Subject: [NEXTEL-1] FCC On- Interference Immunity Performance Specifications for Radio Receivers

From: Marcel <[email-masked]>
Date: Mon, 24 Mar 2003 16:36:08 -0500

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

In the matter of

Interference Immunity Performance Specifications for Radio Receivers

Review of the Commission’s Rules and Policies Affecting the Conversion to Digital
Television

http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-03-54A6.doc

ET Docket No. 03-65

MM Docket No. 00-39
NOTICE OF INQUIRY

Adopted:  March 13, 2003        Released:  March 24, 2003

Comment Date:  [75 days from publication in the Federal Register]
Reply Comment Date:  [105 days from publication in the Federal Register]

By the Commission:  Chairman Powell, Commissioners Abernathy, Copps, Martin and Adelstein
issuing separate statements.

I. INTRODUCTION
1. By this action, the Commission begins consideration of incorporating receiver
interference immunity performance specifications into our spectrum policy on a broader
basis.  Such specifications could be in the form of incentives, guidelines or regulatory
requirements (or a combination of these) in particular frequency bands, services or across
bands and services.  We believe that incorporation of receiver performance specifications
could serve to promote more efficient utilization of the spectrum and create opportunities
for new and additional use of radio communications by the American public. From a
technical standpoint, a radio receiver’s susceptibility to interference is largely
dependent on the interference immunity of the device, particularly with regard to its
rejection of undesired radiofrequency (RF) energy and signals.  If the receivers used in
connection with a radio service are designed to provide a certain immunity or tolerance of
undesired RF energy and signals, more efficient and predictable use of the spectrum
resource can be achieved.  Such receiver improvements could also provide greater
opportunities for access to the spectrum.  These opportunities will potentially lead to
consumer benefits in the form of innovation, competition and choice among services and
devices.

2. Increasingly in recent years, the preemptive effect of minimally performing receivers
has been demonstrated, as licensees seek protection for service predicated on the
performance of receivers with little tolerance for other signals.  Had the RF environment
in which these services would be expected to operate in the future, or the expected
performance characteristics of those receivers, been defined in some way, these services
could have been developed with receivers that could better tolerate the introduction of
newer services on the same or proximate frequencies.  Accordingly, in this Inquiry we seek
information, comment, and research on issues concerning the current receiver environment,
i.e., the immunity performance and interference tolerance of existing receivers, the
possibilities for improving the level of receiver immunity in the various radio services,
and the potential positive and negative impacts of receiver standards on innovation and
the marketplace.  We also request comment on the possible approaches by which desired
levels of receiver immunity or tolerances could be achieved, including incentives for
improving performance, voluntary industry standards, mandatory standards, or a combination
of these or other approaches.  In this regard, it is not our intent at this time to
implement a new regulatory regime that would generally subject all receivers to mandatory
standards.  Rather, we believe it is preferable to rely primarily on market incentives and
voluntary industry programs that provide for flexibility in establishing and managing
guidelines for receiver immunity, rather than formal mandatory standards incorporated into
our rules.  At the same time, we note that in the past the Commission has mandated various
transmitter standards in order to control interference levels.  As we recognize that
receivers can contribute as much as transmitters to the existence of perceived
interference, there may be benefits to the adoption of guidelines, labeling rules, or even
mandatory standards for certain classes of receivers.  This may be particularly relevant
in situations where we continue to find that command and control spectrum management
techniques are in the public interest [e.g., public safety] or in situations in which it
is not possible for all the relevant industry and consumer parties to reach voluntary
agreements.
3. We further request information and comment on the considerations that should guide the
Commission’s approach to these matters in the various licensed radio services.  This
proceeding builds upon recent work of the Spectrum Policy Task Force (Task Force) to
examine means for improving the management of the radio spectrum to increase the public
benefits derived from use of the spectrum resource.   In its Report, the Task Force
concluded that the increases in demand for radio services in the limited amount of
available spectrum and the rapid advances in radio system technologies, including new
digital transmission systems, in recent years are necessitating that the Commission change
its traditional model for managing the radio spectrum.  The Task Force observed that
greater opportunities for spectrum access would be facilitated if the minimum performance
characteristics of the receiver were known and therefore recommended that we make receiver
performance a more prominent part of our spectrum policy.   In response to the Task Force
report, a number of parties expressed their support for receiver standards and guidelines
developed by industry standards groups.   Several parties expressed support for Commission
mandated requirements for certain receivers.   Other parties oppose mandated receiver
standards and guidelines.

II. DISCUSSION
4. The principal limiting factor in the allocation and assignment of radio frequencies is
interference to received signals.  Radio interference can occur when RF energy other than
a desired signal is present in a receiver.  Such undesired energy can be present from the
emissions of one or a combination of other sources generating RF energy  or can be
generated within the receiver itself.  Interference occurs when undesired RF energy is
manifested in a radio communication system as a performance degradation,
misinterpretation, or loss of information that could be extracted from a desired signal in
the absence of the unwanted energy.   The adverse effects of undesired energy present in a
receiver can be minimized by improved design of the receiver.

5. The Commission’s radio spectrum policies and rules, including its efforts to promote
spectrum efficiency, traditionally have relied primarily on approaches that control the
emissions and locations of transmitters and the frequencies used by specific types of
radio operations.  Under this model, the Commission has established operational parameters
in given portions of the spectrum in which the pattern of radio signals, both
geographically and technically, is well understood and generally predictable by equipment
manufacturers and licensees.  Manufacturers could design and market products for
designated services within these parameters and the predicted environment.  In some
services, licensees could choose the transmitter and receiver products that best meet
their particular needs for the provision of radio communication services.  In other
services, including broadcast radio and television services, receiver products are
designed and marketed for a mass consumer market, with the licensees having limited
control or influence over their technical parameters and capabilities. Therefore, to some
extent our existing rules, such as the TV allotment table, while limited to transmitting
requirements, also assume certain levels of receiver performance.

6. Generally, this model has served well to control interference and to facilitate
effective use of the spectrum in environments in which the specific services and operating
technology are stable and very well defined.  However, as recognized in the Task Force
Report, the dramatic increases in the overall demand for spectrum based services, rapid
technical advances in radio systems, in particular the introduction of various advanced
digital modulation technologies such as code division multiple access (CDMA), and the need
for increased access to the limited supply of spectrum in recent years are straining the
effectiveness of the Commission’s longstanding spectrum policies.   These changes are
prompting the Commission to revisit its traditional model and evolve its spectrum policy
toward more flexible and market-oriented approaches that will provide incentives for users
to migrate to more technologically innovative and economically efficient uses of the
spectrum.

7. We now need to provide opportunities for an ever increasing array of new digital radio
technologies and services and to allow licensees the flexibility to implement and modify
these new technologies and services in accordance with market forces.  We also need to
relieve equipment manufacturers and service providers from the delays inherent in our
regulatory processes, in particular, those involving lengthy rule makings.  To meet these
needs, we have implemented new licensing schemes under which bands of spectrum are
assigned to licensees on a geographic basis and those licensees are allowed the
flexibility to determine the nature of the services that operate in that spectrum and the
technologies used to provide those services.  The only operating restrictions applied to
these operations are those necessary to ensure that interference is not caused to services
operating in adjacent geographic areas or on adjacent frequency bands.  These restrictions
typically take the form of limits on signal strength at the edge of a licensee’s service
area and limits on maximum transmitter power, antenna height and out-of-band emissions.

8. As a result of the above changes, it often is not possible to perform a reliable,
comprehensive analysis to predict the strength of potential signal sources in a given
frequency band and geographic area because licensees have discretion to select and modify
transmitter locations, operating power, antenna directivity and type of transmissions.  In
addition, we observe that new digital technologies generally are inherently more robust,
and resistant to interference, than analog systems.   Our spectrum policies should account
for this increased ability of digital signals to tolerate the presence of other signals.
Further, with the increasingly intense use of the spectrum, there are now very few
opportunities to allocate unused spectrum for new services and correspondingly, few bands
in which there are not many users seeking to access the available frequencies.  Thus, as
indicated in the Task Force Report, interference management is now more difficult because
of the greater density, mobility, and variability of transmitters and our flexible use
policy that  allows users the flexibility to determine how and where to operate in their
assigned spectrum.

9. As part of our effort to revise our spectrum management policies to address the changes
in RF operations and environments that have occurred in recent years, we are now beginning
to investigate alternative approaches for managing interference.  Consistent with the
recommendations of the Task Force, we believe it will be necessary to shift our current
paradigm for assessing interference from approaches based primarily on transmitter
operations towards new approaches that focus on the actual RF environment and interaction
between transmitters and receivers, such as the interference temperature metric.   Such
new approaches would better allow the Commission to anticipate and enable future users of
the spectrum while providing a greater degree of certainty to incumbents regarding the RF
environment they will continue to operate in.

10. In many cases, the effects of RF interference can be mitigated or eliminated through
attention to receiver hardware design and signal processing software.  There are many
attributes of receiver performance that can be varied to increase a device’s immunity to
undesired emissions, and standards could be established for minimum performance
requirements.  Improving the general level of receiver performance with respect to
interference immunity would allow increased operation of radio services on adjacent
channels and frequency bands and thereby promote spectrum sharing and radio system
interoperability that would permit more efficient use of the spectrum.  In addition, more
robust receiver performance would help to facilitate more flexible use of the spectrum.
Such robust performance would allow receivers to tolerate changes in operating systems,
services and frequency loading that are expected to occur under flexible use of the
spectrum.  At the same time, however, we recognize that improvements in receiver
performance almost always increase production costs, and so there are trade-offs in costs
and performance that must be balanced.  In addition, we need to address how the benefits
of upgraded receiver performance would be distributed among users.  For example, improved
receiver immunity may permit government operations over wider areas or at higher powers
without causing interference.

11. In this proceeding, we seek additional information on the broad range of issues
relating to the possible incorporation of receiver performance incentives, guidelines or
standards.  As discussed below, we invite interested parties to submit information,
research, and comment on subjects including:  potential receiver performance parameters,
the manner in which receiver immunity performance capabilities should be incorporated into
our spectrum policies and rules, including the scope of our authority to establish
mandatory receiver standards by rule ; possibilities for use of receiver interference
immunity performance guidelines and standards in specific radio services; the impact of
receiver minimum immunity performance requirements on innovation and the marketplace; the
current receiver environment; and transition issues such as the treatment of legacy
receivers.
A. Receiver Performance Parameters

12. A radio receiver’s immunity to interference is dependent on a number of factors in its
technical design and, in addition, the characteristics of the signals it receives.  These
factors may be closely related and in many cases interdependent, and a receiver’s
performance in one factor may often affect its performance in others.  The factors
determining receiver immunity performance generally include selectivity, sensitivity,
dynamic range, automatic RF gain control, shielding, modulation method, and signal
processing,.  Receiver selectivity is the ability to isolate and acquire the desired
signal from all of the undesired signals that may be present on other channels.
Selectivity is a central factor in the control of adjacent channel interference.
Sensitivity is the measure of a receiver’s ability to receive signals of low strength.
More sensitivity means a receiver can pick up lower level signals.   Dynamic range is the
range of the highest and lowest received signal strength levels over which the receiver
can satisfactorily operate.  The upper side of a receiver’s dynamic range determines how
strong a received signal can be before failure due to overloading occurs.  Automatic RF
gain control allows a receiver to adjust the level of a received signal as it appears at
the unit’s signal processing and demodulation sections.  It can also be used to improve a
unit’s dynamic range and provide protection against overload.  Shielding can consist of
metal boxes, foil or other materials that isolate sections of a receiver from undesired RF
energy.

13. Signal processing provides increased ability to isolate a desired signal from other RF
energy, including another (undesired) transmitted signal.  The degree to which
interference immunity can be achieved through signal processing depends on the modulation
method used for the transmitted signal.  For example, the CDMA digital modulation system
allows multiple signals to be transmitted and received simultaneously on the same
frequency in the same area without intra-system interference.   The analog FM modulation
system provides for a “capture effect” from processing gain that allows a receiver to
demodulate only the strongest signal present.  Finally, in digital systems, trade-offs can
be made between signal strength and data rates.  In order to receive signals with higher
data rates, it is generally necessary to have higher levels of signal-to-interference
ratio (S/I ratio).   Thus, in the presence of interfering signals the data rate could be
adjusted to provide satisfactory reception.  The interference immunity provided by signal
processing and modulation systems is due to radio system design and signal architecture,
rather than specific receiver attributes such as filtering.  However, because proper use
of these system factors can provide improvements in interference immunity, we are
including them in the subjects to be investigated in this proceeding for inclusion in our
spectrum policies.

14. We request comment and information on the factors or combination of factors and their
interaction that we need to consider in developing receiver interference immunity
performance guidelines and standards, as well as the costs and benefits of such guidelines
and standards.  We specifically request comment on the factors affecting interference
immunity we have identified above and their relative importance.  We also invite parties
to identify additional factors that we should consider in establishing and applying
receiver immunity standards.  We also seek comment and information in response to the
following questions:
- Are there any special hardware designs, software methodologies, or new technologies
available that would significantly enhance receiver immunity performance?
- How are these performance factors related to frequency and operating power, and
influenced by the nature of the RF environment?
- To what extent, and in what way, are some factors affecting interference immunity
relatively more important than others across receivers used with different services or
across devices that receive signals transmitted using different modulation methods?
- Are there factors that must be considered as a group and not independently due to their
cross-interactions or relationships with other factors?
- Are some factors less important in providing interference immunity in certain modulation
systems or receiver designs?
- How should any such differences be treated in specifying receiver immunity guidelines or
standards?
- Can receiver interference immunity parameters be ranked in accordance with their level
of importance to performance?  What procedures or criteria should be used to determine how
to trade off the level of receiver performance with the practical issues of cost and
implementation?
- Should system characteristics such as signal processing gain and modulation methods that
facilitate immunity from interference in receivers be considered germane to the process of
establishing receiver performance guidelines or standards?
- Do new and emerging advanced radio systems, including those employing digital
modulation, offer potential for significantly improving receiver immunity to interfering
signals? What are the inherent performance limitations of these technologies?

15. As mentioned above, the interference environment in which a receiver operates can be
highly variable and its characteristics may often be strongly service related.  That
environment must first be identified and characterized to allow, at least in principle,
the development of emission criteria that provide for quantitative comparisons of receiver
performance.   We request comment on the following questions concerning the interference
environment in which receivers operate:
- What are the characteristics of the RF environment in which existing receivers or groups
of receivers operate?
- If studies were to be carried out, what would be an efficient way to capture any
relevant data or pertinent events given the dynamic changing nature of the environment
over time?
- Should different receiver specifications or approaches be taken based on the environment
in which the receiver is expected to operate (for example, high-powered or lower-powered
frequency bands).

16. Another approach to describing the interference environment would be to develop a
generic environment in which all receivers would be expected to perform adequately.  Once
the environment was identified, criteria directly related to receiver performance in that
environment could be established.  One way to measure performance would be to look at the
signal to noise levels (S/N) of analog systems and the bit error rate (BER) of digital
systems.  These metrics are quantifiable, but specific levels or ranges would have to be
developed.  Another approach to receiver performance quantification would be to use
generally agreeable criteria that have come about over years of development and
interaction with equipment and the marketplace.  For example, the 55 dB attenuation
standard for adjacent channel protection by cable compatible consumer electronics
equipment in Section 15.118(c)(1) was set based on manufacturers’ experience with such
equipment and their knowledge of the tolerance of equipment suppliers for that level of
performance.   We request responses to the following questions relating to the
establishment of a generic receiver environment and possibilities for measuring receiver
performance there under:
- If a generic environment were employed, how many conditions would have to be considered
to cover the variability of the natural environments, (i.e., narrow band, wide band,
closest frequency separation for interferer and carrier, etc.)?
- What measures of performance translate into good, acceptable, or poor operational
metrics?
- Could manufacturers agree on performance categories and could quantifiable ranges be
established for these categories?  How many categories would be needed and where should
the threshold for acceptable performance be set among those categories?

17. Digital technologies, in particular, provide flexibility for controlling almost all
aspects of transceiver performance.   Many receiver parameters can be software controlled,
perhaps in response to specific interference in the signal environment.  One example is
frequency agile transceivers with automated transmitter power and frequency control.  The
design of the systems that these transceivers are used with provides for control of the
frequency and signal strength used for operation.  Advanced antenna technology coupled
with system design techniques such as diversity, in terms of space, angle, frequency and
time could also be used to enhance reception.  We seek comments on whether and how system
design elements that would enhance radio receiver performance should be incorporated into
our receiver guidelines/standards program.  In particular we seek comment on the elements
of system design that should be included in receiver guidelines/standards and how we could
limit the impact of receiver guidelines/standards on system design flexibility.
B. Incorporation of Receiver Interference Immunity Performance Guidelines and Standards
into Spectrum Policy

18. We seek information and comment on how best to incorporate receiver interference
immunity performance specification into our paradigm for management of the radio
spectrum.  Initially, we envision that there could be three principal approaches for
implementing measures for improving receiver performance:  voluntary industry standards;
guidelines promulgated by the Commission, either in technical publications or as
advisories in the rules; and mandatory standards adopted into the rules.  As a general
matter, we would prefer to rely primarily on voluntary programs that are supported and
managed by industry, in conjunction with user groups as appropriate, to establish and
maintain guidelines and standards for receiver immunity performance, rather than formally
incorporate them into our regulatory programs.   We believe that this approach provides
the greatest flexibility for those developing and producing products to modify and update
technical guidelines and standards in response to changes in technology, consumer desires,
and economic conditions. We also believe that spectrum users have an incentive to reach
voluntary agreements that provide for additional spectrum use.  For example, the PCS
industry has developed more rigorous standards than the Commission has imposed.  On the
other hand, we recognize that under a voluntary approach, if owners of non-conforming
receivers experience interference, this might produce an incumbency problem that may limit
efficient use of the spectrum.  We seek comment on these issues.

19. At the same time, we will need to maintain a cooperative relationship with those
managing voluntary standards to ensure that they provide the performance levels necessary
to support more efficient use of the radio spectrum.  There may also be instances where
for various reasons it might be necessary or desirable for the Commission to exercise a
greater role in the development and management of guidelines or standards.  In such cases
we would prefer an approach by which the Commission would maintain the specified
guidelines or standards in either an FCC technical publication, such as the “OET Bulletin”
series or an advisory in the rules.  Finally, there may be some cases where it will be
necessary to incorporate the specifications of the standard into our rules.  We request
comment on the following questions with regard to the manner in which to incorporate
receiver guidelines and standards into our rules:
- What approaches should the Commission use for implementing receiver immunity performance
into its spectrum policies?  Commenting parties are specifically invited to submit
additional measures to augment the three approaches suggested above or to suggest
completely different plans.
- What benchmarks should the Commission use in determining the approach it should use in
implementing specific receiver interference immunity performance guidelines or standards
into its spectrum policies?
- With what organizations should the Commission work with to develop receiver performance
requirements?
- How should standards or guidelines be implemented for services in which licensees have
control over the receivers that are used, such as the cellular and PCS services, and in
which they do not have control over the receivers, such as broadcast services?

- What are the cost implications of the various options for approaches for incorporating
receiver interference immunity into our spectrum policies in terms of both cost of
equipment and flexibility for users/system designers?

- We also seek comment on how to enforce any receiver standards.

20. We also request comment on the criteria that should be used in determining how to
specify the form of immunity guidelines or standards.  Guidelines/standards can be in the
form of performance criteria that apply to the functional capabilities of a device or of
design specifications for the manufacture of portions of a device.  In general, we believe
it is desirable to continue the Commission’s traditional preference to specify
guidelines/standards as performance criteria, and to make such guidelines/standards
voluntary rather than mandatory.  This approach gives manufacturers freedom to design the
internal configurations of their products to compete on both price and functionality.
However, there may be instances where it would be more appropriate to specify
guidelines/standards for the design of some or all of the features of a device that affect
interference immunity.  We request comment on the forms in which we should specify
receiver interference immunity performance guidelines/standards and invite commenting
parties to submit suggestions for alternative forms of specifying receiver interference
immunity performance guidelines/standards.  We also request comment on the circumstances
under which any given form should be employed.  Finally, we ask how should the public be
informed of the interference immunity performance of receivers and the relevant guidelines
for specific types of radio operation, i.e., how would consumers know about receiver
performance in order to make informed decisions?

21. We also seek comment on the relationship between the appropriateness of receiver
standards and models used to manage the spectrum.   Limiting transmitter in-band power and
spill-over into adjacent bands and areas, together with the definition of assigned
frequency bands and areas, provide substantial definition to the interference environment
in which licensees must design their systems.  Given these rules, would the costs and
benefits of improved receiver interference performance be internal to licensees, and would
they thus make efficient decisions regarding receiver performance?  Would there be a need
for receiver standards under a fully implemented property rights model, where markets
allocate exhaustively and exclusively defined spectrum usage rights?  How would such rules
affect licensees, such as broadcasters, who do not have a decisional role in the
performance of consumer receivers?

22. We believe that the Commission has the necessary statutory authority to promulgate
receiver immunity guidelines and standards under Sections 4(i), 301, 302(a), 303(e), (f),
and (r) of the Communications Act of 1934, as amended.   We request comment on this
assessment of our authority.

C. Use of Receiver Interference Immunity Performance Guidelines and Standards in Specific
Radio Services

23. The receiver interference environment and demands placed on receiver performance are,
to a large degree, dependent on the specific service supported by the equipment and the
services provided on neighboring frequency bands.  For example, mobile services that
operate on relatively narrow channels with no guard bands or separation between
communications channels need to use relatively high quality receivers that are sensitive
to low level signals, provide good selectivity, and are resistant to overloading.
Similarly, a service which involves safety of life generally needs to use equipment that
is more robust in tolerating potentially interfering signals, to provide added assurances
of dependable, reliable operation in environments where such signals are present.  On the
other hand, the signals of the terrestrial broadcast services, such as AM radio, can be
received with relatively low cost receivers that may be less sensitive to low level
signals, less selective, and more susceptible to overloading.  As a result of such
differences, we intend to explore operational environments and characteristics of the
different types of services as they affect minimum receiver performance needs, as part of
our investigation in this proceeding.  As observed by the Task Force, the types of
operations and services occupying neighboring frequency bands are a significant factor in
the environment in which a receiver operates, and so we seek information on receiver
performance issues of specific types of service and operations relating to both the
in-band and out-of-band environments.

24. Given the large number of communication services, it appears more tractable to
consider grouping the service related receivers immunity performance parameters that would
most directly impact the development of receiver metrics.  One grouping by service would
include:  1) public safety services, 2) satellite services, 3) mobile services, d) fixed
terrestrial services, and 5) broadcast services.  Another grouping by area of use could
consider services functioning in metropolitan and rural areas.  Neither grouping is meant
to be exclusive, but simply to isolate major performance and environment factors that
could be considered for the development of receiver interference immunity performance
standards.  We seek comment on the types of groupings of services that would simplify the
development of robust receiver performance, recognizing that, whenever appropriate, we
have granted broad flexibility for licensees to offer different services in the same
frequency band in order to respond to ever-changing marketplace needs.  With the large
number of communications services that are currently in operation, a program to study and
define minimum receiver performance specifications across all radio services will be a
substantial undertaking.  We request comment and suggestions on how to plan for and manage
such a program should we decide to undertake it.  In particular, we request comment and
suggestions regarding the services and/or receiver types with which to begin and how we
should organize the process for defining immunity specification.  We intend to closely
involve industry and other interested parties that have expertise and interest in these
matters in the specification process and request comment on how that involvement should be
arranged.  In this same context, we request comment on the parties that should be included
in the work on developing standards for receivers use in the various services and/or
service groupings.  As discussed above, the specification of minimum receiver interference
immunity performance guidelines/standards will involve tradeoffs in costs and perhaps
other factors.  We therefore ask for information on the cost implications of the various
options for minimum immunity specifications for receivers used with the various radio
services.  We seek comment on issues relating to receiver immunity performance and
guidelines/standards in our suggested service groupings as discussed below.  We also seek
comment on whether these groupings are appropriate, or whether grouping by other factors
such as frequency band or operating bandwidth are more appropriate.

25. Public safety services – Public safety communications systems are used by
organizations such as police, fire and emergency medical services whose mission often
involves safety of life.  These organizations need and, indeed, demand that their
communications systems provide a very high degree of reliability.  Thus, the operating
requirements of public safety communications systems would seem to warrant or even
necessitate the use of receiver immunity performance guidelines/standards that are tighter
than those for general communication services.  This could be affected perhaps by
requiring that the guidelines/standards for public safety receivers be set higher than
those for other equipment.  We ask the following questions in this regard:
- Should we adopt an approach that would subject public safety communications systems to
higher requirements for receiver interference immunity performance than other classes of
receivers?
- What parameters of public safety system performance should be subject to minimum
guidelines/standards for immunity to interference and how should we establish such
guidelines/standards?
- What values should be specified for the parameters of public safety receiver
interference performance?
- Are the reliability needs of public safety systems used for different types of
operation, such as dispatch, personal location/identification, video/audio monitoring,
telemetry, etc. different and if so, how should these differences be treated in
establishing minimum performance guideline/standards?
- In cases where a general communication service can be used in a safety of life or
property mode (such as E911 and VHF marine), should receivers used with such services be
subject to guidelines/standards for interference immunity similar to those for public
safety of receivers when operating in a safety mode?

26. As an illustration of a current approach on receiver standards for public safety
services, the Public Safety National Coordination Committee (hereinafter the “NCC”) has
identified technical standards for radio receivers operating on the interoperability
channels in the 700 MHz public safety band.   It has also proposed that these standards be
incorporated into the equipment certification requirements of Part 90, Subpart R of our
rules, 47 C.F.R. 90, Subpart R.   In developing these proposals, the NCC considered
recommending a metropolitan statistical area interference environment and a less stringent
rural service area interference environment.   However, it concluded that all of the
receivers operating on the interoperability channels of the newly allocated 700 MHz public
safety band should meet the metropolitan environment standard partly because of their
public safety nature, and partly because of the inherent difficulty of enforcing a rule
that specifies that certain radios can be used only in certain geographic areas.  The NCC
also decided not to specify receiver standards for radios operating on the
non-interoperability channels in the 700 MHz public safety band since the technologies to
be used in that portion of the band are not fully known.  It deferred to the marketplace
on that issue.  We request comment on the possible use of similar approaches, including
the reliance on a national committee process for development of receiver immunity
standards for other public safety bands.

27. Satellite services – Satellite receivers must be very sensitive to low level received
signals and therefore can be adversely affected by communications systems in adjacent
bands.  They can also experience interference from low level ambient noise sources that
are below the minimum sensitivity level of receivers used in other types of radio
services.  Satellite communications systems are currently used for radionavigation, mobile
communications, broadcast video and audio services, and fixed services.  Each of these
types of service has its own operating considerations and some are much more robust with
respect to interfering signals than others.  For example, fixed satellite systems that
operate with geo-stationary orbit (GSO) satellites may use high gain antennas that provide
high levels of signal, thus mitigating the relatively low level of the received signal.
Fixed receivers used with direct broadcast satellite services also use dish antennas that
provide considerable gain.  However, mobile satellite receivers and mobile satellite
radionavigation receivers use antennas that provide relatively low gain and thus must have
very high levels of sensitivity to provide service.  In the fixed satellite services, the
use of high gain directional antennas provides a form of increased system selectivity
because potentially interfering sources not located in the main beam of the antenna are
attenuated.  We seek information on a number of issues concerning interference immunity
guidelines/standards for satellite services, as follows.
- How should satellite receiver interference immunity performance guidelines/standards
provide protection against interference to low received signal levels?
- In the fixed satellite services, should antenna directionality be considered integral to
any receiver interference immunity performance guidelines/standards?
- What parameters of satellite receiver performance should be subject to minimum
guidelines/standards for immunity to interference and how should we establish such
guidelines/standards?
- What values should be specified for the parameters of satellite receiver interference
immunity performance?
- To what extent are the reliability needs of the various types of satellite services
different and how should these differences be treated in establishing minimum performance
guideline/standards?  In addition are there any differences in specifications that are
needed due to differences between fixed and mobile satellite services, and are different
specifications needed for receivers used with low-Earth orbit (LEO) satellite systems than
for receivers needed for GSO systems?

28. Mobile services – Mobile radio services include a broad range of systems operating on
the land, the seas, and in the air.  Specific services range from the mobile systems of
the Commercial Mobile Radio Services, to business radios and “push to talk” operations, to
maritime safety and communications systems, and to aviation communications systems for
commercial and private air traffic.  While these systems vary in their sophistication and
operating ranges, all mobile receivers typically experience varying signal levels
throughout their service area.  For example, where a mobile unit is close to its base
station, both the mobile and base station can operate with signal levels high enough to
support operation.  At the other extreme, when a mobile unit is operating near the edge of
its operating range, both the mobile unit and its base station will receive relatively
weaker signals.  Mobile receivers also face operating complications such as reflected
signals, or “multipath,” and varying levels of undesired and potentially interfering
signals that vary depending on their location and operating frequency.  In addition to
these operating challenges, mobile handsets designers must place a large premium on light
weight and small size.  Thus, mobile systems, and handset units in particular, constitute
one of the most demanding challenges in minimizing interference.

29. We believe it is appropriate to examine mobile receiver immunity performance in the
light of our changing spectrum management policies, and particularly to determine whether
the operation of these devices and spectrum efficiency could be enhanced by development of
minimum receiver performance specifications.  We request comment on the need for mobile
radio immunity guidelines/standards and responses to the following questions on this
issue:
- What minimum interference immunity performance would be appropriate for mobile service
receivers and how those minimums compare to the performance of existing mobile service
receivers?
- Should mobile receivers be subjected to more stringent minimum performance requirements
than receivers for other communications services, given the higher variation in operating
environment conditions experience in the course of mobile operation?  Would the
specifications established under such an approach have an impact on the practical
requirements of mobile equipment for small size and light weight?
- To what extent are the reliability needs of the various types of mobile radio services
different and how should these differences be treated in establishing minimum performance
guidelines/standards?

30. Fixed terrestrial services – Fixed terrestrial services include point-to-point and
point-to-multipoint facilities.  Point-to-point operations usually use highly directional
transmit and receive antennas in order to minimize the potential for receiving
interference and causing interference to others.  Such operations are typically used for
private or common carrier communications links, often as part of a bi-directional system
with a transmitter and receiver at each end of the link.  Point-to-multipoint operations
sometimes use sectorized antennas that transmit in a broadcast-like mode to receivers used
at fixed locations.  The fixed receivers use highly directional antennas that are pointed
at the transmitting antenna.  Point-to-multipoint operations are generally used for
one-way distribution of communications, including, for example, data and video
programming, but two-way voice and data operation are also being developed and used.
Fixed services are generally exposed to a constant fixed interference environment
characterized by the location of specific operations.  We request comment on the need for
interference immunity guidelines/standards for fixed terrestrial receivers in light of our
changing approach to spectrum management, particularly with regard to licensing of
frequencies on a geographic basis.  We seek comment and information on the following
questions concerning minimum interference immunity guidelines/standards for fixed
terrestrial facilities:
- We recognize that in many cases, fixed terrestrial facilities, particularly those used
for point-to-point operations, are designed for high reliability.  Do existing design
features for ensuring high reliability include measures for immunity to interference?
- We also recognize that certain terrestrial point-to-point and point-to-multipoint
receivers are designed to accommodate a wide bandwidth (e.g. Cable Television Relay
Stations that deliver 80 video channels or more.)  The receivers of such systems, by
design, have little interference immunity.  Should immunity guidelines/standards apply to
such receivers?
- Should fixed terrestrial receivers be subjected to less stringent minimum interference
immunity performance requirements than receivers used with other types of services, given
the lesser variation in operating environment conditions generally experienced in the
course of fixed operation?
- If minimum interference immunity performance guidelines/standards would be appropriate
for fixed terrestrial service receivers, what minimum parameter values should be specified
and how would those minimums compare to the performance of existing equipment used with
these services?

31. Broadcast services – The broadcast AM, FM, and television services operate much like
fixed point-to-multipoint services, in that many consumer radios and television sets
receive one-way communications from one or more fixed transmitter sites.  However, the
technical quality of service provided by different models of radio and television
receivers varies to some extent, depending on the design of the device.  These variations
generally reflect manufacturers’ perceptions of user demand balanced against cost/pricing
factors.  For example, the research conducted in response to the low power FM radio
proceeding indicated that lower cost FM receivers may provide more limited service
capabilities.   Generally, allowing manufacturers to determine the performance
capabilities of broadcast receivers, including the performance of their tuning/signal
acquisition sections, historically has yielded product models that provide satisfactory
service for consumers at attractive price levels.

32. Recognizing the above factors, we request comment on the desirability of developing
minimum interference immunity performance specifications for broadcast receivers. In
considering minimum immunity specifications for broadcast receivers, it is not our intent
to reverse our longstanding practice of allowing the market to determine the performance
of broadcast receivers, with the Commission stepping in only where obvious deficiencies
appear that could disrupt the general reception of service.   Rather, we believe that
guidelines, applied on a voluntary basis, could perhaps lead to the marketing of product
models with high interference immunity that consumers could purchase to meet their
performance needs.  Such models might be particularly desirable for consumers to receive
quality services.

33. Recently, the Commission selected in-band-on-channel (IBOC) as the technological
approach for terrestrial digital audio broadcasting and permitted AM and FM radio
broadcasters to commence digital operations on an interim basis using the hybrid IBOC
systems developed by iBiquity Digital Corporation.   It is expected that hybrid analog and
digital audio broadcasting will continue for at least a decade.  In light of this, we ask
the following questions about AM and FM receivers:
- What minimum interference immunity parameters should be established for analog and
analog/digital (hybrid) AM and FM receivers?
- What would be the additional costs to consumers of radio receivers that would provide
interference immunity based on such established guidelines?
- What protection, if any, should be afforded the millions of analog radio receivers now
in use and available for sale?
- How should consumers be informed of differences in radio receiver immunity performance?
Would a recognizable label or symbol on a receiver assist consumers in identifying
equipment with improved performance?

34. We request comment on the following questions relating to the development and
implementation of minimum interference immunity guidelines for broadcast television
receivers:
- What minimum interference immunity parameter values should be specified for DTV
broadcast receivers and how would those minimums compare to the performance of existing
equipment used in this service?
- What would be the additional costs to consumers of DTV receivers that would provide
interference immunity as specified in established guidelines?
- How should consumers be informed of differences in broadcast receiver interference
immunity performance?
35. We also ask for comment on an approach that would provide a fast-track for the
development and implementation of voluntary receiver performance standards for broadcast
DTV receivers.  Television broadcast industry representatives, including the National
Association of Broadcasters (NAB), the Association for Maximum Service Television (MSTV),
and Sinclair Broadcast Group, Inc. (Sinclair), have requested that we impose minimum
performance thresholds on DTV receivers with respect to receiver sensitivity (noise figure
and carrier-to-noise ratio), selectivity (co-channel and adjacent channel
desired-to-undesired signal ratios), dynamic range, and multipath tolerance (adaptive
equalizer performance).   While we have denied these requests in the context of mandatory
performance standards, and are herein dismissing a Petition for Reconsideration in this
regard from Sinclair,  we do believe that it is important that we continue to encourage
manufacturers to provide adequate tuning capability for broadcast DTV signals, to monitor
the performance of DTV receivers as they are introduced to the market, and to intervene if
performance is found lacking in specific areas.  We also believe that DTV receiver
specifications may be useful in this effort as voluntary standards.

36. In this regard, we believe there could be benefit to an approach that would encourage
the development of minimum performance guidelines for DTV receivers and enable
manufacturers to market a special category of receivers that meet such guidelines.  Under
the approach we are suggesting, industry parties representing broadcasters, consumer
electronics manufacturers, consumers, and others as appropriate, would identify the
relevant DTV receiver performance parameters, develop appropriate minimum performance
specifications for those parameters, and publish them.  Receivers that meet these
specifications could then be clearly marked with a recognizable label or symbol to
identify them as complying with industry accepted standards for quality reception.  Such
identification would allow consumers to easily identify high performance products and
manufacturers/ retailers to emphasize the features of those products to encourage
consumers to purchase them.  As part of this approach, the Commission could include
reference to the minimum performance standards in its rules and provide that only models
that comply with these voluntary standards could be marketed as complying with the
industry standards for performance quality or other terminology as might be defined
through our rule making process.  We request comment on this approach and suggestions for
alternative approaches that would provide for implementation of minimum performance
specifications for DTV receivers on a voluntary basis.  We also request comment on the
timeframes that would be required for an industry group to develop recommendations for
improved receiver performance.  We recognize that digital broadcast tuners will soon
become mandatory in many television receivers and the corresponding need to move
expeditiously if these standards are to be available in a timely fashion.  We request
comment on whether an industry group tasked with developing receiver guidelines could be
convened within a three month period, and whether recommendations could be developed
within six to nine months after that. We will also continue to encourage the inclusion of
adequate reception quality in DTV receivers and to monitor the performance of DTV
receivers in this regard through efforts to be conducted by our DTV Task Force, Media
Bureau, and Office of Engineering and Technology.
D. The Impact of Minimum Performance Specifications for Receiver Immunity on Innovation
and the Marketplace

37. Receiver interference immunity performance specifications have the potential to impact
receiver markets in various ways depending on how they are implemented.  At the mildest
level of impact, any performance specifications may create product differentiation that is
generally desirable for consumers/users.  For example, voluntary industry guidelines that
imply, or define, that compliant products are better or more desirable than those that are
not compliant would create product differentiation.  At the same time, the cost of
producing compliant devices might be higher than the cost of producing non-compliant
devices, resulting in higher prices for compliant products.  Consumers/users would
ultimately determine whether the compliant products are successful, based on whether they
would be willing to pay any higher prices that might be charged for the enhanced
performance of those products.  At the highest level of impact, mandatory standards with
which all products must comply could be expected to result in better, presumably more
desirable, products that again might cost more to produce.  However, mandatory standards
could also stifle innovation by restricting the introduction of products with otherwise
desirable new features that are inconsistent with the standards.  The time and expense
associated with changing mandatory standards can also tend to stifle innovation.  The
purchasers of products subject to mandatory standards would decide whether the devices
succeed or fail in the market.  For example, if prices were too high or other features
were adversely affected, consumers/users might shift to an alternative communications
service.  We request comment on the impacts of receiver immunity performance
specifications on innovation and markets for receiver equipment.  Commenting parties are
specifically asked to respond to the following questions:
- What effects would interference immunity performance specifications, in the form of
either voluntary guidelines or mandatory standards, have on innovation in equipment
design, performance (especially with regard to performance not addressed by
specifications) and features?
- What effects would such specifications, again in the form of either voluntary guidelines
or mandatory standards, have on receiver markets in terms of cost of production, price and
availability of equipment, and user demand?
- What aspects of specifications would have the greatest impacts on innovation and markets
and what steps could be taken to minimize or mitigate their impacts.
- To what extent should assessments of the impact on innovation and markets be a factor in
the processes that define guidelines and standards?
E. The Current Receiver Environment

38. The current population of radio receivers generally is subject only to rules limiting
the amount of unintentional emissions they may radiate.   Thus, existing receivers are,
for the most part, built to provide levels of interference immunity as determined
necessary by their designer/manufacturer to provide satisfactory service.  This has, of
course, resulted in a wide range of immunity performance across products used within the
same services and across services.  We seek to develop information describing the
interference immunity characteristics of receivers used in the various radio services.  We
ask for comment and information in response to these specific questions:
- How do existing receivers used with the various radio services perform with regard to
each of the immunity attributes discussed above?
- How many units with these capabilities are currently in service?
- What is the expected remaining service life of existing receivers?
F. Treatment of Existing Receivers

39. There are literally billions of receivers currently in use with the various radio
services.  Depending on the extent to which new receiver interference immunity performance
guidelines/standards might become central to particular spectrum policies, these existing
receivers could pose impacts to our new spectrum management policies ranging from none to
significant.  There are a range of possible approaches that could be adopted for treatment
of existing receivers, and the appropriate approach to apply would depend on a variety of
circumstances.  For example, if we were to adopt the guidelines approach for quality DTV
receivers discussed above and did not change pertinent channel allotment or other
technical criteria, existing DTV receivers and new units of these same or similarly
performing models would pose no impact on our spectrum policies.  On the other hand, if we
were to find it necessary to reclaim a portion of the spectrum used by a service, as we
have done in the case of the broadcast auxiliary service at 1990-2110 MHz, and needed to
support the same number of operations in the remaining spectrum, it might be necessary to
require or provide incentives to users to switch to a new technology or more efficient
receiver design that complies with minimum interference guidelines/standards and to cease
using existing equipment.

40. Looking at this subject more generically, we observe that in situations where we
adopted spectrum policies that assumed receivers performed in accordance with a given set
of interference immunity specifications, it is likely that many of the existing receivers
could continue to provide satisfactory service.  That is, the interference conditions that
would necessitate the use of receivers meeting the applicable guidelines/standards would
not be present everywhere, and in locations where potentially interfering signals were not
present or were present at levels within the capabilities of existing receivers, those
units could provide satisfactory service.  Accordingly, one approach would be to simply
allow users to change to new receivers as they encountered interference.  Of course, where
the service would be of more critical importance, it might be necessary to require
replacement of receivers, and “middle ground” approaches that provided for a transition to
mandatory use of new receivers are possible also.  We request comment and suggestions on
the matter of how to treat existing receivers that do not comply with any new receiver
minimum interference immunity specifications that may be developed, and how the size of
the installed receiver base should affect the development of receiver interference
immunity performance guidelines/standards.  We specifically ask that interested parties
address the criteria that we should use in making determinations to take actions that
would involve the involuntary replacement of receivers, either on a rapid or transitional
basis, for example, in the case of public safety, other services involving safety-of-life
or property, or services involving security of the public or national security.  In the
event such an action were determined to be necessary, what would be an appropriate
phase-in time period?

III. PROCEDURAL MATTERS

41. This is an exempt notice and comment rule making proceeding.  Ex parte presentations
are permitted, except during any Sunshine Agenda period.  See generally 47 C.F.R. §§
1.1200(a), 1.1203, and 1.1204(b).

42. Pursuant to Sections 1.415 and 1.419 of the Commission's rules, 47 C.F.R. §§ 1.415,
1.419, interested parties may file comments on before 75 days after publication in the
Federal Register, and reply comments on or before 105 days after publication in the
Federal Register. Comments may be filed using the Commission's Electronic Comment Filing
System (ECFS) or by filing paper copies. See Electronic Filing of Documents in Rulemaking
Proceedings, 63 Fed. Reg. 24,121 (1998).

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

44. Parties who choose to file by paper must file an original and four copies of each
filing.  If more than one docket or rulemaking number appears in the caption of this
proceeding, commenters must submit two additional copies for each additional docket or
rulemaking number.  All filings must be sent to the Commission's Secretary, Marlene H.
Dortch, Office of the Secretary, Federal Communications Commission, The Portals, 445
Twelfth Street, S.W., Washington, D.C. 20554.

45. Parties who choose to file by paper should also submit their comments on diskette.
These diskettes should be submitted to: Hugh L. Van Tuyl, Office of Engineering and
Technology, Federal Communications Commission, The Portals, 445 Twelfth Street, S.W., Room
7-A133, Washington, D.C. 20554.  Such a submission should be on a 3.5 inch diskette
formatted in an IBM compatible format using Word for Windows or compatible software.  The
diskette should be accompanied by a cover letter and should be submitted in "read only"
mode.  The diskette should be clearly labeled with the commenter's name, proceeding
(including the lead docket number, in this case ET Docket No. 00-47, type of pleading
(comment or reply comment), date of submission, and the name of the electronic file on the
diskette.  The label should also include the following phrase "Disk Copy - Not an
Original."  Each diskette should contain only one party's pleadings, preferably in a
single electronic file.  In addition, commenters must send diskette copies to the
Commission's copy contractor, International Transcription Service, Inc., 1231 20th Street,
N.W., Washington, D.C. 20037.

46. Comments and reply comments will be available for public inspection during regular
business hours in the Reference Information Center (Room CY-A257) of the Federal
Communications Commission, The Portals, 445 Twelfth Street, S.W., Washington, D.C. 20554.
Copies of comments and reply comments are available through the Commission's duplicating
contractor:

47. To request materials in accessible formats for people with disabilities (Braille,
large print, electronic files, audio format),
send an e-mail to [email-masked] or call the Consumer & Governmental Affairs Bureau at
202-418-0531 (voice), 202-418-7365 (TTY)."

48. To make cited sources more easily available to the readers, we are testing the use of
hyperlinks to some FCC documents that are cited in this document.  The World Wide Web
addresses/URLs that we give here were correct at the time this document was prepared but
may change over time.  We also advise that the only definitive text of FCC documents is
the one that is published in the FCC Record.  In case of discrepancy between the
electronic documents cited here and the FCC Record, the version in the FCC Record is
definitive.

IV. ORDERING CLAUSES

49. Accordingly, IT IS ORDERED that, pursuant to Sections 4(i), 301, 302, 303(e), 303(f),
303(r) and 307 of the Communications Act of 1934, as amended, 47 U.S.C. Sections 154(i),
301, 302, 303(e), 303(f), 303(r) and 307, this Notice of Inquiry IS HEREBY ADOPTED.

50. IT IS FURTHER ORDERED that, pursuant to Section 1.429(i) of the Commission’s rules, 47
C.F.R. 1.429(i), the Petition for Reconsideration of the Second Report and Order and
Second Memorandum Opinion and Order in MM Docket No. 00-39 submitted by Sinclair Broadcast
Group, Inc. IS DISMISSED as repetitive for the reasons indicated herein.

51. For further information regarding this Notice of Inquiry, contact Mr. Hugh L. Van
Tuyl, Office of Engineering and Technology, (202) 418-7506, e-mail [email-masked].

FEDERAL COMMUNICATIONS COMMISSION