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Before the
               Federal Communications Commission
                     Washington, D.C. 20554

In the Matter of                     )
                                     )
Revision of Part 15 of the Commission's Rules         )
Regarding Ultra-Wideband Transmission       )     ET Docket 98-153
Systems                             )
                                     

                 NOTICE OF PROPOSED RULE MAKING

Adopted:  May 10, 2000                  Released:  May 11, 2000

Comment date:  [insert date 90 days from publication in Federal Register]
Reply comment date:  [insert date 120 days from publication in Federal Register]

By the Commission:

                            SUMMARY
                                
1.     By this Notice of Proposed Rule Making ("Notice"), we propose to amend Part 15 of the
Commission's rules to pave the way for new types of products incorporating ultra-wideband ("UWB")
technology. UWB devices may have the capability to provide for significant benefits for public safety,
businesses and consumers. While comprehensive tests have not been completed, UWB devices appear to be
able to operate on spectrum already occupied by existing radio services without causing interference, which
would permit scarce spectrum resources to be used more efficiently. We are moving forward with this Notice
to begin the process of identifying potential rule changes and alternatives necessary for the deployment of
UWB technology. The proposals in this Notice are designed to ensure that existing and planned radio services,
particularly safety services, are adequately protected. UWB technology is relatively new.  Further testing and
analysis is needed before the risks of interference are completely understood.  Such testing is already being
planned by a number of organizations.  We will provide ample opportunity to complete these tests and ensure
that analyses of the test results are submitted in the record for public comment before adopting any final rules
in this proceeding.  We invite broad comment on this Notice so that the Commission may ultimately provide
for the introduction of this new and exciting technology.


                           BACKGROUND

2.     The Commission, on its own motion, issued a Notice of Inquiry ("NOI") in this proceeding to
investigate the possibility of permitting the operation of UWB devices on an unlicensed basis under Part 15
of the FCC rules. Part 15 of the Commission's regulations permits the operation of RF devices without a
license from the Commission or the need for frequency coordination.  The technical standards contained
in Part 15 are designed to ensure that there is a low probability that these devices will cause harmful
interference to other users of the radio spectrum.  Intentional radiators, i.e., transmitters, are permitted to
operate under a set of general emission limits or under provisions that allow higher emission levels in
certain frequency bands.  Intentional radiators generally are not permitted to operate in certain sensitive
or safety-related frequency bands, designated as restricted bands, or in the frequency bands allocated for
television ("TV") broadcasting.

3.     The NOI observed that recent advances have enabled the development of UWB technology for a
variety of applications.   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 the Internet.  UWB radio systems typically employ pulse modulation whereby extremely narrow pulses
are modulated and emitted to convey or receive information.  The emission bandwidths generally exceed one
gigahertz.  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, the resonant frequency
of which determines the center frequency of the radiated emission.  The bandwidth characteristics of the antenna
will act as a low-pass filter, further affecting the shape of the radiated signal.
 
4.     The NOI observed that 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 fundamental emission into restricted frequency bands or into the television ("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 narrowband systems and may be
inappropriate for, and pose unnecessary restrictions to, UWB technology, particularly impulse systems.  For
example, Part 15 measurement procedures require the application of a pulse desensitization correction factor. 
The application of this correction factor can cause UWB systems to exceed the peak emission limits currently
specified under the Part 15 rules. 

5.     The NOI requested comment on the potential applications for UWB devices and their technical
characteristics, such as frequency ranges of operation, bandwidths, power levels, and operating distances. 
In addition, the NOI requested comments concerning what regulatory treatment would be most appropriate
for UWB devices, including whether they should be regulated under Part 15 or some other rule part.  The
NOI asked how the Commission should define UWB devices.  Further, the NOI sought comments on
whether UWB devices should be prohibited from operating in the restricted frequency bands and TV
broadcast frequency bands or if there are certain restricted frequency bands where the Commission should
permit UWB operation.  Comments were sought concerning what emission limits and measurement
procedures would be appropriate for UWB devices.  The NOI invited comments on any other matters or issues
that may be pertinent to the operation of UWB systems.  In response to the NOI, 42 parties filed comments and
37 parties filed reply comments.  The list of the commenting parties is shown in Appendix B.

6.     In the NOI the Commission noted that three requests for waivers of the Part 15 rules were filed
to permit the operation of UWB systems.  U.S. Radar Inc. filed a Petition for Waiver to permit the
operation of a ground penetrating radar system that could be used to detect buried objects.  Time Domain
Corp. filed a Petition for Waiver to permit systems that would be used by public safety personnel for high
resolution imaging of persons and objects behind walls or under debris.  Zircon Corporation also filed a
Request for Waiver to permit radar systems that would be used by the construction industry to detect
objects hidden inside walls or other building materials. Because the waiver requests included frequency
bands allocated to the U.S. Government, they were coordinated closely with the National
Telecommunications and Information Administration (NTIA).  The three waiver requests were granted on
June 25, 1999 by the Chief of the Office of Engineering and Technology, based on a number of technical
and other conditions requested by NTIA to protect against interference to radio services.

                                DISCUSSION

7.     We have thoroughly reviewed all of the comments and reply comments filed in this proceeding. 
 Based on this review, we believe that UWB devices may offer significant benefits for public safety, businesses
and consumers, as discussed in detail below.  Further, we observe that most UWB devices cannot operate
under our current regulations.  Therefore, we tentatively conclude that the Commission's rules should be
amended to provide for UWB devices. At the same time, we recognize that any new rule provisions for UWB
devices must ensure that radio services are protected against interference.  Many of the comments suggested
that further testing and analysis is needed before the potential for interference is fully understood, particularly
potential interference to safety services such as the Global Positioning System (GPS).  We note that the NTIA,
the U.S. Department of Transportation, and other organizations are planning such tests. We plan to allow a
reasonable period of time for submittal of test results into the record in this proceeding and will provide an
opportunity for public comment on the test results before reaching any conclusions.  However, we believe it
is appropriate at this juncture to issue a Notice of Proposed Rule Making to begin the process of identifying
possible rule amendments and alternatives.   This Notice provides an important framework for considering the
various technical issues.  We invite broad comment on these issues.  

Applications and General Characteristics 

8.     We believe that UWB technology holds promise for a vast array of new or improved devices
that could have enormous benefits for public safety, consumers and businesses.  Further, we anticipate the
UWB technology could create new business opportunities for manufacturers, distributors and vendors that
will enhance competition and the economy. UWB technology may also enable increased use of scarce
spectrum resources by sharing frequencies with other services without causing interference.  It is important
that we find ways to encourage the development and deployment of technologies that may allow more
efficient use of the spectrum. We note that Section 7 of the Communications Act of 1934, as amended,
requires the Commission "to encourage the provision of new technologies and services to the public." 
Accordingly, we conclude that the Commission should develop reasonable regulations that will foster the
development of UWB technology while continuing to protect radio services against interference.

9.     The NOI invited comment on the potential applications and general technical characteristics for
UWB technology, noting that UWB systems appeared to fall into two categories: systems that use radar
techniques for precise measurements of distance, and detection or imaging of objects; and communications
systems that can be used for voice, data and control signals.  

     Radar Applications

10.    The comments described a wide assortment of existing and potential applications for UWB
technology that employ radar principles.  Several parties note that UWB technology has been in use for some
time for ground penetrating radar ("GPR") applications.  GPR devices are used for purposes such as:
determining the structural soundness of bridges, roadways, and airport runways; locating buried containers that
may contain hazardous wastes; determining the location of underground utilities, such as natural gas,
electricity, water and sewage lines, irrespective of the composition of the piping or conduit; geologic surveys;
archeological digs; and, law enforcement and forensic investigations.  The comments stated that UWB
technology is being developed for new types of imaging systems that would enable police, fire and rescue
personnel to locate persons hidden behind a wall or under debris in situations such as hostage rescues, fires,
collapsed buildings, or avalanches.  Imaging devices also could be used to improve the safety of persons in the
construction and home repair industries by allowing individuals to locate steel reinforcement bars (i.e., re-bar)
in concrete, or wall studs, electrical wiring and pipes hidden inside walls.  

11.    Numerous other applications for UWB technology using radar techniques were brought to our
attention.  Potential automotive uses include forward-looking and lane change collision avoidance systems,
backup warning systems, air bag proximity measurement for safe deployment, sensors that detect bumps in the
road and automatically adjust suspension systems, and fluid level detectors for radiator, oil and gas levels. 
Potential medical uses include the development of a mattress-installed breathing monitor to guard against
Sudden Infant Death Syndrome, and heart monitors that act like an electrocardiogram except that they measure
the heart's actual contractions instead of its electrical impulses.  Some potential home safety uses include
intrusion detection systems that are less susceptible to false alarms, and space heaters that turn themselves off
when a child comes nearby. Other interesting UWB applications include liquid level sensors for everything
from water conserving toilets to oil refinery tanks and the use of UWB technology to allow auto focus cameras
to calculate distances more accurately.

     Communications Applications
     
12.    Several parties noted that UWB devices can be used for a variety of communications applications
involving the transmission of very high data rates over short distances without suffering the effects of multi-
path interference.   Such devices could be used to wirelessly distribute services such as phone, cable, and
computer networking throughout a building or home.  UWB communications devices could also be utilized by
police, fire, and rescue personnel to provide covert secure communications devices.   Some parties believe that
UWB technology would be useful for outdoor wide area communication systems.

     General Characteristics

13.    The comments suggest that UWB devices will have a variety of technical characteristics
depending upon the intended application.  U.S. Radar Inc., Geophysical Survey Systems, Inc. (GSSI), and the
U.S. Geologic Survey indicate that GPRs operate with center frequencies of up to 3 GHz, and with bandwidths
of up to 2 to 3 times the center frequency. Lawrence Livermore National Laboratories (LLNL) expects that
UWB devices will operate with a center frequency anywhere between 20 MHz and 60 GHz, with bandwidths
ranging from 150 MHz to 30 GHz.  Multi Spectral Solutions, Inc. (MSSI) indicates that it has developed
systems for the U.S. Government operating in the bands 30   50 MHz, 225   400 MHz, 1.3   1.7 GHz, 2.2
 2.7 GHz, 5.4   5.9 GHz and 9.0   11.0 GHz using bandwidths from 20 MHz to 2 GHz.  Time Domain
provides a table of potential UWB applications and the frequency ranges in which they are likely to operate. 
In this table, Time Domain suggests that GPRs and long range military communications will tend to operate
at frequencies below 1 GHz; law enforcement and emergency motion and imaging devices, high performance
microphones, security fences, and other devices will operate in the 1   2 GHz region; and devices such as road
and runway inspection radars, law enforcement and emergency service mobile imagers, buried victim rescue,
RF Asset ID and tracking devices, collision avoidance sensors, etc. will operate in the 2   8 GHz region and
above.  Time Domain states that it has built a number of UWB radars and communications systems operating
below 2 GHz with bandwidths of up to 800 MHz.

14.    GSSI indicates that GPRs typically have no more than 10 mW average power and 10 W peak
power, but it has designed GPRs for the U.S. Government that use up to 200 mW average power and 1 kW
peak power.   ANRO Engineering, Inc., notes that it has designed intrusion sensors for protecting defined
perimeters on water and land with average powers of up to 1 mW and peak powers of up to 1 kW.   MSSI
also indicates that it has developed a variety of devices for the U.S. Government and the military with average
powers between 2 mW and 100 mW and peak powers ranging between 0.2 W and 16 W.  MSSI anticipates that
commercial UWB applications can be met with the same power levels given for spread spectrum and UNII
devices of 1 W transmitter output power with a 6 dBi antenna.

15.    The NOI also requested comment concerning the expected or desired operating distances for
unlicensed UWB devices. GSSI expects GPRs to operate at depths from one meter up to tens of meters. 
Some parties suggest that most UWB devices will typically have operating distances from 1 cm to 30 meters. 
LLNL expects low power devices to have operating distances of 5 cm, and up to 1000 meters for high power,
long range devices.

16.    We observe that UWB technology may have a variety of technical characteristics, depending
upon the intended application. We have considered the technical information provided in the comments as
the basis for developing proposed rule amendments and alternatives, as discussed further below.

Regulatory Treatment

17.    In the NOI, the Commission suggested that most UWB devices should be regulated on an
unlicensed basis under Part 15 of the rules.  However, the NOI requested comment on whether there are
certain types of UWB devices or applications that should be regulated on a licensed basis under some other
FCC rule part.  The Ultra-Wideband Working Group (UWBWG), Zircon Corp., Clifford Harter, TEM
Innovations, Time Domain Corp., Rosemount Measurements, and ANRO Engineering favor utilizing an
unlicensed regulatory approach under Part 15 of the rules.  The Wireless Information Networks Forum
(WINForum) believes that some form of licensing is appropriate for UWB devices that deliberately emit
energy in restricted frequency bands.  Oak Ridge National Laboratory, TEM Innovations, LLNL, and
Arthur D. Little, Inc. believe that some form of licensing should be provided for low volume, higher power
UWB device operations.  Zircon generally supports unlicensed operation for UWB devices that meet the
emissions limits for Class B digital devices.   Zircon argues that the Commission should also permit UWB
devices that meet the emissions limits for Class A digital devices to operate on an unlicensed basis under
Part 15, but these devices should be coordinated with NTIA and registered in a data base listing the users
and their locations.  Zircon asserts that individual licensing may be necessary for devices operating above
the Class A limits.  GSSI suggests that UWB devices that radiate less that 10 mW average power and 1
kW peak power should be unlicensed.

18.    Upon reviewing all the comments, we observe that most of the near-term applications for UWB
technology involve relatively low powers and short operating ranges.  Further, we note that most UWB
devices are intended to be mass marketed to businesses and consumers and that individual licensing of each
device would be impractical.  These characteristics are largely consistent with devices that operate on an
unlicensed basis under Part 15 of the rules.  Accordingly, we tentatively conclude that it is appropriate to
regulate under Part 15 of the rules low power UWB devices intended to be mass marketed to businesses and
consumers. 
     
19.    We request comment on our proposal to accommodate very low power UWB devices within
Part 15 of the FCC rules. We recognize that UWB technology may be developed for higher power
applications such as wide-area mobile radio services.  However, we find that such applications raise 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.  We observe that there is insufficient information in the record
to address such issues.  Accordingly, we are not making any proposals at this time to allow high power
UWB devices to operate under Part 15 or on a licensed basis.

UWB Definition

20.    In the NOI the Commission recognized that rules may need to be developed specifically for
UWB devices and invited comment as to an appropriate definition for UWB.  Several of the commenters
suggested that we adopt the UWB definition established by the OSD/DARPA  UWB radar review panel. 
That definition states that UWB devices must have a -20 dB fractional bandwidth of at least 0.25.  In order
for the fractional bandwidth to equal or exceed 0.25, the  20 dB bandwidth must be at least 25% of the center
frequency.  Under this formula, the minimum  20 dB bandwidth is 250 megahertz if the center frequency is 1
GHz, 1.25 gigahertz if the center frequency is 5 GHz, and 2.5 gigahertz if the center frequency is 10 GHz. 
Alternatively, M/A-Com suggests that a distinction between devices that operate above and below 10 GHz
is needed because at higher frequencies the benefits of UWB may be achieved with lower fractional
bandwidths.  M/A-Com believes that UWB should be defined as a fractional bandwidth of at least 25
percent for devices operating below 10 GHz and a bandwidth of at least 2.5 GHz for devices operating
above 10 GHz, based upon -20 dB.  Milltronics offers that we should allow UWB to comprise a pulse
transmission using a burst of controlled or stabilized carrier frequency where burst length is less than 3 nS
and the pulse repetition frequency ("PRF") is less than 5 MHz. Interval Research Corp. (Interval) believes
that UWB devices should be defined as any device having a fractional bandwidth greater than .25.  MSSI
suggests that, instead of defining the term UWB, we should define and apply the term "bandlimited short
impulse," or "bandlimited impulse," because UWB devices are better categorized by their duty cycle, or
excess bandwidth ratio, rather than by their fractional bandwidth. Rosemount Measurement believes that
any device that has a spectrum usage greater than 1.5 GHz should be considered UWB. Other
commenters made similar suggestions, but asked that we take antenna characteristics into account when
determining emission bandwidth. SAAB Marine Electronics asserts that a device using a fairly smooth
frequency spectrum with a bandwidth greater than 5 percent of the center frequency should be considered
UWB.

21.    We preliminarily believe that the definition established by the OSD/DARPA UWB radar
review panel is appropriate with some modifications.  Specifically, we are proposing to define UWB
devices as any device where the fractional bandwidth is greater than 0.25 or occupies 1.5 GHz or more of
spectrum.  This modified definition will avoid situations where devices operating at several gigahertz and
above might unnecessarily use wide bandwidths simply to qualify as an UWB device.  We are also
proposing to base the definition of an UWB device on the   10 dB bandwidth rather than the   20 dB
bandwidth.  We propose this modification because UWB devices will operate so close to the noise floor that
in many cases it will not be possible to measure the   20 dB bandwidth. For the purpose of this definition,
we will define the center frequency of the transmission as the average of the upper and lower  10 dB points,
i.e., (fH+fL)/2, as noted earlier.  Finally, we are proposing that the bandwidth be determined using the
antenna that is designed to be used with the UWB device.  We invite comment on this proposed definition
and 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. We request comment on
whether we should use some other method to determine the emission bandwidth, such as a calculated
bandwidth based on pulse width.  We also request comment on whether we should define UWB devices as
limited to devices that solely use pulsed emissions where the bandwidth is directly related to the narrow
pulse width. We recognize that other types of modulation, such as linear sweep FM, could be employed to
produce UWB equipment.  However, we do not believe that we have sufficient information to propose
limits and measurement procedures for such systems.  Until more experience is gained, we believe that our
initial rule making proposals should reflect a conservative approach. In addition, we request comment on
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.  Finally, we request comment on any alternative definitions that may be
appropriate.  

Frequency Bands of Operation

22.    In the NOI, the Commission noted that Part 15 designates certain sensitive and safety-related
frequency bands as restricted bands.  Only spurious emissions not exceeding the general emission limits
are permitted within these restricted bands or, with few exceptions, within the frequency bands allocated for
TV broadcasting.  Comments were requested on whether the Commission should eliminate the requirement
that only spurious emissions be permitted within the restricted bands and the TV broadcast bands. 
Comments were also requested on whether UWB operation should be permitted in certain restricted bands
and the impact that retaining certain restricted bands may have on the viability of UWB technology.

23.    Most of the commenting parties agree that the majority of UWB systems cannot avoid
transmitting within the restricted bands.  In some cases, particularly with GPRs, it is necessary that the
equipment operate in the restricted bands and TV broadcast bands below 2 GHz in order to obtain sufficient
ground penetration to detect or image objects.  A number of parties raised concerns that UWB devices
could cause harmful interference to existing radio operations in the restricted frequency bands, TV
broadcast bands, amateur radio frequency bands and others.  Several parties raised particular concerns
about potential interference to GPS operating in the frequency band 1559   1610 MHz.  The U.S. GPS
Industry Council argues that UWB operation should be limited to spectrum well above 1610 MHz,
preferably above 3 GHz, to protect GPS operations from harmful interference.  With regard to retaining
certain restricted bands, several comments opposed the use of filters to avoid operation within those
bands.  As stated by Time Domain, the addition of filters to notch out portions of the transmitted spectrum
would result in higher cost and would disperse the waveform over time due to complex ringing modes of
the filter tuned circuits.  Time Domain adds that the requirement to use notch filters would render UWB
infeasible by decreasing the signal to noise ratio, reducing available processing gain, decreasing ranging
and positioning capability and removing multipath immunity and jamming resistance.  MSSI argues that
UWB operations should be confined to frequencies above 2 GHz. Interval suggests that we initially allow
UWB operations only in the frequency band 2.9-4.99 GHz.

24.    We have considered a number of factors in addressing what frequency bands should be made
available for UWB devices.  First, we believe that it is vitally important that critical safety systems
operating in the restricted frequency bands, including GPS operations, are protected against interference.
Second, we believe that there are a broad variety of potential applications for UWB technology, each of
which has unique spectrum attributes and requirements.  Third, we note that the various regions of the
spectrum have different propagation characteristics.  As Arthur D. Little, Inc. points out, for example, an
UWB signal operating at the general emission limits in 47 C.F.R.  15.209 would fall below a victim
receiver's thermal noise at a distance of 40 meters at 500 MHz, and at a distance of 10 meters at 5 GHz. 

25.    We have developed a number of alternative proposals based on these considerations. We
observe 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.   GPRs can neither avoid
nor notch out the restricted frequency bands.  We believe the risk of interference from GPRs is negligible
because the overwhelming majority of their energy is directed into the ground where most of the energy is
absorbed.  Emissions in other directions can be easily shielded without affecting the operating
characteristics of the GPR. In addition, GPRs are expected to have a low proliferation and usually operate
at infrequent intervals. Thus, the interference potential of these devices should be low.  We also note that,
according to the comments, these devices have been used in limited numbers for quite some time for both
government and non-government applications without any known instances of harmful interference. 
Accordingly, we propose to allow GPRs to operate in any part of the spectrum, subject to the emissions
limits discussed below.   We propose to define a GPR as an UWB device that is designed to operate only
when in contact with, or in close proximity (i.e., 1 meter) to, the ground for the purpose of detecting or
obtaining the images of buried objects.  We also propose to require GPRs to include a switch or other
mechanism to ensure that operation occurs only when it is activated by an operator and the unit is aimed
directly down at the ground.  We invite comment on these proposals.

26.    The situation is less clear with regard to UWB devices that would be used to detect or obtain the
images of objects inside or behind walls or other surfaces.  In particular, it is unclear whether the same
arguments that apply to GPRs concerning penetration depth and resolution similarly apply to other imaging
devices.    In contrast to GPRs, where signals are aimed at the ground, through-wall imaging devices could
aim their energy in any direction.  While the wall could attenuate these signals, the amount of attenuation can
vary widely depending on the composition of the wall.  We note that such systems would be expected to have
a low proliferation and would be operated infrequently. One option would be to treat all imaging devices the
same way as GPRs.  Alternatively, we could restrict the operation of such devices below a certain frequency.
We invite comment on these alternatives and any other approaches that may be appropriate.  Comments also
are requested on what provisions are needed to ensure that these systems operate only when they are in
contact with a wall.   In addition, comments should address 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.  Comments also are requested
on whether through-wall imaging systems should be required to incorporate automatic power control
features that would reduce power levels to the minimum necessary to function based on the composition of
the surface and its absorption of RF energy.

27.    We observe that most other applications for UWB technology could operate in a variety of
regions of the spectrum.  To realize the full benefits of this technology, we believe that we should establish
as few restrictions as possible on the operating frequencies, except as necessary to protect existing services
against interference.  We believe that UWB devices can generally operate in the region of the spectrum
above approximately 2 GHz without causing harmful interference to other radio services.  The UWB signals
will quickly fall off below the background noise because of the high propagation losses at 2 GHz and above. 
Further, most radio services operating above 2 GHz use directional antennas that generally discriminate
against reception of undesired signals.  Accordingly, we are not proposing any restrictions on UWB devices
operating at frequencies above approximately 2 GHz.  We invite comment on this proposal.

28.    We have 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. We note that 41 of the 64 restricted frequency bands are at or below
2 GHz, not counting the TV broadcast bands.  We are particularly concerned about the impact of any
potential interference to the GPS band at 1559   1610 MHz.  We also would be concerned about
interference to any additional frequencies allocated to GPS, e.g., the planned L5 frequency in the 960-1215
MHz band.  As pointed out by many of the comments, GPS will be increasingly relied upon for air
navigation and safety, and is a cornerstone for improving the efficiency of the air traffic system.  We note
also that GPS 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, use of GPS is expanding for
use by businesses and consumers for all sorts of applications, such as for navigation by automobiles, boats
and other vehicles, surveying, hiking, and geologic measurements.  Therefore, any harmful interference to
GPS could have a serious detrimental impact on public safety, businesses and consumers.  We note, in
addition, that propagation losses are not as great below 2 GHz, and services in this region of the spectrum
tend to employ omni-directional antennas that do not discriminate against undesired signals.  These factors
tend to increase the risks of interference below 2 GHz. 

29.    In light of these factors, we have significant concerns 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. As explained earlier, we believe that it is vitally important to ensure that critical
safety systems, including GPS operations, are protected from harmful interference. We invite comments on
UWB operations, potential restrictions on operation for UWB below 2 GHz, and the impacts such
restrictions would have on any potential applications for UWB technology. We also invite comment as to
the precise frequency below which operations of UWB devices may need to be restricted.  For example,
should we restrict operations 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 some other
frequency?  What should be the limit of any restrictions?

30.    We also wish to consider a number of alternative approaches to expressly prohibiting operations
in the frequency bands below 2 GHz.  For example, we note that certain UWB applications may be feasible
using extremely low signal levels.  We invite comment as to whether and at what levels, if any, we should
permit operation in the restricted bands below 2 GHz for devices that can operate using extremely low signal
levels. While we recognize that UWB technology generally cannot completely notch out frequency bands that
are a subset of their operating frequencies, we invite comment as to the viability of establishing a general
emission limit for UWB devices below 2 GHz, and whether a very stringent limit, or notch, should be applied
to the GPS band. Comments are invited on these alternatives and any others that may be appropriate for
regulating the frequencies of operation of UWB devices.  Even though we are considering restricting the
operation of UWB devices from use below approximately 2 GHz, we will consider allowing access to this
spectrum provided that test results and detailed technical analyses are submitted demonstrating that there is no
risk of harmful interference to GPS, to other services operating in restricted frequency bands, or to TV
broadcasting.

Further Testing and Analyses

31.    As noted above, we understand that various parties are planning experimental programs to
study the interference potential of UWB devices.  NTIA is planning a study at its Institute for
Telecommunications Sciences in Colorado. The Department of Transportation has already contracted with
Stanford University for tests to examine potential interference to GPS receivers.  We also understand that
certain manufacturers of UWB devices and other interested parties are planning tests.   We welcome these
testing programs and believe that the information they yield will be important for developing emission
limits for UWB devices that will protect other radio services against interference.  Commission staff will
monitor the progress of these tests.  We would like to encourage all of the interested parties to work
together cooperatively so that this work can be completed in a timely and efficient manner.  We encourage
parties to submit the test results into the record in this proceeding by October 30, 2000.  At the appropriate
time, we will issue a public notice to provide an opportunity to provide comments and replies on the test
results and analyses.  

32.    We recognize that 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. Almost any transmitter will cause interference if it is too close
to a receiver. For example, in the case of personal computer emissions our goal has been to provide TV
broadcast receivers with a 45 dB signal-to-interference ratio within the grade A contour where the personal
computer is separated from the TV receiver by 10 meters with an 8 dB separating wall.  Thus, as parties
perform measurements and analyses of UWB devices we ask that they consider and provide information on
receiver susceptibility to UWB signals along with the spatial geometries assumed for the susceptibility
studies.

33.    There are several possible interference mechanisms for receivers.  We request that comments
discussing interference risk to a particular service identify the specific interference mechanisms they are
concerned about and provide the following information, if possible:  1) typical desired signal strengths at
receivers in that service; 2) receiver inherent noise level or noise figure; 3) typical antenna patterns for the
system and frequency response of the antenna for out-of-band signals indicating expected differential
antenna gain for UWB signal and desired signal if applicable; 4) typical front end bandwidths before the
first mixer in receivers; 5) typical dynamic range limits of receiver mixers   preferably third order intercept
points; 6) typical IF bandwidths; 7) required signal-to-interference ratios for reliable performance of the
system assuming interference is white gaussian noise and with others types of interference; 8) required
interference to noise ratio; and 9) minimum distance to an interference source that is not under the control
of the user.  While it is helpful to know the signal level of a particular UWB emission that causes
interference to a class of receivers, we would like to extrapolate measurements to a variety of UWB signals
so that the designers of UWB devices will have flexibility in their waveform design.  For example, some of
the parties filing comments on the NOI felt that emission limits should be based on the unintentional
emission limits for digital devices contained in Section 15.109 of our Rules, with a possible adjustment of
the quantitative limit.  Above 1 GHz, this rule limits average field strength emissions to 150 uV/m at a
distance of 10 meters measured over a bandwidth of 1 MHz.  We request experiments and comments of
whether this framework is an appropriate model for interference potential of UWB signals to other systems. 
For example, what types of systems are effectively modeled by such a protection criterion?   What types
of systems need a different type of protection criterion?

Emission Limits

34.    In order to control harmful interference from UWB devices, it is important that we establish
appropriate emission limits.  In the NOI, the Commission noted that 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 bandwidths were chosen to protect various classes of receivers from
interference.  Further, 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 were sought on the following questions:  1) Are the existing general
emission limits sufficient to protect other users, especially radio operations within the restricted bands, from
harmful interference or should different limits be applied to UWB systems; 2) Should standards be based
on spectral power density and should those standards be designed to ensure that the UWB emissions appear
to be background noise; 3) What is the potential for interference due to the cumulative impact of emissions
from multiple transmitters; 4) Should a limit on the total peak level apply to UWB devices; 5) Can
emissions below or above a certain frequency range be further filtered to reduce interference potential
without affecting UWB performance; 6) Are the existing limits on the amount of energy permitted to be
conducted back onto the AC power lines appropriate for UWB devices; 7) What operational restrictions, if
any, should be required to protect existing spectrum users; and 8) Is the use of UWB modulation
techniques necessary for certain types of communication systems and, if so, for what purposes?

35.    As noted above, several comments filed in response to the NOI suggested that the Commission
should adopt the same emissions limits for UWB devices as already exist for unintentional radiators, such
as digital devices.  Others argue that we should apply the general emissions limits for intentional radiators,
but disregard pulse desensitization when performing measurements, effectively allowing higher peak levels
than permitted under the current rules.  The radiated emissions limits below 1 GHz are based on
measurements with a quasi-peak detector, which 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 are also 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.  Based on the comments on the NOI, it appears that the peak
levels for UWB devices could be up to 60 dB higher than the average levels.  This difference is significant
because these 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 receiver's bandwidth.  However, if the PRF is less than the receiver's
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. We also note that 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.  Accordingly, we believe that special consideration is needed to
develop emissions limits for UWB devices.

36.    We tentatively conclude 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 we
regulate 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.   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 identical pulses are often applicable to GPRs and
through-wall imaging devices, it may 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 signal's
spectral lines in places within the GPS band where GPS receivers are less sensitive to interference.   We
request comment 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.

37.    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.  We seek comment on whether we 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.

38.    Average and quasi-peak emission levels.  Several commenting parties indicated that the general
emission limits contained in Part 15 appear to be sufficient to control potential interference problems,
noting that there has been no increase in interference complaints regarding Part 15 devices despite the
geometric increase in the number of these devices.  Some of the commenters stated that the interference
would be no greater than that caused by the many unintentional radiators currently operating under Part
15.  Interval and the UWBWG, among others, requested that the same levels applied to digital devices be
applied to UWB products, including the higher limits currently applied to Class A digital devices used in
non-residential environments.  On the other hand, some of the comments requested that UWB be
permitted to operate at power levels that would exceed the general emission limits.  For example, ANRO
Engineering, GSSI and Krohne request that an average power of 10 mW be permitted.  MA/COM requests
levels as high as 250 mV/m at 3 meters.  Most of the commenting parties agreed that output limits should
be based on spectral power density to reduce potential interference.  However, other commenting parties
expressed concern that operation at the general emission levels could result in harmful interference to GPS,
Federal Aviation Administration systems, and weather radars at airports.  The ARRL also expressed
concern about interference to amateur operations should emissions be permitted at the general limits,
requesting that additional experience with equipment operating under waivers is needed before rules are
developed.

39.    The Part 15 general emission limits have a long and successful history of controlling interference
to other radio operations.  However, we also recognize that 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.  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.  We remain committed to
protecting the authorized radio services from receiving harmful interference from Part 15 devices.  We are
especially concerned about protecting radio services used for safety-of-life applications, such as GPS, from
such interference.  Accordingly, we believe 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.  As discussed above, we also are proposing 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, we tentatively propose that
emissions that appear below approximately 2 GHz be attenuated by at least 12 dB below the general emission
limits.  We believe that this attenuation below the general emission levels will provide additional protection to
the congested spectrum below 2 GHz without affecting the viability of UWB operations.  Comments are
requested on whether such an attenuation level is necessary, or whether additional attenuation below 2 GHz is
possible or necessary.  We also seek comment 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 are 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.  Commenting parties should address any additional changes to the
technical standards or to the operational parameters of UWB transmitters that could be employed to facilitate
the operation of these products below 2 GHz.

40.    We do not agree with the assessment of some of the comments that characterize the emissions
from UWB systems as having the same potential for causing harmful interference as emissions from
unintentional radiators.  Unintentional radiators are permitted to radiate anywhere within the spectrum at the
general emission limits.  In most cases, unintentional radiators, as well as most conventional Part 15
transmitters, generate emissions on only a few narrow frequencies that approach the general limits; the other
emissions are well below these limits.  However, the emissions from UWB transmission systems are
considerably different from those of unintentional radiators and conventional Part 15 transmitters.  The high
peak to average ratio of emissions, the extremely narrow pulse widths, and the pulse repetition frequencies
employed by UWB devices serve to differentiate UWB products from other Part 15 devices.  In particular, the
emissions from UWB transmitters could be near the maximum permitted levels over several gigahertz of
spectrum. Because UWB devices produce a wider range of emissions approaching the maximum emission
levels, we also disagree with the comments that we should apply the Class A digital device emission limits to
UWB products used in non-residential environments.   Further, the difficulty in controlling the location of
UWB devices, as demonstrated with our past experience with computers, and the potential that UWB products
could have higher incidences of unshielded outdoor applications than digital devices could result in UWB
devices causing a greater amount of harmful interference to other radio operations than digital devices.  In
addition, we do not agree with the comments that emission levels should be based on measurements taken
outside of the building in which the equipment is located.  Building attenuation varies widely based on the
location of the equipment within the building and the composition of the building.  It would be necessary to
test UWB devices in every installation to ensure compliance with the standards; this presents an unreasonable
test condition for the Commission, the manufacturers and the product users.  Further, many of the proposed
UWB products would be mobile devices, and it hardly seems likely that these products would be operated only
within buildings.  We believe that the emission limits being proposed in this Notice are 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 may be considered.

41.    Peak emission limits.  Those parties wishing to manufacture UWB devices expressed concern that
establishing too low of a peak limit would preclude UWB devices that inherently have a high peak to average
ratio.  As indicated by WINForum, peak output does not directly impact 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.  On the other hand, the comments also expressed concern that the peak
emission levels produced by UWB devices could cause harmful interference.

42.    We believe that a limit on peak emissions is necessary to reduce the potential for UWB emitters
to cause harmful interference to radio operations above 1 GHz.  However, before we can propose a limit for
peak emissions we first must clarify what is meant by peak for UWB applications.  In the past, we have used
a variety of peak definitions for different types of Part 15 devices in order to match the interference potential
of the system being regulated to the necessary parameters.  For example, for unlicensed spread spectrum
systems we regulate the "maximum peak output power" while for unlicensed National Information
Infrastructure ("U-NII") devices we use a definition based on average peak power over the transmitting
interval.  For most Part 15 devices, peak emission levels are field strength levels measured with a spectrum
analyzer that is calibrated in terms of an RMS-equivalent voltage.  Thus, the peak level measured by a
spectrum analyzer results in an RMS value of the true peak.  For the purposes of regulating UWB emissions,
we propose two methods of measurement:  1) the peak level of the emission when measured over a bandwidth
of 50 MHz which we believe is comparable to the widest victim receiver that is likely to be encountered, and
2) the absolute peak output of the emission over its entire bandwidth.  Comments are 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.

43.    In the case of the first definition of peak level, i.e., the peak signal strength measured over a 50
MHz bandwidth, we propose to apply a 20 dB limit with respect to the maximum permitted average emission
level.  This limit is consistent with the limit currently contained in 47 C.F.R.  15.35(b).  We further propose
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.  We propose 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.  In addition, we propose that the absolute peak emission level not be permitted to
exceed the average limit by more than 60 dB. 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.  For
example, an UWB emission with a  10 dB bandwidth of one gigahertz would be permitted an absolute peak
emission level over the total bandwidth of the emission of 46 dB above the maximum permitted Part 15
average emission level.  Similarly, an UWB emission with a  10 dB bandwidth of 5 gigahertz or greater would
be permitted an absolute peak emission level over the total bandwidth of 60 dB above the maximum permitted
average emission level.

44.    We do not believe that allowing such a high absolute peak signal relative to the Part 15 average
limit will significantly increase the potential for harmful interference to other radio operations due to the wide
spreading of the transmitted energy that is being required.  We request comment as to whether the higher
absolute peak limit will cause increased interference problems, especially using the proposed measurement
procedures described below and with the limitations on frequency bands of operation described above. 
Comments are 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. Comments also are
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 reference 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.  We intend
to rely heavily on submitted test data in determining what peak emission standards should apply to UWB
products.

45.    AC power line conducted limits.  The commenters were in agreement that the existing AC power
line conducted limits are not a burden and should be applied to UWB devices. However, several potential
UWB manufacturers requested that a higher limit be permitted for UWB devices used in non-residential
environments, equivalent to the limits applied to Class A digital devices.  For the same reasons cited above
for the radiated emission levels, we do not agree that higher conducted limits should be permitted in non-
residential environments.  Besides the difficulty in controlling the location in which the product will be used,
as demonstrated with our past experience with computers, UWB devices could have a higher incidence of
outdoor applications with negligible shielding of emissions radiated from the AC power lines.  We believe that
the existing limit in 47 CFR Section 15.207 for controlling the amount of energy permitted to be conducted
onto the AC power lines is a reasonable starting point for establishing standards until additional experience can
be gained with this equipment.  We seek comment on this conclusion.
     
46.    Cumulative impact.  There was considerable variation among the comments regarding the
effect of cumulative emissions from multiple, co-located UWB devices.  Many parties indicated that a
proliferation of UWB devices would have a negligible impact on the background noise level.  Other
parties express concern that there would be a cumulative effect and that this could impact vulnerable GPS
and FAA radar systems.  In particular, we note that the Commission's Technology Advisory Council,
Spectrum Management Focus Group, reviewed analysis papers from four UWB technology firms, Time
Domain, Interval Research, XtremeSpectrum, and A. D. Little Corp., and concluded that there would be no
significant rise in the RF noise floor.  Rather, that noise floor would be set by the closest UWB
transmitters.

47.    Nevertheless, as discussed above we believe that further testing and analysis is desirable on this
issue.  The cumulative impact appears to be 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.  This leads us to believe 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, the cumulative impact of several UWB devices may 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?  Further, what is the relationship
between pulse repetition frequency and the cumulative impact of a number of UWB devices?  We look
forward to receiving comments and test data from various parties along with relevant input from the
Commission's Technical Advisory Council.

Measurement Procedures

48.    In the NOI, the Commission addressed several questions on the measurement procedures that
should be applied to UWB devices.  The NOI noted that the current measurement procedures specify the
frequency range over which measurements are to be made, as well as the measurement detector functions
and bandwidths to be employed.  It also noted that with conventional narrowband Part 15 transmitters the
peak level provides an indication of the interference potential of the device by measuring the total amount
of energy that may appear in the passband of a receiver.  Comments were requested on the following
questions:  1) Does the peak output level continue to be indicative of the interference potential of an UWB
system; 2) Is a pulse desensitization factor appropriate for measuring UWB emissions or should another
measurement procedure be employed; 3) Is the frequency of the fundamental emission readily discernible
and are the current measurement ranges appropriate for UWB devices; 4) Are the current measurement
detector functions and bandwidths appropriate for UWB devices or should these standards be modified; and
5)  Are there any other changes to the measurement procedures that should be applied to UWB devices?

49.    Under the existing rules, below 1 GHz the emission levels are measured with a CISPR quasi-
peak detector, and above 1 GHz emissions are based on average and peak measurements. The comments
offered several methods for measuring UWB emissions.  Some parties requested the use of a simple
procedure that employs a spectrum analyzer with resolution bandwidth (RBW) and video bandwidth
(VBW) settings of 1 MHz.  WINForum provided a detailed analysis of the different measurements that
are needed to characterize the interference potential of UWB emissions.  WINForum asserts that different
measurement bandwidths are necessary depending on the pulse repetition frequency of the UWB transmitter
and the bandwidth of the receiver being protected from interference.  We recognize that WINForum raises
a valid point.  However, we believe it is important to develop measurement procedures that are reasonably
simple and straightforward and can apply to a wide range of UWB devices.  We hope that the additional
testing of UWB devices that is expected to occur will provide valuable insight into the measurement
procedures that should be applied.  In the interim, the following paragraphs contain our tentative proposals. 

50.    Average and quasi-peak measurements. Below 1 GHz, we propose to require emissions to be
measured using a quasi-peak detector, which effectively provides a weighted average.  This approach is
identical to the approach used under our current Part 15 rules for intentional and unintentional radiators. 
We invite comment on this proposal.  Above 1 GHz, we propose to require average measurements to be made
with a 1 MHz resolution bandwidth ("RBW"), as we currently do for intentional and unintentional radiators.
We also propose 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.  We believe that this is a simple and effective way to make the measurement but will consider
alternative techniques that can be shown to give comparable or more accurate results.

51.    Peak measurements. Most of the comments objected to applying a pulse desensitization correction
factor (PDCF) to determine the total peak emission, stating that the PDCF has little meaning for an UWB
emitter that may spread its energy over several gigahertz of spectrum.  Magnetrol International states that
peak levels can not be measured with a spectrum analyzer and suggested, along with ANRO Engineering, the
use of a fast sampling oscilloscope or similar device to measure peak levels.  As GSSI correctly points out,
the PDCF was designed for use with pulse modulated sinusoidal carriers.  We agree with the comments that
the PDCF was not designed for the measurement of impulse systems due to the lack of a sufficient number of
zero crossings in the waveform.

52.    Based on these concerns, we now propose to measure the peak emission level of UWB signals
directly in the time domain.  The first proposed definition of peak output, i.e., peak level based on a
measurement bandwidth of 50 MHz, is an untraditional one in the electromagnetic compatibility ("EMC") area
and can not be measured with normal commercial EMC test equipment.  However, microwave receivers
designed for radar interception and analysis are available with such characteristics and have costs comparable
to normal EMC test equipment.  The IF output of a microwave receiver that uses a wide bandwidth, e.g., 50
MHz, can be analyzed using a conventional oscilloscope in order to measure the peak level of the waveform
in the time domain. We seek comments on the feasibility of this testing technique as well as its utility as a
model for the interference potential of peak UWB levels.

53.    Under the second definition of peak emission level, i.e., the total peak output, we believe that this
can be readily done with standard sampling oscilloscope techniques for UWB signals with evenly spaced
identical elements, such as radar signals.  For signals with modulation of their amplitude or spacing we believe
that sampling oscilloscope technology can be used to measure the peak signal.  We recognize that such
measurement technology is more expensive than the equipment normally used for equipment authorization
measurements, however such technology is typically used for the development of UWB systems.  We also
request comments on allowing peak measurements to be made with a spectrum analyzer using the PDCF,
provided the applicant can show that the measurement as corrected by the PDCF is the true peak for the
waveform being tested.  We recognize that the peak level measured with a spectrum analyzer is the RMS
peak and must be adjusted to obtain the true peak level.  We seek comment on the types of UWB signals, if
any, for which this latter measurement technique would be appropriate. Recognizing that the width of the
fundamental lobe would be affected by the measurement antenna bandpass characteristics, particularly with
impulse systems, comments also are sought on whether the PDCF employed in the latter measurements should
be calculated based on an effective pulse width, i.e., two divided by the bandwidth, in Hertz, of the emitted
fundamental lobe.

54.    For peak measurements of UWB signals, the antenna used in the measuring equipment could have
an effect on the measured value.  In particular, it is important that the receiving antenna system have no phase
dispersion over the bandwidth of the signal.  While this is easy to achieve for conventional signals whose
bandwidth is small compared to the frequency, not all antennas have this characteristic in the case where the
bandwidth is a significant fraction of the frequency.  For example, a log periodic antenna has a different phase
center at a different distance from the emitter for each frequency, which would result in phase dispersion for
UWB signals.  On the other hand, cavity-backed spiral antennas and horn antennas would be less vulnerable
to this phenomenon.  We seek comment on what type of measurement antennas are needed to make accurate
peak measurements and the least restrictive way we might specify this in our final rules.

55.    Frequency range of measurement.  The comments generally agreed that the existing ranges of
frequencies over which measurements are required are appropriate.  LLNL suggested basing the frequency
range of measurement on a function of the pulse rise time for an impulse system. For impulse systems, we
believe 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. 
Noting that the emission spectrum will change depending on the specific measurement procedures employed,
e.g., the use of average versus peak measurements, comments are requested on any specific measurement
procedures that should be employed to determine the center frequency.  For a carrier modulated system, we
believe 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, we are concerned 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 are 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, commenting parties should note that the lower frequency range of measurements would
continue to be determined by the lowest radio frequency generated in the device.  Comments are 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. 

Prohibition Against Class B, Damped Wave Emissions

56.    In the NOI, the Commission noted that the rules prohibit the use of Class B, damped wave
emissions.  This prohibition stems from a similar International Telecommunication Union regulation and is
a throwback to the days when spark gap transmitters were employed.  There is no longer a clear definition
of a Class B, damped wave emission.  In the NOI, the Commission questioned whether the prohibition
against damped wave emissions should apply to UWB systems or if the prohibition was relevant in light of the
relatively low power levels employed by UWB devices.

57.    Except for MSSI, all of the comments agreed that we should eliminate the prohibition against
Class B, damped wave emissions as this does not appear to be relevant at the power levels being proposed for
UWB transmissions.  We agree.  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.  Accordingly, we propose to eliminate this prohibition for
UWB transmitters, and seek further comment on this proposal.

Other Matters

58.    Several proponents of UWB devices have questioned whether such devices can operate under the
standards contained in 47 C.F.R.  15.217-15.255.  This would result in a transmitter that may have a
fundamental emission bandwidth greater than one gigahertz operating under the standards developed for a
narrowband signal, e.g., the 30 MHz available for radar systems operating at 5800 MHz under 47 C.F.R. 
15.245.  These requests were submitted in an attempt to permit the manufacturers to avail themselves of the
higher power levels permitted under these rule sections.  However, in this Notice we are proposing specific
regulations regarding the frequency of operation and emission levels that would apply to UWB devices.  We
believe that the existing rules should be amended to clarify that they do not apply to UWB devices. 
Accordingly, we propose 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 variations in temperature and supply voltage.  If a frequency stability is 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.

59.    We propose to require that the regulations proposed in this Notice become effective 60 days from
the date of publication of the Report and Order in this proceeding in the Federal Register. Comments are
requested on this proposed transition provision. 


                            PROCEDURAL MATTERS

60.    As required by Section 603 of the Regulatory Flexibility Act, 5 U.S.C.  603, the Commission has
prepared an Initial Regulatory Flexibility Analysis (IRFA) of the expected impact on small entities of the
proposals suggested in this document.  The IRFA is set forth in Appendix A.  Written public comments are
requested on the IRFA.  These comments must be filed in accordance with the same filing deadlines as
comments on the rest of the Notice of Proposed Rule Making ("Notice"), but they must have a separate and
distinct heading designating them as responses to the IRFA.  The Commission's Consumer Information
Bureau, Reference Information Center, SHALL SEND a copy of this Notice, including the IRFA, to the Chief
Counsel for Advocacy of the Small Business Administration in accordance with Section 603(a) of the
Regulatory Flexibility Act, 5 U.S.C.  603(a).

61.    This is a permit-but-disclose notice and comment rule making proceeding.  Ex parte presentations
are permitted, except during the Sunshine Agenda period, provided they are disclosed as provided in the
Commission's rules.  See generally 47 C.F.R.  1.1202, 1.1203, and 1.2306(a).

62.    Pursuant to Sections 1.415 and 1.419 of the Commission's Rules, 47 C.F.R.  1.415 and 1.419,
interested parties may file comments on or before [insert date 90 days from date of publication in the
Federal Register] and reply comments on or before [insert date 120 days from date of publication in the
Federal Register].  Comments may be filed using the Commission's Electronic Comment Filing System
(ECFS), http://www.fcc.gov/e-file/ecfs.html, or by filing paper copies.  See Electronic Filing of Documents in
Rulemaking Proceedings, 63 Fed. Reg. 23,121 (1998).

63.    Comments filed through the ECFS can be sent as an electronic file via the Internet to
http://www.fcc.gov/e-file/ecfs.html.  Generally, only one copy of an electronic submission must be filed.  If
multiple docket or rule making numbers appear in the caption of this proceeding, however, commenters must
transmit one electronic copy of the comments to each docket or rule making number referenced in the caption. 
In completing the transmittal screen, commenters should include their full name, Postal Service mailing
address, and the applicable docket or rule making number.  Parties may also submit an electronic comment by
Internet e-mail.  To get filing instructions for e-mail comments, commenters should send an e-mail to
ecfs@fcc.gov, and should including the following words in the body of the message, "get form <your e-mail
address."  A sample form and directions will be sent in reply.

64.    Parties who choose to file by paper must file an original and four copies of each filing.  If more
than one docket or rule making number appear in the caption of this proceeding, commenters must submit two
additional copies for each additional docket or rule making number.  All filings must be sent to the
Commission's Secretary, Magalie Roman Salas, Office of the Secretary, Federal Communications
Commission, 445 12th Street, S.W., TW-A325, Washington, D.C.  20554.  Comments and reply comments
will be available for public inspection during regular business hours in the FCC Reference Center of the
Federal Communications Commission, Room TW-A306, 445 12th Street, S.W., Washington, D.C.  20554.

65.    The proposed action is authorized under Sections 4(i), 301, 302, 303(e), 303(f), 303(r), 304 and
307 of the Communications Act of 1934, as amended, 47 USC Sections 154(i), 301, 302, 303(e), 303(f),
303(r), 304, and 307.

66.     To make cited sources more easily available to the readers, we are testing the use of hyperlinks
to some FCC documents that are cited in this document.  The World Wide Web addresses/URLs that we
give here were correct at the time this document was prepared but may change over time.  We do not have
dedicated staff to update these URLs, however, so readers may find some URLs to be out of date as time
progresses.  We also advise that the only definitive text of FCC documents is the one that is published in the
FCC Record.  In case of discrepancy between the electronic documents cited here and the FCC Record, the
version in the FCC Record is definitive.

67.    For further information regarding this Notice of Proposed Rule Making, contact John A. Reed,
Office of Engineering and Technology, (202) 418-2455.

               FEDERAL COMMUNICATIONS COMMISSION



                              Magalie Roman Salas
                              Secretary
                           APPENDIX A

Initial Regulatory Flexibility Analysis

       As required by Section 603 of the Regulatory Flexibility Act, the Commission has prepared an
Initial Regulatory Flexibility Analysis (IRFA) of the expected significant economic impact on small entities
by the policies and rules proposed in this Notice of Proposed Rule Making ("Notice").  Written public
comments are requested on the IRFA.  Comments must be identified as responses to the IRFA and must be
filed by the deadlines for comments on the Notice provided above.  The Commission shall send a copy of this
Notice, including the IRFA, to the Chief Counsel for Advocacy of the Small Business Administration in
accordance with paragraph 603(a) of the Regulatory Flexibility Act.

A.  Reason for Action.

     This rule making proposal is initiated to obtain comments regarding proposed changes to the
regulations for radio frequency devices that do not require a license to operate.  The Commission seeks to
determine if its standards should be amended to permit the operation of ultra-wideband transmission systems.

B.  Legal Basis.

     The proposed action is taken pursuant to Sections 4(i), 301, 302, 303(e), 303(f), 303(r), 304 and 307
of the Communications Act 10 1934, as amended, 47 U.S.C. Sections 154(i), 301, 302, 303(e), 303(f), 303(r),
304, and 307.

C.  Description and Estimate of the Number of Small Entities to Which the Proposed Rules Will
Apply.

       For the purposes of this Notice, the RFA defines a "small business" to be the same as a "small
business concern" under the Small Business Act, 15 U.S.C.  632, unless the Commission has developed one
or more definitions that are appropriate to its activities.  Under the Small Business Act, a "small business
concern" is one that:  (1) is independently owned and operated; (2) is not dominant in its field of operations;
and (3) meets any additional criteria established by the Small Business Administration (SBA).  SBA has
defined a small business for Standard Industrial Classification (SIC) category 4812 (Radiotelephone
Communications) to be small entities when they have fewer than 1500 employees.  Given this definition,
nearly all such companies are considered small.

D.  Description of Projected Reporting, Recordkeeping and Other Compliance Requirements.

     Part 15 transmitters are already required to be authorized under the Commission's certification
procedure as a prerequisite to marketing and importation.  The reporting and recordkeeping requirements
associated with these equipment authorizations would not be changed by the proposals contained in this
Notice.  These changes to the regulations would permit the introduction of an entirely new category of radio
transmitters.

E.  Significant Alternatives to Proposed Rules Which Minimize Significant Economic Impact on
Small Entities and Accomplish Stated Objectives.

       We do not expect that the rules proposed in this Notice of Proposed Rule Making will have a
significant negative impact on small businesses.

F.  Federal Rules that May Duplicate, Overlap, or Conflict with the Proposed Rule.

       None.
                           APPENDIX B
                       Commenting Parties

Parties filing comments:

1.  American Radio Relay League, Inc. (ARRL)
2.  ANRO Engineering, Inc.
3.  Arthur D. Little Inc. (ADL)
4.  Dwain K. Butler, U. S. Army Corps of Engineers
5.  Chesapeake Computer Consultants, Inc.
6.  Consumer Electronics Manufacturers Association (CEMA) and National Association of
Broadcasters (NAB) - joint filing
7.  Endress + Hauser GmbH & Co. (Endress Hauser)
8.  Geophysical Survey Systems, Inc. (GSSI)
  9. David R. Hughes, Principal Investigator, National Science Foundation Wireless Field Test
   Project (corrected copy)
10.  Interval Research Corporation (Interval)
11.  George L. Johnston
12.  Jeff Kramer
13.  Lawrence Livermore National Laboratory, U.S. Department of Energy (LLNL)
14.  Low Tech Designs, Inc. (LTD)
15.  M/A-Com
16.  Magnetrol International
17.  MALA GeoScience USA, Inc.
18.  Multispectral Solutions, Inc. (MSSI)
19.  NeoVac
20.  Gary R. Olhoeft
21.  Pulson Medical, Inc. (PMI)
22.  Quality Research
23.  Radar Solutions International
24.  Rosemount Measurement
25.  SAAB Marine Electronics
26.  SAT COM Consultants, Inc.
27.  Robert A. Scholtz
28.  Enrico M. Staderine
29.  Technos Inc.
30.  TEM Innovations
31.  Time Domain Corporation (Time Domain or TDC)
32.  TRW Electronics & Technology Division
33.  UltraPulse Communications, Inc. (UCI)  (2 comments)
34.  Ultra-Wideband Working Group (UWBWG)
  35.      U.S. Department of Transportation, Federal Aviation Administration
36.  U.S. Geological Survey
37.  U.S. GPS Industry Council (Council)
38.  U.S. Radar Inc.
39.  Kathryn Vestal
40.  Wireless Information Networks Forum (WINForum)
41.  XtremeSpectrum, Inc.
42.  Zircon Corporation (Zircon)

Parties filing reply comments:

1.  American Radio Relay League, Inc. (ARRL)
2.  Arthur D Little Inc. (ADL)
3.  Broadband Telecom Systems
4.  Janice Bradley, Director, Lewistown Public Library
5.  Frank Burns
6.  California Geophysical Group, Inc.
7.  Barbara Dean Clark
8.  Thomas N. Cokenias
9.  Community Technology Centers' Network
10.  ENSCO, Inc.
11.  Geo-Recovery Systems, Inc.
12.  E. Renee Gross, Sidney Public Library
13.  Clifford Harter
14.  David R. Hughes
15.  Interval Research Corporation (Interval)
16.  Robert W. Jacob
17.  Krohne, Inc.
18.  M/A-COM
19.  Milltronics
20.  Oak Ridge National Laboratory
21.  Jim Rezowalli
22.  Rosemount Inc.
23.  Saab Marine Electronics (Saab)
24.  Timothy J. Shepard
25.  Southwestern Bell Wireless, Inc.
26.  SPARTA, Inc., Simulation Technology Division
27.  Sub-Surface Informational Surveys, Inc.
28.  TEM Innovations (2 replies)
29.  Time Domain Corporation
30.  Kathryn Vestal
31.  XtremeSpectrum, Inc.
32.  Ultra-Wideband Working Group
  33.     U.S. GPS Industry Council, American Airlines, The General Aviation Manufacturers Association,
  Stanford University (The GPS Research Program) and United Airlines
34.  John A. Williams
35.  Bonnie Williamson, Havre-Hill County Library
36.  Zircon Corporation
37.  Brian Zisk