MHz)  UWB 
 Indoors  2  m  height 

 Maximum  UWB  EIRP 
 (dBm/  MHz)  UWB 
 Indoors  30  m  height 

 Average  Building 
 Attenuation  Losses  217 
 (dB) 
 DME,  Interrogator  960-  1215  -38  Not  Applicable  218  9 
 DME,  Transponder  1025-  1150  -55  -48  9 
 ATCRBS,  Transponder  1030  -35  Not  Applicable  9 

 ATCRBS,  Interrogator  1090  -22  -35  9 
 ARSR-  4  1240-  1370  -52  -73  9 
 SARSAT  1544-  1545  -60  -57  9 
 ASR-  9  2700-  2900  -37  -57  9 
 NEXRAD  2700-  2900  -33  -67  9 
 Marine  Radar  2900-  3100  -34  -45  12 
 FSS,  20  degrees  3700-  4200  -24  -30  12 
 FSS,  5  degrees  3700-  4200  -39  -65  12 
 CW  Altimeters  4200-  4400  37  Not  Applicable  12 
 Pulsed  Altimeters  4200-  4400  26  Not  Applicable  12 
 MLS  5030-  5091  -42  Not  Applicable  12 
 TDWR  5600-  5650  -23  -51  12 

 145.  The  above  table  reflects  NTIAs  calculation  of  the  maximum  signal  levels  that  could  be  permitted  for  UWB  devices  operated  indoors.  The  possibility  of  restricting  most  applications  of  UWB 
 technology  to  indoor  use  but  imaging  and  vehicular  radar  applications  was  not  considered  in  the  NTIA  analysis  because  it  was  not  specifically  proposed  in  the  Notice.  Thus,  the  constraints  NTIAs  analysis 
 originally  concluded  were  necessary  to  protect  government  receivers  from  outdoor  use  of  UWB  devices  must  be  reformulated  to  account  for  the  indoor  use  of  UWB  devices  and  the  inherent  additional  expected 
 propagation  attenuation.  This  is  done  by  simply  adding  a  term  for  the  value  of  expected  building  attenuation  as  a  function  of  frequency  to  the  link  budget  analysis  model  described  earlier.  The  column  on 
 the  far  right  contains  the  average  building  attenuation  factor.  NTIA  analyzed  UWB  devices  operating  in-doors  at  heights  of  2  meters  (roughly  equivalent  to  ground  level)  and  30  meters  (roughly  equivalent  to  the 
 tenth  floor  in  a  typical  suburban,  office  building)  and  calculated  the  maximum  allowable  UWB  EIRP.  The  building  attenuation  level  was  subtracted  from  the  values  NTIA  obtained  in  Table  6  to  obtain  the 
 indoor  limits  at  a  2  meter  height.  The  results  of  the  NTIA  analyses  are  summarized  in  Table  7. 
 146.  UWB  Interference  due  to  Peak  Emission  Levels.  NTIA  also  performed  a  limited  analysis  of  potential  interference  to  SARSAT  and  FSS  stations  due  to  the  peak  level  of  the  UWB  transmitter. 

 However,  NTIA  did  not  consider  the  proposed  limits  on  peak  power  levels  in  the  Notice,  since  their  measurements  did  not  show  a  need  for  such  limits  for  analog  systems  and  only  very  limited 

 217  NTIA  Report  95-  325,  Building  Attenuation,  at  pg.  43. 
 218  Not  Applicable  indicates  that  the  particular  scenario  would  involve  an  airborne  receiver  at  the  same 
 altitude  as  a  UWB  transmitter,  which  should  not  occur. 
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 measurements  were  made  on  digital  systems.  No  conclusion  can  be  made  from  the  peak  power  analysis  due  to  the  non-  linear  nature  of  the  digital  systems,  unique  error  correcting  schemes,  and  unknown 
 characteristics  of  individual  UWB  systems  operating  in  these  bands.  The  actual  impact  to  a  digital  wideband  system  from  the  peak  power  received  from  a  UWB  device  will  depend  on  many  receiver 
 parameters  not  generally  available  such  as  modulation  scheme,  and  bit  error  rates.  As  a  result,  the  peak  values  NTIA  used  for  its  analysis  are  far  in  excess  of  the  levels  the  Commission  proposed  in  the  Notice.  219 
 Consequently,  we  do  not  envision  interference  problems  from  peak  emissions  from  UWB  devices  if  the  peak  power  limits  proposed  in  the  Notice  are  embraced. 

 3.  U.  S.  Department  of  Defense  Analysis  of  Interference  to  the  SGLS 
 147.  DOD  provided  a  mathematical  analysis  of  possible  interference  from  UWB  operation  to  its  Space-  Ground  Link  Subsystem  (SGLS)  at  2.2-  2.3  GHz.  220  DOD  applied  free  space  attenuation 

 without  intervening  objects,  assumed  a  noise-  like  UWB  emission,  and  applied  SGLS  receive  antenna  gains  ranging  from  6  to  26  dB  corresponding  to  antenna  elevation  angles  ranging  from  20  to  3  degrees. 
 Interference  was  defined  with  I/  N  ranging  from  +17.5  dB  to  5.4  dB.  It  calculated  minimum  separation  distances  ranging  from  19  meters  to  1.522  km. 

 148.  Few  details  were  included  with  the  DOD  analysis.  We  do  not  agree  that  it  is  appropriate  to  use  free  space  analysis  or  to  assume  the  lack  of  intervening  objects  in  determining  propagation 
 attenuation.  We  also  do  not  believe  that  these  DOD  satellite  receive  stations  will  be  located  in  areas  were  UWB  devices  would  be  sufficiently  close  to  cause  interference  problems,  especially  with  the  operational 
 constraints  we  are  adopting  in  this  proceeding.  Similarly,  as  with  the  SARSAT  and  FSS  stations,  these  antennas  will  not  be  directed  at  buildings  or  other  structures  that  would  block  reception  of  the  satellite 
 transmissions. 
 4.  ARRL  Analysis  of  Noise  Floor  Increase  in  Amateur  Radio  Bands 
 149.  The  ARRL  presented  analyses  of  potential  increases  in  the  noise  floor  in  the  Amateur  Radio  Service  frequency  bands  at  420-  450  MHz  (420  MHz)  and  2400-  2450  MHz  (2450  MHz).  ARRL 

 performed  calculations  to  show  that  an  amateur  radio  receiver  operating  in  the  420  MHz  band,  using  a  20  dBi  receive  antenna  gain  and  a  receiver  bandwidth  of  1  kHz  would  experience  a  56.5  dB  increase  in  the 
 noise  floor  at  a  distance  of  30  meters  from  an  UWB  transmitter  operating  with  an  average  EIRP  of  80  dBm/  Hz  (0  dBm/  100  MHz).  Similar  calculations  were  performed  showing  that  an  amateur  radio  receiver 
 operating  in  the  2450  MHz  band  using  a  0  dBi  or  a  20  dBi  receive  antenna  gain  and  a  receiver  bandwidth  of  1  kHz  would  experience  a  11.4  and  31  dB  increase,  respectively,  in  the  noise  floor  at  a  distance  of  30 
 meters  from  a  UWB  transmitter  operating  with  an  average  EIRP  of  90  dBm/  Hz  (0  dBm/  GHz).  221  Additional  calculations  showed  that  the  increase  in  the  receiver  noise  floor  did  not  change  if  the  receiver 
 bandwidth  was  increased  from  1  kHz  to  10  kHz  or  from  1  kHz  to  50  MHz.  222 
 150.  We  find  that  ARRLs  calculations  overestimate  the  potential  increase  in  the  noise  floor  to  amateur  radio  receivers  from  UWB  devices.  As  an  initial  matter,  the  use  of  the  thermal  noise  floor  of  a 

 receiver  is  not  a  reasonable  approach  for  evaluating  whether  or  not  harmful  interference  may  occur.  The  thermal  noise  floor  represents  the  minimum  signal  level  that  can  be  received  under  ideal  conditions.  In 

 219  The  primary  effect  of  the  Commissions  peak  power  limits  as  proposed  in  the  Notice  is  that  the  peak  power 
 limit  provides  the  restriction  at  lower  PRFs  while  the  average  power  limit  provides  the  restriction  at  higher  PRFs.  .  220 
 Attachments  to  U.  S.  Department  of  Defense  filing  of  10/  1/  00.  221 
 ARRL  employed  a  receiver  noise  level  of  141  dBm  and  a  noise  figure  of  3  dB,  resulting  in  a  thermal  noise  floor  of  139  dBm,  for  both  1  kHz  bandwidth  receivers  used  in  its  analyses. 

 222  This  would  be  expected  with  a  constant  envelope  signal  level. 
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 practice,  the  actual  received  signal  levels  are  typically  well  above  the  thermal  noise  floor  of  the  receiver.  ARRL  assumed  that  the  UWB  transmitter  would  be  operating  at  an  average  EIRP  of  80  dBm/  Hz  at  420 
 MHz  or  at  90  dBm/  Hz  at  2500  MHz.  The  specific  limits  proposed  in  the  Notice  were  200  uV/  m,  as  measured  at  3  meters  with  a  quasi-  peak  detector,  for  420  MHz  and  500  uV/  m,  as  measured  at  3  meters 
 with  an  average  detector  and  a  1  MHz  resolution  bandwidth,  for  2450  MHz.  These  limits  are  equivalent  to  an  EIRP  of  12  nW/  120  kHz  223  or  49.  2  dBm/  120  kHz  or  100  dBm/  Hz  at  420  MHz  and  to  an  EIRP  of 
 75  nW/  MHz  or  41.25  dBm/  MHz  or  101.25  dBm/  Hz  at  2450  MHz.  Therefore,  the  levels  ARRL  applied  to  the  UWB  emissions  are  11  to  20  dB  higher  than  those  proposed  in  the  Notice.  We  also  believe  that  it  is 
 extremely  unlikely  that  the  UWB  emission  would  be  in  the  main  beam  of  a  20  dBi  gain  antenna,  particularly  given  the  operating  restrictions  we  are  applying  to  UWB  devices.  224  Adjusting  ARRLs 
 analyses  to  take  these  factors  into  account  substantially  reduces  ARRLs  estimate  of  the  increase  in  the  noise  floor  of  the  receivers. 

 151.  In  addition,  we  note  that  Part  15  devices  already  operate  in  the  2400-  2450  MHz  band  used  by  the  amateur  radio  service  at  considerably  higher  power  levels  that  those  proposed  in  the  Notice. 
 For  example,  frequency  hopping  spread  spectrum  transmitters  are  permitted  to  operate  at  a  signal  level  of  36  dBm/  MHz  and  at  even  higher  signal  levels  for  fixed  point-  to-  point  links.  Similarly,  microwave  ovens 
 and  other  Part  18  devices  are  permitted  to  operate  on  a  primary  basis  within  this  frequency  band  without  a  limit  on  the  level  of  their  emissions.  Nevertheless,  amateurs  have  coexisted  successfully  with  these 
 devices.  This  leads  us  to  conclude  that  it  is  unlikely  that  UWB  devices  will  have  any  significant  impact  on  Amateur  operations  in  this  spectrum.  We  find  nothing  in  the  ARRL  analysis  that  leads  us  to  conclude 
 that  the  existing  Part  15  emissions  limits  are  inadequate  to  control  interference  from  UWB  devices  to  the  Amateur  Radio  Service. 

 5.  Analyses  of  Potential  Interference  to  PCS 
 152.  Several  parties  performed  tests  and  analysis  of  potential  interference  to  PCS  systems  operating  in  the  1850    1910  MHz  and  1930  -1990  MHz  bands.  225  These  studies  are  discussed  in  the 

 following  paragraphs. 
 153.  Motorola  Analysis.  Motorola  performed  mathematical  analyses  of  potential  interference  from  UWB  devices  to  PCS  systems.  Motorola  bases  its  definition  of  harmful  interference  on  a  PCS 

 receiver  as  any  signal  that  causes  a  1  dB  rise  in  the  receiver  thermal  noise  floor,  i.  e.,  resulting  from  an  UWB  device  that  produces  signal  in  the  PCS  receiver  that  is  6  dB  below  the  thermal  noise  floor. 
 Motorola  assumed  that  the  receiver  would  have  a  10  dB  noise  figure  and  an  antenna  with  8  dBi  of  gain.  Using  free  space  attenuation,  it  calculated  that  the  UWB  and  the  PCS  receiver  must  be  separated  by  at 
 least  13  meters.  It  then  demonstrated  how  this  separation  distance  increased  with  increasing  antenna  gain  such  that  the  minimum  separation  distance  becomes  65  meters  when  the  receiving  antenna  gain  is 
 increased  to  +6  dBi,  i.  e.,  the  antenna  employed  with  a  base  station. 
 154.  Protecting  the  PCS  receiver  to  a  level  6  dB  below  the  thermal  threshold  of  the  receiver  is  not  reasonable  because  it  represents  the  ideal  performance  of  the  receiver  and  is  not  representative  of 

 223  At  the  PRFs  commonly  employed  by  UWB  transmitters,  it  is  expected  that  a  quasi-  peak  detector  will  tend 
 to  measure  closer  to  the  peak  level  as  opposed  to  the  average  level.  However,  the  amateur  narrowband  receiver  would  respond  to  the  average  level  of  the  UWB  emission.  This  could  be  considerably  less  than  the  peak  level.  In 

 any  event,  the  devices  operating  below  1  GHz  will  be  extremely  limited  in  number  and  scope  and  should  not  be  a  source  of  interference. 
 224  While  a  20  dBi  Yagi  antenna  is  feasible,  such  an  antenna  normally  would  be  mounted  high  above  a  roof 
 where  it  is  unlikely  that  a  nearby  UWB  transmitter  would  be  directly  in  the  main  beam.  225 
 It  should  be  noted  that  the  PCS  frequency  bands  are  not  restricted  bands.  Part  15  devices  currently  are  permitted  to  transmit  in  the  PCS  bands  at  a  level  equivalent  to  41.  25  dBm/  MHz  EIRP. 
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 typical  operating  conditions.  In  practice,  PCS  receivers  will  normally  receive  signals  well  above  the  thermal  threshold  of  the  receiver.  Thus,  Motorolas  analysis  affects  receivers  operating  at  the  fringe  of  a 
 reception  area.  In  addition,  it  is  likely  that  intervening  objects  would  provide  significant  attenuation  to  UWB  emissions.  Thus,  we  do  not  believe  that  Motorolas  calculations  provide  a  reasonable 
 representation  of  the  interference  potential  of  UWB  to  PCS  operations. 
 155.  Sprint  PCS,  Time  Domain  Corporation  and  Telcordia  Analyses.  Sprint  PCS  and  TDC  jointly  submitted  two  documents.  The  first  was  a  theoretical  model  developed  by  Telcordia  Technologies 

 to  analyze  the  impact  of  UWB  on  the  forward  link  on  a  CDMA  PCS  network.  The  second  summarized  tests  conducted  by  Sprint  PCS,  Time  Domain  and  Telcordia.  These  tests  included  laboratory  evaluations, 
 over  the  air  transmissions  in  an  anechoic  chamber,  and  field  simulations.  The  over-  the-  air  test  conducted  in  an  anechoic  chamber  demonstrated  the  following  226  :  (1)  free  space  attenuation  is  appropriate  for  this 
 type  of  test;  (2)  the  PCS  handset  had  an  antenna  gain  of  4.6  dBi;  227  (3)  the  RSSI  measured  by  the  handset  was  3  dB  different  from  computed  values;  228  (4)  the  measured  E/  N  for  the  onset  of  frame  errors  was  5  dB, 
 consistent  with  expectations;  (5)  the  handset  power  varied  by  1.5  to  2.5  dB  due  to  antenna  polarization  and  by  12  to  15  dB  use  to  head  loss,  i.  e.,  signal  blocking  by  the  user;  and  (6)  the  effect  of  UWB  IX 
 appears  to  be  the  same  as  Gaussian  noise.  229  Much  of  the  data  from  the  open  field  tests  was  lost.  230  The  available  test  data  employed  an  RSSI  (total  forward  power  received  by  the  handset)  of  between  92  dBm 
 and  96  dBm.  As  only  a  single  test  cell  was  activated,  no  account  was  taken  of  potential  interference  from  other  nearby  cells.  The  minimum  UWB  separation  distance  to  avoid  interference  at  that  signal  level  was 
 found  to  be  about  0.35  to  0.  56  meters.  The  call  was  dropped  when  the  UWB  emitter  was  moved  to  within  about  0.3  meters  of  the  PCS  handset.  231  It  also  was  noted  that  with  a  fully  loaded  system  this  distance 
 range  would  apply  with  the  RSSI  at  about  7  dB  greater,  i.  e.,  at  85  dBm  to  89  dBm.  Several  comments  were  filed  in  response  to  this  test. 

 156.  Sprint  PCS  stated  that  these  tests  confirm  that  a  UWB  emission  at  a  level  12  dB  below  the  general  limits  in  47  C.  F.  R.    15.209  will  cause  interference  to  a  PCS  CDMA  system,  resulting  in  the 
 handset,  operating  with  a  PCS  received  signal  of  100  dBm,  requesting  50  percent  more  power  when  only  2  meters  from  the  UWB  transmitter.  232  It  added  that  a  separate  effect  of  UWB  interference  is  call 
 blocking  such  that  if  between  one  in  twenty  and  one  in  five  PCS  customers  are  within  2  meters  of  active  UWB  transmitters  2  percent  to  7.9  percent  of  calls  will  be  dropped  or  call  attempts  will  be  blocked.  233 

 157.  On  the  other  hand,  TDC  believes  that  the  theoretical  model  of  Telcordia  does  not  accurately  describe  the  results  of  real  world  open  field  testing,  adding  that  it  is  not  possible  for  the  PCS 
 receivers  to  detect  UWB  emissions  even  at  separation  distances  less  than  1  meter.  234  It  stated  that  the  PCS  phone  performance  was  dramatically  better  in  an  anechoic  chamber  than  in  an  open  field  even 

 226  See  Sprint  PCS  comments  of  9/  12/  2000  at  Attachment  2,  pg.  2-  3. 
 227  In  the  anechoic  chamber  test,  it  appeared  that  the  antenna  was  optimized  for  the  transmit  band  rather  than 
 the  receive  band  resulting  in  a  measured  gain  of  4.6  dBi.  228 
 Thus,  the  losses  between  the  antenna  and  the  receiver  are  greater  than  those  used  in  the  above  calculations.  229 
 Qualcomm  stated  that  for  commercial  CDMA  receivers  it  does  not  matter  if  the  in-  band  noise  has  spectral  lines  or  is  white  spectrum;  what  matters  is  total  power  in  a  1.  2288  MHz  bandwidth.  See  Qualcomm  comments  of 

 5/  10/  01  at  pg.  14.  230 
 Sprint  PCS  comments  of  9/  12/  2000  at  Attachment  2,  pg.  4.  231 
 Sprint  PCS  comments  of  9/  12/  2000  at  Attachment  2,  pg.  4.  232 
 Sprint  PCS  comments  of  4/  6/  01  at  pg.  2.  233 
 Sprint  PCS  comments  of  4/  6/  01  at  pg.  2-  3.  234 
 TDC  comments  of  4/  25/  01  at  pg.  79. 
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 through  the  base  station  was  clearly  visible  to  the  handset  and  the  propagation  path  was  unobstructed.  235  According  to  TDC,  the  model  developed  by  Telcordia  predicted  that  in  an  anechoic  chamber  IS-  95 
 cellphones  should  not  experience  frame  error  rates  greater  than  2  percent  at  received  signals  levels  as  low  as  105  dBm;  however,  in  the  open  field  the  FER  would  jump  momentarily  to  as  much  as  8  percent  even 
 when  the  received  signal  was  as  great  at  85  dBm.  TDC  adds  that  extrapolation  from  testing  suggests  that  the  impact  of  the  UWB  emission  on  PCS  might  be  observable  when  the  PCS  signal  is  marginal,  at   
 95  dBm,  and  the  UWB  device  is  continually  transmitting  and  within  1.5  meters.  236  However,  it  concluded  that  this  was  a  conservative  estimate  since  during  the  open  field  testing  with  a  PCS  received  signal  level 
 of  between  92  dBm  and  95  dBm  no  impact  from  the  UWB  emission  was  seen  until  the  UWB  emitter  was  less  than  1  meter  from  the  PCS  cellphone. 

 158.  XSI  also  believes  that  the  earlier  Sprint  PCS/  TDC  tests  demonstrated  that  UWB  devices  would  not  cause  substantial  harmful  interference  to  PCS,  stating  that  the  claim  of  interference  is  based  on 
 numerous  unrealistic  assumptions  and  conflicting  results.  237  XSI  stated  that  it  is  important  to  note  that  the  anechoic  chamber  eliminated  all  external  RF  noise  and  any  potential  interference  due  to  other  CDMA 
 cells  or  multi-  path  which  it  says  are  the  most  important  factors  in  understanding  potential  interference  for  a  PCS  network.  238  The  test  that  was  performed  at  an  outdoor  facility  showed  that  the  PCS  handset 
 exhibited  a  rise  in  traffic  channel  power  and  then  dropped  a  call  only  when  a  UWB  transmitter  was  moved  to  within  approximately  0.3  meters  of  the  handset.  239  XSI  noted  that  the  Sprint  model  did  not 
 consider  non-  line-  of-  sight  propagation  effects,  nor  did  it  provide  an  allowance  for  interference  from  other  base  stations  although  this  effect  is  shown  to  be  significant,  resulting  in  as  much  as  a  5  dB  rise  in  the 
 effective  noise  floor.  240  XSI  concluded  that  the  live  testing  by  Sprint  PCS  showed  that  effects  such  as  interference,  noise,  and  Rayleigh  fading  were  severe  enough  to  mask  any  effects  predicted  by  the 
 analytical  model  until  the  UWB  emitter  was  moved  to  within  approximately  0.3  meters  of  the  PCS  handset.  241 

 159.  We  find  that  the  testing  in  the  anechoic  chamber  permitted  the  PCS  receiver  to  function  properly  down  to  the  thermal  noise  floor  of  the  receiver.  Once  this  equipment  was  placed  outdoors  in  a 
 simulated  environment,  the  UWB  emissions  had  no  significant  interference  effect  except  at  distances  less  than  one  meter.  We  find  that  it  is  extremely  unlikely  that  UWB  devices  will  be  located  this  close  to  a  PCS 
 receiver,  particularly  given  the  operating  restrictions  we  are  applying  to  UWB  devices.  Further,  we  do  not  believe  it  is  appropriate  to  use  such  a  close  separation  distance  as  the  basis  for  controlling  harmful 
 interference.  Any  interference  at  close  distances  can  be  easily  remedied  by  moving  the  devices  a  short  distance  apart. 

 160.  Qualcomm  Analysis.  Qualcomm  performed  a  mathematical  analysis  accompanied  by  laboratory  testing  using  a  PCS  simulator.  Based  on  its  mathematical  analysis,  Qualcomm  asserts  that  a 
 PCS  mobile  unit  would  need  to  be  at  least  24  meters  from  a  UWB  transmitter  operating  at  the  47  C.  F.  R.    15.209  limit  in  order  not  to  receive  harmful  interference.  A  more  detailed  discussion  of  the  Qualcomm 
 analysis  has  been  placed  in  the  docket  file  for  this  proceeding. 

 235  TDC  comments  of  4/  25/  01  at  pg.  83-  84. 
 236  TDC  comments  of  4/  25/  01  at  pg.  85. 
 237  XSI  comments  of  5/  10/  01  at  pg.  4. 
 238  XSI  comments  of  5/  10/  01  at  pg.  5-  6. 
 239  XSI  comments  of  5/  10/  01  at  pg.  6. 
 240  XSI  comments  of  5/  10/  01  at  pg.  7-  8. 
 241  XSI  comments  of  5/  10/  01  at  pg.  11. 
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 161.  We  observe  that  Qualcomms  mathematical  analysis  is  based  on  defining  harmful  interference  as  any  UWB  emission  that  is  greater  than  6  dB  below  the  thermal  noise  floor  of  the  PCS 
 receiver.  While  such  an  analysis  can  determine  if  a  signal  will  increase  the  receiver  noise  floor  in  situations  where  no  RF  background  noise  exists,  this  is  not  indicative  of  harmful  interference  to  a 
 communications  system.  Modifying  the  antenna  gain  to  4.6  dBi  to  reflect  the  measured  data  from  the  Sprint  analysis,  and  using  free  space  to  recalculate  the  minimum  separation  distance  necessary  to  prevent 
 harmful  interference  to  a  PCS  system,  we  find  that  a  UWB  transmitter  must  be  3.2  meters  from  the  PCS  receiver  if  the  UWB  transmitter  operates  at  the  limit  in  47  C.  F.  R.    15.209  and  0.8  meters  if  the  UWB 
 transmitter  operates  at  12  dB  below  the  limit  in  47  C.  F.  R.    15.209,  as  proposed  in  the  Notice.  These  separation  distances  are  based  on  worst  case  conditions  as  they  do  not  assume  that  there  is  additional 
 attenuation  of  the  UWB  emissions  due  to  intervening  objects,  mismatched  antenna  polarizations,  head  loss,  or  other  effects.  They  also  assume  that  the  UWB  transmitter  is  operating  at  its  maximum  emission 
 limit  with  the  emission  directed  at  the  PCS  receiver. 
 162.  The  laboratory  measurements  performed  by  Qualcomm  demonstrated  that  a  S/  I  of  about  a  6  dB  is  required  to  prevent  interference  to  a  PCS  system.  We  believe  that  a  PCS  received  signal  level  of   

 96  dBm/  1.25  MHz  adequately  characterizes  a  low  level  PCS  signal  level  based  on  real  world  applications.  242  Using  free  space  analysis,  this  PCS  signal  level  and  a  6  dB  S/  I  for  the  UWB  emission,  we 
 find  that  the  UWB  transmitter  must  be  7.2  meters  from  the  PCS  receiver  if  the  UWB  transmitter  operates  at  the  limit  in  47  C.  F.  R.    15.209  and  1.8  meters  if  the  UWB  transmitter  were  to  operate  at  12  dB  below 
 the  limit  in  47  C.  F.  R.    15.209.  Again,  these  separation  distances  are  based  on  worst  case  conditions  as  they  do  not  assume  that  there  is  additional  attenuation  of  the  UWB  emissions  due  to  intervening  objects, 
 mismatched  antenna  polarizations,  head  loss,  or  other  effects.  They  also  assume  that  the  UWB  transmitter  is  operating  at  its  maximum  emission  limit  with  the  emission  directed  at  the  PCS  receiver. 

 163.  Summary  of  findings  of  analyses  of  interference  to  PCS.  Upon  review  of  the  various  tests  and  analyses  submitted  in  the  record,  we  do  not  believe  that  UWB  devices  will  present  a  significant  risk 
 of  harmful  interference  to  PCS,  particularly  when  evaluated  under  actual  operating  conditions  instead  of  in  a  laboratory  environment.  Nevertheless,  given  that  we  are  applying  a  reduction  of  at  least  12  dB  in 
 emissions  in  the  GPS  frequency  band,  which  is  in  close  proximity  to  the  PCS  band,  in  an  abundance  of  caution  we  will  require  this  reduction  to  extend  through  the  PCS  band  to  1990  MHz.  We  do  not  believe 
 this  will  have  any  significant  impact  on  the  viability  of  UWB  devices.  Further,  this  will  ensure  against  interference  to  PCS  even  under  extremely  close  separation  distances. 

 6.  Cisco  Analysis  of  Potential  Interference  to  MMDS 
 164.  Cisco  presented  mathematical  analyses  to  demonstrate  that  a  single  UWB  transmitter  would  cause  a  significant  increase  to  the  noise  floor  of  a  MMDS  receiver  located  several  hundred  meters 

 away.  Attachment  2  to  its  comments  addressed  UWB  peak  emissions,  and  Attachment  3  to  its  comments  addressed  UWB  average  emissions.  With  regard  to  peak  emissions,  Cisco  calculated,  based  on  the 
 proposal  in  the  Notice  for  a  limit  on  total  peak  power,  that  a  UWB  transmitter  operating  with  a  pulse  width  of  one  nanosecond  and  possessing  a  1.5  gigahertz  10  dB  bandwidth  will  have  a  total  peak 
 emission  49.4  dB  greater  than  the  average  limit.  It  then  calculated  that  for  a  UWB  system  to  comply  with  a  49.4  dB  peak  to  average  ratio  it  must  operate  with  a  pulse  repetition  frequency  of  11.5  kHz.  243  As  this  is 
 less  than  the  12  MHz  bandwidth  employed  by  the  MMDS  receiver,  Cisco  calculated  that  the  peak  power  received  by  the  12  MHz  wide  receiver  will  be  44.1  dB  greater  than  the  average  UWB  received  power. 

 242  47  C.  F.  R.    24.236  states  that  the  median  field  strength  at  any  location  on  the  border  of  the  PCS  service 
 area  shall  not  exceed  47  dBuV/  m.  As  this  is  the  signal  level  established  in  the  rules  as  what  is  necessary  to  prevent  interference  to  an  adjacent  license,  it  appears  likely  that  PCS  systems  are  designed  to  operate  at  this  level  or  higher. 

 For  a  50  ohm  system,  this  emission  level  is  equivalent  to  a  received  signal  level  of  96  dBm.  243 
 No  limit  on  the  peak-  to-  average  ratio  was  proposed  in  the  Notice. 
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 165.  We  find  that  in  calculating  the  10  dB  bandwidth  of  the  UWB  transmitter  Cisco  assumed  the  use  of  a  perfect  antenna.  It  is  unlikely  that  an  antenna,  which  acts  as  a  band-  pass  filter,  would  pass  all 
 of  the  energy  over  a  1.5  gigahertz  bandwidth  centered  on  the  UWB  emission.  The  actual  total  peak  signal,  based  on  the  proposal  in  the  Notice,  may  be  lower  due  to  the  narrower  transmitted  bandwidth. 
 Cisco  also  assumed  that  the  UWB  transmitter  had  to  meet  a  peak-  to-  average  ratio  whereas  our  proposal  was  to  establish  an  average  limit  and  a  peak  limit  with  the  latter  consisting  of  two  parts:  a  total  peak 
 power  based  on  the  bandwidth  of  the  emission  and  a  peak  power  limit  based  on  a  50  MHz  bandwidth.  In  actual  practice,  a  UWB  transmitter  will  be  subject  to  the  average  limit  or  to  the  peak  limit  but  not  both. 
 Systems  with  low  PRFs  will  be  governed  by  the  peak  limits  and  systems  with  high  PRFs  will  be  governed  by  the  average  limits. 

 166.  With  regard  to  average  power  levels,  Cisco  modeled  a  2.5  GHz  sinusoidal  carrier  modulated  by  a  one  nanosecond  pulse  with  a  PRF  of  20  MHz.  Cisco  then  assumed  that  the  UWB 
 transmitter  operated  at  the  maximum  limit  and  was  pointed  directly  at  a  20  dBi  antenna  employed  by  the  MMDS  receiver.  Cisco  also  assumed  that  its  MMDS  operation  should  be  protected  to  at  least  a  level  of 
 10  dB  below  the  thermal  noise  floor  of  the  MMDS  receiver  without  adjusting  the  noise  floor  for  line  losses  and  the  receiver  noise  figure.  With  free  space  attenuation,  this  resulted  in  Cisco  calculating  a 
 minimum  separation  distance  of  380  meters.  Cisco  then  assumes  that  10  or  100  UWB  transmitters  all  are  emitting  at  the  maximum  allowable  emission  limit  at  2.5  GHz  and  are  all  pointed  directly  at  the  MMDS 
 antenna  to  show  how,  using  free  space  attenuation,  the  required  separation  distances  increase  to  1.2  km  and  3.9  km. 

 167.  We  find  that  the  protection  of  the  MMDS  receiver  to  a  level  10  dB  below  the  thermal  threshold  of  the  receiver  is  not  reasonable.  244  Second,  we  note  that  the  actual  thermal  noise  floor  of  the 
 MMDS  receiver  would  be  higher  than  that  calculated  by  Cisco  once  line  losses  and  the  receiver  noise  figure  are  included.  Unfortunately,  these  values  are  not  provided  by  Cisco  to  permit  the  calculations  to  be 
 redone.  Third,  at  the  distances  employed  free  space  is  not  a  practical  method  to  calculate  path  loss.  At  these  distances,  intervening  objects  would  provide  significant  attenuation  to  UWB  emissions.  Fourth,  it  is 
 extremely  unlikely  that  the  UWB  emission  could  be  pointed  at  the  main  beam  of  a  high-  gain  MMDS  antenna  because  such  antennas  generally  are  mounted  outside  on  roof  tops  or  on  the  sides  of  buildings. 
 Because  of  this  antenna  placement,  it  is  highly  unlikely  that  a  UWB  transmitter  would  be  close  to  an  MMDS  station  or  have  its  emissions  directed  within  the  mean  beam  of  the  MMDS  receiving  antenna.  As 
 with  the  SARSAT  and  FSS  stations,  MMDS  antennas  will  not  be  directed  at  buildings  or  other  structures  that  would  block  reception  of  the  MMDS  transmissions.  We  also  note  that  millions  of  other  RF  products, 
 such  as  spread  spectrum  transmitters  operating  in  the  2400-  2483.5  MHz  band  under  the  provisions  of  47  C.  F.  R.    15.247,  already  are  permitted  to  place  spurious  emissions  in  the  MMDS  bands  at  the  emission 
 level  proposed  in  the  Notice.  The  spread  spectrum  spurious  emissions  must  be  attenuated  to  41.25  dBm/  MHz,  245  the  same  level  proposed  for  UWB  emissions. 

 7.  XM  Analysis  of  Potential  Interference  to  DARS 
 168.  XM  performed  an  analysis  of  potential  interference  to  its  satellite  digital  audio  radio  service  operating  in  the  2332.5    2345  MHz  band.  XM  stated  that  its  satellite  receiver  operates  with  a 

 received  signal  of  109  dBm  to  90  dBm  with  a  noise  figure  of  1.2  dB  and  a  thermal  noise  of  110 

 244  See,  for  example,  Second  Memorandum  Opinion  and  Order  in  WT  Docket  No.  99-  168,  16  FCC  Rcd.  1239 
 (2001),  at  para.  6-  8.  245 
 This  is  the  limit  for  emissions  appearing  within  the  2483.  5-  2500  MHz  band.  The  limit  on  emissions  from  spread  spectrum  transmitters  appearing  within  the  MMDS  band  above  2500  MHz  is  about  +16  dBm  but  may  be 

 higher  for  high  gain  antennas  used  with  point-  to-  point  spread  spectrum  systems. 
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 dBm/  2  MHz.  246  XM  then  calculated,  using  free  space,  the  required  separation  distances  between  a  UWB  device  and  a  DARS  receiver  in  order  to  ensure  that  the  UWB  emissions  are  below  the  thermal  noise  floor 
 of  the  DARS  receiver.  At  a  level  of  41.25  dBm/  MHz,  XM  calculated  that  the  UWB  device  must  be  35  meters  from  the  DARS  receiver.  247  XM  also  stated`  that  the  required  S/  N  for  its  receiver  is  3  dB,  the  I/  N 
 is  67  dB  and  the  minimum  distance  from  an  interference  source  must  be  based  on  1  meter.  Accordingly,  XM  requests  that  the  emissions  from  UWB  devices  in  its  2332.5-  2345  MHz  band  be  limited  to  70  dBm. 

 169.  As  discussed  above,  harmful  interference  is  not  caused  to  a  receiver  from  a  radio  signal  that  is  below  the  thermal  noise  floor  of  a  victim  radiocommunications  receiver.  If  we  assume  that  the 
 UWB  signal,  emitting  at  41.25  dBm/  MHz,  may  not  exceed  the  DARS  receiver  thermal  noise  floor  of    110  dBm/  2  MHz,  an  attenuation  of  71.75  dB  is  required.  Free  space  at  2340  MHz  achieves  this 
 attenuation  at  a  separation  of  around  39  meters.  If  we  take  into  account  the  3  dB  loss  between  XMs  circular  polarized  antenna  and  the  linear  polarization  expected  from  UWB  operation,  the  separation  drops 
 to  27.  9  meters.  If  only  10  dB  of  attenuation  is  applied  to  the  UWB  emission,  the  minimum  separation  distance  decreases  to  8.8  meters.  This  is  not  an  excessive  separation  distance  for  a  receiving  system  that 
 generally  is  expected  to  be  mounted  outside  of  a  transportation  vehicle  or  on  the  roof  or  side  of  a  building.  Under  practical  operating  conditions,  there  would  be  further  attenuation  of  the  UWB  emissions  due  to  the 
 presence  of  intervening  objects,  misalignment  of  the  UWB  transmitting  and  DARS  receiving  antennas,  and  other  factors.  Further,  the  DARS  signal  normally  would  be  above  the  minimum  received  level 
 employed  in  this  calculation.  It  also  is  likely  that  the  UWB  emissions  would  be  somewhat  below  the  maximum  level  permitted  under  the  rules.  These  factors  would  considerably  shorten  the  calculated 
 interference  distance.  Vehicle  mounted  UWB  radar  systems,  which  will  be  located  closest  to  DARS  receivers,  are  being  required  to  operate  in  a  considerably  higher  frequency  band  than  that  used  by  DARS. 
 This  should  result  in  emissions  appearing  in  the  DARS  band  that  would  be  no  more  of  an  interference  threat  than  emissions  from  conventional  Part  15  devices.  248  In  any  event,  emissions  from  the  vehicular 
 radar  systems  would  likely  be  pointed  in  a  direction  other  than  at  the  DARS  antenna.  Further,  since  vehicle  manufacturers  will  provide  DARS  and  UWB  radar  systems  in  the  same  vehicle  the  vehicle 
 manufacturer  would  engineer  these  systems  to  ensure  that  there  is  no  mutual  interference.  We  also  note  that  DARS  will  be  supplemented  in  major  metropolitan  areas  with  high  powered  terrestrial  broadcasting 
 stations,  further  reducing  the  potential  for  harmful  interference. 
 8.  Summary  of  Tests  and  Analyses 
 170.  The  protection  levels  established  in  this  Order  primarily  are  those  determined  in  the  NTIA  analyses  of  Government  systems.  The  UWB  emissions  level  NTIA  developed  for  the  GPS  bands 

 provides  a  conservative  protection  level  for  all  of  the  government  and  commercial  systems  operating  between  960  MHz  and  1610  MHz.  We  find  that  the  various  analyses  were  generally  based  on  overly 
 conservative  and  worst  case  conditions.  For  example,  tests  were  performed  in  some  cases  using  UWB  signals  with  characteristics  designed  to  cause  the  greatest  interference  effect.  While  we  recognize  this 
 could  occur,  in  practice  many  UWB  devices  will  have  emission  characteristics  that  are  more  benign  relative  to  particular  receivers.  We  also  note  that  several  of  the  analyses  seek  to  protect 
 radiocommunications  systems  to  levels  below  the  receiver  thermal  noise  floor.  This  is  a  level  of  performance  that  does  not  generally  occur  under  actual  operating  conditions  due  to  the  presence  of  other 

 246  Referencing  the  thermal  noise  to  290  K,  the  receiver  noise  level  for  a  2  MHz  bandwidth  is  110.97  dBm. 
 A  thermal  noise  referenced  to  290  K  is  appropriate  as  the  omnidirectional  antenna  employed  by  the  DARS  receiver  will  encompass  surrounding  terrain. 

 247  Sirius  stated  that  with  a  typical  noise  figure  of  2  dB,  receiver  performance  would  be  degraded  by  3  dB  at 
 150  feet  for  line-  of-  sight  and  25  feet  for  non-  line-  of-  sight.  Sirius  comments  of  4/  25/  01  at  pg.  3.  248 
 Due  to  the  extremely  wide  frequency  separation,  it  is  likely  that  emissions  in  the  DARS  band  would  be  considerably  lower  than  the  Part  15  emission  limits. 
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 sources  of  radio  noise.  Further,  the  fact  that  the  noise  floor  may  increase  does  not  necessarily  indicate  that  harmful  interference  will  occur. 
 171.  Certain  of  the  analyses  applied  only  free  space  attenuation  to  determine  propagation  losses  and  did  not  consider  the  effects  of  intervening  objects.  Some  commenting  parties  sought  to  ensure 
 that  no  interference  would  occur  at  unreasonable  separation  distances,  such  a  having  the  victim  receiver  within  one  meter  of,  or  co-  located  with,  the  UWB  transmitter.  In  some  cases  additional  protection 
 margins  were  added  to  further  ensure  conservative  protection  levels.  We  observe  that  these  various  studies  and  analyses  have  been  useful  in  serving  to  illuminate  the  record  in  this  proceeding.  However,  we 
 do  not  believe  our  regulations  for  controlling  interference  from  UWB  devices  should  be  based  on  a  series  of  worst  case  assumptions.  Instead,  we  find  that  the  various  studies  demonstrate  conclusively  that  UWB 
 devices  can  be  permitted  under  the  proper  set  of  standards  without  causing  harmful  interference  to  other  radio  operations. 

 E.  Emission  Limits 
 1.  General 
 172.  Proposal.  In  order  to  control  harmful  interference  from  UWB  devices,  appropriate  emission  limits  must  be  established.  The  current  Part  15  rules  are  based  on  the  equivalent  of  a  power 

 spectral  density,  i.  e.,  a  field  strength  limit  is  specified  along  with  a  measurement  bandwidth.  These  emission  limits  were  chosen  to  protect  various  classes  of  receivers  from  interference  at  certain  separation 
 distances.  The  radiated  limits  below  1  GHz  are  based  on  measurements  employing  a  quasi-  peak  detector  that  effectively  provides  an  average  reading  with  some  weighting  for  peak  signal  levels.  The  radiated 
 emissions  limits  for  both  intentional  and  unintentional  radiators  above  1  GHz  are  based  on  measurements  using  an  average  detector.  However,  intentional  radiators  also  are  subject  to  a  requirement  that  the  total 
 peak  levels  of  emissions  above  1  GHz  must  be  no  greater  than  20  dB  above  the  average  limits.  249  Higher  peak  levels  could  lead  to  an  increased  risk  of  interference  to  certain  receivers.  For  example,  if  the  pulse 
 repetition  frequency  of  the  UWB  signal  is  much  greater  than  the  bandwidth  of  a  receiver,  the  emission  may  appear  to  be  random  noise,  the  effect  of  which  is  proportional  to  the  average  power  in  the  UWB 
 signal  within  the  receivers  bandwidth.  However,  if  the  PRF  is  much  less  than  the  receivers  bandwidth,  the  UWB  signal  may  appear  to  the  receiver  as  impulsive  noise  and  the  effect  would  be  proportional  to  the 
 peak  power  of  the  UWB  signal.  In  addition,  UWB  devices  spread  their  emissions  over  a  wide  bandwidth  as  compared  to  most  current  intentional  and  unintentional  radiators.  As  a  result,  receivers  that  use  wide 
 bandwidths  are  likely  to  receive  more  total  energy  from  UWB  devices  than  from  most  other  existing  Part  15  devices. 

 173.  In  the  Notice,  the  Commission  concluded  that  it  is  necessary  to  regulate  both  the  peak  and  average  emission  levels  above  1  GHz  and  the  quasi-  peak  emission  levels  below  1  GHz  from  UWB 
 transmitters,  just  as  it  regulates  these  emission  levels  for  most  other  types  of  Part  15  transmission  systems.  The  impact  of  UWB  signals  on  a  receiver  appears  to  depend  on  the  randomness  of  the  UWB 
 signal  and  the  relationship  between  the  pulse  repetition  frequency  (PRF)  of  the  UWB  signal  and  the  bandwidth  of  the  receiver.  250  If  the  UWB  pulses  are  spaced  evenly  in  time  and  each  pulse  is  exactly  the 
 same  (as  in  many  radar  systems),  then  classic  communications  theory  shows  that  the  spectrum  consists  of  narrow  spectral  lines  spaced  at  the  PRF.  The  impact  of  these  signals  on  a  receiver  can  be  modeled  by 
 treating  each  spectral  line  as  a  narrowband  conventional  signal.  This  gives  rise  to  one  possible  way  to  increase  protection  to  GPS  receivers  from  UWB  GPR  and  through-  wall  imaging  devices.  Since  repetitive 

 249  See  47  C.  F.  R.    15.35(  b). 
 250  This  assumes  that  the  UWB  signal  is  far  enough  from  the  receiver  that  it  does  not  overload  the  receiver 
 causing  nonlinear  operation.  The  peak  limits  being  considered  in  this  proceeding  will  ensure  that  receiver  overloading  is  not  a  concern. 
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 identical  pulses  are  often  applicable  to  GPRs  and  through-  wall  imaging  devices,  the  Commission  noted  that  it  might  be  possible  for  designers  to  select  system  parameters  to  avoid  GPS  signal  bands  and  thus 
 avoid  co-  channel  interference.  It  also  may  be  possible  to  space  the  UWB  signals  spectral  lines  in  places  within  the  GPS  band  where  GPS  receivers  are  less  sensitive  to  interference.  Comments  were  requested 
 on  whether  this  technique  is  applicable  to  all  types  of  GPRs  and  through-  wall  imaging  devices  and  the  cost  implication  of  using  a  stable  frequency  reference  to  ensure  the  PRF  creates  a  signal  avoiding  the  GPS 
 bands. 
 174.  For  UWB  communications  systems,  the  emitted  spectrum  depends  on  the  information  being  sent.  If  the  information  is  unchanging,  such  as  a  steady  string  of  zeroes  in  the  case  of  digital 

 information,  the  transmitted  signal  may  become  a  set  of  spectral  lines  that  has  different  interference  potential  than  the  noise-  like  spectrum  that  would  be  produced  under  normal  modulation.  Depending  on 
 exactly  where  these  spectral  lines  are,  the  interference  potential  may  increase.  This  could  be  avoided  by  using  scrambler  technology,  often  used  in  digital  wireline  and  optical  communications  systems,  which 
 prevents  long  strings  of  unchanging  bits.  The  Commission  sought  comment  on  whether  it  should  require  such  scrambler  technology  for  UWB  communications  systems  or,  alternatively,  a  performance 
 requirement  that  would  show  that  the  transmitted  spectrum  remains  noise-  like  in  the  case  of  unchanging  input  data. 

 175.  Comments.  The  comments  generally  indicated  that  the  proposal  to  place  spectral  lines  outside  of  critical  frequency  bands  should  not  be  implemented.  For  example,  as  noted  by  AOPA  doppler 
 shifts  due  to  movements  of  the  GPS  satellites  and  to  movements  of  planes  would  negate  any  ability  to  avoid  the  GPS  band.  251  AOPA  added  that  the  frequency  stability  of  the  circuitry  used  to  generate  the  PRF 
 would  have  to  be  very  stable  raising  cost  concerns.  A.  Peter  Annan  stated  that  this  is  an  impractical  solution  for  GPRs  that  have  low  PRFs  that  make  it  impossible  to  space  the  spectral  lines  far  enough  apart 
 to  avoid  the  GPS  bands.  252  ARRL  noted  that  selecting  PRFs  to  avoid  generating  signals  in  certain  bands  would  add  a  layer  of  regulatory  complexity  that  could  perhaps  be  better  addressed  through  other  means.  253 
 On  the  other  hand,  Aether  Wire  indicates  that  it  may  be  possible  for  its  equipment  to  avoid  the  GPS  L1  and  L2  bands  by  adjusting  the  spaces  between  the  impulse  doublets  and  between  the  impulses  in  each 
 doublet  of  its  transmission,  noting  that  the  oscillation  would  have  sufficient  stability  through  the  use  of  temperature  stabilization.  254 

 176.  With  regard  to  scrambler  technology,  the  comments  supported  requiring  UWB  signals  to  be  noise-  like  in  certain  bands,  particularly  GPS.  AOPA  noted  that  sufficient  dithering  or  scrambling  of 
 the  interference  signal  spectral  lines  in  the  instantaneous  time  or  frequency  domains  would  decrease  the  probability  of  harmful  interference  but  could  increase  aggregate  interference.  255  Aether  Wire  stated  that  a 
 UWB  system  that  lacks  coding  for  channelization  is  severely  limited  in  its  capabilities  and  that  such  a  system  it  the  only  one  for  which  scrambler  technology  is  applicable.  256  It  added  that  a  performance 
 requirement  that  shows  that  the  transmitted  spectrum  remains  noise-  like  in  the  case  of  unchanging  input  data  is  appropriate. 

 177.  Discussion.  We  have  come  to  the  conclusion  that  there  is  no  need  to  establish  design  criteria  for  UWB  systems,  such  as  specifying  where  spectral  lines  may  be  placed  or  requiring  the 
 251  AOPA  comments  at  pg.  13. 
 252  A.  Peter  Anan  comments  at  pg.  4. 
 253  ARRL  comments  at  pg.  14. 
 254  Aether  Wire  comments  at  pg.  11. 
 255  AOPA  comments  at  pg.  13. 
 256  Aether  Wire  comments  at  pg.  12. 
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 application  of  scrambler  technology.  Rather,  we  believe  that  we  should  specify  only  the  emission  limits  that  are  necessary  to  prevent  interference  to  the  authorized  radio  services.  It  will  be  up  to  the 
 manufacturers  of  UWB  devices  to  determine  how  they  will  comply  with  these  standards.  A  discussion  of  the  emission  levels  we  are  adopting  follows.  As  will  be  noted,  we  are  adopting  a  requirement  to  limit  the 
 power  level  of  the  spectral  lines  that  appear  in  the  GPS  frequency  bands. 
 2.  Average  and  Quasi-  peak  Emission  Levels 
 178.  Proposal.  The  Commission  stated  in  the  Notice  that  the  Part  15  general  emission  limits  257  have  a  long  and  successful  history  of  controlling  interference  to  other  radio  operations.  However,  the 

 general  emission  limits  were  never  designed  to  protect  against  all  possibilities  of  harmful  interference.  Rather,  these  limits  were  designed  to  protect  neighbors  from  causing  interference  to  each  other.  258  These 
 limits  were  designed  as  a  reasonable  compromise  to  protect  the  authorized  radio  services  from  receiving  harmful  interference  without  requiring  an  analysis  of  the  individual  needs  of  every  type  of  receiver  design 
 used  in  every  radio  service.  The  Commission  reiterated  that  it  remains  committed  to  protecting  the  authorized  radio  services  from  receiving  harmful  interference  from  Part  15  devices,  adding  that  it  was 
 especially  concerned  about  protecting  radio  services  used  for  safety-  of-  life  applications,  such  as  GPS,  from  such  interference.  Accordingly,  the  Commission  indicated  in  the  Notice  that  the  general  emission 
 limits  contained  in  47  C.  F.  R.  Section  15.209  appear  appropriate  for  UWB  operations.  These  emission  limits  are  already  based  on  a  spectral  power  density,  measuring  signal  level  per  unit  bandwidth.  259  It  also 
 proposed  that  additional  protection  be  provided  below  approximately  2  GHz  for  emissions  from  UWB  devices.  For  emissions  from  UWB  devices  other  than  GPRs  and,  possibly,  through-  wall  imaging 
 systems,  it  proposed  that  emissions  that  appear  below  approximately  2  GHz  be  attenuated  by  at  least  12  dB  below  the  general  emission  limits.  This  attenuation  below  the  general  emission  levels  would  provide 
 additional  protection  to  the  congested  spectrum  below  2  GHz  without  affecting  the  viability  of  UWB  operations.  Comments  were  requested  on  whether  additional  attenuation  below  2  GHz  is  necessary. 
 Comments  were  also  sought  on  whether  the  proposed  reduction  in  the  emission  levels  should  apply  to  all  emissions  below  2  GHz  or  only  to  emissions  below  2  GHz  that  fall  within  the  restricted  bands  shown  in 
 47  C.  F.  R.    15.205.  Comments  also  were  requested  on  whether  UWB  devices  other  than  GPRs,  and  possibly  through-  wall  imaging  systems,  should  be  permitted  to  operate  below  2  GHz  provided  they 
 comply  with  these  reduced  emission  levels.  Finally,  the  Commission  indicated  that  the  emission  limits  that  were  proposed  in  the  Notice  were  a  reasonable  starting  point  for  establishing  standards.  As 
 equipment  continues  to  be  developed  and  additional  experience  is  gained  with  this  equipment,  future  changes  to  the  standards  would  be  considered. 

 179.  Comments/  Discussion.  260  A  considerable  number  of  comments  were  filed  concerning  the  levels  of  emissions  that  should  be  permitted  for  UWB  transmitters.  Most  of  the  comments  supported  the 
 continued  application  of  quasi-  peak  limits  on  radiated  emissions  below  1000  MHz  and  of  average  and 

 257  See  47  C.  F.  R.    15.109(  a)  and  15.209. 
 258  While  it  is  possible  to  establish  emission  limits  that  protect  a  user  from  his  own  interference  at  separation 
 distances  on  the  order  of  one  meter,  such  limits  would  significantly  add  to  the  cost  of  all  Part  15  devices,  including  computers,  cordless  telephones  and  receivers. 

 259  Emissions  below  1  GHz  are  measured  using  a  CISPR  quasi-  peak  detector  with  a  resolution  bandwidth  of 
 120  kHz  +  20  kHz.  Emissions  above  1  GHz  are  measured  using  a  1  MHz  resolution  bandwidth.  See  47  C.  F.  R.    15.35. 

 260  Some  of  the  comments  continued  to  propose  that  UWB  devices  be  subject  to  the  same  emission  limits  as 
 those  applied  to  Class  A  digital  devices.  The  Commission  considered  this  issue  in  the  Notice  and  declined  to  propose  it.  We  find  no  new  information  in  the  comments  that  would  cause  us  to  reconsider.  See  Notice,  supra,  at 

 para.  40. 
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 peak  limits  on  radiated  emissions  above  1000  MHz.  261  NTIA,  however,  requested  that  average  and  peak  emission  limits  apply  to  all  emissions  above  960  MHz.  Some  commenting  parties  requested  that  we 
 implement  limits  on  spectral  power  density.  262  However,  the  quasi-  peak  and  average  limits  currently  contained  in  the  Part  15  rules  already  are  based  on  spectral  power  densities.  For  example,  the  quasi-  peak 
 limits  for  emissions  between  30  MHz  and  1000  MHz  are  based  on  the  emissions  that  appear  in  a  120  kHz  +  20  kHz  bandwidth.  The  emission  limits  above  1000  MHz  are  based  on  the  emissions  that  appear  in  a  1 
 MHz  bandwidth.  263 
 180.  There  was  no  concurrence  in  the  comments  with  regard  to  the  emission  limits  that  should  be  adopted.  The  ARRL  stated  that  the  Part  15  general  emission  limits  have  not  been  adequate  to  protect 

 all  amateur  operations;  however,  it  could,  with  some  reluctance,  accept  the  idea  that  permitting  UWB  operation  at  those  levels  is  not  much  different  in  kind  from  the  types  of  operation  permitted  under  the  Part 
 15  rules.  264  It  added  that  the  impact  on  amateur  receivers  from  UWB  signals  that  are  noise-  like  would  be  determined  by  the  average  power  present  in  the  victim  receiver  bandwidth  whereas  for  UWB  signals  with 
 low  PRFs,  the  noise  may  appear  as  impulse  and/  or  multiple  discrete  signals  within  the  receiver  passband  where  the  peak  limit  would  be  more  important.  265  Lucent  also  agreed  that  the  proposed  peak  and  average 
 limits  were  sufficient  for  interference  protection  provided  average  measurements  are  clarified.  266  On  the  other  hand,  parties  such  as  XM  requested  that  the  emission  levels  in  the  satellite  DARS  band  be  reduced 
 to  an  EIRP  of  100  dBW,  about  29  dB  below  the  existing  Part  15  emission  limit.  267  Parties  such  as  Siemens  Automotive  and  others  want  the  Part  15  emission  levels  increased  at  the  higher  frequencies.  268 

 181.  With  the  exception  of  GPR  manufacturers,  a  few  comments  requested  increases  in  the  Part  15  emission  levels  for  UWB  devices.  MSSI  wished  to  operate  with  a  one  watt  peak  output  into  a  6 
 dBi  antenna.  269  While  MSSI  equated  its  UWB  operation  to  the  regulations  for  spread  spectrum  operation,  the  current  rules  designate  specific  frequency  bands  for  spread  spectrum  operation.  270  Implementation  of 
 this  same  power  level  for  operation  in  other  frequency  bands  was  not  supported  by  the  earlier  test  data  or  comments.  Bosch,  Saab,  Siemens  and  Valeo  requested  that  the  higher  frequency  bands  be  permitted 
 increased  signal  levels  due  to  increased  attenuation.  271  We  agree  that  higher  attenuation  applies  to  RF  emissions  as  frequency  increases  and  that  this  may  prove  to  be  an  acceptable  approach  to  modifying  the 
 Part  15  emission  limits.  However,  we  do  not  believe  that  initial  UWB  operations  should  begin  with  a  power  increase. 

 261  See,  for  example,  the  comments  of  AOPA  at  pg.  12,  Lucent  at  pg.  1,  and  NBAA  at  pg.  13. 
 262  See,  for  example,  the  comments  of  AT&  T  at  pg.  6  and  Cisco  at  pg.  6-  9. 
 263  See  47  C.  F.  R.    15.  35(  b). 
 264  ARRL  comments  at  pg.  12. 
 265  ARRL  comments  at  pg.  14. 
 266  Lucent  comments  at  pg.  1. 
 267  XM  comments  at  pg.  A6  and  reply  comments  at  pg.  8. 
 268  See,  for  example,  Bosch  reply  comments  at  pg.  3,  SME  comments  at  pg.  3,  Siemens  comments  at  pg.  2,  and 
 MSSI  reply  comments  at  pg.  2.  269 
 MSSI  reply  comments  at  pg.  2.  Also,  MSSI  comments  of  3/  22/  01  at  pg.  4.  270 
 See  47  C.  F.  R.    15.  247.  The  spread  spectrum  frequency  bands  are  902-  928  MHz,  2400-  2483.5  MHz,  and  5725-  5750  MHz. 

 271  Bosch  reply  comments  at  pg.  4.  Saab  comments  at  pg.  3.  Siemens  comments  at  pg.  2.  Valeo  comments  at 
 pg.  5-  6.  Valeo  actually  requested  a  variable  limit  where  the  emission  would  be  at  thermal  noise  at  10  meters  using  free  space,  a  0  dBi  antenna  and  a  3  dB  receiver  noise  figure. 
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 182.  As  noted  by  TDC,  the  issue  of  what  constitutes  reasonable  levels  of  emissions  outside  of  defined  bands  confronts  the  Commission  every  time  a  new  licensed  or  unlicensed  service  is  proposed.  272 
 However,  several  tests  and  analyses,  discussed  earlier,  have  been  performed  in  this  proceeding  that  permit  us  to  determine  the  appropriate  emission  limits.  As  noted  earlier,  there  were  only  a  few  instances  where 
 UWB  systems  operating  at  the  limits  in  47  C.  F.  R.    15.209  demonstrated  a  clear  potential  to  cause  harmful  interference  to  the  authorized  radio  services.  In  most  of  these  instances,  the  UWB  transmitter 
 and  the  victim  receiver  were  required  to  be  in  extremely  close  proximity  to  each  other  before  harmful  interference  could  occur. 

 183.  As  discussed  earlier,  the  interference  analyses  performed  by  NTIA  and  others  allowed  us  to  determine  the  emission  limits  that  should  be  applied  to  UWB  devices  operating  under  various  worst 
 case  conditions.  Based  on  the  limited  information  in  the  record  and  our  lack  of  operation  experience  with  UWB  devices,  we  believe  it  best  to  proceed  with  an  abundance  of  caution  in  establishing  emission  limits. 
 The  limits  we  are  adopting  were  coordinated  with  NTIA,  as  well  as  with  several  other  U.  S.  Government  agencies.  273  These  limits  are  an  appropriate  first  step  in  introducing  UWB  devices.  The  following  table 
 specifies  the  average  emission  limits,  in  terms  of  dBm  EIRP  as  measured  with  a  one  megahertz  resolution  bandwidth,  that  we  are  implementing  for  UWB  operation. 

 Table  8  Average  Emission  Limits  Applicable  to  UWB  Operation 
 Frequency  Band  (MHz)  Imaging  below  960 
 MHz 
 Imaging,  Mid-Frequency  Imaging,  High 
 frequency 
 Indoor  applications  Hand  held,  including 
 outdoor 
 Vehicular  radar 

 0.009-  960  15.209  15.209  15.209  15.209  15.209  15.209  960-  1610  -65.3  -53.3  -65.3  -75.3  -75.3  -75.3 
 1610-  1990  -53.3  -51.3  -53.3  -53.3  -63.3  -61.3  1990-  3100  -51.3  -41.3  -51.3  -51.3  -61.3  -61.3 
 3100-  10600  -51.3  -41.3  -41.3  -41.3  -41.3  -61.3  10600-  22000  -51.3  -51.3  -51.3  -51.3  -61.3  -61.3 
 22000-  29000  -51.3  -51.3  -51.3  -51.3  -61.3  -41.3  Above  29000  -51.3  -51.3  -51.3  -51.3  -61.3  -51.3 

 184.  Mid-  frequency  imaging,  consisting  of  through-  wall  imaging  systems  and  surveillance  systems,  must  operate  with  the  10  dB  bandwidth  within  the  frequency  band  1990-  10,600  MHz.  High 
 frequency  imaging  systems,  equipment  that  will  be  operated  exclusively  indoors,  and  hand  held  UWB  devices  that  may  operate  anywhere,  including  outdoors  and  for  peer-  to-  peer  applications,  must  operate 
 with  the  10  dB  bandwidth  within  the  frequency  band  3100-  10,  600  MHz.  All  other  imaging  systems  must  operate  with  the  10  dB  bandwidth  below  960  MHz.  Vehicular  radar  systems  must  operate  with  the 
 -10  dB  bandwidth  within  the  frequency  band  22-  29  GHz  and  with  a  carrier  frequency  greater  than  24.075  GHz.  To  further  ensure  that  the  operation  of  these  UWB  devices  does  not  result  in  harmful  interference, 
 we  also  are  requiring  coordination  with  NTIA  through  the  Commission  of  the  imaging  systems.  The  operators  of  these  devices  will  be  required  to  provide  us  with  their  address,  the  characteristics  of  the 
 UWB  device,  and  a  detailed  record  of  the  areas  in  which  the  equipment  will  be  operated.  The  information  submitted  to  the  Commission  will  be  forwarded  to  NTIA  for  notification  purposes.  The  operators  of 
 UWB  imaging  systems  must  complete  this  coordination  and  authorization  procedure  before  initial  operation  of  the  equipment  in  a  particular  area.  As  noted  previously,  in  emergency  situations  a 

 272  TDC  comments  at  pg.  19. 
 273  See  letter  of  February  13,  2002,  from  William  Hatch,  supra. 
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 notification  process  may  be  used  in  lieu  of  coordination.  274  Further,  depending  on  the  specific  location  it  may  be  necessary  for  the  operators  to  coordinate  day-  to-  day  operations  with  nearby  radio  stations  within 
 their  operating  area.  The  manufacturers  of  these  devices  will  be  required  to  inform  the  users  of  the  equipment  of  these  requirements.  Because  of  the  tighter  emission  limits  being  employed,  coordination  is 
 not  being  required  for  indoor  equipment,  hand  held  devices,  or  vehicular  radar  systems. 
 3.  Imaging  Systems  Including  GPRs 
 185.  As  noted  throughout  this  Report  and  Order,  we  are  taking  a  cautious  approach  to  the  standards  for  UWB  devices.  One  method  of  reducing  interference  potential  is  to  restrict  the  applications 

 for  using  UWB  devices  and  the  locations  where  UWB  devices  may  be  operated.  These  devices  will  have  a  low  proliferation  and  would  be  used  infrequently.  Further,  the  primary  energy  from  a  GPR  is  directed 
 into,  and  absorbed  by,  the  ground.  In  addition,  the  energy  radiated  by  the  GPR  is  at  a  low  elevation  where  it  should  attenuate  rapidly.  275  To  ensure  that  the  proliferation  remains  low,  we  are  restricting  the  parties 
 that  may  operate  GPRs  to  law  enforcement,  fire  and  emergency  rescue  organizations,  to  scientific  research  institutes,  to  commercial  mining  companies,  and  to  construction  companies.  As  used  in  this 
 Order,  law  enforcement,  fire  and  emergency  rescue  organizations  refers  to  parties  eligible  to  obtain  a  license  from  the  FCC  under  the  eligibility  requirements  specified  in  Section  90.20(  a)(  1)  of  this  chapter. 
 All  users  of  GPRs  must  be  eligible  for  licensing  under  Part  90  of  our  rules,  and  these  users  must  coordinate  with  the  FCC,  which  in  turn  will  coordinate  with  NTIA,  before  operation. 

 186.  Peter  Annan  stated  that  GPRs  need  special  consideration  on  emission  limits  with  more  power  needed  at  lower  frequencies,  particularly  for  operation  below  250  MHz.  276  He  requested  that  GPRs 
 be  permitted  to  operate  at  an  average  power  limit  of  500  mW  below  50  MHz  and  20  mW  above  250  MHz  with  a  logarithmic  progression  between  these  power  levels  between  50  MHz  and  250  MHz.  GSSI  and 
 Sensors  &  Software,  in  extremely  late  filed  comments,  requested  that  GPRs  operating  with  PRFs  lower  than  500  MHz  and  at  frequencies  below  500  MHz  be  permitted  to  exceed  the  47  C.  F.  R.    15.209  limits, 
 up  to  a  maximum  level  of  95  dBuV/  m  below  30  MHz.  277  These  companies  did  not  indicate  how  or  at  what  distance  the  revised  emission  limit  should  be  measured,  but  we  believe,  based  on  their  October  2, 
 2001,  meeting  with  the  staff  of  our  Office  of  Engineering  and  Technology,  that  they  desired  these  limits  to  be  based  on  an  average  measurement. 

 187.  Subsequent  to  the  October  10,  2001,  filing  by  GSSI  and  Sensors  and  Software,  a  late  filed  comment  was  submitted  on  October  16,  2001,  by  Mr.  Steven  Koppenjan  et  al,  identifying  themselves  as 
 the  general  chairs  of  the  6  th  ,  7  th  ,  8  th  and  9  th  International  Conferences  on  Ground  Penetrating  Radar.  Mr.  Koppenjan  et  al  indicated  that  new  GPR  products  are  being  developed  that  will  comply  with  the  limits 
 proposed  in  the  Notice.  They  add  that  pulse  compression  schemes  can  provide  both  low  peak-  to-  average 

 274  We  note  that  US  Government  radio  stations  may  be  operated  without  coordination  under  emergency 
 circumstances.  See  Manual  of  Regulations  and  Procedures  for  Federal  Radio  Frequency  Management,  U.  S.  Department  of  Commerce,  National  Telecommunications  and  Information  Administration,  January  2000,  at  Section 

 7.3.1.  We  also  note  that  no  similar  provision  exists  that  would  permit  non-  Government  operation  absent  appropriate  coordination.  However,  we  are  implementing  a  procedure  similar  to  that  contained  in  47  C.  F.  R.  Section  2.405(  a)-(  e) 
 to  facilitate  the  emergency  operation  of  UWB  imaging  devices.  275 
 We  expect  that  the  emissions  would  attenuate  with  distance  based  on  the  cube  of  the  inverse  distance,  not  the  square  as  employed  with  free  space  propagation. 

 276  A.  Peter  Annan  comments  at  pg.  3-  5. 
 277  GSSI  and  Sensors  and  Software  comments  of  October  10,  2001.  The  maximum  limit  was  expressed  as  20 
 log  (500MHz/  testing  frequency  in  MHz)  dBuV/  m.  At,  say,  20  MHz,  the  testing  frequency  is  9  kHz  resulting  in  a  signal  level  of  94.  9  dBuV/  m  or  55,  600  uV/  m.  The  existing  limit  at  20  MHz  is  30  uV/  m,  as  measured  at  30  meters 

 with  a  quasi-  peak  detector,  or  29.  5  dBuV/  m. 
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 power  ratios  in  the  time  domain  and  low  spectral  power  density  in  compliance  with  the  proposals. 
 188.  Sufficient  notice  was  not  provided  to  the  other  parties  interested  in  this  proceeding  to  permit  us  to  address  a  relaxation  to  the  emission  limits  below  500  MHz.  In  addition,  the  request  to  allow 

 certain  GPR  devices  to  operate  at  higher  emissions  levels  was  filed  very  late,  which  did  not  afford  an  opportunity  for  analysis  by  other  parties.  We  also  note  that  GSSI  did  not  provided  any  interference 
 analysis  to  support  its  proposals,  other  than  a  statement  that  existing  GPRs  have  operated  benignly  with  these  emission  characteristics  for  30  years.  It  appears  that  the  basis  of  the  proposals  from  GSSI  and  from 
 Sensors  &  Software  is  to  accommodate  existing  equipment  designs.  278  It  also  appears,  based  on  the  comment  from  Mr.  Koppenjan  et  al,  that  it  may  be  possible  for  GPRs  to  be  designed  to  comply  with  the 
 radiated  emission  limits  proposed  in  the  Notice.  Thus,  we  are  not  persuaded  that  higher  emission  levels  are  prudent  especially  in  the  early  stages  of  UWB  standards  development.  Such  higher  limits  could 
 overpower  the  front  end  of  a  nearby  receiver  or  result  in  harmful  interference  to  nearby  television  broadcast  reception. 

 189.  In  contrast  to  GPRs,  other  types  of  imaging  systems  may  be  used  for  a  variety  of  applications  where  the  energy  is  aimed  horizontally  along  the  earth.  We  anticipate  that  the  walls, 
 buildings  or  other  objects  against  which  the  imaging  system  may  be  placed  may  absorb  most  of  the  energy.  279  However,  we  recognize  that  with  imaging  systems  other  than  GPRs  there  is  an  increased  risk 
 that  some  of  the  energy  would  not  be  absorbed  and  could  be  radiated  in  the  direction  of  authorized  radio  services.  Thus,  as  a  cautious  approach  we  are  restricting  the  use  of  imaging  systems.  Wall  imaging 
 systems  may  be  employed  only  by  law  enforcement,  fire  and  emergency  rescue  organizations,  by  scientific  research  institutes,  by  commercial  mining  companies,  and  by  construction  companies.  Only  law 
 enforcement,  fire  or  emergency  rescue  organizations  may  use  through-  wall  imaging  systems.  Further,  the  operators  of  through-  wall  and  wall  imaging  systems  must  be  parties  that  are  eligible  to  obtain  licensing 
 under  the  provisions  in  Part  90  of  our  rules.  Finally,  medical  imaging  systems  may  be  used  only  at  the  direction  of,  or  under  the  supervision  of,  a  licensed  health  care  practitioner.  This  will  allow  the 
 introduction  of  the  compelling  uses  for  UWB  imaging  systems  cited  by  the  commenters,  such  as  for  hostage  rescue,  law  enforcement,  inspection  of  building  walls  and  foundations,  and  detecting  objects 
 inside  walls  when  performing  construction.  At  the  same  time,  by  limiting  the  applications  for  UWB  imaging  we  will  minimize  the  risk  of  interference  by  controlling  the  proliferation  of  these  devices.  The 
 applications  for  UWB  imaging  systems  will  be  controlled  through  our  equipment  authorization  program.  In  addition,  the  grantees  of  equipment  authorization  will  be  responsible  for  ensuring  that  the  marketing 
 and  distribution  of  these  products  is  consistent  with  the  restrictions  on  use. 
 4.  Other  Applications 
 190.  While  we  believe  that  some  of  the  interference  levels  characterized  by  the  commenters  may  not  represent  real-  world  situations,  we  agree  that  the  initial  UWB  regulations  should  be  implemented 

 cautiously.  Accordingly,  we  are  implementing  a  reduction  to  the  Part  15  general  emission  levels  over  certain  frequency  bands  to  ensure  that  our  introduction  of  UWB  devices  causes  the  least  possible  impact 
 to  the  authorized  radio  services.  We  investigated  different  standards  for  UWB  devices  depending  on  whether  they  are  operated  outdoors  or  indoors.  We  believe  that  the  combined  operating  conditions  and 
 emissions  standards  will  prevent  harmful  interference.  The  operation  of  UWB  devices  at  the  EIRP  levels 
 278  The  only  UWB  GPRs  that  have  been  certified  by  the  Commission  are  those  produced  by  U.  S.  Radar.  U.  S. 
 Radar  received  a  waiver  from  the  Commission,  subsequent  to  extensive  coordinated  with  NTIA,  to  permit  the  marketing  and  use  of  its  product.  The  marketing  or  use  of  any  GPR  that  has  not  been  certified,  except  under  the 

 conditions  specified  in  47  C.  F.  R.    15.  211,  is  in  violation  of  47  U.  S.  C.  301  and  302  and  is  subject  to  the  penalties  described  in  47  U.  S.  C.  501-  510. 
 279  Similarly,  we  believe  that  medical  imaging  systems  would  be  used  indoors  such  that  intervening  walls 
 would  attenuate  the  emissions. 
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 being  adopted  in  this  proceeding  should  provide  sufficient  attenuation  to  protect  authorized  services  from  harmful  interference  from  UWB  systems  operating  nearby  or  in  elevated  locations,  such  as  inside 
 buildings. 
 191.  With  regard  to  GPS,  we  are  particularly  concerned  about  protecting  E-  911  applications.  As  noted  above,  GPS  systems  can  experience  harmful  interference  if  they  are  within  a  few  meters  of  a 

 UWB  system  operating  at  the  general  limits  in  47  C.  F.  R.    15.209.  The  emission  limits  being  adopted  in  this  proceeding  within  the  GPS  frequency  bands,  ranging  from  12  to  34  dB  below  the  Part  15  general 
 limits,  were  found  to  be  more  than  sufficient  to  protect  GPS  from  harmful  interference.  Further,  we  note  that  GPS  operates  in  the  same  frequency  region  as  DME  transponders,  the  ARSR-  4,  and  SARSAT 
 systems.  280  We  also  note  that  the  emission  limits  we  are  applying  to  the  GPS  bands  are  more  than  sufficient  to  prevent  harmful  interference  to  all  Government  systems  operating  in  the  960-  1610  MHz 
 band. 
 192.  We  also  concluded  from  our  analysis  of  the  Qualcomm  submission  that  it  could  be  advantageous  to  provide  additional  protection  to  PCS  operation  in  the  1850-  1990  MHz  band  due  to  its 

 potential  use  in  E-  911  applications.  The  12  dB  of  attenuation  below  the  Part  15  general  emission  limits  appears  more  than  sufficient  to  provide  this  protection,  as  described  in  our  discussion  of  the  Qualcomm 
 analyses.  We  do  not  believe  that  additional  attenuation  is  needed  for  UWB  emissions  falling  in  the  Cellular  Radiotelephone  Service  bands  at  824-  849  MHz  and  869-  894  MHz  bands.  In  the  first  place,  the 
 Part  15  general  emission  limits  for  the  cellular  frequency  band,  unlike  those  for  the  PCS  band,  are  expressed  as  a  quasi-  peak  limit.  The  modulation  employed  by  UWB  devices  will  tend  to  be  measured  in 
 the  cellular  band  as  a  peak  spectral  power  density  whereas  the  cellular  receiver  will  respond  to  the  average  signal  level  from  the  UWB  transmitter.  This  should  provide  sufficient  additional  protection  to 
 cellular  reception.  Second,  only  imaging  systems  will  operate  at  the  low  frequency  employed  for  cellular  operation.  Third,  the  emissions  from  cellular  transmitters  that  fall  within  the  band  used  by  the  mobile 
 receiver  are  permitted  at  a  level  of  80  dBm,  as  measured  at  the  antenna  connector.  281  This  is  the  level  of  interference  that  a  cellular  mobile  transmitter  may  cause  to  its  own  receiver.  This  also  is  the  level  that 
 would  be  produced  by  a  UWB  transmitter,  operating  at  the  Part  15  general  emission  limits,  at  a  separation  distance  of  about  4  meters  using  free  space  attenuation  with  no  intervening  objects.  Thus,  the  separation 
 distance  between  a  UWB  transmitter  operating  at  the  general  emission  limits  and  a  cellular  receiver  is  about  the  same  as  that  of  a  UWB  transmitter  operating  at  12  dB  below  the  general  emission  limits  and  a 
 PCS  receiver.  Accordingly,  we  find  that  no  additional  attenuation  in  the  cellular  band  is  required. 
 193.  Based  on  the  above,  we  are  applying  a  12  dB  reduction  below  the  general  emission  limits  over  the  frequency  range  1610  MHz  to  1990  MHz.  282  We  also  have  applied  a  10  dB  reduction  below  the 

 general  emission  limits  for  emissions  between  1990  and  3100  MHz  to  ensure  protection  from  harmful  interference  to  the  U.  S.  Government  operations  within  this  band  as  well  as  the  operation  of  DARS  and 
 other  communications  systems  operating  within  this  band. 
 194.  One  of  the  largest  potential  outdoor  uses  of  UWB  technology  is  vehicular  radar.  However,  we  do  not  believe  that  the  proliferation  of  such  devices  will  result  in  increased  interference 

 280  GPS  operation  occurs  at  1164-  1215  MHz  for  the  L5  band,  1215-  1240  MHz  for  the  L2  band,  and  1559-  1610 
 MHz  for  the  L1  band.  DME  transponders  operate  at  1025-  1150  MHz;  the  ARSR-  4  operates  at  1240-  1370  MHz;  and  SARSAT  operates  at  1544-  1545  MHz. 

 281  47  C.  F.  R.    22.917(  f).  This  standard  originally  was  established  by  the  cellular  industry,  working  through 
 the  Electronics  Industry  Association,  and  was  published  in  the  Commissions  OST  Bulletin  No.  53,  Cellular  System  Mobile  Station    Land  Station  Compatibility  Specification,  April  1981  at  Section  2.2.3.1.1. 

 282  As  discussed  elsewhere  in  this  Order,  an  additional  8  dB  of  suppression  has  been  applied  to  vehicular  radar 
 systems  and  an  additional  10  dB  has  been  applied  to  hand  held  devices  at  the  request  of  NTIA. 
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 concerns  at  the  emission  levels  and  frequency  range  being  adopted.  We  are  requiring  that  the  -10  dB  bandwidth  be  between  22-  29  GHz  and  that  the  center  frequency  be  greater  than  24.075  GHz.  283  In 
 addition,  there  is  a  high  probability  that  other  intervening  objects,  e.  g.,  other  vehicles,  will  cause  the  emissions  to  rapidly  attenuate,  especially  at  the  higher  frequencies.  Emissions  far  removed  from  the 
 center  frequency,  e.  g.,  emissions  appearing  below  10  GHz,  should  appear  similar  to  spurious  emissions  from  other  types  of  Part  15  devices.  284  Because  we  are  requiring  the  lower  frequency  emissions  to  be 
 attenuated  below  the  Part  15  general  emission  limits,  the  interference  potential  from  vehicular  radar  systems  to  lower  frequency  radio  systems  will  be  less  than  the  interference  potential  of  conventional  Part 
 15  devices. 
 195.  Our  primary  interference  concern  with  vehicular  radar  systems  is  cumulative  interference  to  passive  sensing  systems  operating  in  the  23.6  to  24.0  GHz  band  on  low  earth  orbiting  satellites, 

 including  meteorological  satellites.  285  NTIA  indicated  that  it  performed  an  analysis  of  the  potential  interference  to  EESS  passive  satellite  receivers.  286  NTIA  states  that  a  potential  for  harmful  interference  to 
 EESS  receivers  would  exist  if  emissions  below  24.0  GHz  were  permitted  at  the  Part  15  general  emission  limits.  NTIA  based  its  analysis  on  a  22  to  23  dB  antenna  discrimination  at  elevation  angles  above  30 
 degrees  above  the  horizon.  It  concluded  that  the  emissions  from  vehicular  radar  systems  in  the  23.6-  24.0  GHz  band  must  be  35  dB  below  the  Part  15  general  emission  limits  at  elevation  angles  greater  than  30 
 degrees  above  the  horizon.  287  NTIA  indicated  that  an  attenuation  of  25  dB  at  elevation  angles  of  greater  than  30  degrees  could  be  achieved  at  the  present  time.  NTIA  indicated  that  the  radars  would  be  placed  on 
 transportation  vehicles  over  a  period  of  time  and  agreed  to  allowing  a  phased-  in  approach  to  obtain  the  additional  attenuation.  It  agreed  to  permit  UWB  vehicular  radar  systems  provided  these  systems  attenuate 
 emissions  appearing  within  the  23.6-  24.  0  GHz  band  at  greater  than  30  dB  elevation  above  the  horizontal  plane  by  the  following  amounts  below  the  Part  15  general  emission  limits:  25  dB  by  January  1,  2005;  30 
 dB  by  January  1,  2010,  and  35  dB  by  January  1,  2014. 
 196.  We  believe  that  the  analysis  performed  by  NTIA  may  be  overly  conservative.  288  However,  to  ensure  that  the  cumulative  impact  of  the  potentially  tens  of  thousands  of  transportation 

 vehicles  employing  these  radar  devices  does  not  result  in  harmful  interference  to  the  passive  satellite  receivers  we  are  requiring  that  the  emissions  38  degrees  or  higher  above  the  horizontal  plane  in  the  23.6- 
 24.0  GHz  band  from  properly  installed  vehicular  radar  systems  be  attenuated  by  more  than  25  dB  below 
 283  Part  15  radar  systems  currently  are  permitted  to  operate  in  the  24.075-  24.  175  GHz  band.  See  47  C.  F.  R.   
 15.  245.  284 
 The  UWB  antenna  will  act  as  a  band-  pass  filter.  Emissions  appearing,  say,  20  GHz  below  a  transmitter  operating  with  a  center  frequency  above  24  GHz  will  be  a  random  collection  of  cabinet  radiation  and  antenna 

 resonant  frequencies.  285 
 See  47  C.  F.  R.    2.106.  286 
 See  letter  of  February  13,  2002,  from  William  Hatch,  supra..  287 
 We  note  that  it  does  not  make  a  difference  as  to  whether  this  attenuation  is  achieved  through  antenna  directivity,  the  suppression  of  emissions  below  24  GHz  or  some  other  method. 

 288  For  example,  NTIA  did  not  provide  any  attenuation  of  the  radiated  emissions  due  to  foliage,  terrain, 
 buildings,  or  other  vehicles  as  would  be  expected  at  the  low  elevation  angles  involved.  NTIA  also  assumed  that  each  vehicle  would  have  four  radar  transmitters  directed  towards  the  satellite,  resulting  in  a  6  dB  increase  to  the 

 received  level,  with  the  emissions  from  these  transmitters  attenuated,  due  to  antenna  directivity,  by  21.9  dB  at  an  angle  of  33.  2  degrees,  the  lowest  LOS  elevation  angle  used  in  NTIAs  analyses.  NTIA  concluded  in  its  calculations 
 that  an  additional  10  dB  of  attenuation  is  necessary,  resulting  in  an  antenna  directivity  of  31.9  dB  at  33.2  degrees  above  the  horizontal  plane,  of  33.  2  dB  at  35.  2  degrees,  or  of  40  dB  at  90  degrees,  depending  on  which  of  its  four 
 analysis  NTIA  employed.  However,  NTIA  then  required  that  the  antenna  directivity  be  increased  to  an  even  tighter  margin  of  35  dB  at  an  elevation  of  30  degrees.  NTIA  did  not  provide  any  justification  for  its  additional  protection 
 margin. 
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 the  Part  15  general  emission  limit.  The  attenuation  can  be  due  to  antenna  directionality,  a  lowered  transmitter  power  level  or  whatever  combination  produces  this  desired  result.  For  equipment  authorized, 
 manufactured  or  imported  on  or  after  January  1,  2005,  this  attenuation  below  the  Part  15  general  emission  limit  must  be  increased  to  25  dB  at  30  degrees  or  greater  elevation.  This  attenuation  at  elevations  greater 
 than  30  degrees  shall  increase  to  30  dB  by  January  1,  2010,  and  to  35  dB  by  January  1,  2014.  We  intend  to  review  these  standards  as  additional  experience  is  gained.  In  addition,  we  note  that  this  limit  on  the 
 emissions  from  a  vehicular  radar  in  the  vertical  direction  results  in  the  emissions  radiated  towards  the  passive  satellite  sensors  to  appear  as  spurious  emissions.  Thus,  we  are  exempting  Part  15  UWB  devices 
 from  the  provisions  contained  in  US  Footnote  246  to  the  frequency  allocation  table.  289 
 197.  We  were  able  to  reduce  considerably  the  potential  for  harmful  interference  from  UWB  systems  by  limiting  outdoor  devices  to  imaging  and  vehicular  radar  applications.  These  devices  will  likely 

 use  directional  antennas  that  reduce  the  probability  that  a  UWB  transmitter  will  be  pointed  at  any  particular  victim  receiver.  However,  the  UWB  proponents  indicated  a  desire  to  provide  many  other  types 
 of  UWB  systems,  especially  communications  systems.  These  systems  likely  would  operate  at  high  PRFs  with  omnidirectional  antennas  in  the  lower  frequency  bands,  e.  g.,  with  a  center  frequency  lower  than  5  to 
 7  GHz.  Further,  manufacturers  indicated  their  desire  to  permit  these  operations  with  minimal  restrictions  on  who  may  use  the  equipment  or  on  licensing.  Indeed,  some  proponents  requested  that  we  establish  an 
 emission  limit  that  permits  general  outdoor  operation. 
 198.  XSI,  in  its  ex  parte  filing  of  October  22,  2001,  among  others,  requested  that  we  prohibit  outdoor  infrastructure  or  establish  lower  emission  limits  to  permit  outdoor  applications.  290  XSI  stated  that 

 it  would  be  willing  to  attenuate  the  emissions  from  its  UWB  communications  systems  to  below  the  Part  15  general  emission  limits  by  12  dB  over  the  band  2  GHz  to  1.6  GHz,  18  dB  below  1.6  GHz,  and  35  dB 
 in  the  GPS  band  with  an  additional  10  dB  in  the  GPS  band  for  spectral  lines.  In  its  ex  parte  filing  of  November  5,  2001,  XSI  suggested  that  the  Commission  require  an  additional  reduction  of  9  to  12  dB  in 
 emissions  below  3.1  GHz  from  peer-  to-  peer  devices  to  provide  the  same  attenuation  that  would  be  provided  indoor  operation  due  to  building  shielding.  291 

 199.  Based  on  our  coordination  with  NTIA  and  other  concerned  U.  S.  Government  agencies,  we  believe  that  limited  outdoors  operation,  including  general  peer-  to-  peer  operations,  can  be  permitted 
 provided  the  emissions  from  the  UWB  devices  within  the  1610-  3100  MHz  band  and  above  10.6  GHz  are  attenuated  by  at  least  10  dB  below  the  emission  levels  being  permitted  for  indoor  applications.  However, 
 we  remain  concerned  that  permitting  UWB  devices  to  be  used  outdoors  could  result  in  the  development  of  large  communications  systems  that  could  adversely  impact  the  authorized  services.  For  that  reason,  we 
 are  prohibiting  the  use  of  antennas  attached  to  outside  structures  or  any  form  of  fixed  outdoor  infrastructure.  To  further  prevent  use  of  these  products  as  fixed  outdoor  systems,  we  are  requiring  that 
 these  devices  be  hand  held  products.  Further,  to  ensure  that  these  products  do  not  emit  energy  when  they  are  not  transmitting  information  to  an  associated  receiver,  we  are  requiring  that  hand  held  UWB  devices 
 be  designed  to  cease  transmission  within  ten  seconds  unless  an  acknowledgment  is  received  from  the  associated  receiver  that  the  transmission  is  being  received.  This  acknowledgment  of  reception  must 
 continue  to  be  received  by  the  UWB  transmitter  at  least  every  ten  seconds  in  order  for  the  UWB  transmitter  to  continue  transmission.  This  will  ensure  that  the  UWB  device  transmits  only  when  it  is 
 sending  information  to  an  associated  receiver.  Finally,  to  further  limit  the  proliferation  of  these  products 
 289  See  47  C.  F.  R.    2.106. 
 290  Prior  XSI  comments  indicated  that  UWB  operation  would  be  restricted  to  indoor  systems.  See,  for 
 example,  XSI  reply  comments  at  pg.  5  where  XSI  states  that  indoors  only  operation  should  be  required  until  the  Commission  has  developed  a  full  technical  record. 

 291  NTIA  acknowledged  building  attenuation  levels  of  9  dB  from  960-  3000  MHz,  12  dB  from  3000-  5650 
 MHz,  and  14  dB  from  5650-  7250  MHz.  See  NTIA  Special  Publication  01-  43,  supra,  at  pg.  5-  31. 
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 we  are  prohibiting  the  use  of  UWB  devices  for  the  operation  of  toys.  292  We  believe  that  these  conditions  reflect  our  desire  to  proceed  cautiously  with  the  introduction  of  UWB  equipment. 
 200.  Except  for  toys,  we  are  permitting  indoor  systems  to  be  used  for  any  type  of  application,  including  communication  systems,  provided  emissions  are  not  intentionally  directed  outside,  e.  g.,  through 
 a  window  or  doorway  to  perform  an  outside  function  such  as  the  detection  of  persons  about  to  enter  a  building.  We  also  are  prohibiting  the  use  of  fixed  outdoor  antennas,  such  as  antennas  mounted  on  the  side 
 or  top  of  a  building,  or  other  outdoors  infrastructure.  The  10  dB  UWB  bandwidth,  encompassing  both  the  center  frequency  of  operation  and  the  frequency  at  which  the  highest  radiated  emission  occurs,  must 
 be  greater  than  3.1  GHz.  This  will  remove  the  highest  emission  level  components  away  from  the  more  sensitive  radio  services  operating  below  this  frequency.  Building  shielding  combined  with  the  emission 
 limits  being  adopted  should  prevent  interference  to  the  authorized  services,  including  the  indoor  operation  of  cellular,  PCS  and  GPS  systems  employed  in  E-  911  applications.  293  However,  because  indoor  systems 
 will  be  permitted  to  operate  at  higher  emission  levels  than  outdoor  systems,  we  find  that  we  must  adopt  a  regulation  that  states  that  the  UWB  equipment,  by  the  nature  of  its  design,  must  be  capable  of  operation 
 only  indoors.  If  a  manufacturer  were  to  design  a  system  that  permits  peer-  to-  peer  operation  to  function  only  indoors,  we  will  permit  it.  An  example  would  be  where  peer-  to-  peer  operation  can  occur  only  when 
 an  emission  from  an  associated  base  station  also  is  detected.  A  necessity  to  operate  with  a  fixed  indoor  infrastructure  also  may  be  sufficient  to  demonstrate  indoors  only  operation.  This  action  is  consistent  with 
 the  method  we  used  with  unlicensed  PCS  to  ensure  that  portable  devices  were  not  introduced  into  areas  that  had  not  yet  been  cleared  of  existing  licensed  users.  294 

 201.  We  also  note  that  TDC  expressed  specific  interest  in  permitting  the  use  of  UWB  for  surveillance  systems.  295  These  are  radar  devices  that  establish  a  stationary  RF  perimeter  field,  similar  to 
 that  of  a  half-  bubble,  that  is  used  for  security  purposes  to  detect  the  intrusion  into  a  designated  area  by  persons  or  objects.  We  believe  that  TDCs  request  has  merit  but  remain  concerned  about  the  potential  for 
 the  proliferation  of  these  devices.  Accordingly,  we  are  requiring  the  same  coordination  procedures  that  we  applied  to  imaging  devices.  In  addition,  we  are  limiting  the  operation  of  surveillance  systems  to  law 
 enforcement,  fire  and  emergency  rescue  organizations,  to  public  utilities  and  to  industrial  entities.  These  parties  must  be  eligible  for  licensing  under  Part  90  of  our  rules. 

 5.  Emission  Levels  above  1990  MHz 
 202.  We  previously  discussed  the  analyses  of  potential  interference  to  U.  S.  Government  radio  operations,  amateur  operation  at  2450  MHz,  MMDS  operation  around  2500  MHz,  and  satellite  DARS  at 

 2320-  2345  MHz.  The  comments  also  addressed  concerns  regarding  possible  harmful  interference  to  several  other  radio  operations.  AT&  T  requests  that  additional  attenuation  be  provided  as  high  as  2600 
 MHz  to  protect  possible  future  3G  operations  and  also  requests  that  UNII  operation  at  5  GHz  be  protected.  296  Lucent  also  requests  additional  protection  for  future  3G  systems.  297  Motorola  lists  several 

 292  This  is  consistent  with  our  desire  to  proceed  cautiously  with  the  introduction  of  UWB  devices.  This  is  an 
 area  that  we  may  wish  to  readdress  in  our  further  review  of  the  UWB  standards  that  is  scheduled  to  occur  in  the  next  six  to  twelve  months. 

 293  Requiring  the  equipment  to  be  operated  indoors  also  should  provide  an  effect  similar  to  that  of  a  directional 
 antenna.  RF  emissions  would  not  be  directed  skyward  due  to  increased  rooftop  attenuation.  Variable  attenuation  of  the  building  walls  and  attenuation  by  randomly  placed  objects  within  the  building  will  reduce  the  probability  that 

 emissions  radiated  from  the  building  will  be  pointed  in  any  particular  direction.  294 
 47  C.  F.  R.    15.  307.  295 
 See,  for  example,  TDCs  ex  parte  filing  of  November  20,  2001.  296 
 AT&  T  comments  at  pg.  7-  8.  UNII  systems  operate  under  Part  15  and  are  not  entitled  to  protection  from  interference.  See  47  C.  F.  R.    15.5. 
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 operations  above  2  GHz  that  should  be  protected  from  UWB  operations,  such  as  3G,  MDS,  WCS,  and  others,  but  does  not  provide  any  information  to  demonstrate  that  UWB  devices  operating  on  these 
 frequencies  would  be  a  problem.  298 
 203.  We  note  that  the  10  dB  of  attenuation  below  the  Part  15  general  emission  limits  that  are  being  provided  in  the  frequency  range  of  1990-  3100  MHz  to  protect  various  U.  S.  Government  radio 

 operations  appears  to  be  more  than  sufficient  to  protect  non-  Government  operations  from  harmful  interference.  The  only  UWB  operations  not  subject  to  this  additional  10  dB  of  attenuation  are  through-  wall 
 imaging  systems  used  by  public  safety  organizations  and  surveillance  systems  employed  by  public  safety  organizations  and  by  public  utilities  and  industrial  entities.  As  used  in  this  Order,  the  reference  to  public 
 utilities  and  industrial  entities  refers  to  the  manufacturers  licensees,  petroleum  licensees  or  power  licensees  defined  in  47  C.  F.  R.    90.7.  We  believe  that  the  requirement  for  surveillance  systems  to  operate  at  the  Part 
 15  general  emission  limits  in  combination  with  the  coordination  procedures  are  sufficient  to  alleviate  concerns  of  harmful  interference. 

 204.  Except  for  imaging  devices  operating  below  960  MHz,  through-  wall  systems,  surveillance  systems  and  vehicular  radars,  all  other  UWB  devices  are  being  required  to  operate  with  their 
 10  dB  bandwidth  between  3.1-  10.6  GHz.  Above  3.  1  GHz,  it  appears  that  the  Part  15  general  emission  limits  are  sufficient  to  protect  the  various  authorized  radio  services  from  harmful  interference.  The  upper 
 frequency  limit  of  10,600  MHz  provides  additional  protection  to  the  passive  satellite  receiving  system  frequency  band  at  10,600-  10,700  MHz.  Only  vehicle  radar  systems  are  being  permitted  to  operate  with 
 their  -10  dB  bandwidth  between  22-  29  GHz.  Further,  as  requested  by  NTIA  we  are  requiring  that  unwanted  emissions  from  vehicle  radar  systems  be  attenuated  20  dB  below  the  Part  15  general  limits  if  they 
 are  outside  the  22-  31  GHz  band  and  10  dB  below  the  Part  15  general  limits  if  they  are  in  the  band  29-  31  GHz.  The  filing  from  SARA  indicated  that  their  equipment  could  comply  with  such  an  emission  limit.  299 

 6.  Dithering  and  Other  Noise-  Like  Emission  Requirements 
 205.  As  discussed  earlier,  the  measured  level  at  which  interference  occurred  to  a  GPS  C/  A  code  receiver  was  8  dB  lower  for  a  CW-  like  UWB  emission  than  that  at  which  interference  occurred  from 

 a  noise-  like  UWB  emission.  This  8  dB  difference  is  in  agreement  with  the  international  standards,  which  specify  that  CW-  like  emissions  necessitate  10  dB  of  additional  interference  protection.  300  Because  a  CW-like 
 emission  consists  of  narrow  spectral  lines,  the  standard  is  specified  as  the  signal  level  contained  within  a  700  Hz  bandwidth. 

 206.  We  concur  with  the  test  data  and  international  standards  that  an  additional  10  dB  of  protection  should  be  provided  to  GPS  emissions  from  CW-  like,  narrowband  emissions  produced  by  the 
 UWB  transmitter.  However,  we  note  that  a  700  Hz  bandwidth  setting  is  not  available  on  the  measurement  instrumentation,  such  as  a  spectrum  analyzer.  XSI  agreed  with  USGPSIC  that  this  10  dB  of 
 suppression  could  be  demonstrated  using  a  10  kHz  resolution  bandwidth.  301  We  also  agree  that  a  10  kHz  resolution  bandwidth  could  be  used  to  demonstrate  that  the  CW-  like  emissions  are  suppressed  10  dB 

 (...  continued  from  previous  page)  297  Lucent  comments  at  pg.  7. 
 298  Motorola  comments  at  pg.  36.  While  Motorola  in  its  comments  requested  that  UWB  systems  be  required  to 
 attenuate  emissions  12  dB  below  the  Part  15  general  limits,  it  later  requested  that  18  dB  of  attenuation  be  required  but  supplied  no  data  to  support  its  request.  Motorola  reply  comments  at  pg.  2  and  7. 

 299  See,  for  example,  the  ex  parte  comments  of  December  5,  2001,  from  DaimlerChrysler  and  SARA  on  pg. 
 14.  300 
 Recommendation  ITU-  R  M.  1477,  supra.  301 
 XSI  comment  of  7/  25/  01responding  to  the  USGPSIC  comment  of  6/  21/  01. 
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 below  the  limits  applicable  to  noise-  like  emissions.  302  However,  we  wish  to  specify  the  measurement  bandwidth  as  close  as  possible  to  the  specification  employed  in  the  ITU-  R  recommendation.  While  a  700 
 Hz  resolution  bandwidth  is  not  available,  the  use  of  a  1  kHz  resolution  bandwidth  is  adequate  for  this  measurement.  A  CW-  like  emission  will  have  the  same  emission  level  whether  it  is  measured  with  a  1 
 kHz,  a  10  kHz  or  a  1  MHz  resolution  bandwidth.  Thus,  we  are  requiring  the  average  emissions  appearing  within  the  GPS  frequency  bands,  1164-  1240  MHz  and  1559-  1610  MHz,  when  measured  with  a  resolution 
 bandwidth  of  no  less  than  1  kHz,  to  be  attenuated  by  10  dB  below  the  average  limit  specified  for  a  1  MHz  resolution  bandwidth,  i.  e.,  the  noise-  like  emission  limit.  Specifying  the  resolution  bandwidth  for  the  CW-like 
 measurement  as  no  less  than  1  kHz  permits  noise-  like  UWB  systems  to  be  tested  with  a  wider  bandwidth  so  that  testing  time  may  be  reduced.  303 

 7.  Emissions  from  Incorporated  Digital  Devices 
 207.  We  note  that  many  UWB  transmission  systems  will  incorporate  digital  devices  that,  by  themselves,  will  radiate  RF  emissions.  We  also  note  that  requiring  the  emissions  from  these  digital 

 devices  to  comply  with  some  of  the  reduced  levels  being  adopted  in  this  proceeding  may  make  production  infeasible.  We  see  no  reason,  based  on  the  submissions  in  this  proceeding,  that  emissions  from  associated 
 digital  circuitry  should  be  required  to  have  any  greater  attenuation  than  required  under  the  current  rules.  To  do  so  may  make  it  technically  infeasible  or  overly  expensive  to  design  UWB  devices.  However,  we 
 note  that  the  digital  circuitry  used  with  a  transmitter  for  the  purpose  of  enabling  the  operation  of  the  transmitter  is  not  defined  as  a  digital  device  but  is  considered  to  be  part  of  the  transmitter.  Thus,  this 
 digital  circuitry  would  normally  be  subject  to  the  emission  limits  applicable  to  the  transmitter.  Under  the  current  rules,  emissions  from  digital  circuitry  used  to  enable  the  operation  of  the  transmitter  are  not 
 required  to  be  reduced  below  the  general  limits  in  47  C.  F.  R.    15.209.  We  see  no  reason  to  change  this  existing  provision.  Accordingly,  we  are  permitting  the  emissions  from  digital  circuitry  used  to  enable  the 
 operation  of  an  UWB  device  to  operate  at  the  limits  contained  in  47  CFR    15.209  provided  it  can  be  clearly  demonstrated  that  those  emissions  are  due  solely  to  emissions  from  the  digital  circuitry  and  are  not 
 intended  to  be  radiated  from  the  antenna.  We  are  not  addressing  distinctions  between  Class  A  and  B  digital  devices  as  this  is  not  considered  in  the  current  regulations.  However,  if  the  digital  circuitry  is  used 
 to  control  additional  functions  or  capabilities,  i.  e.,  it  complies  with  the  definition  in  47  C.  F.  R.    15.3(  k)  for  a  digital  device,  that  aspect  of  the  digital  circuitry  may  comply  with  the  standards  for  a  Class  A  digital 
 device  or  a  Class  B  digital  device,  as  applicable,  in  accordance  with  the  current  rules. 
 8.  Peak  Emission  Limits 
 208.  Proposal.  In  the  Notice,  the  Commission  noted  that  the  peak  output  level  does  not  directly  impact  the  interference  seen  by  a  narrowband  receiver.  It  is  the  power  spectral  density  of  the 

 pulse  and  the  pulse  repetition  frequency  that  are  important  for  controlling  potential  interference.  However,  a  limit  on  peak  emissions  is  necessary  to  reduce  the  potential  for  UWB  emitters  to  cause 
 harmful  interference  to  radio  operations  above  1  GHz.  The  Commission  proposed  two  methods  of  measuring  peak  emission  levels:  1)  the  peak  level  of  the  emission  when  measured  over  a  bandwidth  of  50 
 MHz  which  is  comparable  to  the  widest  victim  receiver  that  is  likely  to  be  encountered,  and  2)  the 
 302  If  the  signal  is  noise-  like,  the  reduction  from  a  1  MHz  resolution  to  a  10  kHz  resolution  bandwidth  would 
 cause  a  20  dB  reduction  in  the  measured  signal  level.  303 
 A  true  CW-  like  emission  will  have  the  same  measured  emission  level  regardless  of  the  resolution  bandwidth  provided  only  one  spectral  line  is  contained  within  the  bandwidth  of  the  measuring  instrument.  A  true 

 noise-  like  emission  will  change  by  10  dB  for  every  10  percent  change  in  the  measurement  bandwidth,  i.  e.,  a  signal  measured  to  be  30  dBm  with  a  1  MHz  resolution  bandwidth  will  be  60  dBm  when  measured  with  a  1  kHz 
 resolution  bandwidth.  When  noise-  like  and  CW-  like  emissions  are  mixed,  as  with  most  UWB  operations,  the  measured  UWB  emission  will  decrease  logarithmically  with  the  decrease  in  resolution  bandwidth  until  the  imbedded 
 CW  emissions  begin  to  be  detected  and  resolved. 
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 absolute  peak  output  of  the  emission  over  its  entire  bandwidth.  Comments  were  requested  on  the  suitability  of  these  two  measurements  with  regard  to  the  potential  for  interference  from  UWB  transmitters 
 to  wideband  receivers  used  in  the  licensed  radio  services. 
 209.  In  the  case  of  the  first  definition  of  peak  level,  i.  e.,  the  peak  signal  strength  measured  over  a  50  MHz  bandwidth,  the  Commission  proposed  to  apply  a  20  dB  limit  with  respect  to  the  maximum 

 permitted  average  emission  level.  304  This  limit  is  consistent  with  the  limit  currently  contained  in  47  C.  F.  R.    15.35(  b).  It  also  proposed  that  the  absolute  peak  limit  for  the  emission  over  its  entire  bandwidth 
 be  variable  based  on  the  amount  the  10  dB  bandwidth  of  the  UWB  emission  exceeds  50  MHz.  The  Commission  proposed  to  use  the  following  formula  to  calculate  the  amount  that  the  absolute  peak 
 emission  level  over  the  entire  bandwidth  of  the  UWB  emission  would  be  permitted  to  exceed  the  Part  15  average  emission  limit:  [20  +  20log10(-  10  dB  bandwidth  of  the  UWB  emission  in  Hertz/  50  MHz)]  dB 
 with  the  further  stipulation  that  the  absolute  peak  emission  level  not  be  permitted  to  exceed  the  average  limit  by  more  than  60  dB.  305  This  60  dB  limit  is  comparable  with  the  limit  permitted  under  the  waivers 
 recently  issued  to  Time  Domain  Corporation,  U.  S.  Radar  Inc.  and  Zircon  Corporation.  306  Comments  were  requested  on  whether  wideband  receivers  used  in  the  licensed  services  are  sensitive  to  peak  signal  level  in 
 a  unit  bandwidth,  such  as  the  50  MHz  referenced  above,  or  to  the  total  peak  emission  produced  by  the  USB  device,  and  whether  both  peak  limits  are  needed  to  reduce  potential  interference  to  the  authorized 
 radio  services.  If  only  one  peak  limit  is  needed,  the  comments  should  indicate  which  limit  is  appropriate.  The  Commission  indicated  that  it  intended  to  rely  heavily  on  submitted  test  data  in  determining  what  peak 
 emission  standards  should  apply  to  UWB  products. 
 210.  The  Commission  requested  comments  as  to  whether  the  higher  absolute  peak  limit  will  cause  increased  interference  problems,  especially  using  the  proposed  measurement  procedures  and  the 

 limitations  on  frequency  bands  of  operation.  Comments  were  requested  on  the  proposed  method  of  varying  the  absolute  peak  emission  limit  and  whether  other  features,  such  as  the  excess  bandwidth,  i.  e., 
 the  amount  of  the  occupied  bandwidth/  effective  data  rate  exceeds  a  specified  level  such  as  10  dB,  should  be  employed  in  calculating  a  peak  limit. 

 211.  Comments.  Several  of  the  comments  agreed  with  our  specifying  a  peak  limit  over  a  50  MHz  bandwidth.  As  stated  by  AOPA,  50  MHz  is  ample  for  current  GPS,  GLONASS  and  AMS(  R)  S 
 receivers  which  have  a  front  end  bandwidth  of  about  30  MHz.  307  NBAA  agreed  that  a  50  MHz  bandwidth  is  appropriate  for  protection  of  the  current  radio  services.  308  AOPA  and  NBAA  noted  the  possibility  that 
 wider  bandwidths  may  be  needed  in  the  future  if  UWB  is  found  to  have  operational  and  spectrum  efficiency  advantages  that  make  it  desirable  for  use  in  aeronautical  communications.  Similarly,  Valeo 
 Electronics  stated  that  the  proposal  to  measure  peak  over  50  MHz  is  appropriate  and  comparable  to  the  worst  case  of  a  likely  victim  receiver.  309  It  also  noted  that  adoption  of  this  standard  would  make  it 

 304  The  average  limit  above  1000  MHz,  500  uV/  m,  as  measured  at  3  meters,  is  equivalent  to  an  equivalent 
 isotropically  radiated  power  (EIRP)  of  41.  25  dBm/  MHz.  Thus,  the  proposed  peak  limit  in  a  50  MHz  band  would  be  5000  uV/  m,  as  measured  at  3  meters,  or  21.25  dBm/  50  MHz  EIRP.  It  appears  that  several  of  the  commenters 

 mistakenly  believed  that  the  Commission  proposed  to  apply  a  limit  to  the  peak-  to-  average  ratio  of  the  UWB  transmission  instead  of  to  the  peak  emission  level. 
 305  This  would  be  equivalent  to  a  total  peak  EIRP  of  +18.75  dBm. 
 306  See  waivers  issued  on  June  29,  1999,  by  the  Chief,  Office  of  Engineering  and  Technology.  While  the 
 waivers  stated  that  the  maximum  peak-  to-  average  ratio  was  limited  to  30  dB,  these  ratios  were  calculated  using  10  log10[(  pulse  width)  x  (pulse  repetition  frequency)]  dB.  For  conventional  pulses,  the  calculation  would  have  been 

 based  on  a  20  log10  factor,  resulting  in  a  maximum  60  dB  peak-  to-  average  ratio.  307 
 AOPA  comments  at  pg.  14.  308 
 NBAA  comments  at  pg.  15.  309 
 Valeo  Electronics  comments  at  pg.  11. 
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 unnecessary  to  specify  a  limit  on  the  total  peak  signal  level.  TDC  also  objected  to  a  limit  on  total  peak  signal  level  as  it  would  be  relevant  only  to  receivers  that  have  a  bandwidth  wide  enough  to  receive  the 
 entire  UWB  transmission.  310  Nortel  noted  that  future  software-  defined  receivers  will  use  wider  bandwidths  and  that  a  50  MHz  bandwidth  would  not  seem  unreasonable  in  a  few  years.  311  Bosch  also 
 agreed  that  a  50  MHz  bandwidth  was  a  practical  standard  for  a  wideband  receiver.  312 
 212.  ANRO  requested  a  limit  on  the  total  peak  level,  noting  that  peak  measurements  over  a  50  MHz  BW  would  be  difficult  and  citing  an  uncertainty  as  to  where  in  the  spectrum  50  MHz  measurements 

 should  be  made.  313  On  the  other  hand,  Kohler  noted  that  the  proposal  to  establish  an  absolute  peak  limit  based  on  the  bandwidth  of  the  UWB  transmission  would  encourage  manufacturers  to  employ  as  wide  a 
 bandwidth  as  possible  in  order  to  increase  the  peak  limit  and  result  in  greater  UWB  intrusion  into  a  broader  range  of  frequencies.  314  SiRF  Technology,  Inc.  &  Trimble  Navigation  request  that  peak  power  be 
 measured  on  a  per-  nanosecond  basis.  315  USGPSIC  also  requested  that  peak  power  be  measured  on  a  per  nanosecond  basis  believing  that  otherwise  UWB  devices  would  be  permitted  to  emit  peak  power 
 levels  in  excess  of  a  megawatt.  316  XSI  noted  that  the  calculation  by  USGPSIC  requires  the  use  of  an  impractical  PRF  of  1  second  and  that  the  average  level  employed  by  USGPSIC  is  50  dB  higher  than  that 
 proposed  in  the  Notice  for  emissions  in  the  GPS  band.  317 
 213.  The  commenters  did  not  agree  on  the  peak  signal  limit  that  should  be  employed.  TDC,  noting  that  the  absence  of  peak  limits  would  allow  UWB  systems  operating  at  low  PRFs  to  emit 

 enormous  pulse  levels,  stated  that  it  was  not  clear  how  a  50  MHz  measurement  bandwidth  and  a  limit  of  20  dB  above  the  average  limit  were  indicative  of  interference  potential  and  that  there  was  no  justification 
 provided  for  these  values.  318  TDC  later  requested  that  the  peak  power  in  a  50  MHz  band  be  limited  to  0  dBm  EIRP.  319  Kohler  notes  that  its  system  operates  at  an  average  level  of  47.3  dBm/  MHz  and  a  total 
 peak  signal  of  +7  dBm.  320  XSI  stated  that  its  equipment  operates  with  a  5  dB  peak  to  average  ratio.  321  CSSIP  requested  that  a  peak  limit  apply  below  1000  MHz.  322  This  limit,  as  measured  in  a  6  MHz 
 bandwidth,  would  be  20  dB  greater  than  the  quasi-  peak  limit. 
 214.  Discussion.  There  are  two  reasons  for  imposing  a  peak  emission  limit  on  UWB  devices. 

 310  TDC  comments  at  pg.  34. 
 311  Nortel  comments  at  pg.  4. 
 312  Bosch  comments  at  pg.  5. 
 313  ANRO  comments  at  pg.  2.  ANRO  also  requested  peak  limits  of  2  kW  for  UWB  systems  using  directional 
 antennas.  314 
 Kohler  comments  at  pg.  5-  6.  315 
 SiRF  Technology,  Inc.  &  Trimble  Navigation  joint  reply  comments  at  pg.  3.  316 
 USGPSIC  comments  at  pg.  41-  42.  The  USGPSIC  stated  that  this  high  power  would  occur  from  the  use  of  a  1  mW  average  UWB  transmission  using  a  pulse  width  of  1  nS. 

 317  XSI  reply  comments  at  pg.  6. 
 318  TDC  comments  at  pg.  32-  33. 
 319  TDC  comments  of  3/  12/  01  at  pg.  17. 
 320  Kohler  reply  comments  at  pg.  2. 
 321  XSI  reply  comments  at  pg.  5.  It  appears  that  the  5  dB  peak  to  average  applies  to  average  and  peak 
 measurements  over  the  same  1  MHz  bandwidth.  322 
 CSSIP  comments  at  pg.  2.  We  note  that  the  quasi-  peak  measurement  closely  approximates  the  peak  level  of  a  pulsed  emission.  Accordingly,  we  see  no  reason  to  apply  a  peak  limit  on  top  of  a  quasi-  peak  limit. 
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 The  first,  and  most  obvious,  is  to  keep  from  overloading  the  front  end  of  a  nearby  victim  receiver.  For  example,  the  interference  protection  level  for  C/  A-  code  GPS  receivers  from  low  duty  cycle  pulse-  like 
 emissions  is  +20  dBm  peak  pulse  power  at  the  receiver  input.  323  This  is  considerably  higher  than  the  signal  levels  we  are  considering  in  this  proceeding.  The  second  reason  is  because  pulsed  emissions  with 
 low  PRFs  have  high  peak-  to-  average  ratios  and  victim  receivers  will  respond  to  the  peak  signal  level  produced  by  the  UWB  transmitter  if  their  bandwidth  is  wider  than  the  UWB  PRF.  Thus,  we  need  to 
 address  the  potential  total  peak  power  that  will  be  received  in  the  bandwidth  employed  by  the  victim  receiver.  The  total  peak  power  produced  by  the  UWB  device  is  not  relevant  to  interference  potential  as 
 there  are  no  receivers  employed  with  the  authorized  radio  services  that  operate  at  the  bandwidths  employed  by  UWB  emissions.  For  that  reason,  we  are  not  adopting  a  limit  on  total  peak  power.  The 
 comments  generally  agreed  that  50  MHz  is  about  the  widest  bandwidth  that  would  be  employed  by  victim  radio  receivers.  Thus,  there  appears  to  be  no  reason  to  measure  peak  power  across  a  wider  bandwidth. 

 215.  The  low  proliferation,  infrequent  operation,  operation  near  the  ground,  rapid  attenuation  of  emitted  signals,  and  general  operation  in  the  presence  of  surrounding  objects  that  would  further 
 attenuate  the  emissions  should  result  in  a  low  interference  potential  from  GPRs  and  other  imaging  systems.  324  Vehicular  radar  systems  operate  above  24  GHz  where  the  emissions  will  attenuate  rapidly 
 with  distance  and  there  is  a  high  probability  of  intervening  objects  further  attenuating  the  UWB  emissions  and  reducing  the  probability  of  harmful  interference.  We  expect  that  most  indoor  and  hand  held  systems 
 would  operate  at  high  PRF  levels,  resulting  in  potential  victim  receivers  reacting  only  to  the  average  emission  levels  produced  by  the  UWB  devices.  However,  some  UWB  devices  may  be  designed  to 
 operate  at  a  low  PRF  with  a  resulting  high  peak-  to-  average  ratio.  This  could  result  in  the  peak  power  level  being  a  controlling  factor  in  potential  interference  to  other  receivers.  Accordingly,  we  believe  that  a 
 peak  limit  is  needed  to  ensure  that  nearby  victim  receivers  are  not  affected. 
 216.  In  the  Notice,  the  Commission  proposed  a  peak  power  limit  in  a  50  MHz  band  equal  to  20  dB  greater  than  the  maximum  permitted  average  limit.  The  average  limit  is  500  uV/  m,  as  measured  at  3 

 meters  with  a  1  MHz  resolution  bandwidth.  This  is  equivalent  to  an  EIRP  of  41.25  dBm/  MHz.  325  Thus,  the  peak  power  limit  proposed  in  the  Notice  was  equivalent  to  an  EIRP  of  21.25  dBm/  50  MHz.  The 
 comments  generally  did  not  address  interference  at  the  peak  limits  being  considered.  Because  of  this,  we  performed  our  own  analysis  on  the  effect  of  peak  power  to  a  generic  communications  receiver.  326  We 
 found  that  a  suitable  peak  EIRP  power  limit  for  a  transmitter  placed  3  meters  away  would  be  33.7  dBm/  MHz.  For  a  transmitter  placed  10  meters  away,  the  peak  EIRP  limit  would  be  23.3  dBm/  MHz. 
 We  also  note  that  the  peak  limit  needs  to  be  applied  at  only  one  location,  i.  e.,  centered  on  the  frequency  at  which  the  highest  level  emission  occurs.  327 

 217.  As  noted  in  the  section  on  Measurement  Procedures,  we  find  that  peak  measurements  based  on  a  50  MHz  (resolution)  bandwidth  may  not  be  feasible.  The  widest  readily  available  resolution 
 bandwidth  that  can  be  employed  for  peak  measurements  is  3  MHz.  Consequently,  we  prepared  a  comparison  of  the  differences  in  peak-  to-  average  ratios,  based  on  an  average  signal  measured  with  a  1 
 MHz  resolution  bandwidth  (RBW),  as  the  PRF  of  the  UWB  emission  and  the  RBW  of  the  measuring 

 323  NTIA  Special  Publication  01-  45,  supra,  at  pg.  4-  3. 
 324  We  also  note  that  many  GPRs  and  imaging  systems  will  operate  below  1000  MHz  where  they  are  subject  to 
 a  quasi-  peak  emission  limit.  The  quasi-  peak  emission  limit  should  closely  approximate  the  peak  levels  produced  by  these  devices. 

 325  There  is  a  direct  correlation  between  EIRP  and  field  strength.  Field  strength  in  dBuV/  m  at  3  meters  equals 
 EIRP  (in  dBm)  plus  95.  2.  326 
 Our  initial  analysis  of  the  effect  on  a  QPSK  system  has  been  placed  in  the  docket  file  for  this  proceeding.  327 
 The  bandwidth  of  the  measuring  instrument  would  be  centered  on  this  frequency. 
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 instrument  are  varied.  328  These  graphs,  shown  in  Appendix  E  to  this  Report  and  Order,  compare  emissions  from  conventional  pulsed  transmissions  and  dithered  (Gaussian)  pulsed  transmissions. 
 218.  As  shown  in  the  graph,  the  peak  EIRP  signal  level  of  21.25  dBm/  50  MHz  329  that  was  proposed  in  the  Notice  results  in  non-  dithered  pulsed  emissions  being  average-  limited  if  the  PRF  is 
 greater  than  11.  11  MHz  and  all  dithered  UWB  emissions  being  peak-  limited.  330  If  the  RBW  is  reduced  to  3  MHz,  the  relationship  is  based  on  a  20  log  factor  resulting  in  a  decrease  in  the  peak  level  allowed  with  a 
 50  MHz  RBW  by  24.  44  dB.  This  results  in  an  allowable  peak  level  of  45.69Bm/  3  MHz,  a  level  that  is  4.44  dB  lower  than  the  permissible  average  limit  with  a  1  MHz  RBW.  Reducing  this  further  to 
 measurement  with  a  1  MHz  RBW  lowers  the  permissible  peak  level  to  55.23  dBm/  MHz,  14  dB  below  the  average  limit.  In  actual  practice,  we  would  not  specify  a  peak  level  lower  than  the  average  limit.  It 
 should  be  noted  that  a  conventional  pulsed  modulated  emission  would  not  have  a  peak  emission  higher  than  the  average  limit  at  PRFs  greater  than  the  RBW  employed  divided  by  0.45. 

 219.  Based  on  the  above,  we  believe  that  our  proposal  to  permit  a  peak  emission  within  a  50  MHz  RBW  of  only  21.25  dBm  EIRP  is  too  conservative.  We  believe  that  the  peak  emission  level  of  0 
 dBm/  50  MHz,  equivalent  to  58  mV/  m  at  3  meters,  requested  by  TDC  would  not  result  in  harmful  interference  problems  to  communications  systems.  This  level  translates  to  a  peak  EIRP  of  24.44  dBm/  3 
 MHz  or  3.6  uW/  3  MHz,  or  to  a  peak  field  strength  of  3.46  mV/  m  at  measured  at  3  meters  with  a  3  MHz  RBW.  This  peak  level  is  16.  8  dB  higher  than  the  average  level  determined  with  a  1  MHz  RBW  and  is  3.2 
 dB  lower  than  the  peak  limit  permitted  under  the  current  Part  15  rules.  331  It  results  in  dithered  and  non-dithered  UWB  emissions  being  average-  limited  for  PRFs  greater  than  1  MHz  and  peak-  limited  for  PRFs 
 below  1  MHz. 
 220.  Our  conversion  from  a  50  MHz  resolution  bandwidth  to  a  3  MHz  resolution  bandwidth  is  based  on  the  worse  case  assumption  that  changes  in  the  peak  levels  changes  follow  the  square  of  the 

 change  in  the  resolution  bandwidth.  That  is,  the  change  in  the  allowable  peak  limit  at  50  MHz  to  a  peak  limit  at  3  MHz  was  based  on  20  log  (3/  50)  dB.  We  recognize  that  this  could  penalize  some  UWB 
 operations,  particularly  those  operating  with  PRFs  greater  than  around  6.7  MHz.  According,  we  are  adopting  a  peak  limit  based  on  a  sliding  scale  dependent  on  the  actual  resolution  bandwidth  employed  in 
 the  measurement.  The  peak  EIRP  limit  being  adopted  in  this  Report  and  Order  is  0  dBm  when  measured  with  a  resolution  bandwidth  of  50  MHz  and  20  log  (RBW/  50)  dBm  when  measured  with  a  resolution 
 bandwidth  ranging  from  1  MHz  to  50  MHz.  RBW  is  the  resolution  bandwidth,  in  megahertz,  actually  employed.  The  minimum  resolution  bandwidth  that  may  be  employed  is  1  MHz;  the  maximum  resolution 
 bandwidth  that  may  be  employed  is  50  MHz. 

 328  The  formulas  needed  to  perform  this  analysis  are  contained  in  NTIA  Special  Publication  01-  43,  supra,  at 
 pg.  D-  1  through  D-  2.  329 
 This  equates  to  a  20  dB  peak-  to-  average  level  for  the  50  MHz  RBW  curve.  330 
 Average-  limited  means  that  the  average  emission  level  will  be  the  determining  standard  on  whether  the  equipment  complies  with  the  standards.  If  the  emissions  from  the  device  meet  the  average  limit,  they  will  also  meet 

 the  peak  limit.  Peak-  limited  is  the  counter  to  this  where  if  the  device  meets  the  peak  limit,  it  will  also  comply  with  the  average  limit.  However,  it  must  be  noted  that  the  graphs  are  based  on  ideal  pulse  characteristics.  Because 
 of  extraneous  emissions,  e.  g.,  emissions  from  an  associated  digital  device,  antenna  effects,  different  pulse  shapes,  and  other  factors  it  remains  necessary  to  specify  both  peak  and  average  emissions. 
 331  The  peak  limit  above  1000  MHz  is  5  mV/  m.  This  is  equivalent  to  21.  25  dBm  EIRP.  See  47  C.  F.  R.   
 15.  33(  b)  and  15.  209.  However,  it  must  be  remembered  that  the  peak  limit  in  the  current  Part  15  rules  is  based  on  the  total  peak  emission  level  and  not  on  a  peak  level  over  a  specified  bandwidth. 
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 9.  AC  Power  Line  Conducted  Limits 
 221.  In  the  Notice,  the  Commission  proposed  to  retain  the  existing  limit  in  47  CFR  Section  15.207  for  controlling  the  amount  of  energy  permitted  to  be  conducted  onto  the  AC  power  lines  as  a 

 reasonable  starting  point  for  establishing  standards  until  additional  experience  can  be  gained  with  this  equipment.  332  None  of  the  comments  objected  to  retaining  the  existing  Part  15  limits  on  RF  energy 
 conducted  onto  the  AC  power  lines.  333  We  concur  and  are  adopting  a  limit  of  250  uV  over  the  frequency  range  of  450  kHz  to  30  MHz,  as  proposed  in  the  Notice. 

 10.  Summary  of  Emission  Limits  Being  Adopted  in  this  Report  and  Order 
 222.  As  stated  in  the  Notice,  the  establishment  of  emission  limits  requires  a  firm  understanding  of  the  characteristics  of  UWB  signals,  their  impact  on  victim  receivers,  and  the  minimum  separation 

 distance  between  UWB  devices  and  victim  receivers;  almost  any  transmitter  will  cause  interference  if  it  is  too  close  to  a  receiver.  334  We  have  attempted  to  apply  the  data  submitted  in  the  various  comments,  tests 
 and  analyses  to  determine  what  emission  limits  are  acceptable  for  UWB  operation.  Our  task  was  to  determine  limits  based  on  reasonable,  real-  world  applications  and  not  just  on  the  results  of  laboratory 
 measurements  conducted  in  anechoic  chambers.  While  such  measurements  are  necessary  to  determine  if  further  investigations  are  necessary  or  additional  caution  should  be  applied,  they  demonstrate  the  possible 
 performance  capabilities  of  products  in  the  absence  of  other  RF  noise  sources.  In  some  cases,  we  have  adjusted  the  levels  determined  from  the  various  analyses  to  reflect  our  desire  and  the  desire  of  NTIA  to 
 proceed  cautiously.  335 
 223.  The  limits  we  are  adopting  in  this  proceeding  are  considerably  lower  in  some  frequency  ranges  than  the  current  Part  15  levels.  While  these  limits  may  prove  to  be  lower  than  what  is  necessary, 

 we  believe  that  such  caution  is  needed  in  the  early  stages  of  UWB  implementation.  Once  additional  experience  is  gained  with  this  equipment  and  a  better  understanding  develops  regarding  operating 
 frequency  and  allowable  emissions  levels,  we  may  be  able  to  revisit  these  limits.  In  the  interim,  the  following  summarizes  the  emission  limits  being  adopted  in  this  Report  and  Order. 

 224.  Based  on  the  proceeding  discussion,  we  are  adopting  the  following  emission  limits  for  UWB  devices: 
 -  Coordinated  GPRs,  wall  imaging  and  through-  wall  imaging  systems  may  operate  with  the  10  dB  bandwidth  below  960  MHz  at  the  Part  15  general  emission  limits  provided  emissions  in  the 
 960-  1610  MHz  band  are  attenuated  below  the  general  limits  by  24  dB;  narrowband  emissions  in  the  GPS  bands  are  attenuated  below  the  general  limits  by  34  dB;  emissions  in  the  1610-  1990 
 MHz  are  attenuated  below  the  general  limits  by  12  dB;  and  emissions  above  1990  MHz  are  attenuated  below  the  general  limits  by  10  dB.  There  are  usage  restrictions  and  a  labelling 
 requirement. 
 -  Coordinated  through-  wall  imaging  systems  and  surveillance  systems  may  operate  with  the   

 332  The  Commission  proposed  to  modify  the  AC  power  line  conducted  emission  limits  in  47  C.  F.  R.    15.207. 
 See  Notice  of  Proposed  Rule  Making  in  ET  Docket  No.  98-  80,  64  Fed.  Reg.  62159,  November  16,  1999,  http://  www.  fcc.  gov/  Bureaus/  Engineering_  Technology/  Notices/  1999/  fcc99296.  wp. 

 333  See,  for  example,  the  comments  of  ARRL  at  pg.  16,  A.  Peter  Annan  at  pg.  7,  and  TDC  at  pg.  34.  While 
 Mr.  Annans  comments  address  conducted  limits  applicable  to  digital  devices,  UWB  devices  are  intentional  radiators  though  they  also  may  contain  digital  circuitry. 

 334  Notice,  supra,  at  para.  32. 
 335  See  letter  of  February  13,  2002,  from  William  Hatch,  supra. 
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 10  dB  bandwidth  within  the  band  1990  MHz  to  10,600  MHz  at  the  Part  15  general  emission  limits  provided  emissions  below  960  MHz  do  not  exceed  the  general  limits;  emissions  in  the 
 960-  1610  MHz  band  are  attenuated  below  the  general  limits  by  12  dB;  narrowband  emissions  in  the  GPS  bands  are  attenuated  below  the  general  limits  by  22  dB;  emissions  in  the  1610- 
 1990  MHz  band  are  attenuated  below  the  general  limits  by  10  dB;  and  emissions  above  10,600  MHz  are  attenuated  below  the  general  limits  by  10  dB.  There  are  usage  restrictions  and 
 a  labelling  requirement. 
 -  Coordinated  GPRs,  wall  imaging  and  medical  imaging  systems  may  operate  with  the  10  dB  bandwidth  within  the  band  3100  MHz  to  10,600  MHz  at  the  Part  15  general  emission  limits 

 provided  emissions  below  960  MHz  do  not  exceed  the  general  limits;  emissions  in  the  960-  1610  MHz  band  are  attenuated  below  the  general  limits  by  24  dB;  narrowband  emissions  in 
 the  GPS  bands  are  attenuated  below  the  general  limits  by  34  dB;  emissions  in  the  1610-  1990  MHz  band  are  attenuated  below  the  general  limits  by  12  dB;  emissions  in  the  1990-  3100 
 MHz  band  are  attenuated  below  the  general  limits  by  10  dB;  and  emissions  above  10,600  MHz  are  attenuated  below  the  general  limits  by  10  dB.  There  are  usage  restrictions  and  a 
 labelling  requirement. 
 -  Indoor-  only  systems  may  operate  with  the  10  dB  bandwidth  within  the  band  3100  MHz  to  10,600  MHz  provided  emissions  below  960  MHz  do  not  exceed  the  general  limits;  emissions 
 in  the  960-  1610  MHz  band  are  attenuated  below  the  general  limits  by  34  dB;  narrowband  emissions  in  the  GPS  bands  are  attenuated  below  the  general  limits  by  44  dB;  emissions  in 
 the  1610-  1990  MHz  band  are  attenuated  below  the  general  limits  by  12  dB;  emissions  in  the  1990-  3100  MHz  band  are  attenuated  below  the  general  limits  by  10  dB;  and  emissions  above 
 10,600  MHz  are  attenuated  below  the  general  limits  by  10  dB.  There  is  a  labelling  requirement. 

 -  Hand  held  systems  may  operate  with  the  10  bandwidth  within  the  band  3100  MHz  to  10,600  MHz  provided  emissions  below  960  MHz  do  not  exceed  the  general  limits;  emissions  in  the 
 960-  1610  MHz  band  are  attenuated  below  the  general  limits  by  34  dB;  narrowband  emissions  in  the  GPS  bands  are  attenuated  below  the  general  limits  by  44  dB;  emissions  in  the  1610- 
 1990  MHz  band  are  attenuated  below  the  general  limits  by  22  dB;  emissions  in  the  1990-  3100  MHz  band  are  attenuated  below  the  general  limits  by  20  dB;  and  emissions  above 
 10,600  MHz  are  attenuated  below  the  general  limits  by  20  dB. 
 -  Vehicular  radar  systems  may  operate  with  the  -10  dB  bandwidth  within  the  22-  29  GHz  and  with  the  center  frequency  and  the  frequency  at  which  the  maximum  emission  occurs  both 
 located  above  24.075  GHz  provided  emissions  below  960  MHz  do  not  exceed  the  general  limits;  emissions  in  the  960-  1610  MHz  band  are  attenuated  below  the  general  limits  by  34 
 dB;  narrowband  emissions  in  the  GPS  bands  are  attenuated  below  the  general  limits  by  44  dB;  emissions  in  the  1610-  22,000  MHz  band  and  in  the  band  above  31  GHz  are  attenuated 
 below  the  general  limits  by  20  dB;  and  emissions  between  29  GHz  and  31  GHz  are  attenuated  below  the  general  limits  by  10  dB. 

 225.  For  all  UWB  devices,  emission  limits  below  960  MHz  are  based  on  the  use  of  a  CISPR  quasi-  peak  detector  and  average  emissions  above  960  MHz  are  based  on  the  use  of  an  RMS  average 
 detector  with  a  1  MHz  resolution  bandwidth.  For  systems  operating  above  960  MHz,  there  is  a  limit  on  the  peak  emission  level  contained  within  a  50  MHz  bandwidth  centered  on  the  frequency,  fM,  at  which  the 
 highest  radiated  emission  occurs.  That  limit  is  0  dBm  EIRP.  A  different  resolution  bandwidth  of  between  1  MHz  and  50  MHz  may  be  employed  for  the  peak  measurement  provided  the  peak  EIRP  level  does  not 
 exceed  20  log  (RBW/  50)  dBm  where  RBW  is  the  resolution  bandwidth  in  megahertz.  Only  one  peak 
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 measurement,  centered  on  fM,  is  required.  If  the  UWB  transmitter  connects  to  the  AC  power  lines,  there  is  a  quasi-  peak  limit  of  250  uV  over  the  frequency  range  of  450  kHz  to  30  MHz.  336 
 F.  Cumulative  Impact 
 226.  Proposal.  While  the  Commission  indicated  that  further  testing  and  analysis  is  desirable  on  this  issue,  it  stated  in  the  Notice  that  it  appeared  that  cumulative  impact  is  negligible  at  the  power 

 levels  and  with  the  modulation  types  being  proposed,  especially  when  compared  to  the  interference  potential  from  a  single  land  mobile  transmitter.  Thus,  the  Commission  believed  that  only  the  closest 
 transmitter  placing  an  emission  on  the  frequency  of  concern  would  be  of  importance,  obviating  the  need  for  additional  attenuation  to  compensate  for  cumulative  effects.  However,  it  added  that  the  cumulative 
 impact  of  several  UWB  devices  might  be  different  depending  on  their  individual  emission  and  transmission  characteristics.  For  example,  how  does  the  cumulative  impact  of  those  UWB  transmitters 
 that  emit  a  line  spectrum  compare  to  those  that  have  a  high  level  of  random  pulse  positioning  or  dithering  and  may  appear  as  Gaussian  noise?  337  Further,  what  is  the  relationship  between  pulse  repetition 
 frequency  and  the  cumulative  impact  of  a  number  of  UWB  devices?  The  Commission  noted  that  the  emission  limits  were  established  based  on  the  potential  interference  from  a  single  Part  15  device  and  do 
 not  take  into  account  cumulative  effects  that  could  occur  if  a  number  of  devices  are  located  closely  together.  Comments  and  test  data  were  requested  along  with  relevant  input  from  the  Commissions 
 Technical  Advisory  Council. 
 227.  Comments.  There  was  no  agreement  among  the  comments.  It  is  obvious  that  emissions  from  multiple  UWB  transmitters  are  additive  to  some  extent.  As  the  UWB  emissions  become  more  noise 

 like,  they  tend  to  add  directly,  as  would  be  expected  with  noise  emissions.  This  was  demonstrated  in  the  University  of  Texas  tests  using  multiple  UWB  transmitters.  338  Other  commenting  parties  have  advanced 
 various  mathematical  models  of  UWB  system  configurations  to  demonstrate  whether  the  major  impact  is  caused  by  the  closest  UWB  emitter  or  is  caused  by  the  cumulative  effect  of  all  surrounding  emitters. 

 228.  XSI  argued  that  there  is  little  cumulative  effect  from  multiple  UWB  devices  even  when  they  are  concentrated  in  a  small  area.  339  XSI  added  that  UWB  devices  could  not  add  over  distances 
 greater  than  about  10  meters  because  of  poor  indoor  propagation.  340  XSI  noted  that  devices  located  within  about  10  m  of  each  other  share  a  common  RF  channel  and  so  must  reduce  power,  duty  cycle,  or 
 both  to  avoid  mutual  interference.  As  stated  by  Aether  Wire,  a  local  network  of  UWB  devices  will  generally  have  only  one  device  transmitting  at  any  time.  341  Similarly,  Sprint  PCS  stated  that  many  types 
 of  UWB  devices  will  not  transmit  continuously,  but  rather  will  transmit  burst  or  packets  as  necessary.  342  Sprint  PCS  added  that  in  that  case  it  would  not  be  realistic  to  sum  interference  contributions  from 
 multiple  UWB  transmitters  that  normally  would  not  all  be  transmitting  simultaneously. 
 229.  Motorola  stated  that  it  expected  that  the  UWB  devices  closest  to  the  victim  receiver 
 336  This  limit  could  change  in  the  future  based  on  the  Notice  of  Proposed  Rule  Making  in  ET  Docket  No.  98-80, 
 supra.  337 
 Most  UWB  transmitters  produce  a  line  spectrum  while  those  employing  high  levels  of  random  pulse  positioning  can  appear  more  as  Gaussian  noise.  For  the  former  devices,  the  emission  only  appears  as  noise 

 depending  on  the  settings  of  the  measurement  instrumentation.  338 
 See  TDC  submission  of  3/  9/  01,  supra.  339 
 XSI  ex  parte  response  of  7/  25/  01  at  pg.  3-  4  and  5-  6.  340 
 XSI  was  promoting  an  indoor-  only  system.  341 
 Aether  Wire  comments  at  pg.  12.  342 
 Sprint  PCS  comments  at  Attachment  1,  pg.  1-  2. 
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 would  dominate  due  to  typical  path  losses.  343  Its  Monte  Carlo  analysis  demonstrated  that  the  vast  majority  of  the  time  more  than  90  percent  of  the  interference  is  coming  from  the  closest  one  to  five  UWB 
 transmitters.  Thus,  Motorola  concluded  that  even  with  1000  surrounding  transmitters  the  effect  of  cumulative  interference  was  not  as  severe  as  the  effect  from  the  closest  transmitters.  Motorolas  analysis 
 found  that  a  cumulative  effect  was  more  prevalent  where  the  victim  receiver  was  a  base  station  with  no  nearby  UWB  transmitters.  Under  this  condition,  it  took  a  considerably  greater  number  of  transmitters  to 
 contribute  90  percent  of  the  interference  power,  using  UWB  emission  contributions  from  as  far  away  as  600  m.  344  As  stated  by  AT&  T,  the  important  issue  is  how  many  transmitters  operating  simultaneously 
 within  a  specified  range  will  cause  an  additive  power  problem.  345 
 230.  NTIA  employed  a  mathematical  analysis  using  successive,  equally  spaced  rings  containing  UWB  emitters  with  their  energy  maximized  in  the  direction  of  the  victim  receiver  to 

 demonstrate  that  high  concentrations  of  UWB  transmitters  could  result  in  cumulative  interference.  346  However,  XSI  demonstrated  that  if  only  one  UWB  transmitter  was  placed  within  the  inner  ring  used  in 
 NTIAs  analysis  the  emission  from  that  single  UWB  transmitter  would  dominate  the  signal  at  the  victim  receiver. 

 231.  DOD  provided  mathematical  analyses  of  possible  cumulative  interference  from  UWB  operation  to  its  SEEK  Skyhook  radar  system,  operating  at  3.15  GHz  and  at  3.23  GHz.  347  The  SEEK 
 Skyhook  is  a  surveillance  radar  positioned  12,000  feet  above  mean  sea  level  operating  with  a  range  of  278  km  at  an  altitude  of  3660  meters.  It  currently  is  used  to  detect  low  flying  aircraft  for  drug  interdiction  at 
 Cudjoe  Key,  Florida  and  operates  with  a  narrow  40  dBi  antenna  tilted  at  1.5  degrees.  Based  on  these  specifications,  DOD  calculated  the  ground  area  illuminated  by  the  radar  antenna  and  the  distance  to  the 
 center  of  that  range  to  determine  how  many  UWB  emitters  could  be  permitted  per  square  kilometer  based  on  I/  N  levels  ranging  from  3  dB  to  10  dB.  348  It  concluded  that  a  UWB  emission  level  of  53  dBm 
 covers  most  of  the  interference  situations  it  analyzed  and  that  mitigating  factors  from  UWB  antenna  patterns,  intermittent  operation,  building  attenuation,  and  obstacle  attenuation  would  permit  a  higher 
 signal  level. 
 232.  ARRL  stated  that  while  more  distant  radiators  would  create  less  noise,  this  would  be  offset  by  the  fact  that  there  are  more  of  them  seen  by  the  victim  receiver.  349  It  added  that  the  large 

 antennas  used  by  amateur  operators  at  UHF  and  higher  frequencies  would  see  a  cumulative  effect  when  overlooking  urban  areas.  ARRL  added  that  a  single  UWB  emitter  may  dominate  if  the  interference 
 extended  only  for  tens  of  meters,  but  as  demonstrated  by  Motorola  the  interference  could  extend  for  hundreds  of  meters.  350  TDC  argued  that  the  closest  UWB  transmitter  would  produce  the  greatest  impact 
 as  signals  from  more  distant  devices  would  be  subsumed  by  the  noise  floor. 
 233.  Discussion.  We  agree  with  ARRL  that  a  single  UWB  emitter  will  dominate  if  the 

 343  Motorola  comments  at  pg.  10  and  20-  21. 
 344  Motorola  comments  at  pg.  26-  27. 
 345  AT&  T  comments  at  pg.  6. 
 346  NTIA  Special  Publication  01-  43,  supra,  at  pg.  5-  1  through  5-  34  and  B-  1  through  B-  27. 
 347  Filing  of  U.  S.  Department  of  Defense  submitted  10/  1/  00,  Attachment  1. 
 348  We  believe  that  the  power  levels  being  permitted  for  UWB  operation  would  need  to  be  considerably  higher 
 in  order  to  transverse  the  hundreds  of  kilometers  necessary  to  cause  interference  to  the  DOD  SEEK  Skyhook  radar  system. 

 349  ARRL  comments  at  pg.  13-  14. 
 350  ARRL  reply  comments  at  pg.  8. 
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 interference  extends  for  only  a  few  tens  of  meters.  Earlier  in  this  Report  and  Order,  we  demonstrated  that  the  interference  impact  of  a  single  UWB  device  is  on  the  order  of  tens  of  meters  or  less  with  the 
 exception  of  a  few  sensitive  receivers  that  operate  at  the  noise  floor  and  employ  high  gain  antennas,  such  as  the  ARSR-  4  system.  351  The  ARSR-  4  would  not  be  particularly  prone  to  cumulative  interference  as  it 
 views  only  a  narrow  ground  segment  at  any  given  time.  352  Systems  prone  to  receiving  cumulative  interference  are  those  that  employ  high  gain  receiving  antennas  directed  over  large  geographical  areas. 
 Examples  are  airborne  systems  and  receivers  located  on  orbiting  satellites.  Wide  coverage  area  cellular  and  PCS  base  stations  also  may  experience  some  cumulative  impact  although  it  should  be  considerably 
 less  than  that  received  by  airborne  receivers. 
 234.  We  have  implemented  considerable  restraints  on  the  technical  and  operational  standards  for  UWB  equipment  to  ensure  that  cumulative  interference  will  not  occur.  Primarily,  we  have  limited 

 outdoor  applications  to  imaging,  hand  held  and  vehicle  radar  systems.  The  directional  antennas  employed  by  imaging  and  vehicle  radar  systems  make  it  unlikely  that  the  maximum  emission  components  would  be 
 directed  towards  a  victim  receiver.  Thus,  directional  antennas  prevent  the  occurrence  of  multiple  UWB  emitters  from  producing  equally  received  emission  levels  even  if  they  are  equally  distant  from  the  victim 
 receiver.  Also,  the  majority  of  the  UWB  radar  devices  being  authorized  direct  their  emissions  into  the  ground  or  horizontally,  away  from  airborne  or  satellite  receivers.  In  addition,  limiting  the  applications  to 
 systems  that  operate  at  ground  level  353  ensures  that  the  emissions  attenuate  more  rapidly  with  distance  and  have  a  higher  probability  of  obstructions  between  the  UWB  transmitter  and  the  victim  receiver.  Most  of 
 the  imaging  UWB  devices  will  operate  only  infrequently  and  will  be  far  apart  such  that  it  is  unlikely  they  will  cause  any  cumulative  effect.  We  also  implemented  constraints  on  the  frequency  bands  in  which  the 
 equipment  is  permitted  to  operate.  Limiting  devices  to  operate  above  certain  frequency  bands  ensures  that  the  maximum  emissions  will  not  occur  in  lower  frequency  bands  where  greater  propagation  may 
 occur.  Finally,  we  required  UWB  devices  to  operate  at  reduced  emission  levels  between  960  MHz  and  1990  MHz  or  higher,  significantly  reducing  the  range  over  which  the  UWB  emissions  in  this  band  can  be 
 detected.  All  of  these  features  combine  to  ensure  that  UWB  systems  will  not  result  in  a  cumulative  interference  problem.  While  it  is  possible  that  indoor  UWB  devices,  operating  in  an  omnidirectional 
 mode,  could  be  sufficiently  concentrated  in  a  small  area  to  cause  a  cumulative  effect,  XSI,  Sprint  PCS  and  others  have  already  demonstrated  that  these  devices  will  not  operate  simultaneously.  354  It  is  more  likely 
 that  any  high  concentration  of  UWB  devices  operating  indoors  would  be  an  interlinked  system  with  a  low  overall  duty  cycle  so  as  to  avoid  mutual  interference. 

 G.  Measurement  Procedures 
 235.  In  the  Notice,  we  proposed  to  continue  to  employ  quasi-  peak  measurements  for  emissions  below  1  GHz  and  average  and  peak  measurements  for  emissions  above  1  GHz,  as  under  the  current 

 rules.  355  Quasi-  peak  measurements  provide  a  weighted  average  over  a  specified  measurement  bandwidth  while  average  measurements  above  1  GHz  are  based  on  the  use  of  a  1  MHz  resolution  bandwidth 
 (  RBW).  Comments  were  sought  regarding  the  specific  measurement  procedures  that  should  be 

 351  Interference  to  systems  such  as  the  ARSR-  4  has  been  sufficiently  addressed  through  the  emission  limits 
 being  adopted  in  this  proceeding.  352 
 The  directional  signal  characteristics  of  the  UWB  systems  also  will  reduce  the  number  of  UWB  devices  visible  to  the  ARSR-  4  receiver. 

 353  We  expect  that  most  handheld  devices  would  be  operated  indoors  or  at  ground  level. 
 354  As  noted  earlier,  it  will  appear  to  outdoor  receivers  that  indoor  UWB  systems  are  operating  with  directional 
 antennas  due  to  variable  attenuation  from  building  walls  and  randomly  placed  obstacles  within  the  building.  355 
 See  47  C.  F.  R.    15.35(  b)  and  15.209(  d).  There  are  also  certain  rule  sections  that  specify  the  application  of  a  total  peak  power  limit  over  a  wider  bandwidth.  See,  for  example,  47  C.  F.  R.    15.247(  b)  and  15.255(  e). 
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 employed. 
 1.  Quasi-  peak  and  Average  Measurements 
 236.  For  measuring  average  emissions,  we  proposed  in  the  Notice  that  spectrum  analyzer  video  averaging  with  a  video  bandwidth  ("  VBW")  of  no  greater  than  10  kHz  or  less  than  10  Hz  be  used  in 

 conjunction  with  peak  hold  to  determine  the  average  level  as  a  function  of  frequency.  Alternative  techniques  that  can  be  shown  to  give  comparable  or  more  accurate  results  would  be  considered. 
 Comments  were  requested  on  applying  the  measurement  procedures  specified  in  HP  Application  Note  150-  2.  Under  this  note,  if  there  was  no  dithering  of  the  pulse  position  or  pulse  position  modulation,  the 
 average  level  of  the  fundamental  and  harmonic  emissions  would  be  measured  using  a  spectrum  analyzer  adjusted  to  produce  a  line  spectrum  with  the  VBW  equal  to  or  greater  than  the  RBW.  This  requires  that 
 the  RBW  be  less  than,  or  equal  to,  0.3  times  the  pulse  repetition  frequency.  The  level  of  the  highest  line  in  the  emission  line  spectrum  being  measured  would  be  the  average  level.  If  the  dithering  or  pulse  position 
 modulation  could  not  be  turned  off,  the  emission  would  be  measured  with  the  spectrum  analyzer  settings  adjusted  to  obtain  a  true  pulse  spectrum.  A  pulse  desensitization  correction  factor,  based  on  the 
 calculations  provided  in  HP  Application  Note  150-  2,  would  be  added  to  the  measurement  to  obtain  a  peak  level,  and  the  average  would  be  calculated  using  the  duty  cycle  factor  in  dB. 

 237.  Comments.  Quasi-  peak  and  average  emission  measurements  are  well  understood,  and  ANSI  356  and  others  have  established  appropriate  measurement  procedures.  ANRO,  Bosch  and  Zircon 
 supported  the  proposed  average  measurement  techniques.  357  There  were,  however,  several  requests  for  variations  from  our  measurement  procedures.  NTIA  requested  that  we  apply  an  average  limit  based  on  an 
 RMS  average  rather  than  a  logarithmic  average,  such  as  would  be  obtained  from  a  spectrum  analyzer  employing  a  low  video  bandwidth.  358  It  stated  that  the  average  logarithm  is  largely  insensitive  to  energy 
 contained  in  low  duty  cycle,  high  amplitude  signals.  It  added  that  no  single  average  detector  function  adequately  describes  the  interference  effects  of  UWB  signals  but  the  RMS  average  better  quantifies  this. 
 NTIA  also  wished  to  apply  the  average  emission  limits  above  960  MHz  instead  of  1000  MHz.  359 
 238.  On  the  other  hand,  Lucent  requested  that  the  VBW  employed  for  an  average  measurement  be  greater  than  10  Hz  because  of  the  possibility  of  burst  transmissions.  360  Lucent  was 

 concerned  that  a  10  Hz  VBW,  approximating  averaging  over  a  100  millisecond  period,  would  result  in  too  low  a  measured  value,  permitting  the  actual  radiated  emission  to  exceed  our  average  limits.  Lucent 
 requested  that  the  VBW  be  set  no  lower  than  10  kHz  or  that  an  undefined  correction  factor  be  applied  when  the  transmitter  operating  time  was  less  than  the  averaging  time  of  the  measurement.  Metricom 
 requested  that  average  measurements  be  made  using  a  RBW  of  50  MHz,  just  like  the  peak  measurements.  361  A  narrower  VBW  would  be  employed  to  average  the  emission. 

 239.  Most  of  the  comments  were  directed  not  towards  the  actual  measurement  instrumentation 
 356  American  National  Standards  Institute  (ANSI)  ANSI  C63.  4-  1992,  Methods  of  Measurement  of  Radio-  Noise 
 Emissions  from  Low-  Voltage  Electrical  and  Electronic  Equipment  in  the  Range  of  9  kHz  to  40  GHz,  is  specified  in  the  Part  15  regulations  as  the  measurement  procedure  applicable  to  Part  15  devices.  See  47  C.  F.  R.    15.  31(  a)(  6). 

 357  ANRO  comments  at  pg.  2;  Bosch  comments  at  pg.  5;  Zircon  comments  at  pg.  4. 
 358  See  NTIA  Report  01-  383,  supra,  at  pg.  6-  18  through  6-  25  and  A-  1  through  A-  21.  See,  also,  NTIA  Special 
 Publication  01-  43,  supra,  at  pg.  2-  1  through  2-  2.  359 
 One  of  the  U.  S.  Government  frequency  bands  starts  at  960  MHz,  not  at  1000  MHz.  360 
 Lucent  comments  at  pg.  3.  Burst  transmissions  are  extremely  short  transmission  intervals  that  have  a  low  average  emission  level. 

 361  Metricom  comments  at  pg.  5. 
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 settings  but  to  the  test  setup  itself.  With  regard  to  GPRs,  A.  Peter  Annan  expressed  concern  that  GPRs  may  not  be  perfectly  coupled  with  the  ground,  suggesting  that  the  GPRs  be  measured  while  suspended  in 
 the  air  and  20  to  40  dB  be  subtracted  from  the  results.  362  Mr.  Annan  also  requested  that  GPRs  operating  below  250  MHz  be  measured  with  a  resistive  load  substituted  for  the  antenna.  CSSIP  requested  that 
 GPRs  be  measured  with  the  antennas  in  contact  with,  or  in  close  proximity  to,  the  ground  using  a  suitable  media  of  dry  sand,  freshwater,  salty-  water  or  concrete  made  from  specified  materials.  363  An  ex  parte 
 filing  by  Sensors  &  Software  and  GSSI  requested  the  use  of  a  concrete  slab,  at  least  8  inches  thick,  the  size  of  the  GPR  transducer  and  installed  over  12  inches  of  gravel,  be  used  as  the  absorptive  material  for  a 
 GPR.  364  No  metal  or  fiberglass  reinforcing  bar  would  be  used  in  this  base  material. 
 240.  TDC  also  suggested  several  provisions  for  the  test  set-  up  for  UWB  measurements.  365  TDC  requested  that  we  permit  measurements  at  1  meter  due  to  the  need  for  the  measured  emission  to  be 

 at  least  10  dB  above  the  noise  level  of  the  spectrum  analyzer  for  accuracy  purposes.  Bosch  suggested  the  use  of  a  corrugated  horn  antenna  for  measuring  emissions  above  1  GHz  as  these  antennas  have  a  fixed 
 phase  center  and  may  be  used  over  a  wide  bandwidth.  366 
 241.  Discussion.  There  is  no  apparent  difficulty  in  performing  measurements  of  quasi-  peak  or  average  emission  levels.  Such  procedures  are  well  documented  in  the  current  FCC  test  procedures  and 

 the  application  notes  published  by  spectrum  analyzer  manufacturers.  There  are,  however,  a  few  areas  where  we  need  to  provide  clarification  of  the  measurement  procedures.  A  measurement  procedure 
 applicable  to  UWB  devices  is  attached  as  Appendix  F.  The  following  discussion  provides  the  reasons  for  several  of  the  features  we  are  including  in  these  procedures.  367 

 242.  We  concur  with  NTIAs  request  that  logarithmic  averaging  not  be  permitted  for  UWB  average  measurements.  We  currently  do  not  permit  a  logarithmic  average  to  be  employed  for  any  Part  15 
 measurements  with  one  exception:  if  the  peak-  to-  average  ratio  of  an  emission  is  low  and  the  measured  emission  is  well  below  our  limits,  we  have  permitted  the  use  of  logarithmic  averaging  in  order  to  facilitate 
 measurements.  While  we  normally  perform  measurements  of  emissions  from  Part  15  devices  with  the  detector  on  the  spectrum  analyzer  set  in  the  linear  mode  368  ,  we  recognize  that  the  test  data  and  analyses  in 
 this  proceeding  were  performed  based  on  RMS  average  emission  levels.  In  keeping  with  our  conservative  approach  to  implementing  UWB  operation,  we  are  adopting  NTIAs  suggestion  to  specify  the  average 
 emission  limits  in  terms  of  RMS  average.  A  1  MHz  resolution  bandwidth  would  be  employed  with  an  RMS  detector  and  an  averaging  time  of  1  millisecond  or  less.  Appendix  F  also  describes  an  alternative 
 method  that  can  be  used  to  measure  RMS  average  emission  levels  using  spectrum  analyzers  that  do  not  have  an  RMS  detector.  We  also  are  implementing  NTIAs  request  to  begin  RMS  average  emission  limits, 
 based  on  the  use  of  a  1  MHz  resolution  bandwidth,  beginning  at  960  MHz. 
 243.  We  do  not  agree  with  Lucent  that  a  minimum  VBW  of  10  kHz  needs  to  be  established  369  or  that  a  correction  factor  needs  to  be  applied  to  average  emission  measurements  of  short  burst 

 362  A.  Peter  Annan  comments  at  pg.  7-  8. 
 363  CSSIP  comments  at  pg.  2. 
 364  Sensors  &  Software  and  GSSI  ex  parte  filing  of  10/  10/  01. 
 365  TDC  comments  at  pg.  36-  42  and  reply  comments  at  pg.  59. 
 366  Bosch  comments  at  pg.  5. 
 367  We  noted  under  the  discussion  on  emission  limits  the  need  to  test  for  narrowband  emission  levels  in  the 
 GPS  frequency  bands  and  the  test  procedure  that  would  be  applied.  368 
 Linear  averaging  can  be  accomplished  by  using  appropriate  video  averaging  or  by  trace  averaging.  369 
 It  is  not  necessary  to  specify  a  video  bandwidth  with  an  RMS  detector. 
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 transmissions.  Lucent  has  not  provided  any  information  to  demonstrate  why  the  application  of  a  10  Hz  VBW,  representing  an  averaging  period  of  100  milliseconds,  to  a  burst  UWB  transmission  would  result  in 
 a  higher  interference  potential.  We  agree  that  burst  transmissions  would  have  a  low  average  measurement  because  of  their  short  period  of  operation.  However,  the  peak  levels  we  are  establishing  would  limit  such 
 transmissions.  A  UWB  system  with  a  high  peak-  to-  average  ratio  would  be  peak-  limited,  resulting  in  the  measured  average  emission  level  being  well  below  our  limits.  We  also  reject  the  proposal  by  Metricom  to 
 employ  a  50  MHz  RBW  for  average  measurements.  Metricom  did  not  provide  any  justification  as  to  why  such  a  large  RBW  is  necessary  for  average  measurements.  It  appears  that  Metricom  wanted  the  use  of  a 
 wider  RBW,  without  a  corresponding  increase  in  permitted  signal  level,  solely  to  reduce  the  levels  of  the  radiated  emissions.  We  also  note  that  measurement  equipment  employing  such  a  wide  RBW  is  not 
 commonly  available  in  laboratory  environments,  and  we  are  unsure  about  the  repeatability  of  measurements  made  using  such  equipment. 

 244.  In  most  cases,  measurements  will  follow  the  procedures  specified  in  47  C.  F.  R.  15.31(  a)(  6).  However,  we  believe  that  the  measurement  procedures  applied  to  UWB  devices  also  should 
 address  the  manner  in  which  the  equipment  is  designed  to  be  operated.  For  example,  through-  wall  imaging  systems  are  intended  to  transmit  through  a  wall  that  may  not  dissipate  much  of  the  energy.  Thus, 
 these  systems  may  be  tested  with  a    inch  section  of  gypsum  board  in  front  of  the  transmitting  antenna.  No  attenuating  material  would  be  employed  in  front  of  medical  imaging  systems,  vehicle  radar  systems, 
 indoor  systems,  or  hand  held  devices.  370  On  the  other  hand,  GPRs  and  wall  imaging  systems  are  designed  to  dissipate  their  transmitted  energy  into  the  ground  or  other  structure  into  which  they  are  radiating. 
 Testing  these  devices  over  a  ground  plane  would  cause  the  transmitted  energy  to  be  reflected  back  into  the  air.  Thus,  we  agree  with  CSSIP,  Sensors  &  Software  and  GSSI  that  GPRs  and  wall  imaging  systems 
 should  be  tested  over  an  absorptive  material.  We  are  specifying  that  the  transmitted  emission  from  a  GPR  or  a  wall  imaging  system  is  to  be  directed  towards  20  inches  of  dry  sand.  We  believe  that  the  use  of 
 dry  sand  will  be  easier  to  establish  than  a  concrete/  gravel  test  bed  and  would  not  contain  the  discontinuity  at  8  inches  as  would  occur  with  the  concrete/  gravel  interface.  This  dry  sand  bed  shall  be  at  least  the  width 
 and  length  of  the  GPR  or  wall  imaging  system  being  tested.  Further,  no  ground  plane  shall  be  located  under  this  dry  sand  bed.  GPRs  shall  be  suspended  above  this  material  at  the  height  above  ground  at 
 which  the  equipment  is  intended  to  operate.  Wall  imaging  systems  shall  be  suspended  above  this  material  at  the  separation  distance  at  which  they  are  intended  to  operate  from  a  wall.  Recognizing  that  the  use  of 
 this  absorptive  material  will  prevent  the  use  of  a  turntable,  measurements  must  be  taken  at  a  sufficient  number  of  radials  to  ensure  that  the  measured  emission  levels  are  maximized. 

 245.  Because  of  the  lack  of  ground  plane  material  in  the  test  bed  used  for  GPRs  and  wall  imaging  systems,  we  are  establishing  a  test  procedure  than  may  be  used  for  any  UWB  device  as  an  option 
 to  using  a  ground  plane.  We  will  permit  RF  absorptive  material,  such  as  that  found  in  an  anechoic  chamber,  to  be  employed  between  the  equipment  under  test  and  the  measuring  instrumentation. 
 However,  if  this  absorptive  material  is  used  4.7  dB  must  be  added  to  the  obtained  measurement  results  to  simulate  the  effect  of  an  additive  signal  reflected  from  the  ground  plane.  In  addition,  measurements  may 
 be  made  at  a  closer  distance,  as  requested  by  TDC,  following  the  existing  procedures  in  47  C.  F.  R.    15.31(  f).  However,  measurements  may  not  be  made  in  the  near  field. 

 2.  Peak  Measurements 
 246.  Proposal.  In  the  Notice,  we  recognized  that  the  measurement  of  peak  power  based  on  a  50  MHz  measurement  bandwidth  can  not  be  performed  with  normal  commercial  EMC  test  equipment. 

 We  noted  that  microwave  receivers  designed  for  radar  interception  and  analysis  are  available  with  such  characteristics  and  have  costs  comparable  to  normal  EMC  test  equipment.  Further,  the  IF  output  of  a 

 370  The  type  of  material  in  front  of  these  transmitters,  if  any,  could  vary.  Thus,  no  attempt  was  made  to 
 categorize  this  material. 
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 microwave  receiver  that  uses  a  wide  bandwidth,  e.  g.,  50  MHz,  could  be  analyzed  using  a  conventional  oscilloscope  in  order  to  measure  the  peak  level  of  the  waveform  in  the  time  domain.  Comments  were 
 sought  on  the  feasibility  of  this  testing  technique  as  well  as  its  utility  as  a  model  for  the  interference  potential  of  peak  UWB  levels.  As  we  are  not  adopting  a  standard  for  total  peak  power,  there  is  no  need  to 
 discuss  a  corresponding  measurement  procedure.  371  Similarly,  there  is  no  need  to  reiterate  the  discussion  on  antennas  suitable  for  extreme  bandwidth  measurements. 

 247.  Comments/  Discussion.  Several  of  the  comments  responded  to  the  systematic  problems  of  measuring  a  peak  emission  level  over  a  50  MHz  bandwidth.  TDC  supplied  a  detailed  measurement 
 procedure  for  accomplishing  this.  372  We  appreciate  the  efforts  of  the  commenting  parties.  Unfortunately,  upon  reflection  we  do  not  believe  that  peak  measurements  employing  a  50  MHz  bandwidth  are  practical 
 using  currently  available  equipment.  As  has  become  obvious  from  the  comments,  there  are  considerable  difficulties  maintaining  phase  accuracy  over  a  50  MHz  bandwidth  making  calibration  of  the  setup  of  the 
 test  bed  and  the  measurements  of  the  radiated  emissions  difficult.  Further,  the  choice  of  the  variable-frequency  filter  used  to  perform  measurements  over  a  50  MHz  bandwidth  is  extremely  critical.  It  is 
 unlikely  that  measurements  over  a  50  MHz  bandwidth  would  be  repeatable  from  one  test  site  to  another. 
 248.  Siemens  suggested  measuring  the  peak  emission  level  using  the  maximum  RBW  available  on  the  instrumentation  and  calculating  the  peak  emission  at  50  MHz.  373  Valeo  proposed  a 

 method  of  integrating  a  measurement  from  a  spectrum  analyzer  over  50  MHz.  374  As  stated  by  Fantasma,  the  existing  rules  employing  a  1  MHz  RBW  are  simple  and  straight  forward.  375  While  USGPSIC  argued 
 against  the  use  of  a  spectrum  analyzer,  stating  that  spectrum  analyzers  sample  at  too  low  a  rate  to  capture  the  peak  power  of  UWB  signals  376  ,  we  believe  that  a  spectrum  analyzer  can  provide  a  realistic  view  of  the 
 peak  emission  level  as  it  would  be  viewed  by  a  receiver  employing  a  similar  bandwidth. 
 249.  We  believe  that  there  is  a  simpler  method  of  measuring  peak  emission  levels  in  a  manner  that  also  takes  into  account  the  interference  potential  of  the  equipment.  In  order  to  perform  a  peak 

 measurement  on  a  spectrum  analyzer,  the  VBW  must  be  at  least  as  large  as  the  RBW.  The  largest  VBW  on  a  spectrum  analyzer  is  about  7  MHz.  Thus,  the  widest  RBW  that  could  be  employed  is  3  MHz. 
 However,  there  are  several  receivers  used  by  the  authorized  radio  services  that  employ  greater  bandwidths.  Thus,  the  concern  is  how  to  ensure  that  peak  measurements  performed  with  a  3  MHz  RBW 
 will  protect  receivers  that  employ  a  wider  bandwidth  from  harmful  interference. 
 250.  Appendix  E  attached  to  this  Report  and  Order  demonstrates  the  theoretical  peak-  to-average  relationship  of  a  pulsed  emission  and  a  dithered  emission  that  appears  like  Gaussian  noise  as  the 

 PRF  is  varied.  In  these  graphs,  the  average  is  based  on  measurements  performed  with  a  1  MHz  RBW.  The  peak  measurements  are  based  on  measurements  performed  with  a  RBW  of  1  MHz,  3  MHz  and  50 
 MHz.  As  can  be  seen,  the  major  differences  between  changes  in  RBW  are  not  based  on  a  10  log  relationship.  Rather,  they  are  based  on  a  20  log  relationship.  377  We  established  a  peak  emission  limit  of  0 
 dBm  as  measured  over  a  50  MHz  bandwidth.  Under  these  conditions,  reducing  the  RBW  from  50  MHz 

 371  The  comments  noted  considerable  difficulties  in  attempting  to  measure  total  peak  output  levels.  See,  for 
 example,  TDC  comments  at  pg.  42-  43.  372 
 TDC  reply  comments  at  Appendix  C.  373 
 Siemens  comments  at  pg.  1.  374 
 Valeo  comments  at  pg.  12.  375 
 Fantasma  reply  comments  at  pg.  9.  376 
 USGPSIC  comments  at  pg.  45,  footnote  81.  377 
 The  worst  case  comparison  occurs  when  the  PRF  is  less  than  RBW/  0.  45. 
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 to  3  MHz  results  in  an  attenuation  of  the  peak  limit  of  20  log  (3/  50)  or  24.44  dBm.  378  Reducing  the  allowed  peak  limit  to  an  EIRP  of  24.44  dBm  when  measured  with  a  3  MHz  RBW  ensures  that  the 
 emission  would  be  no  greater  than  0  dBm  if  it  was  measured  with  a  50  MHz  RBW.  Peak  measurements  using  a  spectrum  analyzer  with  a  3  MHz  RBW  are  relatively  straight-  forward  and  can  be  performed  using 
 existing  measurement  procedures.  It  also  is  expected  that  these  measurements  should  be  reproducible  between  different  measurement  sites.  For  these  reasons,  we  are  adopting  a  peak  measurement  procedure 
 employing  a  3  MHz  resolution  bandwidth.  This  measurement  must  be  performed  centered  on  the  frequency  of  emission  on  which  appears  the  highest  average  level  emission. 

 251.  As  stated  earlier,  our  conversion  from  a  50  MHz  resolution  bandwidth  to  a  3  MHz  resolution  bandwidth  is  based  on  the  worse  case  assumption  that  changes  in  the  peak  levels  changes 
 follow  the  square  of  the  change  in  the  resolution  bandwidth.  That  is,  the  change  in  the  allowable  peak  limit  at  50  MHz  to  a  peak  limit  at  3  MHz  was  based  on  20  log  (3/  50)  dB.  We  also  recognized  that  this 
 could  penalize  some  UWB  operations,  particularly  those  operating  with  PRFs  greater  than  around  6.7  MHz.  To  compensate  for  this,  peak  limits  were  established  based  on  a  sliding  scale  that  is  dependent  on 
 the  actual  resolution  bandwidth  employed  in  the  measurement.  The  peak  EIRP  limit  is  20  log  (RBW/  50)  dBm  when  measured  with  a  resolution  bandwidth  between  1  MHz  and  50  MHz.  379  RBW  is  the  resolution 
 bandwidth  in  megahertz  actually  employed.  This  bandwidth  must  be  centered  on  the  frequency  at  which  the  highest  radiated  emission  occurs. 

 252.  We  intend  to  employ  at  our  laboratory  a  measurement  procedure  using  a  3  MHz  resolution  bandwidth.  However,  we  will  permit  responsible  parties  to  test  their  UWB  products  using 
 different  resolution  bandwidths  ranging  from  1  MHz  to  as  high  as  50  MHz.  The  use  of  a  higher  resolution  bandwidth  may  be  particularly  helpful  for  measuring  a  system  operating  at  a  higher  PRF.  If  a  resolution 
 bandwidth  greater  than  3  MHz  is  employed,  the  application  for  certification  filed  with  the  Commission  must  contain  a  detailed  description  of  the  test  procedure,  calibration  of  the  test  setup,  and  the 
 instrumentation  employed  in  the  testing. 
 3.  Frequency  Range  of  Measurement 
 253.  Proposal.  For  impulse  systems,  the  Commission  proposed  that  the  center  frequency  of  the  emission  bandwidth,  as  determined  by  the  10  dB  points,  should  be  used  as  the  reference  for 

 determining  the  upper  frequency  range  over  which  emissions  should  be  measured.  380  Noting  that  the  emission  spectrum  will  change  depending  on  the  specific  measurement  procedures  employed,  e.  g.,  the  use 
 of  average  versus  peak  measurements,  comments  were  requested  on  any  specific  measurement  procedures  that  should  be  employed  to  determine  the  center  frequency.  For  a  carrier  modulated  system,  the 
 Commission  proposed  that  the  carrier  frequency  should  continue  to  be  used  as  the  reference  for  determining  the  upper  frequency  range  over  which  emissions  should  be  measured.  However,  the 
 Commission  expressed  concern  that  a  manufacturer  could  employ  a  low  frequency  carrier  with  an  extremely  narrow  pulse  or  a  narrow  pulse  impulse  system  could  be  used  with  a  low  frequency  antenna, 
 resulting  in  emissions  extending  far  beyond  the  tenth  harmonic,  the  normal  upper  range  of  measurement.  Accordingly,  comments  were  requested  on  whether  a  different  method  of  determining  the  frequency 
 measurement  range  should  be  employed,  e.  g.,  a  system  based  on  pulse  rise  time  and  width.  In  addition,  it  was  noted  that  the  lower  frequency  range  of  measurements  would  continue  to  be  determined  by  the  lowest 

 378  If  peak  measurements  were  to  be  performed  using  a  1  MHz  bandwidth,  the  peak  limit  would  be  decreased 
 by  20  log  (1/  50)  or  to  an  EIRP  of  34  dBm.  379 
 This  may  be  converted  to  a  peak  field  strength  level  at  3  meters  using  E(  dBuV/  m)  =  P(  dBm  EIRP)  +  95.  2.  380 
 While  several  references  to  the  20  dB  emission  points  were  made  in  the  comments  for  defining  UWB  emissions,  we  believe  that  the  10  dB  emissions  points  are  more  appropriate  for  determining  the  center  frequency  as 

 it  is  unlikely  that  the  10  dB  points  would  be  below  the  noise  floor  of  a  spectrum  analyzer. 
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 radio  frequency  generated  in  the  device.  Comments  were  requested  on  whether  the  pulse  repetition  frequency,  pulse  dithering  frequency,  modulating  frequency  or  other  factors  would  permit  the 
 investigation  of  a  low  enough  frequency  range  to  address  possible  amplification  of  the  emitted  signal  due  to  antenna  resonances  below  the  fundamental  emission. 

 254.  Comments/  Discussion.  There  were  no  pertinent  comments  regarding  the  proposed  frequency  range  over  which  measurements  should  be  performed.  Valeo  stated  that  the  measurement 
 ranges  are  appropriate  as  referenced  to  the  carrier  or  center  frequency.  381  Our  primary  concern  is  that  a  sufficient  frequency  range  be  investigated  to  ensure  that  the  emitted  signals  are  no  greater  than  the  limits 
 contained  in  Part  15  so  that  harmful  interference  is  not  caused  to  other  users  of  the  spectrum 
 255.  UWB  operation  is  unique  with  regard  to  the  possible  range  of  emissions  that  could  be  radiated  from  the  transmitter.  The  generated  pulse  could  result  in  a  fundamental  emission  that  is  several 

 gigahertz  wide.  Similarly,  the  side  lobes  also  could  be  several  gigahertz  wide  with  the  amplitude  of  the  secondary  lobe(  s)  only  attenuated  slightly  below  the  level  of  the  fundamental  emission.  It  is  the  resonant 
 frequency  of  the  antenna  employed  with  the  UWB  transmitter  that  determines  the  relative  amplitudes  of  the  radiated  emissions.  382  The  antenna  can  be  resonant  on  several  frequencies  over  a  wide  range  both  low 
 and  high.  Thus,  it  is  difficult  to  precisely  state  a  frequency  range  of  measurement. 
 256.  We  would  rather  proceed  cautiously  for  these  initial  standards.  We  believe  that  the  frequency  range  over  which  radiated  emissions  are  investigated  should  include  at  least  the  fundamental 

 emission  and  the  secondary  lobe  regardless  of  the  center  frequency.  This  can  be  accomplished  by  requiring  that  the  emissions  be  measured  up  to  at  least  the  center  frequency  added  to  three  divided  by  the 
 width  of  the  pulse  in  seconds.  Of  course,  we  recognize  that  there  is  no  need  to  require  the  emissions  to  be  measured  beyond  200  GHz,  as  could  otherwise  be  required  for  extremely  short  pulses.  383  On  the  other 
 hand,  we  do  not  wish  to  overburden  equipment  manufacturers  with  extensive  measurement  ranges  that  may  not  be  necessary.  Accordingly,  we  believe  that  we  can  compromise  by  establishing  the  following 
 parameters.  The  radio  spectrum  produced  by  a  UWB  transmitter  shall  be  investigated  from  the  lowest  frequency  generated  within  the  device,  without  going  below  9  kHz,  up  to  the  frequency  range  shown  in 
 47  C.  F.  R.    15.33(  a)  or  to  the  center  frequency  added  to  three  divided  by  the  pulse  width  in  seconds,  whichever  is  higher.  The  frequency  range  in  47  C.  F.  R.    15.33(  a)  shall  be  based  on  the  center  frequency 
 unless  a  higher  frequency,  e.  g.,  a  carrier  frequency,  is  generated  within  the  UWB  device.  There  is  no  requirement  to  measure  emissions  beyond  40  GHz  provided  the  center  frequency  is  less  than  10  GHz; 
 beyond  100  GHz  if  the  center  frequency  is  at  or  above  10  GHz  and  below  30  GHz;  or  beyond  200  GHz  if  the  center  frequency  is  at  or  above  30  GHz.  384 

 H.  Prohibition  Against  Class  B,  Damped  Wave  Emissions 
 257.  The  rules  prohibit  the  use  of  Class  B,  damped  wave  emissions.  385  This  prohibition  stems  from  a  similar  International  Telecommunication  Union  regulation  and  is  a  throwback  to  the  days  when 

 381  Valeo  comments  at  pg.  13. 
 382  Pulse  shaping  also  could  affect  the  characteristics  and  levels  of  the  radiated  emissions. 
 383  With  the  exception  of  radar  transmitters  operating  between  76-  77  GHz,  200  GHz  is  the  current  upper  range 
 of  measurements  for  Part  15  transmitters.  See  47  C.  F.  R.    15.  33(  a).  384 
 At  this  time,  we  are  not  adopting  regulations  that  would  permit  UWB  systems  to  operate  with  a  center  frequency  greater  than  30  MHz.  However,  we  see  no  reason  not  to  adopt  a  general  standard  for  the  frequency  range 

 of  measurement.  385 
 See  47  C.  F.  R.    2.201(  f)  and  15.5(  d). 
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 spark  gap  transmitters  were  employed.  386  There  is  no  longer  a  clear  definition  of  a  Class  B,  damped  wave  emission.  387  The  Commission  proposed  to  eliminate  the  prohibition  against  Class  B,  damped  wave 
 emissions  indicating  that  this  prohibition  does  not  appear  to  be  relevant  at  the  power  levels  being  proposed  for  UWB  transmissions.  These  levels  appear  to  be  low  enough  to  prevent  harmful  interference 
 to  other  users  of  the  spectrum.  Further,  unlike  conventional  damped  wave  transmissions  it  is  likely  that  the  receivers  associated  with  UWB  transmitters  would  attempt  to  recover  as  much  of  the  transmitted 
 bandwidth  as  possible  for  information  processing  purposes. 
 258.  Comments.  Few  comments  were  filed  in  response  to  this  proposal.  TDC  agreed  with  our  proposal  stating  that  the  prohibition  against  damped  wave  emissions  does  not  appear  relevant  to  the 

 current  UWB  technologies.  388  On  the  other  hand,  USGPSIC  objected  to  removing  the  prohibition  against  employing  damped  wave  emissions  stating  that  there  is  no  assurance  that  all  future  UWB  applications 
 will  employ  low  power  levels.  389  USGPSIC  stated  that  it  is  prudent  to  retain  the  prohibition  until  a  regulatory  environment  can  be  established  that  ensures  stability  of  the  national  information  infrastructure. 

 259.  Discussion.  The  objection  from  USGPSIC  has  no  technical  basis.  The  regulations  being  adopted  address  the  emission  limits  from  UWB  devices,  ensuring  that  these  devices  will  not  operate  at 
 power  levels  that  could  cause  harmful  interference  to  the  authorized  radio  services.  Accordingly,  our  original  supposition  has  been  satisfied,  and  we  are  eliminating  the  prohibition  against  damped  wave 
 operation  for  UWB  devices. 
 I.  Other  Matters 
 1.  Operation  of  Wide  Bandwidth  Systems  under  the  Existing  Rules 
 260.  Proposal.  In  the  Notice,  we  proposed  specific  regulations  regarding  the  frequency  of  operation  and  emission  levels  that  would  apply  to  UWB  devices.  We  expressed  concern  that  UWB 

 manufacturers  would  wish  to  operate  their  products  under  a  combination  of  both  the  UWB  regulations  and  the  existing  Part  15  regulations  in  47  C.  F.  R.    15.  217-  15.255.  This  would  result  in  a  transmitter  that 
 has  an  extremely  wide  bandwidth  attempting  also  to  operate  under  standards  that  were  developed  for  narrowband  operation.  An  example  would  be  a  UWB  device  that  operates  at  5800  MHz  attempting  to 
 demonstrate  compliance  with  47  C.  F.  R.    15.245  over  the  frequency  range  5785-  5815  MHz  while  demonstrating  compliance  with  the  UWB  emission  limits  outside  of  that  frequency  band.  To  prevent  this 
 method  of  cross-  rule  operation,  the  Commission  proposed  to  amend  47  C.  F.  R.    15.215(  c)  to  state  that  intentional  radiators  operated  under  the  provisions  of  47  C.  F.  R.    15.217-  15.  255  or  Subpart  E  of  the 
 current  regulations  must  be  designed  to  ensure  that  the  main  lobe  or  the  necessary  bandwidth,  whichever  is  less,  is  contained  within  the  frequency  bands  designated  in  those  rule  section  under  which  the 
 equipment  is  operated.  The  requirement  to  contain  the  fundamental  emission  within  one  of  the  specified  frequency  bands  would  include  the  effects  from  frequency  sweeping,  frequency  hopping  and  other 
 modulation  techniques  that  may  be  employed  as  well  as  the  frequency  stability  of  the  transmission  over 

 386  See  Chapter  II,  Article  5,  Section  8  of  the  Radio  Regulations  of  the  International  Telecommunication 
 Union.  387 
 The  term  damped  waves  (Type  B)  was  last  defined  in  Article  5,  Section  1  of  the  1938  version  of  the  ITU  regulations  as  [  w]  aves  composed  of  successive  series  of  oscillations  the  amplitude  of  which,  after  obtaining  a 

 maximum,  decreases  gradually,  the  wave  trains  being  keyed  according  to  a  telegraph  code.  A  more  modern  version  of  the  term  damped  wave  is  defined  in  the  IEEE  Standard  Dictionary  of  Electrical  and  Electronic  Terms,  IEEE  Std 
 100-  1972,  as  [  a]  wave  in  which,  at  every  point,  the  amplitude  of  each  sinusoidal  component  is  a  decreasing  function  of  time. 
 388  TDC  comments  at  pg.  44. 
 389  USGPSIC  comments  at  pg.  47-  48. 
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 variations  in  temperature  and  supply  voltage.  If  a  frequency  stability  were  not  specified,  the  regulation  would  continue  to  recommend  that  the  fundamental  emission  be  kept  within  at  least  the  central  80  percent 
 of  the  band  in  order  to  minimize  the  possibility  of  out-  of-  band  operation. 
 261.  Comments.  Interlogix  expressed  concern  on  how  to  compute  the  necessary  bandwidth  and  measurements  of  the  fundamental  lobe.  390  It  requested  that  the  determination  of  whether  an  emission 

 was  contained  within  one  of  the  frequency  bands  specified  in  47  C.  F.  R.    15.217-  15.255  should  be  based  on  the  20  dB  bandwidth  of  the  emission.  Bosch  requested  that  higher  emission  levels  be  permitted  for 
 UWB  devices  if  the  emission  is  located  in  one  of  the  ISM  bands.  391  TDC  requested  that  we  not  prohibit  dual  mode  devices  provided  each  mode  of  operation  qualifies  separately  under  the  pertinent 
 regulations.  392  Valeo  and  SARA  also  requested  the  ability  for  dual  mode  operation.  393  In  addition,  Delphi  and  SARA  requested  that  higher  UWB  emissions  be  permitted  if  the  emissions  are  located  in  the  ISM 
 bands.  394 
 262.  Discussion.  We  agree  with  Interlogix  that  the  20  dB  bandwidth  of  an  emission  is  an  appropriate  method  of  determining  if  an  emission  is  operating  within  one  of  the  frequency  bands  specified 

 in  47  C.  F.  R.    15.217-  15.  255  and  are  adopting  this  suggestion.  395  We  also  agree  that  dual  mode  operation  is  not  prohibited  provided  each  mode  of  operation  can  be  distinguished  and  demonstrated  to 
 comply  separately  under  the  pertinent  regulations.  396  However,  we  see  no  basis  for  permitting  emissions  from  UWB  devices  to  exceed  the  standards  being  adopted  in  this  proceeding  simply  because  the 
 emissions  happen  to  appear  in  an  ISM  band.  There  are  a  significant  number  of  other  radio  services  and  devices  operating  within  the  ISM  bands,  some  of  which  are  allocated  spectrum  for  this  purpose. 
 Examples  include  Location  Monitoring  Service  systems  in  the  915  MHz  band,  Amateur  Radio  Service  and  land  mobile  systems  operating  in  the  2450  MHz  band,  and  police  radar  systems  operating  in  the 
 24.125  GHz  band.  These  are  authorized  radio  services  and  are  protected  against  harmful  interference  from  the  operation  of  Part  15  devices,  regardless  of  whether  they  are  located  within  ISM  bands.  The 
 commenting  parties  have  not  provided  information  demonstrating  that  their  products  could  operate  without  causing  harmful  interference  to  these  authorized  services.  Even  so,  we  are  not  persuaded  that 
 higher  emission  limits  for  UWB  operation  are  prudent  at  this  time.  Once  we  have  gained  additional  experience  with  the  operation  of  UWB  devices  and  their  interference  potential,  additional  changes  to  the 
 rules  could  be  considered. 
 2.  Transition  Provisions 
 263.  In  the  Notice,  we  proposed  that  the  regulations  being  adopted  in  this  Report  and  Order  become  effective  60  days  from  its  date  of  publication  in  the  Federal  Register.  USGPS  objected  to  our 

 390  Interlogix  comments  at  pg.  4-  5  and  reply  comments  at  pg.  2.  We  note  that  Interlogix  redesigned  its 
 equipment  in  order  to  be  certified  under  the  provisions  of  47  C.  F.  R.    15.  249.  391 
 Bosch  comments  at  pg.  5  and  reply  comments  at  pg.  5.  392 
 TDC  comments  at  pg.  44-  45.  393 
 Valeo  comments  at  pg.  4;  SARA  ex  parte  filing  of  11/  14/  01.  394 
 Delphi  comments  at  pg.  17-  18;  SARA  ex  parte  filing  of  11/  14/  01.  The  ISM  bands  refer  to  the  frequency  bands  under  47  C.  F.  R.    18.  301,  e.  g.,  the  bands  on  which  operation  is  permitted  under  47  C.  F.  R.    15.  245-  15.249. 

 395  Any  emissions  appearing  outside  of  the  specified  frequency  band  must  continue  to  meet  the  emission  limits 
 even  if  those  limits  require  an  attenuation  of  greater  than  20  dB.  For  example,  a  spread  spectrum  system  operating  at  2400-  2483.  5  MHz  under  47  C.  F.  R.    15.245  must  attenuate  emissions  in  the  2483.  5-  2500  MHz  band  by 

 significantly  greater  than  20  dB.  We  are  using  the  20  dB  bandwidth  only  to  determine  that  the  emission  is  contained  within  the  specified  band. 
 396  We  do  not  believe  that  a  specific  regulation  is  required  for  this  interpretation. 
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 proposal,  stating  that  it  is  premature  to  permit  the  regulations  to  become  effective  within  60  days  of  publication  in  the  Federal  Register.  397  USGPSIC  added  that  additional  proposals  are  needed,  and  that 
 these  would  be  major  rule  changes  requiring  congressional  review. 
 264.  We  recognize  that  this  proceeding  is  considered  to  be  a  major  action  and  that  the  effective  date  is  delayed  for  60  days  under  the  Contract  with  America  Advancement  Act  of  1996.  398  This 

 provides  Congress  with  sufficient  time  to  review  our  decisions,  if  it  so  desires.  Absent  adoption  of  a  petition  for  stay  or  a  court-  order  stay  of  this  proceeding,  we  see  no  justification  for  delaying  further  the 
 effective  date. 
 3.  Existing  Waivers 
 265.  The  Commission  has  issued  four  waivers  to  permit  the  manufacture  of  UWB  devices.  Three  of  the  waivers  were  issued  on  June  25,  1999.  TDC  was  issued  a  waiver  for  UWB  systems  that 

 would  be  used  by  public  safety  personnel  for  high  resolution  imaging  of  persons  and  objects  behind  walls  or  under  debris.  Zircon  was  issued  a  waiver  for  UWB  radar  systems  that  would  be  used  by  the 
 construction  industry  to  detect  objects  hidden  inside  walls  or  other  building  materials.  U.  S.  Radar  was  issued  a  waiver  for  ground  penetrating  radar  systems.  A  fourth  waiver  was  issued  on  August  6,  2001,  to 
 Kohler  Co.  to  permit  it  to  market  UWB  toilet  ventilating  devices.  These  waivers  were  scheduled  to  terminate  upon  the  effective  date  of  the  Report  and  Order  in  this  proceeding. 

 266.  On  August  16,  2001,  Kohler  filed  a  request  to  permit  it  to  continue  to  market  its  product  under  the  waiver  until  one  year  from  the  effective  date  of  this  Report  and  Order.  Kohler,  noting  that  the 
 adopted  rules  may  be  different  than  those  under  which  the  waiver  was  granted,  cited  the  time  necessary  to  redesign  its  product,  to  test  the  redesigned  device  and  to  modify  its  tooling.  We  sympathize  with 
 Kohlers  concerns  and  believe  that  these  problems  also  would  affect  other  companies  marketing  equipment  under  a  waiver.  Accordingly,  we  are  extending  the  cut-  off  dates  of  the  waivers  issued  to  Time 
 Domain  Corp.,  to  U.  S.  Radar,  to  Zircon,  and  to  Kohler  for  a  period  of  one  year  from  the  effective  date  of  this  Report  and  Order. 

 4.  Miscellaneous  Issues 
 267.  Further  Notice  of  Proposed  Rule  Making.  A  number  of  parties  requested  that  the  Commission  issue  a  further  notice  of  proposed  rule  making  before  adopting  final  rules.  399  They  argue, 

 generally,  that  the  Notice  was  inadequate  because  it  did  not  include  the  text  of  the  proposed  rules.  They  also  claim  that  the  Commission  must  update  the  proposals  to  take  into  account  the  information  contained 
 in  the  various  test  reports  filed  in  the  record.  As  stated  by  ARRL,  the  Notice  included  no  proposed  rules,  listed  a  few  generalized  tentative  conclusions  about  UWB,  and  was  more  akin  to  a  Notice  of  Inquiry.  400 
 Contrary  to  these  comments,  Fantasma  and  XSI  asserted  that  each  regulatory  measure  was  contemplated  in  the  Notice  and  can  be  implemented  without  a  further  notice  of  proposed  rule  making.  401 

 268.  It  is  true  that  the  Notice  did  not  include  the  precise  language  of  the  rules  we  are  adopting  today.  However,  the  Commission  did  provide  a  general  picture  of  what  it  intended  to  do  and  that  is 

 397  USGPSIC  comments  at  pg.  48-  52. 
 398  See  5  U.  S.  C.    801  et  seq. 
 399  See,  for  example,  ATA  et  al  late  filed  comments  of  3/  27/  01,  and  MSSI  late  filed  comments  of  10/  9/  01. 
 MSSI  rescinded  its  request  in  an  ex  parte  filing  of  11/  12/  01.  400 
 ARRL  comments  at  pg.  3.  401 
 Fantasma  late  filed  comments  of  4/  2/  01;  XSI  late  comments  of  4/  12/  01  and  ex  parte  filing  of  7/  25/  01. 
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 legally  adequate  under  the  Administrative  Procedure  Act.  402  In  California  Citizens  Band  Association  v.  U.  S.,  375  F  2d  43,  48-  49  (9  th  Cir.  1967),  cert.  denied,  389  U.  S.  844  (1967),  the  court  held  that  the 
 Administrative  Procedure  Act  ...  does  not  require  an  agency  to  publish  in  advance  every  precise  proposal  which  it  may  ultimately  adopt  as  a  rule.  ...[  A]  notice  of  rulemaking  is  sufficient  if  it  provides  a 
 description  of  the  subjects  and  issues  involved.  Similarly,  the  court  in  Forester  v.  Consumer  Product  Safety  Comn,  559  F  2d  774,  787  (D.  C.  Cir.  1977)  held  that  Section  553(  b)  does  not  require  that 
 interested  parties  be  provided  precise  notice  of  each  aspect  of  the  regulations  eventually  adopted.  Rather,  notice  is  sufficient  if  it  affords  interested  parties  a  reasonable  opportunity  to  participate  in  the  rulemaking 
 process...  Additional  legal  citations  were  provided  by  Fantasma  in  its  filing  of  April  2,  2001,  and  by  XSI  in  its  filing  of  April  12,  2001. 

 269.  Several  hundred  comments  have  been  filed  in  this  proceeding,  including  comments  on  the  various  technical  reports  and  analyses.  It  is  clear  from  this  record  that  the  commenters  well 
 understood  the  regulations  under  consideration  for  amendment  and  the  scope  of  proposed  changes  under  consideration.  We  find  that  there  is  sufficient  information  in  the  record  to  make  initial  decisions  at  this 
 time  that  provide  for  the  introduction  of  UWB  technology  based  on  standards  that  are  extremely  conservative  in  protecting  radio  services  against  harmful  interference.  We  recognize,  however,  that  as 
 this  technology  develops  and  we  gain  experience  with  the  potential  interference  of  UWB  devices,  it  is  appropriate  to  reexamine  these  rules.  Accordingly,  within  the  next  six  to  twelve  months  we  intend  to 
 review  the  standards  for  UWB  devices  and  issue  a  further  rule  making  to  explore  more  flexible  technical  standards  and  to  address  the  operation  of  additional  types  of  UWB  operations  and  technology.  In  the 
 meantime,  we  plan  to  expedite  enforcement  action  for  any  UWB  products  found  to  be  in  violation  of  the  rules  we  are  adopting  and  will  act  promptly  to  eliminate  any  reported  harmful  interference  from  UWB 
 devices. 
 270.  Delphi  and  Other  Automotive  Radar  Systems.  Delphi  requested  that  we  include  its  radar  system  operating  at  24.125  GHz  under  our  provisions  for  UWB  operation.  403  Delphi  indicated  that  it 

 operates  at  17  GHz  and  at  24.125  GHz  and  uses  several  different  modulation  types,  including  swept  frequency  modulation.  However,  it  is  the  24.125  GHz  system  operating  with  a  pseudo-  noise  direct 
 sequence  binary  phase  shift  key  waveform  that  Delphi  requested  for  inclusion.  This  system  transmits  in  the  restricted  band  below  24  GHz  at  the  limit  in  47  C.  F.  R.    15.209.  SARA  also  has  expressed  interest  in 
 a  similar  technology.  404  We  find  that  the  SARA  and  Delphi  systems,  excluding  the  swept  frequency  modulated  system,  fall  under  the  definition  being  adopted  in  this  proceeding  and  that  no  further  action  is 
 necessary. 
 5.  Other  Matters 
 271.  Operation  in  the  PCS  Bands.  Sprint  objected  to  the  basic  concept  of  UWB  operation,  stating  that  the  Commission  does  not  have  a  legal  right  to  convert  Sprints  licenses  into  non-  exclusive 

 licenses  and  to  require  Sprint  PCS  to  share  its  spectrum  with  others,  much  less  share  it  for  free.  405  Sprint  PCS  added  that  it  spent  over  $3  billion  for  exclusive  PCS  licenses  and  that  Commission  authorization  of 
 new  users  constitutes  breach  of  contract  and  an  unlawful  modification  of  licenses  for  which  the 
 402  See  5  U.  S.  C.  553. 
 403  See  Delphi  comments,  reply  comments  and  ex  parte  filings  of  4/  24/  01,  6/  07/  01,  7/  13/  01,  and  9/  20/  01. 
 404  SARA  ex  parte  filing  of  11/  14/  01.  SARA  also  expressed  concern  regarding  the  residual  carrier  emission 
 produced  by  its  homodyne  receiver.  This  issue  will  be  addressed  upon  such  time  as  the  equipment  is  submitted  for  authorization  under  our  certification  procedure.  However,  we  note  that  the  levels  of  radiated  emissions  due  to  the 

 local  oscillator  of  a  receiver  operating  above  960  MHz  is  not  addressed  under  Part  15,  other  than  the  requirement  that  the  emissions  not  cause  harmful  interference  to  other  radio  operations.  See  47  C.  F.  R.    15.  101(  b). 
 405  Sprint  reply  comments  at  pg.  13-  14  and  comments  of  4/  25/  01  at  pg.  8. 
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 Government  would  be  liable  for  damages.  406  However,  no  such  contractual  exclusivity  exists.  This  spectrum  is  not,  and  has  never  been,  exclusive  to  Sprint  or  to  any  other  licensee  or  user.  While  Sprint 
 PCS  has  been  provided  some  exclusivity  in  operating  licensed  PCS  systems  within  specified  geographic  areas,  Part  15  transmitters  currently  are  permitted  to  operate  within  the  PCS  and  cellular  frequency  bands 
 at  considerably  higher  emission  levels  than  those  being  adopted  in  this  Report  and  Order.  407  In  addition,  there  are  countless  other  devices  that  emit  radio  emissions  within  these  bands.  In  any  event,  we  have  not 
 in  this  proceeding  permitted  any  UWB  devices  to  deliberately  emit  in  the  PCS  bands.  Much  as  we  have  done  for  other  RF  devices,  we  have  simply  established  limits  on  out-  of-  band  and  spurious  emissions  from 
 UWB  devices  that  are  designed  to  reduce  the  probability  that  harmful  interference  would  be  caused. 
 272.  Exemption  of  Unlicensed  PCS  Transmitters  from  the  Restricted  Bands.  Under  the  current  rules,  unlicensed  PCS  transmitters  operating  under  Subpart  D  of  Part  15  are  not  subject  to  the  restricted 

 band  provisions  in  47  C.  F.  R.    15.205.  The  cross-  reference  in  Subpart  D  to  other  applicable  Part  15  regulations,  as  specified  in  47  C.  F.  R.    15.309,  does  not  include  Subpart  C  of  Part  15  or  any  of  the 
 individual  regulations  contained  in  that  subpart.  Thus,  47  C.  F.  R.    15.  205,  which  is  contained  in  Subpart  C,  does  not  apply  to  unlicensed  PCS  transmitters.  408  We  are  taking  the  opportunity  provided  by  this 
 Report  and  Order  to  clarify  this  current  standard  in  our  amendment  to  47  C.  F.  R.    15.205.  As  this  amendment  to  the  rules  only  clarifies  an  existing  regulation,  prior  notice  and  comment  are  unnecessary.  409 

 273.  U.  S.  Government  Operation  of  UWB  Devices.  When  the  Part  15  regulations  were  amended  in  1989,  410  the  Commission  opened  several  frequency  bands  for  unlicensed  operation  even  though  those 
 bands  were  allocated  for  exclusive  operation  by  the  U.  S.  Government.  The  Commission  took  this  action  following  an  informal  agreement  with  NTIA  that  similarly  permitted  it  to  operate  equipment  in  exclusive 
 non-  government  bands  under  the  same  Part  15  standards.  411  We  will  continue  this  policy,  permitting  the  U.  S.  Government  to  operate  in  non-  government  frequency  bands  and  in  shared  frequency  bands  under  the 
 Part  15  standards.  Accordingly,  as  a  condition  of  their  use  of  these  bands  U.  S.  Government  specifications  for  UWB  devices  operated  by  the  U.  S.  Government  agencies  in  non-  government  or  in  shared  frequency 
 bands  must  conform  to  the  standards  and  operating  conditions  that  are  being  adopted  in  this  Order.  412  We  believe  that  this  will  result  in  a  greater  number  of  UWB  devices  operating  under  the  same  parameters, 
 facilitating  our  studies  to  readdress  the  appropriateness  of  the  UWB  standards  within  the  next  six  to  12  months. 

 V.  PROCEDURAL  MATTERS 
 274.  Paperwork  Reduction  Act  of  1995  Analysis.  This  Report  &  Order  contains  modified  information  collection  subject  to  the  Paperwork  Reduction  Act  of  1995  (PRA),  Public  Law  104-  13.  It 

 will  be  submitted  to  the  Office  of  Management  and  Budget  (OMB)  for  review  under  Section  3507(  d)  of  the  PRA.  OMB,  the  general  public,  and  other  Federal  agencies  are  invited  to  comment  on  the  modified 

 406  Sprint  PCS  comments  of  4/  6/  01  at  pg.  2. 
 407  See  47  C.  F.  R.    15.  231. 
 408  Unlicensed  PCS  transmitters  operate  in  the  bands  1910-  1930  MHz  and  2390-  2400  MHz.  The  exemption 
 from  the  restricted  bands  only  affects  the  limits  for  some  of  the  unwanted  emissions.  The  unwanted  emissions  are  required  to  comply  with  the  limits  in  47  C.  F.  R.    15.  321(  d)  and  15.  323(  d),  as  appropriate. 

 409  See  47  U.  S.  C.  553(  b)(  B). 
 410  See  First  Report  and  Order  in  GEN  Docket  No.  87-  389,  4  FCC  Rcd.  3493  (1989). 
 411  See  Manual  of  Regulations  and  Procedures  for  Federal  Radio  Frequency  Management,  U.  S.  Department 
 of  Commerce,  National  Telecommunications  and  Information  Administration,  January  2000,  at  Sections  7.8  and  7.  9.  412 
 The  operation  in  non-  government  bands  of  UWB  devices  that  are  not  in  compliance  with  the  technical  and  administrative  provisions  contained  in  this  Order  is  not  permitted  without  the  concurrence  of  the  FCC. 
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 information  collection  contained  in  this  proceeding. 
 275.  Final  Regulatory  Flexibility  Certification.  The  Regulatory  Flexibility  Act  of  1980,  as  amended  (RFA)  413  requires  that  a  regulatory  flexibility  analysis  be  prepared  for  rulemaking  proceedings, 

 unless  the  agency  certifies  that  "the  rule  will  not  have  a  significant  economic  impact  on  a  substantial  number  of  small  entities."  414  The  RFA  generally  defines  "small  entity"  as  having  the  same  meaning  as  the 
 terms  "small  business,"  "small  organization,"  and  "small  governmental  jurisdiction."  415  In  addition,  the  term  "small  business"  has  the  same  meaning  as  the  term  "small  business  concern"  under  the  Small 
 Business  Act.  416  A  small  business  concern  is  one  which:  (1)  is  independently  owned  and  operated;  (2)  is  not  dominant  in  its  field  of  operation;  and  (3)  satisfies  any  additional  criteria  established  by  the  Small 
 Business  Administration  (SBA).  417 
 276.  In  this  First  Report  and  Order,  we  are  amending  Part  15  of  our  rules  to  permit  the  marketing  and  operation  of  new  products  incorporating  ultra-  wideband  ("  UWB")  technology.  UWB 

 devices  operate  by  employing  very  narrow  or  short  duration  pulses  that  result  in  very  large  or  wideband  transmission  bandwidths.  UWB  devices  have  the  capability  to  provide  for  significant  benefits  for  public 
 safety,  businesses  and  consumers.  With  appropriate  technical  standards,  UWB  devices  can  operate  on  spectrum  occupied  by  existing  radio  services  without  causing  interference,  thereby  permitting  scarce 
 spectrum  resources  to  be  used  more  efficiently. 
 277.  We  note  that  the  Aircraft  Owners  and  Pilots  Association  (AOPA)  along  with  the  National  Business  Aviation  Association  (NBAA)  commented  that  the  impact  on  small  entities  could  not  be 

 estimated  at  this  time.  418  They  added  that  their  constituency  substantially  consists  of  small  entities,  comprising  individuals  and  small  businesses  that  are  aircraft  owners  and  operators.  AOPA  and  NBAA 
 expressed  concern  that  there  would  be  a  severe  and  lengthy  impact  to  aeronautical  operations  should  the  UWB  standards  prove  to  be  inadequate  to  protect  aeronautical  communications,  navigation  and 
 surveillance  functions.  However,  as  demonstrated  in  our  analyses  of  the  interference  studies  on  GPS  there  should  be  no  impact  to  aeronautical  radio  operations  from  UWB  devices  operating  under  the 
 technical  limits  and  operational  requirements  we  are  adopting.  Therefore,  we  find  that  our  action  will  have  no  negative  impact  on  this  industry  and  in  fact  will  have  a  positive  impact.  Further,  as  noted  in  the 
 text  we  currently  are  limiting  the  expansion  of  UWB,  out  of  an  abundance  of  caution,  until  such  time  as  we  gain  additional  experience.  Thus,  we  expect  that  our  actions  do  not  amount  to  a  significant  economic 
 impact  at  this  time.  Accordingly,  we  certify  that  the  rules  being  adopted  in  this  Report  and  Order  will  not  have  a  significant  economic  impact  on  a  substantial  number  of  small  entities. 

 413  The  RFA,  see    5  U.  S.  C.  S  601  et.  seq.,  has  been  amended  by  the  Contract  With  America  Advancement 
 Act  of  1996,  Pub.  L.  No.  104-  121,  110  Stat.  847  (1996)  (CWAAA).  Title  II  of  the  CWAAA  is  the  Small  Business  Regulatory  Enforcement  Fairness  Act  of  1996  (SBREFA). 

 414  5  U.  S.  C.    605(  b). 
 415  5  U.  S.  C.    601(  6). 

 416  5  U.  S.  C.    601(  3)  (incorporating  by  reference  the  definition  of  "small  business  concern"  in  Small 
 Business  Act,  15  U.  S.  C.  S    632).  Pursuant  to  5  U.  S.  C.    601(  3),  the  statutory  definition  of  a  small  business  applies  "unless  an  agency,  after  consultation  with  the  Office  of  Advocacy  of  the  Small  Business 

 Administration  and  after  opportunity  for  public  comment,  establishes  one  or  more  definitions  of  such  term  which  are  appropriate  to  the  activities  of  the  agency  and  publishes  such  definition(  s)  in  the  Federal 
 Register." 
 417  Small  Business  Act,    15  U.  S.  C.  S  632.  418 
 AOPA  comments  at  pg.  16-  17;  NBAA  comments  at  pg.  17. 
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 278.  We  will  send  a  copy  of  the  First  Report  and  Order,  including  a  copy  of  this  final  certification,  in  a  report  to  Congress  pursuant  to  the  Congressional  Review  Act.  419  In  addition,  the  First 
 Report  and  Order  and  this  certification  will  be  sent  to  the  Chief  Counsel  for  Advocacy  of  the  Small  Business  Administration,  and  will  be  published  in  the  Federal  Register.  420 

 VI.  ORDERING  CLAUSES 
 279.  IT  IS  ORDERED  that  Part  15  of  the  Commissions  Rules  and  Regulations  IS  AMENDED  as  specified  in  Appendix  D,  effective  60  days  after  publication  in  the  Federal  Register.  This 

 action  is  taken  pursuant  to  Sections  4(  i),  302,  303(  e),  303(  f),  303(  r),  304  and  307  of  the  Communications  Act  of  1934,  as  amended,  47  U.  S.  C.  Sections  154(  i),  302,  303(  e),  303(  f),  303(  r),  304  and  307. 

 280.  IT  IS  FURTHER  ORDERED  that  the  waivers  issued  on  June  25,  1999,  to  Time  Domain  Corporation,  to  U.  S.  Radar  Inc.,  and  to  Zircon  Corp.  and  the  waiver  issued  on  August  6,  2001,  to  Kohler 
 Co.  to  permit  the  manufacture  and  marketing  of  their  UWB  devices  remain  in  effect  until  one  year  from  the  effective  date  of  this  Report  and  Order. 

 281.  IT  IS  FURTHER  ORDERED  that  the  Commissions  Consumer  and  Governmental  Affairs  Bureau,  Reference  Information  Center,  SHALL  SEND  a  copy  of  this  Report  and  Order,  including 
 the  Final  Regulatory  Flexibility  Analysis,  to  the  Chief  Counsel  for  Advocacy  of  the  Small  Business  Administration. 

 282.  For  further  information  regarding  this  Report  and  Order,  contact  John  A.  Reed,  Office  of  Engineering  and  Technology,  (202)  418-  2455,  jreed@  fcc.  gov. 

 FEDERAL  COMMUNICATIONS  COMMISSION 

 Marlene  H.  Dortch  Secretary 

 419  See  5  U.  S.  C.    801(  a)(  1)(  A) 
 420  See  5  U.  S.  C.    605(  b). 
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 APPENDIX  A  Commenting  Parties 
 Parties  filing  comments: 
 1.  Aeronautical  Radio,  Inc.  &  the  Air  Transport  Association  of  America,  Inc.  2.  Aether  Wire  &  Location,  Inc. 
 3.  Aircraft  Owners  and  Pilots  Association  4.  Alzheimers  Association,  Coastal  Carolina  Chapter 
 5.  Alzheimers  Association,  Middle  Mississippi  Chapter  6.  The  Amyotropic  Lateral  Sclerosis  Association,  Keith  Worthington  Chapter 
 7.  The  Amyotropic  Lateral  Sclerosis  Association,  Western  Ohio  Chapter  8.  A.  Peter  Annan 
 9.  ANRO  Engineering,  Inc.  10.  Senator  Bill  Armistead,  Alabama  State  Senate 
 11.  Arc  of  Tennessee  12.  ARRL,  The  National  Association  for  Amateur  Radio 
 13.  Arthur  D.  Little,  Inc.  14.  The  Associated  General  Contractors  of  America 
 15.  Assistance  of  Independent  Living,  Inc.  16.  Astatula  Police  Department  (Florida) 
 17.  AT&  T  Wireless  Services,  Inc.  18.  Ball  &  Associates 
 19.  Berwyn  Fire  Department  (Illinois)  20.  A/  Prof.  Marek  Bailkowski,  University  of  Queensland 
 21.  Boeing  Company  22.  Burbank  Fire  Department 
 23.  Centre  for  Sensor  Signal  and  Information  Processing  24.  Cisco  Systems,  Inc. 
 25.  Colingo,  Williams,  Heidelberg,  Steinberger  &  McElhaney,  P.  A.  (2)  26.  Comprehensive  Cancer  Institute 
 27.  Thomas  J.  Cooper  28.  Congressman  Bud  Cramer,  et  al. 
 29.  Daniel  Group  30.  Decatur  Police  Department,  Criminal  Investigation  Division  (Alabama) 
 31.  Delphi  Automotive  Systems  Corporation  32.  Deutsche  Bank  Securities  Inc. 
 33.  William  E.  N.  Doty  34.  Dulac  Fire  Protection  District  4-  A  (Louisiana) 
 35.  DVP  Incorporated  36.  Endress  +  Hauser  GmbH  &  Co. 
 37.  Envoy  Corporation  38.  Fairlawn  Fire  Department  (Ohio) 
 39.  Fantasma  Networks,  Inc.  40.  Farmington  Department  of  Public  Safety  (Michigan) 
 41.  Federal  Law  Enforcement  Wireless  Users  Group  42.  Federal  Republic  of  Germany,  Liaison  Office  for  Defense  Materiel  USA/  Canada 
 43.  Florida  Adult  Day  Care  Association  44.  Gordon  E.  Fornell 
 45.  Charles  Alton  Forsberg  46.  Fraternal  Order  of  Police 
 47.  Frontier  Capital,  LLC  48.  Garmin  International,  Inc. 
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 49.  General  Electric  Company  50.  Globe  Fire  Department  (Arizona) 
 51.  Golf-  Domain  52.  Groveland  Police  Department  (Florida) 
 53.  The  Heart  Center,  P.  C.  54.  Helena  Fire  Department  (Montana) 
 55.  Hewlett-  Packard  Company  56.  Houma  Police  Department  (Louisiana) 
 57.  Houston  Police  Department  (Texas)  58.  Representative  Mike  Hubbard,  Alabama  House  of  Representatives 
 59.  Iberia  Parish  Council  on  Aging,  Inc.  (Louisiana)  60.  Intelligent  Automation,  Inc. 
 61.  Interlogix,  Inc.  62.  International  Association  of  Fire  Chiefs 
 63.  International  Brotherhood  of  Electrical  Workers  64.  Irmo  Fire  District  (South  Carolina) 
 65.  Jore  Corporation  66.  Joseph  Decosimo  and  Company 
 67.  Kohler  Co.  68.  Krohne  America  Inc. 
 69.  L-  3  Communications  70.  Laborers  International  Union  of  North  America 
 71.  Leesburg  Fire  Department  (Florida)  72.  Lockheed  Martin  Corporation 
 73.  Lockheed  Martin  Information  Systems  74.  Los  Angeles  County  Sheriffs  Department  (California) 
 75.  Senator  Trent  Lott  76.  Lucent  Technologies  Inc. 
 77.  M/  A-  COM  78.  Maricopa  County  Emergency  Management  (Arizona) 
 79.  McNeese  State  University  80.  Metricom,  Inc. 
 81.  Metro  Area  Agency  on  Aging  (W.  Virginia)  82.  Mobile  Communications  Holdings,  Inc. 
 83.  Moose  Hill  Enterprises,  Inc.  84.  Motorola,  Inc. 
 85.  Multispectral  Solutions,  Inc.  86.  National  Alliance  for  the  Mentally  Ill,  Illinois 
 87.  National  Alliance  for  the  Mentally  Ill,  Kansas  88.  National  Alliance  for  the  Mentally  Ill,  South  Dakota 
 89.  National  Association  of  Broadcasters  90.  National  Business  Aviation  Association,  Inc. 
 91.  National  Safe  Skies  Alliance  92.  National  Telecommunications  and  Information  Administration 
 93.  National  Thoroughbred  Racing  Association  94.  National  Volunteer  Fire  Council 
 95.  Noro-  Moseley  Partners  (2)  96.  Nortel  Networks  Inc. 
 97.  Ohio  Statewide  Independent  Living  Council  98.  OnScene,  Inc. 
 99.  Plymouth  Township  Police  Department  (Michigan)  100.  Professor  Jon  M.  Peha,  Carnegie  Mellon  University 
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 101.  Qualcomm  Incorporated  102.  Rainbow/  PUSH  Coalition 
 103.  Redwood  City  Fire  Department  (California)  104.  Richards  Lighting 
 105.  Roane  County  Committee  on  Aging,  Inc.  (W.  Virginia)  106.  Robert  Bosch  Gmbh 
 107.  Rockwell  Collins,  Inc.  108.  Saab  Marine  Electronics 
 109.  San  Mateo  County,  Office  of  the  Sheriff  (California)  110.  Satellite  Industry  Association 
 111.  James  J.  Schaffer  112.  Professor  Robert  Scholtz,  University  of  Southern  California 
 113.  Science  Applications  International  Corporation  114.  Senior  Citizens,  Inc. 
 115.  Senior  Companion  Program,  Van  Buren  Community  Development  and  Services  Board  (Tennessee) 
 116.  Senator  Jeff  Sessions,  U.  S.  Senate  117.  Siemens  Automotive 
 118.  Siemens  Corporation  119.  Sierra  Monolithics,  Incorporated 
 120.  Singing  River  Hospital  (Mississippi)  121.  Sioux  Falls  Fire  Rescue  (South  Dakota) 
 122.  SiRF  Technology,  Inc.  123.  Sirius  Satellite  Radio  Inc. 
 124.  Sony  Corporation  125.  South  Dakota  Coalition  of  Citizens  with  Disabilities 
 126.  Sprint  127.  Sprint  Corporation 
 128.  Staenberg  Private  Capital,  LLC  129.  Stanford  University,  Department  of  Aeronautics  and  Astronautics 
 130.  STEP  Inc.  131.  Stephens  Inc. 
 132.  Steven  T.  Suess  133.  Tacoma-  Pierce  County  Chamber  of  Commerce  (Washington) 
 134.  Tallahassee  Senior  Center  (Florida)  135.  Congressman  Billy  Tauzin,  et  al. 
 136.  Tennessee  Disability  Coalition  137.  Terrebonne  Parish  Sheriffs  Office  (Louisiana) 
 138.  Time  Domain  Corporation  139.  Peter  W.  Torode 
 140.  Tri-  City  Fire  District  (Arizona)  141.  UCI 
 142.  University  of  Mississippi,  Office  of  the  Chancellor  143.  Upper  East  Tennessee  Human  Development  Agency,  Inc. 
 144.  U.  S.  Department  of  Justice,  Federal  Bureau  of  Prisons  145.  U.  S.  Department  of  the  Navy,  Office  of  the  Assistant  Secretary 
 146.  U.  S.  Department  of  Transportation  147.  U.  S.  GPS  Industry  Council 
 148.  Valeo  Electronics  149.  Virginia  Task  Force  One 
 150.  Virtual  Education,  Inc.  151.  Wakefield  Police  Department  (Massachusetts) 
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 152.  Congressman  Curt  Weldon  153.  West  Virginia  Department  of  Health  and  Human  Resources 
 154.  Wheeling  Jesuit  University,  Office  of  Law  Enforcement  Technology  Commercialization  (West  Virginia) 
 155.  Lt.  Governor  Steve  Windom,  State  of  Alabama  156.  Wireless  Communications  Association  International,  Inc.  (  WCA) 
 157.  XM  Radio  Inc.  158.  XtremeSpectrum,  Inc. 
 159.  Zircon  Corporation 
 Parties  filing  reply  comments: 
 1.  Aeronautical  Radio,  Inc.  and  the  Air  Transport  Association  of  America,  Inc.  2.  Aerospace  Industries  Association 
 3.  Aerospace  States  Association  (ASA)  4.  Aircraft  Owners  and  Pilots  Association  (AOPA) 
 5.  Alliance  for  Telecommunications  Industry  Solutions  (ATIS)  6.  Alloy  LLC 
 7.  American  Association  of  People  with  Disabilities  8.  American  Telemedicine  Association 
 9.  American  Trans  Air,  Inc.  10.  Apple  Valley  Fire  Protection  District,  California 
 11.  ARRL,  The  National  Association  for  Amateur  Radio  12.  AT&  T  Wireless  Services,  Inc. 
 13.  Aviation  Management  Associates,  Inc.  (AMA)  14.  Clovis  Firefighters  Association 
 15.  Colorado  School  of  Mines,  Department  of  Geophysics  16.  Community  Technology  Centers  Network  (CTCNet) 
 17.  Computer  &  Communications  Industry  Association  (CCIA)  18.  Consortium  for  School  Networking  (CoSN) 
 19.  Consumers  Union  and  the  Consumer  Federation  of  America  20.  Council  of  Chief  State  School  Officers  (D.  C.) 
 21.  Daimler  Chrysler  Research  and  Technology  North  America  22.  Dain  Rauscher  Wessels 
 23.  Delphi  Automotive  Systems  Corporation  24.  Disability  Rights  Education  and  Defense  Fund,  Inc. 
 25.  Dr.  William  E.  English  26.  Fantasma  Networks,  Inc. 
 27.  Fraternal  Order  of  Police  (Albuquerque,  New  Mexico)  28.  Garmin  International,  Inc. 
 29.  Dr.  Jim  Grigsby  30.  Hays  Medical  Center  (Kansas) 
 31.  Iberia  Medical  Center  (Louisiana)  32.  Intel  Corporation 
 33.  Interagency  GPS  Executive  Board  (IGEB)  34.  Interlogix  Inc. 
 35.  IPEG  Corporation  36.  iTelehealth,  Inc. 
 37.  Kohler  Co.  38.  Krohne,  Inc. 
 39.  Lockheed  Martin  Corporation  (2)  40.  Lucent  Technologies  Inc. 
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 41.  M/  A-  COM  42.  Motorola,  Inc. 
 43.  Multispectral  Solutions,  Inc.  44.  National  Alliance  for  the  Mentally  Ill,  Tennessee 
 45.  National  Association  of  County  and  City  Health  Officials  46.  National  Business  Aviation  Association,  Inc. 
 47.  National  Catholic  Educational  Association  48.  National  Safe  Skies  Alliance 
 49.  National  Spectrum  Managers  Association  50.  NAV  Canada,  SatNav 
 51.  NovAtel  Inc.  52.  Robert  Bosch  Gmbh 
 53.  Rockwell  Collins,  Inc.  54.  Rural  Wisconsin  Health  Cooperative 
 55.  Rush  Advanced  Technology  &  International  Health  56.  Satellite  Industry  Association  (SIA) 
 57.  SBK  Capital,  LLC  58.  Nancy  J.  Sharp 
 59.  Don  Siegelman,  Governor,  State  of  Alabama  60.  SiRF  Technology,  Inc.  &  Trimble  Navigation  Limited 
 61.  Sirius  Satellite  Radio  Inc.  62.  Sprint 
 63.  Sprint  PCS  64.  STMicroelectronics  (ST) 
 65.  Stroud  Engineering  Services,  Inc.  66.  Time  Domain  Corporation  (2) 
 67.  United  States  Catholic  Conference  68.  U.  S.  Department  of  Defense 
 69.  U.  S.  Department  of  Transportation  70.  U.  S.  GPS  Industry  Council 
 71.  University  NAVSTAR  Consortium  72.  University  of  Arkansas  for  Medical  Sciences,  Rural  Hospital  Program 
 73.  Verizon  Telephone  Companies  74.  Dr.  John  Michael  Williams 
 75.  John  A.  Williamson,  Sr.  76.  Steve  Windom,  Lieutenant  Governor,  State  of  Alabama 
 77.  Worldcom,  Inc.  78.  XM  Radio  Inc. 
 79.  XtremeSpectrum,  Inc.  80.  Zircon  Corporation 
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 Appendix  B  Comments  in  Response  to  NTIAs  Study  of  Potential 
 Interference  to  non-  GPS  Systems 
 Parties  filing  comments: 
 1.  Aeronautical  Radio,  Inc.  and  the  Air  Transport  Association  of  America,  Inc.  (ARINC/  ATA)  2.  AT&  T  Wireless  Services,  Inc.  (AT&  T) 
 3.  Cingular  Wireless  LLC  (Cingular)  4.  Fantasma  Networks,  Inc.  (Fantasma) 
 5.  Federal  Law  Enforcement  Wireless  Users  Group  (FLEWUG)  6.  Nickolaus  E.  Leggett 
 7.  Lockheed  Martin  Corporation  (LMC)  8.  Multispectral  Solutions,  Inc.  (MSSI) 
 9.  National  Association  of  Broadcasters  (NAB)  10.  Dr.  Gary  R.  Olhoeft 
 11.  Rockwell  Collins,  Inc.  12.  Sirius  Satellite  Radio  Inc.  (Sirius) 
 13.  Sprint  Corporation  14.  3Com  Corporation 
 15.  Time  Domain  Corporation  16.  U.  S.  GPS  Industry  Council 

 Parties  filing  reply  comments: 
 1.  AT&  T  Wireless  Services,  Inc.  (AT&  T)  2.  Fantasma  Networks,  Inc.  (Fantasma) 
 3.  Multispectral  Solutions,  Inc.  (MSSI)  4.  Sirius  Satellite  Radio  Inc.  (Sirius) 
 5.  Time  Domain  Corporation  6.  XM  Radio  Inc. 
 7.  XtremeSpectrum,  Inc. 
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 Appendix  C  Comments  in  Response  to  Studies  of  Potential  Interference  to  GPS  Systems  and  to  PCS 
 Parties  filing  comments: 
 1.  Aeronautical  Radio,  Inc.  and  The  Air  Transport  Association  of  America,  Inc.  (ARINC/  ATA)  2.  ANRO  Engineering,  Inc.  (ANRO) 
 3.  ARRL,  The  National  Association  for  Amateur  Radio  (ARRL)  4.  The  Boeing  Company  (Boeing) 
 5.  Centre  for  Sensor  Signal  and  Information  Processing  (CSSIP)  6.  Conexant  Systems  Inc. 
 7.  Geophysical  Survey  Systems,  Inc.  (GSSI)  (x2)  8.  The  Ground  Penetrating  Radar  Circle  of  Finland 
 9.  Johns  Hopkins  University  Applied  Physics  Laboratory  10.  Lockheed  Martin  Corporation  (LMC) 
 11.  Motorola,  Inc.  12.  Nokia,  Inc. 
 13.  Sirius  Satellite  Radio  Inc.  (Sirius)  (x2)  14.  Dr.  Lee  Slater 
 15.  Sprint  Corporation  (Sprint)  16.  Sprint  Spectrum  (Sprint  PCS) 
 17.  Dr.  Ben  K.  Sternberg  18.  Technos,  Inc. 
 19.  Time  Domain  Corporation  (TDC)  20.  U.  S.  GPS  Industry  Council 
 21.  Dr.  David  L.  Wright  22.  XtremeSpectrum,  Inc.  (x2) 

 Parties  filing  reply  comments: 
 1.  Aeronautical  Radio,  Inc.  and  The  Air  Transport  Association  of  America,  Inc.  (ARINC/  ATA)  2.  Dr.  A.  Peter  Annan 
 3.  ARRL,  The  National  Association  for  Amateur  Radio  (ARRL)  4.  Cingular  Wireless 
 5.  Common  Ground  Alliance  6.  Geophysics  Community 
 7.  Interagency  GPS  Executive  Board  (IGEB)  8.  Johns  Hopkins  University  Applied  Physics  Laboratory 
 9.  Mercedes-  Benz  USA  (MBUSA)  10.  Qualcomm  Incorporated 
 11.  Sirius  Satellite  Radio,  Inc.  12.  Society  of  Exploration  Geophysicists  (SEG) 
 13.  Time  Domain  Corporation  (TDC)  14.  U.  S.  GPS  Industry  Council 
 15.  XM  RadioInc.  16.  XtremeSpectrum,  Inc. 
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 Appendix  D  Changes  to  the  Regulations 
 Title  47  of  the  Code  of  Federal  Regulations,  Part  15,  is  amended  as  follows: 
 1.  The  authority  citation  for  Part  15  continues  to  read  as  follows: 
 AUTHORITY:  47  U.  S.  C.  154,  302,  303,  304,  307  and  544A. 
 2.  Section  15.35  is  amended  by  revising  paragraph  (b)  to  read  as  follows: 
 Section  15.35  Measurement  detector  function  and  bandwidth. 
 *  *  *  *  * 
 (b)  Unless  otherwise  stated,  on  any  frequency  or  frequencies  above  1000  MHz  the  radiated  limits  shown  are  based  upon  the  use  of  measurement  instrumentation  employing  an  average  detector  function. 
 When  average  radiated  emission  measurements  are  specified  in  the  regulations,  including  emission  measurements  below  1000  MHz,  there  also  is  a  limit  on  the  radio  frequency  emissions,  as  measured  using 
 instrumentation  with  a  peak  detector  function,  corresponding  to  20  dB  above  the  maximum  permitted  average  limit  for  the  frequency  being  investigated  unless  a  different  peak  emission  limit  is  otherwise 
 specified  in  the  rules,  e.  g.,  see  Sections  15.255,  15.509  and  15.511.  Unless  otherwise  specified,  measurements  above  1000  MHz  shall  be  performed  using  a  minimum  resolution  bandwidth  of  1  MHz. 
 Measurements  of  AC  power  line  conducted  emissions  are  performed  using  a  CISPR  quasi-  peak  detector,  even  for  devices  for  which  average  radiated  emission  measurements  are  specified. 

 *  *  *  *  * 
 3.  Section  15.205  is  amended  by  adding  a  new  subparagraph  (d)(  6),  to  read  as  follows: 
 Section  15.205  Restricted  bands  of  operation. 
 *  *  *  *  * 
 (d)(  6)  Transmitters  operating  under  the  provisions  of  Subparts  D  or  F  of  this  Part. 
 *  *  *  *  * 
 4.  Section  15.215  is  amended  by  revising  (c)  and  by  removing  paragraph  (d),  to  read  as  follows: 
 Section  15.215  Additional  provisions  to  the  general  radiated  emission  limitations. 
 *  *  *  *  * 
 (c)  Intentional  radiators  operating  under  the  alternative  provisions  to  the  general  emission  limits,  as  contained  in  Sections  15.217  et  seq.  and  in  Subpart  E  of  this  part,  must  be  designed  to  ensure  that  the  20 
 dB  bandwidth  of  the  emission  is  contained  within  the  frequency  band  designated  in  the  rule  section  under  which  the  equipment  is  operated.  The  requirement  to  contain  the  20  dB  bandwidth  of  the  emission  within 
 the  specified  frequency  band  includes  the  effects  from  frequency  sweeping,  frequency  hopping  and  other  modulation  techniques  that  may  be  employed  as  well  as  the  frequency  stability  of  the  transmitter  over 
 expected  variations  in  temperature  and  supply  voltage.  If  a  frequency  stability  is  not  specified  in  the 
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 regulations,  it  is  recommended  that  the  fundamental  emission  be  kept  within  at  least  the  central  80%  of  the  permitted  band  in  order  to  minimize  the  possibility  of  out-  of-  band  operation. 
 5.  Part  15  is  amended  by  adding  a  new  Subpart  F,  to  read  as  follows: 
 SUBPART  F    ULTRA-  WIDEBAND  OPERATION 
 Section  15.501  Scope. 
 This  subpart  sets  out  the  regulations  for  unlicensed  ultra-  wideband  transmission  systems. 
 Section  15.503  Definitions. 
 (a)  UWB  Bandwidth.  For  the  purpose  of  this  subpart,  the  UWB  bandwidth  is  the  frequency  band  bounded  by  the  points  that  are  10  dB  below  the  highest  radiated  emission,  as  based  on  the  complete 
 transmission  system  including  the  antenna.  The  upper  boundary  is  designated  fH  and  the  lower  boundary  is  designated  fL.  The  frequency  at  which  the  highest  radiated  emission  occurs  is  designated  fM. 

 (b)  Center  frequency.  The  center  frequency,  fC,  equals  (fH  +  fL)/  2. 
 (c)  Fractional  bandwidth.  The  fractional  bandwidth  equals  2(  fH  -  fL)/  (fH  +  fL). 
 (d)  Ultra-  wideband  (UWB)  transmitter.  An  intentional  radiator  that,  at  any  point  in  time,  has  a  fractional  bandwidth  equal  to  or  greater  than  0.20  or  has  a  UWB  bandwidth  equal  to  or  greater  than  500 
 MHz,  regardless  of  the  fractional  bandwidth. 
 (e)  Imaging  system.  A  general  category  consisting  of  ground  penetrating  radar  systems,  medical  imaging  systems,  wall  imaging  systems  through-  wall  imaging  systems  and  surveillance  systems.  As  used 
 in  this  subpart,  imaging  systems  do  not  include  systems  designed  to  detect  the  location  of  tags  or  systems  used  to  transfer  voice  or  data  information. 

 (f)  Ground  penetrating  radar  (GPR)  system.  A  field  disturbance  sensor  that  is  designed  to  operate  only  when  in  contact  with,  or  within  one  meter  of,  the  ground  for  the  purpose  of  detecting  or 
 obtaining  the  images  of  buried  objects  or  determining  the  physical  properties  within  the  ground.  The  energy  from  the  GPR  is  intentionally  directed  down  into  the  ground  for  this  purpose. 

 (g)  Medical  imaging  system.  A  field  disturbance  sensor  that  is  designed  to  detect  the  location  or  movement  of  objects  within  the  body  of  a  person  or  animal. 
 (h)  Wall  imaging  system.  A  field  disturbance  sensor  that  is  designed  to  detect  the  location  of  objects  contained  within  a  wall  or  to  determine  the  physical  properties  within  the  wall.  The  wall  is 
 a  concrete  structure,  the  side  of  a  bridge,  the  wall  of  a  mine  or  another  physical  structure  that  is  dense  enough  and  thick  enough  to  absorb  the  majority  of  the  signal  transmitted  by  the  imaging  system.  This 
 category  of  equipment  does  not  include  products  such  as  stud  locators  that  are  designed  to  locate  objects  behind  gypsum,  plaster  or  similar  walls  that  are  not  capable  of  absorbing  the  transmitted  signal. 

 (i)  Through-  wall  imaging  system.  A  field  disturbance  sensor  that  is  designed  to  detect  the  location  or  movement  of  persons  or  objects  that  are  located  on  the  other  side  of  an  opaque  structure  such 
 as  a  wall  or  a  ceiling.  This  category  of  equipment  may  include  products  such  as  stud  locators  that  are  designed  to  locate  objects  behind  gypsum,  plaster  or  similar  walls  that  are  not  thick  enough  or  dense 
 enough  to  absorb  the  transmitted  signal. 
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 (j)  Surveillance  system.  A  field  disturbance  sensor  used  to  establish  a  stationary  RF  perimeter  field  that  is  used  for  security  purposes  to  detect  the  intrusion  of  persons  or  objects. 
 (k)  EIRP.  Equivalent  isotropically  radiated  power,  i.  e.,  the  product  of  the  power  supplied  to  the  antenna  and  the  antenna  gain  in  a  given  direction  relative  to  an  isotropic  antenna.  The  EIRP,  in  terms  of 
 dBm,  can  be  converted  to  a  field  strength,  in  dBuV/  m  at  3  meters,  by  adding  95.  2.  As  used  in  this  subpart,  EIRP  refers  to  the  highest  signal  strength  measured  in  any  direction  and  at  any  frequency  from  the  UWB 
 device,  as  tested  in  accordance  with  the  procedures  specified  in  Sections  15.31(  a)  and  15.523  of  this  chapter. 

 (l)  Law  enforcement,  fire  and  emergency  rescue  organizations.  As  used  in  this  subpart,  this  refers  to  those  parties  eligible  to  obtain  a  license  from  the  FCC  under  the  eligibility  requirements 
 specified  in  Section  90.20(  a)(  1)  of  this  chapter. 
 (m)  Hand  held.  As  used  in  this  subpart,  a  hand  held  device  is  a  portable  device,  such  as  a  lap  top  computer  or  a  PDA,  that  is  primarily  hand  held  while  being  operated  and  that  does  not  employ  a  fixed 
 infrastructure. 
 Section  15.505  Cross  reference. 
 (a)  Except  where  specifically  stated  otherwise  within  this  subpart,  the  provisions  of  Subparts  A  and  B  and  of  Sections  15.201  through  15.  204  and  Section  15.207  of  Subpart  C  of  this  part  apply  to 
 unlicensed  UWB  intentional  radiators.  The  provisions  of  Sections  15.35(  c)  and  15.205  do  not  apply  to  devices  operated  under  this  subpart.  The  provisions  of  Footnote  US  246  to  the  Table  of  Frequency 
 Allocations  contained  in  Section  2.106  of  this  chapter  does  not  apply  to  devices  operated  under  this  subpart. 

 (b)  The  requirements  of  Subpart  F  apply  only  to  the  radio  transmitter,  i.  e.,  the  intentional  radiator,  contained  in  the  UWB  device.  Other  aspects  of  the  operation  of  a  UWB  device  may  be  subject 
 to  requirements  contained  elsewhere  in  this  chapter.  In  particular,  a  UWB  device  that  contains  digital  circuitry  not  directly  associated  with  the  operation  of  the  transmitter  also  is  subject  to  the  requirements  for 
 unintentional  radiators  in  Subpart  B  of  this  chapter.  Similarly,  an  associated  receiver  that  operates  (tunes)  within  the  frequency  range  30  MHz  to  960  MHz  is  subject  to  the  requirements  in  Subpart  B  of  this 
 chapter. 
 Section  15.507  Marketing  of  UWB  equipment. 
 In  some  cases,  the  operation  of  UWB  devices  is  limited  to  specific  parties,  e.  g.,  law  enforcement,  fire  and  rescue  organizations  operating  under  the  auspices  of  a  state  or  local  government.  The  marketing 
 of  UWB  devices  must  be  directed  solely  to  parties  eligible  to  operate  the  equipment.  The  responsible  party,  as  defined  in  Section  2.909  of  this  chapter,  is  responsible  for  ensuring  that  the  equipment  is 
 marketed  only  to  eligible  parties.  Marketing  of  the  equipment  in  any  other  manner  may  be  considered  grounds  for  revocation  of  the  grant  of  certification  issued  for  the  equipment. 

 Section  15.509  Technical  requirements  for  low  frequency  imaging  systems. 
 (a)  The  UWB  bandwidth  of  an  imaging  system  operating  under  the  provisions  of  this  Section  must  be  below  960  MHz. 

 (b)  Operation  under  the  provisions  of  this  section  is  limited  to  the  following: 
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 (1)  GPRs  and  wall  imaging  systems  operated  by  law  enforcement,  fire  and  emergency  rescue  organizations,  by  scientific  research  institutes,  by  commercial  mining  companies,  or  by 
 construction  companies. 
 (2)  Through-  wall  imaging  systems  operated  by  law  enforcement,  fire  or  emergency  rescue  organizations. 

 (3)  Parties  operating  this  equipment  must  be  eligible  for  licensing  under  the  provisions  of  Part  90  of  our  rules. 
 (4)  The  operation  of  imaging  systems  under  this  section  requires  coordination,  as  detailed  in  Section  15.525  of  this  chapter. 
 (c)  An  imaging  system  shall  contain  a  manually  operated  switch  that  causes  the  transmitter  to  cease  operation  within  10  seconds  of  being  released  by  the  operator.  In  addition,  it  is  permissible  to 
 operate  an  imaging  system  by  remote  control  provided  the  imaging  system  ceases  transmission  within  10  seconds  of  the  remote  switch  being  released  by  the  operator. 

 (d)  The  radiated  emissions  at  or  below  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  emission  levels  in  Section  15.209  of  this  chapter.  The  radiated  emissions 
 above  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when  measured  using  a  resolution  bandwidth  of  1  MHz: 

 Frequency  in  MHz  EIRP  in  dBm  960-  1610 
 1610-  1990  Above  1990  -65.3  -53.3  -51.3 

 (e)  In  addition  to  the  radiated  emission  limits  specified  in  the  above  table,  UWB  transmitters  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when 
 measured  using  a  resolution  bandwidth  of  no  less  than  1  kHz: 
 Frequency  in  MHz  EIRP  in  dBm  1164-  1240 
 1559-  1610  -75.3  -75.3 
 (f)  There  is  a  limit  on  the  peak  level  of  the  emissions  contained  within  a  50  MHz  bandwidth  centered  on  the  frequency  at  which  the  highest  radiated  emission  occurs,  fM.  That  limit  is  0  dBm  EIRP.  It 
 is  acceptable  to  employ  a  different  resolution  bandwidth,  and  a  correspondingly  different  peak  emission  limit,  following  the  procedures  described  in  Section  15.521  of  this  chapter. 

 (g)  Imaging  systems  operating  under  the  provisions  of  this  section  shall  bear  the  following  or  similar  statement,  as  adjusted  for  the  specific  provisions  in  paragraph  (b)  of  this  section,  in  a  conspicuous 
 location  on  the  device: 
 Operation  of  this  device  is  restricted  to  law  enforcement,  fire  and  rescue  officials,  scientific  research  institutes,  commercial  mining  companies,  and  construction  companies. 
 Operation  by  any  other  party  is  a  violation  of  47  U.  S.  C.    301  and  could  subject  the  operator  to  serious  legal  penalties. 

 Section  15.511  Technical  requirements  for  mid-  frequency  imaging  systems. 
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 (a)  The  UWB  bandwidth  of  an  imaging  system  operating  under  the  provisions  of  this  section  must  be  contained  between  1990  MHz  and  10,600  MHz. 
 (b)  Operation  under  the  provisions  of  this  section  is  limited  to  the  following: 
 (1)  Through-  wall  imaging  systems  operated  by  law  enforcement,  fire  or  emergency  rescue  organizations. 

 (2)  Fixed  surveillance  systems  operated  by  law  enforcement,  fire  or  emergency  rescue  organizations  or  by  manufacturers  licensees,  petroleum  licensees  or  power  licensees  as  defined  in  Section 
 90.7  of  this  chapter. 
 (3)  Parties  operating  under  the  provisions  of  this  section  must  be  eligible  for  licensing  under  the  provisions  of  Part  90  of  our  rules. 

 (4)  The  operation  of  imaging  systems  under  this  section  requires  coordination,  as  detailed  in  Section  15.525  of  this  chapter. 
 (c)  A  through-  wall  imaging  system  shall  contain  a  manually  operated  switch  that  causes  the  transmitter  to  cease  operation  within  10  seconds  of  being  released  by  the  operator.  In  addition,  it  is 
 permissible  to  operate  an  imaging  system  by  remote  control  provided  the  imaging  system  ceases  transmission  within  10  seconds  of  the  remote  switch  being  released  by  the  operator. 

 (d)  The  radiated  emissions  at  or  below  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  emission  levels  in  Section  15.209  of  this  chapter.  The  radiated  emissions 
 above  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when  measured  using  a  resolution  bandwidth  of  1  MHz: 

 Frequency  in  MHz  EIRP  in  dBm  960-  1610 
 1610-  1990  1990-  10600 
 Above  10600 

 -53.3  -51.3 
 -41.3  -51.3 

 (e)  In  addition  to  the  radiated  emission  limits  specified  in  the  above  table,  UWB  transmitters  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when 
 measured  using  a  resolution  bandwidth  of  no  less  than  1  kHz: 
 Frequency  in  MHz  EIRP  in  dBm  1164-  1240 
 1559-  1610  -63.3  -63.3 
 (f)  There  is  a  limit  on  the  peak  level  of  the  emissions  contained  within  a  50  MHz  bandwidth  centered  on  the  frequency  at  which  the  highest  radiated  emission  occurs,  fM.  That  limit  is  0  dBm  EIRP.  It 
 is  acceptable  to  employ  a  different  resolution  bandwidth,  and  a  correspondingly  different  peak  emission  limit,  following  the  procedures  described  in  Section  15.521  of  this  chapter. 

 (g)  Imaging  systems  operating  under  the  provisions  of  this  section  shall  bear  the  following  or  similar  statement,  as  adjusted  for  the  specific  provisions  in  paragraph  (b)  of  this  section,  in  a  conspicuous 
 location  on  the  device: 
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 Operation  of  this  device  is  restricted  to  law  enforcement,  fire  and  rescue  officials,  public  utilities,  and  industrial  entities.  Operation  by  any  other  party  is  a  violation  of  47  U.  S.  C.   
 301  and  could  subject  the  operator  to  serious  legal  penalties. 
 Section  15.513  Technical  requirements  for  high  frequency  imaging  systems. 
 (a)  The  UWB  bandwidth  of  an  imaging  system  operating  under  the  provisions  of  this  section  must  be  contained  between  3100  MHz  and  10,600  MHz. 

 (b)  Operation  under  the  provisions  of  this  section  is  limited  to  the  following: 
 (1)  GPRs  and  wall  imaging  systems  operated  by  law  enforcement,  fire  or  emergency  rescue  organizations,  by  scientific  research  institutes,  by  commercial  mining  companies,  or  by 
 construction  companies. 
 (2)  Medical  imaging  systems  used  at  the  direction  of,  or  under  the  supervision  of,  a  licensed  health  care  practitioner. 

 (3)  Parties  operating  GPRs  or  wall  imaging  systems  must  be  eligible  for  licensing  under  the  provisions  of  Part  90  of  our  rules. 
 (4)  The  operation  of  imaging  systems  under  this  section  requires  coordination,  as  detailed  in  Section  15.525  of  this  chapter. 
 (c)  An  imaging  system  shall  contain  a  manually  operated  switch  that  causes  the  transmitter  to  cease  operation  within  10  seconds  of  being  released  by  the  operator.  In  addition,  it  is  permissible  to 
 operate  an  imaging  system  by  remote  control  provided  the  imaging  system  ceases  transmission  within  10  seconds  of  the  remote  switch  being  released  by  the  operator. 

 (d)  The  radiated  emissions  at  or  below  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  emission  levels  in  Section  15.209  of  this  chapter.  The  radiated  emissions 
 above  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when  measured  using  a  resolution  bandwidth  of  1  MHz: 

 Frequency  in  MHz  EIRP  in  dBm  960-  1610 
 1610-  1990  1990-  3100 
 3100-  10600  Above  10600 

 -65.3  -53.3 
 -51.3  -41.3 
 -51.3 
 (e)  In  addition  to  the  radiated  emission  limits  specified  in  the  above  table,  UWB  transmitters  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when 
 measured  using  a  resolution  bandwidth  of  no  less  than  1  kHz: 
 Frequency  in  MHz  EIRP  in  dBm  1164-  1240 
 1559-  1610  -75.3  -75.3 
 (f)  There  is  a  limit  on  the  peak  level  of  the  emissions  contained  within  a  50  MHz  bandwidth  centered  on  the  frequency  at  which  the  highest  radiated  emission  occurs,  fM.  That  limit  is  0  dBm  EIRP.  It 
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 is  acceptable  to  employ  a  different  resolution  bandwidth,  and  a  correspondingly  different  peak  emission  limit,  following  the  procedures  described  in  Section  15.521  of  this  chapter. 
 (g)  Imaging  systems,  other  than  medical  imaging  systems,  operating  under  the  provisions  of  this  section  shall  bear  the  following  or  similar  statement  in  a  conspicuous  location  on  the  device: 
 Operation  of  this  device  is  restricted  to  law  enforcement,  fire  and  rescue  officials,  scientific  research  institutes,  commercial  mining  companies,  and  construction  companies. 
 Operation  by  any  other  party  is  a  violation  of  47  U.  S.  C.    301  and  could  subject  the  operator  to  serious  legal  penalties. 

 Section  15.515  Technical  requirements  for  vehicular  radar  systems. 
 (a)  Operation  under  the  provisions  of  this  section  is  limited  to  UWB  field  disturbance  sensors  mounted  in  terrestrial  transportation  vehicles.  These  devices  shall  operate  only  when  the  vehicle  is 
 operating,  e.  g.,  the  engine  is  running.  Operation  shall  occur  only  upon  specific  activation,  such  as  upon  starting  the  vehicle,  changing  gears,  or  engaging  a  turn  signal. 

 (b)  The  UWB  bandwidth  fo  a  vehicular  radar  system  operating  under  the  provisions  of  this  section  shall  be  contained  between  22  GHz  and  29  GHz.  In  addition,  the  center  frequency,  fC,  and  the 
 frequency  at  which  the  highest  level  emission  occurs,  fM,  must  be  greater  than  24.075  GHz. 
 (c)  Following  proper  installation,  vehicular  radar  systems  shall  attenuate  any  emissions  within  the  23.6-  24.0  GHz  band  that  appear  38  degrees  or  greater  above  the  horizontal  plane  by  25  dB  below  the 
 limit  specified  in  paragraph  (d)  of  this  chapter.  For  equipment  authorized,  manufactured  or  imported  on  or  after  January  1,  2005,  this  level  of  attenuation  shall  be  25  dB  for  any  emissions  within  the  23.  6-  24.  0 
 GHz  band  that  appear  30  degrees  or  greater  above  the  horizontal  plane.  For  equipment  authorized,  manufactured  or  imported  on  or  after  January  1,  2010,  this  level  of  attenuation  shall  be  30  dB  for  any 
 emissions  within  the  23.6-  24.0  GHz  band  that  appear  30  degrees  or  greater  above  the  horizontal  plane.  For  equipment  authorized,  manufactured  or  imported  on  or  after  January  1,  2014,  this  level  of  attenuation 
 shall  be  35  dB  for  any  emissions  within  the  23.6-  24.0  GHz  band  that  appear  30  degrees  or  greater  above  the  horizontal  plane.  This  level  of  attenuation  can  be  achieved  through  the  antenna  directivity,  through  a 
 reduction  in  output  power  or  any  other  means. 
 (d)  The  radiated  emissions  at  or  below  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  emission  levels  in  Section  15.209  of  this  chapter.  The  radiated  emissions 
 above  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when  measured  using  a  resolution  bandwidth  of  1  MHz: 

 Frequency  in  MHz  EIRP  in  dBm  960-  1610 
 1610-  22,000  22,000-  29,  000 
 29,000-  31,  000  Above  31,000 

 -75.3  -61.3 
 -41.3  -51.3 
 -61.3 
 (e)  In  addition  to  the  radiated  emission  limits  specified  in  the  above  table,  UWB  transmitters  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when 
 measured  using  a  resolution  bandwidth  of  no  less  than  1  kHz: 
 Frequency  in  MHz  EIRP  in  dBm  1164-  1240  -85.3 
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 1559-  1610  -85.3 
 (f)  There  is  a  limit  on  the  peak  level  of  the  emissions  contained  within  a  50  MHz  bandwidth  centered  on  the  frequency  at  which  the  highest  radiated  emission  occurs,  fM.  That  limit  is  0  dBm  EIRP.  It 
 is  acceptable  to  employ  a  different  resolution  bandwidth,  and  a  correspondingly  different  peak  emission  limit,  following  the  procedures  described  in  Section  15.521  of  this  chapter. 

 Section  15.517  Technical  requirements  for  indoor  UWB  systems. 
 (a)  Operation  under  the  provisions  of  this  section  is  limited  to  UWB  transmitters  employed  solely  for  indoor  operation. 

 (1)  Indoor  UWB  devices,  by  the  nature  of  their  design,  must  be  capable  of  operation  only  indoors.  The  necessity  to  operate  with  a  fixed  indoor  infrastructure,  e.  g.,  a  transmitter  that  must  be 
 connected  to  the  AC  power  lines,  may  be  considered  sufficient  to  demonstrate  this. 
 (2)  The  emissions  from  equipment  operated  under  this  section  shall  not  be  intentionally  directed  outside  of  the  building  in  which  the  equipment  is  located,  such  as  through  a  window  or  a 
 doorway,  to  perform  an  outside  function,  such  as  the  detection  of  persons  about  to  enter  a  building. 
 (3)  The  use  of  outdoor  mounted  antennas,  e.  g.,  antennas  mounted  on  the  outside  of  a  building  or  on  a  telephone  pole,  or  any  other  outdoors  infrastructure  is  prohibited. 

 (4)  Field  disturbance  sensors  installed  inside  of  metal  or  underground  storage  tanks  are  considered  to  operate  indoors  provided  the  emissions  are  directed  towards  the  ground. 
 (5)  A  communications  system  shall  transmit  only  when  the  intentional  radiator  is  sending  information  to  an  associated  receiver. 
 (b)  The  UWB  bandwidth  of  a  UWB  system  operating  under  the  provisions  of  this  section  must  be  contained  between  3100  MHz  and  10,600  MHz. 
 (c)  The  radiated  emissions  at  or  below  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  emission  levels  in  Section  15.209  of  this  chapter.  The  radiated  emissions 
 above  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when  measured  using  a  resolution  bandwidth  of  1  MHz: 

 Frequency  in  MHz  EIRP  in  dBm  960-  1610 
 1610-  1990  1990-  3100 
 3100-  10600  Above  10600 

 -75.3  -53.3 
 -51.3  -41.3 
 -51.3 
 (e)  In  addition  to  the  radiated  emission  limits  specified  in  the  above  table,  UWB  transmitters  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when 
 measured  using  a  resolution  bandwidth  of  no  less  than  1  kHz: 
 Frequency  in  MHz  EIRP  in  dBm  1164-  1240 
 1559-  1610  -85.3  -85.3 
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 (f)  There  is  a  limit  on  the  peak  level  of  the  emissions  contained  within  a  50  MHz  bandwidth  centered  on  the  frequency  at  which  the  highest  radiated  emission  occurs,  fM.  That  limit  is  0  dBm  EIRP.  It 
 is  acceptable  to  employ  a  different  resolution  bandwidth,  and  a  correspondingly  different  peak  emission  limit,  following  the  procedures  described  in  Section  15.521  of  this  chapter. 

 (g)  UWB  systems  operating  under  the  provisions  of  this  section  shall  bear  the  following  or  similar  statement  in  a  conspicuous  location  on  the  device  or  in  the  instruction  manual  supplied  with  the 
 device: 
 This  equipment  may  only  be  operated  indoors.  Operation  outdoors  is  in  violation  of  47  U.  S.  C.    301  and  could  subject  the  operator  to  serious  legal  penalties. 

 Section  15.519  Technical  requirements  for  hand  held  UWB  systems. 
 (a)  UWB  devices  operating  under  the  provisions  of  this  section  must  be  hand  held,  i.  e.,  they  are  relatively  small  devices  that  are  primarily  hand  held  while  being  operated  and  do  not  employ  a  fixed 
 infrastructure. 
 (1)  A  UWB  device  operating  under  the  provisions  of  this  section  shall  transmit  only  when  it  is  sending  information  to  an  associated  receiver.  The  UWB  intentional  radiator  shall  cease 
 transmission  within  10  seconds  unless  it  receives  an  acknowledgement  from  the  associated  receiver  that  its  transmission  is  being  received.  An  acknowledgment  of  reception  must  continued  to  be  received  by  the 
 UWB  intentional  radiator  at  least  every  10  seconds  or  the  UWB  device  must  cease  transmitting. 
 (2)  The  use  of  antennas  mounted  on  outdoor  structures,  e.  g.,  antennas  mounted  on  the  outside  of  a  building  or  on  a  telephone  pole,  or  any  fixed  outdoors  infrastructure  is  prohibited.  Antennas 
 may  be  mounted  only  on  the  hand  held  UWB  device. 
 (3)  UWB  devices  operating  under  the  provisions  of  this  section  may  operate  indoors  or  outdoors. 

 (b)  The  UWB  bandwidth  of  a  device  operating  under  the  provisions  of  this  Section  must  be  contained  between  3100  MHz  and  10,600  MHz. 
 (c)  The  radiated  emissions  at  or  below  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  emission  levels  in  Section  15.209  of  this  chapter.  The  radiated  emissions 
 above  960  MHz  from  a  device  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when  measured  using  a  resolution  bandwidth  of  1  MHz: 

 Frequency  in  MHz  EIRP  in  dBm  960-  1610 
 1610-  1900  1900-  3100 
 3100-  10600  Above  10600 

 -75.3  -63.3 
 -61.3  -41.3 
 -61.3 
 (d)  In  addition  to  the  radiated  emission  limits  specified  in  the  above  table,  UWB  transmitters  operating  under  the  provisions  of  this  section  shall  not  exceed  the  following  average  limits  when 
 measured  using  a  resolution  bandwidth  of  no  less  than  1  kHz: 
 Frequency  in  MHz  EIRP  in  dBm  1164-  1240  -85.3 
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 1559-  1610  -85.3 
 (e)  There  is  a  limit  on  the  peak  level  of  the  emissions  contained  within  a  50  MHz  bandwidth  centered  on  the  frequency  at  which  the  highest  radiated  emission  occurs,  fM.  That  limit  is  0  dBm  EIRP.  It 
 is  acceptable  to  employ  a  different  resolution  bandwidth,  and  a  correspondingly  different  peak  emission  limit,  following  the  procedures  described  in  Section  15.521  of  this  chapter. 

 Section  15.521  Technical  requirements  applicable  to  all  UWB  devices. 
 (a)  UWB  devices  may  not  be  employed  for  the  operation  of  toys.  Operation  onboard  an  aircraft,  a  ship  or  a  satellite  is  prohibited. 

 (b)  Manufacturers  and  users  are  reminded  of  the  provisions  of  Sections  15.203  and  15.  204  of  this  chapter. 
 (c)  As  noted  in  Section  15.3(  k)  of  this  chapter,  digital  circuitry  that  is  used  only  to  enable  the  operation  of  a  transmitter  and  that  does  not  control  additional  functions  or  capabilities  is  not  classified  as 
 a  digital  device.  Instead,  the  emissions  from  that  digital  circuitry  are  subject  to  the  same  limits  as  those  applicable  to  the  transmitter.  If  it  can  be  clearly  demonstrated  that  an  emission  from  a  UWB  transmitter 
 is  due  solely  to  emissions  from  digital  circuitry  contained  within  the  transmitter  and  that  the  emission  is  not  intended  to  be  radiated  from  the  transmitters  antenna,  the  limits  shown  in  Section  15.209  of  this 
 chapter  shall  apply  to  that  emission  rather  than  the  limits  specified  in  this  section. 
 (d)  Within  the  tables  in  the  above  rule  sections,  the  tighter  emission  limit  applies  at  the  band  edges.  Radiated  emission  levels  at  and  below  960  MHz  are  based  on  measurements  employing  a  CISPR 
 quasi-  peak  detector.  Radiated  emission  levels  above  960  MHz  are  based  on  RMS  average  measurements  over  a  1  MHz  resolution  bandwidth.  The  RMS  average  measurement  is  based  on  the  use  of  a  spectrum 
 analyzer  with  a  resolution  bandwidth  of  1  MHz,  an  RMS  detector,  and  a  1  millisecond  or  less  averaging  time.  If  pulse  gating  is  employed  where  the  transmitter  is  quiescent  for  intervals  that  are  long  compared 
 to  the  nominal  pulse  repetition  interval,  measurements  shall  be  made  with  the  pulse  train  gated  on.  Alternative  measurement  procedures  may  be  considered  by  the  Commission. 

 (e)  The  frequency  at  which  the  highest  radiated  emission  occurs,  fM,  must  be  contained  within  the  UWB  bandwidth. 
 (f)  Imaging  systems  may  be  employed  only  for  the  type  of  information  exchange  described  in  their  specific  definitions  contained  in  Section  15.503  of  this  chapter.  The  detection  of  tags  or  the  transfer 
 or  data  or  voice  information  is  not  permitted  under  the  standards  for  imaging  systems. 
 (g)  When  a  peak  measurement  is  required,  it  is  acceptable  to  use  a  resolution  bandwidth  other  than  the  50  MHz  specified  in  this  subpart.  This  resolution  bandwidth  shall  not  be  lower  than  1  MHz  or 
 greater  than  50  MHz,  and  the  measurement  shall  be  centered  on  the  frequency  at  which  the  highest  radiated  emission  occurs,  fM.  If  a  resolution  bandwidth  other  than  50  MHz  is  employed,  the  peak  EIRP 
 limit  shall  be  20  log  (RBW/  50)  dBm  where  RBW  is  the  resolution  bandwidth  in  megahertz  that  is  employed.  This  may  be  converted  to  a  peak  field  strength  level  at  3  meters  using  E(  dBuV/  m)  =  P(  dBm 
 EIRP)  +  95.2.  If  RBW  is  greater  than  3  MHz,  the  application  for  certification  filed  with  the  Commission  must  contain  a  detailed  description  of  the  test  procedure,  calibration  of  the  test  setup,  and  the 
 instrumentation  employed  in  the  testing. 
 (h)  The  highest  frequency  employed  in  Section  15.33  of  this  chapter  to  determine  the  frequency  range  over  which  radiated  measurements  are  made  shall  be  based  on  the  center  frequency,  fC,  unless  a 
 higher  frequency  is  generated  within  the  UWB  device.  For  measuring  emission  levels,  the  spectrum  shall 
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 be  investigated  from  the  lowest  frequency  generated  in  the  UWB  transmitter,  without  going  below  9  kHz,  up  to  the  frequency  range  shown  in  Section  15.  33(  a)  of  this  chapter  or  up  to  fC  +  3/(  pulse  width  in 
 seconds),  whichever  is  higher.  There  is  no  requirement  to  measure  emissions  beyond  40  GHz  provided  fC  is  less  than  10  GHz;  beyond  100  GHz  if  fC  is  at  or  above  10  GHz  and  below  30  GHz;  or  beyond  200  GHz 
 if  fC  is  at  or  above  30  GHz. 
 (i)  The  prohibition  in  Sections  2.201(  f)  and  15.5(  d)  of  this  chapter  against  Class  B  (damped  wave)  emissions  does  not  apply  to  UWB  devices  operating  under  this  subpart. 

 (j)  Responsible  parties  are  reminded  of  the  other  standards  and  requirements  incorporated  by  reference  in  Section  15.505  of  this  chapter,  such  as  a  limit  on  emissions  conducted  onto  the  AC  power 
 lines. 
 Section  15.523  Measurement  procedures. 
 Measurements  shall  be  made  in  accordance  with  the  procedures  specified  by  the  Commission. 
 Section  15.525  Coordination  requirements. 
 (a)  UWB  imaging  systems  require  coordination  through  the  FCC  before  the  equipment  may  be  used.  The  operator  shall  comply  with  any  constraints  on  equipment  usage  resulting  from  this 
 coordination. 
 (b)  The  users  of  UWB  imaging  devices  shall  supply  detailed  operational  areas  to  the  FCC  Office  of  Engineering  and  Technology  who  shall  coordinate  this  information  with  the  Federal  Government 
 through  the  National  Telecommunications  and  Information  Administration.  The  information  provided  by  the  UWB  operator  shall  include  the  name,  address  and  other  pertinent  contact  information  of  the  user,  the 
 desired  geographical  area  of  operation,  and  the  FCC  ID  number  and  other  nomenclature  of  the  UWB  device.  This  material  shall  be  submitted  to  the  following  address: 

 Frequency  Coordination  Branch.,  OET  Federal  Communications  Commission 
 445  12  th  Street,  SW  Washington,  D.  C.  20554 

 ATTN:  UWB  Coordination 
 (c)  The  manufacturers,  or  their  authorized  sales  agents,  must  inform  purchasers  and  users  of  their  systems  of  the  requirement  to  undertake  detailed  coordination  of  operational  areas  with  the  FCC  prior  to 
 the  equipment  being  operated. 
 (d)  Users  of  authorized,  coordinated  UWB  systems  may  transfer  them  to  other  qualified  users  and  to  different  locations  upon  coordination  of  change  of  ownership  or  location  to  the  FCC  and 
 coordination  with  existing  authorized  operations. 
 (e)  The  NTIA/  FCC  coordination  report  shall  include  any  needed  constraints  that  apply  to  day-  to-day  operations.  Such  constraints  could  specify  prohibited  areas  of  operations  or  areas  located  near 
 authorized  radio  stations  for  which  additional  coordination  is  required  before  operation  of  the  UWB  equipment.  If  additional  local  coordination  is  required,  a  local  coordination  contact  will  be  provided. 

 (f)  The  coordination  of  routine  UWB  operations  shall  not  take  longer  than  15  business  days  from  the  receipt  of  the  coordination  request  by  NTIA.  Special  temporary  operations  may  be  handled  with  an 
 expedited  turn-  around  time  when  circumstances  warrant.  The  operation  of  UWB  systems  in  emergency 
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 situations  involving  the  safety  of  life  or  property  may  occur  without  coordination  provided  a  notification  procedure,  similar  to  that  contained  in  Section  2.405(  a)-(  e)  of  this  chapter,  is  followed  by  the  UWB 
 equipment  user. 
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 APPENDIX  E  Peak  in  a  Specific  Bandwidth  vs.  Average  in  a  1  MHz  Bandwidth  vs.  PRF 
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 APPENDIX  F  Measurement  Procedures 
 This  appendix  is  intended  to  provide  general  guidance  for  compliance  measurements  of  UWB  devices.  The  procedures  herein  are  based  on  the  Commissions  current  understanding  of  UWB  technology. 
 Modifications  may  be  necessary  as  measurement  experience  is  gained. 
 Except  as  otherwise  described  herein,  measurements  shall  be  made  in  accordance  with  the  procedures  specified  in  Section  15.31(  a)(  6)  of  Title  47  of  the  Code  of  Federal  Regulations. 

 (1)  Ground  penetrating  radars  (GPRs)  and  wall  imaging  systems  shall  be  tested  under  conditions  that  are  representative  of  actual  operating  conditions.  UWB  devices  intended  for  these  types 
 of  application  shall  be  compliance  tested  with  the  transducer  at  an  operationally  representative  height  above  a  twenty-  inch  thick  bed  of  dry  sand.  The  use  of  this  medium, 
 particularly  for  larger  GPRs  (e.  g.,  those  that  are  towed  behind  vehicles),  will  likely  preclude  the  use  of  a  turntable  in  the  measurement  procedure.  For  these  cases,  directionality  gradients 
 shall  be  analyzed  and  measurements  shall  be  performed  at  a  sufficient  number  of  radials  around  the  equipment  under  test  to  determine  the  radial  at  which  the  field  strength  values  of 
 the  radiated  emissions  are  maximized. 
 (2)  Field  strength  measurements  of  through-  wall  imaging  systems  may  be  made  with  a    thick  gypsum  or  drywall  board  placed  between  the  UWB  device  antenna  and  the  measurement 
 system  antenna. 
 (3)  RMS  average  field  strength  measurements,  required  for  all  frequencies  above  960  MHz,  shall  be  made  using  techniques  to  obtain  true  RMS  average.  This  can  be  accomplished  by  using  a 
 spectrum  analyzer  that  incorporates  a  RMS  detector.  The  resolution  bandwidth  of  the  analyzer  shall  be  set  to  1  MHz,  the  RMS  detector  selected,  and  a  video  integration  time  of  1 
 ms  or  less  is  to  be  used.  If  the  transmitter  employs  pulse  gating,  in  which  the  transmitter  is  quiescent  for  intervals  that  are  long  compared  to  the  nominal  pulse  repetition  interval,  all 
 measurements  shall  be  made  while  the  pulse  train  is  gated  on.  Alternatively,  a  true  RMS  level  can  be  measured  using  a  spectrum  analyzer  that  does  not  incorporate  a  RMS  detector. 
 This  approach  requires  a  multiple  step  technique  beginning  with  a  peak  detection  scan  of  the  UWB  spectrum  with  a  RBW  of  1  MHz  and  a  VBW  of  no  less  than  1  MHz.  The  resulting 
 trace  is  to  be  used  to  identify  the  frequency  and  bandwidth  of  the  five  highest  peaks  in  the  spectrum.  The  analyzer  is  then  to  be  placed  in  a  zero  span  mode,  with  a  RBW  of  1  MHz,  a 
 video  bandwidth  equal  to  or  greater  than  1  MHz,  and  a  detector  selected  that  does  not  distort  or  smooth  the  instantaneous  signal  levels  (e.  g.,  a  sample  detector).  With  these  settings,  a 
 minimum  of  ten  independent  instantaneous  points,  representing  the  highest  amplitude  readings,  are  to  be  obtained  during  the  time  that  a  pulse  is  present,  in  each  1  MHz  frequency 
 bin  across  the  bandwidth  of  each  of  the  five  highest  peaks  identified  in  the  previous  step.  Note  that  when  the  PRF  of  the  device  under  test  is  less  than  the  measurement  bandwidth  of  1 
 MHz,  a  significant  number  of  samples  may  be  required  to  ensure  that  a  minimum  of  10  samples  with  the  pulse  present  are  obtained.  The  data  obtained  from  these  measurements 
 must  then  be  post-  processed  to  determine  true  RMS  average  power  levels.  The  post-processing  of  the  data  can  be  performed  manually  or  with  the  aid  of  appropriate  software. 

 (4)  On  any  frequency  or  frequencies  below  or  equal  to  960  MHz,  the  field  strength  shall  be  measured  with  equipment  employing  a  CISPR  quasi-  peak  detector  function  and  related 
 measurement  bandwidths,  unless  otherwise  specified. 
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 (5)  In  the  frequency  bands  1164-  1240  MHz  and  1559-  1610  MHz,  average  radiated  field  strength  measurements  shall  be  made  with  a  resolution  bandwidth  of  no  less  than  1  kHz,  using 
 techniques  as  described  previously  for  determining  true  RMS  average  power  levels. 
 (6)  Peak  radiated  emission  measurements  shall  be  made  using  a  spectrum  analyzer  with  a  3  MHz  resolution  bandwidth  and  no  less  than  a  3  MHz  video  bandwidth.  The  analyzer  should  be 
 used  in  a  maximum-  hold  trace  mode.  The  peak  power  level  expressed  in  a  3  MHz  bandwidth  and  the  frequency  at  which  this  level  was  measured  shall  be  reported  in  the  application  for 
 certification.  A  different  resolution  bandwidth  between  1  MHz  and  50  MHz  may  be  employed  with  appropriate  changes  to  the  standard.  If  a  resolution  bandwidth  greater  than  3 
 MHz  is  employed,  a  detailed  description  of  the  test  procedure,  calibration  of  the  test  setup,  and  the  instrumentation  employed  in  the  testing  must  be  submitted  to  the  Commission.  It  is 
 recommended  that  measurements  using  a  resolution  bandwidth  greater  than  3  MHz  be  coordinated  with  the  Commissions  laboratory  staff  in  advance  of  the  submission  for 
 certification. 
 (7)  Field  strength  measurements  may  be  performed  without  the  use  of  a  ground  plane;  however,  a  factor  of  4.7  dB  must  be  added  to  the  measurement  results  thus  obtained. 

 (8)  To  the  extent  practicable,  the  device  under  test  should  be  measured  at  the  distance  specified  in  the  appropriate  rule  section.  However,  in  order  to  obtain  an  adequate  signal-  to-  noise  ratio 
 in  the  measurement  system,  radiated  measurements  may  have  to  be  made  at  distances  less  than  specified.  In  these  cases,  measurements  may  be  performed  at  a  distance  other  than  what 
 is  specified,  provided:  measurements  are  not  made  in  the  near  field  of  the  measurement  or  device  under  test  antenna,  except  where  it  can  be  shown  that  near  field  measurements  are 
 appropriate  due  to  the  characteristics  of  the  device;  and,  it  can  be  demonstrated  that  the  signal  levels  necessitated  a  measurement  at  the  distance  employed  in  order  to  be  accurately  detected 
 by  the  measurement  equipment. 
 (9)  To  the  maximum  extent  possible,  field  strength  measurements  should  be  performed  with  the  equipment  under  test  positioned  as  it  is  intended  to  be  used  in  actual  operating  conditions. 

 (10)  Radiated  field  strength  measurements  must  be  made  using  the  antenna  to  be  employed  with  the  UWB  device  under  test.  The  measurement  antenna  must  be  sufficiently  broad  band 
 to  cover  the  frequency  range  of  the  measurements,  and  the  use  of  multiple  measurement  antennas  may  be  required.  All  measurement  antennas  used  must  be  accurately  calibrated  and 
 must  demonstrate  low  phase  dispersion  over  the  frequency  range  of  measurement.  The  orientation  of  the  measurement  antenna  shall  be  varied  to  determine  the  polarization  that 
 maximizes  the  measured  field  strength. 
 (11)  The  spectrum  to  be  investigated  should  include  at  least  the  fundamental  emission  and  the  secondary  lobe  regardless  of  the  center  frequency.  In  order  to  accomplish  this,  the  frequency 
 spectrum  shall  be  investigated  from  the  lowest  frequency  generated  within  the  device,  without  going  below  9  kHz,  up  to  the  frequency  range  shown  in  Section  15.33(  a)  of  the  FCC 
 rules  or  up  to  an  upper  frequency  defined  by  adding  three  divided  by  the  pulse  width  in  seconds  to  the  center  frequency  in  Hz,  whichever  is  greater.  The  frequency  range  in  Section 
 15.33(  a)  is  based  on  the  center  frequency  unless  a  higher  frequency,  e.  g.,  a  carrier  frequency,  is  generated  within  the  device.  There  is  no  requirement  to  measure  emissions  beyond  40  GHz 
 provided  the  center  frequency  is  less  than  10  GHz;  beyond  100  GHz  if  the  center  frequency  is  at  or  above  10  GHz  and  below  30  GHz;  or  beyond  200  GHz  if  the  center  frequency  is  at  or 
 above  30  GHz. 
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 SEPARATE  STATEMENT  OF  COMMISSIONER  MICHAEL  J.  COPPS 
 February  14,  2002 
 RE:  Revision  of  Part  15  of  the  Commissions  Rules  Regarding  Ultra-  Wideband  Transmission  Systems  (ET  Docket  No.  98-  153) 

 I  believe  that  ultra-  wideband  (  UWB)  technologies  are  destined  to  play  a  significant  role  across  Americas  communications  landscape.  UWB  devices  will  save  firefighters  and  policemens  lives, 
 prevent  automobile  accidents,  assist  search-  and-  rescue  crews  in  seeing  through  the  rubble  of  disaster  sites,  enable  broadband  connections  between  our  home  electronics,  and  allow  exciting  new  forms  of 
 communications  in  the  years  ahead.  Indeed,  the  U.  S.  Government  already  uses  UWB  extensively  to  make  our  soldiers,  airport  runways,  and  highway  bridges  safer,  and  so  much  more  is  on  the  horizon. 

 But  opinion  differs  greatly  on  the  interference  effect  of  the  widespread  use  of  UWB  technologies  by  the  public.  If  interference  does  occur,  it  could  conceivably  affect  critical  government  and  non-government 
 spectrum  users.  Our  national  defense  and  several  safety-  of-  life  systems  depend  on  bands  that  have  the  potential  to  be  impacted  by  UWB  devices. 

 Because  the  effects  of  widespread  use  of  UWB  are  not  yet  fully  known,  and  interference  could  impact  critical  spectrum  users,  I  will  support,  albeit  somewhat  reluctantly,  the  ultra-  conservative  ultra-wideband 
 step  we  take  today.  The  limits  we  place  on  UWB  are  designed  to  reduce  the  interference  risks  associated  with  the  technology  to  levels  far,  far  below  those  placed  on  technologies  that  place  energy  into 
 narrower  portions  of  the  spectrum.  These  limits  are  intentionally  at  the  extreme  end  of  what  FCC  engineers    the  best  spectrum  engineers  in  the  country    believe  necessary.  They  were  agreed  to  because 
 of  the  unique  and  novel  impact  of  this  technology,  and  should  not  be  taken  as  precedent  for  any  other  interference  dispute    involving  other  Part  15  devices,  government  bands,  or  other  new  technologies. 

 I  strongly  support  the  Commissions  decision  to  initiate  a  further  NPRM  within  6  to  12  months.  My  hope  is  that  we  can  phase  in  this  exciting  new  technology  with  some  sense  of  urgency,  proceeding 
 through  the  conduct  of  expeditious  step-  by-  step  authorizations  from  the  Commission  for  applications  that  are  waiting  in  line.  We  owe  it  to  our  citizens  and  our  businesses  to  determine,  just  as  quickly  as  we 
 prudently  can,  whether  we  can  loosen  the  ultra-  conservative  restrictions  we  put  in  place  today.  So  I  urge  all  parties,  especially  our  government  colleagues,  to  start  collecting  data  immediately  so  we  can  have  as 
 much  data  as  possible,  including  information  about  their  own  use  of  UWB  and  how  UWB  effects  their  other  uses  of  the  spectrum,  in  a  timely  manner. 

 Delay,  even  when  advisable,  still  has  costs.  If  we  find  that  our  rules  are  too  restrictive  and  we  fail  to  correct  them  promptly,  the  price  may  be  that  the  United  States  loses  its  leadership  role  in  ultra-wideband. 
 The  technology  could  easily  move  overseas,  where,  I  wager,  would-  be  competitors  are  only  too  eager  to  get  a  step  ahead  of  the  USA.  Lets  be  cognizant,  too,  of  the  need  to  proceed  so  as  to  inflict 
 minimal  harm  on  U.  S.  commercial  interests.  Some  companies  may  be  seriously  inhibited  by  the  limitations  being  announced.  We  should  not  expect  that  they  can  afford  to  stand  patiently  by  while 
 testing  and  approval  proceeds  at  glacial  pace.  I  hope  that  all  of  us,  whether  in  government  or  the  private  sector,  will  approach  our  nations  deployment  of  ultra-  wideband  with  the  sense  of  urgency  that  it  so 
 clearly  merits. 
 Finally,  I  want  to  welcome  Ed  Thomas  to  the  FCC.  He  started  with  ultra-  wideband    a  trial  by  fire!  I  look  forward  to  working  with  you.  I  also  want  to  thank  Julie  Knapp  and  the  whole  OET  team  for 
 their  dedication  and  hard  work  on  this  item.  Lots  of  weekends  and  late  nights  went  into  this  Order.  Thank  you. 
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 SEPARATE  STATEMENT  OF  COMMISSIONER  KEVIN  J.  MARTIN 
 RE:  Revision  of  Part  15  of  the  Commissions  Rules  Regarding  Ultra-  Wideband  Transmission  Systems,  First  Report  and  Order  (ET  Docket  No.  98-  153). 
 Spectrum  management  decisions  are  always  complex  and  challenging.  In  an  environment  where  the  amount  of  unencumbered  spectrum  is  decreasing  while  demand  continues  to  grow,  it  is  even  more 
 critical  we  make  interference  and  sharing  decisions  that  do  not  waste  this  precious  natural  resource.  Inevitably,  we  will  depend  more  and  more  on  sharing  the  spectrum  currently  available  to  avoid  such 
 waste.  Sharing  decisions  are  made  particularly  difficult  in  the  context  of  the  fiefdom  mentality  that  seems  to  characterize  players  who  fervently  guard  their  spectrum  turf,  regardless  of  whether  additional 
 use  can  be  accommodated.  Unfortunately,  the  result  is  often  unrealized  potential  that  can  never  be  recaptured. 

 I  am  excited  that  ultrawideband  technology,  which  operates  at  powers  10,000  times  lower  than  PCS  handsets,  will  allow  us  to  take  sharing  to  new  levels,  and  help  avoid  such  waste.  These  sophisticated 
 applications  can  potentially  co-  exist  with  spectrum  users  in  any  frequency,  while  promising  a  host  of  exciting  military,  public  safety,  medical  and  consumer  uses.  Firefighters,  police  officers  and  emergency 
 personnel  can  make  use  of  this  technology  to  detect  and  image  objects  that  are  behind  walls,  buried  underground  or  even  inside  the  human  body.  Automotive  applications  such  as  collision  avoidance  and 
 improved  airbag  mechanisms  will  have  a  direct  consumer  safety  impact.  Consumers  also  stand  to  benefit  from  enhanced  laptops,  phones,  video  recorders,  and  personal  digital  assistants  that  can  wirelessly  send 
 and  receive  streams  of  digital  video,  audio  and  data. 
 Most  importantly,  ultrawideband  challenges  the  notion  that  use  of  particular  frequencies  or  bands  is  necessarily  mutually  exclusive.  In  defiance  of  our  traditional  allocation  paradigm  that  often  forces  us 
 to  pick  winners  and  losers  in  the  face  of  competing  demands,  this  technology  seems  to  allow  more  winners  all  around. 

 I  am  disappointed  that  we  did  not,  at  this  time,  adopt  more  flexible  limits  that  may  have  allowed  for  even  more  widespread  use  of  this  technology.  I  look  forward  to  re-  examining  the  technical 
 parameters  established  in  this  order  once  we  have  more  data  that  will  address  the  interference  concerns  expressed  by  NTIA. 

 I  am  optimistic  that  future  technological  developments  will  provide  the  Commission  with  more  such  opportunities  to  insist  on  increasingly  efficient  use  of  current  spectrum.  Ultimately,  the  amount  of 
 available  spectrum  and  our  ability  to  use  it  is  perhaps  limited  only  by  technology.  Today,  however,  we  must  act  rationally  to  make  the  best  choices  within  the  spectrum  constraints  that  face  us  now. 
118