NTIA Reply Comments, In re Amendment of the Commission's Rules to Provide for Unlicensed NII/SUPERNet Operations in the 5 GHz Frequency Range

Docket Number: 
ET Docket 96-102
August 14, 1996


Before the




Washington, D.C. 20554


In the Matter of 
Amendment of the Commission's Rules to
Provide for Unlicensed NII/SUPERNet
Operations in the 5 GHz Frequency Range

) ET Docket No. 96-102
) RM-8648
) RM-8653





The National Telecommunications and Information Administration (NTIA), an Executive Branch agency within the Department of Commerce, is the President's principal adviser on domestic and international telecommunications and information policy. NTIA respectfully replies to comments submitted in response to the Commission's Notice of Proposed Rulemaking (NPRM) in the above-captioned proceeding.(1)


The NPRM seeks comment on the Commission's proposal to make available 350 MHz of spectrum at 5150-5350 MHz and 5725-5875 MHz for use by a new category of non-licensed equipment, called NII/SUPERNet devices. NTIA, as the manager of Federal Government use of radio spectrum -- as well as the President's principal adviser on telecommunication matters and the primary Federal agency working toward the development of the NII -- has a direct interest in the outcome of this proceeding.

NTIA applauds the Commission for initiating this proceeding. Non-licensed wireless technology has the potential to be a major pathway for achieving the Administration's goal of connecting the nation's schools, libraries, and health care providers to the National Information Infrastructure (NII) by the year 2000. While the Commission is also conducting other proceedings to further this important goal, those proceedings primarily address the terms and conditions under which existing services are to be offered by service providers. The new class of non-licensed devices contemplated by the NPRM, on the other hand, could provide an alternative means for educational institutions and other end users to develop innovative, inexpensive, and readily-implemented solutions for meeting their needs for communicating rapidly and efficiently, either within the walls of an organization or across communities.

While NTIA recognizes the great potential offered by this new technology and the importance of making available spectrum for such uses, we wish to emphasize the need to proceed with care in developing appropriate rules permitting widespread use of these non-licensed devices.(2) Such rules would further the development and availability of the NII/SUPERNet devices, increase spectrum efficiency, and minimize interference to and from incumbent Federal users.(3) The Commission should, as part of these rules, ensure that receiver standards are adopted as well as appropriate spectrum sharing protocols. NTIA believes that, if the Commission implements the suggestions proposed in this pleading, such non-licensed NII/SUPERNet devices can be accommodated in the proposed frequency bands.

And, if the Commission does implement such suggestions, NTIA believes it will be possible to permit broader uses than are now proposed by the Commission. The Commission's current proposal would allow for the development of wireless substitutes for inside wiring within structures. It would, however, effectively preclude the use of non-licensed devices using these frequencies either in campus settings or across longer distances. The Commission should increase the permitted effective ranges for these devices within specified portions of the frequency bands under consideration as described further below and begin further study to determine whether such devices operating over longer distances would be compatible with incumbent users. NTIA does not believe, however, that the Commission should delay implementation of initial community networks pending further proceedings.

Such an approach would encourage the development of devices for which many commenters have demonstrated a need.(4) It also would encourage the development of self-regulatory procedures among users of these non-licensed devices.(5) If the Commission's limited proposal is adopted as described in the NPRM, it could preclude any form of community networking and could limit the full potential for these devices. While wireless "inside wiring" is an important application, it is one of a wide range of applications that could and should be supported.


The Administration has established a national goal to connect all of the nation's classrooms, libraries, hospitals, and clinics to the NII by the year 2000.(6) This initiative, which promotes expanded access to computers, teacher training, and the development of compelling educational applications, has the potential to revolutionize our educational system, changing the way teachers teach and students learn. Students will be able to collaborate with their peers around the world, search digital libraries, use remote scientific instruments, and take "field trips" to on-line museums.

As NTIA stated in its letter to the Commission in response to the Apple/WINForum petitions for a rulemaking proceeding, NTIA believes that NII/SUPERNet devices could provide an important means of access to the NII, as wireless networks provide important advantages relative to wired networks, including greater affordability, ease of implementation, and mobility.(7) Schools, hospitals, small businesses, and others would thus have convenient access to communications networks with voice, video, data, and graphics capabilities without the expense and disruption that installing wired systems would require. NTIA has long sought to advance telecommunications and information services for all Americans, and NII/SUPERNet devices would further these goals. They could provide maximum flexibility and choice for users in meeting a wide variety of needs. Use of such devices can be supported while avoiding harmful interference and promoting spectrum efficiency. The Commission should seek to advance that potential to the fullest extent possible.

In addition to connecting schools and other existing public institutions, non-licensed NII/SUPERNet devices have the potential to support new types of services within communities. They could provide a new and vital link within and among individuals, families, social clubs, and community support groups. Except for necessary technical and operational standards, the use of these devices would be unmediated by service providers and thus would allow free rein to the imaginations and needs of user communities.


A. The Commission Should Limit the Extreme Upper and Lower Portions of the Proposed Bands to Low-Powered Non-Licensed Wireless Network Devices But Should Permit Longer Range Community Network Applications in the 5250-5350 and 5725-5850 MHz Bands.

1. Extreme Upper and Lower Portions of the Band

The 5150-5350 and 5725-5875 MHz bands proposed for NII/SUPERNet devices are allocated and used by the Federal Government for various radiodetermination services on a primary basis.

The lower 5150-5250 MHz portion is allocated on a worldwide primary basis for the aeronautical radionavigation service. Although there is experimental use of potential future next-generation systems in the band, there are at present no aeronautical radionavigation systems in this band used on an operational basis. Continued experimentation and possible development of new operational air traffic control systems in this band is expected to continue, however, and safety-of-life considerations therefore preclude any applications in this band that would cause interference. In addition, the 5850-5875 MHz portion of the band is used for the Department of Defense's transportable earth stations and also is being considered to support an element of the Intelligent Transportation System. The Commission must therefore retain the 0.1 Watt e.i.r.p. limit in the 5150-5250 MHz and 5850-5875 MHz subbands.(8) This would permit the development of short-range wireless substitutes for inside wiring within structures, but would preclude the development of longer range networks in these bands.(9)

2. The 5250-5350 and 5725-5850 MHz Bands

NTIA believes that community networking should be an integral part of the NII/SUPERNet concept, and that the remaining (5250-5350 and 5725-5850 MHz) bands are well-suited to this application. In these bands, authorizing community networks having a range comparable to the 1 to 2 kilometer to be used by the European-developed HIPERLAN systems is expected to satisfy many of the wireless LAN's and campus-type community network requirements while also promoting international interoperability. As discussed further below, coexistence between NII/SUPERNet devices and incumbent radar devices is expected to be possible in most areas of the country. Successful operation of community network links, however, will depend on geographic separation from the high-powered radar systems operating in the band.

The 5250-5350 and 5725-5850 MHz portions of the proposed bands are allocated for the Federal radiolocation service and are primarily used by military defense radars. These radars are characterized by very high peak power levels with an e.i.r.p. of up to 110 dBW, pulse modulation, and high-gain antennas that sweep 360 degrees in azimuth. These radar systems are used on land, typically near military facilities, on board ships in coastal areas, on airplanes, and on spacecraft. Billions of dollars have been invested in the research and development of radar systems that operate in these bands. Federal radar systems must continue to operate in these bands to meet essential national defense and training requirements. (Further description of those Federal systems is contained in the attachment to this pleading). All efforts should be made to avoid operating community network links near the military test ranges described in the attachment to this pleading.

Even longer range, 10-30 km, unlicensed community networks in the 5 GHz bands have been proposed. Although the 5725-5850 MHz portion of these bands is a potential candidate for such operation, examining compatibility with existing radar
is a more complex undertaking, which requires greater study and analysis. Further complicating this situation is the ongoing FCC rulemaking proceeding in ET Docket No. 96-8 to authorize long range unlicensed links using spread spectrum techniques in this same band. Compatibility analyses of long range links with existing radar must still be completed for both NII/SUPERNet and spread spectrum systems. The Commission has asked that parties report on the experience gained in operating the devices it authorizes in this proceeding. The Commission should permit experimental tests of the 10-30 km community networks to proceed in the 5725-5850 MHz band and should move to adopt final rules allowing such networks as soon as data becomes available demonstrating the feasibility of such uses.

B. The Commission Must Ensure Adoption of Appropriate Receiver Equipment and Spectrum Sharing Rules as Well as Bandwidth Efficiency Rules

1. Appropriate Receiver Equipment and Spectrum Sharing Rules to Protect All Users in the 5 GHz Band

The use of NII/SUPERNet devices in the 5 GHz bands raises issues both in terms of potential interference from incumbent radars to these devices as well as the potential degradation resulting from the aggregate effects from a large number of these devices to radar performance. While these devices will be authorized on a non-interference basis to the primary radio services in the band, practical considerations suggest that the design of these devices must take into account the existing radio environment in which they will operate.(10) NTIA believes that the adoption of robust receiver design, either by Commission rules or via industry-developed standards, is essential to successful operation of these devices in these bands.

Receiver design techniques that have proven effective against high-power, pulse signals include listen-before-talk techniques, spread spectrum techniques, peak signal limiters, high efficiency error correction, bit interleaving, and error detection with retransmission protocols. Experience has also shown that digital systems operating in or adjacent to bands used by radar systems must incorporate adequate receiver selectivity to achieve satisfactory system performance.

NTIA also supports the Commission's proposal to adopt channel monitoring protocols for NII/SUPERNet data transmission. Such protocols, used in conjunction with dynamic channel selection, can be very effective in minimizing interference, both to and from radars, if implemented in such a way as to adequately detect radar signals typical for the band. The combination of effective receiver design and user protocols can help ensure that spectrum is shared successfully between government and other users. Therefore, the Commission should either mandate receiver standards for the non-licensed devices or require that such standards be adopted by the industry. NTIA plans to be an active participant in WINForum's 5 GHz Sharing Rules Drafting Subcommittee to assist in the development of these rules and protocols.

2. The Commission Should Implement Bandwidth Efficiency Standards

NTIA agrees with the Commission that there should be some value of minimum bandwidth efficiency applicable to the NII/SUPERNet devices. The justification provided by one of the petitioners in this proceeding for the amount of spectrum needed to satisfy the requirement was based on 1 bit per second per Hertz of bandwidth (b/s/Hz). A bandwidth efficiency of 2 b/s/Hz is currently obtainable at a reasonable cost, however. If a modulation scheme that is more bandwidth efficient, such as the /4 Differential Quadrature Phase Shift Keying (/4 DQPSK) adopted by the cellular industry, were employed, the available spectrum could support larger numbers of users. We recognize, of course, that overall spectrum efficiency is measured in more than just bits/second/Hertz, but includes an area element as well.

Adoption of a strict bandwidth efficiency at the outset of a new service, however, may have a dampening effect on its rapid implementation. A more practical approach would be adoption of effective bandwidth efficiency requirements that would come into effect at some reasonable future date such as three years from the conclusion of this rulemaking. This would help to achieve both goals, that of fostering the rapid development of the NII/SUPERNet devices, while also promoting more spectrum-efficient operation as the technology matures.


NTIA applauds the Commission for undertaking this proceeding at this time. The results could have a profound impact on the way individuals, groups and public institutions communicate and on the realization of this nation's goal of universal access for all Americans. NTIA urges the Commission to adopt rules that support a range of in-building and short range community networking configurations (except in the 5150-5250 and 5850-5875 MHz bands, which are suitable for low-power in-building use only), including implementation of rules to ensure receiver standards and protocols to enhance sharing capabilities. Although there may be interference issues, the Commission should not delay unnecessarily development of initial community networks pending further proceedings to study the feasibility of longer range networks in these bands.

Respectfully submitted,


Larry Irving Assistant Secretary for Communications and Information
Barbara S. Wellbery Chief Counsel


Shirl Kinney Deputy Assistant Secretary
Bruce A. Henoch Attorney
Kathryn C. Brown Associate Administrator
Gerald F. Hurt Chief Spectrum Engineering and Analysis Division
Joseph Gattuso Office of Policy Analysis and Development
Edward F. Drocella
James McConnaughey
Charles W. Franz Office of Policy Coordination and Management

National Telecommunications and Information Administration
U.S. Dept. of Commerce, Rm 473
Washington, D.C. 20230
(202) 482-1816
August 14, 1996


1. In re Amendment of the Commission's Rules to Provide for Unlicensed NII/SUPERNet Operations in the 5 GHz Frequency Range, ET Docket No. 96-102, FCC 96-193 (Released May 6, 1996) (Notice of Proposed Rule Making).

2. NTIA has long advocated finding ways that spectrum use efficiency may be increased; sharing of bands between Federal Government users and unlicensed users is a promising way of doing so, so long as interference to and from the incumbent Federal users is minimized.

3. The type of rules that the Commission develops in this proceeding will undoubtedly play a role in other areas as well. There will surely be other Federal-non Federal spectrum sharing opportunities in the future, and protocols and procedures developed here will serve there as they can here, allowing for maximum sharing while minimizing interference to and from incumbent Federal users.

4. See, e.g., Comments of The Benton Foundation and Computer Professionals for Social Responsibility, filed July 15, 1996, at 3-4; and Joint Comments of the National School Boards Association, Media Access Project, National Education Association, American Association of School Administrators, and People for the American Way, filed July 15, 1996, at 3-4.

5. The point-to-point communications links envisioned by some parties as part of community networking appear to be technically feasible within existing microwave allocations. Providers of community networks, however, may be unfamiliar with the regulatory process for obtaining, and intimidated by the cost of, such links. At the same time, many services provided today via licensed point-to-point microwave systems might migrate to the 5 GHz band if the Commission adopts a non-licensed regulatory scheme for that band. Although NTIA supports an allocation of spectrum on a non-licensed basis for community networking, a large scale migration by other users could lead to congestion and interference. This allocation cannot and should not become a substitute for other types of point-to-point microwave communications. NTIA encourages the Commission to streamline its regulatory processes to encourage greater use of all fixed point-to-point microwave bands.

6. To this end, NTIA's Telecommunications and Information Infrastructure Assistance Program (TIIAP) provides matching funds to more than 200 projects throughout the United States to promote community-based network infrastructure development. Moreover, NTIA envisions using schools, libraries, and other "community access centers" (CACs) as a way of furthering universal access to advanced telecommunications and information services. See Reply Comments of the National Telecommunications and Information Administration, CC Docket No. 95-115, filed March 29, 1996, at 23.

7. See Letter from Larry Irving, Assistant Secretary of Commerce for Communications and Information, to Chairman Reed Hundt, RM 8648 and RM 8653, November 2, 1995.

8. The acronym "e.i.r.p." stands for "equivalent isotropic radiated power."

9. This would be compatible with the proposal made by Apple in this proceeding.

10. NTIA's experience has shown that, despite the fact that unlicensed devices operate on a secondary basis and are supposed to accept interference to some extent, consumers do strenuously object when the operation of consumer devices is interfered with by Government operations. There have been many such instances of interference to non-licensed devices, such as garage door openers, cordless telephones, and security devices, that stemmed from a lack of quality in the design of the receiver.