**Before the**

**Federal Communications Commission**

**Washington, D.C. 20554**

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| In the matter of                 | *  | ET Docket No. 98-153         |
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| Revision of Part 15 of the       | ** |                              |
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| Regarding Ultra-Wideband         | *) |                              |
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**SECOND REPORT AND ORDER AND SECOND MEMORANDUM OPINION AND ORDER**

**Adopted: December 15, 2004 Released: December 16, 2004**

By the Commission: Chairman Powell issuing a statement.

**TABLE OF CONTENTS**

[Paragraph]{.underline}

I. Introduction 1

II\. BACKGROUND [2](#background)

III\. Second report and order 8

A. Low PRF systems in the 3.1-10.6 GHz band 9

B. Non-UWB peak power emission limits in the 5925-7250 MHz and 16.2-17.7
GHz bands 16

C. Vehicular radar systems in the 22-29 GHz band 29

D. Clarification of existing non-UWB peak power emission limits 50

E. UWB definition 55

F. Other issues raised in the comments 58

IV\. Second memorandum opinion and order 59

A. Interference to PCS and Cellular 61

1\. Background 61

2\. Unlicensed Part 15 operation and 47 U.S.C. 301 64

3\. Harmful interference to cellular, PCS and E911 operations 79

4\. Rights of incumbent cellular and PCS licensees 86

B. Interference to C-Band Fixed Satellite Service 92

V. Administrative Provisions 100

VI\. CHANGES TO THE
REGULATIONS........................................................Appendix
A

VII\. PARTIES FILING COMMENTS AND REPLY COMMENTS TO THE FNPRM
.....Appendix B

# Introduction

1.  By this action, we are amending Part 15 of our rules to provide
    greater flexibility for the introduction of new wide-bandwidth
    devices and systems. These amendments respond to comments received
    in response to the *Memorandum Opinion and Order and Further Notice
    of Proposed Rule Making* in this proceeding.[^1] In the *FNPRM*
    portion we invited comment as to whether we should provide this
    flexibility by amending our rules for ultra-wideband (UWB) devices,
    or alternatively, by making changes to the general provisions for
    unlicensed devices. We have chosen the latter course. As stated
    previously, we are reluctant to change the existing UWB rules until
    we have more experience with UWB devices.[^2] We continue to believe
    that any major changes to the rules for existing UWB product
    categories at this early stage would be disruptive to current
    industry product development efforts. However, we are amending the
    Part 15 non-UWB regulations to better accommodate devices and
    systems that use wide bandwidths. Specifically, we are permitting
    the use of peak emission levels, similar to the levels applied to
    UWB devices, for wideband emissions in the 5925-7250 MHz, 16.2-17.7
    GHz and 23.12-29.0 GHz bands. This action will facilitate the
    introduction of some of the operating systems sought by the
    commenting parties, including radar systems that would be used to
    improve automotive safety and tracking systems that could be
    employed for personnel location, such as hospital patients and
    emergency rescue crew, as well as for such functions as inventory
    control. Limiting these devices to certain frequency bands will
    minimize the interference potential to critical authorized radio
    systems. We also are taking the opportunity provided by this order
    to address the petitions for reconsideration of the *First Report
    and Order* (*1^st^ R&O*) in this proceeding filed by Cingular, Inc.
    and by the Satellite Industry Association.[^3]

# BACKGROUND

2.  On February 14, 2002, the Commission adopted the *1^st^ R&*O in this
    proceeding, amending Part 15 of its rules to permit the marketing
    and the unlicensed operation of products incorporating UWB
    technology.[^4] UWB radio systems generally employ pulse modulation
    where extremely narrow (short) bursts of RF energy are modulated and
    emitted to convey information.[^5] The emission bandwidths from
    these systems are large and may often exceed one gigahertz.[^6] The
    frequency response characteristics of the UWB 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 images of objects buried under ground
    or behind surfaces. UWB devices can also be used for wireless
    communications and, in particular, for short-range high-speed data
    transmissions suitable for broadband access to networks.

3.  Several categories of UWB devices are permitted to be operated under
    the Part 15 regulations: imaging systems,[^7] vehicular radars and
    indoor and outdoor communication systems. Because of their wide
    operating bandwidths, UWB devices operate in frequency bands that
    are allocated both to U.S. Government and to non-government
    operations.[^8] In order to permit the operation of UWB devices, it
    was necessary to amend two standards in the former Part 15 rules:
    the prohibition against operation in the restricted frequency
    bands[^9] and the limitation on peak power.[^10] UWB devices must be
    permitted to operate in the restricted frequency bands in order to
    accommodate the extremely wide bandwidths employed by these
    devices.[^11]

4.  For non-UWB unlicensed devices, the regulations limit the total peak
    power produced by the unlicensed transmitter.[^12] It was determined
    that the total peak power for UWB devices was not relevant; it is
    the power into a victim receiver that is important.[^13] Thus, the
    Commission amended its rules to increase the peak power level
    measured in a 50 MHz band centered on the frequency at which the
    highest average emission level is produced by the UWB device.[^14]
    This change increased the allowable peak power and modified the peak
    measurement procedure.

5.  The authorization for UWB devices to operate in the restricted bands
    and the amendment to the peak power limit and peak measurement
    procedures raised concerns that harmful interference could be caused
    to critical safety systems. Several parties performed various
    analyses and tests to determine the interference potential from
    wideband sources.[^15] In response to these interference concerns,
    the Commission, in cooperation with NTIA and other U.S. Government
    agencies, implemented the current UWB standards along with various
    operational restrictions on UWB devices. For example, UWB devices
    used outdoors for non-imaging applications are limited to hand-held
    devices that engage in two-way communications using the 3.1‑10.6 GHz
    band.[^16] No outdoor fixed use of non-imaging UWB devices is
    permitted. These operational restrictions, in combination with
    conservative technical standards, were established to ensure that
    UWB devices can coexist with the authorized radio services without
    the risk of harmful interference while we gain additional experience
    with this technology.

6.  On February 13, 2003, the Commission adopted a *MO&O* and *FNPRM* in
    this proceeding. The *MO&O* portion of that action responded to
    fourteen petitions for reconsideration that were filed in response
    to the *1^st^ R&*O. Several changes to the UWB regulations were
    adopted to facilitate the operation of UWB devices used as
    through-wall imaging systems by law enforcement, emergency rescue
    and firefighter personnel in emergency situations or as ground
    penetrating radar ("GPR") systems. The regulations also were
    clarified regarding the coordination requirements for imaging
    systems and the limits on emissions produced by digital circuits
    associated with UWB operation. Two issues raised by the petitioners
    and denied in the *MO&O* were addressed in the *FNPRM*.
    Multispectral Solutions, Inc. ("MSSI") requested that the Commission
    not restrict UWB operations in the 3.1-10.6 GHz band to hand-held
    devices but instead permit the operation of any type of device,
    including radar systems, as long as the device operated with a low
    pulse repetition frequency ("PRF"); Siemens VDO Automotive AG
    ("Siemens VDO") requested that the Commission permit the emission
    bandwidths and emission levels of a frequency hopping 22-29 GHz
    vehicular radar system to be measured while the transmitter is
    actively hopping. To obtain further comments, the Commission
    proposed the changes sought by MSSI and Siemens VDO in the *FNPRM*
    portion. In addition, on its own motion the Commission proposed: 1)
    to amend its peak power limits for Part 15 transmitters that employ
    wide operating bandwidths but do not operate under the UWB
    regulations; and 2) to eliminate the UWB definition[^17] to permit
    any transmission system, regardless of its bandwidth, to operate
    under the UWB standards. In response to the *NPRM*, six parties
    filed comments, eight filed reply comments, and NTIA submitted a
    late-filed comment.[^18] Because of our desire to coordinate with
    NTIA any changes to the regulations that could impact spectrum
    allocated for U.S. Government operations, we are accepting NTIA's
    late filed comment. All comments filed in this proceeding were
    considered by the Commission in its decisions. A list of the
    commenting parties, along with the abbreviations used to identify
    them, is attached as Appendix B.

7.  Two parties filed petitions for reconsideration of the actions taken
    by the Commission in the *MO&O*. Cingular, Inc. ("Cingular") objects
    to the presence and level of emissions from UWB devices that may
    appear in the frequency bands allocated for the Cellular
    Radiotelephone Service ("cellular") and for the Personal
    Communications Services ("PCS"), claiming that the Commission can
    not legally permit the unlicensed operation of radio frequency
    ("RF") devices except as specifically authorized by Congress under
    47 U.S.C. 307(e). Cingular also believes that cellular and PCS
    licensees have exclusive use of the spectrum assigned to their
    respective operations and that any emissions from UWB devices
    undermine this exclusivity. The Satellite Industry Association
    ("SIA") argues that the UWB emission limits in the 3650-4200 MHz
    band used by C-band fixed satellite systems ("FSS") are excessive
    and will result in harmful interference. XSI filed comments in
    response to the Cingular petition and Cingular filed a reply
    comment.[^19] XSI also filed comments in response to the SIA
    petition, the Coalition of C-Band Constituents filed a letter
    supporting SIA's petition,[^20] and SIA filed a late reply comment
    along with a motion for an extension of the reply comment period.
    That motion is granted and SIA's reply comment is accepted.

# Second report and order

8.  In the *FNPRM* the Commission proposed four amendments to Part 15 of
    its regulations. These amendments addressed: 1) the operation of low
    PRF systems in the 3.1-10.6 GHz band; 2) the measurement procedures
    applied to frequency hopping vehicular radar systems operating in
    the 22‑29 GHz band; 3) the peak power limits applicable to
    wide-bandwidth, non-UWB Part 15 transmitters; and 4) the elimination
    of the UWB definition. These subjects are discussed below.

## Low PRF systems in the 3.1-10.6 GHz band

9.  Under the current regulations, UWB consumer devices, other than
    vehicular radar systems, are required to operate with their ‑10 dB
    bandwidth in the 3.1‑10.6 GHz band and are limited to hand-held
    systems and to indoor-only systems.[^21] In its petition for
    reconsideration of the *1^st^ R&O*, MSSI requested that UWB systems
    employing a low pulse repetition frequency (PRF) be permitted to
    operate in the 3.1 GHz to 10.6 GHz band for any type of
    application.[^22] MSSI argued that low PRF systems have less
    potential to cause interference than UWB devices operating at a high
    PRF. In the *FNPRM*, the Commission disagreed with MSSI that all low
    PRF systems have a low potential for causing interference, however,
    the Commission sought to develop a more complete record on this
    issue. In the *FNPRM*, the Commission specifically invited comment
    on whether to amend the rules to permit the operation of any UWB
    product under the UWB standards currently designated for hand-held
    devices[^23] as long as the PRF does not exceed 200 kHz and the
    equipment employs a pulsed or an impulse modulation.[^24] Comments
    were requested on whether a different PRF limit should be employed,
    if additional changes to the standards, including changes to the
    emission limits, are necessary to permit low-PRF outdoor
    applications, or if the expansion of outdoor UWB devices should be
    limited to include only low PRF vehicular radar systems. Specific
    technical analyses supporting the comments were requested.

10. [Comments]{.underline}. MSSI comments that the restrictions on
    operating applications were implemented because the Commission was
    led to believe that UWB equipment must operate within the restricted
    frequency bands.[^25] However, MSSI argues that it is practical to
    build UWB devices that can operate outside of the restricted bands,
    citing its indoor‑only certified UWB radar system operating at
    6.020-6.699 GHz and the non-restricted unlicensed availability of
    the 5.46-7.25 GHz band. MSSI is concerned that the restrictions
    placed on the use of UWB devices mean that its radar cannot be used
    in vehicles for collision avoidance and blind spot detection, nor
    can it be used onboard aircraft or ships. MSSI adds that it is not
    possible to certify its radar under the non-UWB regulations because
    the device would have to reduce its power to meet the peak power
    limit if the Commission were to apply a pulse desensitization
    correction factor ("PDCF").[^26] In its reply comments, MSSI
    supplies a copy of a DARPA study[^27] demonstrating that
    interference potential is in most cases determined by the average
    power of a UWB signal in the narrowest passband of a receiver and
    that UWB signals using very low PRFs are unlikely to cause
    interference to receivers of any kind.[^28] MSSI requests that the
    Commission not limit the type or application of low-PRF UWB devices
    employed in the 3.1-10.6 GHz band, specifically citing vehicular
    radars and tagging systems[^29] as examples of technologies that
    could operate in the 3.1‑10.6 GHz band as a result of this change.

11. SARA supports expanding the permitted UWB usage in the 3.1-10.6 GHz
    band under the emission standards for hand-held devices.[^30] Delphi
    also requests that the Commission amend the UWB rules to permit the
    operation of radar systems in the 3.1-10.6 GHz band and wants UWB
    transmitters employing any modulation type, including high PRF
    systems, to be permitted to operate outdoors in the 3.1-10.6 GHz
    band.[^31] Delphi adds that permitting certain waveforms while
    excluding others constitutes an arbitrary, impermissible distinction
    unsupported by the technical characteristics of the signal and
    provides an unfair bias towards certain manufacturers. SIA opposes
    such a change, believing that high peak levels would expose fixed
    satellite service (FSS) receivers to harmful interference.[^32] SIA
    opposes the elimination of a PDCF above 1 GHz and wants the PDCF to
    continue to be applied to UWB devices.[^33] XM and Sirius also
    object to an expansion of the potential UWB applications until the
    proponents provide information regarding the technical
    configurations of their systems along with an analysis demonstrating
    how interference to the Satellite Digital Audio Radio Service
    (SDARS) can be avoided.[^34] James Page states that the reason for a
    low PRF is to obtain a high peak level to achieve longer
    transmission ranges and that this results in larger noise increases
    to the licensed services.[^35] James Page adds that the DARPA study
    only considers defense systems.

12. NTIA states that the emission limits applicable to hand-held UWB
    devices are adequate to protect Government systems from interference
    independent of the PRF or the application of the device.[^36] NTIA
    adds that the modulation employed in these systems must be limited
    to impulse modulation or to high speed chipping rates with
    bandwidths that comply with the existing UWB requirements. NTIA
    further states that the Commission needs to retain its existing
    prohibition against fixed outdoor infrastructures and the use of UWB
    devices in toys.

13. [Discussion]{.underline}. The interference potential of UWB devices
    is controlled by several factors. Limits on the average and peak
    emission levels produced by the devices are only one method of
    controlling potential interference. The potential for interference
    also can be reduced by limiting the proliferation of products, the
    applications for which the device may be employed and the manner in
    which the devices may be operated. While we determined that the
    emission limits established for UWB operation are sufficient to
    prevent interference to the authorized services, we also believe
    that our introduction of UWB devices should be conservative to
    further ensure that no interference will occur, especially to
    critical radio services operating in the restricted bands, from what
    could be widely prolific devices. For that reason, the Commission,
    in cooperation with NTIA, limited outdoor UWB operation to hand-held
    communication systems, severely curtailing outdoor proliferation. We
    find no evidence in the comments to support changing our UWB
    standards at this time. We note that UWB devices for consumer
    applications have not yet been placed on the market and, thus, we
    still have not gained the desired experience with these devices that
    we believe is necessary before it would be appropriate to consider
    whether the standards should be relaxed.

14. As previously stated by the Commission, low PRF UWB systems can have
    a higher potential for causing interference than high PRF UWB
    systems. Operation with a low PRF results in closer frequency
    spacing of the spectral emission lines. This, in turn, increases the
    probability that emissions will appear within the bandwidth of a
    victim receiver. Further, as the PRF decreases, the peak to average
    ratio increases. For UWB systems employing a low PRF, the peak
    emission limit becomes the defining standard and the average
    emission level decreases below the limit specified in the
    regulations. Accordingly, UWB devices employing a low PRF are
    constrained in their output levels by the limit on peak emission
    levels, not by the limit on average emission levels.[^37] Further,
    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 or a continuous wave (CW) signal, the effect of which
    is proportional to the average power in the UWB signal within the
    receiver's bandwidth. However, if the PRF is much less than the
    receiver's bandwidth, the UWB signal may appear to the receiver as
    impulsive noise and the effect is proportional to the peak power of
    the UWB signal unless some type of signal processing is incorporated
    in the victim receiver. The examples provided by MSSI demonstrating
    no harmful interference from low PRF UWB devices rely solely on
    receivers incorporating signal processing techniques, such as GPS
    receivers, and may not be applicable to many types of receivers in
    use today. The DARPA study submitted by MSSI does indeed demonstrate
    that radio receivers used in defense applications are not sensitive
    to peak emissions from UWB devices that operate with a PRF that is
    no greater than one percent of the victim receiver bandwidth.[^38]
    However, this finding may not be generally applicable to all radio
    operations. As stated in the DARPA study, "error correction coding
    reduces the probability of interference even more. Receivers that
    respond to peak signals are more susceptible to interference from
    low PRF UWB devices, but even these can benefit from interference
    cancellation techniques." It is because of the incorporated signal
    processing that many systems are able to reject interference from
    low PRF emissions. Indeed, the analyses performed by NTIA regarding
    the susceptibility of Government systems to peak emission levels
    referenced possible mitigation effects from signal processing.[^39]

15. The existing UWB rules limit outdoor consumer products in the 3.1 to
    10.6 GHz range to hand-held devices that employ two-way
    communications.[^40] Typically, such products are expected to employ
    high PRFs in order to maximize data through-put. Consequently, these
    products generally would be constrained primarily by the average
    emission limit and would have peak emissions well below the peak
    limit. Also, the PRF used in the UWB hand-held devices generally
    would be greater than the bandwidth of the receivers used in the
    authorized radio services, resulting in any interference impact
    being proportional to the average power in the UWB signal. The same
    is not true for UWB systems employing a low PRF. No measurement or
    other data has been submitted which demonstrates that
    high-proliferation systems operating outdoors at the UWB levels
    could be added anywhere within the 3.1‑10.6 GHz without increased
    interference risks.[^41] While some receivers may not be susceptible
    to interference from UWB systems that employ very low PRFs, this is
    dependent on both the bandwidth of the victim receiver and the error
    correction techniques employed in that receiver. There is not
    sufficient information to state that UWB devices, simply because
    they operate below some specified PRF, can not be a source of
    harmful interference to all receivers over a broad part of the
    spectrum. Accordingly, we do not agree that the UWB regulations
    should be amended at this time to permit any type of low PRF device
    to operate anywhere in the 3.1-10.6 GHz band under the standards for
    hand-held UWB devices. We do, however, believe that some relief may
    be possible in a limited portion of this frequency band. It appears
    that the primary goal of MSSI, SARA and Delphi is for the Commission
    to permit wide bandwidth systems to operate outdoors at the peak
    power limit permitted under the UWB regulations. As indicated above,
    the Commission also proposed in the *FNPRM* to increase the peak
    limit for non-UWB devices. We believe that changes to the non-UWB
    peak power level, as discussed in the following paragraphs, will
    accommodate the equipment designs sought by MSSI, SARA and Delphi.

## Non-UWB peak power emission limits in the 5925-7250 MHz and 16.2-17.7 GHz bands

16. Unless otherwise specified, the emissions below 1000 MHz from Part
    15 unlicensed devices, other than UWB devices, are measured using a
    CISPR quasi-peak detector and all emission limits at 1000 MHz and
    higher are based on average measurements.[^42] When an average
    emission limit is specified, the rules also specify a limit on peak
    power that is 20 dB greater than the average limit.[^43] For Part 15
    devices other than UWB devices, the total peak output power of the
    transmission must be measured. In some cases, peak measurement by a
    spectrum analyzer requires the application of a pulse
    desensitization correction factor (PDCF) in order to compensate for
    the analyzer's inability to respond fast enough to measure the true
    peak for pulse widths narrower than the inverse of the resolution
    bandwidth. The level obtained from the spectrum analyzer measurement
    of the peak emission can be considerably increased by the addition
    of the PDCF to obtain the true peak emission level. This standard
    was implemented when Part 15 devices primarily employed narrowband
    emissions.

17. Throughout this proceeding, the Commission recognized that the peak
    emission limit specified in 47 C.F.R. § 15.35(b) was established
    based on the operation of narrowband transmission systems and may
    unfairly penalize some wideband operations, effectively prohibiting
    the operation of these devices.[^44] Indeed, the Commission noted
    that the existing limit on the total peak power level is not well
    suited to measure the operation of, or represent the interference
    potential of, transmitters that employ extremely wide bandwidths. It
    is for that reason that the UWB standards permit the peak power to
    be measured over a bandwidth of 50 MHz, rather than over the entire
    bandwidth of the transmission. As stated in the *1^st^ R&O*, the
    total peak power produced by the UWB device is not relevant to
    interference potential as there are no receivers employed in the
    authorized radio services that operate at the bandwidths used by UWB
    systems.[^45] The widest bandwidth that normally would be employed
    by victim radio receivers is about 50 MHz. Thus, the Commission
    expressed its belief that the current limit on peak emissions from
    Part 15 intentional radiators could be amended to reflect a limit
    similar to that adopted in the *1^st^ R&O* for UWB systems,
    eliminating the bias under the Part 15 regulations towards non-UWB
    wideband operations.

18. Under the UWB regulations, the EIRP limit on peak emissions is 0 dBm
    based on the use of a 50 MHz resolution bandwidth (RBW).[^46] To
    facilitate testing, the rules permit the application of a lower RBW,
    down to as low as 1 MHz, provided the peak limit is similarly
    reduced to the level 20 log (RBW/50) dBm EIRP, where RBW is the
    resolution bandwidth in megahertz.[^47] This peak limit applies to
    the 50 MHz bandwidth centered at the UWB highest radiated emission
    level. The Commission proposed to amend 47 C.F.R. § 15.35(b) to
    permit an equivalent peak limit for non-UWB wideband Part 15
    transmission systems.

19. For the peak emission measurement for wideband devices, the
    Commission proposed that the RBW may not exceed 10 percent of the
    -10 dB bandwidth of the emission. This proposal was based on the
    requirement that UWB emitters, which must employ a minimum -10 dB
    bandwidth of 500 MHz, have a peak limit based on a 50 MHz bandwidth,
    *i.e.*, they use a resolution bandwidth that is not greater than 10
    percent of the minimum -10 dB bandwidth. Comments were requested on
    this proposal. Comments also were requested on the alternative
    proposal presented by MSSI, namely the rules should be amended to
    permit devices operating above 1000 MHz under the Part 15 general
    emission standards in 47 C.F.R. § 15.209 to comply with a peak
    emission limit of 5000 uV/m at 3 meters based on a measurement using
    a peak detector, a 1 MHz resolution bandwidth and a video bandwidth
    of no less than 1 MHz.[^48] The Commission requested comments on any
    changes to the interference potential of wideband Part 15 devices
    that may occur as a result of these proposals and requested
    technical support for comments arguing interference concerns.

20. [Comments]{.underline}. Delphi and Siemens VDO support the proposed
    change to permit wideband non-UWB devices to operate under the same
    limit as applied to UWB devices, agreeing that the current rules
    unnecessarily constrain non-UWB devices, but request that the peak
    emission level be measured using an RBW as wide as the -10 dB
    bandwidth of the emission.[^49] Siemens VDO indicates that a peak
    limit based on a RBW that is 10 percent of the -10 dB bandwidth
    should apply only to the emissions in the restricted bands with the
    caveat that the total EIRP must be reduced by 20 log
    (50 MHz/instantaneously occupied bandwidth) dB.[^50] Siemens notes
    that some systems would have as much as a 6 dB measurement penalty
    on the peak level by basing the power limit on the 20 log (RBW/50)
    proposed by the Commission, but states that this error would be
    reduced below 0.5 dB if the RBW is based on the -10 dB bandwidth of
    the emission.[^51] Alternatively, Siemens VDO suggests that the
    Commission adopt a peak limit of -28 dBm/MHz. James Page states that
    peak signals can cause more interference in some systems and
    requests that all peak emissions be limited to -34 dBm/MHz.[^52]
    Delphi opposes as inappropriate the proposal from MSSI to employ a 1
    MHz bandwidth to measure peak power under current non-UWB rules,
    indicating that this change could allow extremely high peak
    emissions that are as much as 20 times greater for low PRF radars
    than what was contemplated by the Commission.[^53] NTIA requests
    that the optional peak limit be established as ‑34 dBm/MHz instead
    of the 20 log (RBW/50) dBm proposed in the *FNPRM*. NTIA supplies
    extensive analyses to demonstrate that the peak power limit should
    not be increased to 5000 uV/m/MHz, as requested by MSSI, unless the
    duty cycle of the Part 15 emitter is one percent or less than the
    bandwidth of the victim receiver.[^54] MSSI expresses an interest in
    manufacturing low power, unlicensed radar systems, tracking devices
    and other equipment in the 5460-7250 MHz band, citing its UWB radar
    imaging system that operates in the 6020‑6699 MHz band.[^55] Delphi
    expresses a similar interest in manufacturing high-PRF radar systems
    in the 5460‑7250 MHz band[^56] and also requests that a higher peak
    power level be applied to its vehicular Back-Up Aid radar system
    operating in the 16.2-17.7 GHz band.[^57] No objections were raised
    in the comments regarding operation within these frequency bands.

21. [Discussion]{.underline}. We continue to believe that the current
    rules unnecessarily discriminate against the use of wideband
    unlicensed systems. For example, a transmission system operating
    above 1000 MHz with more than a 1 GHz bandwidth and a white Gaussian
    noise energy distribution is subject to an average emission limit of
    ‑41.3 dBm/MHz which is equivalent to an average emission level of
    ‑11.3 dBm/GHz. However, the total peak power limit for this emission
    is only -21.3 dBm. Thus, the average signal in this 1 GHz bandwidth
    complies with the standards but is, by itself, already 10 dB greater
    than the limit on the total peak power from the device. As already
    demonstrated by the Commission, the total peak power of such a
    wideband system is not relevant to the interference potential of the
    device. Rather, it is the potential power in the bandwidth of the
    victim receiver that is relevant. Recognizing that the widest
    receiver bandwidths generally encountered are less than 50 MHz,[^58]
    we determine that this discrimination against wideband systems can
    be eliminated by amending the rules to specify the peak power from a
    wideband Part 15 device based on the power density in a 50 MHz
    bandwidth, as specified for UWB devices. However, we also recognize
    that allowing increased peak power levels could have an impact on
    some radio services. Further, we are concerned that allowing higher
    peak power levels could result in a significant increase in the
    number of consumer products along with a corresponding increase in
    interference potential. We conclude that some cautious constraints
    on the permitted frequency bands of operation and the standards for
    operation within those bands are necessary while we gain this
    experience.

22. As noted earlier, 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 or a CW signal, the effect of
    which is proportional to the average power in the UWB signal within
    the receiver's bandwidth. However, if the PRF is much less than the
    receiver's bandwidth, the UWB signal may appear to the receiver as
    impulsive noise and the effect is proportional to the peak power of
    the UWB signal. Further, interference effects can be mitigated if
    error correction techniques are incorporated in the victim receiver.
    As noted earlier, receivers that employ error encoding techniques
    have some immunity to peak power levels, responding instead to the
    average emission levels.[^59]

23. We conclude that higher peak emission levels can be permitted in the
    5925-7250 MHz band without a corresponding increase in the potential
    that harmful interference would be caused.[^60] The fixed,
    fixed-satellite, and mobile systems employed in this band likely
    incorporate a sufficient level of signal processing to reduce, if
    not eliminate, their vulnerability to increased peak emission
    levels,[^61] or it is expected that such authorized systems would
    generally be located in remote areas or with the receiving antennas
    situated in such a manner that they would not be routinely subject
    to emissions from nearby Part 15 devices. While the comments request
    that we also permit higher peak emission limits in the 5460‑5925 MHz
    band, we determine that it is not prudent to do so until we have
    gained more experience with the unlicensed devices that may be
    developed. Authorized services in the 5460‑5925 MHz band include the
    Amateur Radio Service and the Intelligent Transportation Systems,
    both of which could be operating in close proximity to, and
    susceptible to interference from, unlicensed devices.

24. We also conclude that higher peak emission levels can be permitted
    in the 16.2‑17.7 GHz band, as requested by Delphi. However, it is
    not clear that sufficient signal processing would be employed to
    negate the increase in peak emission levels to radiolocation and
    Earth Exploration Satellite Systems ("EESS") operating in this
    band.[^62] Thus, we determine that a more cautious approach should
    be employed. Limiting operation in the 16.2‑17.7 GHz band to
    vehicular back-up assistance radars that operate only when the
    vehicle is in reverse will significantly limit the proliferation of
    such devices which should ensure that harmful interference does not
    occur to the authorized radio services. In addition, potential
    equipment manufacturers should be forewarned that the 17.3‑17.7 GHz
    portion of the 16.2‑17.7 GHz band has been allocated in Region 2 and
    the United States for the Broadcast Satellite Service, effective
    April 1, 2007. Once this allocation becomes effective, there is a
    possibility that the 17.3-17.7 GHz band may become designated as a
    restricted band[^63] and that Part 15 fundamental emissions will be
    prohibited in this portion of the spectrum.

25. Based on the above, we are adopting a peak limit for the 5925-7250
    MHz and 16.2‑17.7 GHz bands that is equal to 20 log (RBW/50) dBm
    EIRP with RBW, the resolution bandwidth of the measurement
    instrument, being 1 to 50 MHz, as proposed in the *FNPRM*. This peak
    level is consistent with the peak limit applied to UWB operation. As
    with UWB devices, this peak limit would apply to the 50 MHz band
    centered at the frequency at which the highest average emission
    level occurs. We agree with the commenting parties that a RBW not
    wider than the -10 dB bandwidth of the emission should be permitted,
    instead of an RBW based on 10 percent of the -10 dB bandwidth as was
    proposed in the *FNPRM*. If frequency hopping or stepped frequency
    modulation is employed, the frequency hop or step function shall be
    disabled and the transmitter shall operate continuously on a
    fundamental frequency to measure the -10 dB bandwidth that is used
    to determine the maximum RBW that may be employed for the peak
    emission level.

26. We recognize that the above actions will increase the proliferation
    of unlicensed devices operating in the 5925-7250 MHz band. Thus, we
    conclude that a cautious approach to the emission standards is
    appropriate. As discussed above, we also conclude that a cautious
    approach is necessary for the emission standards adopted for
    vehicular back-up assistance radars operating in the 16.2‑17.7 GHz
    band. Operation currently is permitted within the 5925-7250 MHz and
    16.2-17.7 GHz bands at an emission level of -41.3 dBm/MHz based on a
    linear average.[^64] However, we note that the UWB technical
    standards, established based on several interference analyses,
    represent a cautious approach to preventing harmful
    interference.[^65] The UWB standards permit lower fundamental
    emissions and unwanted emissions than those currently permitted for
    non-UWB devices. Further, NTIA requests that unwanted emissions from
    transmitters operating in the 5925-7250 MHz be subject to the
    emission limits applicable to hand-held UWB devices and that
    unwanted emissions from transmitters operating in the 16.2‑17.7 GHz
    band be subject to the unwanted limits applicable to UWB vehicular
    radars.[^66] Accordingly, we are adopting the more stringent
    specifications requested by NTIA, requiring that emissions from
    unlicensed transmitters operating within these bands comply with the
    same average emission limit and measurement standards that were
    established for UWB communication systems.[^67] The level of the
    fundamental emission shall not exceed an EIRP emission limit of
    --41.3 dBm/MHz and emissions above 960 MHz shall be based on the RMS
    average signal level. Emissions below 960 MHz shall be subject to
    the Part 15 general emission limits. For equipment operating in the
    5925-7250 MHz band, emissions outside of this band and within the
    3.1-10.6 GHz band shall not exceed an EIRP of ‑51.3 dBm/MHz, and
    emissions outside of the 3.1-10.6 GHz band and above 960 MHz shall
    not exceed the limits applicable to handheld UWB devices.[^68] For
    transmitters operating in the 16.2-17.7 GHz band, emissions between
    960 MHz and 16.2 GHz shall not exceed the limits applicable to UWB
    vehicular radars; emissions above 17.7 GHz shall not exceed an EIRP
    of --61.3 dBm/MHz. As with UWB devices, emissions from digital
    circuitry will be subject to the Part 15 general emission
    limits[^69] or to the limits for digital devices,[^70] as
    appropriate, provided those emissions are not intended to be
    radiated from the antenna.

27. In keeping with our cautious approach, we are implementing several
    additional requirements to further protect the authorized radio
    services. First, we are requiring that the ‑10 dB bandwidth of the
    transmission be contained within the 5925-7250 MHz or the 16.2-17.7
    MHz band, as appropriate, under all conditions of modulation and
    effects from frequency stability. We recognize that the levels of
    the emissions generally will continue to decrease as displacement
    from these bands increases and that this decrease will further
    reduce the interference potential to other radio services.[^71]
    Second, we are requiring that the ‑10 dB bandwidth of the
    transmission be at least 50 MHz for systems operating in the
    5925‑7250 MHz band and at least 10 MHz for systems operating in the
    16.2-17.7 GHz band. If frequency hopping or stepped frequency
    modulation is employed, these minimum bandwidth limits shall be
    determined with the frequency hop or step function disabled and the
    transmitter operating continuously on a fundamental frequency. These
    minimum bandwidth standards should accommodate existing product
    designs and will assure that devices operating at the higher peak
    power limits are indeed wideband devices that could be penalized by
    the current Part 15 restriction on peak power levels.[^72] No
    provision is provided to permit transmitters employing swept
    frequency modulation to perform measurements with the sweep stopped;
    these devices must continue to comply with the standards following
    the provisions of 47 C.F.R. § 15.31(c).[^73] Third, as noted above
    we are restricting operation in the 16.2-17.7 GHz band to vehicular
    back-up assistance radars that only operate upon engagement of the
    vehicle in reverse. We also are restricting operation in the
    5925‑7250 MHz band to terrestrial and to maritime applications and,
    like UWB devices, are prohibiting the use of these devices onboard
    aircraft or satellites or for the operation of toys. Operation
    onboard aircraft or satellites would result in much greater signal
    propagation distances and an increased likelihood of alignment with
    the receiving antennas of the authorized services. The operation of
    toys under these provisions could cause a significant increase in
    the proliferation of devices along with a corresponding increase in
    interference potential. There are ample provisions elsewhere in the
    regulations that permit the operation of toys and we see no need to
    expand their operation to include this frequency band. While we do
    not believe that the power levels being permitted in the
    5925‑7250 MHz band are sufficient to permit the establishment of
    wide-area communication systems, we also want to ensure that such
    systems cannot develop until greater experience is gained with
    unlicensed operation in this band. To ensure that this does not
    occur, as requested by NTIA[^74] we are prohibiting the use of fixed
    outdoor infrastructures in the 5925‑7250 MHz band under the rules we
    are adopting herein with one exception: operation onboard a ship or
    within a terrestrial transportation vehicle shall not be considered
    a fixed infrastructure.[^75] This should be sufficient to prevent
    the establishment of wide area communication systems, yet will not
    prevent the use of these devices for vehicular radar and maritime
    applications, as desired by the commenting parties.

28. We do not agree with Siemens VDO that a 10 log ratio should be used
    to determine the applicable peak power level for unlicensed devices.
    While we agree that, under certain conditions, *e.g.*, noise-like
    signals, a 10 log ratio is appropriate for determining the peak
    power with changes in RBW, this is not always the case. Indeed, the
    study by NTIA concluded that peak power follows a 20 log
    relationship for pulse-like emissions.[^76] We recognize that NTIA's
    proposed peak limit of ‑34 dBm/MHz was based on the possible
    operation of non-UWB systems through the entire 3.1 -- 10.6 GHz
    band. We conclude that it is not necessary to adopt this more
    stringent limit, particularly given the limited frequency bands
    where we are allowing such operation. Further, as discussed
    throughout this proceeding, we are concerned with the level of the
    peak power that appears in the bandwidth of a victim receiver. Our
    intent is to ensure that the total peak power emitted over a 50 MHz
    bandwidth does not exceed an EIRP of 0 dBm, as we required for UWB
    devices. Because of the difficulty in measuring peak output levels
    based on a 50 MHz RBW, we permit the use of a lower RBW with proper
    adjustment of the peak limit. Because many systems attenuate the
    power measurement with reductions in the RBW based on a 20 log
    ratio, we apply this ratio to all cases, ensuring that the peak
    power over a 50 MHz bandwidth will never exceed 0 dBm. MSSI, Delphi
    and others are permitted to employ a wider RBW, up to 50 MHz or up
    to the --10 dB bandwidth of the emission or, for frequency hopping
    or stepped frequency systems, up to the --10 dB bandwidth of an
    individual hopping or stepped channel, whichever is less, to obtain
    a higher peak power level. It may be to their advantage to do so if
    a noise-like emission is employed. For pulse-like systems, the peak
    level being implemented is equivalent to -34 dBm/MHz, the level
    requested by NTIA and by James Page. For noise-like systems with a
    PRF less than 50 MHz, the relationship of peak power in a 50 MHz
    bandwidth to the RBW corresponds to 10 log (RBW/50) dBm and a peak
    power as high as ‑17 dBm/MHz could be achieved, depending on what
    value is used for RBW. We are not implementing the ‑28 dBm/MHz limit
    requested by Siemens VDO as this could, depending on the exact
    modulation characteristics, result in a peak level of up to +6 dBm
    in a 50 MHz bandwidth.

## Vehicular radar systems in the 22-29 GHz band

29. The UWB regulations permit the operation of vehicular radar systems
    in the 22-29 GHz band.[^77] UWB vehicular radar systems are required
    to operate with a minimum instantaneous bandwidth of 500 MHz and may
    employ any modulation technique that results in this minimum
    bandwidth.[^78] The Commission concluded that it was necessary to
    establish a minimum UWB bandwidth to prevent narrowband Part 15
    devices from operating in the restricted frequency bands, as is
    currently allowed for UWB devices.[^79] In the *1^st^ R&O*, the
    Commission specifically precluded the operation of swept frequency
    systems, stepped frequency systems, and frequency hopping systems
    under the UWB rules unless the transmissions comply with the minimum
    bandwidth requirement and the emission limits when measured with the
    sweep, step function or hopping sequence stopped.[^80] The
    Commission indicated that this was necessary as no measurement
    procedure had been established to permit the emission levels from
    such devices to be determined while the transmitter is sweeping,
    stepping or hopping. Further, the interference aspects had not been
    evaluated based on the different emission level results that would
    be obtained if measurements were taken with the sweep, step function
    or hopping active.[^81]

30. In its petition for reconsideration of the *1^st^ R&O*, Siemens VDO
    requested that we allow pulsed frequency hopping vehicular radars to
    be included under the definition of a UWB device under a plan that
    would permit such transmitters to occupy the minimum required
    bandwidth within any 10 millisecond period rather than at any
    instantaneous point in time.[^82] This change would require a
    reversal of the decision that frequency hopping systems must be
    measured with the frequency hop stopped.[^83] Siemens VDO also
    requested that the Commission revise its rules to permit emissions
    to be averaged over a 10 millisecond period, with the hopping
    sequence active, instead of over a one millisecond period.[^84]
    Siemens VDO argued that it must operate with a center frequency of
    24.125 GHz, necessitating operation in the 23.6-24.0 GHz restricted
    band, and that operation at a higher frequency would increase cost
    and hardware complexity.[^85] Siemens VDO added that the Earth
    Exploration Satellite Service (EESS) systems at 23.6-24.0 GHz were
    the only identified potential interference victims of UWB radar
    systems operating in the 22-29 GHz band and that these systems
    employ integration times which are too long to distinguish between
    pulsed and pulsed frequency hopping modulation types.[^86] Siemens
    VDO provided a technical analysis to support its request to permit
    measurements of emission levels averaged over a 10 millisecond
    period with the system hopping in frequency.

31. As detailed in the *MO&O*, the type of modulation requested by
    Siemens was not considered in the notice and comments leading to the
    adoption of the UWB regulations, and there was no opportunity for
    the public to comment on Siemens VDO's proposal.[^87] Accordingly,
    the Commission denied Siemens VDO's petition for reconsideration as
    being beyond the scope of the issues addressed in this proceeding.
    However, the Commission agreed that the type of operation sought by
    Siemens VDO merited consideration. Accordingly, the Commission
    indicated that it would address Siemens VDO's proposal in the
    *FNPRM* to obtain public comment. In addition, the Commission's
    Office of Engineering and Technology issued a waiver of the UWB
    rules to permit the operation of Siemens VDO's vehicular radar
    system under technical criteria different from those requested in
    its petition for reconsideration.[^88]

32. In the *FNPRM*, the Commission proposed to adopt Siemens VDO's
    proposal. The Commission stated that its primary concern was not
    that the Siemens VDO equipment does not comply with the definition
    of a UWB system. Rather, its concern was that the Siemens VDO radar
    system does not comply with the UWB standards using the measurement
    procedures currently employed for frequency hopping systems [^89]
    and the possible interference aspects of this type of operation. For
    example, a UWB vehicular radar system that complies with the
    existing regulations will place a low level emission on a frequency
    at any given time. However, the Siemens VDO system momentarily can
    place a much higher level emission on that frequency. The
    measurement procedure requested by Siemens VDO entails the emissions
    being measured in the investigated frequency band over a time period
    where the transmitter is both active and quiescent within that band,
    resulting in an additional time averaging being applied to the RMS
    average measurement. For that reason, the Commission indicated that
    a victim receiver with a fast transient response may be more
    susceptible to interference from the Siemens VDO system than from
    other UWB systems. On the other hand, Siemens VDO argued that EESS
    systems operating in the 23.6‑24.0 GHz band will not be able to tell
    the difference between a distributed number of frequency hopping
    systems operating under the standards it has requested and a
    similarly distributed number of wideband radars complying with
    existing vehicular radar standards. The Commission also noted that
    there is a potential impact on terrestrial users which may be
    exposed to relatively few, but nearby, vehicular radars as well as
    the impact to EESS operations. It requested comments on whether the
    higher instantaneous power delivered by a frequency hopping system
    would cause harmful interference to these systems.[^90]

33. The interference potential of a transmitter can vary significantly
    due to slight differences in modulation techniques or changes in the
    frequency of operation where the victim receivers may have different
    susceptibility characteristics. Because of this, the Commission
    indicated that the proposed changes to the rules to accommodate
    frequency hopping systems would apply only to vehicular radar
    systems operating in the 22-29 GHz band. Further, the Commission did
    not propose to change any of the emission limits currently applied
    to UWB vehicular radar systems. Rather, it proposed new measurement
    techniques to accommodate frequency hopping UWB vehicular radar
    systems. Specifically, it proposed to permit frequency hopping
    systems to operate under the provisions for UWB vehicular radar
    systems provided the minimum UWB bandwidth is achieved in no greater
    than 10 milliseconds and the transmitter complies with all other
    technical standards for UWB operation in the 22-29 GHz band.
    Compliance with the average emission limit would be based on
    measurements using a one megahertz resolution bandwidth (RBW), a
    video bandwidth equal to or greater than the RBW, an RMS detector
    function, and a maximum 10 millisecond averaging period. The peak
    measurement would be performed as currently specified in the rules
    using a peak hold detector applied over a sufficiently long period
    that the measured levels cease increasing. Comments were requested
    on these proposed measurement procedures. For example, should the
    peak measurement be performed with the hopping sequence stopped;
    should a different averaging time be employed; should the averaging
    time be based on the number of hops and the dwell time of the hops;
    and should a maximum time be specified within which all hopping
    channels must be used?

34. Comments also were sought on the measurement procedure to be used to
    demonstrate compliance with the UWB minimum bandwidth standard.[^91]
    Siemens VDO requested that the bandwidth be measured based on two
    procedures described in the appendix to its petition.[^92] Both of
    the procedures suggested by Siemens are performed with the frequency
    hopping system active. However, the Commission expressed its concern
    that those procedures may not indicate the actual bandwidth employed
    by the system and the corresponding distribution of RF energy,
    depending on various technical parameters of the actual hopping
    system, *e.g.*, the distribution of the hopping channels, the dwell
    times for the hops, the number of hopping channels, the separation
    of the channels, the bandwidth of a single hopping channel, the
    number of hops in a specified time period, etc. Thus, the Commission
    proposed to require that the bandwidth be determined by first
    measuring the -10 dB bandwidth of a single hopping channel based on
    use of a peak hold detector and a 1 MHz resolution bandwidth and
    multiplying this value by the number of non-overlapping hops that
    occur within a 10 millisecond period. Comments were requested on
    this proposed measurement procedure as well as the procedures
    described by the petitioner. Comments also were requested on any
    interference concerns that arise from this modulation type or its
    method of measurement. Comments were requested on: the adequacy of
    the measurement results for the purpose of quantifying the impact to
    systems that could receive interference from frequency hopping
    vehicular radar systems operating under the proposed rules; any
    limits that should be applied regarding the number of hopping
    channels; the maximum occupancy time permitted for a hopping channel
    during any full hopping sequence; the maximum time it takes to
    complete a full hopping sequence; and any other pertinent technical
    characteristics.

35. [Comments]{.underline}. In its comments, Siemens reiterates the
    opinion from its petition for reconsideration of the *1^st^ R&O*
    that its frequency hopping system poses no greater risk of harmful
    interference than UWB systems generated by pulsed emissions, stating
    that the power level and distribution of each discrete spectral line
    component within the passband of a victim receiver are identical for
    these different emitters.[^93] Siemens VDO argues that the
    Commission's statement that the frequency hopped emission levels
    were similar to time averaged emissions is unsupported, stating that
    the frequency hopping duty cycle acts as a "blanking" interval that
    occurs when the emission does not appear within the victim
    receiver's bandwidth.[^94] Siemens VDO states that this does not
    influence the RMS measurement adding that the distribution of
    individual emissions over the observation (or integration) time is
    not important as the main purpose of an RMS measurement is to
    compare the energy content of different wave forms in a given time
    period. Siemens VDO requests that frequency hopping vehicular radar
    systems be permitted in the 22-29 GHz band with measurements made
    with the hopping active and a 10 millisecond averaging period.[^95]
    Siemens VDO argues that a 10 millisecond averaging period is
    necessary to avoid measurement errors, stating that a 1 millisecond
    integration period is not long enough to permit an accurate RMS
    power measurement of pulsed frequency hopping systems that require a
    longer period to complete a hopping cycle and that too short an
    averaging time results in inaccurately high power readings. [^96]
    Siemens VDO agrees that a 1 millisecond period can be applied to
    emissions in the 23.6‑24.0 GHz band. It provides a comparison of the
    emission levels produced by a frequency hopped system to that of a
    non-hopped UWB system.[^97] Siemens VDO states that the emissions
    from its system will be limited by the peak emission standard
    because of the low duty cycle associated with the frequency hopping
    rate.[^98] Further, Siemens VDO believes that the aggregate power
    averaged over a large geographical area would make it impossible for
    an EESS sensor in the 23.6-24.0 GHz band to distinguish between
    emissions from a hopped system and a pulsed UWB system.[^99] Siemens
    also states that SARA commissioned an interference study by a third
    party, CETECOM ICT Services, which concluded that there is no
    increased interference to amateur or to police radar operation,
    assuming "real" road conditions.[^100] As in its earlier petition
    for reconsideration, Siemens VDO recommends measurement procedures
    for determining peak and average emission levels, noting that it
    does not matter if the peak measurement is made with the frequency
    hop active or stopped.[^101] However, Siemens VDO believes that it
    is necessary to make RMS measurements with the hop active to obtain
    accurate readings, citing NTIA's statement that the radiated
    emissions from a pulsed frequency hopping radar can be accurately
    measured in the frequency hopping mode.[^102] SARA supports the
    comments of Siemens VDO, indicating that a 10 millisecond averaging
    taken with the hopping sequence active is necessary to obtain an
    accurate reading.[^103]

36. CORF opposes permitting frequency hopping systems to operate in the
    22-29 GHz band, arguing that these devices are an interference
    threat to EESS remote sensing instruments.[^104] CORF indicates that
    the 22-24 GHz band is of particular concern, citing the allocation
    of the 23.6-24.0 GHz band to passive observations including EESS and
    radio astronomy as well as the EESS allocation at 22.21-22.5
    GHz.[^105] CORF argues that the averaging time of the emissions must
    be shorter than the integration time of the victim receivers, citing
    EESS integration times as low as 1.2 milliseconds and the
    possibility of shorter integration periods in future
    equipment.[^106] Because of possible future short integration
    periods, CORF requests that a 0.1 millisecond averaging period be
    applied.[^107] CORF states that a preferred method of measurement
    would be through the use of a fast response (0.1 millisecond or
    faster) power detector measurement with the signal entering the
    power detector head filtered to define the passband of
    interest.[^108] Northrop Grumman and Raytheon oppose allowing
    frequency hopping systems in the 23.6-24.0 GHz band absent strict
    limits to reduce the potential for interference.[^109] They support
    the measurement intervals and techniques suggested by CORF to
    prevent frequency hopping devices from momentarily emitting at much
    higher levels.[^110] Siemens VDO responds that it has already
    indicated its willingness to accept a one millisecond integration
    period in the 23.6-24.0 EESS band, a limit that is less than the
    integration time of any EESS receiver in existence.[^111] However,
    Siemens VDO also notes that as integration times decrease, so does
    the receiver's sensitivity to interference so that a receiver with a
    0.1 ms integration time will experience a decrease in sensitivity of
    5 dB.[^112] Siemens VDO adds that spatial integration due to the
    aggregate power from multiple emitters being averaged over a large
    geographic area results in a smoothing of individual pulses and
    makes it impossible for the sensor to distinguish individual
    modulation techniques.[^113] Finally, Siemens VDO states that it is
    not practical to use a fast response power detector, as proposed by
    CORF, as it is not aware of any such commercially available
    device.[^114]

37. In its comments, NTIA states that frequency hopping transmitters
    must not be permitted to operate in the 23.6-24.0 GHz restricted
    band.[^115] NTIA adds that frequency hopping transmitters are not
    UWB devices and are capable of avoiding operation in the restricted
    bands. NTIA also requested that the transmitters comply with the
    emission limits applicable to UWB devices along with an average RMS
    EIRP emission limit of -61.3 dBm/MHz for the 23.6-24.0 GHz band.
    NTIA states that its interference analysis applies only to EESS
    operations in the 23.6-24.0 GHz band and can not be applied to
    ground based receivers where a single frequency hopping transmitter
    would be dominant.[^116] For ground based receivers NTIA notes that
    the establishment of power limits in a narrow frequency range is a
    primary concern. NTIA also states that the emission characteristics
    of the frequency hopped pulsed emissions will vary with pulse width,
    pulse repetition frequency, frequency hopping bandwidth, frequency
    hopping pattern, number of frequency hopping channels, hopping
    channel frequency separation, and the time duration of the hopping
    sequence. However, NTIA does not provide any suggestions as to the
    values that should be established for these parameters.

38. [Discussion]{.underline}. The UWB regulations were implemented to
    permit systems that, because of their extremely wide bandwidths, are
    unable to avoid operation within the restricted bands. [^117] A UWB
    transmitter must operate with a fractional bandwidth of at least
    0.20 or a -10 dB emission bandwidth of at least 500 MHz.[^118] The
    Commission implemented this minimum bandwidth requirement
    recognizing that transmitters that operate with less bandwidth could
    do so without having to transmit in the restricted bands.[^119]

39. Systems that employ frequency hopping modulation are required to
    demonstrate compliance with the UWB bandwidth limit when measured
    with the frequency hopping stopped.[^120] Unlike conventional UWB
    devices, frequency hopping systems have greater flexibility in
    determining which frequency bands will be employed and which will
    not. As indicated above, a waiver was issued earlier to Siemens VDO
    to permit the introduction of its vehicular radar system. As a
    condition of that waiver, the Commission, in cooperation with NTIA,
    required that the ‑10 dB bandwidth of the system be located between
    24-29 GHz, avoiding all restricted bands. Siemens VDO agreed that
    its equipment can function in compliance with this condition. Thus,
    Siemens has already demonstrated that its equipment can be designed
    to function without having to operate within the restricted bands.
    We are unwilling at this time to classify as a UWB device a
    frequency hopping transmitter that emits relatively narrowband
    signals. We determine that changes to the UWB definition at this
    nascent stage in its development would be disruptive and could
    further delay the introduction of devices. Accordingly, we do not
    conclude that the Siemens VDO frequency hopping system should be
    classified as a UWB device. However, we continue to believe that the
    type of operation proposed by Siemens VDO merits authorization.
    Vehicular radar systems have the potential to enhance collision
    avoidance techniques and should be accommodated under the rules if
    this can be accomplished without increasing the potential for
    harmful interference to the authorized services. We believe that the
    Siemens VDO system can be accommodated as a non-UWB Part 15 device
    under the proposal in the *FNPRM* to allow the operation of wideband
    systems at the peak power level permitted for UWB operation.
    However, as requested by NTIA, this will not permit the fundamental
    emission from the Siemens VDO radar to operate in the restricted
    bands. Thus, the frequency band of operation that is being
    established for this vehicle radar system is 23.12-29.0 GHz,
    exclusive of the restricted band at 23.6-24.0 GHz.

40. *Emission standards*. Emission limits capable of preventing harmful
    interference to the authorized radio services were developed in the
    *1^st^ R&O* for the operation of UWB vehicular radar systems in the
    22-29 GHz band. We conclude that similar standards should continue
    to apply to wideband, but not necessarily UWB, vehicular radar
    systems operating in this band. Accordingly, we are implementing a
    fundamental EIRP RMS average emission limit of -41.3 dBm/MHz for
    such devices. We also are implementing our proposal for a peak limit
    of 20 log (RBW/50) dBm EIRP where RBW is the resolution bandwidth of
    the measuring instrument.[^121] RBW shall not be less than 1 MHz or
    greater than 50 MHz. In addition, RBW shall not be greater than the
    -10 dB bandwidth of the device under test, as supported by the
    comments. If frequency hopping or stepped frequency modulation is
    employed, the frequency hop or step function shall be disabled and
    the transmitter shall operate continuously on a fundamental
    frequency to measure the -10 dB bandwidth that is used to determine
    the maximum RBW that may be employed for the peak emission level.
    Further, we are requiring that the -10 dB bandwidth of the
    fundamental emission be contained within the 23.12-29 GHz band under
    all conditions of modulation and effects from frequency stability
    and that the frequency at which the highest level emission appears
    be greater than 24.075 GHz. As requested by NTIA, we will require
    that emissions outside of the operating band comply with the
    emission standards applicable to UWB vehicular radar systems.[^122]
    The limit applicable to the 22-23.12 GHz and to the 23.6-24.0 GHz
    bands shall be the same as that applied to UWB emissions below 22
    GHz, *i.e.*, an EIRP of -61.3 dBm/MHz.[^123] As with UWB devices,
    emissions from digital circuitry will be subject to the Part 15
    general emission limits[^124] or to the limits for digital
    devices,[^125] as appropriate. Emissions below 960 MHz will be
    subject to the Part 15 general emission limits.

41. As with operation in the 5925-7250 MHz and 16.2-17.7 GHz bands, we
    conclude that a minimum bandwidth should be required to ensure that
    systems operating under the higher peak limit are wideband systems
    that could be penalized by the current Part 15 restriction on peak
    power levels. Siemens VDO states that its system occupies a
    bandwidth that is greater than 10 MHz for a single hopping channel.
    We believe that this is a reasonably wide bandwidth. Based on this,
    we are implementing a requirement that the ‑10 dB channel bandwidth
    of a system operating in the 23.12‑29.0 GHz band under these new
    provisions be at least 10 MHz. If frequency hopping or stepped
    frequency modulation is employed, this 10 MHz minimum bandwidth
    limit shall be determined with the frequency hop or step function
    disabled and the transmitter operating continuously on a fundamental
    frequency. We determine that this limit is sufficient to provide
    protection to existing authorized services while permitting the
    implementation of the Siemens VDO and other possible vehicular radar
    systems. We also are retaining our current requirement that these
    vehicular radar systems be used only for ground‑based applications.

42. *Methods of measurement.* We agree with Siemens VDO that its
    frequency hopping vehicular radar system should be permitted under
    the Part 15 regulations based on measurements performed with the
    frequency hopping active. However, we also believe that we must be
    cautious in this approach due to the paucity of interference data.
    Siemens VDO and SARA cite a statement from NTIA that the emissions
    from a frequency hopping system can be accurately measured with the
    hop active. However, this statement means only that emission levels
    can be detected and measured on a repeatable basis; it can not be
    inferred that such measurements provide emission levels with
    comparable interference potential. As previously stated by the
    Commission, the interference aspects of frequency hopping systems
    have not been thoroughly evaluated based on the different results
    that would be obtained from measurements made with the hopping
    active.[^126] While NTIA performed an analysis demonstrating that
    there is no increased impact to EESS operations below 24 GHz, no
    information has been submitted in this proceeding regarding the
    impact frequency hopping emissions may have on any other radio
    service.[^127] As stated by NTIA, the establishment of power limits
    in a narrow frequency range is a primary concern for ground based
    receivers.[^128] Further, the emission characteristics of the
    frequency hopped pulsed emissions will vary with pulse width, pulse
    repetition frequency, frequency hopping bandwidth, frequency hopping
    pattern, number of frequency hopping channels, hopping channel
    frequency separation, and the time length of the hopping sequence.

43. We note that the instantaneous average emission levels of the
    hopping channels could be considerably higher than the levels
    permitted under our rules if measurements are made with the
    frequency hop active, as requested by Siemens VDO. Because the
    transmission hops to a different frequency range during the
    measurement, the time that the signal is not transmitted on a
    frequency is averaged with the time that the transmission occurs.
    This time averaging is in addition to the RMS average of the active
    signal.[^129] Further, any increase to the time over which signals
    are averaged, *e.g.*, from 1 millisecond to 10 milliseconds, would
    permit a greater number of hopping channels to be included within
    the averaging with a corresponding increase in the instantaneous
    emission levels.[^130] No information or interference evaluation has
    been provided to justify the use of an averaging period longer than
    the 1 millisecond already adopted for UWB operations. Accordingly,
    we do not agree with Siemens VDO that the averaging period should be
    extended from 1 millisecond to 10 milliseconds.

44. The interference aspects of a transmitter employing frequency
    hopping, stepped frequency modulation or gating are quite similar,
    as viewed by a receiver, in that both appear to the receiver to emit
    for a short period of time followed by a quiet period.[^131] Gating
    the transmitter on and off produces the same effect on the measured
    data as would hopping the transmitter to a frequency outside of the
    measurement range. If emissions are permitted to be measured with
    the gating active, no emissions would be produced on the frequency
    being measured during the time the transmitter is gated off and the
    measured emission level would be reduced just like what occurs when
    a frequency hopping transmitter is measured with the hopping active.
    Conversely, requiring the emissions to be measured with the system
    operating continuously and the gating disabled produces the same
    results as measuring a frequency hopping system with the hopping
    stopped, *i.e.*, the "instantaneous" emission levels are determined.
    Consequently, permitting the emissions from frequency hopping
    systems to be measured with the hopping active could give such
    systems a competitive advantage by permitting higher instantaneous
    average power levels than what are allowed for gated systems. Since
    hopped, stepped and gated systems have similar interference effects
    and we have concluded that hopped systems may be measured with the
    hopping active, we also are eliminating the requirement that gated
    or stepped systems be tested with the gating or step function turned
    off.[^132] We concur that stepped frequency, frequency hopped and
    gated systems can be permitted to operate under the same standards
    and measurement procedures. As with operation in the 5925-7250 MHz
    band, no provision is provided to permit transmitters employing
    swept frequency modulation to perform measurements with the sweep
    stopped; these devices must continue to comply with the standards
    following the provisions of 47 C.F.R. § 15.31(c).

45. We also recognize that the UWB regulations for operation in the
    22-29 GHz band require vehicular radar systems that employ gating to
    be measured with the transmitter gated on.[^133] The interference
    potential of a UWB gated system is similar to that of a wideband
    gated system. We see no reason that these similar systems should not
    be subject to the same measurement procedures. Thus, we are amending
    the UWB regulations to permit the emissions from gated vehicular
    radar systems to be measured with the gating active. However, as
    requested by NTIA we do not agree that similar provisions should be
    applied to UWB systems that employ frequency hopping, stepped
    frequency or similar modulation techniques. Provisions were made in
    the regulations to permit UWB vehicular radars to operate within the
    22.10-23.12 GHz and 23.6-24.0 GHz restricted bands because their
    extremely wide bandwidths combined with their operation centered
    near 24.125 GHz resulted in the transmitters not being able to avoid
    operation within those restricted bands. However, frequency hopping
    and frequency stepped transmitters have direct control over where
    they operate in the radio spectrum. Further, there is sufficient
    spectrum to support their operation in the 22-29 GHz band without
    having to operate within the restricted bands. Accordingly, these
    transmitters must continue to be measured with the frequency hop or
    step function disabled and with the transmitter operating in a
    continuous mode if they are authorized under the UWB
    regulations.[^134] However, any vehicular radar employing frequency
    hopping, stepped frequency or similar modulation methods may be
    authorized to operate in the 23.12-29 GHz band, exclusive of the
    23.6‑24.0 GHz band, with the emission levels determined based on the
    transmitter's normal operating mode, under the non-UWB provisions
    being adopted in this order.

46. One of the primary reasons for requiring frequency hopping systems
    to be measured with the hop stopped was to ensure that the emissions
    are detected by the spectrum analyzer during the time period that
    the analyzer swept the frequency. In its comments, NTIA proposed a
    measurement procedure to ensure that the signal is detected at the
    proper level. Under this procedure, the RMS average and peak
    emission measurements are to be repeated with the analyzer in the
    maximum hold mode until there is no significant increase, *i.e.*,
    less than 3 dB, in any of the maximum hold values. We concur with
    the use of these measurement procedures and are implementing them in
    our regulations. Additional measurement guidance is expected to be
    provided by our Laboratory in the near future.

47. *Operation in the restricted bands.* As noted earlier, NTIA argues
    that there is no basis for permitting non-UWB devices to operate in
    the restricted bands. We concur and are not amending our regulations
    to permit such operation. Instead, we are specifying a frequency
    band of operation from 23.12-29 GHz, except for the 23.6-24.0 GHz
    band. This is comparable to what was provided to Siemens in its
    earlier waiver.[^135]

48. *Additional modulation types.* Based on the above, we are
    establishing a new rule section under Subpart C of Part 15 that
    permits the operation of vehicular radar systems in the 23.12-29 GHz
    band, except for 23.6-24.0 GHz, under similar emission limits that
    are applicable to UWB vehicular radar systems. This action resolves
    the request from Siemens VDO to permit the operation of frequency
    hopping vehicular radar systems in the 22-29 GHz band. However, we
    note that Delphi also requests that our regulations accommodate in
    the 22-29 GHz band non‑hopping vehicular radar systems that employ a
    bandwidth less than the 500 MHz required for operation under the UWB
    standards.[^136] We see no reason that modulation types other than
    frequency hopping should be prohibited from operating under the same
    standards. Accordingly, we are amending the regulations to permit
    the operation of vehicular radar systems in the 23.12‑29 GHz band,
    except for 23.6-24.0 GHz, regardless of the type of modulation that
    is employed. As noted above, transmitters employing swept frequency
    modulation must continue to be measured with the frequency sweep
    stopped at the frequency of measurement. We believe that these
    changes to the rules are consistent with our earlier UWB decisions
    to remain conservative in our implementation of the technical
    standards while we gain additional experience with this technology.

49. *Disposition of the waiver previously granted to Siemens VDO.*
    Siemens VDO was granted a waiver on June 23, 2003, under delegated
    authority of the Chief, Office of Engineering and Technology. The
    standards associated with that waiver were implemented in
    cooperation with NTIA. Among other things, these standards reflect
    compliance with the emission limits applicable to UWB vehicular
    radar systems. Any device that was designed to comply with the
    provisions of the waiver also will comply with the standards being
    adopted in this proceeding. For this reason, the termination of the
    existing waiver will not have any impact on Siemens VDO.
    Accordingly, the waiver previously issued to Siemens VDO to permit
    the operation of its frequency hopping vehicular radar in the 24-29
    GHz band shall expire upon the effective date of these regulations.

## Clarification of existing non-UWB peak power emission limits

50. In its petition for reconsideration of the *1^st^ R&O*, MSSI
    requested that the peak emission measurements of its pulsed emission
    system operating under the non-UWB Part 15 regulations, *i.e.*,
    Subpart C of Part 15, be performed using a 1 MHz resolution
    bandwidth without the application of a pulse desensitization
    correction factor (PDCF).[^137] While the Commission denied MSSI's
    request in the *MO&O*, it agreed with MSSI that the existing rule
    should be clarified rather than continue to rely on the spectrum
    analyzer operating instructions to indicate when a PDCF must be
    applied. Accordingly, the Commission in the *FNPRM* proposed to
    clarify that the peak emission limit for non-UWB operation is based
    on the total peak energy radiated by the device and that a PDCF may
    be needed to obtain the actual total peak emission level.

51. [Comments/discussion]{.underline}. MSSI requests an interpretation
    of Section 15.35(b) of the Commission's rules that a PDCF does not
    apply above 1 GHz, stating that this would permit it to commercially
    deploy its wideband devices.[^138] As proposed in the *FNPRM*, we
    are amending Section 15.35(b) to clarify that the peak power
    requirement applies to the total peak power produced by the device
    and may necessitate the use of a PDCF. This clarification does not
    result in any changes to the current Part 15 standards.

52. The PDCF originally was designed for measuring the peak output level
    of pulsed radar transmissions. The PDCF is a technique used to
    determine the true pulse amplitude based on measurements taken from
    a spectrum analyzer. The analyzer is unable to respond fast enough
    and therefore does not use sufficient bandwidth to measure all of
    the energy in the pulsed signal. Thus, when pulse widths are
    narrower than the inverse of the resolution bandwidth employed by a
    spectrum analyzer in a peak emission measurement it is necessary to
    apply a PDCF to obtain the total peak emission level.[^139] The
    requirement to apply a PDCF was contained within the Commission's
    specified measurement procedure, ANSI C63.4.[^140]

53. The Commission amended its regulations to change the reference to
    ANSI C63.4-1992 to a more recent version, ANSI C63.4-2001.[^141] The
    Commission adopted this revision stating that ANSI C63.4-2001
    provides clarifications to the measurement procedure and to the
    configuration of the equipment under test but does not contain any
    significant changes. However, a subsequent examination of the 2001
    version of ANSI C63.4 reveals that the reference to HP Application
    Note 150-2, as contained in ANSI C63.4-1992, has been replaced with
    a reference to ANSI C63.22, a procedure that exists only in a draft
    format and does not appear to address PDCF. While this change in
    ANSI C63.4 has further obscured when a PDCF must be applied, it does
    not negate the need to apply a PDCF under certain measurement
    conditions. The requirement to employ a PDCF continues to be part of
    the operating instructions on the proper use of a spectrum analyzer.
    Our clarification to the regulations should eliminate any confusion
    on the need to apply a PDCF under certain modulation and measurement
    conditions.

54. We are denying the request from MSSI for an interpretation of
    Section 15.35(b) of the Commission's rules that a PDCF does not
    apply above 1 GHz. MSSI made a similar request for interpretation in
    its Petition for Reconsideration of the *1^st^ R&O*.[^142] However,
    the Commission was clear in the *MO&O* that a PDCF does apply to the
    measurement of peak emission levels from non-UWB devices.[^143] The
    existing requirement to apply a PDCF in determining the peak power
    associated with the measurement of narrow pulsed emissions was
    discussed throughout the UWB rule making proceeding.[^144] Further,
    the Commission has been clear that the measurement of a peak
    emission for a non-UWB device, as specified under Section 15.35(b),
    could require the use of a PDCF depending on the technical
    parameters of the pulsed emission. The requirement to apply a PDCF
    is irrespective of the frequency at which the measurement is
    performed.[^145] We agree with the statement submitted by MSSI from
    Synergent Technologies that a PDCF is not required to determine the
    potential interference effects of a wideband pulsed waveform[^146]
    but we do not agree to MSSI's characterization that this comment
    means HP Application Note 150-2 is not applicable.[^147] Synergent's
    statement means only that the total peak power of a UWB emission is
    not required to determine the potential interference, as previously
    recognized by the Commission; it is the level of the undesired power
    in the bandwidth employed by a victim receiver that is important.
    This is the reason that the Commission applied the UWB peak
    measurement only to a relatively narrow, 50 MHz wide portion of the
    UWB emission. Accordingly, we do not agree that the rules should be
    interpreted in the manner requested by MSSI. As proposed in the
    *FNPRM*, we are clarifying the rules by stipulating that the peak
    emission limit for non-UWB devices is based on the total peak energy
    radiated by the device, unless specifically stated otherwise, and
    that, depending on the characteristics of the signal, it may be
    necessary to apply a pulse desensitization correction factor to the
    peak measurement of a non-UWB emission.

## UWB definition

55. [UWB definition]{.underline}. In the *FNPRM*, the Commission
    indicated that it was sympathetic to the concerns expressed by MSSI,
    Siemens and others throughout this proceeding regarding the changes
    in operational standards for unlicensed devices that may apply
    simply due to the bandwidth of the transmission system. It added
    that the Commission's standards in Part 15 need to reflect emission
    limits that reduce the potential for causing harmful interference to
    authorized radio services. While the emission limits applied to UWB
    operations ensure a low probability of causing harmful interference,
    they also require that the transmissions occupy a minimum bandwidth
    of 500 MHz or a minimum fractional bandwidth of 0.20.[^148] The
    Commission indicated that this minimum bandwidth requirement could
    cause a manufacturer to design transmitters that occupy more
    bandwidth than is operationally necessary or transmitters that
    inject noise to increase the occupied bandwidth simply to permit
    operation under the UWB regulations. The Commission was concerned
    that such systems would place greater energy in frequency bands
    where operation is not necessary for the system to function. Thus,
    the Commission concluded that a minimum bandwidth standard could be
    counterproductive to reducing the potential for harmful interference
    and proposed to eliminate the definition of an ultra-wideband
    transmitter in 47 C.F.R. § 15.503(d).[^149] The Commission proposed
    to permit the operation of any transmission system, regardless of
    its bandwidth, as long as it complies with the standards for UWB
    operation set forth in Subpart F of 47 C.F.R. Part 15 and to base
    the resolution bandwidth used for the peak power measurement to 10
    percent of the -10 dB bandwidth of the emission. Comments were
    requested on these proposals as well as on any potential increase or
    decrease in interference potential to authorized radio services that
    could be caused. The commenters were requested to address the
    interference potential from narrowband systems operating under the
    UWB regulations. The comments also were asked to address whether
    additional standards, such as a spectral power density limit based
    on a bandwidth narrower than 1 MHz, are needed.

56. [Comments]{.underline}. Delphi, SARA and Siemens VDO support
    elimination of the minimum bandwidth requirements.[^150] Delphi
    states that the minimum bandwidth specification is an unnecessary
    constraint that hampers spectrum use without added interference
    protection and adds that some applications require a variable
    bandwidth. SARA and Siemens VDO support the bandwidth measurement
    procedures proposed by Siemens VDO if the minimum bandwidth is not
    eliminated. SIA believes that this change to the rules should be
    made only on a case-by-case basis stating that UWB is at an early
    stage of development and the technology is likely to change
    significantly.[^151] SIA expresses particular concern that
    eliminating the minimum bandwidth requirement will increase
    aggregate interference to FSS receivers. XSI opposes elimination of
    the UWB minimum bandwidth stating that this would increase the
    threat of interference without promoting flexibility.[^152] XSI
    notes that there is ample spectrum outside of the restricted bands
    to accommodate devices with less than the minimum UWB bandwidth. XSI
    believes that changing the rules at this time will result in
    increased uncertainty and confusion and will further delay
    commercial availability of UWB devices. NTIA opposes eliminating the
    bandwidth requirements, stating that the supporting comments offer
    no technical support and expressing concern that such a change would
    permit operation in the restricted bands regardless of the bandwidth
    of the unlicensed emission.[^153] NTIA adds that all of the
    interference analyses it performed were based on the use of
    wideband, impulsive emissions and did not address narrowband
    signals.

57. [Discussion]{.underline}. We have accommodated the narrowband
    operations sought by Delphi, SARA and Siemens VDO through our
    amendments to the peak power levels for unlicensed operation in the
    5925-7250 MHz, 16.2-17.7 GHz and 22.0-29.0 GHz bands while, at the
    same time, keeping any further expansion of equipment applications
    out of the sensitive restricted bands. Because of these changes, we
    see no necessity at this time to eliminate the UWB minimum bandwidth
    requirements. We agree with XSI that such changes could be
    disruptive and could further delay the introduction of UWB devices.
    Further, we continue to believe that any operation in the restricted
    bands should be subject to the additional technical standards and
    operational parameters specified in the UWB regulations.
    Accordingly, we see no reason to change the minimum bandwidth
    requirements for UWB devices until additional experience has been
    gained with this equipment.

## Other issues raised in the comments

58. Delphi, with support from SARA, requested that the Commission amend
    its rules to permit the operation of UWB devices above 10.6
    GHz.[^154] Northrop Grumman and Raytheon requested the Commission to
    "clarify" that the sale of UWB vehicular radars is limited to
    original equipment manufacturer installed units or to qualified
    dealer retrofits to other vehicles where the manufacturers can show
    that the standards, *e.g.*, the attenuation of emissions in the
    23.6-24.0 GHz band above the horizontal plane, are met, adding that
    under no circumstances should these devices be permitted for retail
    sale.[^155] These issues are effectively untimely requests for
    reconsideration of issues that were already addressed by the
    Commission in the *1^st^ R&O*. Accordingly, they are denied.

# Second memorandum opinion and order

59. In the *MO&O* and *FNPRM*, the Commission responded to fourteen
    petitions for reconsideration that were filed in response to the
    *1^st^ R&*O, including petitions from Cingular and SIA. In general,
    the Commission denied the petitions for reconsideration, adopting
    changes to its regulations only to facilitate the operation of UWB
    devices used as ground penetrating radar ("GPR") systems[^156] or as
    through-wall imaging systems operated by law enforcement, emergency
    rescue or firefighter personnel in emergency situations. The
    regulations also were clarified regarding the coordination
    requirements for imaging systems and the limits on emissions
    produced by digital circuits associated with UWB operation. No
    changes were made to the type of UWB devices permitted to operate
    under the regulations. The frequency bands within which UWB devices
    are constrained to operate were not changed except as follows: GPRs
    were allowed to operate on any frequency and through-wall imaging
    systems were permitted to operate with a center frequency between
    1990 MHz and 10,600 MHz. The emission limits applicable to UWB
    devices were not changed except as follows: the emissions from
    through-wall imaging systems were relaxed by 7 dB, to an RMS average
    limit of -46.3 dBm/MHz EIRP, within the band 960-1610 MHz and by 10
    dB, to an RMS average limit of ‑41.3 dBm/MHz EIRP, within the band
    1610-1990 MHz.

60. Petitions for reconsideration of the *MO&O* were filed by Cingular
    and by SIA.[^157] Cingular objects to the presence and level of
    emissions from UWB devices that may appear in the frequency bands
    allocated for the Cellular Radiotelephone Service ("cellular") and
    for the Personal Communications Services ("PCS"), claiming that the
    Commission can not legally permit the unlicensed operation of radio
    frequency ("RF") devices except as specifically authorized by
    Congress under 47 U.S.C. 307(e). Cingular also believes that
    cellular and PCS licensees have exclusive use of the spectrum and
    that any emissions from UWB devices undermine this exclusivity. SIA
    argues that the emission limits in the 3650-4200 MHz band used by
    C-band FSS stations are excessive and will result in harmful
    interference. XSI filed comments in response to the Cingular
    petition and Cingular filed a reply comment.[^158] XSI also filed
    comments in response to the SIA petition, the Coalition of C-Band
    Constituents filed a letter supporting SIA's petition,[^159] and SIA
    filed a late reply comment along with a motion for an extension of
    the reply comment period. That motion is granted and SIA's reply
    comment is accepted.

## Interference to PCS and Cellular

### Background

61. On June 17, 2002, Cingular filed a Petition for Reconsideration of
    the *1^st^ R&O*. In that petition, Cingular claimed that the
    cellular and PCS spectrum are exclusive bands; that there was no
    reasonable basis for the Commission to allow UWB operations when
    such operations were not permitted under the previous Part 15 rules;
    that the UWB decision was not based on an adequate analysis of the
    interference that would be posed to cellular and PCS operations;
    that the Commission rejected all evidence concerning the operating
    levels used by PCS systems; that the UWB emission limits would cause
    interference to CDMA PCS systems; that there was no evidence that
    the Commission considered signal levels used by TDMA or GSM systems;
    that UWB interference to PCS jeopardizes E‑911 operations; that
    lower emission limits are needed for indoor UWB devices to protect
    PCS operations; and that UWB imaging systems must provide
    site-by-site coordination with cellular and PCS licensees. The
    Commission rejected these claims in the *MO&O*.[^160]

62. On February 12, 2003 after the close of the filing window for
    petitions for reconsideration for the *R&O* and on the day before
    the Commission adopted the *MO&O*, Cingular filed a "Supplement to
    Petition for Reconsideration." In the supplement, it argued that
    Section 301 of Act precluded the widespread deployment and operation
    of UWB devices without a license. The Commission dismissed the
    filing for procedural violations of the rules.[^161]

63. On May 22, 2003, Cingular filed the instant Petition for
    Reconsideration ("petition") of the *MO&O* forwarding arguments that
    were raised in its past petition and filings. In the petition,
    Cingular requests reconsideration claiming that the Commission's
    rule making proceeding was deficient in three respects. First,
    Cingular reiterates its claim that the authorization of Part 15
    devices on an unlicensed basis violates Section 301 of the
    Communications Act of 1934, as amended (hereafter referred to as
    "the Act").[^162] Second, Cingular again raises its claim, as
    previously argued in its Petition for Reconsideration of the *1^st^
    R&O*,[^163] that the Commission's authorization of UWB devices was
    performed without an adequate record to demonstrate that harmful
    interference would not be caused to cellular, PCS and E911
    operations.[^164] Third, Cingular also repeats the claim forwarded
    in its Petition for Reconsideration of the *1^st^ R&O* that the
    rules adopted fail to adequately protect the rights of incumbent
    commercial mobile radio service ("CMRS") licensees, *i.e.*, cellular
    and PCS licensees, by undermining the exclusivity rights of the
    licensees, by failing to include these licensees in a coordination
    process with UWB operators, and by failing to lower the emission
    limits for indoor UWB devices.[^165]

### Unlicensed Part 15 operation and 47 U.S.C. 301

64. Cingular argues that the authorization of UWB devices on an
    unlicensed basis violates Section 301 of the Communications Act.
    Cingular notes that one of the central reasons for creating the
    Commission was Congress' intent to reduce interference among
    spectrum users, and that by enacting Section 301, Congress
    prohibited wireless transmissions without a license. In particular,
    Cingular asserts that Section 301 requires that any person who uses
    or operates "any apparatus for the transmission of energy or
    communications by signals by radio" must do so by virtue of a
    "license granted under the provisions of the Act."[^166] Cingular
    further argues that Congress established detailed procedures in the
    Act for obtaining a license and notes that the threshold requirement
    for obtaining a license, which is contained in Section 308(a),
    requires the submission of an application.[^167] Acknowledging that
    the Commission first established rules for unlicensed devices in
    1938, Cingular points out that the Commission allowed unlicensed
    operations because it believed that the statutory requirement for
    licensing only applied to interstate operations, *i.e*., radiation
    from operating certain devices would be kept to low limits and would
    not cause interference to interstate communications which would
    otherwise bring such operations within the licensing requirement of
    Section 301.[^168] Cingular notes that Congress amended Section 301
    in 1982 to clarify that the Commission's authority applies to
    intrastate and interstate communications, and thus Cingular argues
    the Commission lost its purported basis for allowing certain devices
    to operate without a license.

65. Cingular also argues that Section 301, as well as several other
    relevant provisions of the Act discussed below, are not ambiguous
    and that the Commission is not entitled to deference in construing
    their terms. In opposition to XSI's assertion that unlicensed
    operations are authorized under Section 302(a) of the Act, Cingular
    argues that Section 302(a) was enacted in 1968 to give the
    Commission authority to prohibit the manufacture of equipment that
    is capable of causing interference but does not contravene the
    Commission's authority under Section 301 to authorize the operation
    of equipment.[^169] Cingular further rebuts XSI's assertion
    regarding Section 302(a) by noting that Congress has directed that
    only four services may operate without site-specific licenses
    pursuant to Section 307(e) of the Act,[^170]and that to accept XSI's
    assertion regarding Section 302(a) would render Section 307(e)
    meaningless.[^171] Also, Cingular rejects XSI's argument that
    Congress was aware of unlicensed operations and tacitly accepted
    them when it enacted Section 302(a) and took other legislative
    actions,[^172] arguing that the "doctrine of legislative
    acquiescence" is only an auxiliary tool that is used in interpreting
    ambiguous statutory provisions and that Section 302(a) was added to
    the Act approximately 30 years after the Commission first adopted
    rules for unlicensed operations. Likewise, Cingular rejects XSI's
    attempts to rely on subsequent legislative history to infer
    Congressional intent regarding Section 302(a), arguing that there is
    no need to resort to legislative history when a statute is clear.
    Thus, Cingular rejects XSI's assertion that the Commission is
    entitled to deference in construing its authority under Section
    302(a) and that the Commission can "fill in the gaps" of a
    statute.[^173]

66. We observe at the outset that the legal arguments Cingular raises
    here with respect to decisions in the R&O were addressed by the M&O
    and properly dismissed due to three clear procedural
    violations.[^174] Given the last minute attempt by Cingular to
    interject the legal arguments into the reconsideration of the R&O
    (the pleading was filed the day before the Commission adopted the
    M&O) it hardly appears that the procedural violations were
    inadvertent, but rather were intended to perhaps deprive the
    Commission of adequate time to consider them, possibly giving
    Cingular an advantage in any appeal.[^175] This circumstance
    provides added support for our decision that Cingular's repetitious
    legal arguments need not be considered under the Commission's
    rules.[^176]

67. Nonetheless, we address here the substance of Cingular's arguments
    in order to underscore the lawfulness of the actions taken in this
    docket and the reasonableness of the regulatory approach the
    Commission has devised to meet its statutory obligations to control
    the use of spectrum. We conclude that the language of Section 301 of
    the Communications Act does not mandate the type of licensing that
    Cingular suggests is required. Cingular's reading of the statute,
    moreover, ignores the practical realities that inform any reasonable
    reading of the statute and the nearly 70 years of "unlicensed"
    operations authorized by the Commission under Part 15. Congress is
    entirely familiar with this regulatory structure and for many years
    has indicated its acceptance of the Commission's approach.[^177]

68. Cingular's reading would require the Commission to apply Section
    301's licensing requirement to any apparatus that transmits any
    amount of energy, no matter how negligible.[^178] The statute does
    not compel that interpretation. Although Congress referred to "any
    apparatus," the statute is not phrased in terms of "any" energy,
    "any degree" of energy, or "any level" of energy. If we read such
    limiting language into the statute, the Commission would be required
    to individually license all devices that are designed to transmit
    any amount of energy for any purpose, with or without effect on the
    use of the spectrum for communications purposes. As discussed in
    greater detail below, such a result would lead to irrational results
    and stand at odds with Congress's recognition and tacit acceptance
    over the years of the Commission's Part 15 "unlicensed" regime. A
    more reasonable reading of Section 301, consistent with Congress's
    intent and subsequent legislation, would limit the licensing
    requirement to any apparatus that transmits enough energy to have a
    significant potential for causing harmful interference. Under our
    reading of the statute, the UWB transmission systems -- because of
    their operating limits as prescribed in this proceeding -- are
    properly classified as Part 15 devices and are not required to be
    licensed on a formal basis.

69. The Commission first adopted rules for unlicensed operation of low
    power radio devices in 1938, and the basic construct of this
    regulatory regime continues to apply today.[^179] The Commission
    took this action because it concluded that lower power radio
    frequency devices could be used on a widespread unlicensed basis,
    consistent with the public interest, if the Commission regulated
    their technical capabilities to ensure that they did not interfere
    with the orderly operation and development of radio
    communications.[^180] The requirements for unlicensed operation are
    codified in Part 15 of the Commission rules and apply to a wide
    variety of emissions and devices, including intentional,
    unintentional and incidental radiators.[^181] These requirements
    ensure that such "apparatus" do not transmit energy in a way that
    has a significant detrimental effect on the operation or development
    of the nation's communications network.

70. In setting up the Part 15 regime, the Commission realized that any
    attempt to license *all* transmitters of radio frequency energy
    would be infeasible and contrary to Congress's intent in
    establishing a "rapid, efficient, Nation-wide, and world-wide wire
    and radio communication service."[^182] In this regard, the
    Commission has long recognized that numerous devices emit radio
    frequency energy, often at very low levels, and that such devices
    may be operated by numerous individual users, making individual
    licensing of users impractical.[^183] Recognizing that the
    identification and individual licensing of all devices that affected
    or relied upon radio frequency energy was not practical, the
    Commission, very early in its existence, interpreted Section 301 not
    to require the licensing of devices that did not transmit energy in
    a manner that had any real potential to affect the Nation's
    communications network adversely. In adopting this reading of the
    statute, the Commission recognized that many devices that operate at
    very low power levels and at very short distances are unlikely to
    cause harmful interference and thus would not need to be
    individually licensed.

71. The requirements that apply to Part 15 devices ensure that emissions
    from such unlicensed apparatus do not rise to the level that would
    require licensing. For example, relying on its authority under
    Section 301 to prohibit certain radio uses ("No person shall use or
    operate any apparatus for the transmission of energy or
    communications or signals by radio...except under and in accordance
    with this Act and with a license in that behalf granted under the
    provisions of this Act."), and under Section 303(f) to make
    "regulations not inconsistent with law as it may deem necessary to
    prevent interference between stations and to carry out the
    provisions of this Act,"[^184] the Commission prescribes technical
    requirements which, if exceeded, would require the user of a device
    to acquire an individual license or to cease operation. Thus,
    although certain devices are unlicensed, they are still subject to
    appropriate regulation to ensure that they do not cause harmful
    interference to authorized users of the spectrum. Further, it is
    expressly stated in Part 15 of the Commission's rules that this rule
    part sets out the regulations under which one may operate without an
    individual license, and that any operation that is not in accordance
    with the Part 15 regulations must be licensed under Section 301
    unless exempted elsewhere in the rules.[^185] Rather than require
    all users to be individually licensed initially, the Commission has
    put users on notice that, under certain circumstances, it will
    require an individual license or prohibit their operations. This
    approach has proven to be an effective means for the Commission to
    achieve the stated purposes of the Act ("...to maintain the control
    of the United States over all the channels of radio transmission;
    and to provide for the use of such channels...by persons for limited
    period of time, under licenses granted by Federal
    authority...")[^186] without imposing a licensing requirement on all
    individual users of all devices that emit radio frequency
    energy.[^187]

72. Further, we disagree with Cingular that the Commission -- which had
    concluded in its early decisions that devices operating at very low
    emission levels would not cause interference and thus would not be
    interstate communications requiring individual licensing under
    Section 301 -- no longer has a statutory basis upon which to allow
    unlicensed operation. After Section 301 was amended in 1982 to
    clarify that the Commission's authority also covers intrastate
    communications, the Commission has continued to rely on the harmful
    interference criteria as the basis for allowing unlicensed
    operations under Part 15, consistent with reading Section 301's
    reference to "apparatus for the transmission of energy" not to
    include devices that have no such interference potential.[^188] We
    hereby explicitly adopt that construction of Section 301.

73. Various amendments to the Communications Act demonstrate that
    Congress has been well aware that the Commission permits users to
    operate approved unlicensed devices without a formal "license," but
    has not disapproved that practice. Just the opposite. For example,
    in 1992, when Congress amended Section 302 to add subsection (d)(1),
    it expressly acknowledged the Commission's Part 15 unlicensed
    operations within the statutory scheme. This subsection states, in
    pertinent part, that "the Commission shall prescribe and make
    effective regulations denying equipment authorization (under part 15
    of title 47, Code of Federal Regulations, or any other part of that
    title) for \[certain\] scanning receiver\[s\]."[^189] Scanning
    receivers are unlicensed devices, and Congress wanted to ensure that
    they would not receive transmissions in frequencies allocated to the
    cellular radio service, which is a licensed service and entitled to
    protection under the Act.[^190]

74. As a further example of Congress's acknowledgment of the
    Commission's unlicensed regulatory regime, in 1996, Congress amended
    Section 332 of the Act to recognize State and local authority over
    the placement and construction of certain wireless facilities,
    including "unlicensed wireless service." Section 332(c)(7)(C)(iii)
    defines "unlicensed wireless service" as "the offering of
    telecommunications services using duly authorized devices which do
    not require individual licenses."[^191] Reference to these types of
    devices includes those operating under Part 15, which are "duly
    authorized" pursuant to the Commission's equipment approval program.
    Similarly, in Section 3002(c) of the Balanced Budget Act of 1997,
    which directs the Commission to make additional spectrum available
    by auction, Congress acknowledged the Commission's unlicensed
    regulatory regime by expressly protecting those frequency bands that
    the Commission had already authorized for unlicensed use pursuant to
    Part 15.[^192] Finally, in enacting the Electronic Communications
    Privacy Act of 1986, Congress noted in the legislative record that
    cordless telephones \"are regulated under Part 15, Subpart E of the
    rules of the Federal Communications Commission (FCC), and are not
    licensed.\"[^193]

75. We acknowledge that there is a gray area between those "unlicensed"
    devices that transmit energy but are clearly beyond any reasonable
    application of Section 301's licensing requirement[^194] and those
    operations that are clearly subject to Section 301. As explained
    above, we do not believe it necessary to subject all devices in the
    gray area to the licensing requirements of Section 301. In the
    alternative, however, our Part 15 requirements provide a sufficient
    degree of regulatory oversight, individualized review and approval
    to constitute a "licensing" process that satisfies Section 301
    requirements. While we do not apply the term "license" to the Part
    15 approvals that are required to manufacture and distribute Part 15
    devices, such approvals (*e.g.*, certifications for intentional
    radiators) constitute agency authorization for the manufacture,
    distribution and use of devices that have passed individualized
    requirements. As such, there is little to distinguish in a practical
    or legal sense Part 15 approvals of devices from the more overt
    Section 301 "licenses."

76. Section 301 does not limit the types of licenses that the Commission
    may grant, and the Commission has exercised discretion in developing
    a diverse regulatory scheme. Section 3 of the Act defines "station
    license," "radio station license," or "license" broadly to mean
    "that instrument of authorization required by this Act or the rules
    and regulations of the Commission made pursuant to this Act, for the
    use or operation of apparatus for the transmission of energy, or
    communications, or signals by radio by whatever name the instrument
    may be designated by the Commission."[^195] The Commission's
    licensing regime includes, in addition to "license by rule" and
    site-specific licensing, blanket and wide-area licensing schemes.
    The typical blanket or wide-area licensing scheme allows individual
    customers/users to operate within a network without benefit of
    individual licenses, and the network operator is the sole licensee,
    as is done, for example, in the cellular wireless service. Because
    the network operator can control system design and access, and
    because the Commission has maintained through an individualized
    approval process the ability to control the use of spectrum,
    individual users' rights can be identified and interference between
    users can be avoided; thus, these licensing schemes are a reasonable
    exercise of the Commission's authority under Sections 4(i), 303(f)
    and 303(r) of the Act. Similarly, while the Commission does not
    inspect and test each individual Part 15 device, the Commission's
    review of a representative device for approval before it can be used
    is sufficiently individualized to cover all identical devices. Thus,
    unlicensed devices under Part 15 of the rules may not be operated or
    marketed without prior Commission authorization (certification,
    declaration of conformity or verification) to ensure that they
    operate consistent with the Part 15 technical rules, unless
    expressly exempted.[^196]

77. Moreover, the individualized nature of the Part 15 approval process
    distinguishes this type of review from the "license by rule"
    approach used for Section 307(e) services that are exempted from
    Section 301's licensing requirement. Thus, we disagree with Cingular
    that Section 307(e) is inconsistent with our reading of Section 301.
    Under the licensing exemptions of Section 307(e), certain higher
    power communications services may be provided without any Commission
    review of the provider or of the specific operation that the
    provider intends to provide. Rather, the Commission adopts a set of
    rules that prescribe parameters of operation, and anyone may operate
    the service in any manner within those parameters. In contrast, to
    rely on a Part 15 approval, a Part 15 device cannot differ in any
    significant regard from the exact device that has garnered Part 15
    approval.[^197]

78. Cingular has argued throughout this proceeding that UWB transmission
    systems should be permitted solely on a formal, licensed basis, and
    now in its second petition for reconsideration attacks our statutory
    authority to adopt rules permitting UWB or any other similar
    operation on a Part 15, "unlicensed" basis.[^198] We discussed at
    length in the *1st R&O* the merits of permitting UWB operations on a
    licensed or unlicensed basis, and have otherwise responded to the
    merits of Cingular's various arguments on different aspects of the
    unlicensed rules adopted.[^199] We therefore deny the Petitioner's
    request for reconsideration and affirm our decisions in the *1st
    R&O* and *MO&O*, respectively.

### Harmful interference to cellular, PCS and E911 operations

79. Cingular claims that the Commission's authorization of UWB devices
    was performed without an adequate record to demonstrate that harmful
    interference would not be caused to cellular, PCS and E911
    operations. This claim addresses decisions made in the *1^st^ R&O*
    and could be considered an untimely filed petition. Cingular also
    addresses arguments that were raised by Cingular, Qualcomm and
    Sprint in their petitions for reconsideration of the *1^st^ R&O* and
    thoroughly discussed in the *MO&O*.[^200] Cingular presents no new
    information or data and this portion of its petition could be
    dismissed as repetitious. Cingular raises only one issue that
    addresses the *MO&O* stating that the Commission made contradictory
    statements regarding the record.

80. With regard to contradictory statements regarding the record,
    Cingular indicates that it requested reconsideration of the *1^st^
    R&O* because the Commission failed to consider the interference
    impact to cellular, TDMA and GSM systems.[^201] Cingular states that
    the Commission rejected its request because no data was provided.
    Cingular adds that the Commission, later in the *MO&O*, refused to
    reconsider its standards pending the completion of additional
    testing stating that there had been considerable analysis on every
    possible aspect of interference. However, Cingular argues that there
    is no record support for this statement by the Commission. Cingular
    argues that if no data had been provided regarding cellular
    interference, the Commission could not have considered every
    possible aspect. To demonstrate that there was no discussion in the
    *1^st^ R&O* regarding interference to cellular systems, Cingular
    asserts that the term "cellular" does not appear in the *1^st^
    R&O*.[^202] Cingular believes that this contradiction constitutes
    unreasoned decision making. Cingular also states that it had
    provided data regarding signal and interference levels for TDMA
    cellular and for TDMA and GSM PCS but that the Commission ignored
    all of this evidence.[^203] Cingular argues that the Commission, in
    the *MO&O*, incorrectly stated that Cingular had not provided any
    additional information on other types of modulation techniques that
    could be employed for cellular or for PCS and asserts that this
    statement acknowledges that the Commission failed to consider record
    evidence supplied by Cingular. Based on this, Cingular claims that
    the Commission's decision is subject to reversal.[^204]

81. Cingular mischaracterizes the actions taken by the Commission in its
    *1^st^ R&O* and its *MO&O* and presents several misstatements of
    fact. For example, Cingular claims that the *1^st^ R&O* contained no
    discussion regarding the UWB interference potential to cellular
    applications and that the Commission dismissed or ignored all data.
    However, the *1^st^ R&O* does indeed contain a discussion of
    cellular interference susceptibility at paragraph 192.[^205]
    Cingular also misquotes the statement from the Commission to reach
    the conclusions in its current petition. In its *MO&O*, the
    Commission stated that "\[w\]hile Cingular objects to our not
    providing similar analyses for TDMA and GSM modulation types, we
    based our analysis on the specifications provided by the proponents.
    We note that Cingular has not provided any [additional]{.underline}
    information on other types of modulations that could be employed for
    cellular or for PCS." \[emphasis added\][^206]

82. We recognize that Cingular, on October 12, 2001, submitted an *ex
    parte* letter specifying values for the sensitivity for TDMA
    cellular and PCS receivers and for GSM PCS receivers.[^207] In that
    letter, Cingular also supplies carrier-to-interference
    specifications for these receivers. It is unclear if these values
    were based on test data or, as indicated in Cingular's letter, if
    they only reflect performance specifications. Cingular's reference
    to measurement data only stated that recent measurements in an urban
    area showed that signals were at acceptable levels. Cingular added
    that in cases of severe blockage and/or shadowing that signal levels
    were as low as the minimum stated sensitivity levels. Cingular did
    not indicate whether or not operation was possible at these "severe
    blockage and/or shadowing" levels. Cingular did not supply any data
    regarding co-cell and adjacent-cell noise levels, receiver
    processing gains, or other parameters which would enable a complete
    interference analysis. Cingular simply claimed that its systems
    operated at the minimum specified receiver sensitivities.

83. The Commission concentrated its discussion on interference
    potentials to CDMA PCS operations since this constituted the
    majority of analyses and data submitted in this proceeding and there
    appeared to be a lack of actual test data regarding TDMA and GSM
    systems. While the discussion on the impact to cellular operations
    is considerably less than the amount of discussion on the potential
    impact to PCS operations, it must be recognized that, with limited
    exceptions, the Commission did not authorize UWB devices to operate
    in the cellular bands or in the PCS frequency bands.[^208] Consumer
    UWB devices are not permitted to operate below 3100 MHz. Thus,
    consumer UWB devices are so far removed from the spectrum used for
    cellular applications that it is unlikely that measurable emissions
    from the fundamental component will even appear the cellular bands.
    Rather, it is likely that that any emissions appearing within the
    cellular bands will be random spurious emissions from associated
    digital circuitry and that any potential impact to cellular
    operations will be less than that caused by existing digital
    devices. Further, the CDMA PCS systems, according to information
    submitted by Sprint and Qualcomm, appeared to be at least as
    sensitive to harmful interference as the receivers specified by
    Cingular. Thus, the Commission concentrated its analysis on the test
    data it had on hand. This was a reasonable approach and produced
    interference analysis results that similarly apply to TDMA and GSM
    systems. When Cingular requested reconsideration of the decision in
    the *1^st^ R&O*, it supplied no additional data that could be used
    by the Commission to come to a different conclusion. Since, as
    stated in the *MO&O*, Cingular did not file any additional data in
    this proceeding, no further analysis of cellular, TDMA or GSM
    systems was possible. Accordingly, there is no contradiction in the
    statements in the *MO&O* that are cited by Cingular. The Commission
    did consider the interference aspects to all types of cellular and
    PCS operations using the best data it had before it.

84. There was only one change in the *MO&O* that affected the level of
    emissions appearing within the PCS frequency bands and no changes
    that affected the levels of emissions appearing within the cellular
    frequency bands. Prior to the *MO&O*, the equivalent isotropically
    radiated power (EIRP) limit produced in the PCS bands by
    through-wall imaging systems operating above 1990 MHz was limited to
    ‑51.3 dBm/MHz. The Commission, in the *MO&O*, increased this
    emission limit to -41.3 dBm and explained why such an increase would
    not result in harmful interference.[^209] However, the petition from
    Cingular does not address, much less object to, any of the rule
    changes implemented in the *MO&O*. Instead, Cingular continues to
    argue against actions taken by the Commission in the *1^st^ R&O*.
    Cingular has provided no new information, presenting the same
    arguments it employed in its petition for reconsideration of the
    *1^st^ R&O*. Those arguments already were addressed in the *MO&O*.
    As noted by XSI, Cingular states repeatedly that the Commission
    "rejected" or "dismissed" or "ignored" or "disregarded" or
    "discounted" arguments Cingular (and others) placed in the
    record.[^210] However, a reading of the *1^st^ R&O* and the *MO&O*
    clearly shows that the Commission considered the views and data
    submitted by the commenting parties. The Commission simply disagreed
    with some of these submissions and explained the basis for its
    disagreement within the *1^st^ R&O* and again in the *MO&O* in
    response to the first petitions for reconsideration. The Commission
    fully considered the comments, test data, interference analyses and
    other material filed in this proceeding. Full opportunity for all
    affected parties to comment has been afforded.

85. Petitions for reconsideration are not granted for the purpose of
    altering our basic findings or debating matters that have been fully
    considered and substantively settled.[^211] Absent new facts and
    information, we find Cingular's arguments about the interference
    potential of UWB devices to be repetitive and without merit.
    Accordingly, the portion of Cingular's petition for reconsideration
    claiming that the Commission's authorization of UWB devices was
    performed without an adequate record to demonstrate that harmful
    interference would not be caused to cellular, PCS and E911
    operations, including Cingular's claim that the Commission made
    contradictory statements in its *MO&O* regarding the record in this
    proceeding, is denied.

### Rights of incumbent cellular and PCS licensees

86. Cingular claims that the *MO&O* fails to adequately protect the
    rights of incumbent cellular and PCS licensees by undermining the
    exclusivity rights of the licensees, by failing to include these
    licensees in a coordination process with UWB operators, and by
    failing to lower the emission limits in the PCS and cellular
    frequency bands for indoor UWB devices.[^212] These claims by
    Cingular were raised in its petition for reconsideration of the
    *1^st^ R&O* and were denied by the Commission in its *MO&O*.[^213]
    Cingular presents no new evidence or information to support its
    claims. Thus, Cingular's claims amount to a petition for
    reconsideration of the *1^st^ R&O* and should be considered an
    untimely filed petition that can be dismissed as repetitious.

87. Cingular also argues that the Commission, in the *MO&O*,
    mischaracterized a recent court opinion, *AT&T Wireless v. FCC*,
    [^214] when it stated that the Court "affirmed the Commission's
    decision that even an exclusive licensee cannot object to secondary
    use of its spectrum as long as no harmful interference
    results."[^215] Cingular argues that there was no affirmation, as
    such, but instead that the court was remanding certain issues to the
    Commission. Cingular also contends that the court never endorsed all
    secondary spectrum use in the absence of harmful interference
    asserting that the premise of the case was that there would be no
    degradation of service. Cingular adds that the court did not endorse
    secondary users causing objectionable interference and argues that
    the court's decision was specifically subject to the harmful
    interference issue being resolved in the remand.[^216]

88. In its decision in the *AT&T Wireless v. FCC* case, the Court,
    *inter alia*, dismissed various claims by the petitioners,[^217] but
    found that in rejecting a report advocating a specific interference
    criterion, the Commission was unclear as to its choice of the
    appropriate interference threshold supporting its conclusion that
    AirCell\'s operations would not cause harmful interference to
    terrestrial cellular systems. Specifically, where the Commission
    concluded that the report had relied on \"unrealistic assumptions,
    including the use of an unrealistically low interference
    threshold,\" the court remanded for the Commission to clarify the
    justification for its view that use of the petitioner's proposed
    threshold of minus 124 dBm was too conservative and that an
    interference threshold of minus 117 dBm was more realistic.[^218]
    The court notes, however, that it remanded so that the Commission
    could explain why it considered one interference threshold
    preferable to another, but not to defend the threshold ultimately
    selected.[^219]

89. We find that Cingular's objection is without merit. The Commission
    correctly noted in the *MO&O* and the *AirCell Remand Order* that
    the court had remanded the Commission to explain the selection of
    the interference criterion, and that the court had affirmed the
    Commission's finding that absent harmful interference the
    petitioner's rights as a licensee were not changed by the AirCell
    waiver.[^220] On remand, the Commission found no interference to the
    wireless carrier's operations, which is the case here.[^221] The
    court also found that Commission rules proscribe only harmful
    interference within a given carrier\'s cellular geographic service
    area ("CGSA"), and that AirCell\'s new system did not infringe upon
    petitioners\' rights as exclusive licensees to be protected from
    harmful interference.[^222] The court specifically referred to
    "harmful interference" and not degradation of service or
    objectionable interference as cited by Cingular.

90. With the exception of GPRs and wall imaging systems, UWB devices do
    not operate within the PCS or cellular bands although they may
    produce emissions within these bands. Cingular's claim of
    exclusivity would prohibit the Commission from allowing any
    emissions to fall within a licensee's cellular or PCS bands, even if
    those emissions are sufficiently attenuated to not cause harmful
    interference to the operation of the cellular or PCS systems. Thus,
    Cingular's interpretation of the exclusivity provided to a cellular
    or PCS license also would preclude the Commission from licensing
    additional PCS or cellular stations, as well as public safety and
    other radio operations, in different frequency bands since those
    stations produce emissions outside of their licensed band of
    operation.[^223] Clearly, this is not the case. We also note that
    the operation of unlicensed devices in the PCS and cellular bands
    has been permitted under Part 15 at higher emission levels than
    those produced by UWB devices since before the allocation of the
    cellular and PCS services.[^224] We disagree with Cingular's concern
    about the Commission's characterization of the Court's opinion in
    *AT&T Wireless v. FCC*. The Court affirmed, in the AirCell waiver
    proceeding, that an exclusive licensee could not object to the
    Commission's policy decision to permit secondary use rights where
    such secondary use did not cause harmful interference.[^225]

91. The Commission has already fully considered the issues presented by
    Cingular and the comments. Cingular has provided no new information
    but, with one exception, continues to present the same arguments it
    employed in its petition for reconsideration of the *1^st^ R&O* that
    were addressed in the *MO&O*. The statement in the *MO&O* addressing
    XSI's comment that the court had affirmed a decision[^226] does not
    constitute reversible error especially since the Commission
    correctly referenced this case as a remand and since the reference
    to this case does not constitute the Commission's sole argument for
    the denial of Cingular's claim. Full opportunity for all affected
    parties to comment has been afforded and we have fully considered
    all relevant matters in the record. Absent new facts and
    information, we find Cingular's arguments about protecting the
    rights of incumbent cellular and PCS licensees to be repetitive and
    without merit. According, this portion of Cingular's petition for
    reconsideration is denied.

## Interference to C-Band Fixed Satellite Service

92. [Background]{.underline}. On June 17, 2002, SIA filed a Petition for
    Reconsideration of the *1^st^ R&O*. In this petition, SIA argued
    that the Commission's analysis in the *1^st^ R&O* regarding the
    interference potential to FSS operation in the 3.7-4.2 GHz band was
    inconsistent because it developed a protection criteria based on
    indoor UWB operation but also permitted these devices to operate
    outdoors. SIA argued that the Commission relied on a building to
    serve as a buffer between the UWB emitter and the FSS earth station
    but that this attenuation can not be assumed for outdoor UWB
    devices. It requested that emissions from outdoor UWB devices be
    reduced in the FSS band. SIA also argued that the Commission did not
    meaningfully address the minimum separation distances specified in
    the NTIA report for protecting FSS stations from UWB emissions,
    indicating that the required separation distances extended up to
    tens of kilometers. On January 10, 2003, SIA submitted a technical
    analysis demonstrating that the peak level emissions from a single
    UWB device could cause harmful interference to FSS reception at a
    distance of up to 4.4 km. The Commission denied the SIA petition,
    along with the later technical analysis, adding that appropriate
    action would be taken to protect FSS stations should tests or other
    sources provide any indication that its standards are not adequate
    to protect the authorized services from harmful interference.[^227]

93. On May 22, 2003, SIA filed a Petition for Reconsideration of the
    *MO&O*. SIA argues that the 0 dB interference-to-noise ratio (I/N)
    used by the Commission in its analysis in the *1^st^ R&O* will
    result in FSS stations receiving harmful interference.[^228] SIA
    requests that an I/N of -10 dB be applied. SIA also argues that the
    assumptions used in its technical arguments contained in its
    technical analysis of January 10, 2003, are appropriate and are
    necessary to evaluate the UWB interference to FSS receivers.[^229]
    Specifically, SIA states that the Commission was in error in
    characterizing its analysis as being overly conservative, citing
    five areas that it believes were incorrectly addressed by the
    Commission: 1) the low elevation angles of the FSS antenna; 2) the
    presence of natural and man made structures resulting in attenuation
    of the UWB emissions; 3) the probability that UWB devices would emit
    at the maximum peak emission level; 4) the low relative heights of
    the FSS and UWB antennas; and 5) the Commission's denial in the
    *1^st^ R&O* of the use of a -10 dB I/N. SIA states that the
    Commission questioned that FSS receivers will operate with antennas
    directed low towards the horizon, indicating that such low elevation
    angles are commonplace and necessary. SIA also states that it did
    not assume that there would be no intervening objects in the
    calculated separation distances between the UWB emitter and the FSS
    receiving antenna but only demonstrated that a UWB device that was
    visible to an FSS receiving antenna and within 4.4 km would result
    in interference. SIA indicates that it assumed that UWB devices may
    operate at the maximum peak power levels permitted under the rules
    and that, as omnidirectional devices, would transmit their signals
    in the direction of the FSS receiving antenna. SIA adds that if the
    Commission is confident that outdoor UWB devices will not radiate at
    the peak limit then it should lower the limit.[^230] SIA also states
    that the relative heights of the UWB and FSS antenna have a *de
    minimus* impact on the required separation distances. SIA states
    that the Commission criticized SIA's reliance on a ‑10 dB I/N but
    that SIA can demonstrate a basis for requiring an I/N of -10 to
    -12.2 dB. Finally, SIA states that FSS antennas can be pointed at
    buildings and still have ample clearance for line-of-sight satellite
    reception, arguing that the 10 dB isolation claimed by XSI due to
    offset from the satellite antenna does not exist.[^231] SIA provides
    an attached engineering statement.

94. [Comments/Discussion]{.underline}. XSI states that the SIA petition
    offers no facts or laws that were not previously available, adding
    that the Commission has already dealt with all of the arguments
    raised by SIA, including the I/N, peak versus average levels, and
    earth station geometries.[^232] XSI adds that the petition should be
    dismissed as repetitious since the bulk of the petition does nothing
    more than dispute the findings in the *MO&O* without adding newly
    available fact or analysis. We concur with this assessment. The
    Commission did not make any changes in the *MO&O* that affect the
    levels of the emissions that may appear in the FSS frequency bands.
    Rather, SIA continues to dispute the issue of a relative I/N ratio
    that was addressed in the *1^st^ R&O*. The time is long past for
    filing a petition for reconsideration of that decision. SIA also
    disputes the Commission's statement in the *MO&O* that the
    interference scenario employed by SIA in its technical analysis is
    overly conservative. SIA continues to argue the unlikely scenario
    that UWB emissions are subject to a propagation loss that is
    applicable only when there is a clear line-of-sight between the UWB
    emitter and the FSS receiving antenna,[^233] that the UWB devices
    will operate at relatively low pulse repetition frequencies
    producing high level peak emissions, and that the FSS receiver will
    respond fully to the peak level emissions from the UWB emitter. SIA
    does not address the Commission's statement that low elevation FSS
    systems generally are mounted in secured areas that are not readily
    accessible to the public nor has it ever provided any evidence that
    FSS receivers will respond fully to the peak emission levels from
    UWB devices. Indeed, SIA presents no new information to substantiate
    its claims but only continues to argue against the Commission's
    decision. Accordingly, SIA's current Petition for Reconsideration
    can be considered repetitious of its earlier Petition for
    Reconsideration of the *1^st^ R&O* and this petition therefore is
    dismissed.

95. [Alion analysis]{.underline}. Since the filing of the SIA Petition
    for Reconsideration, the Coalition of C-Band Constituents
    ("Coalition") contracted with Alion Science and Technology ("Alion")
    to determine what, if any, interference potential exists to FSS
    reception from UWB operation. A test report on this matter was
    submitted to the Commission on February 11, 2004.[^234] The Alion
    study concludes that FSS receivers will experience "complete
    reception failure at currently regulated UWB power levels assuming
    emitter densities currently found in the environment of common
    wireless-based consumer units."[^235] Based on this report, the
    Coalition, in its cover letter of February 18, 2004, concludes that
    the Commission must reduce the level of emissions permitted in the
    3700-4200 MHz band by 21 dB.

96. The Alion study is based on multiple worst-case assumptions, most of
    which simply are not realistic. For example, this study is founded
    on the premise that a large number of UWB devices will be near the
    FSS receiver and will contribute significantly to the aggregate
    interference level. Specifically, the study assumes that ninety
    percent of the UWB devices distributed within 1000 meters of the FSS
    station, 70 percent between one and two km, 50 percent within two
    and three km, etc. have a direct line-of-sight propagation path into
    the FSS receive antenna without attenuation from any intervening
    objects.[^236] In addition, it is assumed that UWB transmitters may
    be located as close as 30 meters to the FSS antenna, that all UWB
    emitters within a 5 km radius are pointed directly at the FSS
    antenna, and that all UWB emitters operate at a 100 % activity
    factor. Further, the Alion analysis assumes that every UWB device
    operating within 5 km of the FSS station produces the maximum
    permissible power spectral density (PSD) level within the pass band
    of the FSS receiver. The Coalition has further exacerbated the
    worst-case results from the Alion study by applying unsupported and
    unreasonable projections with respect to UWB device proliferation.
    The Coalition assumes that UWB devices will replace all existing
    Part 15 cordless telephones, wireless security applications, and
    wireless data communications and will be used for communications
    within and between vehicles, resulting in an estimated 64 UWB
    devices per acre or 1.24 million UWB devices, all operating
    continuously, within 5 km of an FSS receiver.[^237]

97. The current UWB regulations severely restrict what types of devices
    may be operated outdoors. Outdoor usage is limited to hand-held,
    very short range, peer-to-peer operations that likely will be of
    extremely short duration. This hand-held restriction precludes the
    mounting of UWB devices in transportation vehicles.[^238] Because of
    these restrictions, only a small percentage of UWB devices, likely
    much less than 5 percent, will be operated outdoors and these will
    have extremely low activity factors. In addition, the hand-held
    requirement essentially ensures that a large percentage of UWB units
    operated outdoors will be subject to attenuation from head and body
    shielding from the user.[^239] Further, outdoor UWB devices would be
    operated close to the ground and the resulting multipath
    interactions will result in the emissions from these devices
    attenuating at a much faster rate than was calculated by Alion using
    free space propagation. All non-hand-held UWB devices must be
    located indoors where their emissions would be subject to an average
    12 dB attenuation from shielding provided by the building.[^240] The
    emissions from indoor UWB devices also would be subject to a
    propagation attenuation factor much greater than the free space
    model.[^241] Several ranges of activity factors have been
    hypothesized for indoor UWB applications and these are well below
    the 100 percent level employed in the Alion study.

98. In addition to the above, UWB devices separated from the FSS site by
    any appreciable distance, regardless of whether they are operated
    outdoors or indoors, are likely to encounter multiple intervening
    objects that provide considerable additional attenuation to the
    emissions.[^242] Because FSS receive sites are outdoors, and are
    usually located to avoid radio noise from other sources, it is
    highly unlikely that any UWB devices will be operated within 30
    meters unless those devices are operated by FSS personnel. Further,
    we anticipate that many UWB transmitters will employ directional
    patch antennas and would not necessarily direct their signals toward
    the FSS site. In addition, not all UWB devices will operate with
    their emissions centered at 4 GHz nor will all UWB devices produce
    spectral lines that appear in the passband of an FSS receiver. It is
    expected that UWB operations, along with their associated maximum
    power density levels, will be distributed over several portions of
    the entire authorized frequency band (3.1-10.6 GHz) and not
    concentrated only within a single 500 MHz (3.7‑4.2 GHz) sub-band.
    Finally, we disagree that UWB devices will operate at the density
    levels speculated by the Coalition. Because our current standards
    effectively limit UWB to a transmission range of only 10 meters, UWB
    technology is not expected to be used as cordless telephones or
    security systems. We expect that most consumer devices will continue
    to operate using technologies that can operate in other frequency
    bands available under Part 15.

99. The Commission was able to duplicate the Alion study, obtaining
    similar results when using the same assumptions Alion employed. The
    Commission then recalculated this analysis based on more realistic
    operating conditions, assuming that many UWB devices would be
    located indoors where the building would provide additional path
    loss to the outdoor satellite receive antennas, and obtained results
    that more than offset the 21 dB of attenuation requested by the
    Coalition.[^243] The Commission also found that the large majority
    of the interference potential is caused by the UWB device that is
    near the main beam of the FSS receiving station. The aggregate
    contribution from the remainder of the assumed UWB devices is
    negligible. As evaluated by Alion, the calculation for increasing
    the aggregate contribution from 1000 continuously operating UWB
    transmitters to 1.24 million transmitters accounts for 31 dB of the
    21 dB additional attenuation requested by the Coalition. Based on
    these two offsets to the Coalition's requested protection criteria,
    we find no justification to reduce the UWB emission levels in the
    FSS frequency band. However, we will continue to monitor this
    situation and will take whatever appropriate action is necessary to
    ensure that UWB operation does not result in harmful interference to
    FSS receivers. If a Part 15 device causes interference it is
    required to remedy the interference or to cease operation.[^244] 
    The remedy could be as simple as relocating the UWB device away from
    a window.  In any event, the Commission will investigate any
    interference complaints from UWB devices to the authorized radio
    services, will take steps to ensure that harmful interference is
    corrected, and will take whatever enforcement actions may be deemed
    necessary.

# Administrative Provisions

100. [Paperwork Reduction Act of 1995 Analysis]{.underline}. This
     document contains modified information collection requirements
     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
     new or modified information collection requirements contained in
     this proceeding.

101. The Commission will send a copy of this Second Report & Order and
     Second Memorandum Opinion and Order in a report to be sent to
     Congress and the General Accounting Office pursuant to the
     Congressional Review Act, *[see]{.underline}* 5 U.S.C.
     801(a)(1)(A).

102. [Final Regulatory Flexibility Certification]{.underline}. The
     Regulatory Flexibility Act of 1980, as amended (RFA),[^245]
     requires that a regulatory flexibility analysis be prepared for
     notice-and-comment rule making proceedings, unless the agency
     certifies that "the rule will not, if promulgated, have a
     significant economic impact on a substantial number of small
     entities."[^246] The RFA generally defines the term "small entity"
     as having the same meaning as the terms "small business," "small
     organization," and "small governmental jurisdiction."[^247] In
     addition, the term "small business" has the same meaning as the
     term "small business concern" under the Small Business Act.[^248] 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).[^249]

103. In this Second Report and Order and Second Memorandum Opinion and
     Order, we are implementing a change to the rules to facilitate the
     operation of wideband unlicensed transmitters. We also are
     responding to two petitions for reconsideration regarding rules
     that permit the marketing and operation of 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. 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.
     Further, as noted in the text we have continued to apply
     conservative limits to the standards applicable for UWB operation,
     until such time as we gain additional experience, to ensure that
     harmful interference would not be caused to other radio spectrum
     users. Further, the changes adopted in this proceeding will not
     affect any party legally manufacturing or marketing UWB devices.
     Thus, we expect that our actions do not amount to a significant
     economic impact. Accordingly, we certify that the rules being
     adopted in this Memorandum Opinion and Order will not have a
     significant economic impact on a substantial number of small
     entities.

104. The Commission will send a copy of the Second Report and Order and
     Second Memorandum Opinion and Order, including a copy of this Final
     Regulatory Flexibility Certification, in a report to Congress
     pursuant to the Congressional Review Act.[^250] In addition, the
     Second Report and Order and Second Memorandum Opinion and Order and
     this final certification will be sent to the Chief Counsel for
     Advocacy of the SBA, and will be published in the Federal
     Register.[^251]

105. [Ordering Clauses]{.underline}. IT IS ORDERED that the Petition for
     Reconsideration from Cingular, Inc. IS DENIED. IT IS ORDERED that
     the Petition for Reconsideration from Satellite Industry
     Association IS DISMISSED. IT ALSO IS ORDERED that Part 15 of the
     Commission's Rules and Regulations IS AMENDED as specified in
     Appendix A, effective 30 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.

106. IT IS FURTHER ORDERED that the Commission's Consumer and
     Governmental Affairs Bureau, Reference Information Center, SHALL
     SEND a copy of this Second Report and Order and Second Memorandum
     Opinion and Order, including the Final Regulatory Flexibility
     Certification, to the Chief Counsel for Advocacy of the Small
     Business Administration.

107. IT IS FURTHER ORDERED that this proceeding IS TERMINATED.

108. For further information regarding this Second Report and Order and
     Second Memorandum Opinion and Order, contact John A. Reed, Office
     of Engineering and Technology, (202) 418-2455,
     [john.reed@fcc.gov](mailto:jreed@fcc.gov).

     FEDERAL COMMUNICATIONS COMMISSION

Marlene H. Dortch

Secretary

**Appendix A**

**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, 336 and 544A.

2.  Section 15.35 is amended by revising paragraph (b) to read as
    follows:

    Section 15.35 [Measurement detector functions and
    bandwidths]{.underline}.

    \* \* \* \* \*

\(b\) Unless otherwise specified, on any frequency or frequencies above
1000 MHz, the radiated emission limits are based on the use of
measurement instrumentation employing an average detector function.
Unless otherwise specified, measurements above 1000 MHz shall be
performed using a minimum resolution bandwidth of 1 MHz. When average
radiated emission measurements are specified in this part, including
average emission measurements below 1000 MHz, there also is a limit on
the peak level of the radio frequency emissions. Unless otherwise
specified, *e.g.*, see §§ 15.250, 15.252, 15.255, and 15.509‑15.519 of
this part, the limit on peak radio frequency emissions is 20 dB above
the maximum permitted average emission limit applicable to the equipment
under test. This peak limit applies to the total peak emission level
radiated by the device, *e.g.*, the total peak power level. Note that
the use of a pulse desensitization correction factor may be needed to
determine the total peak emission level. The instruction manual or
application note for the measurement instrument should be consulted for
determining pulse desensitization factors, as necessary.

\* \* \* \* \*

3\. Section 15.215 is amended by revising paragraph (c), to read as
follows:

Section 15.215 [Additional provisions to the general radiated emission
limitations]{.underline}.

\* \* \* \* \*

\(c\) Intentional radiators operating under the alternative provisions
to the general emission limits, as contained in §§ 15.217 through 15.257
and in Subpart E of this part, must be designed to ensure that the 20 dB
bandwidth of the emission, or whatever bandwidth may otherwise be
specified in the specific rule section under which the equipment
operates, is contained within the frequency band designated in the rule
section under which the equipment is operated. The requirement to
contain the designated 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 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.

4\. A new Section 15.250 is added to read as follows:

Section 15.250 [Operation of wideband systems within the band 5925-7250
MHz]{.underline}.

\(a\) The -10 dB bandwidth of a device operating under the provisions of
this section must be contained within the 5925-7250 MHz band under all
conditions of operation including the effects from stepped frequency,
frequency hopping or other modulation techniques that may be employed as
well as the frequency stability of the transmitter over expected
variations in temperature and supply voltage.

\(b\) The -10 dB bandwidth of the fundamental emission shall be at least
50 MHz. For transmitters that employ frequency hopping, stepped
frequency or similar modulation types, measurement of the -10 dB minimum
bandwidth specified in this paragraph shall be made with the frequency
hop or step function disabled and with the transmitter operating
continuously at a fundamental frequency following the provisions of
Section 15.31(m) of this part.

\(c\) Operation on board an aircraft or a satellite is prohibited.
Devices operating under this section may not be employed for the
operation of toys. Except for operation onboard a ship or a terrestrial
transportation vehicle, the use of a fixed outdoor infrastructure is
prohibited. A fixed infrastructure includes antennas mounted on outdoor
structures, *e.g.*, antennas mounted on the outside of a building or on
a telephone pole.

\(d\) Emissions from a transmitter operating under this section shall
not exceed the following equivalent isotropically radiated power (EIRP)
density levels:

\(1\) The radiated emissions above 960 MHz from a device operating under
the provisions of this section shall not exceed the following RMS
average limits based on measurements using a 1 MHz resolution bandwidth:

+--------------------------------------+-------------------------------+
| Frequency in MHz                     | EIRP in dBm                   |
+--------------------------------------+-------------------------------+
| 960-1610                             | -75.3                         |
|                                      |                               |
| 1610-1990                            | -63.3                         |
|                                      |                               |
| 1990-3100                            | -61.3                         |
|                                      |                               |
| 3100-5925                            | -51.3                         |
|                                      |                               |
| 5925-7250                            | -41.3                         |
|                                      |                               |
| 7250-10600                           | -51.3                         |
|                                      |                               |
| Above 10600                          | -61.3                         |
+--------------------------------------+-------------------------------+

\(2\) In addition to the radiated emission limits specified in the table
in paragraph (d)(1) of this section, transmitters operating under the
provisions of this section shall not exceed the following RMS average
limits when measured using a resolution bandwidth of no less than 1 kHz:

+--------------------------------------+-------------------------------+
| Frequency in MHz                     | EIRP in dBm                   |
+--------------------------------------+-------------------------------+
| 1164-1240                            | -85.3                         |
|                                      |                               |
| 1559-1610                            | -85.3                         |
+--------------------------------------+-------------------------------+

\(3\) 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 and this 50 MHz bandwidth must be contained
within the 5925-7250 MHz band. The peak EIRP limit is 20 log (RBW/50)
dBm where RBW is the resolution bandwidth in megahertz that is employed
by the measurement instrument. RBW shall not be lower than 1 MHz or
greater than 50 MHz. The video bandwidth of the measurement instrument
shall not be less than RBW. If RBW is greater than 3 MHz, the
application for certification filed with the Commission shall contain a
detailed description of the test procedure, calibration of the test
setup, and the instrumentation employed in the testing.

\(4\) Radiated emissions at or below 960 MHz shall not exceed the
emission levels in Section 15.209 of this part.

\(5\) Emissions from digital circuitry used to enable the operation of
the transmitter may comply with the limits in Section 15.209 of this
chapter provided it can be clearly demonstrated that those emissions are
due solely to emissions from digital circuitry contained within the
transmitter and the emissions are not intended to be radiated from the
transmitter's antenna. Emissions from associated digital devices, as
defined in Section 15.3(k) of this chapter, *e.g.*, emissions from
digital circuitry used to control additional functions or capabilities
other than the operation of the transmitter, are subject to the limits
contained in Subpart B of Part 15 of this chapter. Emissions from these
digital circuits shall not be employed in determining the ‑10 dB
bandwidth of the fundamental emission or the frequency at which the
highest emission level occurs.

\(e\) Measurement procedures:

\(1\) All emissions at and below 960 MHz are based on measurements
employing a CISPR quasi-peak detector. Unless otherwise specified, all
RMS average emission levels specified in this section are to be measured
utilizing a 1 MHz resolution bandwidth with a one millisecond dwell over
each 1 MHz segment. The frequency span of the analyzer should equal the
number of sampling bins times 1 MHz and the sweep rate of the analyzer
should equal the number of sampling bins times one millisecond. The
provision in Section 15.35(c) of this part that allows emissions to be
averaged over a 100 millisecond period does not apply to devices
operating under this section. The video bandwidth of the measurement
instrument shall not be less than the resolution bandwidth and trace
averaging shall not be employed. The RMS average emission measurement is
to be repeated over multiple sweeps with the analyzer set for maximum
hold until the amplitude stabilizes.

\(2\) The peak emission measurement is to be repeated over multiple
sweeps with the analyzer set for maximum hold until the amplitude
stabilizes.

\(3\) For transmitters that employ frequency hopping, stepped frequency
or similar modulation types, the peak emission level measurement, the
measurement of the RMS average emission levels, and the measurement to
determine the frequency at which the highest level emission occurs shall
be made with the frequency hop or step function active. Gated signals
may be measured with the gating active. The provisions of Section
15.31(c) of this part continue to apply to transmitters that employ
swept frequency modulation.

\(4\) The ‑10 dB bandwidth is based on measurement using a peak
detector, a 1 MHz resolution bandwidth, and a video bandwidth greater
than or equal to the resolution bandwidth.

\(5\) Alternative measurement procedures may be considered by the
Commission.

5\. A new Section 15.252 is added to read as follows:

Section 15.252 [Operation of wideband vehicular radar systems within the
bands 16.2-17.7 GHz and 23.12-29.0 GHz]{.underline}.

\(a\) Operation under this section is limited to field disturbance
sensors that are mounted in terrestrial transportation vehicles.
Terrestrial use is limited to earth surface-based, non-aviation
applications. Operation within the 16.2-17.7 GHz band is limited to
field disturbance sensors that are used only for back-up assistance and
that operate only when the vehicle is engaged in reverse.

\(1\) The -10 dB bandwidth of the fundamental emission shall be located
within the 16.2‑17.7 GHz band or within the 23.12‑29.0 GHz band,
exclusive of the 23.6-24.0 GHz restricted band, as appropriate, under
all conditions of operation including the effects from stepped
frequency, frequency hopping or other modulation techniques that may be
employed as well as the frequency stability of the transmitter over
expected variations in temperature and supply voltage.

\(2\) The ‑10 dB bandwidth of the fundamental emission shall be 10 MHz
or greater. For transmitters that employ frequency hopping, stepped
frequency or similar modulation types, measurement of the -10 dB minimum
bandwidth specified in this paragraph shall be made with the frequency
hop or step function disabled and with the transmitter operating
continuously at a fundamental frequency following the provisions of
Section 15.31(m) of this part.

\(3\) For systems operating in the 23.12-29.0 GHz band, the frequencies
at which the highest average emission level and at which the highest
peak level emission appear shall be greater than 24.075 GHz.

\(4\) 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. The operation of these devices shall be related
to the proper functioning of the transportation vehicle, *e.g.*,
collision avoidance.

\(b\) Emissions from a transmitter operating under this section shall
not exceed the following equivalent isotropically radiated power (EIRP)
density levels:

\(1\) For transmitters operating in the 16.2-17.7 GHz band, the RMS
average radiated emissions above 960 MHz from a device operating under
the provisions of this section shall not exceed the following EIRP
limits based on measurements using a 1 MHz resolution bandwidth:

+--------------------------------------+-------------------------------+
| Frequency in MHz                     | EIRP in dBm                   |
+--------------------------------------+-------------------------------+
| 960-1610                             | -75.3                         |
|                                      |                               |
| 1610-16,200                          | -61.3                         |
|                                      |                               |
| 16,200-17,700                        | -41.3                         |
|                                      |                               |
| Above 17,700                         | -61.3                         |
+--------------------------------------+-------------------------------+

\(2\) For transmitters operating in the 23.12-29.0 GHz band, the RMS
average radiated emissions above 960 MHz from a device operating under
the provisions of this section shall not exceed the following EIRP
limits based on measurements using a 1 MHz resolution bandwidth:

+--------------------------------------+-------------------------------+
| Frequency in MHz                     | EIRP in dBm                   |
+--------------------------------------+-------------------------------+
| 960-1610                             | -75.3                         |
|                                      |                               |
| 1610-23,120                          | -61.3                         |
|                                      |                               |
| 23,120-23,600                        | -41.3                         |
|                                      |                               |
| 23,600-24,000                        | -61.3                         |
|                                      |                               |
| 24,000-29,000                        | -41.3                         |
|                                      |                               |
| Above 29,000                         | -61.3                         |
+--------------------------------------+-------------------------------+

\(3\) In addition to the radiated emission limits specified in the
tables in paragraphs (b)(1) and (b)(2) of this section, transmitters
operating under the provisions of this section shall not exceed the
following RMS average EIRP limits when measured using a resolution
bandwidth of no less than 1 kHz:

+--------------------------------------+-------------------------------+
| Frequency in MHz                     | EIRP in dBm                   |
+--------------------------------------+-------------------------------+
| 1164-1240                            | -85.3                         |
|                                      |                               |
| 1559-1610                            | -85.3                         |
+--------------------------------------+-------------------------------+

\(4\) 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 and this 50 MHz bandwidth must be contained
within the 16.2-17.7 GHz band or the 24.05-29.0 GHz band, as
appropriate. The peak EIRP limit is 20 log (RBW/50) dBm where RBW is the
resolution bandwidth in MHz employed by the measurement instrument. RBW
shall not be lower than 1 MHz or greater than 50 MHz. Further, RBW shall
not be greater than the -10 dB bandwidth of the device under test. For
transmitters that employ frequency hopping, stepped frequency or similar
modulation types, measurement of the -10 dB minimum bandwidth specified
in this paragraph shall be made with the frequency hop or step function
disabled and with the transmitter operating continuously at a
fundamental frequency. The video bandwidth of the measurement instrument
shall not be less than RBW. The limit on peak emissions applies to the
50 MHz bandwidth centered on the frequency at which the highest level
radiated emission occurs. If RBW is greater than 3 MHz, the application
for certification shall contain a detailed description of the test
procedure, the instrumentation employed in the testing, and the
calibration of the test setup.

\(5\) Radiated emissions at or below 960 MHz shall not exceed the
emission levels in Section 15.209 of this part.

\(6\) Emissions from digital circuitry used to enable the operation of
the transmitter may comply with the limits in Section 15.209 of this
chapter provided it can be clearly demonstrated that those emissions are
due solely to emissions from digital circuitry contained within the
transmitter and the emissions are not intended to be radiated from the
transmitter's antenna. Emissions from associated digital devices, as
defined in Section 15.3(k) of this chapter, *e.g.*, emissions from
digital circuitry used to control additional functions or capabilities
other than the operation of the transmitter, are subject to the limits
contained in Subpart B of Part 15 of this chapter. Emissions from these
digital circuits shall not be employed in determining the ‑10 dB
bandwidth of the fundamental emission or the frequency at which the
highest emission level occurs.

\(c\) Measurement procedures:

\(1\) All emissions at and below 960 MHz are based on measurements
employing a CISPR quasi-peak detector. Unless otherwise specified, all
RMS average emission levels specified in this section are to be measured
utilizing a 1 MHz resolution bandwidth with a one millisecond dwell over
each 1 MHz segment. The frequency span of the analyzer should equal the
number of sampling bins times 1 MHz and the sweep rate of the analyzer
should equal the number of sampling bins times one millisecond. The
provision in Section 15.35(c) of this part that allows emissions to be
averaged over a 100 millisecond period does not apply to devices
operating under this section. The video bandwidth of the measurement
instrument shall not be less than the resolution bandwidth and trace
averaging shall not be employed. The RMS average emission measurement is
to be repeated over multiple sweeps with the analyzer set for maximum
hold until the amplitude stabilizes.

\(2\) The peak emission measurement is to be repeated over multiple
sweeps with the analyzer set for maximum hold until the amplitude
stabilizes.

\(3\) For transmitters that employ frequency hopping, stepped frequency
or similar modulation types, the peak emission level measurement, the
measurement of the RMS average emission levels, the measurement to
determine the center frequency, and the measurement to determine the
frequency at which the highest level emission occurs shall be made with
the frequency hop or step function active. Gated signals may be measured
with the gating active. The provisions of Section 15.31(c) of this part
continue to apply to transmitters that employ swept frequency
modulation.

\(4\) The ‑10 dB bandwidth is based on measurement using a peak
detector, a 1 MHz resolution bandwidth, and a video bandwidth greater
than or equal to the resolution bandwidth.

\(5\) Alternative measurement procedures may be considered by the
Commission.

6\. Section 15.515 is amended by adding a new paragraph (g), to read as
follows:

Section 15.515 [Technical requirements for vehicular radar
systems]{.underline}.

\* \* \* \* \*

\(g\) The emission levels from devices operating under the provisions of
this section that employ gated transmissions may be measured with the
gating active. Measurements made in this manner shall be repeated over
multiple sweeps with the analyzer set for maximum hold until the
amplitude stabilizes.

7.  Section 15.521 is amended by revising paragraph (d), to read as
    follows:

Section 15.521 [Technical requirements applicable to all UWB
devices]{.underline}.

\* \* \* \* \*

\(d\) Within the tables in Sections 15.509, 15.511, 15.513, 15.515,
15.517, and 15.519, 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. Unless otherwise
stated, 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.

\* \* \* \* \*

**Appendix B**

**Comments and Reply Comments Filed in Response to the**

**Further Notice of Proposed Rule Making**

Comments:

1\. Delphi Automotive Systems Corporation ("Delphi")

2\. James Page

3\. Multispectral Solutions, Inc. ("MSSI")

4\. National Academy of Sciences' Committee on Radio Frequencies
("CORF")

5\. Short Range Automotive Radar Frequency Allocation Group ("SARA")

6\. Siemens VDO Automotive AG ("Siemens VDO")

Reply Comments:

1\. Delphi Automotive Systems Corporation ("Delphi")

2\. James Page

3\. Multispectral Solutions, Inc. ("MSSI")

4\. Northrop Grumman Corporation and Raytheon Company ("Northrop Grumman
and Raytheon")

5\. Satellite Industry Association ("SIA")

6\. Siemens VDO Automotive AG ("Siemens VDO")

7\. XM Radio and Sirius Radio Inc. ("XM and Sirius")

8\. XtremeSpectrum, Inc. ("XSI")

**STATEMENT OF**

**CHAIRMAN MICHAEL K. POWELL**

*Re: Revision of Part 15 of the Commission's Rules Regarding
Ultra-Wideband Transmission Systems*

This Commission has dedicated itself to incubating new technologies like
ultra-wideband. Today we take additional steps to facilitate deployment
of this groundbreaking and paradigm busting technology. Nearly two years
ago we first adopted rules to permit several categories of
ultra-wideband devices to operate under our Part 15 rules for use by
consumers and non-Federal Government entities, including: imaging
systems, vehicular radars, and indoor and outdoor communications
systems.

Today, we amend our Part 15 non-UWB regulations to permit the use of
peak emissions levels, similar to the levels applied to UWB devices.
This will in turn provide greater flexibility for the introduction of
new wide-bandwidth devices and systems. These new devices include radar
systems to improve automotive safety and tracking systems for personnel
location, such as hospital patients and emergency rescue crews, as well
as for functions such as inventory control. Ultimately, this action will
provide greater flexibility in the traditional Part 15 rules to
facilitate the introduction of new equipment designs, a wider variety of
products and increase consumer choices.

[^1]: *See Memorandum Opinion and Order and Further Notice of Proposed
    Rule Making* ("*MO&O*" and "*FNPRM*") in ET Docket No. 98‑153, 18
    FCC Rcd 3857 (2003).

[^2]: *Id*. at para. 1, 29, 33, 54, and 169. We are, however,
    instituting a minor change to the rules applicable to UWB vehicular
    radar systems. This change will conform the measurement procedures
    used for both UWB radars to the provisions for non-UWB radars being
    adopted in this order.

[^3]: *See First Report and Order* in ET Docket No. 98-153, 17 FCC Rcd
    7435 (2002). An *Erratum* to the *First Report and Order* was
    adopted on May 30, 2002. *See Erratum* in ET Docket No. 98-153, 17
    FCC Rcd 10505 (2002). *See*, also, *Order* in ET Docket No. 98-153,
    17 FCC Rcd 13522 (2002), adopted July 12, 2002, regarding who may
    operate a ground penetrating radar ("GPR") and for what purpose. A
    petition for reconsideration filed by Multispectral Solutions, Inc.
    ("MSSI") was dismissed under delegated authority of the Chief,
    Office of Engineering and Technology, by letter dated August 4,
    2003. The MSSI petition was found to be repetitious, addressing
    issues that had already been considered by the Commission and
    containing no new information or arguments. Further, the changes
    sought by MSSI were proposed in the *FNPRM* and, consequently, are
    being addressed in this instant proceeding without the need for
    reconsideration of the *MO&O*.

[^4]: In order to be classified as UWB, the emission, at any point in
    time, must have a fractional bandwidth of at least 0.20 or a -10 dB
    bandwidth of at least 500 MHz. *See* 47 C.F.R. §15.501(d).

[^5]: The rules adopted in the *1^st^ R&O* also permit UWB devices to
    comply with the minimum bandwidth requirement by use of a high speed
    data rate or other modulation techniques instead of the width of the
    pulse or impulse signal.

[^6]: Typical pulse widths used by UWB devices currently are on the
    order of 0.1-2 nanoseconds, or less, in width. The emission spectrum
    of these devices 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.

[^7]: Imaging systems consist of GPRs, wall imaging systems,
    through-wall imaging systems, surveillance systems, and medical
    imaging systems.

[^8]: The operation of Government radio stations is regulated by the
    National Telecommunications and Information Administration (NTIA),
    while operation of stations by private industry, by state and local
    governments and by the public is regulated by the FCC.

[^9]: *See* 47 C.F.R. § 15.205. The restricted bands are frequency bands
    employed for safety of life applications and for use by radio
    services that must function, as a nature or their operation, using
    extremely low received signal levels. The latter systems may be
    passive, such as radio astronomy, or active, such as satellite down
    links and wildlife tracking systems. Unlicensed devices generally
    are not allowed to operate in these bands.

[^10]: *See* 47 C.F.R. § 15.35(b).

[^11]: There is sufficient spectrum between restricted bands to allow
    for the operation of non-UWB devices without having to permit such
    devices to operate in the restricted frequency bands. *See 1^st^
    R&O*, *supra*, at para. 30‑32 for additional discussion on this
    issue.

[^12]: While 47 C.F.R. § 15.35(b) specifies that a minimum 1 MHz
    resolution bandwidth is employed for emission measurements above
    1000 MHz, when pulse widths are narrower than the inverse of the
    resolution bandwidth employed by a spectrum analyzer it is necessary
    to apply a pulse desensitization correction factor ("PDCF") to the
    peak level measured on the spectrum analyzer in order to compensate
    for the analyzer's inability to respond fast enough to reflect the
    true peak power, *i.e.*, the spectrum analyzer does not have
    sufficient bandwidth to measure all of the energy in the pulsed
    signal.

[^13]: *See 1^st^ R&O*, *supra*, at para. 214-220 for additional
    discussion on this issue.

[^14]: 47 C.F.R. §§ 15.509(f), 15.510(d)(5). 15.511(e), 15.513(f),
    15.515(f), 15.517(e), and 15.519(e). *See*, also, 47 C.F.R. §
    15.521(g) for measurements employing a bandwidth narrower than 50
    MHz. There is no requirement for equipment operating below 960 MHz
    to measure peak emission levels since emissions below that frequency
    are based on measurements employing a quasi-peak detector function.
    There also is no requirement to apply a pulse desensitization
    correction factor to the peak measurement since the total peak power
    is not being measured.

[^15]: These analyses and tests have been filed in the record for this
    proceeding. *See*, for example, NTIA Special Publication 01-43,
    *Assessment of Compatibility between Ultrawideband Devices and
    Selected Federal Systems*, January 2001; NTIA Special Publication
    01-45, *Assessment of Compatibility between Ultrawideband (UWB)
    Systems and Global Positioning System (GPS) Receivers*, February
    2001; NTIA Special Publication 01-47, *Assessment of Compatibility
    between Ultrawideband (UWB) Systems and Global Positioning System
    (GPS) Receivers (Report Adendum)*, November 2001; NTIA Report
    01-383, *The Temporal and Special Characteristics of Ultrawideband
    Signals*, January 2001; NTIA Report 01-384, *Measurements to
    Determine Potential Interference to GPS Receivers from Ultrawideband
    Transmission Systems*, February 2001; NTIA Report 01-389, *Addendum
    to NTIA Report 01-384: Measurements to Determine Potential
    Interference to GPS Receivers from Ultrawideband Transmission
    Systems*, September 2001; *Final Report UWB-GPS Compatibility
    Analysis Project*, 8 March 2001, Strategic Systems Department, The
    Johns Hopkins University/Applied Physics Laboratory; the study
    submitted by NTIA on March 21, 2001, on behalf of the Department of
    Transportation regarding tests performed at Stanford University; *A
    Model for Calculating the Effect of UWB Interference on a CDMA PCS
    System*, September 12, 2000, Dr. Jay Padgett, Senior Research
    Scientist, Telcordia Technologies attached to the Sprint comments of
    September 12, 2000; measurements and analysis submitted by Qualcomm
    in its comments of March 5, 2001; the analyses submitted by the
    Satellite Industry Association in several of its comments; and
    multiple others.

[^16]: 47 C.F.R. § 15.519. Imaging systems consist of ground penetrating
    radars (GPRs) and wall imaging systems under 47 C.F.R. § 15.509,
    through-wall imaging systems under 47 C.F.R. § 15.510, surveillance
    systems under 47 C.F.R. § 15.511, medical imaging systems under 47
    C.F.R. § 15.513, and vehicular radar systems under 47 C.F.R. §
    15.515.

[^17]: 47 C.F.R. 15.503(d).

[^18]: Siemens VDO, Delphi, MS Sedco, M/A-COM and SARA filed *ex parte*
    comments to the *FNPRM*. Siemens VDO and Delphi also filed *ex
    parte* comments in response to the submission from NTIA.

[^19]: XSI filed *ex parte* comments in response to Cingular's reply
    comments.

[^20]: This letter was filed in the time frame for reply comments to
    SIA's petition.

[^21]: 47 C.F.R. §§ 15.517-15.519.

[^22]: MSSI Petition for Reconsideration of the *1^st^ R&O* at pg.
    10-11. MSSI specifically mentioned vehicular radar systems as an
    example of such equipment. MSSI defined a low PRF as being less than
    100 kpps.

[^23]: 47 C.F.R. § 15.519.

[^24]: The current UWB regulations do not contain a limit on PRF nor do
    they restrict the type of modulation provided that the UWB emitter,
    at any point in time, has a fractional bandwidth of at least 0.20 or
    a ‑10 dB bandwidth of at least 500 MHz. *See* 47 C.F.R. § 15.503(a),
    (c) and (d).

[^25]: 47 C.F.R. § 15.205. MSSI comments of 7/21/03at pg. 1-2.

[^26]: The PDCF is a technique used to determine the true pulse
    amplitude based on measurements taken from a spectrum analyzer. If
    the pulse width is narrower than the inverse of the resolution
    bandwidth, the analyzer does not use sufficient bandwidth to measure
    all of the energy in the pulsed signal. Thus, when narrow pulses are
    employed it may be necessary to apply a PDCF to obtain the total
    peak emission level. The level obtained from the spectrum analyzer
    measurement of the peak emission can be considerably increased by
    the addition of the PDCF to obtain the true peak emission level.

[^27]: *UWB Parameters for EMC Coexistance* \[sic\] *with Legacy
    Systems*, Final Report, 31 June 2003, Defense Advanced Research
    Projects Agency ("DARPA"), NETEX Program.

[^28]: MSSI reply comments of 7/25/03at pg. 1-2.

[^29]: The tagging systems described by MSSI employ a transmitter
    incorporated into a "tag" that can be attached to persons or objects
    for tracking purposes.

[^30]: SARA comments of 7/21/03 at pg. 2-3.

[^31]: Delphi comments of 7/18/03at pg. 1-5: reply comments of 8/20/03
    at pg. 1-2.

[^32]: SIA reply comments of 8/20/03 at pg. 1-3.

[^33]: *Id*. at pg. 4. It should be noted that a PDCF is not required to
    be used in the measurement of peak power from UWB devices since the
    peak power is based on the peak power density over a 50 MHz
    bandwidth and not on the total peak power produced by a UWB device.

[^34]: XM and Sirius reply comments of 8/20/03 at pg. 1, 7-8.

[^35]: James Page comments of 7/18/03 at pg. 1 and reply comments of
    7/30/03 at pg. 1.

[^36]: NTIA comments of 1/15/04 at pg. iv and 4-5.

[^37]: Conversely, high PRF systems would be limited by the average
    limit established under the rules and not by the peak limit.

[^38]: *UWB Parameters for EMC Coexistance* \[sic\] *with Legacy
    Systems*, *supra*, at pg. 20. The DARPA study also concluded that
    high PRF, non-dithered systems have a reduced potential for causing
    interference due to the lower probability that a spectral line will
    appear in the passband of the victim receiver but found that
    interference could occur if the spectral line did appear in the
    receiver passband more than one percent of the time.

[^39]: NTIA comments of 1/15/04 at pg. A-4, A-6, A-8, and B-3.

[^40]: 47 C.F.R. § 15.519(a)(1).

[^41]: For example, amending the rules to permit the UWB devices
    operating in the 3.1-10.6 GHz band to be use for vehicular radar
    systems, as requested by MSSI, could result in tens of millions of
    new UWB transmitters emitting outdoors.

[^42]: 47 C.F.R. § 15.35(a) and (b).

[^43]: 47 C.F.R. § 15.35(b).

[^44]: For example, a wideband device that occupies a 1 GHz bandwidth
    with emissions that appear as Gaussian noise is permitted to operate
    at an average limit of --41.3 dBm/MHz which is equivalent to an
    average limit of ‑11.3 dBm/GHz; however, the transmitter also must
    comply with a total peak limit of --21.3 dBm. Thus, its average
    emission level may comply with the standards even though the average
    emission level exceeds the limit on peak emissions.

[^45]: *1^st^ R&O*, *supra*, at para. 214.

[^46]: In order to accurately measure a peak signal, the video bandwidth
    must not be less than the RBW. Ideally, the video bandwidth should
    be at least 3 times the RBW.

[^47]: While some types of emissions have a peak-to-average level that
    changes based on 10 log (RBW/50), others change at a rate of 20 log
    (RBW/50). The use of the (20 log) formula ensures that the peak
    level will not exceed the actual UWB standard, 0 dBm in a 50 MHz
    bandwidth, regardless of the type of modulation employed.

[^48]: A field strength limit of 5000 uV/m, as measured at 3 meters, is
    equivalent to an EIRP of --21.3 dBm.

[^49]: Delphi comments of 7/18/03 at pg. 2 and 7; Siemens VDO comments
    of 7/21/03 at pg. 15-16.

[^50]: In other words, systems employing a bandwidth of less than 50 MHz
    would be required to operate at a peak power level that is reduced
    below 0 dBm by an amount that is dependent on the actual emitted
    bandwidth.

[^51]: Siemens VDO comments of 7/21/03 at pg. 28-30. Siemens VDO
    conditions this statement on the specific case where the PRF is
    equal to or greater than the RBW, referencing NTIA Report 01-383,
    *supra*, at figure 8.86 on pg. 8-46 through 8-48.

[^52]: James Page comments of 7/18/03 at pg. 1.

[^53]: Delphi comments of 7/18/03 at pg. 7-8; Delphi reply comments at
    pg. 3.

[^54]: NTIA comments of 1/15/04 at pg. 6-13 and at Appendices A and B.

[^55]: MSSI comments of 7/2103 at pg. 1-2. MSSI also has obtained
    certification for an indoor-only UWB tracking system operating in
    the 5751-7001 MHz band.

[^56]: Delphi comments of 7/18/03 at pg. 2-5. While the levels of the
    emissions from high-PRF systems would be constrained based on our
    average emission limits under the standards adopted for UWB devices,
    the current non-UWB peak limit prevents such systems from being
    employed.

[^57]: Delphi *ex parte* comments of 4/13/04 at pg. 2.

[^58]: EESS passive receivers were cited by NTIA as an exception to this
    specification.

[^59]: The examples provided by MSSI demonstrating no harmful
    interference from low PRF UWB devices were based on receivers
    incorporating signal processing techniques, such as GPS receivers
    and U.S. Government receivers used in defense applications.

[^60]: Operation in this frequency band currently is permitted under the
    Part 15 general emission limits in 47 C.F.R. § 15.209.

[^61]: This, of course, requires that the peak emission levels be low
    enough that the front ends of the receivers are not saturated.

[^62]: We believe that the satellite systems operating in the 17.3-17.7
    GHz band will employ sufficient signal processing techniques to
    demonstrate some immunity to increased peak signal levels.

[^63]: 47 C.F.R. § 15.205.

[^64]: 47 C.F.R. § 15.209. The maximum specified emission limit in these
    frequency bands is 500 uV/m, as measured at 3 meters using a 1 MHz
    resolution bandwidth. This field strength level is equivalent to an
    EIRP of ‑41.25 dBm/MHz.

[^65]: Emissions above 960 MHz from UWB devices are based on the use of
    an RMS average. Emissions above 1000 MHz from non-UWB devices are
    based on a linear average. As previously indicated by NTIA, RMS
    levels are proportional to the measurement bandwidth and the
    spectral power density, irrespective of pulse rate or modulation.
    *See* NTIA Report 01-383, *supra*, at pg. 8-44. Agilent also states
    that an RMS detector reports the true average power for each part of
    the measurement span which is particularly useful when measuring
    non-continuous waveforms such as those produced by frequency
    switching or packet based transmissions. Agilent adds that the RMS
    average detector is well behaved when measuring noise-like signals.
    *See* Agilent APP Note 1488, *Ultra-Wideband Communication RF
    Measurements*, at pg. 43. We also observe that measurements made on
    the same equipment using an RMS detector generally may be slightly
    higher than similar measurements obtained using a linear detector,
    particularly for noise-like emissions. Thus, the requirement to use
    an RMS detector can be a more stringent specification than emission
    limits based on the use of a linear average detector.

[^66]: 47 C.F.R. §§ 15.515 and 15.519. These comments from NTIA were
    stated verbally to the Commission's staff on December 2, 2004, and
    on subsequent dates. We do not believe that such stringent limits
    are necessary to prevent harmful interference. The emission levels
    requested by NTIA are extremely conservative, being based on
    multiple worst case conditions at detection levels below what may be
    considered harmful interference. Further, as stated in the *1^st^
    R&O*, the analyses and standards applied to UWB are unique to that
    proceeding and will not be considered as a basis for determining or
    revising standards for other radio frequency devices, including
    other Part 15 devices.

[^67]: As described above, we also are adopting the same peak emission
    limit that applies to UWB operations.

[^68]: Normally, transmission systems operating under the general
    emission limits are not required to reduce their emissions below the
    limits specified in 47 C.F.R. § 15.209, and instead are subject to a
    requirement that the spurious emissions not exceed the level of the
    fundamental emission. *See* 47 C.F.R. § 15.209(c). The requirement
    in 47 C.F.R. § 15.215(c) to attenuate emissions outside of the
    operating band by at least 20 dB was established for transmitters
    that operate at signal levels greater than those specified in 47
    C.F.R. § 15.209.

[^69]: 47 C.F.R. § 15.209.

[^70]: 47 C.F.R. § 15.109.

[^71]: We believe that emissions appearing within the frequency bands
    below 3.1 GHz, which are of particular concern to NTIA, will consist
    solely of emissions from digital circuitry and, thus, will be
    subject to the standards in 47 C.F.R. § 15.209. For this reason, the
    more stringent limits requested by NTIA should have a minimal impact
    on equipment designed to operate under these provisions.

[^72]: Devices that operate with an emission bandwidth in excess of 500
    MHz would not be required to operate under the UWB regulations but
    may operate under the provisions being adopted herein. Separate
    standards were implemented for UWB devices because these extremely
    wideband devices, by necessity, must operate within the restricted
    frequency bands. That is not the case here. The parameters for
    wideband operation are being designed only for use within frequency
    bands where unlicensed non-UWB Part 15 operation currently is
    permitted.

[^73]: Frequency hopping, stepped frequency and gated transmissions have
    relatively similar interference profiles. The interference potential
    for swept frequency has not been evaluated nor have measurement
    procedures been proposed in this proceeding.

[^74]: NTIA comments of 1/15/04 at pg. 5.

[^75]: Operation in the 16.2-17.7 GHz band is limited to field
    disturbance sensors that are used only on terrestrial transportation
    vehicles for back-up assistance. Terrestrial use is limited to earth
    surface-based, non-aviation applications. Thus, there is no need to
    prohibit the use of fixed infrastructures.

[^76]: *See* NTIA Report 01-383, *supra*, at figure 8.86 on pg. 8-46
    through 8-48. This report states that the peak relationship follows
    a 20 log ratio when the RBW is much greater than the PRF and that
    the non-dithered average and the peak signal levels are equal when
    the RBW is much lower than the PRF, *i.e.*, when the output level of
    the system would be constrained by our limit on average emission
    levels, not by our limit on peak emission levels. For a non-dithered
    UWB emission, when RBW is much lower than the PRF the emissions
    appear to be discrete CW lines and further reductions in the RBW do
    not result in any change to the measured values. Dithered peak
    emissions follow a 10 log ratio only when the RBW is much less than
    the PRF. Thus, the maximum 6 dB "error" cited by Siemens VDO occurs
    only when the RBW is much lower than the PRF and the UWB impulses
    are dithered. The situation where RBW and PRF are approximately
    equal, as cited by Siemens VDO, represents a transition region
    between a Gaussian probabilistic region and a deterministic
    impulsive environment and does not follow a precise mathematical
    model. In *Assessment of Compatibility between Ultrawideband Devices
    and Selected Federal Systems*, NTIA Special Publication 0-43,
    January 2001, at pg. D-1 and D-2, NTIA employed a 10 log ratio to
    represent the peak power in a 50 MHz bandwidth when RBW is less than
    or equal to 0.45 PRF (non-dithered) and when RBW is less than or
    equal to 2.0 PRF (dithered).

[^77]: 47 C.F.R. § 15.515. Non-UWB vehicular radar systems are permitted
    to operate under 47 C.F.R. § 15.245 in the 24.075-24.175 GHz band,
    under 47 C.F.R. § 15.249 in the 24.0-24.25 GHz band, or under 47
    C.F.R. § 15.209 in the 24.0-31.2 GHz band.

[^78]: 47 C.F.R. § 15.503 defines a UWB transmitter as an intentional
    radiator that, at any point in time, has a fractional bandwidth
    equal to or greater than 0.2 or has a UWB bandwidth equal to or
    greater than 500 MHz, regardless of the fractional bandwidth.

[^79]: 47 C.F.R. § 15.205. *See*, also, *1^st^ R&O*, *supra*, at para.
    30-32. As noted by the Commission, there are sufficient spaces
    between the restricted bands to permit the operation of Part 15
    systems employing bandwidths narrower than 500 MHz. Accordingly,
    unlike UWB devices, there is no necessity to permit narrowband
    systems to operate in the restricted bands.

[^80]: *See 1^st^ R&O*, *supra*, at para. 32 and *MO&O*, *supra*, at
    para. 45 and 48. *See*, also, 47 C.F.R. § 15.31(c).

[^81]: The Commission expressed similar concerns in the *Notice of
    Proposed Rule Making* ("*Notice*") in this proceeding, and declined
    to include transmitters employing swept frequency and similar
    modulation types from consideration as UWB devices. *See Notice of
    Proposed Rule Making* in ET Docket No. 98-153, 65 Fed. Reg. 37332,
    June 14, 2000, at para. 21.

[^82]: Siemens VDO Petition for Reconsideration of the *1^st^ R&O* at
    pg. 5-6.

[^83]: *Id.* at pg. 6-8. Also, *1^st^ R&O*, *supra*, at para. 32 and 47
    C.F.R. § 15.31(c).

[^84]: *Id.* at pg. 4 and 8-10. The "averaging time" actually refers to
    the integration period employed by each sampling bin in a spectrum
    analyzer. For a 1 ms averaging period, the sweep time divided by the
    number of bins must be less than 1 millisecond, *i.e.*, if the
    analyzer employs 601 bins, the minimum sweep time is 601
    milliseconds.

[^85]: *Id.* at pg. 10-11.

[^86]: *Id.* at pg. 13-14. It should be noted that there is a wide range
    of integration times possible for space borne passive sensors. For
    example, the AMSR sensor has a 2.6 millisecond integration time in
    the 23.6-24.0 GHz band. However, the AMSU-A sensor has an
    integration time of 158-165 milliseconds.

[^87]: *See MO&O*, *supra*, at para. 48.

[^88]: A waiver was issued to Siemens VDO on June 25, 2003, by letter
    under delegated authority of the Chief, Office of Engineering and
    Technology. That waiver, based on an agreement between NTIA and
    Siemens VDO, specified operation under different technical standards
    than those requested by Siemens VDO in its petition for
    reconsideration of the *1^st^ R&O* and from those proposed by the
    Commission in the *FNPRM*. For example, the waiver limits the
    emissions from the Siemens vehicular radar transmitter to a -34 dBm
    peak EIRP limit and to a ‑61.3 dBm RMS average EIRP limit in the
    23.6-24.0 GHz band with lower emission levels permitted for
    elevation angles above 30 degrees, bases RMS average emission limits
    on a one millisecond integration period, and includes a requirement
    that the -10 dB bandwidth be contained within the 24‑29 GHz
    frequency band with the center frequency located above 24.075 GHz.
    NTIA also specified the measurement procedures that would be used to
    determine the bandwidth and emission levels.

[^89]: As noted in para. 32 of the *1^st^ R&O*, *supra*, the emissions
    from transmitters employing frequency hopping modulation are
    measured with the frequency hop stopped. *See* 47 C.F.R. § 15.31(c).
    While this regulation specifically addresses swept frequency
    devices, having been established prior to frequency hopping systems
    being permitted under the regulations, it also has been applied to
    frequency hopping systems. *See* Public Notice of March 30, 2000,
    *Filing and Measurement Guidelines for Frequency Hopping Spread
    Spectrum Systems*, DA 00-705. At the time of the *1^st^ R&O*, no
    other measurement procedures had been proposed or established for
    frequency hopping systems.

[^90]: At any point in time, there would be fewer hopping channel radars
    transmitting on the same frequency, but there would be a higher
    output level from these devices. Our concern for interference to
    terrestrial services is based on nearby vehicular radars rather than
    a general cumulative impact.

[^91]: The Commission also proposed to eliminate the minimum UWB
    bandwidth standards which could make this issue moot.

[^92]: Siemens VDO Petition for Reconsideration of the *1^st^ R&O* at
    Appendix A, pg. 16-17. These measurement procedures were
    incorporated by reference into the *FNPRM*.

[^93]: Siemens VDO comments of 7/21/03 at pg. 3.

[^94]: *Id*. at pg. 7-8.

[^95]: *Id*. at pg. 10-11.

[^96]: *Id*. at pg. 8-11.

[^97]: *Id*. at pg. 6.

[^98]: *Id*. at pg. 11-12.

[^99]: *Id*. at pg. 12-13.

[^100]: *Id*. at pg. 13-15 and the attachment to these comments
    summarizing the Cetecom interference study.

[^101]: *Id*. at pg. 16-27.

[^102]: *Measurements of Siemens Pulsed Frequency Hopping Vehicular
    Radar Prototype*, NTIA, March 20, 2003, at pg. 37, as cited in
    Siemens VDO comments of 7/21/03 at pg. 25. This report exists in
    draft form only and has not been released by NTIA. Neither Siemens
    VDO nor NTIA has submitted this test report into the record for this
    proceeding.

[^103]: SARA comments of 7/21/03 at pg. 4.

[^104]: CORF comments of 7/16/03 at pg. 1.

[^105]: *Id*. at pg. 2-3.

[^106]: *Id*. at pg. 5-6.

[^107]: *Id*. at pg. 7.

[^108]: *Id*.

[^109]: Northrop Grumman and Raytheon reply comments of 8/20/03 at pg.
    1.

[^110]: *Id*. at pg. 5-6.

[^111]: Siemens VDO reply comments of 8/20/03 at pg. 3.

[^112]: *Id*. at pg. 4.

[^113]: *Id*.

[^114]: *Id*. at pg. 5.

[^115]: These comments were stated verbally to the Commission's staff on
    December 2, 2004, and on subsequent dates. These comments replace
    the 1/15/04 comments NTIA filed formally in this proceeding
    indicating that interference impact to EESS passive receivers from
    frequency hopped pulsed radar systems is comparable to that of
    impulse radars operating under the current UWB regulations.

[^116]: NTIA comments of 1/15/04 at pg. 13-19.

[^117]: 47 C.F.R. § 15.205.

[^118]: 47 C.F.R. §§ 15.503(d).

[^119]: *1^st^ R&O*, *supra*, at para. 30-31.

[^120]: *1^st^ R&O*, *supra*, at para. 32.

[^121]: In performing a peak measurement, there is no need to stop the
    hopping function as long as the measurement is taken for a
    sufficiently long time period to ensure that all of the energy that
    will appear in that frequency band is measured.

[^122]: 47 C.F.R. § 15.515. As with the emission standards for operation
    in the 6 GHz and 17 GHz band, we do not believe that such stringent
    limits are necessary to prevent harmful interference. The emission
    levels requested by NTIA are extremely conservative, being based on
    multiple worst case conditions at detection levels below what may be
    considered harmful interference. Further, as stated in the *1^st^
    R&O*, the analyses and standards applied to UWB are unique to that
    proceeding and will not be considered as a basis for determining or
    revising standards for other radio frequency devices, including
    other Part 15 devices.

[^123]: Normally, transmission systems operating under the general
    emission limits are not required to reduce their emissions below the
    limits specified in 47 C.F.R. § 15.209, and instead are subject to a
    requirement that the spurious emissions not exceed the level of the
    fundamental emission. *See* 47 C.F.R. § 15.209(c).

[^124]: 47 C.F.R. § 15.209. As with transmisison systems operating in
    the 6 and 17 GHz bands being implemented in this order, we believe
    that emissions appearing within the frequency bands below 3.1 GHz,
    which are of particular concern to NTIA, will consist solely of
    emissions from digital circuitry and, thus, will be subject to the
    standards in 47 C.F.R. § 15.209. For this reason, the more stringent
    limits requested by NTIA should have a minimal impact on equipment
    designed to operate under these provisions.

[^125]: 47 C.F.R. § 15.109.

[^126]: *1^st^ R&O*, *supra*, at para. 32.

[^127]: While Siemens VDO makes reference to a study demonstrating that
    there is no interference to Amateur and radar applications under
    "real" road conditions, Siemens VDO does not provide a copy of this
    study nor does it describe the "real" road conditions it indicates
    are necessary to demonstrate a lack of interference. We are unable
    to determine whether this study addresses interference based on the
    instantaneous vehicular radar emission levels or the time averaged
    levels nor can we determine the emission levels and other modulation
    characteristics that were employed for the vehicular radar. In
    particular, we have no information to demonstrate whether the victim
    receivers are sensitive to potential interference from the
    instantaneous vehicular radar emission levels or from the
    time-averaged levels. CORF and Northrop Grumman and Raytheon
    continue to argue against allowing devices to operate in the 22-24
    GHz band, but these comments are akin to late filed petitions for
    reconsideration of the decisions made in the *1^st^ R&O* and present
    no new information to justify changes to the Commission's earlier
    decisions.

[^128]: EESS receivers are satellite receivers located orbiting the
    earth and, obviously, are not ground-based.

[^129]: As an example, depending on the averaging time of the measuring
    instrument and the hopping rate a frequency hopping system employing
    50 hopping channels could, through time averaging of the emission
    levels, increase its signal level by as much as 17 dB above the
    average limit.

[^130]: With a 1 millisecond averaging period, any hopping rate in
    excess of 1 kHz could permit a higher instantaneous average signal
    level on the individual hopping channels. With a 10 milliseconds
    averaging period, a higher instantaneous signal level could occur
    for any hopping rate in excess of 100 Hz. However, any increase in
    the instantaneous average level also could be limited by the peak
    UWB emission limit.

[^131]: Gating refers to the transmitter's emission being turned on and
    off.

[^132]: SARA and M/A-COM, in their *ex parte* filings, requested that
    UWB vehicular radar systems operating in the 22-29 GHz band be
    tested with the gating active.

[^133]: The requirement to measure gated UWB transmitters with the
    gating disabled is contained in 47 C.F.R. § 15.521(d).

[^134]: The requirement to stop the frequency hopping or step function
    is contained in the UWB measurement procedures, as stated in the
    *1^st^ R&O*, *supra*, at para. 32.

[^135]: Under the conditions of its waiver, Siemens VDO vehicular radars
    had to operate in the 24-29 GHz band.

[^136]: Delphi Comments of 7/18/03 at pg. 8.

[^137]: MSSI Petition for Reconsideration of 6/14/2002 at pg. 9.

[^138]: MSSI comments of 7/21/03 at pg. 1-2.

[^139]: For a Fourier line spectrum, *i.e.*, where the resolution
    bandwidth (RBW) is less than 0.3 times the pulse repetition
    frequency (PRF), the pulse desensitization factor is equal to 20 log
    \[(effective pulse width)(PRF)\] dB.

[^140]: 47 C.F.R. § 15.31(a). *See*, also, *American National Standard
    for Methods of Measurement of Radio-Noise Emissions from Low-Voltage
    Electrical and Electronic Equipment in the Range of 9 kHz to 40
    GHz*, ANSI C63.4-1992, at pg. 62 and 90. This measurement procedure
    specified that HP Application Note 150-2 should be employed to
    determine the PDCF, as necessary. *See* Hewlett-Packard Co.
    Application Note 150-2, *Spectrum Analysis -- Pulsed RF*, November
    1971.

[^141]: *See* *Second Report and Order and Memorandum Opinion and Order*
    in ET Docket No. 01-278, 18 FCC Rcd 14741 (2003). The Commission
    recently amended its regulations to reference ANSI C63.4-2003. *See
    Report and Order* in ET Docket 03-201, 19 FCC Rcd 13539 (2004). ANSI
    C63.4-2003 has the same text regarding PDCF that was contained in
    ANSI 63.4-2001.

[^142]: MSSI Petition for Reconsideration of 6/14/02 at pg. 2-9.

[^143]: *MO&O*, *supra*, at para. 146.

[^144]: *Notice of Inquiry* in ET Docket No. 98-153, 13 FCC Rcd 16376
    (1998), at para. 5 and 13; *Notice of Proposed Rule Making* in ET
    Docket No. 98-153, 15 FCC Rcd 16376 (2000), at para. 4, 35, 48, 51
    and 53; *1^st^ R&O*, *supra*, at para. 8 and 236; *MO&O*, *supra*,
    at para. 143-146. As previously explained by the Commission, the
    requirement to apply a PDCF is not contained in Section 15.35(b) of
    the rules. Rather, this requirement is specified in HP Application
    Note 150-2, *supra*, which contains the instructions on how to
    measure pulsed emissions using a spectrum analyzer. *See* 47 C.F.R.
    §§ 15.31(a)(3) and 15.35(b).

[^145]: On frequencies where the emission limit is based on the use of a
    quasi-peak detector, there is no requirement to apply a peak
    emission limit and, consequently, no requirement to apply a PDCF.

[^146]: MSSI comment of 7/21/03, at Attachment 6.

[^147]: MSSI Request for Immediate Clarification of Section 15.35(b),
    February 12, 2003, at pg. 2 and 5, attached to MSSI comment of
    7/21/03.

[^148]: The fractional bandwidth, as defined in 47 C.F.R. § 15.503(c),
    is equal to the -10 dB bandwidth of the emission divided by the
    center frequency. In simple terms, a fractional bandwidth of 0.20
    means that the -10 dB bandwidth is 20 percent of the center
    frequency.

[^149]: It is the limit on emission levels, particularly the limit on
    spectral power density, that primarily controls interference
    potential.

[^150]: Delphi comments of 7/18/03 at pg. 2 and 8; SARA comments of
    7/21/03 at pg. 2-3; Siemens VDO comments of 7/21/03 at pg. 15-22.

[^151]: SIA reply comments of 8/20/03 at pg. 5.

[^152]: XSI reply comments of 8/20/03 at pg. 1-5.

[^153]: NTIA comments of 1/15/04 at pg. 23-25.

[^154]: Delphi comments at pg. 1, 5-6.

[^155]: Northrop Grumman and Raytheon reply comments of 8/20/03 at pg.
    1-2 and 8.

[^156]: The reference to GPRs also includes wall imaging systems. Wall
    imaging systems are the same as a GPR except a GPR is used to look
    down into the ground while a wall imaging system may be used to look
    into a wall or ceiling. The wall or ceiling must be a physical
    structure that is dense enough and thick enough to absorb the
    majority of the signal transmitted by the device. Examples include
    the walls in a mine and concrete structures.

[^157]: A third petition for reconsideration was filed by MSSI. As noted
    earlier, this petition was dismissed under the delegated authority
    of the Chief, Office of Engineering and Technology, by letter dated
    August 4, 2003.

[^158]: XSI filed *ex parte* comments responding to Cingular's response.

[^159]: This letter was filed in the time frame for reply comments to
    SIA's petition.

[^160]: *MO&O*, *surpa*, at para. 55-97.

[^161]: *MO&O*, *supra*, at para. 151. The Commission concluded that the
    statutory argument was a new argument, not contained in Cingular's
    original reconsideration petition and thus constituted a new
    petition that was untimely filed under Section 1.106(f) of our
    rules. The Commission also noted that, even if the filing could be
    considered a supplement to the original petition, Cingular did not
    file a motion for leave to accept the late-filed pleading as
    required by Section 1.106(f) of our rules nor serve the pleading on
    other parties to the proceeding.

[^162]: *See* 47 U.S.C. 301. While Cingular worded its petition to apply
    only to UWB devices, a ruling that Part 15 unlicensed operation is
    in violation of Section 301 of the Act would affect all Part 15
    unlicensed transmission systems and would not be limited to only UWB
    devices.

[^163]: Cingular Petition for Reconsideration of 6/17/02 at pg. 5-7,
    10-14 and 20-21.

[^164]: The Cellular Radiotelephone Service operates at 824-849 MHz and
    869-894 MHz; PCS operates at 1850‑1910 MHz and 1930-1990 MHz; and
    GPS operates at 1164-1240 MHz and 1559-1610 MHz. The actual GPS
    frequencies are 1575.42 [+]{.underline} 12 MHz for the L1 band,
    1227.60 [+]{.underline} 12 MHz for the L2 band, and 1176.45
    [+]{.underline} 12 MHz for the L5 band.

[^165]: Cingular Petition for Reconsideration of 6/17/02 at pg. 7,
    14-20, and 21-24.

[^166]: 47 U.S.C. § 301; *see also* Cingular Petition for
    Reconsideration of 5/22/03 (citing the Act).

[^167]: 47 U.S.C. § 308(a); *see also* Cingular Petition for
    Reconsideration of 5/22/03 at pg. 10 (citing the Act and discussing
    the submission of an application as a prerequisite to obtaining a
    license under Section 308(a)).

[^168]: Communications Amendments Act of 1982, P.L. 97-259; H.R. Conf.
    Rep. No. 97-765 at 31-32 (1982), reprinted in 1982 U.S.C.C.A.N.
    2261, 2275-76 (citing Fisher's Blend Station, 297 U.S. 650, 655
    (1936)) (discussing Congress' intent that the amendment make Section
    301 consistent with prior judicial decisions finding that all radio
    signals are inherently interstate).

[^169]: 47 U.S.C. § 302a; Cingular reply comments of 9/17/03.

[^170]: Cingular Petition for Reconsideration of 5/22/03 at pg. 12

[^171]: *See* Cingular reply comments of 9/17/03 at pg. 8. Cingular also
    notes that Section 307(e) was added to the Act in 1982, when
    Congress amended Section 301 to clarify the Commission's intrastate
    jurisdiction over radio.

[^172]: *See* XSI comments of 9/4/03 at pg. 14-15. XSI points to three
    legislative actions in support. Enacting Section 302a Congress
    specifically discussed the need for proper regulation of garage door
    openers, a category of Part 15 device; enacting the Electronic
    Communications Privacy Act of 1986, Congress noted that cordless
    telephones operate under Part 15 of the Commission's rules "and are
    not licensed;" Congress instructed the Commission in the Balanced
    Budget Act of 1997 to auction off certain frequency bands which,
    among other criteria, had not then been allocated or authorized for
    unlicensed use pursuant to part 15 of the Commission's regulations
    (47 C.F.R. Part 15). *See* P.L. 90-379, S. Rep. 1276, reprinted at
    1968 U.S. Code Cong. & Admin. News 2486, 2488; 41 P.L. 99-508, H.
    Rep. 99-647, 99th Cong., 2d Sess. at 33 (June 19, 1986); P.L. 105-33
    Section 3002(c)(1)(C)(v), 11 Stat. 261. (1997).

[^173]: *See* Cingular reply comments of 9/17/03 at pg. 8.

[^174]: *See* fn 161 *supra*.

[^175]: Courts have considered the problem raised by last minute
    arguments that are submitted to an agency in ways that may deprive
    the agency of a fair opportunity to consider them, and then see a
    petitioner challenge the agency's failure to consider the arguments
    on appeal. The Court in [MCI Worldcom, Inc. *v*. FCC]{.underline},
    760 F. 3d 760 (D.C. Cir. 2000) considered the Commission's failure
    to respond to a subtle suggestion in a single paragraph in an AT&T
    *ex parte* filed after the comment period had ended. The petitioners
    had challenged the failure to respond on appeal. The Court
    ultimately held that the argument was presented---if barely---to the
    Commission. [*Id*.]{.underline} at 765. But the Court's holding was
    undoubtedly influenced by the fact that the ex parte was "suitably
    filed." *[Id]{.underline}*. Here, the legal arguments by Cingular
    clearly were not suitably filed. Cingular's only defense to its
    action is that another party had raised the same Section 301 issue
    before the Commission. *[See]{.underline}* Cingular Petition for
    Reconsideration of 5/22/03 at pg. 11. However, the party Cingular
    speaks of, ARRL, did not raise the issue in this proceeding. It had
    raised the issue in another proceeding, but has since abandoned the
    argument. *See*, *Amendment of Part 15 of the Commission's Rules to
    allow certification of equipment in the 24.05-24.25 GHz band at
    field strengths up to 2500 mV/m*, ET Docket No. 98-156, *Memorandum
    Opinion and Order*, 18 FCC Rcd 15, 944 (2003).

[^176]: 47 C.F.R. § 1.429(d)(i).

[^177]: *See Hernstadt v. FCC*, 677 F.2d 893, 902 n.22 (D.C. Cir. 1980)
    (Congress presumed to be cognizant of and legislate against
    background of existing agency interpretation of law); *Sweet Home v.
    Babbitt*, 17 F.3d 1463, 1471 (D.C. Cir. 1994) (same), *rev'd on
    other grounds*, 55 U.S. 687 (1995).

[^178]: Section 301 imposes a licensing requirement on a person who uses
    or operates "any apparatus for the transmission of energy or
    communications or signals by radio." 47 U.S.C. § 301.

[^179]: The Commission issued in August 1938 a notice for an informal
    conference with the Chief Engineer on proposed rules and regulations
    for low power radiofrequency devices, which it described as those,
    primarily used by the public, that use radiofrequency current as
    essential to their operation (*e.g*., radio control devices, record
    players) and that may cause interference to radio communications.
    Following a hearing held in September 1938 with various companies
    and associations representing both low power radiofrequency devices
    and radio communications services (*e.g*., National Association of
    Broadcasters, Philco Radio and Television Corp, AT&T, Electro
    Medical Equipment Manufacturers, Westinghouse Electric Co.), the
    Commission issued a press release on November 21, 1938 (No. 30678)
    announcing the adoption of rules and regulations for low power
    radiofrequency electrical devices. The Commission decided that if a
    low power device did not exceed the adopted field strength limit and
    did not cause interference to radio reception, the device would not
    have to be licensed. The original rules also provided that the
    Commission would inspect and test devices to determine whether they
    met the adopted field strength limits and issue a certificate
    specifying conditions of operations to any party making such a
    request. As the number of radiofrequency devices has increased,
    technical knowledge has expanded, and measurement procedures have
    improved, the Commission has modified the rules for the operation of
    unlicensed operations over the years, including an equipment
    approval program. The rule modifications over time in Part 15 have
    had the consistent goals of protecting licensed operator rights and
    benefits, and protecting the licensees themselves from any harmful
    interference. At the same time the rules promote benefits to the
    mass consumer market through the availability of desirable and
    affordable low power radiating devices of many types, used in daily
    life, that can best be provided on an unlicensed (but not on an
    unregulated) basis.

[^180]: *Id.*

[^181]: 47 C.F.R. § 15.3 defines three classes of radio frequency
    emitters as follows:

    > \(n\) Incidental radiator. A device that generates radio frequency
    > energy during the course of its operation although the device is
    > not intentionally designed to generate or emit radio frequency
    > energy. Examples of incidental radiators are dc motors, mechanical
    > light switches, etc.
    >
    > \(o\) Intentional radiator. A device that intentionally generates
    > and emits radio frequency energy by radiation or induction.
    >
    > \(z\) Unintentional radiator. A device that intentionally
    > generates radio frequency energy for use within the device, or
    > that sends radio frequency signals by conduction to associated
    > equipment via connecting wiring, but which is not intended to emit
    > RF energy by radiation or induction.

[^182]: 47 U.S.C. § 151.

[^183]: The Commission recognized in 1938 that many different kinds of
    devices produced electromagnetic or induction fields at radio
    frequencies, even if they did not employ radio frequency current or
    the fields generated as essential to the functioning or purpose of
    the device's operation (*e.g*., switch contacts, automobile
    ignitions, diathermy machines, induction furnaces, oscillators in
    certain radio receivers). *See supra* footnote 179. Today, the use
    of unlicensed devices has become pervasive. For example, the
    Consumer Electronics Association estimates that there is an
    installed base of more than 348.23 million Part 15 consumer
    electronic devices. That is more than one for every US citizen.
    *See* OSP Working Paper Series Number 39, *Unlicensed and
    Unshackled: A Joint OSP-OET White Paper on Unlicensed Devices and
    Their Regulatory Issues*, May 2003, at pg. 22 (this report includes
    additional data on the increase in the use of various unlicensed
    devices, such as cordless telephones, wireless local area networks,
    spread spectrum devices, and WiFi).

[^184]: 47 U.S.C. §§ 301, 303(f).

[^185]: *See* 47 C.F.R. § 15.1(a) (providing that Part 15 sets out the
    regulations under which an intentional, unintentional, or incidental
    radiator may be operated without an individual license); 47 C.F.R. §
    15.1(b) (requiring operation of an intentional or unintentional
    radiator operate in conformity with the regulations of Part 15 or be
    otherwise licensed or exempted).

[^186]: 47 U.S.C. § 301.

[^187]: *See*, *generally*, *In The Matter Of Revision Of Part 15 Of The
    Rules Regarding The Operation Of Radio Frequency Devices Without An
    Individual License*, GEN. Docket No. 87-389, *Report and Order,* FCC
    89-103, 66 Rad. Reg. 2d (P & F) 295 (Apr. 18, 1989) (weighing
    benefits of non-licensed operations and concerns for interference
    potential under Part 15 rules); *Amendment of Part 15 of the
    Commission\'s Rules Governing Restricted Radiation Devices
    Concerning Low Power Communication Devices*, Docket No. 9288,
    *Memorandum Order and Opinion*, FCC 57-1311, 13 RR 1546h, para. 12
    (July 31, 1957) (weighing the adopting of licensing schemes that
    would be infeasible and much more burdensome to the public with the
    Part 15 approach of technical limits and a non-interference
    requirement).

[^188]: In the matter of Modification of Parts 2 and 15 of the
    Commission's Rules for unlicensed devices and equipment approval, ET
    Docket No. 03-201, Report and Order, FCC 04-165 (July 12, 2004); In
    The Matter Of Amendment Of Parts 2, 15, 18 And Other Parts Of The
    Commission\'s Rules To Simplify And Streamline The Equipment
    Authorization Process For Radio Frequency Equipment, ET 97-94,
    Report and Order, FCC 97-84, 12 FCC Rcd. 8743 (Mar 27, 1997);
    Amendment of Part 2 of the Rules to simplify the equipment
    authorization procedures, Gen. Docket No. 82-242, Report and Order,
    FCC 83-3, 48 FR 3614-01 (Jan. 26, 1983).

[^189]: 47 U.S.C. § 302(d)(1).

[^190]: House Report for Federal Communications Commission Authorization
    Act Of 1991, H.R. REP. 102-207, 31 (Sep. 17, 1991) (reporting on
    Pub.L. 102-556, Title IV, § 403(a)). Indeed, one of the primary
    reasons Congress added Section 302 to the Communications Act in 1968
    was to address interference concerns by strengthening the
    Commission's power to impose limits on the manufacture of unlicensed
    Part 15 devices, not by resorting to a formal licensing process to
    control the interference potential of such devices. Thus, Congress
    recognized that compliance by manufacturers and others with the
    Commission's technical rules for unlicensed devices is critical.
    *See* S. Rep. No. 1276, 90th Cong., 2d Sess. 1968, 1968 U.S.C.C.A.N.
    2486 (1968 Senate Report). As a prominent example of the seriousness
    of RFI involving unlicensed devices and the need for additional
    statutory authority for the Commission to strengthen this regulatory
    approach, the Report cited interference caused to air-safety-related
    emergency communications frequencies and homer frequencies at a
    California facility by 58 garage door openers, which were then, as
    well as now, unlicensed devices subject to technical standards in
    Part 15 of our rules. Congress discussed the need for statutory
    change in the legislative history to properly address the increasing
    popularity of such Part 15 regulated devices as garage door openers.
    *Id*. at 2488.

[^191]: 47 U.S.C. § 332(c)(7)(C)(iii).

[^192]: Balanced Budget Act of 1997, P.L. 105-33 Section
    3002(c)(1)(C)(v), 11 Stat. 261 (1997). More specifically, Congress
    excluded these bands from the Section 3002(c) auction requirement,
    to the extent that an auctioned service would interfere with the
    operation of Part 15 devices there. *Id*.

[^193]: P.L. 99-508, H. Rep. 99-647, 99th Cong., 2d Sess. at 33 (June
    19, 1986).

[^194]: This category is comprised of pervasively used devices whose
    energy output has no significant effect on the communications use of
    the spectrum (*e.g.*, automobile ignitions).

[^195]: 47 U.S.C. § 3(42). Likewise, the Administrative Procedures Act
    defines license as "the whole or a part of an agency permit,
    certificate, approval, registration, charter, membership, statutory
    exemption or other form of permission." 5 U.S.C. § 551(8).

[^196]: 47 C.F.R. § 15.1.

[^197]: Moreover, to the extent that Part 15 devices fall outside of the
    Section 301 licensing requirement (a proposition that is
    particularly apparent for such energy-transmitting apparatuses as
    automobile ignitions and induction furnaces), we note another reason
    why the Commission's unlicensed regime of equipment authorization is
    consistent with Congress's creation of the Section 307(e) individual
    license exceptions: the Section 307(e) services could never have
    been authorized under Part 15, because they use power levels that
    are too high. Thus, Section 301 would require them to be licensed,
    but for Congress's decision to exempt them.

[^198]: *See*, *e.g.*, Cingular comments of 12/5/01 at pg. 4, 11/13/01
    at pg. 3, 10/12/01 at pg. 3-4, 8/20/01 at pg. 3, 8/20/01 at pg. 5,
    2/23/01 at pg. 2-3. *See*, also, Alloy LLC (Cingular's former name)
    comments of 2/23/00 at pg. i, 6-8 and 17 (urging the Commission to
    adopt rules permitting UWB on a licensed basis and arguing against
    allowing unlicensed UWB operation).

[^199]: *See 1st R&O*, *supra*, at para. 12-19; *see*, also, *MO&O*,
    *supra*, at para. 95 (discussing the Commission's conclusion that
    the registered coordination of UWB imaging devices, as requested by
    Cingular in its 6/17/02 Petition for Reconsideration of the *1^st^
    R&O*, was not justified as there was no reason to believe that the
    devices, operating in compliance with the rules, would cause
    interference).

[^200]: *See MO&O*, *supra*, at para. 55-97.

[^201]: Cingular petition of 5/23/03 at pg. 22-23.

[^202]: Cingular petition of 5/23/03 at pg. 16-17.

[^203]: *Id*. at pg. 15, 16-17.

[^204]: *Id*. at pg. 18.

[^205]: Contrary to Cingular's claim, cellular systems also are
    addressed in paragraphs 200, 233, and 271 of the *1^st^ R&O*.

[^206]: *MO&O*, *supra*, at para. 86.

[^207]: *See ex parte* letter of October 12, 2001, from Jim Bugel of
    Cingular to Julius Knapp, Deputy Chief of the Commission's Office of
    Engineering and Technology.

[^208]: GPRs and technically similar wall-imaging systems are permitted
    to operate in the cellular and PCS frequency bands. As discussed in
    the *1^st^ R&O*, these devices do not present a threat of harmful
    interference to cellular or to PCS operations. *See 1^st^ R&O*,
    *supra*, at para. 185, 189 and 192 as examples.

[^209]: *MO&O*, *supra*, at para. 12-16. While the analysis described in
    these paragraphs is directed towards GPS reception, it is equally
    applicable to PCS operation.

[^210]: XSI comments of 9/4/03 at pg. 4.

[^211]: *See*, *e.g.*, Regulatory Policy Regarding the Direct Broadcast
    Satellite Service, *Memorandum Opinion and Order*, 94 FCC 2d 741,
    747-748 (1983) (citing, *e.g.*, *WWIZ, Inc.*, 37 FCC 685, 686
    (1964), aff'd sub nom., *Lorain Journal Co. v FCC*, 351 F 2d 824
    (D.C. Cir. 1965), cert denied, 383 U.S. 967 (1966), *Florida
    Gulfcoast Broadcasters, Inc., Broadcasting*, 4 Rad Reg 2d (P&F) 503
    (1965)).

[^212]: Cingular petition of 5/23/03 at pg. 23-25.

[^213]: *MO&O*, *supra*, at para. 56, 74, 86, and 95.

[^214]: *AT&T Wireless Services, Inc. v. F.C.C.*, 270 F.3d 959, 348
    U.S.App.D.C. 135 (D.C.Cir. Nov 09, 2001) ("*AirCell I*") (NO.
    00-1304), *on Remand to*, Aircell, Inc., 2003 WL 261920, 18 F.C.C.R.
    1926, 18 FCC Rcd. 1926 (F.C.C. Feb 10, 2003) ("*AirCell Remand
    Order*"), *petition for review denied by*, *AT&T Wireless Services,
    Inc. v. F.C.C.*, 365 F.3d 1095 (D.C.Cir. May 04, 2004) ("*AirCell
    II*").

[^215]: Cingular petition of 5/23/03 at pg. 23; *MO&O*, *supra*, at
    para. 74 and at footnote 188.

[^216]: Cingular petition of 5/23/03 at pg. 23.

[^217]: The Court found that the Commission adequately explained why it
    rejected the July 11, 1997, Texas-Oklahoma test data and the
    September 22, 1998, Florida test data upon which petitioners relied.
    *See* \[*AirCell I*\] at 968-69.

[^218]: *See* \[*AirCell I* at 968-69\] *id.*

[^219]: *See* \[*AirCell II* \] at 1102.

[^220]: *MO&O*, *supra*, at footnote 188.

[^221]: The Commission's review on remand of the July 10 test flight
    data showed that AirCell's mean signal strength exceeded --117 dBm
    only on one of the 24 test flights, and then only by .62 decibels, a
    trivial amount. It concluded, therefore, that AirCell was unlikely
    to cause harmful interference. *See* \[*Aircell II*\] at 1102; *see
    also* \[*AirCell Remand Order*\] at 1937.

[^222]: *See* \[*AirCell I*\] at 964. The Court also stated that "absent
    harmful interference, AirCell's new system does not trammel upon
    petitioners' rights as licensees." *Id.*

[^223]: A radio frequency device can generate unwanted emissions that
    may appear in any part of the radio spectrum.

[^224]: 47 C.F.R. § 15.209 of the current rules permits operation within
    the PCS bands at a higher level than that allowed from UWB devices
    and within the cellular bands at the same level as that allowed from
    UWB devices. 47 C.F.R. § 15.231 allows operation within the PCS and
    cellular frequency bands at considerably higher emission levels than
    those produced by UWB devices. Prior to June 23, 1989, 47 C.F.R.
    §§ 15.120, 15.122, 15.181-15.187, and 15.201-15.215 permitted
    unlicensed operation within the PCS and cellular bands at the higher
    power levels currently permitted under 47 C.F.R. § 15.231.

[^225]: The term "exclusivity" as used in the case refers to "geographic
    exclusivity and protection from interference." *See* \[*AirCell*\]
    at 963-64.

[^226]: *MO&O*, *supra*, at para. 74.

[^227]: *MO&O*, *supra*, at para. 124-131.

[^228]: SIA petition of 5/22/03 at pg. 3.

[^229]: *Id*. at pg. 3-8.

[^230]: *Id*. at pg. 8-9.

[^231]: *Id*. at pg. 3 and 9.

[^232]: XSI comments of 9/4/03 at pg. 1 and 2-4.

[^233]: SIA based the propagation attenuation on the square of the
    inverse distance, *i.e.*, the propagation loss in decibels is equal
    to 20 log (DF) -- 147.6 where D is the distance in meters and F is
    the frequency in Hertz. At 4 GHz, this formula becomes 20 log (D) +
    44.5 dB.

[^234]: *Evaluation of UWB and Lower Adjacent Band Interference to
    C-Band Earth Station Receivers*, Alion Science and Technology,
    February 11, 2004. ("Alion report") In the *MO&O*, the Commission
    stated that it would take appropriate action to protect the
    authorized services if tests or other sources provide any indication
    that its standards are not adequate. *See* *MO&O*, *supra*, at para.
    131. For this reason, we are accepting this report as a late filing
    in this proceeding. Written *ex parte* comments responding to this
    study were filed on April 9, 2004, by Motorola, Inc., on April 12,
    2004, by the Multiband OFDM Alliance, and on June 4, 2004, by the
    Coalition of C‑Band Constituents.

[^235]: Alion report at pg. 6-7.

[^236]: Under this condition, Alion calculated the path loss using free
    space propagation, *i.e*., based on the square of the inverse of the
    distance, where the propagation loss in dB is equal to 20 log (DF)
    -- 147.6 where D is the distance in meters and F is the frequency in
    Hertz. At F = 4 GHz, this formula becomes 20 log (D) + 44.5 dB.

[^237]: On March 5, 2004, the Coalition submitted a letter to the
    Commission stating that it now believes that a higher density and a
    higher UWB operating duty cycle should be applied, based on the
    number of USB computer ports available within the U.S. and its
    speculation that UWB devices would be attached to these ports.

[^238]: The limited transmission range also would effectively preclude
    the use of hand-held UWB devices for vehicle-to-vehicle
    communications.

[^239]: While no data is available for the attenuation caused to outdoor
    UWB devices due to hand-held operation, Sprint found that PCS
    handsets operating at 1900 MHz suffered a 12 dB to 15 dB attenuation
    due to "head loss," *i.e.*, signal blockage by the user. *See*
    Sprint comments of 9/12/00 at Attachment 2, pg. 2-3. It is expected
    that the attenuation from the hand and body shielding at the 4 GHz
    FSS frequency would be at least as high, if not more, as that in the
    1.9 GHz PCS band.

[^240]: The average building attenuation at 4 GHz is 12 dB, as
    determined by NTIA. *See* NTIA Special Publication 01-43,
    *Assessment of Compatibility between Ultrawideband Devices and
    Selected Federal Systems*, January 2001, at pg. 5-30 to 5.31.

[^241]: Propagation loss, after accounting for the 12 dB building
    attenuation, should approach inverse distance to the fourth or, with
    F = 4 GHz, a loss of 40 log (D) + 44.5 dB.

[^242]: At a frequency of 1.5 GHz, NTIA found that "aggregate
    interference from uniformly distributed emitters at distances of
    less than 1 km would decrease by at least 15 dB in suburban areas
    and 20 dB in urban areas, as compared with a smooth Earth
    propagation loss" and that emissions from emitters beyond one km
    were reduced by 30 dB in suburban environments and 40 dB in urban
    environments, virtually eliminating any aggregate effects from UWB
    devices beyond 1 km. NTIA added that these signal losses increase at
    frequencies above 1.5 GHz. See NTIA Special Publication 01-43,
    *supra*, at pg. 5-28 and 5-29.

[^243]: The Commission's analysis only varied the percentages of devices
    that were operated indoors and outdoors along with the application
    of a 12 dB building attenuation factor for indoor UWB transmitters.
    If the Commission had assumed even more realistic operating
    conditions by applying intervening objects and a more reasonable
    propagation factor to outdoor UWB transmitters, multiple intervening
    objects to indoor UWB transmitters, the possibility that the UWB
    emitter and the satellite antenna are not line-of-sight with each
    other, and an activity factor, the results would have been even
    lower.

[^244]: 47 C.F.R. § 15.5.

[^245]: The RFA, *see* 5 U.S.C. § 601 -- 612, has been amended by the
    Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA),
    Pub. L. No. 104-121, Title II, 110 Stat. 857 (1996).

[^246]: 5 U.S.C. § 605(b).

[^247]: 5 U.S.C. § 601(6).

[^248]: 5 U.S.C. § 601(3) (incorporating by reference the definition of
    "small-business concern" in the Small Business Act, 15 U.S.C. §
    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."

[^249]: 15 U.S.C. § 632.

[^250]: *See* 5 U.S.C. § 801(a)(1)(A).

[^251]: *See* 5 U.S.C. § 605(b).