**Before the**

**Federal Communications Commission**

**Washington, D.C. 20554**

+----------------------------------+----+------------------------------+
| In the Matter of                 | *  | ET Docket No. 03-104         |
|                                  | *) |                              |
| Carrier Current Systems,         | ** | ET Docket No. 04-37          |
| including Broadband over Power   |    |                              |
| Line Systems                     | *  |                              |
|                                  | *) |                              |
| Amendment of Part 15 regarding   | ** |                              |
| new requirements and measurement |    |                              |
| guidelines for Access Broadband  | *  |                              |
| over Power Line Systems          | *) |                              |
|                                  | ** |                              |
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|                                  | ** |                              |
+----------------------------------+----+------------------------------+

**[COMMENTS OF THE NATIONAL TELECOMMUNICATIONS AND INFORMATION
ADMINISTRATION]{.underline}**

+-----------------------------------+-----------------------------------+
| Michael D. Gallagher              | Kathy Smith                       |
|                                   |                                   |
| Acting Assistant Secretary for    | Chief Counsel                     |
|                                   |                                   |
| Communications and Information    | National Telecommunications and   |
|                                   |                                   |
| Fredrick R. Wentland              | Information Administration        |
|                                   |                                   |
| Associate Administrator           | U.S. Department of Commerce       |
|                                   |                                   |
| Office of Spectrum Management     | Room 4713                         |
|                                   |                                   |
| Thomas Sullivan                   | 1401 Constitution Avenue, N.W     |
|                                   |                                   |
| Edward Drocella                   | Washington, DC 20230              |
|                                   |                                   |
| Electronics Engineers             | \(202\) 482-1816                  |
|                                   |                                   |
| Office of Spectrum Management     |                                   |
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|                                   |                                   |
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June 4, 2004

TABLE OF CONTENTS

SUMMARY................................................................................................\...iv

DISCUSSION
................................................................................................2

I. NTIA CONCURS WITH THE COMMISSION\'S DEFINITION OF ACCESS BPL

AND SUGGESTS ADOPTION OF A DEFINITION FOR IN-HOUSE BPL............\...3

II\. BPL IS A WIN-WIN PROPOSITION TO THE EXTENT THAT EXISTING AND

FUTURE POWER LINE NOISE PROBLEMS ARE
REDUCED.........................\...4

III\. NTIA AGREES WITH THE COMMISSION'S TREATMENT OF EMISSION

LIMITS AND RECOMMENDS THAT SUPPLEMENTAL EMISSION

RESTRICTIONS BE EMPLOYED IN LIMITED FREQUENCY

BANDS AND GEOGRAPHIC
AREAS..........................................................7

IV\. THE COMMISSION'S ACCESS BPL OPERATIONAL REQUIREMENTS WILL BE
EFFECTIVE AND NTIA SUGGESTS IMPLEMENTATION OF COORDINATION PROCEDURES TO
FURTHER REDUCE INTERFERENCE RISKS......................8

V. NTIA RECOMMENDS CERTIFICATION BY ACCESS BPL OPERATORS RATHER THAN
VERIFICATION BY MANUFACTURERS TO ALIGN AUTHORIZATION

OBLIGATIONS AND BENEFITS WITH THE RESPONSIBLE PARTY.................14

VI\. NTIA SUPPORTS THE COMMISSION\'S PROPOSED MEASUREMENT

GUIDELINES AND SUGGESTS ADDITIONAL STEPS TO FURTHER

> REDUCE INTERFERENCE
> RISKS.............................................................15
>
> A. A MEASUREMENT DISTANCE OF TEN METERS SHOULD BE USED
>
> WITH RESPECT TO OVERHEAD POWER LINES AND BPL DEVICES
>
> WITH A MODIFIED DISTANCE EXTRAPOLATION FACTOR...\..............16

B. MEASUREMENTS SHOULD FULLY ADDRESS RADIATION FROM BPL

> DEVICES AND POWER LINES TO WHICH THEY ARE CONNECTED...\...17
>
> C. MEASUREMENT ANTENNA HEIGHT SHOULD BE ONE METER AND
>
> A 5 dB HEIGHT CORRECTION FACTOR SHOULD BE APPLIED............19
>
> D. ALL BPL OPERATING FREQUENCIES SHOULD BE CONSIDERED
>
> AND BPL EQUIPMENT SHOULD INCORPORATE THE
>
> NECESSARY OPERATIONAL POWER CONSTRAINTS .......................21
>
> E. MEASUREMENTS BELOW 30 MHz SHOULD USE A CALIBRATED
>
> LOOP ANTENNA WITH AN APPROPRIATE MAGNETIC-TO-ELECTRIC
>
> FIELD CONVERSION FACTOR AND AN ELECTRIC FIELD ANTENNA SHOULD BE USED
> ABOVE 30 MHz................................................22
>
> F. REPRESENTATIVE POWER LINES USED FOR BPL MEASUREMENTS SHOULD BE
> CAREFULLY SELECTED TO ENSURE THAT PEAK EMISSIONS ARE
> MEASURED.......................................................23
>
> G. CERTAIN ADDITIONAL MEASUREMENT PROVISIONS SUCH AS MEASUREMENT
> BANDWIDTH SHOULD BE MANDATORY FOR BPL ..23
>
> H. SPECTRAL POWER DISTRIBUTIONS OF BPL EMISSIONS SHOULD BE
>
> MEASURED AND INCLUDED IN THE MEASUREMENT REPORT.........24

VII\. ACCESS BPL MAY WARRANT ITS OWN RULE PART

OR SUB-PART UNDER PART
15..............................................................24

VIII\. FURTHER REGULATORY ACTION MAY BE NEEDED

AFTER ADDITIONAL STUDIES ARE COMPLETED AND

ADDITIONAL EXPERIENCE IS
GARNERED...............................................25

IX\.
CONCLUSION...............................................................................................26

TECHNICAL APPENDIX

SUMMARY

On March 26^th^, President Bush established a national objective to make
broadband access available and affordable to every American by 2007 and
called for "...technical standards to make possible new broadband
technologies, such as the use of high-speed communications directly over
powerlines."[^1] To this end, NTIA has completed additional BPL studies
that, with the NTIA Phase 1 study, provide the basis for NTIA\'s
recommended framework of technical rules for Broadband over Power Line
("BPL") systems that will responsibly address interference concerns and
BPL operational requirements. NTIA urges the Commission to promptly
adopt effective technical rules to enable BPL proponents to develop and
implement the necessary new design features and operating practices and
obtain requisite new authorizations in time to contribute significantly
toward fulfillment of the President's vision for universal affordable
broadband Internet access.

NTIA recommends adoption of several new BPL rule elements that couple
with the Commission\'s proposed rules to reduce risks of interference
from BPL systems to authorized radiocommunications. These rules also
help ensure that interference from BPL systems would be eliminated
expeditiously with little effort needed on the part of any radio
operator. Relative to existing BPL rules, these recommended new rules
will shift the emphasis away from elimination of interference from BPL
systems toward prevention of interference through adaptation of
well-proven spectrum management practices.

The potential benefits of BPL identified in the Notice of Inquiry
(\"NOI\") phase of this proceeding warrant acceptance of a small and
manageable degree of interference risk. The risks

likely will be moderated by a concurrent reduction in existing
interference risks from power line noise throughout the spectrum up to
600 MHz. Strong existing radio noise emissions from power lines often
span frequencies well beyond those used for BPL - this noise must be
reduced to enable acceptable Access BPL performance while complying with
the proposed field strength limits. Moreover, in the long-term, BPL
deployment should yield additional motivation and resources for
maintaining the electric power distribution system, predicting and
preventing faults, and achieving more rapid repairs in an affordable
manner. Thus, although limited reliability of electrical power systems
was cast by some parties as a BPL drawback in the NOI phase, widespread
deployment of BPL may actually induce substantial reliability
improvements.

*Reduction of Interference Risks*

To reduce risks of interference from BPL systems, NTIA endorses the
Commission's proposed field strength limits and its thrust to refine BPL
measurement provisions that ensure compliance with these limits. In
addition, to ensure that the Commission\'s proposed BPL notification
database is useful for interference prevention, NTIA recommends
specification of voluntary *a priori* frequency coordination procedures
in connection with a requirement for BPL operators to notify planned BPL
deployments at least thirty days in advance of activation. Concerned
shortwave broadcast listeners and other radio operators could inform BPL
operators of their local radio reception parameters to enable the BPL
operator to avoid co-frequency BPL operations that may pose high risks
of interference. BPL operators also could identify local radio
communications operations by consulting the Commission\'s database of
licensed radio stations. In response to advance notifications, NTIA
would provide information on local Federal Government radio receiver
operations that will enable reduction of interference risks. Many
Federal Government receivers are positioned at known, fixed locations.
The custodian of the notification database could provide, on a web site,
a standard form and e-mail address for alerting the BPL operator of
potentially vulnerable radio operations.

NTIA also recommends mandatory power control and adoption of limited
coordination areas, excluded frequency bands, and exclusion zones to
protect the most sensitive and vulnerable Federal Government radio
receivers. Because radio noise on power lines can vary by upwards of 20
dB throughout a day, a rule should require adjustment of BPL signal
power to preclude unnecessarily high levels of radiated emissions. NTIA
is evaluating the potential interference risk reductions accrued from
power control, but it is obvious that reducing Access BPL emissions by
about 20 dB (a factor of 100) when noise is at relatively low levels
will substantially reduce interference risks. Prior to implementation of
Access BPL in a coordination area, such as the National Radio Quiet Zone
from which extraordinarily sensitive radio astronomy observations are
made, the BPL operator should be required to contact the specified
authority for the coordination area in order to mutually determine
whether BPL constraints are needed to prevent interference. BPL
operations should be prohibited nationally within certain excluded
frequency bands, such as the band 74.8-75.2 MHz used for aircraft
reception of marker beacons. BPL use of certain frequencies should also
be prohibited in specified exclusion areas, for example, in small areas
around United States Coast Guard ("Coast Guard") coast stations in the
band 2173.5 -- 2190.5 kHz used for Global Maritime Distress and Safety
System communications.

Perhaps the most broadly effective reductions in BPL interference risks
will be achieved through provisions for BPL compliance measurements.
Existing Access BPL measurement provisions can mistakenly indicate
compliance with field strength limits when the limits actually are
substantially exceeded. NTIA agrees with the BPL Notice of Proposed
Rulemaking (NPRM) proposals to measure at a one-meter height at a
uniform distance of ten-meters to simplify measurement logistics.
However, measurement at the distances along the power lines (fractions
of a wavelength) proposed in the BPL NPRM will fail to reveal the peak
field strength in many cases. To prevent underestimation of peak field
strength during compliance measurements, NTIA recommends a comprehensive
search for the peak field strength along the power lines at a height of
one-meter. To avoid the need to search for the peak field in the height
dimension as well, NTIA recommends use of a 5 dB height correction
factor. NTIA\'s analysis shows that use of a 5 dB height correction
factor with the peak field strength measured at a one-meter height is a
good estimate of the electric field strength not exceeded at 80% of the
heights above one-meter. Because power lines have frequency selective
radiation properties and BPL device frequencies are, or should be,
tunable in frequency, a rule should require measurement of Access BPL
radiated emissions with the BPL system bandwidth successively tuned to
cover every frequency at which the BPL system can operate. NTIA concurs
with the BPL NPRM proposal to use a loop antenna at frequencies below 30
MHz and an electric field antenna at higher frequencies. However,
because a loop antenna measures magnetic field strength and the
measurements are performed in the near-field, NTIA recommends that an
appropriate magnetic-to-electric field strength conversion factor be
applied to enable correct comparisons of measurements with the electric
field strength limit. In order to ensure that the highest representative
field strength levels are measured and the limits are not exceeded, NTIA
further recommends adoption of guidelines for judicious selection of the
three Access BPL deployments for *in situ* measurements and a rule
specifying how those measurements are to be applied. Representative
spectral power distributions of Access BPL signals should also be
measured and included in the measurement report to facilitate
identification of the BPL signals in the event they cause interference.

*Interference Mitigation*

NTIA agrees with the BPL NPRM proposals to require that Access BPL
systems be capable of shut-down and adjustment of frequency usage to
eliminate interference. However, the rendition of shut-down requirements
in 47 CFR 15.5(c) is inadequate and misleading in the unique case of
Access BPL. Shut-down is a last resort after first attempting the many
other interference mitigation techniques available to Access BPL
systems. For example, to ensure that suspected interference from BPL
systems is quickly diagnosed and eliminated if confirmed, NTIA
recommends that each notification of BPL deployment include a telephone
point-of-contact for receiving interference complaints. This point of
contact should be required to immediately determine and report to the
complainant whether the BPL system is locally using the frequencies at
which interference is suspected. If this does not dismiss BPL as the
possible cause of interference, the point-of-contact should be required
to perform or schedule a simple test in cooperation with the complainant
that will determine whether the Access BPL network element(s) are the
likely cause of interference. Specifically, the suspected BPL network
element(s) could be briefly shut off or BPL device frequencies could be
changed to eliminate co-frequency operation while the complainant is
operating the receiver and reporting its performance. To ensure that
diagnosis of suspected interference can be conducted independently of
the BPL operator if so desired, for each type of device to be deployed,
Access BPL system notifications should include the modulation type(s),
number(s) of carriers, minimum and maximum carrier spacing, symbol
rate(s) per carrier, range of transmission duty cycle, and the multiple
access technique. Insofar as BPL signal identification using these
parameters requires a spectrum analyzer, NTIA is further considering
whether a code signal should be transmitted to enable identification
using a standard communications receiver - modulation of any such a code
must not increase interference risks.

On the basis of worst-case oriented analyses of ionospheric propagation
and aggregation of radiated emissions from Access BPL systems, NTIA
concludes that hundreds of thousands of Access BPL devices conforming to
current BPL rules (limits and measurement procedures) would have to be
deployed nationally to cause a 1 dB increase in median radio noise power
at any location, globally. Using NTIA's recommended rules, chiefly the
mandatory power control and use of a 5 dB height correction factor, it
would take millions of BPL devices to cause a 1 dB increase in median
radio noise. NTIA is further studying this phenomenon and recommends
that BPL advance notifications include the maximum number of Access BPL
devices that will be deployed. These entries should be updated quarterly
to reflect actual deployment in order to enable on-going predictions of
ionospheric propagation and aggregation of BPL emissions to forecast the
onset of any significant increase in radio noise levels. Thus, this is
not a potential near-term issue that should delay adoption of BPL rules.

*Other Authorization Provisions*

Other Access BPL authorization provisions should require certification
by the operator rather than verification by the manufacturer. This will
align benefits and obligations with the responsible party, who will have
strong incentives to minimize interference risks. Certification is
appropriate because interference risks posed by Access BPL systems are
high relative to other unintentional emitters and the newness of the
Access BPL measurement procedures warrants review of measurement
reports. NTIA agrees with the definition of Access BPL proposed in the
BPL NPRM and recommends adoption of a complementary definition for
In-House BPL. This would properly frame the respective rules and
measurement guidelines to avoid misinterpretation or overlooking of
applicable rules. The measurement provisions most important to
prevention of interference should be codified as rules rather than
guidelines. For example, compliance measurement bandwidth should be a
rule rather than a provision incorporated by reference in guidelines,
because use of measurement bandwidths other than the intended 9 kHz and
120 kHz values could yield significant error and elevated risk of
interference.

*Recommended Near-Term Rulemaking Actions*

Thus, in light of the scope of available studies and other evidence,
NTIA further recommends that the Commission proceed expeditiously to
rulemaking for In-House BPL and Access BPL using low- and medium-voltage
("LV" and "MV") power lines. NTIA concurs with the BPL NPRM proposal to
review measurement guidelines for In-House BPL later, after
international studies are completed. NTIA believes that expressed
interest as well as available technical descriptions, operating
experience and studies of potential interference are inadequate at this
time to support establishment of rules for Access BPL using high voltage
("HV") transmission lines or any BPL use of frequencies outside the 1705
kHz to 80 MHz frequency range. This, too, could be revisited later.
Finally, NTIA recommends establishing a new, dedicated rule part or
sub-part of Part 15 for Access BPL. This recommendation is made because
the Access BPL rules proposed in this NPRM are substantial, unique to
Access BPL, and would be difficult to understand if incorporated into
Part 15 of the Commission's Rules. Moreover, certain existing Part 15
rules for unintentional emitters should not be applied to Access BPL.

**Before the**

**Federal Communications Commission**

**Washington, D.C. 20554**

+----------------------------------+----+------------------------------+
| In the Matter of                 | *  | ET Docket No. 03-104         |
|                                  | *) |                              |
| Carrier Current Systems,         | ** | ET Docket No. 04-37          |
| including Broadband over Power   |    |                              |
| Line Systems                     | *  |                              |
|                                  | *) |                              |
| Amendment of Part 15 regarding   | ** |                              |
| new requirements and measurement |    |                              |
| guidelines for Access Broadband  | *  |                              |
| over Power Line Systems          | *) |                              |
|                                  | ** |                              |
|                                  |    |                              |
|                                  | *  |                              |
|                                  | *) |                              |
|                                  | ** |                              |
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|                                  | ** |                              |
|                                  |    |                              |
|                                  | *  |                              |
|                                  | *) |                              |
|                                  | ** |                              |
+----------------------------------+----+------------------------------+

**[COMMENTS OF THE NATIONAL TELECOMMUNICATIONS AND INFORMATION
ADMINISTRATION]{.underline}**

The National Telecommunications and Information Administration (NTIA),
an Executive Branch agency within the Department of Commerce, is the
President's principal adviser on domestic and international
telecommunications policy, including policies relating to the nation's
economic and technological advancement in telecommunications.
Accordingly, NTIA makes recommendations regarding telecommunications
policies and presents Executive Branch views on telecommunications
matters to the Congress, the Federal Communications Commission
(Commission), and the public. NTIA is also responsible for managing the
Federal Government's use of the radio frequency spectrum. NTIA submits
these comments in response to the Commission's Notice of Proposed
Rulemaking in the above-captioned proceeding.[^2] These comments make
frequent reference to NTIA's recently released Phase 1 report addressing
potential interference from Broadband over Power Line ("BPL") systems,
as supplemented by the preliminary elements of NTIA's Phase 2 report
that are presented in the Technical Appendix, herewith.[^3] NTIA has
coordinated these comments with the Interdepartment Radio Advisory
Committee ("IRAC").

DISCUSSION

In the Notice of Inquiry ("NOI") phase of this BPL proceeding, thousands
of commenters expressed various degrees of support and opposition for
BPL.[^4] Proponents concluded that harmful interference is not expected
but can be eliminated through various means if it occurs. Numerous other
parties envisaged scenarios under which BPL systems could cause harmful
interference to radio communications. NTIA believes that all of these
views are reasonable because both interference-free and harmful
interference scenarios could occur.[^5] Thus, NTIA has focused on the
following technical questions:

-   What interference risks are posed by BPL, and if they are too high,
    how can the risks be suitably reduced while fulfilling at least the
    minimum BPL requirements?

-   If interference from a BPL system is suspected, what are the
    difficulties in diagnosing the suspected interference and
    eliminating harmful interference?[^6]

As set forth herein and in the BPL NPRM, satisfactory answers to those
technical questions are available for In-House and Access BPL systems
using low- and medium-voltage (\"LV\" and \"MV\") power lines. NTIA
believes that this rulemaking is timely for application of those
technical answers in appropriate regulatory solutions that reflect
careful limitation and management of interference risks. NTIA's vantage
point includes many years of experience in successful management of
interference risks. The rules must ensure that BPL systems will consume
only a small amount of spectrum resources, not otherwise utilized by
radio systems. The technical answers at hand for In-House and LV/MV
Access BPL are reliable and should be applied as soon as possible. NTIA
has not studied Access BPL systems that use high-voltage (\"HV\")
transmission lines and suggests that this highly-specialized form of BPL
be considered later. Moreover, compliance measurement procedures for
In-House BPL systems procedures should also be revisited later as
suggested by the Commission.[^7] Rather than delay this rulemaking until
these and perhaps other issues are further addressed, NTIA prefers to
proceed expeditiously with this rulemaking in order to establish
modified rules that yield reduced interference risks and greater
regulatory certainty for BPL proponents and radio interests alike. BPL
using HV transmission lines and measurement guidelines for In-House BPL
can be revisited later.

**I. NTIA CONCURS WITH THE COMMISSION\'S DEFINITION OF ACCESS BPL**

AND SUGGESTS ADOPTION OF A DEFINITION FOR IN-HOUSE BPL

The Commission proposes a definition for \"Access BPL\" that includes in
its scope all \"\...electric power lines owned, operated or controlled
by an electric service provider.\"[^8] NTIA agrees with this definition
and that it is needed in order to properly specify the rules and
measurement guidelines applicable to Access BPL. Likewise, the
Commission should consider a definition of \"In-House BPL\" to properly
frame the applicable rules and measurement guidelines. Adoption of a
definition for In-House BPL together with the Access BPL definition
would fully define all forms of BPL. To this end, NTIA suggests the
following draft definition:

> [In-House Broadband over Power Line (In-House BPL)]{.underline}: A
> carrier current system that transmits radio frequency energy by
> conduction over electrical power lines that are not owned, operated or
> controlled by an electric service provider. The electric power lines
> may be aerial (overhead), underground, or inside walls, floors or
> ceilings of user premises. In-House BPL devices may establish closed
> networks within the user premises or provide connections to Access BPL
> networks, or both.

**II. BPL IS A WIN-WIN PROPOSITION TO THE EXTENT THAT EXISTING**

**AND FUTURE POWER LINE NOISE PROBLEMS ARE REDUCED**

The many potential public benefits of BPL technology and BPL
capabilities for eliminating interference argue strongly for accepting a
degree of interference risk.[^9] In fact, existing power line noise and
reliability problems that were cast as BPL detriments in the NOI phase
of this proceeding likely will be remedied as a result of widespread
Access BPL deployment. NTIA does not expect Access BPL systems to
compound existing risks of interference from radio frequency noise
generated by electrical power distribution systems -- a problem that has
been explained in numerous comments.[^10] Instead, to the benefit of
radio proponents, strong power line noise emissions likely will be
reduced in the process of deploying BPL systems. Many commenters noted
that electrical power distribution systems occasionally fail (*e.g*.,
during adverse weather) and concluded that BPL will not be
reliable.[^11] NTIA disagrees and believes that in the long-term, Access
BPL likely will induce improved reliability of the electrical power
distribution system and enable more expeditious restoration of
electrical service when failures occur. NTIA believes that such a
reliability enhancement to critical infrastructure would greatly benefit
individuals, businesses and the government -- everyone - regardless of
whether they subscribe to Access BPL.

Reduction of strong power line noise is a basic technical requirement
necessary for acceptable performance of BPL systems under the field
strength limits proposed by the Commission and endorsed by NTIA. As in
radio systems, the signal-to-noise power ratio (\"S/N\") at BPL
receivers must exceed certain thresholds in order to achieve reliable
transmission with the requisite throughput. If the noise power at the
BPL receiver is unnecessarily high, the BPL signal levels also will have
to be unnecessarily high. Reducing power line noise can enable
reductions in BPL signal power such that operation near the field
strength limit may not be needed. Most strong power line noise emissions
span not only the frequencies of prime interest for BPL operations, but
also many other radio frequencies at Medium Frequency (MF), High
Frequency (HF), Very High Frequency (VHF) and lower Ultra High Frequency
(UHF) bands not used by BPL (generally spectrum below 600 MHz). Thus,
reducing power line noise should reduce certain interference risks,
perhaps including risks at frequencies used by the BPL system. Moreover,
deployment of BPL could increase the likelihood that problematic power
line noise will be diagnosed and repaired.

Apart from the BPL measurement campaigns, NTIA has measured field
strength levels from power line noise that are higher than the limits
proposed for BPL radiated emissions and these existing anomalies pose
greater local interference risks than Access BPL. In contrast, during
its BPL measurements, NTIA observed that power line noise levels in the
vicinity of BPL systems were substantially lower than predicted typical
levels that include as a component the typical levels of power line
noise. Substitution of BPL emissions for the strong, much
wider-bandwidth power line noise emissions will broadly reduce risks of
interference to radiocommunications. This is not to say that NTIA
expects there will be a net, nationwide reduction of interference risks;
instead, NTIA believes there will be at least partial offsetting of the
interference risks posed by BPL.

When considering the reliability aspects of electrical service and
Access BPL, it is instructive to consider electrical service failures
and restoration under scenarios that include and exclude widespread BPL
deployment. Presently, without Access BPL, electrical utility companies:
maintain substantial crews and equipment sufficient to rapidly repair
certain numbers and geographic distributions of failures; monitor and
forecast adverse weather and other leading indicators of potential
failures in order to marshal resources in advance of potential failures;
and pool service restoration resources among companies in preparation
for numerous, potentially widespread failures. Detection and diagnosis
of many types of failures rely on "complaints" from electricity
consumers. These operations balance the costs of electrical service with
the amount of resources available for diagnosis and repair of failures.
With widespread deployment of Access BPL, however, it will be possible
to speed detection and diagnosis of electrical system failures and there
likely will be increased demand and revenue subsidies for qualified
electric system repair and maintenance personnel and equipment.[^12] In
today's high-productivity environment, by adding Access BPL to the
equation, the new manpower and equipment needed to install and maintain
BPL systems likely will create economies of scale that benefit the
reliability of both electrical power distribution and BPL.

III\. NTIA AGREES WITH THE COMMISSION'S TREATMENT OF EMISSION LIMITS AND
RECOMMENDS THAT SUPPLEMENTAL EMISSION

RESTRICTIONS BE EMPLOYED IN LIMITED FREQUENCY

BANDS AND GEOGRAPHIC AREAS

NTIA concurs with the Commission\'s proposal to continue to make Access
BPL systems subject to existing radiated emissions limits for carrier
current systems.[^13] Perceived BPL interference risks preclude
relaxation of radiated emission limits for BPL systems, and interference
risks can and should be suitably reduced through refinement of the
compliance measurement provisions.[^14] However, additional emission
restrictions are needed in certain frequency bands and geographic areas
in order to protect radiocommunications consistent with current rules
and practices. These restrictions would have the following forms:
geographic \"coordination areas,\" wherein BPL deployments at any
frequency in those areas must be pre-coordinated by BPL operators;
excluded bands, in which certain frequencies are not to be used by BPL
in any geographic area; and small geographic \"exclusion zones,\"
wherein BPL emissions are forbidden at specified frequencies in
accordance with protection requirements and electromagnetic
compatibility studies. These coordination areas, excluded bands and
exclusion zones would be defined in the rules for Access BPL systems and
would virtually eliminate certain interference risks. For example, the
National Radio Quiet Zone (\"NRQZ\") would be a BPL coordination area;
the band 74.8-75.2 MHz used for aircraft reception of marker beacons
used in conjunction with the Instrument Landing System (\"ILS\") would
be an excluded band; and there would be exclusion zones around Coast
Guard coast stations in the 2173.5 - 2190.5 kHz band used for distress
alerting.[^15] BPL proponents have already demonstrated capabilities for
implementing these restrictions, *e.g.*, by notching out frequencies
allocated to the amateur radio service. NTIA believes that only a
minimal number of such restrictions should be codified in the rules in
light of the *a priori* frequency coordination procedures NTIA
recommends. NTIA is continuing to study potential coordination areas,
excluded bands and exclusion zones to identify the minimum requisite set
of such restrictions.

IV\. THE COMMISSION'S ACCESS BPL OPERATIONAL REQUIREMENTS WILL BE
EFFECTIVE AND NTIA SUGGESTS IMPLEMENTATION OF COORDINATION PROCEDURES TO
FURTHER REDUCE

INTERFERENCE RISKS

NTIA believes that BPL operators, as the parties responsible for
eliminating harmful interference, will voluntarily implement equipment,
organizational elements, and installation and operating practices that
prevent interference and facilitate interference mitigation. Market
appeal of BPL could quickly evaporate if BPL systems were to endemically
cause interference and have to be shut down with operating
authorizations swiftly revoked if necessary.[^16] Thus, BPL operators
have strong incentives to prevent and eliminate interference. However,
to preserve the high degree of regulatory certainty enjoyed by licensed
radio operators, the rules for Access BPL should require implementation
of the most widely effective operational features for preventing and
eliminating interference. The Commission proposes to require BPL systems
to have operational capabilities such as dynamic or commanded power
reduction, commanded shut-down, and local exclusion of BPL use of
specific frequencies or bands.[^17] The Commission also

proposes a requirement that BPL operators notify key BPL system
parameters to an industry-operated entity that will enter and maintain
these parameters in a publicly accessible database.[^18] NTIA fully
supports those proposals as discussed below and proposes to require *a
priori* coordination of potentially affected receiving stations at known
locations or service areas. NTIA believes that imposition of
coordination requirements on BPL operators to receive and consider
coordination data will not result in significant costs while providing
the substantial benefit of preventing interference to radio receivers at
known locations. Further, to speed resolution of cases of suspected
interference, NTIA recommends that BPL operators be required to promptly
diagnose suspected interference and eliminate actual interference from
BPL systems.

Adaptive or commanded power control reduces interference risks by
maintaining the desired signal near the requisite, minimum power level,
in response to measured or predicted transmission channel conditions.
Power line noise resulting from ingress of ambient radio noise can vary
by upwards of 20 dB throughout the day and seasonally, especially at
frequencies below 12 MHz. Additional variations in power line noise
power can arise at frequencies generally below 600 MHz from faults in
power distribution components and operation of certain customer premises
equipment. Rather than setting BPL device output power at a constant
level that is high enough to yield the requisite BPL S/N during peak
noise levels, interference risks can be significantly reduced by
adjusting power consistent with variations in noise power that cannot
reasonably be eliminated prior to BPL deployment. Assuming that
protection of local receivers at locations is pre-coordinated, as
discussed below, BPL power increases can be suitably limited or
locked-out at the locally used radio frequencies as needed.

BPL frequency tuning capabilities can be used to prevent or rapidly
diagnose and

eliminate interference. Interference would be prevented by precluding
BPL operation on locally used frequencies when there is insufficient
distance separation for interference-free, co-frequency operation with
respect to radio receivers at known nearby locations. This includes
mobile receivers at frequencies above 30 MHz that routinely operate
within a known base station coverage area.[^19] The distance separation
criteria for virtually risk-free, co-frequency operation would be
applied by the BPL operator when selecting BPL frequencies within
pre-established coordination zones or in the course of the frequency
coordination in response to BPL deployment notifications. To quickly
diagnose claims of interference while sustaining BPL service, the BPL
operator could determine whether a BPL system is the cause of suspected
interference by shifting its operating frequency. If it is determined
that the BPL system is causing interference, the interfering BPL system
could be commanded to use only non-interfering frequencies. To achieve
these benefits, NTIA believes that BPL systems should be required to
have frequency agility that is capable of precluding BPL transmissions
in bands of at least 3 kHz at frequencies below 30 MHz and 30 kHz at
frequencies above 30 MHz. In addition, insofar as many BPL frequency
constraints may be needed at some locations, it would be beneficial if
BPL devices were capable of using frequencies anywhere throughout the
frequency range authorized for BPL operations. Furthermore, to avoid
potentially impairing mobile radiocommunications over sizable contiguous
areas, geographically adjacent Access BPL network elements should not
use the same frequency bands if the bands are used by mobile radio
receivers.

The Access BPL deployment notification requirements proposed by the
Commission should be made retroactive and BPL operators should be
required to notify planned deployments at least 30 days in advance of
implementation and to consider the coordination data they receive
regarding local radio receiver operations in order to prevent
interference. Spectrum management science and engineering have yielded
various applicable algorithms for optimally planning frequency usage
that avoids risking interference. Advance notification would, via
e-mails, allow local radio receiver operators to inform the BPL operator
of potential interference situations involving radio receivers at known
locations or mobile receivers that are routinely operated in the planned
deployment area. This action would be voluntary on the part of any radio
operator. BPL operators should extract local frequency assignment data
from the pertinent Commission databases, identify the locations and
frequencies used by local radio receivers, and plan BPL operating
frequencies in a manner that avoids BPL interference to local
co-frequency radio receivers.[^20] To protect federal government radio
communications, in response to each advance notification, NTIA plans to
provide the BPL operator with information that will enable prevention of
interference to local federal radio operations. To effect this frequency
coordination, a single, centralized, web-based database should provide
details of planned BPL system deployments sufficient to enable
identification of local radio operations that may be affected. NTIA
recommends that planned BPL system locations be notified in the form of
one or more geographic coordinates (in decimal degrees) and associated
radii (in kilometers). One or more such coordinate-radii pairs should be
notified to describe a planned, near-term deployment area without
including an excessive amount of area outside the area where deployment
is planned. NTIA further recommends notification of the earliest
anticipated date of actual operation within each deployment area so that
NTIA can properly prioritize its responses to notifications.

To facilitate radio operator diagnosis of suspected interference from
BPL systems, notifications of Access BPL deployments should include the
BPL device multiple access technique, modulation details (modulation
type, carrier spacing parameters and data rate on each carrier), and the
method of power control. The multiple access technique and modulation
details would sufficiently describe the BPL emission waveforms to enable
identification of BPL emissions using a spectrum analyzer. BPL
transmission of identifying codes could facilitate identification of BPL
emissions using a conventional radio receiver; however, NTIA is further
considering the potential need and whether transmission of such codes
would increase interference risks. Using these notified parameters,
diagnosis and confirmation of suspected BPL interference could be made
independently of the BPL operator, if so desired. However, there should
be no fundamental need for such actions if, as NTIA recommends, the BPL
operator is required to quickly diagnose suspected interference and
eliminate harmful interference upon complaint.

Advance notifications for each deployment area should also specify the
maximum number of each type of Access BPL device to be deployed in the
specified area. Subsequent notifications should be submitted at least
quarterly for each deployment area, as needed, to report the total
numbers of each type of device that have been deployed and to update
other advance notification parameters. The identity of the device
manufacturer(s) should not be included in these notifications without
their explicit approval. Among other things, over time this data will
assist NTIA in updating its predictions of increases in ambient radio
noise due to ionospheric propagation and aggregation of emissions from
BPL devices. NTIA's studies to date indicate that such a problem could
occur only well in the future after hundreds of thousands or perhaps
millions of Access BPL devices are deployed. *See* Technical Appendix,
§4.

To further facilitate diagnosis of suspected BPL interference and
elimination of actual BPL interference, NTIA suggests that each BPL
operator be required to provide a single, telephone point of contact for
each deployment area in addition to the e-mail address NTIA suggests for
purposes of frequency coordination. The telephone point of contact
should be required to receive complaints of suspected interference and
be capable of accomplishing rapid diagnosis during the same telephone
session, or shortly thereafter, by a mutually agreed schedule.
Specifically, upon receipt of such a telephone call, the BPL operator
should perform or schedule a test in which the frequency(ies) of the
suspected BPL interference source(s) is (are) changed to determine
whether this test eliminates the interference. Alternatively, the BPL
operator could perform this test by briefly deactivating the suspected
BPL interference source(s) (*e.g.*, during a time of little or no
traffic on the BPL network element(s) involved). These simple, rapid
tests would determine whether the BPL operations are likely causing
interference. This requirement would enhance the utility of the proposed
shut-down and frequency agility capabilities and expedite resolution of
cases of actual interference. NTIA has sufficient evidence that shows
such a requirement is practicable and effective. In the course of
conducting BPL measurements, NTIA personnel requested shut-downs and
confirmations of BPL frequency usage via telephone and these requests
were executed in a matter of seconds under pre-arranged conditions.
Although such speedy responses may not be routinely practicable in
response to complaints of suspected interference, a requirement to be
capable of frequency shifts or shut-down of BPL network elements coupled
with the BPL operators\' incentives to preclude filings of interference
complaints with the Commission should yield prompt resolution of cases
of suspected BPL interference.

**V. NTIA RECOMMENDS CERTIFICATION BY ACCESS BPL OPERATORS**

**RATHER THAN VERIFICATION BY MANUFACTURERS TO ALIGN**

**AUTHORIZATION OBLIGATIONS AND BENEFITS WITH THE RESPONSIBLE PARTY**

NTIA recommends that Access BPL systems be authorized under the
Commission's certification procedures rather than verification
procedures as proposed in the BPL NPRM.[^21] Although many unintentional
emitters are subject to verification procedures, NTIA believes that
Access BPL devices pose interference risks that are among the highest of
the various kinds of authorized, unlicensed devices. Moreover, the
requisite compliance measurement guidelines are new and untried. NTIA
further recommends that authorizations for In-House BPL devices continue
to be granted to BPL equipment manufacturers upon verification but that
authorizations for Access BPL systems be granted to each qualified
operator rather than the Access device manufacturers.

Under the Part 15 framework, the device manufacturer is responsible for
compliance testing and the device operator is responsible for
eliminating any harmful interference the device may cause. This
divorcing of compliance testing and interference resolution
responsibilities is reasonable for devices that are marketed to the
general public and pose very low interference risk. However, all these
responsibilities should be aligned and placed on Access BPL operators
because they receive the BPL service revenue benefit and have strong
incentives to ensure that interference risks are properly limited and
technical standards are not violated. A somewhat analogous focus of
responsibilities is made for cable television systems.[^22] This
assignment of responsibilities should obviate the need for any special
labeling of Access BPL devices. Manufacturers of In-House BPL devices
should continue to be subject to Part 15 compliance measurements and
labeling requirements and receive the authorizations consistent with
current provisions of rule Parts 2 and 15.

Because Access BPL systems pose relatively high interference risks,
certification rather than verification should be required. Measurement
procedures being considered for Access BPL systems are new and unique.
Thus, the Commission should have the opportunity to review the
measurement reports that must be submitted with applications for
authorizations that are subject to certification. The Commission\'s
repository of measurement reports may help diagnose any systematic
interference that may arise from BPL systems, such as cases involving
particular power line configurations or specific types of devices;
however, NTIA's studies do not indicate that systematic interference
problems should be expected.

**VI. NTIA SUPPORTS THE COMMISSION\'S PROPOSED MEASUREMENT**

**GUIDELINES AND SUGGESTS ADDITIONAL STEPS TO FURTHER**

> **REDUCE INTERFERENCE RISKS**

The BPL Inquiry stated that existing Part 15 rules "...do not
specifically provide measurement procedures that apply to systems using
the power line as a transmission medium."[^23] NTIA\'s Phase 1 Study
showed that refinements, clarifications and adaptations of Part 15
compliance measurement provisions are needed for Access BPL systems to
reduce potential measurement inaccuracies and improve the validity of
results for all deployed BPL systems. Otherwise, the existing field
strength limits provide inadequate certainty that interference risks
will be confined to the levels allowed by the field strength limits and
other provisions. The Commission independently arrived at the same
conclusion and proposed a number of BPL compliance measurement
provisions that account for unique characteristics of BPL systems.[^24]
NTIA's understanding of key proposed revisions to measurement guidelines
and recommended refinements are presented below.

> A. A MEASUREMENT DISTANCE OF TEN METERS SHOULD BE USED
>
> WITH RESPECT TO OVERHEAD POWER LINES AND BPL DEVICES
>
> WITH A MODIFIED DISTANCE EXTRAPOLATION FACTOR

Part 15 specifications of different measurement distances for
frequencies below and above 30 MHz and, particularly, the thirty-meter
measurement distance specified for frequencies below 30 MHz present
logistical complications during *in situ* measurements. NTIA agrees and
endorses the Commission's solution to require a uniform measurement
distance of ten meters. However, NTIA\'s measurements and modeling
indicate that the change in BPL field strength with increasing distance
from the BPL device and power lines is not well approximated by the
existing Part 15 distance extrapolation factor.[^25] NTIA\'s recommended
solution to this anomaly is to uniformly apply a ten-meter standard
measurement distance, present explicit equivalent field strength limits
for those distances, and provide the appropriate distance extrapolation.
NTIA is further reviewing the Commission's proposal to utilize the
slant-path distance to the power line as a basis for extrapolation.[^26]

A ten-meter horizontal measurement distance already is specified for
Class A radiated emission limits (*i.e.*, for frequencies above 30 MHz),
and so, legacy measurements made at this distance will remain useful.
Establishing this same measurement distance uniformly for other Access
BPL limits will ease the measurement burden by eliminating two other
measurement

distances for BPL systems. This logistical easement will enable better
focus on other, more complicated measurement provisions that may
introduce new burdens. Moreover, a ten-meter measurement distance
appears to satisfy important criteria of safety, measurement
sensitivity, and avoidance of misinterpretation of local field strength
peaks as being the overall peak emission level. While field strength can
fall and increase with increasing distance well beyond the recommended
ten-meter measurement distance, the overall peak level consistently
occurs at one or more locations within ten meters of the power lines and
BPL device. Secondary local field strength peaks further than ten meters
from the power lines and Access BPL devices generally are substantially
lower than the overall peak; hence, they will pose substantially less
interference risk than arises at locations where field strengths are
near the limiting value.

The BPL NPRM proposes to allow measurement at a horizontal distance of
three meters in cases where a ten-meter measurement distance is not
practicable. NTIA agrees that alternative measurement distances should
be permitted and utilized when necessary. NTIA further recommends that
specific field strength limits should be specified for the ten-meter
measurement distance at all permissible BPL operating frequencies. In
other words, the new BPL rules will have already applied appropriate
distance extrapolations in the specification of equivalent field
strength limits at the new ten-meter measurement distance. NTIA is
developing equivalent field strength limits and distance extrapolation
factors on the basis of the radiation and propagation properties of
Access BPL emissions and will provide its findings as soon as possible.

B. MEASUREMENTS SHOULD FULLY ADDRESS RADIATION FROM BPL

> DEVICES AND POWER LINES TO WHICH THEY ARE CONNECTED

Certain Part 15 provisions require that measurements be made on radials
emanating from the device under test, which assumes that the device
under test is the radiating element generating peak levels of field
strength.[^27] However, NTIA measurements and analyses show that in most
cases, peak field strength levels are not centered on the BPL device and
multiple segments of the power lines and impedance discontinuities are
the most significant BPL signal radiating elements.[^28] Thus, BPL
compliance measurements should address both the BPL device and the power
lines to which it is connected.

NTIA\'s BPL measurements discovered that the peak BPL field strength is
not necessarily located at the BPL device. This unusual phenomenon was
confirmed and further investigated by evaluating numerous models of BPL
devices and power lines using the Numerical Electromagnetic Code
(\"NEC\") to predict radiated fields. For the case of a two-meter high,
horizontally polarized measurement antenna that is oriented parallel to
the power lines (*i.e.*, a typical height for land mobile receiver
antennas), NEC analysis of simple power line models shows the peak
electric field to be centered at or near the BPL power line coupler.
However, when the same horizontally polarized measurement antenna is
reoriented to be perpendicular to the power lines, NEC shows multiple
peaks of BPL electric field strength occurring at locations tens of feet
from the power lines and BPL devices. Peak vertically polarized electric
fields at a height of two meters occur at several locations under power
lines at various distances from the BPL device.

NTIA\'s further analysis of radiated emissions from overhead Access BPL
systems shows that relatively high emissions can occur at various
distances from the BPL device along the power line, in some cases at
regular distance intervals. *See* Technical Appendix, §3. The peak field
strength level can occur at any fraction or multiple of a wavelength
from the BPL emitter.

Thus, the proposed Access BPL measurements at distances of 0, 1/4, 1/2,
3/4 and 1 wavelength along the power line from the BPL emitter may not
consistently reveal the peak level of radiated emissions. NTIA
recommends a comprehensive search for the overall peak field strength at
the one-meter measurement height along key segments of the power lines
at the specified horizontal measurement distance. This should not amount
to an undue measurement burden insofar as local peaks of field strength
often occur at regular distance intervals along the power line and
measurement personnel will be able to fairly quickly identify the
location of peak field strength. NTIA is further studying field strength
trends along the power lines and intends to provide additional
guidelines to facilitate identification of the peak field strength and
its location (*i.e.*, the key power line segments where the peak is
likely to be found). However, this proceeding should not await
development of such guidelines because their purpose is to ease
measurement burdens rather than establish fundamental requirements.

> C. MEASUREMENT ANTENNA HEIGHT SHOULD BE ONE METER AND
>
> A 5 dB HEIGHT CORRECTION FACTOR SHOULD BE APPLIED

Measurements must ensure BPL compliance with field strength limits in
all directions of radiation associated with the most likely cases of
potential interference, including rooftop locations higher than power
lines.[^29] Conceptually, this can be accomplished either through direct
measurement at various heights and directions or by application of a
standard measurement antenna height with an adjustment factor that
accounts for other heights. NTIA concurs with the Commission's proposed
one-meter antenna measurement height even though the vast majority of
radio receiver antennas used by the federal government are two meters or
higher above the ground (*e.g.*, vehicles, building roofs, towers, and
aircraft). The existing Part 15 and American National Standards
Institute standard measurement antenna height of one meter is associated
with compliance measurements at an open air test site (\"OATS\") at
which associated ground reflection effects are controlled and have been
factored in calibration of signal propagation and measurement antenna
gain, but the one meter height can be reliably used with a height
correction factor outside of the pristine OATS environment.

NTIA\'s assessment of the relationship between field strength from
overhead Access BPL systems and measurement height above ground level
has confirmed that peak field strength often occurs near the height of
the power lines carrying BPL signals. *See* Technical Appendix, §2.
However, the peak BPL field strength can occur at other heights well
below and above the power line, and there is no clear, consistent trend
with frequency or other parameters that may guide measurement personnel.
In apparent recognition of this phenomenon, the Commission proposes to
vary measurement antenna height between one and four meters at
frequencies above 30 MHz as is the norm for compliance testing at an
Open Air Test Site. Rather than require a measurement search for the
peak BPL field strength in both height and distance along the power
line, however, NTIA believes that measurement height should be addressed
using a height correction factor. NTIA's analysis shows that a 5 dB
height correction factor used in connection with measurements at a
one-meter height would fulfill this goal.

Using NEC models, NTIA has evaluated the distributions of heights and
magnitudes of peak field strength from over one-thousand combinations of
nineteen power line configurations, polarization and location, at each
of twenty-five BPL operating frequencies. This analysis reveals that 80
percent of the local field strength peaks at any height will be within 5
dB of the peak electric field strength measured along the power line at
a height of one meter. In the large number of potential cases modeled by
NTIA, the field strength at any polarization exceeds the peak value
measured one-meter height by up to 20 dB in small spatial regions. Use
of the 80 percentile value of 5 dB rather than the 100 percentile value
of about 20 dB avoids undue constraint on BPL systems without
significant impact on interference risks. Thus, NTIA recommends that at
all frequencies, the peak field strength should be estimated to be 5 dB
higher than the peak value measured along the power line at one-meter
height. NTIA further recommends that for each representative BPL
deployment, the locations and magnitudes of the six highest field
strength levels measured at one meter height (plus 5 dB height
correction factor) be recorded in the measurement report for overhead
Access BPL systems.

> D. ALL BPL OPERATING FREQUENCIES SHOULD BE CONSIDERED
>
> AND BPL EQUIPMENT SHOULD INCORPORATE THE
>
> NECESSARY OPERATIONAL POWER CONSTRAINTS

Existing Part 15 measurement guidelines generally are tailored for
devices that operate at fixed frequencies or have uniform emission
characteristics over the tuning range of the device. However, Access BPL
systems have, or should have the frequency agility proposed in the NPRM.
Access BPL radiation characteristics are not uniform across all possible
operating frequencies. Thus, to properly address frequency-selective
radiation characteristics, measurements should be made sequentially with
the Access BPL devices operating at all frequencies at which they are
capable.[^30] This should be accomplished using the maximum possible BPL
device output power and operational duty factor. In the event that the
applicable limit is exceeded during measurements, the results of all *in
situ* measurements at three representative sites at a given operating
frequency may be adjusted downward by the difference between maximum
output power and the maximum compliant power level that will be used
operationally at that frequency.[^31] Consistent with §15.15(b), the
Access BPL equipment should be modified to prevent inadvertent Access
BPL operation at power levels that may result in field strength that
exceeds the applicable limits.

> E. MEASUREMENTS BELOW 30 MHz SHOULD USE A CALIBRATED
>
> LOOP ANTENNA WITH AN APPROPRIATE MAGNETIC-TO-ELECTRIC
>
> FIELD CONVERSION FACTOR AND AN ELECTRIC FIELD ANTENNA SHOULD BE USED
> ABOVE 30 MHz

NTIA is continuing to study the conversion between levels of magnetic
field strength measured with a shielded loop antenna and electric field
strength when measurements are performed at a horizontal distance of ten
meters. In the far-field of a radiated emission, the ratio of
electric-to-magnetic field strength (*i.e.*, wave impedance) is 377
ohms.[^32] However, in the near field, such as at the ten-meter
recommended measurement distance, NTIA's work to date indicates that
wave impedance may vary from 1 ohm to over 2,000 ohms at various
locations. NTIA's on-going study of wave impedance is focusing on the
six measurement locations where electric field strength is highest and
it is not yet clear whether the magnetic-to-electric field strength
conversion factor will differ significantly from the presently assumed
value of 377 ohms. NTIA will report its analysis findings as soon as
possible insofar as this conversion factor should be codified in this
proceeding.

> F. REPRESENTATIVE POWER LINES USED FOR BPL MEASUREMENTS SHOULD BE
> CAREFULLY SELECTED TO ENSURE THAT PEAK EMISSIONS ARE MEASURED

In light of the highly varied parameters and radiation properties of
power lines, compliance measurements should address BPL devices
installed on power lines that yield the highest levels of field
strength. One or more highly-reflective impedance discontinuities likely
should be included in the power lines at various distances from the BPL
coupling point in order to ensure that all important standing wave
conditions are generated at all frequencies.[^33] NTIA is continuing its
studies to identify power line features that cause the highest levels of
field strength and believes that the results need not be presented in
rules, *per se*. The findings of this study will provide guidelines
rather than basic regulatory infrastructure.

> G. CERTAIN ADDITIONAL MEASUREMENT PROVISIONS SUCH AS MEASUREMENT
> BANDWIDTH SHOULD BE MANDATORY FOR BPL

In the framework of Part 15, many compliance measurement provisions are
cast as guidelines and within these guidelines certain ANSI and CISPR
measurement procedures are incorporated by reference.[^34] For example,
a requirement to use a quasi-peak detector is specified as a rule, but
the measurement bandwidth is two levels removed from rule status by
virtue of incorporation by reference from guidelines. NTIA believes that
the measurement bandwidth should be specified as a rule for BPL,
specifically 9 kHz bandwidth at frequencies below 30 MHz and 120 kHz
bandwidth at frequencies above 30 MHz. Likewise, use of the above
recommended measurement height correction factor and limits for three-
and ten-meter measurement distances should be embodied as rules. NTIA
believes that the BPL compliance measurement provisions deemed most
important to limitation of interference risks should be

codified as rules rather than guidelines.

> H. SPECTRAL POWER DISTRIBUTIONS OF BPL EMISSIONS SHOULD BE
>
> MEASURED AND INCLUDED IN THE MEASUREMENT REPORT

In the course of its BPL measurement campaigns, using a spectrum
analyzer, NTIA was able to quickly distinguish Access BPL emissions from
other signals and noise by virtue of advance knowledge of the BPL system
modulation and multiple access parameters but no knowledge of the
operating frequencies. Identification of In-House and Access BPL signals
could be further facilitated by inclusion of measured spectral power
distributions in the compliance measurement report, and such data may
provide other unforeseen benefits. This will assist interference
diagnosis independently of adjustments to the BPL system. However, as
stated earlier, positive identification of BPL interference can be
readily accomplished via telephone with the radio operator, and
remote-control adjustment of BPL system frequency usage or a brief
shut-down of BPL network elements. NTIA does not expect that any radio
operator will ever need to diagnose suspected interference from BPL
systems because this is the responsibility of the BPL operators.

**VII. ACCESS BPL MAY WARRANT ITS OWN RULE PART OR SUB-PART OF PART 15**

NTIA suggests presentation of Access BPL rules in a new, dedicated rule
part because weaving the appropriate Access BPL provisions into Part 15
may yield unclear, confusing rules.[^35] Under similar circumstances,
the Commission established technical rules for cable television systems
in a new rule part.[^36] The rules proposed in the BPL NPRM and the
additional

Access BPL provisions recommended in this pleading are substantial. Many
of these rules are unique to Access BPL and others derive from existing
rules with special adaptation:

-   Certification by the Access BPL operator rather than the
    manufacturer is inconsistent with Part 15.

-   Access BPL amounts to a service, and as such, many of the
    contemplated technical rules could be viewed as service requirements
    that are inconsistent with the scope of Part 15.

-   Coordination procedures, coordination areas, excluded bands or
    exclusion zones needed for Access BPL are not presently specified in
    Part 15.

-   BPL equipage requirements for power control, frequency tuning and
    notching, and shut-down are not presented in Part 15.

-   Procedural requirements for elimination of interference from Access
    BPL systems do not exist in Part 15 rules for unintentional
    emitters.

-   Certain Part 15 provisions should not be applied to Access BPL
    (*e.g.*, measurement on radials from the device under test,
    §15.31(f)(5)).

-   Specifications of the BPL operator notification requirements are
    more detailed than those in Part 15 for power line carrier systems.

-   Many new and substantially modified measurement provisions should be
    specified as rules for Access BPL:

    -   a uniform ten-meter measurement distance, perhaps with a
        three-meter option, rather than various distances at different
        frequencies;

    -   a 5 dB height correction factor;

    -   measurement with the Access BPL system operating at all
        frequencies at which it is capable of operating;

    -   interpretation of *in situ* measurement results from 3
        representative sites;

    -   magnetic-to-electric field strength conversion factor for
        near-field measurements at frequencies below 30 MHz;

    -   specification of equivalent field strength limits for ten- and
        perhaps three-meters in lieu of distance extrapolations;

    -   measurement of spectral power distributions;

    -   specification of measurement bandwidths.

**VIII. FURTHER REGULATORY ACTION MAY BE NEEDED AFTER**

**ADDITIONAL STUDIES ARE COMPLETED AND ADDITIONAL**

**EXPERIENCE IS GARNERED.**

NTIA believes that the In-House and LV/MV Access BPL rules proposed in
the BPL NPRM and recommended by NTIA constitute an appropriate basis for
rulemaking at this time. The Commission has authorized Access BPL
operations only under experimental licenses even through existing rules
for carrier current systems accommodate BPL. As the rulemaking drew
closer, the Commission ceased granting geographically unlimited BPL
experimental licenses. Now, it is time to adopt rules that will enable
development and implementation of In-House and LV/MV Access BPL that are
compatible with radio communications.

Other potential BPL issues can be revisited under future actions, if
necessary. The BPL NPRM notes that In-House BPL measurement guidelines
should be updated if warranted based on studies by the International
Special Committee on Radio Interference ("CISPR"). NTIA has not studied
Access BPL using HV transmission lines. In the interim, based on
expressed frequency preferences and available studies, the In-House and
Access BPL operating frequency range should be limited to 1,705 kHz to
80 MHz (minus excluded bands and areas).[^37] Oversight of potential
future ionospheric interference is needed, but NTIA concludes that this
interference could occur only in the long-term and NTIA intends to
monitor BPL deployment in order to predict the potential onset of such
problems.

**IX. CONCLUSION**

NTIA recommends a number of refinements to the modified rules proposed
for BPL systems and believes that the Commission's proposals as
extrapolated herein will fully alleviate the concerns of all parties to
this proceeding. NTIA believes that these rules will prove to provide a
reasonable and safe approach to reducing interference risks from BPL
systems and expediting effective provisions for elimination of
interference from BPL systems. Because these

proposed rule modifications effect reductions in on-going interference
risks, they should be placed into effect as soon as possible. Moreover,
these rules create an environment in which BPL proponents can properly
gauge investment risks and fulfill the protection requirements of radio
communications.

Respectfully submitted,

+-----------------------------------+-----------------------------------+
| Michael D. Gallagher              | Kathy Smith                       |
|                                   |                                   |
| Acting Assistant Secretary for    | Chief Counsel                     |
|                                   |                                   |
| Communications and Information    | National Telecommunications and   |
|                                   |                                   |
| Fredrick R. Wentland              | Information Administration        |
|                                   |                                   |
| Associate Administrator           | U.S. Department of Commerce       |
|                                   |                                   |
| Office of Spectrum Management     | Room 4713                         |
|                                   |                                   |
| Thomas Sullivan                   | 1401 Constitution Avenue, N.W     |
|                                   |                                   |
| Edward Drocella                   | Washington, DC 20230              |
|                                   |                                   |
| Electronics Engineers             | \(202\) 482-1816                  |
|                                   |                                   |
| Office of Spectrum Management     |                                   |
+-----------------------------------+-----------------------------------+
|                                   |                                   |
+-----------------------------------+-----------------------------------+

June 4, 2004

[^1]: President George W. Bush, Remarks at the American Association of
    Community Colleges Annual Convention, Minneapolis Convention Center,
    Minneapolis, Minnesota (April 26, 2004) (available at
    http://www.whitehouse.gov/news/releases/2004/20040426-6.html).

[^2]: Amendment of Part 15 regarding new requirements and measurement
    guidelines for Access Broadband over Power Line Systems, ET Docket
    04-37, Notice of Proposed Rulemaking, FCC 04-29, released February
    23, 2004, ("BPL NPRM").

[^3]: "Potential Interference From Broadband Over Power Line (BPL)
    Systems To Federal Government Radiocommunications at 1.7 -- 80 MHz,"
    NTIA Report 04-413, April 2004 ("NTIA Phase 1 study"). Available for
    download at NTIA's web site, URL: www.ntia.doc.gov.

[^4]: *Inquiry Regarding Carrier Current Systems, including Broadband
    over Power Line Systems*, ET Docket 03-104, released April 28, 2003
    ("BPL Inquiry").

[^5]: Devices authorized under Part 15 of the Commission's Rules
    generally are capable of causing harmful interference when
    concurrently operating with a co-located, co-frequency radio
    receiver. The rule provides that "\[p\]arties responsible for
    equipment compliance should note that the limits specified in this
    part will not prevent harmful interference under all circumstances."
    47 CFR 15.15(c).

[^6]: NTIA refers to suspected interference because in many cases,
    degradation of reception is the result of problems in the receiver,
    its antenna, or the interconnecting transmission line. For example,
    rodents sometimes chew coaxial cables or twin-lead transmission
    lines and cause significant reductions or complete loss of the
    desired signal power that should reach the receiver. In many other
    cases, interference is realized but not caused by the suspected
    device.

[^7]: BPL NPRM, at ¶47.

[^8]: BPL NPRM, at ¶32 and Appendix B, ¶2.

[^9]: BPL NPRM, at ¶¶1, 3, and 10-13.

[^10]: In Comments in response to the BPL Inquiry (July 7, 2003), ARRL
    argues that "\[p\]ower line noise is the single most frequently
    identified source of HF interference to licensed Amateur Radio
    operators." ARRL Comments at ¶3. In Comments in response to the BPL
    Inquiry (July 7, 2003), Ambient Corporation states "\[i\]n the
    absence of BPL, noisy power lines may create interference with
    existing spectrum uses." Ambient Corporation Comments at 9.

[^11]: *See, e.g*., Comments in response to the BPL Inquiry of: Joseph
    Hance, February 28, 2004, at ¶1; Donald T. Lane, February 20, 2004,
    at ¶1; Richard Casey, February 27, 2004, at ¶2; David Norris, March
    1, 2004, at ¶3.

[^12]: David Tobenkin, Comments at 9 (December 24, 2003).

[^13]: BPL NPRM, at ¶33 and Appendix B, ¶4.

[^14]: NTIA BPL Phase 1 study, §7.12, and Technical Appendix, at §§2, 3
    and 5.

[^15]: *See* Phase 1 study, §4.6. The NRQZ exists to protect
    radioastronomy operations at Green Bank, West Virginia. *See* 47 CFR
    21.113. Spectrum management authorities of the NRQZ already enjoy
    excellent rapport with the local electric utility operator for the
    cooperative elimination of power line noise. Intentional emissions
    by Part 15 devices are forbidden at 2173.5 - 2190.5 kHz in order to
    protect maritime and aeronautical distress alerting and other safety
    communications. *See* 47 CFR 15.205. Although BPL radiated emissions
    are unintentional, distress and safety communications in the
    2173.5-2190.5 kHz band must be possible using the weakest, barely
    intelligible signals that are highly vulnerable to interference. The
    ILS system is an aeronautical radionavigation system. By definition,
    \"harmful interference\" is \"\[i\]nterference which endangers the
    functioning of a radionavigation service or of other safety
    services\...\" and the interference risks posed by BPL systems
    constitute such endangerment. 47 CFR 2.1.

[^16]: Conditions for revocation of equipment authorizations are
    specified in 47 CFR 2.939.

[^17]: BPL NPRM at ¶¶40 - 42 and Appendix B, ¶4.

[^18]: BPL NPRM at ¶43 and Appendix B, ¶4.

[^19]: A mobile receiver operating via ionospheric signal propagation
    can be located virtually anywhere relative to a base station or
    other mobile stations with which it is communicating.

[^20]: When applied with appropriate distance separation guidelines for
    co-frequency BPL and radio operations, the BPL operator can
    determine frequency plans for Access BPL network elements that avoid
    certain locally used radio frequencies where necessary to prevent
    interference.

[^21]: Certification procedures and requirements are specified in 47 CFR
    2.1031-1057 and 15.101.

[^22]: Ideal coaxial cable TV distribution systems are not expected to
    radiate emissions; however, actual cable systems unintentionally
    radiate emissions from faulty connections, unauthorized cable
    set-top boxes, points where cable or amplifier shielding is poor,
    and improper cable terminations. Cable set top boxes are subject to
    manufacturer Declaration of Conformity as specified in 47 CFR 15 and
    the balance of the cable distribution system is subject to operator
    measurement under Part 76.

[^23]: BPL Inquiry at ¶2.

[^24]: BPL NPRM at ¶¶ 45-47 and Appendix C.

[^25]: 47 CFR 15.31(f) applies 20 dB and 40 dB per decade distance
    extrapolation factors to adjust field strength measured at a
    distance other than the specified measurement distance.

[^26]: BPL NPRM at ¶46.

[^27]: 47 CFR 15.31(f)(5)

[^28]: *See* NTIA Phase 1 study, §5 and Appendixes D and E.

[^29]: Many radio receivers operating in the 1.7-80 MHz frequency range
    use antennas located at or above the heights of local power lines.
    Compliance with field strength limits at and above the power line
    height also controls the composite interfering signal level
    generated at distant receivers by ionospheric propagation of
    unintentional emissions from widely deployed BPL devices. This
    mechanism is being investigated in phase 2 of NTIA\'s studies.

[^30]: ^?^ For example, a BPL system that has 5 MHz bandwidth and can be
    tuned between 5 MHz and 30 MHz would be measured while tuned to 5
    MHz, 10 MHz, 15 MHz...and 30 MHz. This principle should not be
    confused with the requirement to adjust measurement frequencies
    throughout frequency ranges specified in §15.33.

[^31]: ^?^ The requirement to perform *in situ* compliance measurements
    at three representative deployment sites should specify how the
    results are to be applied in order to achieve compliance with field
    strength limits.

[^32]: For example, consistent with "Ohms Law," to convert a measured
    magnetic field strength in dBµA/m to an associated electric field
    strength in dBµV/m in the far filed region, one would add 20 log
    (377 ohms), or 51.2 dB, to the measured magnetic field strength.

[^33]: *See* NTIA Phase 1 study, §§7.2 and 7.9, which provide a degree
    of guidance.

[^34]: *See*, *e.g.*, 47 CFR 15.35.

[^35]: Rules for In-House BPL should be established in Part 15 as
    suggested by the BPL NPRM.

[^36]: 47 CFR 76. Like Access BPL systems, cable television systems are
    unintentional radiators. Ideal cable systems radiate no emissions
    and imperfections result in signal leakage. In sharp contrast, ideal
    Access BPL systems radiate emissions, endemically, albeit
    unintentionally.

[^37]: Experimental licenses granted Access BPL use of 1.7-80 MHz and
    NTIA studied BPL only in that frequency range. Interference risks
    exist from xDSL and Cable TV at other frequencies, potentially
    complicating diagnosis and elimination of interference from BPL
    systems.