[Federal Register Volume 69, Number 13 (Wednesday, January 21, 2004)]
[Proposed Rules]
[Pages 2863-2870]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-1192]


-----------------------------------------------------------------------

FEDERAL COMMUNICATIONS COMMISSION

47 CFR Part 15

[ET Docket No. 03-327; FCC 03-289]


Interference Temperature Operation

AGENCY: Federal Communications Commission.

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: This document proposes a new interference temperature model 
for quantifying and managing interference. This new concept could shift 
the current method for assessing interference, basing it on the actual 
radio frequency environment. The Notice of Inquiry requests comment, 
information and research on a number of issues relating to the 
development and use of the interference temperature metric and for 
managing a transition from the current transmitter-based approach to 
the new interference temperature paradigm. The Notice of Proposed Rule 
Making proposes technical rules that would establish interference 
temperature limits and procedures for assessing the interference 
temperature to permit expanded unlicensed operation in the 6525-6700 
MHz and 12.75-13.25 GHz bands.

DATES: Comments must be filed on or before April 5, 2004, and reply 
comments must be filed on or before May 5, 2004.

FOR FURTHER INFORMATION CONTACT: Gary Thayer, (202) 418-2290, John 
Reed, (202) 418-2455, or Ahmed Lahjouji, (202) 418-2061, Office of 
Engineering and Technology.

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Notice 
of Inquiry and Notice of Proposed Rule Making, FCC 03-289, adopted 
November 13, 2003, and released November 28, 2003. The full text of 
this document is available for inspection and copying during regular 
business hours in the FCC Reference Center (Room CY-A257), 445 12th 
Street, SW., Washington, DC 20554. The complete text of this document 
also may be purchased from the Commission's copy contractor, Natek, 
Inc., 236 Massachusetts Avenue, NE., Suite 110, Washington, DC 20002. 
The full text may also be downloaded at: www.fcc.gov. Alternative 
formats are available to persons with disabilities by contacting Brian 
Millin at (202) 418-7426 or TTY (202) 418-7365.
    Pursuant to Sec. Sec.  1.415 or 1.419 of the Commission's rules, 47 
CFR 1.415, 1.419, interested parties may file comments on before April 
5, 2004, and reply comments on or before May 5, 2004. 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 FR 24,121 (1998).
    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 protected], and should include 
the following words in the body of the message, ``get form .'' A sample form and directions will be sent in 
reply. 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, SW., Washington, DC 20554. Filings can be 
sent by hand or messenger delivery, by commercial overnight courier, or 
by first-class or overnight U.S. Postal Service mail (although we 
continue to experience delays in receiving U.S. Postal Service mail). 
The Commission's contractor, Natek, Inc., will receive hand-delivered 
or messenger-delivered paper filings for the Commission's Secretary at 
236 Massachusetts Avenue, NE., Suite 110, Washington, DC 20002. The 
filing hours at this location are 8 a.m. to 7 p.m. All hand deliveries 
must be held together with rubber bands or

[[Page 2864]]

fasteners. Any envelopes must be disposed of before entering the 
building. Commercial overnight mail (other than U.S. Postal Service 
Express Mail and Priority Mail) must be sent to 9300 East Hampton 
Drive, Capitol Heights, MD 20743. U.S. Postal Service first-class mail, 
Express Mail, and Priority Mail should be addressed to 445 12th Street, 
SW., Washington, DC 20554. All filings must be addressed to the 
Commission's Secretary, Marlene H. Dortch, Office of the Secretary, 
Federal Communications Commission.
    Parties who choose to file by paper should also submit their 
comments on diskette. Such a submission should be on a 3.5-inch 
diskette formatted in an IBM compatible format using Microsoft Word 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, 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 
party's pleading, preferably in a single electronic file. In addition, 
commenters must send diskette copies to the Commission's copy 
contractor, Qualex International, Portals II, 445 12th Street, SW., 
Room CY-B402, Washington, DC 20554.

Summary of Notice of Inquiry and Notice of Proposed Rulemaking

    1. The interference temperature concepts introduced in this 
proceeding were initially developed as part of the Commission's 
Spectrum Policy Task Force's (Task Force) work on 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 observed that interference management has become more difficult 
because of the greater density, mobility, and variability of RF 
transmitters and because users have been granted increased flexibility 
in using the spectrum. The Task Force presented several recommendations 
for improving interference management in this changed environment, one 
of which was for the Commission, as a long term strategy, to shift its 
paradigm for assessing interference towards an approach that uses real-
time adaptation based on actual RF environments, and in particular to 
adopt a new ``interference temperature'' metric to quantify and manage 
interference. The Commission's Technical Advisory Committee concluded 
that introduction of the interference temperature concept is a 
reasonable approach to defining harmful interference as a function of 
how the spectrum is actually being used and the designs and margins of 
particular receivers.
    2. In the Notice of Inquiry (Inquiry) phase of this proceeding, the 
Commission requests comment, information, and research on a number of 
issues relating to the development and use of the interference 
temperature metric and for managing a possible transition from the 
current transmitter-based approach for interference management to the 
new interference temperature paradigm. In particular, it poses 
questions concerning the development of the interference temperature 
metric, including the determination of interference temperature limits 
for specific frequency bands, and an assessment of the cumulative noise 
and interference environment in radiofrequency bands, including 
standard methodologies for making assessments, to support the selection 
of those limits. It also requests responses on issues concerning the 
process that would be involved in possible transitioning to the new 
interference control methods in the various frequency bands.
    3. A general implementation of the interference temperature 
approach would involve planning, study of existing RF noise and 
interference levels and other factors, and transition processes that 
would take a substantial amount of time to complete. The Commission 
seeks comment on several steps it could possibly take prior to a 
general implementation that would bring elements of this new paradigm 
into use in the near term and thereby provide a test bed for this model 
that can be studied and evaluated before any broader implementation is 
considered. Therefore, in the Notice of Proposed Rule Making (NPRM) 
phase, the Commission seeks comment on technical rules that would 
establish interference temperature limits and procedures for assessing 
the interference temperature in specific frequency bands used by fixed 
satellite uplinks and by terrestrial fixed point-to-point links. It 
seeks comment on whether the operating circumstances of these 
facilities will allow for simple and reliable measurement of the 
interference temperature at a variety of receive sites under diverse 
situations and circumstances and whether unlicensed devices should be 
allowed to operate at higher power levels than currently allowed by the 
rules, so long as they do not cause the interference temperature to 
exceed the established limits.
    4. Notice of Inquiry. For purposes of this new interference 
management paradigm, interference temperature is defined as a measure 
of the RF power generated by undesired emitters plus noise sources that 
are present in a receiver system (I+N) per unit of bandwidth. More 
specifically, it is the temperature equivalent of this power measured 
in units of ``Kelvin'' (K). In principle, interference temperature 
measurements would be taken at various receiver locations and these 
measurements would be combined to estimate the real-time condition of 
the RF environment. For an interference temperature limit to function 
effectively on an adaptive or real-time basis, a system would be needed 
to measure the interference temperature in the band and communicate 
that information to devices subject to the limit, and a response 
process would also be needed to restrict the operation of devices so as 
to maintain the interference temperature at or below the level of the 
limit. The process could take place within an individual device; at the 
receive sites of a licensed service where the temperature is measured 
and communicated to a central site, where the interference temperature 
profile for the region would be computed; or through a grid of 
monitoring stations that would continuously examine the RF energy 
levels in specified bands, process that data to derive interference 
temperatures, and then broadcast that data to subject transmitters on a 
dedicated frequency, again perhaps with instructions how to respond.
    5. There are several actions that could be taken in the event that 
a device determines that its transmissions would cause the interference 
temperature limit to be exceeded. One approach would be to select a 
different transmitting frequency or, if none were available, to cease 
transmitting until the RF environment changed to a state in which a 
transmission would no longer cause an unacceptable temperature level. 
Another approach would be to reduce the transmitter power and/or change 
the direction or shape of the transmit antenna pattern. These 
capabilities could be implemented by equipping devices with technology 
such as automatic transmitter power control (ATPC) or with the ability 
to electrically re-shape antenna patterns. Combining these approaches, 
a single device could be designed to scan the range of potential 
operating frequencies before transmitting, compute an estimate of the 
amount that their operation would add to the interference temperature 
on each

[[Page 2865]]

frequency, and select among the frequencies that would allow compliant 
operation. The device would monitor the interference temperature and if 
the observed level began approaching or exceeded the limit, could lower 
its power, switch to another frequency, make an antenna adjustment, or 
cease transmitting as conditions might warrant.
    6. The Commission inquires as to the potential costs and benefits 
of a policy establishing an interference temperature. In particular, it 
seeks comment on the likely costs and benefits to licensees, equipment 
manufacturers and other potentially affected entities that could result 
from the use of the interference temperature approach or other 
interference management tools. How would the costs and benefits of an 
interference temperature approach compare to the costs and benefits 
under the Commission's current spectrum policy? In addition, it seeks 
comment on whether and how the interference temperature approach could 
change the current legal framework, regulatory process and general 
enforcement of rules designed to prevent harmful interference. The 
Commission recognizes that this new approach to interference management 
could also present issues of competing rights and interests. However, 
the Task Force Report suggested that clearly defined rights and 
responsibilities for all spectrum users, particularly with respect to 
interference and interference protection, should be considered and 
established to the extent possible and practical. Comment is sought as 
to how the Commission can accomplish this objective and avoid long, 
drawn out interference disputes without detrimentally affecting 
reasonable expectations of all interested parties, including 
expectations regarding the Commission's use of its authority to impose 
conditions, modify licenses and take other steps to promote greater 
access to, and more efficient use of, the spectrum.
    7. Interested parties are invited to submit suggestions for 
enhancing or modifying the general plan presented above or for 
alternative approaches. Noting that the Spectrum Task Force indicated 
that this approach may not be feasible in all bands, commenters are 
also encouraged to present plans that would tailor interference 
temperature to specific services. Comment and suggestions also are 
requested on how to implement such a plan so as to maximize the 
benefits for all parties, that is, to protect licensees from 
interference, provide meaningful benchmark information for equipment 
and system designers/manufacturers, and opportunities for new 
operations, including those of unlicensed devices. Commenting parties 
are also asked to submit information, to the extent it may be 
available, on the value of these benefits to the respective affected 
parties. Comment is requested on how this concept could be used to 
promote more efficient provision of service on a licensed basis and how 
this should be done. More specifically, how could this approach be used 
with licensing approaches that make spectrum available on (1) an 
exclusive basis and (2) a coordinated (shared) basis? Also, what 
approaches would best allow the Commission to transition to spectrum 
management by the interference concept in existing occupied spectrum 
bands? Is there is a general metric that can be used to gauge the 
success of the introduction of the interference temperature devices 
into a new frequency band? Is there a simple metric that can be used to 
gauge the effect of these unlicensed devices upon the incumbent 
services? Should the introduction of interference temperature devices 
be done in stages to ensure that the incumbent services do not suffer 
undue interference? If the introduction were to be done in stages how 
should we limit the initial introduction of interference temperature 
devices to protect the incumbent systems?
    8. Comment is requested on what technological factors should be 
considered in setting interference temperature limits. In general, the 
Commission expects that licensees would prefer to see the interference 
temperature limits in the bands they use set low, while manufacturers 
and users of unlicensed devices would prefer to see these limits set 
high. In this regard, comment is requested on the following questions:
    [sbull] What elements should the Commission consider in setting 
temperature limits for different bands and locations? The Task Force 
suggested that some of the factors to be considered in setting 
temperature limits for a band include: (1) The extent of current use; 
(2) the types of services being offered; (3) the types of licensees 
(for example, public safety); (4) the criticality of services and their 
susceptibility to interference; (5) the state of development of 
technology; and (6) the propagation characteristics of the band. 
Comment is requested on whether these factors are appropriate as well 
as whether other criteria also should be addressed.
    [sbull] In addition, commenters should address what, if any, 
technical factors (e.g., power, field strength at boundary areas, 
antenna requirements, etc.) should be considered in determining the 
interference temperature limits for a given service, frequency band and 
geographic area.
    [sbull] What applications are expected to be filled by unlicensed 
devices operating under the interference temperature metric?
    [sbull] Should factors not specified by the Commission's rules, 
such as typical modulation types for a given service, be considered? If 
so, commenters should identify these factors and the rationale for 
including them.
    [sbull] How should the factors identified be used to determine 
interference temperature limits? That is, should each factor be 
considered equally or are some more important than others? Can an 
equation be developed that uses the identified factors to calculate a 
temperature?
    [sbull] Should all the identified factors be used in all cases? 
Should some factors only be used in some cases? Commenters should 
provide detailed explanations for including or excluding specific 
factors in various analyses.
    [sbull] In bands where several services share the spectrum on a 
primary or secondary basis, should the interference temperature limit 
be based on all the licensed services or only on the service most 
susceptible to interference? How would this be determined? Is the I+N 
of a primary service meaningful to a secondary service?
    [sbull] Are there minimum receiver performance criteria that should 
be considered as a reference in setting interference temperature 
limits? If so, how should the specifications for such a reference 
receiver be developed? Or should the Commission use the worst receiver 
available for a service, or an average receiver, in determining 
temperature limits? How would such a receiver be identified?
    [sbull] To what extent should noise and emissions from existing 
licensed and unlicensed transmitters be a factor in setting 
interference temperature limits? Should the highest current level of 
I+N be used as a minimum meaningful level for the interference 
temperature limit or some other statistical representation of measured 
values?
    [sbull] What entities should be parties to the process of setting 
interference temperature limits? What process should these entities 
follow in determining the temperature limit for a specific band (e.g., 
each entity gets an equal vote, some entities' votes have more weight 
than others, etc.)?
    [sbull] Should the Commission allow private agreements between 
licensed

[[Page 2866]]

and unlicensed users to set interference temperature limits for 
specific bands and frequencies? If so, are there incentives the 
Commission could/should provide to licensees to increase the 
temperature limit over that set by the Commission?
    [sbull] How often should interference temperature limits be 
reviewed?
    [sbull] What processes should the Commission establish for 
modifying interference temperature limits? In such cases, what criteria 
should the Commission consider, how should it weigh those criteria, and 
who should be parties to modification processes?
    [sbull] Are there some services or bands for which the Commission 
should continue to use the current interference protection procedures?
    9. Comment also is requested on the approaches to be used for 
measuring interference temperature on a real-time basis and, in the 
case of temperatures derived from measurements at multiple sites, 
communicating that information to devices that are required to protect 
the limit. In this regard, commenting parties are asked to address 
these questions and issues:
    [sbull] How should the Commission decide on the type of 
interference temperature monitoring to be required to provide real-time 
interference control? Commenters should identify the costs and benefits 
of the three monitoring approaches discussed above and how they relate 
to different services. Commenters are also encouraged to identify other 
monitoring approaches.
    [sbull] Should certain monitoring schemes be specified for certain 
services? Or should this be solely up to the incumbent licensees?
    [sbull] How would monitoring systems be funded and who would be 
responsible for their establishment, operation, and maintenance? 
Commenters should consider vendors or operators of unlicensed devices 
and network services, users of such equipment and services, and perhaps 
licensees.
    [sbull] What principles/criteria would be used to choose the 
location of monitoring sites?
    [sbull] How often should the spectrum be monitored? How large a 
band should be monitored? How should monitoring differ with the type of 
incumbent services present in a band? What bandwidth should be used for 
monitoring (e.g., should measurements be taken with a resolution 
bandwidth of 1 megahertz)?
    [sbull] What detection functions, e.g., root mean squared (RMS), 
peak or average, should be applied in performing noise measurements? 
What integration or averaging time should be employed with these 
measurements? What measurement bandwidths are appropriate?
    [sbull] How would the information from monitoring sites be used to 
determine real-time interference temperature values for a specific band 
in a given geographic area and whether established limits were 
exceeded?
    [sbull] What spectrum resources should be used to convey monitored 
temperature information to devices subject to temperature limits? 
Should dedicated frequencies be used for this purpose?
    10. Comment is requested on the actions that devices subject to 
compliance with interference temperature limits should take if the 
applicable interference temperature limit is exceeded. In particular, 
the Commission seeks comment on the state of development of sensory and 
control equipment that could appropriately govern the action of 
emitters in response to real-time interference temperature data, e.g., 
automatic transmitter power control systems. In addressing the 
following questions, commenters should seek to balance the requirement 
that the temperature limits are not exceeded against the need for 
devices to maintain communications.
    [sbull] What response should a device take if it determines that 
exceeding an established interference noise temperature limit, e.g., 
change frequency, reduce power or place itself in a stand-by mode? 
Should this response be different if the offending device is a stand-
alone device or a device designed to respond to a monitoring system?
    [sbull] Should a graduated response system be used (i.e., should a 
device iteratively take measures to bring the interference temperature 
back into the compliant range or should the strongest measures be taken 
first)?
    [sbull] If many devices are operating, is it possible to assign 
responsibility to specific devices if the temperature limit is exceeded 
and have those devices take measures to ensure that the temperature is 
brought back to a compliant level?
    [sbull] Once an offending device takes measures to bring the 
temperature back to a compliant level, what protocols should be used to 
determine when that device may resume operating?
    [sbull] How should noise temperature limits be enforced? Has 
technology progressed to the level that the limits could be self-
enforced by the radio emitters?
    11. Noise floor measurements. Comment is requested on how to define 
the noise floor and whether there are considerations that would justify 
using slightly different definitions for different bands and/or 
services. Comment, information, and research also are requested on the 
levels of the noise floor in the various frequency bands and how those 
levels vary over time and across geographic regions. While noise floor 
information is useful in administering our interference temperature 
limits, the Commission also recognizes that measuring and monitoring 
the noise floor is a substantial, time-consuming, and, in most cases, 
resource intensive undertaking. It therefore requests comment and 
suggestions for methods to collect this information on a timely, cost 
effective basis or to develop acceptable estimates of this information 
from methods other than continuous direct measurement and monitoring. 
It further requests comment and suggestions for standard methodologies 
for collecting and estimating reliable noise floor data that would be 
consistent with obtaining this data on a timely and cost effective 
basis. Commenters should be specific regarding the techniques used to 
measure the noise floor (e.g., providing information regarding spectrum 
analyzer settings, amount of time monitored, location, etc.)
    12. Determining Harmful Interference. More generally, interference 
can be characterized as an emission from a transmitter that impedes 
reception of a desired signal to a given recipient. However, as noted 
above, interference is only considered harmful if it rises to a certain 
level. In this context, the Commission asks commenters to address the 
following questions:
    [sbull] For a given service in a given frequency band, how much 
interference can be tolerated before it is considered harmful? If the 
determination of harmful interference would be based on specific 
quality of service levels, the Commission requests comment on the 
rationale used to justify the recommended constraints. The commenting 
parties should note the specific frequency bands and services to which 
their comments apply.
    [sbull] When performing interference studies, what assumptions 
should be made regarding operating scenarios? For example, commenters 
should address the duty cycle to be assumed for the desired and 
undesired transmitters. What assumptions should be made about whether 
and/or what percentage of antennas might be aligned under typical 
operating conditions such that there is main beam coupling between 
undesired transmitters and desired receivers?
    [sbull] Can interference from a transmitter be distinguished from 
naturally occurring noise?

[[Page 2867]]

    [sbull] Can a statistical approach to developing temperature limits 
be developed? If so, what parameters need to be developed? How would 
such an approach be applied?
    [sbull] Should the interference temperature limit be set at level 
that quantifies ``harmful interference'' or some other benchmark, or 
``safe-harbor'' level that would constitute less than harmful 
interference?
    13. Notice of Proposed Rule Making. The Commission also seeks 
comment on whether it may be feasible and desirable to begin the 
process of introducing the interference temperature approach on a 
limited basis now in selected bands, even as it begins the study and 
development activities that will support the more general 
implementation of this new paradigm. In this regard, it seeks comment 
on if it is possible to first introduce the interference temperature 
concept on a limited basis without full implementation of real-time 
monitoring of the interference temperature or feedback control of 
transmitters and prior to completion of our studies of the noise floor. 
The approach used in this first step would establish an ``interference 
temperature'' or equivalent metric based upon the communications 
margins needed by the existing licensed operations and apply 
restrictions on unlicensed devices that would minimize the likelihood 
that their operation would result in an increase in interference 
temperature that could exceed the necessary operating margin of the 
licensed services. The proposed restrictions on unlicensed devices 
would include limiting the transmitter output power and requirements to 
use transmit power control (TPC) and dynamic frequency selection (DFS). 
In addition, other requirements that might prove beneficial could 
include limits on the number of unlicensed devices, as well as duty 
cycle restrictions that would insure that these initial interference 
temperature experiments do not cause harmful interference to licensed 
services. As noted, the Commission seeks comment on how these first 
steps could provide additional opportunities for operation of 
unlicensed devices and, perhaps more importantly, provide valuable 
information and experience to guide our formulation of approaches in 
the next phases of this effort.
    14. The Commission proposes to apply the new interference 
temperature approach described herein to unlicensed operation within 
the fixed (FS) and fixed satellite service (FSS) uplink band at 6525-
6700 MHz and the FS, FSS, and BAS/CARS band at 12.75-13.25 GHz 
(excluding 13.15-13.2125 GHz). These bands were chosen because the 
Commission believes they offer the possibility to implement in a 
simplified way the interference temperature concept and approach. 
Comment is sought on the appropriateness of these bands and whether 
additional frequency bands could be suitable for testing the concept of 
interference temperature.
    15. The Commission believes that it is beneficial to look at 
frequencies where FSS satellite uplinks are the predominant use. In 
those instances, the licensed receiver being protected is located on 
the satellite in space. Consequently, the receiver would not be located 
in close proximity to any potentially interfering unlicensed device. 
Given the significant distances involved and the typical satellite 
antenna characteristics, the satellite receiver would ``see'' the 
cumulative effect of the RF signals from all unlicensed devices on the 
ground. Therefore, it is possible to develop a simplified interference 
temperature approach for the satellite receiver and FSS uplink 
operations by aggregating the interference contributions of a large 
number of unlicensed devices over a wide geographic area. Interference 
temperature is a measure of the RF power generated by undesired 
emitters plus noise sources that are present at the input of a receiver 
system (I+N) per unit of bandwidth. Since a satellite-based receiver 
will generally ``see'' large geographic areas of the CONUS, it is 
possible to analytically aggregate the impact of a large number of 
unlicensed devices on the [Delta]T/T criterion. The Commission's 
preliminary analysis indicates that a large number of unlicensed 
devices, over 53 million in the 6525-6700 MHz band and over 369 million 
in the 12.75-13.25 GHz band, operating with EIRP emission levels 
possibly as high as 30 dBm to 36 dBm (1 W to 4 W) could be accommodated 
without exceeding a reasonable [Delta]T/T ``interference temperature'' 
threshold that might be established for FSS systems. Comment is sought 
on an appropriate interference temperature threshold that will afford 
sufficient protection to licensed satellite operations, and in 
particular on whether the 5% value used in the calculations, or another 
value of [Delta]T/T, for example 3% or 1%, would be more appropriate as 
well as on the various assumptions made in the link budget analyses, 
particularly concerning the power emission distributions and other 
technical characteristics of hypothetical unlicensed operations in the 
band. If commenters believe that the analysis is flawed or should be 
conducted differently or by using different assumptions, detailed 
technical explanations and accompanying analysis should be submitted to 
support these claims.
    16. The Commission also believes that bands used for certain 
terrestrial fixed operations would be suitable for our first-step 
implementation of the interference temperature concept. The key 
simplifying benefit of dealing with fixed operations is the fact that 
such operations are generally static and well-defined such that 
reasonable assumptions can be made about their locations and technical 
characteristics. In these bands, fluctuations in the interference 
temperature can be compared to fluctuations in C/(I+N) or (S/I). Once a 
value for the interference threshold of a typical licensed receiver is 
established through consideration of the required signal margins, it is 
possible to utilize a measurement of the ambient fixed signal levels to 
determine whether operation of an unlicensed device of known 
characteristics would exceed the ``interference temperature'' signal 
threshold for a licensed receiver. This transmit/not transmit decision 
could be made in real-time by unlicensed devices that incorporate DFS. 
As implemented here, the DFS threshold of an unlicensed device would be 
adjusted so that the device would not transmit if the detected fixed 
signal level exceeds an established threshold. In this manner, the DFS 
threshold is functionally equivalent to the interference temperature 
limit. Consequently, the transmit/not transmit decision made by the DFS 
feature ensures that the S/I or other chosen metric for licensed 
receivers is not adversely impacted. Based on conservative assumptions, 
the Commission calculates that an unlicensed emitter 100 meters away 
from a 6525-6700 MHz FS receiver should be able to transmit at a power 
level of as much as much as 91 dB to 71 dB higher than the level it 
receives from an FS transmitter without causing harmful interference to 
the associated FS receiver. Similarly, an unlicensed emitter 100 meters 
away from a 12.75-13.25 GHz FS receiver should be able to transmit with 
a power level of as much as 95 dB to 75 dB higher than that received 
from the FS transmitter without causing harmful interference to the 
associated FS receiver. These values could be useful in determining the 
sensitivity of the DFS used with the unlicensed system and seek comment 
in that regard. Comment is requested on the parameters used in these 
calculations and whether other

[[Page 2868]]

approaches could be used to derive appropriate values for an 
interference temperature limit in these bands.
    17. If unlicensed devices were designed to first monitor (e.g., 
listen-before-talk, or ``sniff'') the authorized spectrum to determine 
the levels of existing RF emissions, they could employ DFS to adjust 
their frequency of operation to ensure that operation occurs on 
unoccupied channels. The detection threshold employed within the DFS 
could be adjusted to accommodate the overhead margins for unlicensed 
operations calculated above to ensure that the emissions from the 
unlicensed emitter do not exceed the interference threshold at the 
fixed receiver. Comment is sought on requiring a minimum DFS detection 
threshold of -64 dBm for unlicensed devices operating at output levels 
equal to or exceeding 23 dBm and -62 dBm for unlicensed devices 
operating at output levels below 23 dBm. It is proposed that the 
detection threshold is the received power averaged over 1 millisecond 
referenced to a 0 dBi antenna. Comment is sought on the merits of and 
potential problems that might arise from using this real-time 
monitoring approach. Comments are also sought on alternative methods 
that could be employed to monitor the RF spectrum signal levels and to 
control the interference temperature. Should the threshold be 
referenced to the received power averaged over one millisecond 
referenced to a 0 dBi antenna? Or should some other reference be used? 
Detailed technical comments should be submitted to support commenters' 
positions. Comments also are requested on the bandwidth and time period 
over which the spectrum should be monitored prior to operation. Also, 
commenters should provide details regarding how often the spectrum 
should be monitored after transmission begins. The Commission also 
requests comment on whether the TPC capability should be required to 
reduce power by more than 6 dB below the maximum power? If so, to what 
level? What are the limits of current technology for TPC?
    18. The Commission envisions the maximum unlicensed EIRPs in the 
range of 30 dBm to 36 dBm and believes that sharing between unlicensed 
devices and these incumbent systems is feasible. It observes that these 
systems have been able to share in the past by conducting frequency 
coordination prior to operation. The use of TPC and DFS can 
automatically mimic this function, but in real time as opposed to 
manual human coordination activities. The Commission also proposes that 
unlicensed operations in these bands comply with an undesirable 
emission limit such as that set forth in Sec.  15.407(b)(1) of the 
rules which requires that out-of-band emissions not exceed an EIRP of -
27 dBm/MHz. Based on its experience with this emission level for UNII 
operation, the Commission seeks comment on whether a similar 
requirement will be beneficial when applied to the out-of-band 
emissions of unlicensed operations in the 6525-6700 MHz and 12.75-13.25 
GHz bands. Comment is requested on whether the nature and value of the 
emission limit we propose herein would be appropriate. Commenters 
should discuss whether other out-of-band emission limits should be 
considered as well and whether additional limits should be specified 
immediately outside of the operating channel. For example, commenters 
might wish to address whether another single value limit, or 
alternatively, multiple value limits graduated by frequency offset 
would be more appropriate.
    19. Satellite Monitoring of Spectrum Occupancy. It could be 
possible for satellites to monitor and make available real-time 
measured data such as [Delta]T/T, I/N, C/I, C/(I+N) and I that could 
then be used by individual devices to adjust their operation to ensure 
that they do not interfere with other licensed operations. This 
capability would appear to be feasible since satellites are already 
being used for real-time, remote monitoring of geophysical, 
meteorological and environmental conditions on the surface of the 
earth. Comment is requested on the utility and potential benefits of 
such a real-time monitoring approach in the two bands discussed, as 
well as in any other bands where the interference temperature concept 
could be applied. Comment is requested on how the monitored information 
could be acquired by unlicensed devices. For example, the information 
might be provided via broadcast signals (possibly through a 
subscription service) or other means. One possibility could be that 
unlicensed equipment operating in this manner would consist of systems 
controlled by centralized transmitting stations that relay this 
information. More generally, commenters should indicate whether they 
believe there is interest in such a system and specify how they 
envision such a system might work. Comment also is requested on the 
state of current technology and whether such a system is technically 
feasible today. If such a system were to exist, what data should be 
provided to unlicensed devices? Who should operate such a system?

Initial Regulatory Flexibility Analysis

    20. Initial Regulatory Flexibility Analysis: As required by the 
Regulatory Flexibility Act,\1\ the Commission has prepared this Initial 
Regulatory Flexibility Analysis (IRFA) of the possible significant 
economic impact on small entities by the policies and rules proposed in 
this Notice of Proposed Rule Making (``NPRM''). Written public comments 
are requested on the IRFA. Comments must be identified as responses to 
the IRFA and must be filed by the deadlines for comments on the NPRM 
provided in paragraph 54 of the NOI/NPRM. The Commission shall send a 
copy of this NOI/NPRM, including the IRFA, to the Chief Counsel for 
Advocacy of the Small Business Administration.\2\
---------------------------------------------------------------------------

    \1\ See 5 U.S.C. 603.
    \2\ 5 U.S.C. 603(a).
---------------------------------------------------------------------------

A. Need for, and Objectives of, the Proposed Rules

    21. This rulemaking proposal is initiated to obtain comments 
regarding proposed changes to the regulations for radio frequency 
devices that do not require a license to operate. The Commission seeks 
to determine if its standards should be amended to permit the expanded 
operation of unlicensed devices in the 6525-6700 MHz and 12.75-13.25 
GHz bands. We believe that it may 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. In order to begin our 
exploration of the process that would be involved in a transition to an 
interference temperature regime, we seek comment on specific technical 
guidelines in the NPRM portion of our discussion that we believe can be 
implemented in the near future for selected frequency bands prior to 
any general implementation of interference temperature limits and real-
time adaptation of transmitters to the interference temperature 
environment.

B. Legal Basis

    22. The proposed action is taken 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. 154(i), 301, 302, 303(e), 303(f), 303(r), and 
307.

C. Description and Estimate of the Number of Small Entities to Which 
the Proposed Rules Will Apply

    23. The RFA directs agencies to provide a description of, and where

[[Page 2869]]

feasible, an estimate of the number of small entities that may be 
affected by the proposed rules, if adopted.\3\ The RFA generally 
defines the term ``small entity'' as having the same meaning as the 
terms ``small business,'' ``small organization,'' and ``small 
governmental jurisdiction.'' \4\ In addition, the term ``small 
business'' has the same meaning as the term ``small business concern'' 
under the Small Business Act.\5\ A ``small business concern'' is one 
which: (1) Is independently owned and operated; (2) is not dominant in 
its field of operation; and (3) satisfies any additional criteria 
established by the Small Business Administration (SBA).\6\ Nationwide, 
there are approximately 22.4 million small businesses, total, according 
to the SBA data.\7\
---------------------------------------------------------------------------

    \3\ 5 U.S.C. 603(b)(3).
    \4\ 5 U.S.C. 601(6).
    \5\ 5 U.S.C. 601(3) (incorporating by reference the definition 
of ``small-business concern'' in the Small Business Act, 15 U.S.C. 
632). Pursuant to 5 U.S.C. 601(3), the statutory definition of a 
small business applies ``unless an agency, after consultation with 
the Office of Advocacy of the Small Business Administration and 
after opportunity for public comment, establishes one or more 
definitions of such term which are appropriate to the activities of 
the agency and publishes such definition(s) in the Federal 
Register.''
    \6\ 5 U.S.C. 632.
    \7\ See SBA, Programs and Services, SBA Pamphlet No. CO-0028, at 
pg. 40 (July 2002).
---------------------------------------------------------------------------

    24. A small organization is generally ``any not-for-profit 
enterprise which is independently owned and operated and is not 
dominant in its field.'' \8\ Nationwide, as of 1992, there were 
approximately 275,801 small organizations.\9\ The term ``small 
governmental jurisdiction'' is defined as ``governments of cities, 
towns, townships, villages, school districts, or special districts, 
with a population of less than fifty thousand.'' \10\ As of 1997, there 
were about 87,453 governmental jurisdictions in the United States.\11\ 
This number includes 39,044 county governments, municipalities, and 
townships, of which 37,546 (approximately 96.2%) have populations of 
fewer than 50,000, and of which 1,498 have populations of 50,000 or 
more. Thus, we estimate the number of small governmental jurisdictions 
overall to be 84,098 or fewer.
---------------------------------------------------------------------------

    \8\ 5 U.S.C. 601(4).
    \9\ U.S. Department of Commerce, Bureau of the Census, 1992 
Economic Census, Table 6 (special tabulation of data under contract 
to the Office of Advocacy of the U.S. Small Business 
Administration).
    \10\ 5 U.S.C. 601(5).
    \11\ U.S. Census Bureau, Statistical Abstract of the United 
States: 2000, Section 9, pgs. 299-300, Tables 490 and 492.
---------------------------------------------------------------------------

    25. The SBA has developed a small business size standard for 
wireless firms within the two broad economic census categories of 
Paging \12\ and Cellular and Other Wireless Telecommunications.\13\ 
Under both SBA categories, a wireless business is small if it has 1,500 
or fewer employees. For the census category of Paging, Census Bureau 
data for 1997 show that there were 1320 firms in this category, total, 
that operated for the entire year.\14\ Of this total, 1303 firms had 
employment of 999 or fewer employees, and an additional 17 firms had 
employment of 1,000 employees or more.\15\ Thus, under this category 
and associated small business size standard, the majority of firms can 
be considered small. For the census category Cellular and Other 
Wireless Telecommunications firms, Census Bureau data for 1997 show 
that there were 977 firms in this category, total, that operated for 
the entire year.\16\ Of this total, 965 firms had employment of 999 or 
fewer employees, and an additional 12 firms had employment of 1,000 
employees or more.\17\ Thus, under this second category and size 
standard, the majority of firms can, again, be considered small.
---------------------------------------------------------------------------

    \12\ 13 CFR 121.201, NAICS code 513321 (changed to 517211 in 
October 2002).
    \13\ 13 CFR 121.201, NAICS code 513322 (changed to 517212 in 
October 2002).
    \14\ U.S. Census Bureau, 1997 Economic Census, Subject Series: 
Information, ``Employment Size of Firms Subject to Federal Income 
Tax: 1997,'' Table 5, NAICS code 513321 (issued Oct. 2000).
    \15\ Id. The census data do not provide a more precise estimate 
of the number of firms that have employment of 1,500 or fewer 
employees; the largest category provided is ``Firms with 1,000 
employees or more.''
    \16\ U.S. Census Bureau, 1997 Economic Census, Subject Series: 
Information, ``Employment Size of Firms Subject to Federal Income 
Tax: 1997,'' Table 5, NAICS code 513322 (issued Oct. 2000).
    \17\ Id. The census data do not provide a more precise estimate 
of the number of firms that have employment of 1,500 or fewer 
employees; the largest category provided is ``Firms with 1,000 
employees or more.''
---------------------------------------------------------------------------

    26. The SBA has established a small business size standard for 
Radio and Television Broadcasting and Wireless Communications Equipment 
Manufacturing. Under this standard, firms are considered small if they 
750 or fewer employees.\18\ Census Bureau data for 1997 indicate that, 
for that year, there were a total of 1,215 establishments in this 
category.\19\ Of those, there were 1,150 that had employment under 500, 
and an additional 37 that had employment of 500 to 999. Thus, under 
this size standard, the majority of establishments can be considered 
small.
---------------------------------------------------------------------------

    \18\ 13 CFR 121.201, NAICS code 334220.
    \19\ U.S. Census Bureau, 1977 Economic Census, Industry Series: 
Manufacturing, ``Industry Statistics by Employment Size,'' Table 4, 
NAICS code 334220 (issued August 1999).
---------------------------------------------------------------------------

    27. Satellite Telecommunications. The SBA has developed a small 
business size standard for Satellite Telecommunications Carriers, which 
consists of all such companies having $12.5 million or less in annual 
receipts.\20\ In addition, a second SBA size standard for Other 
Telecommunications includes ``facilities operationally connected with 
one or more terrestrial communications systems and capable of 
transmitting telecommunications to or receiving telecommunications from 
satellite systems,'' \21\ and also has a size standard of annual 
receipts of $12.5 million or less. According to Census Bureau data for 
1997, there were 324 firms in the category Satellite 
Telecommunications, total, that operated for the entire year.\22\ Of 
this total, 273 firms had annual receipts of $5 million to $9,999,999 
and an additional 24 firms had annual receipts of $10 million to 
$24,999,990.\23\ Thus, under this size standard, the majority of firms 
can be considered small. In addition, according to Census Bureau data 
for 1997, there were 439 firms in the category Satellite 
Telecommunications, total, that operated for the entire year.\24\ Of 
this total, 424 firms had annual receipts of $5 million to $9,999,999 
and an additional 6 firms had annual receipts of $10 million to 
$24,999,990.\25\ Thus, under this second size standard, the majority of 
firms can be considered small.
---------------------------------------------------------------------------

    \20\ 13 CFR 121.201, North American Industry Classification 
System (NAICS) code 517410 (formerly 513340).
    \21\ Id. NAICS code 517910 (formerly 513390).
    \22\ U.S. Census Bureau, 1997 Economic Census, Subject Series: 
Information, ``Receipt Size of Firms Subject to Federal Income Tax: 
1997,'' Table 4, NAICS code 517410 (issued Oct. 2000).
    \23\ Id.
    \24\ U.S. Census Bureau, 1997 Economic Census, Subject Series: 
Information, ``Receipt Size of Firms Subject to Federal Income Tax: 
1997,'' Table 4, NAICS code 517910 (issued Oct. 2000).
    \25\ Id.
---------------------------------------------------------------------------

    28. As no party currently is permitted to market or operate 
equipment under the proposed standards, there will be no immediate 
impact on any small entities. The Commission does not have an estimated 
number for the small entities that may currently be capable of 
producing such products but believes that there are only a few in 
existence.

D. Description of Projected Reporting, Recordkeeping and Other 
Compliance Requirements for Small Entities

    29. Part 15 transmitters are already required to be authorized 
under the Commission's certification procedure as a prerequisite to 
marketing and importation. The reporting and

[[Page 2870]]

recordkeeping requirements associated with these equipment 
authorizations would not be changed by the proposals contained in this 
NPRM. These changes to the regulations would permit the introduction of 
an entirely new category of radio transmitters.

E. Steps Taken To Minimize the Significant Economic Impact on Small 
Entities, and Significant Alternatives Considered

    30. The RFA requires an agency to describe any significant, 
specifically small business, alternatives that it has considered in 
reaching its proposed approach, which may include the following four 
alternatives (among others): ``(1) The establishment of differing 
compliance or reporting requirements or timetables that take into 
account the resources available to small entities; (2) the 
clarification, consolidation, or simplification of compliance and 
reporting requirements under the rule for such small entities; (3) the 
use of performance rather than design standards; and (4) an exemption 
from coverage of the rule, or any part thereof, for such small 
entities.'' \26\
---------------------------------------------------------------------------

    \26\ 5 U.S.C. 603(c)(1)-(c)(4).
---------------------------------------------------------------------------

    31. As noted, in order to begin our exploration of the process that 
would be involved in a transition to an interference temperature 
regime, we seek comment on specific technical guidelines in the NPRM 
portion of our discussion that we believe can be implemented in the 
near future for selected frequency bands prior to any general 
implementation of interference temperature limits and real-time 
adaptation of transmitters to the interference temperature environment. 
Currently, no party is permitted to market or operate equipment under 
the proposed standards, so there will be no immediate impact on any 
small entities. One alternative to our proposal is reflected in our 
request for comments on whether it is necessary to preclude expanded 
unlicensed operation in the 650-6675.2 MHz band to protect radio 
astronomy operations or whether suitable technical standards can be 
developed to ensure that interference is not caused. We invite small 
entities to comment on this alternative.

F. Federal Rules That May Duplicate, Overlap, or Conflict With the 
Proposed Rule

    32. None.
    33. The proposed action is authorized under sections 4(i), 301, 
302a, 303(e), 303(f), 303(r) and 307 of the Communications Act of 1934, 
as amended, 47 U.S.C. 154(i), 301, 302, 303(e), 303(f), 303(r) and 307.

Federal Communications Commission.
Marlene H. Dortch,
Secretary.
[FR Doc. 04-1192 Filed 1-20-04; 8:45 am]
BILLING CODE 6712-01-P