Copyright 2000 Federal News Service, Inc.
Federal News Service
February 17, 2000, Thursday
SECTION: PREPARED TESTIMONY
LENGTH: 3346 words
HEADLINE:
PREPARED TESTIMONY OF DR. THEODORE S. RAPPAPORT, P. E.
BEFORE THE
HOUSE COMMERCE COMMITTEE TELECOMMUNICATIONS & FINANCE
SUBCOMMITTEE
SUBJECT - COMMERCE ON SPECTRUM INTEGRITY AND HR
3439, THE "RADIO BROADCASTING PRESERVATION ACT OF 1999".
BODY:
Thank you for the honor to appear
before you today. My name is Dr. Ted Rappaport. I am the James S. Tucker
professor of electrical engineering at Virginia Tech, Blacksburg, and have been
on the faculty for 12 years. In 1990, I founded Virginia Tech's Mobile and
Portable Radio Research Group, one of the world's first research and education
centers to specialize in the field of wireless communications. I also serve as
Chairman of Wireless Valley Communications, Inc. in Blacksburg, VA. My research
expertise is in the areas of radio wave propagation, communication system
design, signal processing, and emerging broadband wireless communications. I
have authored or coauthored more than 10 books in the field of wireless
communications, including the popular textbook "Wireless Communications"
published by Prentice-Hall. I received my engineering degrees from Purdue
University in the 1980's, and in 1992 was recipient of the National Science
Foundation (NSF) Presidential Faculty Fellowship. I am a registered professional
engineer in the Commonwealth of Virginia.
I became acquainted with
low power FM radio, also known as LPFM, when I was approached
last summer to perform technical analysis on behalf of a coalition of churches,
non-profit foundations, and other public- interest groups, led by the United
Church of Christ and their lawyers at Media Access Project. Before I agreed to
do any work for them with regard to LPFM, I insisted the public interest groups
would have to accept my results based on technical analysis, without bias or a
predetermined outcome. The groups seeking my technical analysis agreed to these
conditions, and I carefully studied the Notice for Proposed Rule Making (NPRM)
for LPFM. It seemed well thought out, and made a compelling case for LPFM
stations. In the NPRM, the FCC asked for technical analyses from the public to
help them in the rulemaking process.
After reading the NPRM for LPFM, I
agreed to provide a detailed technical analysis of LPFM through my engineering
company, Wireless Valley Communications, Inc. To determine the technical
feasibility of low power radio, my staff and I did two things. First, we
performed extensive analysis and computer simulation using the FCC's own
interference protection rules and licensing procedures for existing FM radio
stations. This analysis allowed us to determine how the addition of LPFM
stations would impact existing FM stations, as well as emerging digital radio
services. Second, we conducted a rigorous review of some of the technical data
and public comments that had already been submitted to the FCC in response to
the NPRM for LPFM.
My analysis concluded that LPFM will not cause
unacceptable levels of interference to existing FM broadcast stations or their
listeners. My computer simulations demonstrate that under the conservative
proposal adopted by the FCC, in the absolute worst case, if all new LPFM
stations used 100 Watts, then at most, 1.6 percent of listeners who could hear a
new LPFM station might be unable to receive a currently- existing broadcast
station. More importantly, the large majority of the affected listeners would
actually be able to receive all current stations, and other affected listeners
would be able to receive an incumbent station by simply moving their radios a
few feet or by rotating them on their nightstands.In addition, when I analyzed
the technical data filed as public comments, I found that most of the technical
studies would not meet the objective standards necessary for peer review or
publication acceptance in the engineering community. Standards for peer review
include the open disclosure of all formulas, assumptions, data processing
methodologies, and in some cases software codes, such that others who are
familiar with the technical issues can evaluate, replicate and corroborate
results. To best serve the interests of the FCC and the public, I firmly believe
that public comments of a technical nature should be filed such that they can be
peer reviewed and stand up to scrutiny and objectivity. The studies filed by
some opponents of LPFM, unfortunately, lacked technical details or objectivity,
and were based on the misguided premise that most FM radios today do not work
properly. This is clearly not true. Most consumers today are very pleased with
their FM radios as evidenced by the lack of public outcry or FCC complaints.
In the end, the FCC adopted a very safe and conservative ruling that is
certain to minimize LPFM interference to incumbent broadcasters and listeners.
The FCC was originally considering whether to create three sizes of radio
stations - 10 watts, 100 watts, and 1000 watts. In addition, the FCC was
considering whether to change the transmitter spacing protections around those
stations by lifting what is called third adjacent and second adjacent channel
protection levels. These transmitter spacing rules create cushions (interference
protection zones) around radio stations so their transmissions do not interfere
or"bleed" with one another. Existing commercial FM stations are required to obey
these spacing rules prior to licensure.
I determined that 1000 watt LPFM
stations required full protection - both second and third adjacent protection.
Ten watt and 100 watt stations are so small in power, however, that they cover
such a small area and therefore do not require either second or third adjacent
channel protection. The proposal the FCC adopted is more conservative than my
recommendations. The FCC not only decided not to adopt 1000 watt stations, but
they also retained second adjacent channel protection for the smaller 10 and 100
watt stations. This assures even greater interference protection to incumbent FM
broadcasters and current station listeners than I had recommended, since it
greatly reduces the number of possible LPFM stations that will be allowed. My
computer analysis considered a wide range of possible interference rules,
including the case of second adjacent channel protection which the FCC has
adopted (see Appendix D of "Technical Analysis of the Low Power
FM Service" by Wireless Valley Communications, Inc., August 26, 1999,
submitted to Media Access Project for public filing). My analysis found that, by
using worst case interference assumptions and by relaxing the second and third
adjacent channel protections, 626 new LPFM stations could be added in 60 US
cities. My recommendations would have allowed over 81 million new
citizen-channels on the FM airways, with a worst case potential interference of
1.2 million citizen- channels (however, since the analysis was worst case, only
a small fraction of the 1.2 million citizen-channels actually would have
experienced interference of some kind). However, the FCC adopted a more
conservative approach, and insisted that all LPFM stations must obey the
existing second adjacent channel projection rule, which reduces the number of
new LPFM stations to 247 in the same 60 US markets. This reduces the number of
citizens-channels by almost 300%, and decreases the number of potential
interference events by the same factor.Details Behind My Computer Analysis
Let me now provide further details about the computer analysis that
demonstrated low power radio would not harm current broadcasts. My computer
analysis included an extensive radio spectrum simulation to demonstrate that
hundreds of LPFM stations may indeed be deployed in the top U.S. markets with
minimal impact to incumbent and future digital FM radio stations. We used the
FCC's FM radio license database, the FCC radio propagation programs, and Part 73
interference and coverage rules for FM radio stations, to show that properly
certified LPFM transmitters with radiated power levels between 1 and 100 Watts
and no 2nd or 3rd adjacent channel protection requirements can serve tens of
millions of neighborhood listeners in the U.S., while having minimal
interference impact on a very small fraction of listeners. My computer program
increased the granularity, or precision, of the FCC's models.
In
addition, my computer program analyzed the impact of 10 watt and 1 watt
stations, which the FCC did not do in its original NPP, M, and considered other
channel protection schemes.
We spent several weeks analyzing the FCC
radio propagation programs and improving the FCC's software that is used for
issuing standard FM radio licenses. In addition to analyzing new LPFM stations
having power levels of 1000, 100, 10 and 1 watt, we also developed programs that
could draw maps of the possible locations and the maximum number of LPFM
stations that could be supported within a specific market for a given protection
ratio ruling. To verify that we were following FCC FM radio license guidelines
and to make certain that our programs were working properly, we spoke with FCC
engineers throughout the process to verify our programs recreated the same data
which FCC engineers could obtain with their original program. Since the FM radio
license database is constantly changing, we used the most recent version of the
FM station license database. The FCC's FM radio station license database
includes key technical details that are vital for determining whether or not any
new FM stations might cause interference.
These key details include
radio frequency, geographical position, and transmitter power of each FM station
license in the US, as well as similar data for FM stations licensed near the US
borders in Canada and Mexico. Using our modified programs, and considering a
wide variety of transmitter powers, interference protection rules, and
geographic resolutions, we determined the exact number of viable LPFM stations
in 60 representative US cities, and presented maps which illustrate possible
LPFM locations in many of these markets. Once written, our computer program took
about 2 days of continuous computer time on a 400 MHz personal computer to
produce the results provided in our public comments submitted to the FCC.
I wish to point out that we have provided both the source code and
executable code of our computer programs with our filing, and believe they could
be of significant value to the FCC and to the public. In fact, these programs
could be used with very little modification by the FCC or a private entity to
properly license LPFM stations in the US. All of this data is available to the
public on the Media Access Project web site at http://www.mediaaccess.org/.
Our analysis shows that between 64 and 680 times as many citizens are
able to receive LPFM programming over small distances (i.e. within
neighborhoods) as compared with those who may rarely experience some level of
interference or degraded service. Even those listeners experiencing some
degradation of service will likely be able to improve their reception by simply
relocating their radio or adjusting their antenna.1
In my presentation
to the FCC, I included maps to demonstrate suitable locations of LPFM stations
in several representative cities. These maps demonstrate the careful analysis
and limited nature of the new low power radio stations. They show that not every
city will accommodate low power stations. In addition, in certain cities, it
will be possible to add new stations in only certain areas of a city. Thus,
concerns that low power stations might pop up like mushrooms, or like the holes
in Swiss cheese, without regard for current broadcasts is completely false.
Careful, stringent engineering analysis shows where the stations may safely be
added and this same analysis must be used for the proper issuance of low power
radio licenses.
Although we made all of our information publicly
available, the opponents of low power radio have been unable to find any flaws
in my analysis.
Details Behind My Analysis of Other Studies
The
receiver studies submitted to the FCC by low power radio
opponents show that the true "real world" FM interference
environment for household radios is benign, due to the FCC's unnecessarily high
interference protection ratios which stem from the state-of-the-art several
decades ago. The receiver studies offer very strong support for LPFM as a viable
service without the need for 2nd and 3rd adjacent protection ratios, because
today's fixed and portable FM radios operate successfully with much less
interference protection than assumed by the FCC in its present station licensing
process. The small additional interference introduced by LPFM is miniscule in
comparison to already existing levels of interference in the FM band.
A
simple analogy will explain the basis and conclusions of the NAB's and CEMA's
studies. Let's imagine there is a Federal Building Commission (FBC) that
regulates the occupancy of people on floors in office buildings. Let's say that
the Commission's rules require each building owner to assume that each person
weighs, on average, 300 pounds, and that each person occupies a particular floor
area, say 6 square feet. The building owners, analogous to FM station license
holders, are thus required to limit the number of people they allow to live on
each floor of their building according to FBC rules.
However, the
construction companies, analogous to radio manufacturers in this example,
realize that they can safely build buildings at much less cost ifthey assume
that, on average, every person only weighs 200 pounds. Just as the radio
manufacturers for FM radio are not regulated by the FCC to provide specific
technical specifications of their product, the construction companies are not
regulated by the Federal Building Commission, so a wide range of construction
techniques and building materials are used.
Assume this is what is done
for years, with great success. Now, assume time passes and some new building
owners wish to build small, low-cost buildings, but wish to allow more people to
live on each floor of their buildings, because they have fewer resources and
wish to provide shelter to more patrons. The Federal Building Commission decides
that it has been too restrictive, and proposes that the safety standard for
occupancy of floors in office buildings should be relaxed a bit to assume
everyone weighs 250 pounds instead of 300 pounds -- since this will allow the
new building owners to allow more people within a building floor.
But
the construction companies and building owners now claim that the Federal
Building Commission is going too far -- they cry "Wait, the current buildings
don't even meet the safety standards now, how can we relax them further?" But
the construction companies and building owners already know that the original
rules were far, far too restrictive. In fact, the construction companies have
actually been assuming people weigh less on average all along, and in fact have
been building offices for years which serve the public well using less costly
materials. It is clear from this example that the Federal Building Commission's
relaxation of the rules will have no impact on the existing buildings or
theconstruction companies. Buildings will continue to hold occupants. All that
has happened is the Federal Building Commission has realized that the old rules
were much too restrictive and unrealistic, and has successfully accommodated the
request of a handful of new, smaller building owners.
This is the same
situation for FM radio. Radio manufacturers and FM station license holders have
known that the FCC rules for FM broadcast licensing provide an overabundance of
interference protection. By FCC licensing guidelines, FM radio stations are
spaced far apart in such a conservative manner as to prevent radio interference.
This in turn allows FM radios to be manufactured very inexpensively. The FCC
rules for FM broadcast licenses offer so much spacing (e.g. interference
protection) because they were developed when FM radio was in its infancy, when
older FM radio receivers were far more susceptible to adjacent channel
interference and frequency drift than today's receivers. In fact, the FM station
license rules used today were developed before most FM receivers used completely
integrated receiver circuits (chips). Today's modern integrated circuit design
and filtering technologies are far more robust to drift and interference than
radio receivers of 30 years ago. The technological advances in receiver
technology (just look at today's cellphone -- its much more robust than its
shoebox counterpart of 1985) is why the addition of a few LPFM stations in each
market will make virtually no difference to the listening public.
It is
important to note that the FCC rules for FM broadcast licensing have no
regulatory bearing on how FM radio receivers should perform or be constructed.
This is a wise and sensible approach that the FCC has traditionallytaken,
because it allows various manufacturers of radios to freely compete and
differentiate themselves on the basis of price and performance. In short, there
is a great deal of protection in the FCC's FM broadcast licensing standards.
Small stations of 10 and 100 watts will not harm any current broadcasts.
Opponents of LPFM did not objectively point this out or properly address the
relationship between FCC FM licensing guidelines versus commercial FM receiver
performance.
Another example will demonstrate the flaws in the NAB's
study. The NAB sought to identify how well FM receivers work by establishing a
performance standard. But more than half of the FM receivers tested in the NAB
study could not even meet the NAB's performance standards before the simulation
of new low power radio stations. That is, even in a perfect, interference-free
environment in the test laboratory, without the introduction of any additional
FM interference, NAB's experiments had more than 50% of the radios it tested as
failing its own performance standard in a noise-free environment! But we all
know that if we purchase FM radios at random, virtually all of them will work
fine. Put another way, according to the NAB, half of all radios they tested do
not perform acceptably today, even before LPFM is introduced! This result
obviously defies common sense. There were many other issues which, as an
engineer and reviewer, disturbed me and which would certainly disturb others if
they were looking for objectivity.
My hope is that this testimony has
helped you understand some of the technical issues involved with FM radio
licensing, FM receiver design, and theLow Power FM Process. I also hope it helps
clarify the work that my staff and I have conducted and made available to the
FCC and the public, for possible use in properly licensing LPFM stations in this
country. As an engineering professional who makes a living by teaching,
studying, and creating new technologies in the wireless communications field, I
am confident that the FCC's low power FM system, as recently
adopted, will have no detrimental impact on existing and future commercial FM
radio stations or their listeners, and will benefit millions of Americans with a
will and desire to communicate responsibly within their own neighborhoods and
communities. Thank you again for the honor to address you, and to serve our
nation in this matter.
FOOTNOTES:
1 People listening inside the
interference area would experience interference to an incumbent station's signal
if and only if all of the following conditions applied concurrently:
-
If the LPFM station were placed near the coverage fringe of the incumbent
station,
- If the incumbent station transmits on a channel 2 or 3
channels above or below the LPFM station's assigned frequency,
- If the
listener only wishes to listen to the incumbent station out of the dozens of
stations available, and - If their radio happens to be a poor-performing model
like a clock radio. In many instances, the listener would be able to "tune" out
the LPFM interference by moving the FM receiver. It is quite common for people
to adjust the position of their clock radio or boom box for good reception. Such
adjustment could cause the LPFM interferer to fade while maximizing the desired
signal.
END
LOAD-DATE: February 19,
2000 
