Copyright 2000 Federal News Service, Inc.
Federal News Service
February 17, 2000, Thursday
SECTION: PREPARED TESTIMONY
LENGTH: 4024 words
HEADLINE:
PREPARED TESTIMONY OF BRUCE A. FRANCA DEPUTY CHIEF OFFICE OF ENGINEERING AND
TECHNOLOGY FEDERAL COMMUNICATIONS COMMISSION
BEFORE THE
HOUSE COMMERCE COMMITTEE TELECOMMUNICATIONS & FINANCE
SUBCOMMITTEE
SUBJECT - COMMERCE ON SPECTRUM INTEGRITY AND HR
3439, THE "RADIO BROADCASTING PRESERVATION ACT OF 1999".
BODY:
Mr. Chairman and Members of the
Subcommittee. thank you for the opportunity to appear before you today to
discuss the FCC's spectrum management responsibilities and the Commission's
recent decision to authorize low power FM (LPFM) stations.
The FCC's Spectrum Management Responsibilities
I would like to
begin with an overview of the Commission's role in managing the radio spectrum.
Under Section 303 of the Communications Act, which defines the general powers of
the agency, the FCC is tasked with assigning bands of radio frequencies to the
various classes of stations, assigning frequencies and power for individual
stations, and specifying the locations where classes of stations or individual
stations may operate. In addition. Section 7 of the Communications Act states:
"(I)t shall be the policy of the United States to encourage the provision of new
technologies and services to the public." Effective management of the radio
spectrum is therefore a core responsibility of the FCC. Spectrum is a valuable
and finite public resource that must be allocated and assigned in a manner that
will provide the greatest possible benefit to the American public. Consistent
with the FCC's statutory obligations, we view our mission in the Office of
Engineering and Technology (OET) as ensuring that the radio spectrum is used
efficiently and effectively. One of our principle jobs is to help to define
policies that maximize the efficient use of the spectrum and promote the
introduction of new services and technologies. OET, for example, developed the
allocation plans for cellular and PCS wireless communications services and for
digital television service.Over time, technological advances, growth in user
demand, and the finite nature of spectrum have made our spectrum management
responsibilities increasingly complex. -To address the continuing growth of
demand for radio services, we have focused our approach to spectrum management
on allowing spectrum markets to make more efficient use of frequency bands
through new technologies and on increasing the amount of spectrum available for
use. In addition, we have sought to encourage the development and deployment of
new, more spectrum-efficient technologies that will increase the amount of
information that can be transmitted in a given amount of bandwidth and to allow
greater use of the spectrum occupied by existing services wherever possible.
Under this approach, new services have been implemented either through
sharing with existing operations or through reallocation of spectrum from
existing services to new services and technologies. In this regard, we have, for
example, developed plans for sharing between satellite and terrestrial fixed
services and for recovery of spectrum from existing uses to make way for new
technologies. The spectrum used for PCS service at 2 GHz was recovered from
fixed microwave services that were relocated to higher bands. In addition, the
efficiency of the digital television transmission standard has made it possible
to plan for the reallocation of the 108 MHz of spectrum now used for television
channels 52-69 to new public safety, commercial wireless, and broadcast
services.Low Power FM Radio
I next will discuss the
Commission's decision to allow the operation of low power FM
stations. In its January 20, 2000, Report and Order in MM Docket No. 99-25, the
Commission authorized the licensing of two new classes of low power radio
stations -one operating at a maximum power of 100 watts and the other at a
maximum power of 10 watts. The new LPFM stations will be licensed to operate on
a noncommercial educational basis only, and to parties that do not hold an
attributable interest in any other broadcast station or media. The rules also
provide for a significant preference to locally based applicants.
The
Commission has taken a conservative approach in protecting existing FM service.
For example, the Commission did not adopt its original proposals to permit 1000
watt, commercial LPFM stations and to allow LPFM operations on 2nd adjacent
channels. In addition to specifying low power operation, the
rules provide a number of other safeguards to protect existing
FM stations, such as limitations on antenna height and
separation requirements for low power stations with respect to
full power stations operating on the same channel, on 1st and 2nd adjacent
channels, and on intermediate frequency channels. We also added a 20 km buffer
to the required separation distances between LPFM and full service stations that
are operating on co- and 1st adjacent channels. This buffer will provide an
additional margin of protection for full power stations that modify or upgrade
their facilities.We did not, however, impose requirements for separation of LPFM
stations' from stations on 3rd adjacent channels. From the considerable
technical record in our proceeding, we found that LPFM operation on 3rd adjacent
channels will not result in significant new interference to the service of
existing FM stations. Our discussions with, and comments from, proponents of new
digital radio technologies also indicate that LPFM operations on 3rd adjacent
channels will not impact potential future digital services in the FM band.
(See attached illustration of 1st, 2nd and 3rd adjacent channels on the
FM radio dial.)
Our decision in this matter followed a nearly one-year
long public comment period extended four times between January and November
1999. We granted these four extensions at the request of the broadcasting
industry, at times over the strong opposition of other parties in the
proceeding. We did so to give broadcasters and all other parties a more than
ample opportunity to comment on the proposed LPFM service. During this lengthy
comment period the Commission received significant expressions of interest and
public support for LPFM service. The Commission received comments and letters
from thousands of individuals and groups seeking licenses for new radio
stations. These comments -- from churches or other religious organizations,
schools, colleges, students, community organizations, musicians and other
citizens -- reflected a broad interest in, and need for, service from highly
local radio stations that are strongly grounded in their communities. The plan
for LPFM service adopted by the Commission will address these needs by enhancing
listeners' access to locally focused, community- oriented radio broadcasting.
In providing for the operation of LPFM radio stations, we have followed
the principles of our general approach to spectrum management: the new LPFM
stations will share the FM radio spectrum with existing stations, thereby making
more efficient use of the FM band. In establishing this service, the Commission
was also following two longstanding foundation principles under Section 307(b)
of the Communications Act in providing spectrum for broadcast use. The first is
to promote a diversity of media voices. The second is to adopt policies that
facilitate and encourage the operation of broadcast services that meet local
needs and specialized interests wherever possible. Consistent with these
principles, the Commission's first goal in establishing a new LPFM service was
to create a class of radio stations that would serve very localized communities
or underrepresented groups within communities. This new service will enhance
service to the public by providing service opportunities for parties who had
previously been denied access to broadcast spectrum.
A second,
specific, goal was that the LPFM service include the voices of community-based
schools, churches, and civic organizations.
The Commission in planning
for the LPFM service also emphasized that it would not compromise the integrity
of the FM radio spectrum. The Commission was particularly cognizant of the
concerns of FM broadcasters with regard to both existing service and possible
options for FM stations to provide digital service. Addressing these concerns,
the Commission stated that it was determined "to preserve the integrity and
technical excellence of existing FM radio service, and not to impede its
transition to a digital future." In this regard, the principal technical issues
in this proceeding have been the potential for new low power
stations to cause interference to existing FM radio service and
to impact future digital radio technologies, such as In- Band On-Channel, or
"IBOC," systems. Based on our own technical studies and analyses of studies by a
number of others, we are convinced that LPFM service, as provided under the new
rules, will not adversely impact reception of full service FM stations, nor will
it affect the transition of these stations to digital service using IBOC
technology that transmits digital signals on adjacent channels.
Third
Adjacent Channel Protection Is Not Necessary
Of course, I am aware of
the differences of opinion that exist, particularly on the part of full service
FM stations and their representatives, over whether LPFM stations will cause
interference to existing FM service. The principle issue here is over whether we
should have imposed 3rd adjacent channel restrictions on LPFM stations. The main
determinative factor is the ability of FM receivers to operate satisfactorily
when signals from LPFM stations are present on 3rd adjacent channels. I believe
that the record provides strong support that 3rd adjacent channel restrictions
are not needed for LPFM and that any areas experiencing interference would be
very small and would be outweighed by the benefits of the new service.
Initially, I would point out that during the period from 1964 to 1987,
pre-1964, "grandfathered." short-spaced full power FM stations were permitted to
modify their facilities without regard to either 2nd or 3rd adjacent channel
spacings. No interference complaints were received as a result of such
modifications, and this policy was re- instituted in 1997, again without
subsequent interference complaints. Similarly. in 1991, the Commission decided
to accept small amounts of potential 2nd and 3rd adjacent channel interference
in the noncommercial FM service where such interference is counterbalanced by
substantial service gains.
Technical Studies
In addition to
these historical precedents, the technical data submitted in the proceeding also
supports the conclusion that 3rd adjacent channel restrictions are not needed to
protect full service FM stations from LPFM operations. As you are aware, three
technical studies of FM receivers were filed in response to the Commission's
Notice of Proposed Rule Making. These studies were submitted by the Consumer
Electronics Association (CEA), the National Association of Broadcasters (NAB).
and the National Lawyers Guild (NLG).1 In addition, our Office conducted its own
study of a sample of 21 FM receivers. Taken together, the studies examined 75
consumer FM radios of various types and performance capabilities, including
automobile radios, component tuners or receivers, portable radios such as "boom
boxes." personal radios such as "Walkman" type units, and clock radios. Finally,
the NAB and CEA filed supplementary technical information in their reply
comments, and the Media Access Project submitted in its reply comments a
Technical Analysis of the Low Power FM Service prepared by
Professor Theodore Rappaport, James S. Tucker Professor of Electrical
Engineering, Virginia Tech, and Chairman, Wireless Valley Communications. Inc.,
Blacksburg, Va.
These studies provide a substantial body of information
on FM receiver performance in the presence of interfering signals.
Unfortunately. the studies used different methodologies that make direct
comparisons between them difficult. However, as the NAB stated in its reply
comments, the significant differences among the studies were not in the
measurements or in the performance of the radio receivers tested, but rather, in
the definition of impaired reception. We generally concur with that assessment
and believe that the most significant differences in the conclusions of these
studies are the result of variations in the definitions of desired service and
when the desired service is impaired.
-NAB/CEA Criteria Are
Inappropriate for Today's FM Service
Both CEA and NAB, for example,
generally find the performance of today's FM radios unacceptable because they do
not meet their presupposed desired levels of performance. For example. 17 of the
28 radios tested by the NAB failed to meet its standard of 50 dB audio
signal-to-noise ratio (S/N) performance with no interference present and with
the "strongest" desired signal level tested? Similarly. CEA reports that none of
its sample receivers "came near meeting" its 45 dB S/N performance target at the
current FCC protection standards for full power co-channel stations. While such
performance levels may indicate more interference from prospective LPFM
stations, we fail to see how such levels can be appropriate measures when most
radios do not perform to these levels, even in the absence of any interference,
as was the case in NAB's tests.
Moreover, we have seen no indication
from consumers that they find that the vast majority of FM receivers do not
provide satisfactory service. Therefore, as stated in our Report and Order, we
do not find the S/N levels suggested by CEA or NAB to be appropriate
interference criteria for today's FM radio service. We also note that a previous
study by the NAB indicated that the current FCC co-channel protection
requirement for FM stereo yields an audio S/N of about 30 dB, not the 50 dB
suggested by NAB in its technical study.3
- Receivers Are Better at
Rejecting 3rd Adjacent Channel Interference
Notwithstanding the
differences among the technical studies regarding performance standards, there
are important consistencies in the stud,,' results that we find support a
conclusion that 3rd adjacent channel restrictions are not needed for LPFM
stations. All four studies show' that the ability of FM radios to reject
interference from signals on a 3rd adjacent channel is generally much better
than from interference from signals on a 2nd adjacent channel. This is to be
expected since 3rd adjacent channel is further removed from the desired channel
to which you are tuning. (See again the attached illustration.)
The OET
and NLG studies generally conclude that FM receivers provide for adequate
rejection of interference on 2nd and 3rd adjacent channels. The OET study, for
example, finds that nearly all of our receivers appear to meet the 2nd adjacent
channel protection criteria and exceed the 3rd adjacent protection criteria by
about 8-10 dB. a wide margin. While CEA and NAB argue that their studies show
that the adjacent channel protections should be retained, a review of CEA's
results shows that its median receiver provides about -40 dB of rejection of 3rd
adjacent channel interference, and that this margin of performance is about 3 to
7 dB better than 2nd adjacent performance for its sample. Similarly. the NAB
tests also show 3rd adjacent channel performance to be substantially better than
2"d adjacent -- on the order of 8 to 10 dB. This means that radios can generally
reject signals on a 3rd adjacent channel that are about six to ten times
stronger than signals on 2nd adjacent channels.
The studies also found
that automobile radios and home stereo/component receivers tend to be more
effective at rejecting adjacent channel interference than clock, personal and
portable radios. Our examination of the studies indicates that automobile radios
and home stereo/component receivers generally are able to provide -40 dB or more
rejection of 3rd adjacent channel signals and therefore generally will provide
acceptable service in the absence of 3rd adjacent channel protection. NAB's test
results, for example, show that FM radios in automobiles, where most FM
listening is done, meet the current -40 dB criteria.
We also recognize
that poorer quality receivers, such as personal and clock radios, may experience
some additional interference as a result of eliminating the 3rd adjacent channel
protection for LPFM stations.
We note, however, that these classes of
radio may also experience some degree of interference from co- and 1st adjacent
channel full power FM stations operating within the existing protection
requirements. We also believe that consumers generally understand that there are
performance differences among the classes of radios and that they accept the
fact that lower cost radios may provide more limited service capabilities. We
therefore believe that our decisions with regard to LPFM service should not be
constrained solely by the performance limitations of lower cost radios any more
than we should use those radios to redefine existing FM radio service.
For example, if we were to define acceptable FM radio service
using NAB's performance measure and NAB's median test results for personal
radios - the radius of a 6 kilowatt Class A radio station's protected service
area would go from 27.5 km to less than 10 km. This is because such radios do
not provide acceptable service as defined by NAB beyond about 10 kin. even in
the absence of any interference. I do not believe that this is a realistic
approach, as this would ignore service provided to radios that provide more
typical performance, and would unfairly reduce the station's expected audience
reach.
Potential Interference from LPFM is Small
We also found
that the area in which any additional interference would be likely to occur from
an LPFM station operating on a third adjacent channel at maximum facilities of
100 watts and antenna height of 30 meters above average terrain would be very
small and occur only in the immediate vicinity of the LPFM station. For example,
even using NAB's median receiver performance test results for its three "worst"
FM radio categories, i.e., clock, personal and portable, we find that the area
where such receivers could potentially experience degradation from interference
is small, generally 1 km or less. This interference analysis is shown in the
following table:
LPFM Potential Interference Radius Based on NAB Tests
Receiver Desired Signal Level
Category -45 dBm -55 dBm -65 dBm
(Close to Station) (-Principle Community) (-Protected Service)
Clock 0.3
km (0.2 mi.) 0.7 km (0.4 mi.) 2.1 km (1.3 mi.) Portable 1.0 km (0.6 mi.) 0.9 km
(0.6 mi.) 1.0 km (0.6 mi.) Personal 0.4 km (0.3 mi.) 0.5 km (0.3 mi.) 0.5 km
(0.3 mi.)
The above Table shows the approximate radius around an LPFM
station where interference could potentially occur to a 3rd adjacent channel
full service station with different types of radios, based on the NAB test data.
As indicated in the Table, the area of potential interference depends on the
type of radio used and on whether the LPFM station is located relatively close
to the "desired" full power station, i.e., at the -45 dBm contour, or whether
the LPFM station is at the edge of the full power station's service area, i.e.,
at the -65 dBm contour. For example, if an LPFM station is located about 9 or 10
km from a 3rd adjacent channel Class A full power station (-45 dBm), a listener
using a clock radio located about 0.3 km (about 1000 feet) from that LPFM
station could experience some degradation in service. If the LPFM station is
located at the edge of service of the full power station, the radius of
potential interference would increase to about 2.1 km. Alternatively, if the
listener were using a personal or "Walkman" type radio at the edge of coverage
of the full power station, the potential interference area would have a radius
of about 0.5 km.
I should be noted, however, that the actual audio S/N
value that NAB uses to "define" where interference begins would be different for
these two cases. For clock radios, interference at the edge of coverage would be
said to begin to occur at a value of 41.5 dB S/N. This is a level we believe
that most listeners would find more than acceptable for clock radio use. In the
case of the personal radio, the value would be 20.3 dB, which may indicate, as
discussed above, that these radios are not providing satisfactory service out to
the protected contour of a full service station.
Further, we believe
that this analysis provides a conservative estimate of the actual interference
potential of LPFM. given NAB's performance criteria and the fact that NAB's
sample included some of the poorer performing radios among the four studies. In
addition, whether interference, in fact, occurs to FM listening depends on a
number of factors, besides the performance of the FM receiver. These include,
among other things. the actual reception conditions, such as the location and
position of the radio, the frequency and location of both the desired and
undesired stations, and the type of program material being transmitted and
received. CEA noted, for example, that when the desired signal was modulated
with rock music the interference was masked in its 2nd and 3rd adjacent channel
subjective tests.
Conclusion
Based on the record before us. we
therefore found that LPFM stations operating with 100 watts power or less on 3rd
adjacent channels would not result in significant new interference to the
service of existing FM stations. The Commission also concluded that any small
amount of interference that might occur would be outweighed by the benefits to
listeners from the new services to be provided by LPFM stations. With regard to
2nd adjacent channel protection requirements, we concluded that, since receiver
performance appears to be only at about the same level as that provided in the
rules, the risk of interference from LPFM signals on 2nd adjacent channels may
be somewhat higher. We therefore applied 2nd adjacent channel separation
requirements to these stations that are consistent with the -40 dB standard
reflected in the current FM rules.
In concluding, I want to express my
gratitude to the Subcommittee for the opportunity to appear before you today.
The Commission understands and shares the industry's concerns for protecting the
integrity of the FM band. Please be assured that we have made every effort to
consider all the available information in this matter. I believe the
Commission's LPFM decisions fairly address the concerns of all interests and
that this new service will not compromise existing FM service. I would be
pleased to answer any questions you may have.
FOOTNOTES:
1 See
FM Interference Tests, Laboratory Test Report. Thomas B. Keller, Robert W.
McCutheon, Consumer Electronics Manufacturers Association (CEMA). conducted
under the auspices of National Public Radio (NPR), CEMA and the Corporation of
Public Broadcasting (CPB); Technical Studies and Reports filed by the National
Association of Broadcasters; and. Receiver Evaluation Project conducted by
Broadcast Signal Lab, LLP for the National Lawyers' Guild. Committee on
Democratic Communications. CEMA has since become the Consumer Electronics
Association (CEA).
2 Signal-to-noise (S/N) is one of the ways to
characterize audio quality. It is the measure of the relative volume of the
desired sound to the noise that may be present in the system. Noise manifests
itself as "hissing" or static. A higher S/N ratio indicates better audio
quality. A lower S/N ratio means the output will sound noisier. S/N ratio is
measured in decibels or dB, a logarithmic expression of ratios. For example. 10
dB means that the signal is ten times stronger than the noise and 20 dB means
that the signal is 100 times greater than the noise. To meet the NAB 50 dB S/N
criterion, the volume of the desired sound would have to be 100.000 times
stronger than the volume of the noise. Since many of the radios tested by NAB
did not meet its 50 dB value, NAB also employed a degradation in S/N of 5 dB as
a measure when the desired service is impaired.
3 See NAB study
entitled, "Subjective Evaluation of Audio Degraded by Noise and Undesired FM
Signals" by Lawrence C. Middlekamp, November 17, 1982, cited in para. 97, p. 38,
of the FCC's Report and Order in MM Docket No. 99-25.
END
LOAD-DATE: February 19, 2000