Federal Communications Commission

Spectrum Policy Task Force

Report of the Unlicensed Devices and Experimental Licenses Working Group

November 15, 2002

**Unlicensed Devices and Experimental Licenses Working Group**

Michael Marcus, Chair

Jim Burtle

Bruce Franca

Ahmed Lahjouji

Neal McNeil

**[Disclaimer]{.underline}**

The findings and recommendations contained in this Report are those of
the Unlicensed Devices and Experimental Licenses Working Group members,
and do not necessarily reflect the views of the Commission, Commission
management, or the Spectrum Policy Task Force.

Table of Contents

[I. Introduction 4](#introduction)

[II. Unlicensed Devices 4](#unlicensed-devices)

[A. Background 4](#background)

[1. Definition of Unlicensed Devices
4](#definition-of-unlicensed-devices)

[2. Non-interference Requirement 5](#non-interference-requirement)

[3. Uses of Unlicensed Devices 5](#uses-of-unlicensed-devices)

[4. Regulatory History of Unlicensed Operation
7](#regulatory-history-of-unlicensed-operation)

[B. Issues/Findings 11](#issuesfindings)

[1. Need for Additional Unlicensed Bands
11](#need-for-additional-unlicensed-bands)

[2. Protocols/Etiquettes 12](#protocolsetiquettes)

[3. Noise Floor/Aggregation 13](#noise-flooraggregation)

[4. Millimeterwave Bands 14](#millimeterwave-bands)

[5. A Special Case: Wireless ISPs and Point-to-Point Systems
14](#a-special-case-wireless-isps-and-point-to-point-systems)

[C. Unlicensed Device Recommendations
15](#unlicensed-device-recommendations)

[1. Additional Unlicensed Bands 15](#additional-unlicensed-bands)

[2. Protocols/Etiquettes 17](#protocolsetiquettes-1)

[3. Noise Floor/Aggregation 17](#noise-flooraggregation-1)

[4. Millimeterwave Bands 17](#millimeterwave-bands-1)

[5. A Special Case: Wireless ISPs and Point-to-Point Systems
18](#a-special-case-wireless-isps-and-point-to-point-systems-1)

[III. Experimental Licenses 18](#experimental-licenses)

[A. Background 18](#background-1)

[B. Issues and Findings 19](#issues-and-findings)

[1. Interference Definition 19](#interference-definition)

[2. NTIA Coordination 20](#ntia-coordination)

[3. Transparency of Spectrum Available for Experiments
22](#transparency-of-spectrum-available-for-experiments)

[C. Experimental License Recommendations
23](#experimental-license-recommendations)

[IV. Acknowledgements 24](#acknowledgements)

# Introduction

The primary mission of the [U]{.underline}nlicensed Devices and
[E]{.underline}xperimental Licenses [W]{.underline}orking
[G]{.underline}roup ("UEWG" or "Working Group") was to examine the
Commission's rules and policies regarding the operation of Part 15
unlicensed low power transmitting devices and the authorization of
experimental licenses under Part 5. With regard to unlicensed devices,
this review was conducted to determine the current status of unlicensed
device operation, including available spectrum, interference potential,
types of devices, applications, and regulatory models, with a view
towards identifying changes or alternative approaches for regulating
unlicensed devices that might promote more efficient and productive use
of the spectrum. The Experimental Radio Service (ERS) was also examined
to determine the extent to which improvements can be made that would
further encourage innovation and technical development.

The work of the UEWG included examining the comments filed in response
to the *Public* *Notice* issued by the Spectrum Policy Task Force on
June 6, 2002, and the comments and statements made by the participants
at the Public Forum held on August 1, 2002.[^1]

#  {#section .unnumbered}

# Unlicensed Devices

This section provides a definition of unlicensed devices used for the
purposes of this report and presents a discussion of the uses and
benefits of unlicensed devices; a brief history of the development of
the Commission's regulatory framework for unlicensed devices; a brief
discussion of some of the issues/findings with regard to unlicensed
operation; and, the recommendations of the UEWG.

## Background

### Definition of Unlicensed Devices

The rules for unlicensed use of radio frequency (RF) devices are
contained in Part 15 of the Commission's rules.[^2] Three types of
unlicensed devices are defined and regulated under the Part 15 rules:

> *Intentional radiators* - these are devices that intentionally
> generate and emit RF energy by radiation or induction. Typical
> intentional radiators include cordless telephones, remote control
> toys, and other low power transmitters.
>
> *Unintentional radiators* -- these are devices that generate and use
> RF energy within the device but are not intended to emit RF energy by
> radiation or conduction. Typical unintentional radiators include
> devices such as personal computers, printers, disk drives, and other
> digital devices that have internal "clocks" or circuitry used for
> timing within the device, TV interface devices such as VCRs, and
> carrier current system. Radio receivers, such as television receivers
> and AM/FM radios, are unintentional radiators.
>
> *Incidental radiators* -- these are devices that generate RF energy
> during the course of their operation but are not intentionally
> designed to generate or emit that energy. Typical incidental radiators
> include motors and mechanical light switches.

For the purposes of this report, the terms "unlicensed devices" and
"unlicensed consumer devices" are used to refer to intentional radiators
or low power transmitters regulated under Part 15. That is, as
identified in this section of the report, unlicensed devices would
include cordless telephones, remote control toys, etc. Special emphasis
is given to unlicensed devices used for computer and data networking
applications.

### Non-interference Requirement

The basic premise of all Part 15 unlicensed operation is that unlicensed
devices cannot cause interference to licensed operations nor are they
protected from any interference received. The operational parameters for
unlicensed operation are set forth in Section 15.5 of the rules, as
follows:

> \(a\) Persons operating intentional or unintentional radiators shall
> not be deemed to have any vested or recognizable right to continued
> use of any given frequency by virtue of prior registration or
> certification of equipment,
>
> \(b\) Operation of an intentional, unintentional, or incidental
> radiator is subject to the conditions that no harmful interference is
> caused and that interference must be accepted that may be caused by
> the operation of an authorized radio station, by another intentional
> or unintentional radiator, by industrial, scientific and medical (ISM)
> equipment, or by an incidental radiator.
>
> \(c\) The operator of a radio frequency device shall be required to
> cease operating the device upon notification by a Commission
> representative that the device is causing harmful interference.
> Operation shall not resume until the condition causing the harmful
> interference has been corrected.

### Uses of Unlicensed Devices

The availability of spectrum for unlicensed operations has spawned a
significant market for unlicensed devices. These devices range from
simple consumer devices, such as, cordless telephones; remote control
toys; garage door openers; and, baby monitors; to sophisticated business
and commercial applications, such as security systems; inventory control
systems; manufacturing controls; and, business computing networks.

The sales of unlicensed consumer devices are estimated to be in the
billions of dollars per year.[^3] The following table provides
information on a sample of unlicensed consumer devices, based on
Consumer Electronic Association (CEA) data, presently in use in the US:

  --------------------------- ----------------- ------------- ----------------
  **Product**                 **Penetration**   **Number per  **Total
                                                Household**   Installed Base
                                                              (millions)**

  **Cordless Phones**         81.0%             1.50          130.01

  **Garage Door Openers**     40.8%             1.29          56.26

  **Wireless Routers**        NA                NA            1.14

  **Remote Control Toys**     19.5%             2.61          54.47

  **Toy Walkie-talkies (not   15.1%             1.85          29.81
  FRS)**                                                      

  **Baby Monitors**           10.5%             1.38          15.52

  **Home Security Systems**   18.0%             1.10          21.21

  **Keyless Entry Systems for 26.5%             1.40          39.71
  Cars**                                                      
  --------------------------- ----------------- ------------- ----------------

Source: CEA Comments, Docket 02-135, September 30, 2002

The growing popularity of computer networking has stimulated a
heightened interest in unlicensed technology and one of the fastest
growing applications of unlicensed devices is for wireless local area
networks (WLANS). Because most businesses and many homes now have
multiple computers, users often find it desirable to install local area
networks to share resources such as printers, scanners and broadband or
dial-up Internet connections. Developing a local area network using
wireless unlicensed devices can be cost-attractive when compared with
the costs of wired networks and offers the added benefit of instant
portability.

The same spread spectrum technology that has been used for cordless
telephones and other unlicensed devices has been adapted to meet the
surging demand for computer and data networking. Among the more popular
of these unlicensed devices are wireless data devices that operate in
the 2.4 GHz band in accordance with the 802.11b or "Wi-Fi" standards and
protocols developed by the LAN/MAN Standards Committee (LMSC) of the
Institute of Electrical and Electronic Engineers.[^4] Unlicensed devices
operating under the 802.11b/Wi-Fi protocols can be used to link
computers or other digital devices at distances up to about 150 feet and
with data rates of up to 11 Mbps. Other IEEE protocols have recently
been developed, such as 802.11a which operates at 5 GHz and 802.11g
which is an extension of 802.11b, that provide even higher data rates.
Another unlicensed wireless networking standard is HomeRF developed by
the HomeRF Working Group.[^5] This technology provides data capabilities
similar to Wi-Fi but also includes voice capability.

Unlicensed consumer devices are also being developed to provide very
short-range (on the order of 10 meters) wireless "personal area"
networks (WPANs). "Bluetooth," which uses 2.4 GHz spread spectrum
frequency hopping technology, is the dominant WPAN technology at this
time.[^6] Bluetooth devices are beginning to be included in many devices
such as mobile radiotelephones, laptop computers, printers and personal
digital assistants (PDAs) and some experts believe that it could become
a standard feature in many consumer electronic devices. Finally, other
unlicensed technologies such as power line carrier (PLC) systems that
use the electric power lines to transmit data and ultra wideband (UWB)
devices are being developed and hold great promise for providing
consumers with new data and computer networking capabilities.

The Synergy Research Group recently reported that the wireless LAN
market posted its eighth consecutive quarter of double-digit growth and
that total growth from 2000 has been over 150 percent.[^7] It estimates
that over 5 million unlicensed wireless LAN devices were shipped in 2001
and predicts that 21 million Americans will be using wireless LAN
devices by 2007. Gartner Research predicts that by 2006 approximately
\$5.6 billion per year will be spent on Bluetooth technology and more
than 560 million Bluetooth-enabled devices will be purchased by
businesses and consumers.[^8] It is estimated that by 2004 over 45
million business laptop computers will use the Wi-Fi standard.[^9]
Analysts project that by 2007 there will be over 90 million Wi-Fi
enabled devices worldwide and over 40 million people roaming in Wi-Fi
hotspots.[^10]

### Regulatory History of Unlicensed Operation

The rules for unlicensed use of RF devices were first established
approximately sixty years ago.[^11] In 1938, the Commission allowed
devices employing relatively low level RF signals to be operated without
the need for individual licensing as long as their operation caused no
harmful interference to licensed services and the devices did not
generate emissions or field strength levels greater than a specified
level that was chosen to ensure that the device generally would not
cause interference.[^12] Typical kinds of equipment operated under these
regulations were wireless record players, carrier current communication
systems (such as, campus radio systems) and remote control devices.

At the time the original unlicensed standards were adopted, most Part 15
RF devices were designed to operate below 30 MHz and compliance with the
field strength limit was relatively easy to achieve. However, as the
industry designed products intended for operation on higher frequencies,
it became more difficult to meet the field strength limit because the
allowable field strength level decreased as the operating frequency
increased. Over the years the Commission amended and expanded Part 15 of
the rules to permit the non-licensed operation of devices at higher
field strengths in certain higher frequency bands in those cases where
it could be determined that the wide-spread use of such products would
not result in harmful interference to authorized radio services.

In the 1950s, the Commission adopted new technical standards for devices
such as radio receivers and low power transmitters operating in the 27
MHz band and above 70 MHz. In the 1960s through the 1980s, additional
provisions were made under Part 15 to permit the operation of equipment
such as wireless microphones, telemetry systems, garage door openers, TV
interface devices (*e.g.*, video cassette recorders), field disturbance
sensors (*e.g*., anti-pilferage systems for retail stores), auditory
assistance devices, control and security alarm devices, and cordless
telephones.

In 1985, Commission first authorized the operation of non-licensed
spread spectrum systems in the 902-928 MHz, 2400-2483.5 MHz, and
5725-5850 MHz bands under Part 15 of the rules at a power level of 1 W
which was significantly higher than previously permitted unlicensed use
in other bands.[^13] Spread spectrum techniques, developed by the US
military for use during World War II, have high immunity to interference
and low probability of intercept. These same qualities make spread
spectrum systems an attractive technology for consumer use. The
authorization of spread spectrum devices was significant for two
reasons. First, the Industrial, Scientific and Medical (ISM) bands at
902-928 MHz, 2400-2483.5 MHz and 5725-5850 MHz are generally used for
non-communications purposes so concerns about interference to primary
services were small.[^14] Therefore, interference to other licensed and
allocated services was less of a concern and higher power could be
allowed. Second, the ISM frequencies or "unlicensed bands" provided
sufficient bandwidth to permit the development of unlicensed devices
with high data rate capabilities.

The Commission's spread spectrum rules have been highly successful and
have led to the development of a wide range of useful consumer products
and devices. The number of unlicensed devices authorized has grown
steadily over the years. Fueled by the growth of computer networking
applications, such as Wi-Fi, and Bluetooth, the number of spread
spectrum authorizations skyrocketed to 262 in 2000 and then 506 in the
first eight months of 2002. The following graph shows the annual growth
in spread spectrum authorizations.

![](media/image1.wmf){width="3.9270833333333335in"
height="3.2916666666666665in"}

In its 1989 revision of the Part 15 rules, the Commission established
new general emission limits in order to create more flexible
opportunities for the development of new unlicensed transmitting
devices. These more general rules allow the operation of unlicensed
devices for any application provided that the device complies with
specified emission limits. This revision also established new
"restricted bands" to protect certain sensitive radio operations, such
as satellite downlink bands, and federal government operations, and
prohibited transmissions by unlicensed devices in those bands.

The Commission has continued to update and expand the Part 15 rules to
provide new opportunities for unlicensed operation, including the
designation of additional frequency bands for unlicensed use. For
example, in 1993, the Commission designated 20 megahertz for unlicensed
personal communications services (Unlicensed PCS). Ten megahertz was set
aside for asynchronous (primarily data) and ten megahertz was set aside
for isochronous (primarily voice) operations.

In 1995, the Commission made the 59-64 GHz band (millimeterwave band)
available for use by unlicensed devices.[^15] The Commission noted that
the spectrum would be suitable for short-range, high data rate,
broadband applications, such as wireless computer-to-computer
communications, and determined that licensing was not needed because of
the limited potential for interference, due to shorter propagation
distances of these frequencies. Interference potential would also be
limited by the narrow beam width of point-to-point antennas, which are
likely to be operating in this range.

The Part 15 rules were amended in 1998 to provide for operation of
Unlicensed National Information Infrastructure (U-NII) devices in the
5 GHz band (5.15-5.35 GHz and 5.725-5.825 GHz).[^16] Again, the
Commission recognized that developments in a number of different digital
technologies have greatly increased the need to transfer large amounts
of data from one network or system to another. In making this spectrum
available, the Commission concluded that providing additional spectrum
for unlicensed wideband operation would benefit a vast number of users,
including medical, educational, and business/industrial users.

The bands available for unlicensed spread spectrum, Unlicensed PCS,
millimeterwave and U-NII devices are summarized below:

+--------------------+-----------------+------------------------------+
| **Bands**          | **Year          | **Frequencies (MHz)**        |
|                    | Authorized**    |                              |
+--------------------+-----------------+------------------------------+
| ISM/ Spread        | 1985            | 902-928, 2400-2483.5 &       |
| Spectrum           |                 | 5725-5850                    |
+--------------------+-----------------+------------------------------+
| Unlicensed PCS     | 1993            | 1910-1930 & 2390-2400        |
+--------------------+-----------------+------------------------------+
| Millimeterwave     | 1995            | 59,000-64,000                |
+--------------------+-----------------+------------------------------+
| U-NII              | 1998            | 5150-5350 & 5725-5825        |
+--------------------+-----------------+------------------------------+
| Millimeterwave     | 2001            | 57,000-59,000                |
|                    |                 |                              |
| (Expansion)        |                 |                              |
+--------------------+-----------------+------------------------------+

The following chart also indicates that not all unlicensed operations
have been successful.[^17] When the Unlicensed PCS band was created in
1995, it was expected that devices operating in this spectrum would
consist of new cordless telephones, local area networks in offices, and
other kinds of short-range communications. The lack of Unlicensed PCS
devices on the market today may be due to the fact that the band had to
be cleared of existing fixed microwave users for ubiquitous use to occur
and the bandwidths available were relatively modest when compared to
other unlicensed bands. In fact, many of the data applications foreseen
for the Unlicensed PCS bands are now being served by devices operating
in the spread spectrum and U-NII bands.

## Issues/Findings

In some respects, the success of unlicensed operation has been a mixed
blessing. On one hand, unlicensed devices have improved productivity,
provided consumers with new products and services and generally
benefited the U.S. public, its industries, and its economy. On the other
hand, there are concerns that the frequency bands being used by
unlicensed bands will soon become subject to the "tragedy of the
commons," that is, interference and overcrowding; and that this
potential problem coupled with the lack of new spectrum for unlicensed
devices, will stifle innovation and development. The need for "more
unlicensed spectrum" was the most common theme among comments,
workshops, and other discussions with interested parties.

### Need for Additional Unlicensed Bands

Although there were a few parties who questioned this need, the
significant majority of parties commenting on this issue stated that
additional spectrum should be made available for unlicensed use.
Microsoft, for example, urged the Commission to allocate additional
spectrum below 2 GHz and at 5 GHz for unlicensed broadband uses. It
argued that such spectrum could be used to supplement cable and DSL
services and could "jump-start" the creation of competitive wireless
broadband networks in the U.S. Similar support for additional unlicensed
spectrum was expressed by Cingular, Cisco Systems, Inc., the Consumer
Federation of America, Ericsson, Information Technology Industry
Council, Motorola , Proxim, Rural Telecommunications Group, Wireless
Ethernet Compatibility Alliance and others. In their joint reply
comments, the New America Foundation, Consumers Union, *et al,* state
that there is tremendous support in the record for the allocation of
additional frequency bands of spectrum for unlicensed use, particularly
to facilitate broadband wireless networking.

Based on the record, it is generally perceived that the creation of
unlicensed bands has been very successful in allowing the rapid
introduction of new technology and that additional unlicensed bands
would create more such opportunities. However, there was a general lack
of information on how the Commission should create such unlicensed bands
and what priority they should be given relative to other spectrum
requests.

The UEWG finds while it is not practical at this point to develop
estimates of the optimal amount of spectrum that should be provided for
unlicensed operations, it appears that additional spectrum is needed for
unlicensed devices. This is particularly true in light of recent trends
towards increased use of short distance wireless systems, which use
fixed infrastructure to provide end-to-end connectivity. In the large
area wireless systems that existed prior to the formal
regulation/licensing of radio systems it was difficult to control mutual
interference without entry and technical regulation. As radio ranges
become smaller, this justification for licensing becomes less universal.
An ever increasing fraction of today's radio applications have ranges
measured in yards rather than miles.

The UEWG finds that while there is great interest in making available
additional unlicensed spectrum, there is no consensus on how such
spectrum should be obtained, especially at frequencies in the lower
regions of the spectrum , *i.e.*, at 5 GHz and below. The ISM/spread
spectrum bands were rather easy to designate for unlicensed use because
the microwave ovens and other ISM equipment using them made these bands
of little value to most traditional spectrum users. However, having used
this opportunity there is little "low hanging fruit" left for unlicensed
band use. The contentiousness of the ultra wideband rulemaking shows
that even very low power unlicensed use of normally licensed bands can
become very controversial. Thus, any expansion of unlicensed use will
have to pay careful attention to legitimate concerns of other spectrum
users and consider untraditional approaches to obtaining spectrum use.

### Protocols/Etiquettes

After the need for more spectrum, the next most recurring issue was that
of spectrum protocols or etiquettes. Spectrum protocols or etiquettes
are the rules or procedures that must be used by unlicensed devices to
gain access to the spectrum. For example, a simple spectrum etiquette
might require that a device "listen" for a certain period of time to
ensure that the spectrum is unoccupied before it begins transmitting and
that transmissions be limited to a fixed amount of time so that no one
device can occupy the spectrum all of the time. There are currently
mandatory protocols in Part 15 of the rules for Unlicensed PCS
systems.[^18] In addition, industry groups such as IEEE have developed
and are developing voluntary protocols for certain types of unlicensed
devices. For example, IEEE Task Group 802.15.2 is developing recommended
practices for the collaborative use of Wi-Fi and Bluetooth devices in
the 2.4 GHz to ensure that these devices can co-exist and do not
interfere with each other.[^19]

There are theoretical reasons to believe that the overall efficiency and
productive use of a radio band by geographically distributed users with
random time demands (such as might be the case for data communications)
can be improved through the use of a well designed common spectrum
protocol. There are also economic arguments that question whether
marketplace forces alone would result in competing protocols reaching a
stable equilibrium in the marketplace that would maximize the throughput
of a band.

The UEWG therefore finds that the advantage of using a homogeneous set
of protocols in a band to improve overall efficiency seems very
promising and that a government role with regard to setting those
protocols may be appropriate in certain situations. However, real
implementation issues remain in how to recognize when such government
action should be taken and when such action may not be beneficial. While
technology may move ahead at "Internet time," FCC regulations of
necessity are adopted on "APA time," which is considerably slower. Thus,
there is real concern about the possible timeliness of an FCC-adopted
technically detailed protocol and ensuring that protocols are updated as
technology advances. In this regard, the UEWG supports voluntary
industry efforts to the extent possible. Where government intervention
is deemed appropriate, the UEWG suggests that the procedures for the
current Internet protocols could serve as a model. The current Internet
protocols have been very successful. They were first developed and
specified for the ARPANET by its government agency sponsor. However,
this selection was done by the agency funding the project and was not
subject to sometimes lengthy APA procedures. Given that the initial
protocols were in place, the Internet protocols have evolved by a
consensus process without the APA or any formal regulatory process. In
this evolution, Internet protocols have generally kept place with
technology. This is different than the way FCC selected and continues to
maintain protocols in unlicensed PCS. The UEWG believes that there may
be advantages in creating a regulatory framework where wireless
protocols can evolve with changing technology without the delays
associated with APA rulemakings.

### Noise Floor/Aggregation

While the general emissions standards of Section 15.209 have been in the
Commission's rules since 1989, the ultra wideband rulemaking refocused
attention on the issue of whether unlicensed devices are raising the
apparent noise floor to other users of the spectrum and either limiting
their range or raising the cost of infrastructure to serve a given
communication market. There appears to be no available data in the
United States that show what the trends have been with regard to ambient
radio noise or data that show how much of the noise present is due to
unlicensed intentional emitters or any other specific types of
source.[^20] This is no generally accepted methodology for measuring
ambient noise levels and format for recording such information.

The UEWG believes that the absence of such data may serve to prolong the
controversy on this topic and that therefore there would be tangible
benefits for the FCC to cooperate with spectrum users to develop a
long-term spectrum monitoring program to observe trends in ambient noise
levels. Moreover, such data are necessary for implementing Spectrum
Policy Task Force recommendations, most specifically the interference
temperature recommendation. The UEWG believes that a well-designed
multi-year program would have significant benefits and improve spectrum
management in general.

### Millimeterwave Bands

The upper limit of commercially usable spectrum is increasing rapidly
with advances in electronics. PCS radiotelephones operating at 2 GHz and
DBS systems operating at 12 GHz are now common consumer items with
products available in the \$100-200 price range. Prior to 1995, the
highest frequency authorized for non-experimental use was 40 GHz, now it
is 77 GHz and there is a current proposal to extend that to 95 GHz.[^21]

The frequencies above 30 GHz are commonly called "millimeterwave"
frequencies because of their wavelength. At these frequencies, radio
propagation decreases more rapidly with distance than at other
frequencies and antennas that can narrowly focus transmitted energy are
practical and of modest size.

While it is difficult to say what regulatory approach should be used for
millimeter wave spectrum, the physics of this band are so different than
lower bands as to bring into question most of the fundamental precepts
of radio regulation. This results both from the high propagation losses
due to gas absorption of radio signals and the ease of building antennas
with very narrow beams. While licensing is the general presumption at
lower frequencies, the physics of these frequencies appear to justify a
*de novo* approach to considering regulatory schemes on a case-by-case
basis. It may well be reasonable to question whether unlicensed use
should be a major type of use in these higher bands, rather than one
restricted to a small set of bands.

### A Special Case: Wireless ISPs and Point-to-Point Systems

The past decade has seen the creation of unlicensed device-based
telecommunications services. The most recent of these being the wireless
Internet service provider or WISP -- that uses unlicensed equipment to
provide Internet service to third parties. These providers use equipment
that was basically designed and authorized as unlicensed Part 15
wireless LAN equipment. For example, most connectivity with WISPs is
through use of Wi-Fi or IEEE 802.11b devices. In addition, unlicensed
devices are also being used to provide point-to-point microwave service.
Unlicensed systems, for example, are being used by cellular and PCS
providers for emergency and other backhaul operations to connect cell
sites or base stations to the network.

Under Part 15, equipment and devices are approved as a "complete"
system, *i.e*., a transmitter and associated antenna.[^22] This ensures
that the device is not used improperly and does not cause interference
to other services or uses. This approach makes sense for most Part 15
consumer devices. However, in providing service to an area, WISPs often
want to select an antenna that is optimized for local circumstances.
Under present Commission rules, they are limited to antennas sold with
the system. This may limit the available technical choices and result in
higher costs due to lack of effective competition for antennas. In
addition, both WISPs and point-to-point microwave system operators have
suggested that higher power should be permitted for unlicensed operation
in rural areas. The WISP community has indicated, for example, that it
could bring broadband service to more areas if it was allowed higher
power in rural areas.

A number of commenting parties also supported the adoption of additional
technical flexibility for unlicensed use in rural areas. For example,
the Part-15 Organization recommends that more power be permitted in
rural areas to overcome distance and line-of-sight problems. Dr. Krantz
of the University of Wisconsin states that in rural environments
interference in the unlicensed bands is not an issue but communications
range is, and suggests doubling or tripling the effective power in these
cases.

The UEWG finds that the general concept of approving complete systems is
appropriate for consumer-type unlicensed devices. However, this approach
may be overly burdensome and unnecessary for unlicensed device-based
service providers, such as, WISPs and point-to-point microwave system
operators. The UEWG finds that providing additional flexibility for
these specific situations appears justified and should be investigated
further. Further, the UEWG believes that promoting broadband to rural
America is an important Commission objective and that this objective may
be furthered through permitting the use of higher-powered unlicensed
operations in rural areas. Allowing higher power limits in rural areas
for WISPs may be a promising approach to speeding the rural growth of
broadband.

## Unlicensed Device Recommendations

Based on the above discussion, the UEWG makes the following
recommendations with regard to unlicensed devices:

### Additional Unlicensed Bands

-   The UEWG recommends that the following three approaches be explored
    in order to create more spectrum opportunities for unlicensed
    devices:

    -   Permitting unlicensed devices to make opportunistic or dynamic
        use of spectrum occupied by existing services;

    -   Use of the noise temperature concept to permit unlicensed
        devices to underlay the signals of existing services; and,

    -   Creating new "unlicensed bands" by band clearing.

These approaches are described in more detail below.

Opportunistic or dynamic use of existing bands by unlicensed devices
could take place either through protocols to make sure that interference
is very unlikely, or under sharing conditions approved by a band
manager. The protocols approach would require a new type of etiquette
that protects users from interference from unlicensed systems. For
example, an unlicensed device might be required to include a GPS
receiver and related software to verify whether it is in a location
where it is allowed to operate so that its transmissions would not
interfere with licensed users identified in a database. Such an
"opportunistic" approach might be employed in the television bands to
identify "white areas" where individual television channels are not in
use. Alternatively, a "listen-before-talk" or "dynamic" protocol could
be used to determine whether a channel was in operation at a particular
time.[^23]

The other approach is to have sharing conditions managed by a band
manager selected by either the FCC or the licensed user in the band. The
licensed user may choose to designate a band manager in order to derive
revenue from unused capacity in his existing system. Alternatively, an
FCC-selected band might develop techniques for unlicensed sharing with
licensed use and would be responsible for preventing interference.

A second way to allow increased access for unlicensed systems would be
to use underlays beneath the signals of existing users consistent with
avoiding harmful interference. Using the concept of interference
temperature, as described earlier in this report, we might be able to
allow power limits higher than the existing general Part 15 limits in
cases where the unlicensed device senses the interference temperature
and determines that it is below the pre-established maximum . Accurate
noise temperature sensing can be complicated, but simple "worst-case"
measurements can be made to ensure that any errors made are on the safe
side.

The third way to create more unlicensed access is to establish new
"unlicensed bands" by clearing spectrum of existing users. This would
involve moving existing licensees to new bands, probably with some
relocation expenses being paid as has been done in previous examples.
These relocation expenses would have to be raised by some mechanism. We
recommend that a new type of band/protocol manager be considered to
manage the band with control over the protocols to be used in the band.
Funds for existing user relocation could be generated by an auction for
the band/protocol manager or the band/protocol manager could be required
to fund relocation directly out of his user revenues.

The UEWG recommends that the Commission explore these three options and
develop specific proposals for creating additional unlicensed use. The
UEWG suggests that these approaches be tried in sample bands in selected
spectral regions to confirm the ability of unlicensed systems to access
more spectrum without impacting negatively on licensed users.

### Protocols/Etiquettes

-   The UEWG recommends that a new type of 'band/protocol manager" be
    considered for unlicensed operation.

As suggested above, one method for making additional spectrum available
for unlicensed devices is through the use of a band manager. The UEWG
recommends in this regard that a new type of 'band/protocol manager" be
considered. This band/protocol manager would be selected by auction and
would be responsible for ensuring that unlicensed devices did not cause
interference to licensed services in the band. The band manager would be
given the authority to prescribe the protocols to be used by the
unlicensed devices in the band and the ability to approve the
manufacture and sale of all such devices for a specific period of time.
Since the band manager would derive revenue from the sale of authorized
transmitters, he or she would have marketplace incentives to develop
user-friendly, high throughput protocols that would be in demand.
Moreover, the band manager would have the flexibility to modify the
protocols rapidly as technological changes demand. In addition, if such
an approach is adopted, the UEWG recommends that the Commission consider
whether this type of band manager should "sunset" after some number of
years or when some other predetermined criteria, such as total units
sold, is met. Sunsetting may be appropriate when sufficient unlicensed
devices have been sold to create marketplace forces for backward
compatibility or *de facto* standards such that change is unlikely and
the band manager is no longer needed.

### Noise Floor/Aggregation

-   The UEWG recommends that the Commission develop and adopt a standard
    method for measuring the noise floor and develop a process, possibly
    involving public/private partnerships, for recurring monitoring of
    noise floors in various locations to determine the existence of any
    trends.

The lack of reliable information on noise floor in typical radio user
environments and trends in such noise floors has been a complicating
issue in recent policy deliberations and will become more of an issue as
we seek to use spectrum more intensively. A standardized methodology for
measuring ambient noise and a long term process for monitoring trends
will reduce uncertainty in this area, allow for increase spectrum usage,
and ensure that existing users keep the interference protection that
they are entitled to.

### Millimeterwave Bands

-   Recognizing the unique characteristics of the millimeterwave bands,
    the UEWG recommends that all future rule making proceedings for
    terrestrial use of frequencies above 40 GHz include a *de novo*
    review of the costs and benefits of licensing for these frequencies.

As we move into the upper frontier of radio spectrum we should look back
and review what aspects of legacy regulation are related to the
propagation characteristics that existed for bands in use when the
framework was developed. To the degree that new bands have very
different propagation issues, we should consider all possible approaches
to regulation in selecting the approach to use in a particular context
and not be limited by legacy concepts.

### A Special Case: Wireless ISPs and Point-to-Point Systems

-   The UEWG recommends that the Commission consider providing
    additional flexibility for WISPs and point-to-point systems to
    optimize the coverage of their systems and consider permitting
    higher power for rural operations.

The present provisions of Section 15.203 require all intentional emitter
unlicensed systems under Part 15 to be approved as a system with
antennas specified by the grantee (usually the manufacturer or
importer). While this continues to be a reasonable requirement for most
Part 15 systems, it significantly limits the ability of WISPs and
point-to-point systems to build out systems to serve areas with
broadband service as they often have to tailor their antenna selection
to the specific service area and antenna location sites. In 1996, the
Commission faced a similar issue with personal computers in which a
system approach was creating unreasonable burdens in market that had
moved towards "mix and match" subsystems and it adopted Section 15.102,
giving personal computer manufacturers more flexibility than other
unintentional emitter makers. It appears timely now to propose an
analogous rule change for the specific case of WISPs and to allow them
to select antennas and cables provided they verify that the overall
system meets applicable equivalent isotropically radiated power
(e.i.r.p.) limits.

# Experimental Licenses

## Background

Section 303(g) of the Communications Act of 1934, as amended, (the Act)
authorizes the Commission to provide for experimental use of frequencies
and charges the Commission with encouraging the larger and more
effective use of radio in the public interest.[^24] The rules for the
Experimental Radio Service (ERS) are contained in Part 5 of the
Commission's rules.[^25] The primary purpose of the ERS is to provide
for experimental uses of radio frequencies and for development of
techniques and systems that are not otherwise permitted under existing
service rules. The ERS provides opportunity for manufacturers,
inventors, entrepreneurs, and students to experiment with new radio
technologies, new equipment designs, characteristics of radio wave
propagation, or new service concepts related to the use of the radio
spectrum. Some of the uses permitted under Part 5 are: 1)
experimentation for purely scientific purposes; 2) development of
equipment under Federal Government contract, foreign contract, or for
export; 3) technical demonstration of equipment or techniques; 4)
testing of equipment in connection with production or type acceptance,
approval or certification; 5) field strength surveys or demonstration of
equipment to prospective purchasers; 6) development of radio techniques,
equipment, and operational or engineering data related to an existing or
proposed radio service; and 7) provision of communications essential to
research projects where other means of communications are not
available.[^26] While some experimentation and development is also
allowed within existing services, such activities are restricted to
applicants that are eligible to apply for a license in a particular
service and on frequencies that are allocated to that service.[^27]

In order to encourage innovation, the ERS rules provide great
flexibility with regard to allowable frequency range, power, and
emission. However, in order to protect allocated services, ERS licenses
are issued on the condition that experimental operations do not cause
interference to authorized stations of such services, and experimental
operations are not protected from interference from allocated services.
Additionally, ERS stations can be required immediately to cease
operations at the Commission's request, and ERS licenses are subject to
revocation without notice.

The FCC receives about 600 to 1000 ERS applications per year.
Applications for experiments that use frequencies with only non-Federal
Government primary users are solely within the FCC's jurisdiction.
However, about 40% of the applications received deal with frequencies
either shared with Federal Government users or that are assigned only to
such users. In these cases information from the applications must be
sent to the Department of Commerce's National Telecommunications and
Information Administration (NTIA) for coordination, since NTIA is
responsible for frequency management of government users. Experimental
applications that are solely within the FCC's jurisdiction are usually
approved in less than a month.

## Issues and Findings

Only a few of the commenting parties to the Public Notice addressed the
topic of experimental licenses. The principal concern of these parties
appeared to be the delays involved in obtaining an experimental
authorization due to NTIA coordination and difficulties associated with
testing systems being developed for overseas markets with different
allocation plans. This theme was repeated to some degree in the comments
received at the Public Workshop.

### Interference Definition

Experimental licenses are secondary operations and are conditioned on
not causing interference to licensed users.[^28] The UEWG believes that
uncertainty over the definition of interference and its application to
specific cases may result in doubts about whether a given experiment is
practical on an interference-free basis and may act as an impediment to
experimentation. Similarly, incumbent users of spectrum may have
uncertainty about the risk of interference to their operations from
experiments and might raise objections to experiments that pose little
or no risk.[^29] The UEWG finds that reducing uncertainties as to what
constitutes interference will remove a disincentive for experimentation
as well as increase the certainty of conventional licensees who may have
lingering doubts about how much experiments might disrupt their
operations.

### NTIA Coordination

Nortel Networks, in its comments to the Public Notice, stated that in
order to promote the competitiveness of U.S. manufacturers in
international markets the Commission needs to adopt a more relaxed
policy towards experimental licensing or developmental authorizations
for product experimentation, verification and testing. Nortel indicates
that these authorizations would enable development of equipment for
overseas sales, where the regulations may not correspond with those in
the U.S. It argues if manufacturers are unable to perform the necessary
live-air experimentation required to develop or improve products for
markets outside of the U.S., manufacturers may be limited in product
development and thereby inhibited in their ability to compete in the
international marketplace.[^30] Further discussions with Nortel staff
revealed difficulty in obtaining experimental licenses for two systems
that were being developed in their U.S. laboratory for overseas sales
and whose operating frequency was in a band used by the Federal
Government in the U.S. Nortel indicated that in both cases it was unable
to meet with the NTIA's managers who had concerns and try to develop a
modification to their application to limit power, frequency range,
operating hours, operating location, or other parameters in order to
conduct the proposed test without interference to Federal Government
systems.

Motorola indicated similar concerns stating that in some instances,
experimental licenses are necessary to develop and test equipment in the
U.S. that is destined for export sales. According to Motorola, this
requires short-term use of spectrum allocated for Government services
and therefore under the control of the NTIA. Motorola asserts that the
NTIA, under the auspices of the Department of Commerce, should welcome
such use of the spectrum on a coordinated basis, especially when the
outcome is sales of product into foreign countries, which helps the
balance of trade. Motorola further states that it has at times
experienced delays of 12 months or more in obtaining NTIA approval and
delays longer than a few months can be the difference between
successfully deploying product into a foreign marketplace or being
denied critical sales.[^31]

Motorola has also suggested parallel review by FCC of potential
interference of experiments to Federal Government systems, a procedure
for allowing applicants to discuss with NTIA directly any concerns about
applications and to negotiate possible modifications to eliminate
interference threat to Federal systems.[^32] Finally, Motorola suggested
that the Commission set aside at least 50 MHz of spectrum between 2 and
4 GHz "for the development of advanced mobile communications
systems."[^33]

At the public workshop on August 1, 2002, concerns were also raised
about the apparent lack of transparency of the NTIA coordination process
from the point of view of private entities seeking to experiment with
new technology.[^34]

As indicated above, experimental applications that request use of
spectrum that is used exclusively by the Federal Government or shared
with the Federal Government are required to be coordinated with NTIA. In
practice, NTIA refers such applications to the Interdepartmental Radio
Advisory Committee (IRAC), which is composed of all federal agencies
that are major spectrum users.[^35] While many coordination requests are
handled promptly by NTIA, it does appear some applications remain in the
coordination process for a considerable period of time and in some
instances are not resolved after periods in excess of one year.[^36]

The UEWG recognizes that NTIA coordination is necessary to ensure that
experimental operations do not adversely impact important Federal
Government use of the spectrum. It does appear, however, that based on
the public comments and the FCC's experimental licensing data that
certain changes may be warranted.

While experimental licenses in bands with Federal Government assignments
pose a possible interference risk to those systems, such experiments
also have potential benefits for all radio users through facilitating
the development of new technology and also have potential economic
benefit such as increased export sales. The Task Forces suggests that in
considering the coordination of such licenses that NTIA should consider
the benefits of experimentation and the public interest balancing of
them with possible interference risks to Federal Government systems.

Parties have also indicated an interest in being able to communicate
directly with the Federal Government entities concerned about their
pending experimental applications on a more regular basis. They note
that there is no general requirement for Federal Government users to try
to seek a compromise solution to a possible conflict resulting from a
proposed experiment. These parties suggest such contacts would allow
them to explore possible modifications that might lead to mutually
acceptable outcomes such as restricting location, operating power, and
operating hours.[^37] The UEWG recognizes that classification issues
related to certain Federal Government systems may make direct
communication impractical in all cases. Nevertheless, in most instances
it believes that communications between the parties is possible[^38] and
that new procedural and organizational mechanisms should be considered
to improve communications between commercial parties desiring to
implement experiments and Federal users of the spectrum.

### Transparency of Spectrum Available for Experiments

FCC permits experimental license applicants to propose any frequency and
location for their experiment. The FCC license database is publicly
available and can be accessed over the Internet. However, frequency
assignment information for Federal Government users can contain
classified information and this information is not generally available
to potential applicants. This necessity to classify certain Federal
Government frequency assignments complicates the issue of using such
spectrum for experiments. Further, even though the FCC information is
available, the dynamic nature of frequency allocations in recent years
with reallocations between services means potential experimenters who
are not experts in U.S. spectrum use may not be able to identify readily
non-Federal Government spectrum that may be available for experiments on
a non-interfering basis.

The UEWG believes that it would be beneficial to be able to identify
certain frequency bands, locations and times where and when experiments
generally may be conducted. With regard to Federal Government spectrum,
the UEWG believes that one potential approach to this problem deals with
the several bands now in transition from Federal Government use to
non-Federal Government use. Non-government long term commercial
operations cannot be licensed and operated in such bands until the
transitions are completed and government systems are re-located.
However, *all* such bands are not in use *everywhere* in the country *at
all times*. There are likely opportunities for experiments in these
bands on a non-interfering basis today if only one could determine the
appropriate locations, frequencies, and times. The classification of
NTIA assignments makes this difficult, if not nearly impossible, for
private sector entities.

While it would be impractical, and probably a classification problem in
itself, for NTIA to identify all location, frequency, and time
combinations within the transfer bands that are practical for radio
technology experiments, it would be possible with a modest amount of
effort to identify a few areas of the country, preferably urban areas,
where specific transfer bands are not presently in use and are not
expected to be used prior to the final transfer to FCC control. NTIA
could identify a small number of frequency and location pairs that it
could announce and FCC could indicate that experimental license requests
for those bands would not be delayed for lengthy NTIA coordination
purposes, as they had initial pre-approval.

Similarly, FCC could identify locations and blocks of spectrum in bands
with pending reallocations, for example, in TV channels 52-69, in which
interference to ongoing operations is of negligible risk and for which
experimental licenses could likely expect timely approval. While the
basic information on TV channel use is publicly available, small high
tech firms may not be familiar with the structure of the FCC license
databases and the generally accepted propagation models that would be
used to consider the interference risk of a specific experiment.
"Pre-clearing" frequency and location pairs would reduce the risk and
delays associated with applying for an experimental license and might
stimulate radio technology experimentation in entrepreneurial firms.
Alternatively, FCC could publicize what quantitative criteria it will
use for approving experimental licenses in these bands.

## Experimental License Recommendations

The UEWG makes the following recommendations with regard to the
experimental authorization process:

-   Interference and its definition are a key issue in the approval and
    operation of experimental licenses. All Task Force Recommendations
    for narrowing the ambiguities of today's definition will facilitate
    experimentation in the future and lead to a better understanding of
    the rights of both experimenters and other incumbent licenses.

-   The UEWG recommends that NTIA consider a new interface for the
    non-federal Government spectrum users with IRAC members to help
    search for workable compromises for experimental applications and
    suggest that NTIA or DOC to appoint an advocate/ombudsman for the
    private sector.

Most coordination of experimental licenses with NTIA goes smoothly, but
there are a few recurring cases that have problems -- often involving
testing of equipment intended for foreign markets. Yet in order to
compete in world markets, US manufacturers must develop equipment that
is designed for foreign environments. Recognizing that security
classified information about Federal Government spectrum use must
continue to be protected, there is an important need to improve the
transparency of the NTIA coordination process and try harder to search
for solutions to spectrum problems associated with experiments. The UEWG
recommends that NTIA consider a new interface for the non-federal
Government spectrum users with IRAC members to help search for workable
compromises for experimental applications and suggest that NTIA or DOC
to appoint an advocate/ombudsman for the private sector.

-   Identify spectrum from government transfer bands and non-government
    spectrum with pending reallocations where experiments could be
    permitted under certain specified and publicized conditions.

With the ongoing transfer of bands from Federal Government use to FCC
control, it is natural to expect that private entities may be interested
in experimenting with new possible uses for such spectrum. Experimental
licenses in such bands are possible today, but the lack of publicly
available information on present government use of the bands creates an
implicit entry barrier for such experiments. Extensive monitoring by
potential applicants might reveal (location, frequency, time)
combinations that would permit experimentation but the requirement for
such monitoring raises significant entry costs and there is always the
possibility of some contingent use that monitoring would not reveal.
Information from NTIA frequency assignment records would make it easier
to identify such opportunities for experimentation. For example, they
might show that in a specific band scheduled for transfer there are no
Federal Government assignments in Northern California and no
contingencies expected to use that spectrum in that area. However, such
information on Federal Government assignments is not available to the
public due to security classification and security concerns, it is
available to FCC and NTIA; and the UEWG recommends that NTIA and FCC
review Federal Government assignment data in the transfer bands,
identify and announce the availability of combinations of location,
frequency and time that would be available now for experimental
licensing under existing rules. The SPTF believes that such
announcements would lower barriers to experimentation and protect
sensitive information.

Similarly, there is spectrum now under FCC control, *e.g.* TV channels
52-69 that will be reallocated in the near future and can be expected to
be of interest to firms interested in developing new technology. While
information about licenses in these bands is in publicly available
databases, there is little easily available information about how to
find this information and what criteria the FCC would use for
considering an experimental license in such bands. The SPTF recommends
that the Commission compile and make publicly available background
information for potential experimenters in these bands concerning
reallocation schedules, current licensees, and technical criteria for
avoiding interference such as required D/U ratios with existing
licensees and acceptable propagation models.

# Acknowledgements

The Working Group would like to thank the commenting parties that
addressed the issues discussed here and the speakers at the August 1^st^
workshop. The collegial contributions of the other 3 working groups are
gratefully acknowledged. This effort would have been impossible without
effective continuous interaction of all 4 working groups. Neal McNeil
provided much of the historical material on unlicensed devices, Jim
Burtle provided information on the operation of the experimental
licensing provess, Alan Stilwell, Bruce Romano, Lisa Gaisford, and Ahmed
Lahjouji helped with comment summaries, and Tom Mooring helped with
final preparation of the report. Finally, the working group acknowledges
the outstanding leadership of Paul Kolodzy who established a schedule,
brought people together, and kept things on target throughout the Task
Force deliberations.

[^1]: The comments and transcripts of the Public Forum are on file in
    Docket 02-135.

[^2]: 47 CFR Part 15.

[^3]: Comments of CEA in Docket No. 02-135, dated September 30, 2002.

[^4]: The IEEE is a non-profit technical professional organization.
    Among other activities, the organization develops technical
    standards. The IEEE 802.11 Working Group is charged with developing
    standards for wireless local area networking devices. Examples of
    Wi-Fi products can be seen at
    <http://www.weca.net/OpenSection/certified_products.asp?TID=2> .

[^5]: The HomeRF Working Group was formed in 1998 and includes more than
    70 companies from the personal computer, consumer electronics and
    related fields. *See* <http://www.homerf.org/products/> for an
    example of HomeRF devices.

[^6]: Bluetooth was created by Ericsson in 1994. The Bluetooth Special
    Interest Group (SIG) was formed in 1998 to develop and promote an
    open standard for short-range wireless networking. Charter members
    of the SIG include Ericsson, Intel, IBM, Nokia and Toshiba.
    Information on Bluetooth products can be seen at
    <http://www.bluetooth.com/tech/products.asp> .

[^7]: Comments of Consumer Electronics Association, Docket No. 02-135,
    p. 3

[^8]: *Communications Daily*, September 5, 2002.

[^9]: Roger O. Crockett, *et al*., "All Net, All the Time," *Business
    Week*, April 29, 2002

[^10]: Elizabeth V. Mooney, "Joltage Aspires to be Wi-Fi Heavyweight,"
    *RCR Wireless News*, April 22, 2002, at 20.

[^11]: This historical discussion is based on the *Report and Order* in
    Docket 87-389, 4 FCC Rcd 3493 (1989).

[^12]: The limit applied to these early devices was 15 microvolts/meter
    (uV/m) at a distance equivalent to the wavelength of the operating
    frequency divided by 2π.

[^13]: Spread spectrum communication systems use special modulation
    techniques that spread the energy of the signal being transmitted
    over a very wide bandwidth. The information to be conveyed is
    modulated onto a carrier by some conventional techniques, usually a
    digital modulation technique, and the bandwidth of the signal is
    deliberately widened by means of a spreading function. The spreading
    technique used in the transmitter is duplicated in the receiver to
    enable detection and decoding of the signal. Spread spectrum systems
    offer two important technological advantages over conventional
    transmission schemes. First, the spreading reduces the power density
    of the signal at any given frequency within the transmitted
    bandwidth, thereby reducing the probability of causing interference
    to other signals occupying the same spectrum. Second, the signal
    processing in spread spectrum systems tends to suppress undesired
    signals, thereby enabling such systems to tolerate strong
    interfering signals.

[^14]: For example, these bands are used for industrial purposes,
    including heating and sealing materials, such as plastics, during
    manufacturing processes. The 2400 MHz band is the location of most,
    if not all, current and recent model consumer microwave ovens.

[^15]: This band was later expanded to cover 57-64 GHz. *See* 47 C.F.R.
    §15.255.

[^16]: The 5 GHz band is also used on an unlicensed basis in Europe.
    However, the available spectrum, referred to as the HiperLAN2 bands,
    is slightly different than the US U-NII bands. While the two share
    the 5.15-5.25 GHz portion, the HiperLAN2 upper band stretches from
    5.470-5.725 GHz.

[^17]: The 57-64 GHz band is not shown in the chart. It is a relatively
    recently authorized band and is in an area of the spectrum with
    great technological challenges. Two models were authorized in this
    band in 2000 and three models have been authorized so far in 2002.

[^18]: *See* §§15.321, 15.323. Some parties have stated that the
    specific nature of this protocol is one reason why this service has
    met with little commercial success.

[^19]: The IEEE Task Group is looking at adaptive power control,
    adaptive frequency hopping and other collaborative approaches to
    reduce interference.

[^20]: The FCC's Technological Advisory Committee has observed, " Until
    \[noise floor\] information is organized and analyzed, the FCC will
    not have a firm basis for deciding whether current noise standards
    are too tight, too loose, or maybe even just right." *Sixth Meeting
    Report of the TAC* at 9.

[^21]: *See* *Notice of Proposed Rulemaking* in Docket No*.* 02-289.

[^22]: Devices may be approved for use with several antenna and output
    power combinations.

[^23]: While traditional "listen-before-talk" systems suffer from the
    problem in which a receiver fails to detect the presence of a
    transmission because of a poor propagation path, a very sensitive
    feature detector receiver could eliminate much if not all of this
    problem. For example, if the signal strength in a room varies by 30
    dB due to multipath and wall attenuation, a feature detector inside
    that room with a sensitivity 40 dB below demodulation sensitivity
    could reliably detect the presence of a receivable signal anywhere
    in the room on a given frequency. A conventional listen-before-talk
    receiver would give a false indication of no signal in the locations
    where the signal level was very low due to location variability.

    Feature detector technology was developed by military electronics
    researchers to detect the presence of covert communications systems.
    This technology increases the signal detection sensitivity of a
    receiver, which in this case means the sensitivity at which the
    receiver can detect the presence of a signal - not the sensitivity
    at which the receiver can demodulate the signal successfully. The
    detector works by developing a waveform in the receiver that is
    related to a key signal parameter, such as the baud rate of the
    transmission, and then integrating that waveform to improve the
    signal-to-noise ratio of the waveform. In the case of DTV, for
    example, the symbol rate is precisely defined as 10.76 Mbps and this
    could readily serve as a feature to detect. Feature detectors trade
    off detection time versus sensitivity. For example, integrating over
    a million baud, could improve the detection threshold by 60 dB over
    what a receiver could do if it had to demodulate every baud. *See*
    Gardner, W.A., \"Signal interception: a unifying theoretical
    framework for feature detection*,\" IEEE Trans. Comm.*, 1988, Vol.
    *36*, pp. 897-906.

[^24]: *See* Section 303(g) of the Communications Act of 1934, as
    amended, 47 U.S.C. § 303(g). This discussion is based in part on the
    NPRM in Docket 96-256, 11 FCC Rcd 20130 (1996).

[^25]: *See* 47 CFR Part 5.

[^26]: *See* §5.3, Scope of service.

[^27]: *See*, for example, developmental rules for broadcast stations
    under Subpart A of Part 74.

[^28]: As secondary services, experimental licenses must also accept
    interference from licensed users.

[^29]: In an unrelated rulemaking, one party has requested that the
    Commission "clarify that if any experiment causes *any*
    interference, the experimental licensee must eliminate the
    interference or cease operations" and that the Commission require 30
    day advance notification of any radio experiment so that incumbent
    licensees can "independently" review proposal. Reply Comments of
    BellSouth Corporation, CC Docket 98-094, August 5, 1998 at p.6

[^30]: Comments of Nortel Networks, ET Docket 02-135, at p. 2.

[^31]: "A White Paper on Future Federal Communications Commission
    Spectrum Policy," Motorola, ET Docket 02-135, August 30, 2002 at p.
    26.

[^32]: Motorola, *op. cit.* at p. 26.

[^33]: *Ibid.* p. 25

[^34]: See Transcript of August 1, 2002 Workshop on Unlicensed Spectrum
    and Experimental Licenses, Remarks of David Reed at p. 201 and
    DeWayne Hendricks at p. 207. Hendricks stated the following at the
    workshop:

    > "It seems to me that without transparency, and whether the
    > government owning so much of the spectrum, we\'re going to
    > continue to have that problem, and it\'s going to hurt \-- you
    > know, it\'s going to basically mean that anybody who either
    > competes with the government, or might have a better use for the
    > spectrum than the government, or might even be developing
    > technology that would ultimately benefit the government, has an
    > extremely high burden to bear of many years of delay, if nothing
    > else, while they try to work through a non-transparent system."

[^35]: NTIA coordination is actually carried out by the IRAC Frequency
    Assignment Subcommittee (FAS).

[^36]: OET's Experimental Branch has recently instituted a procedure in
    which new applications that not successfully coordinated in one year
    are dismissed without prejudice.

[^37]: Another tool for resolving conflicts in extreme case might be
    real time coordination of experimental operations with the Federal
    Government user of the spectrum and immediate cessation in case of
    interference or unexpected increases in the Federal Government
    user's need for spectrum due to local emergencies. This approach
    appears to have been used in some past cases.

[^38]: In some cases where direct communications between an applicant
    and the affected Federal Government user is not possible due to
    classified information, NTIA might wish to act as or appoint a third
    party to act as a go between.