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Rural Wireless Broadband Access in the 3650-3700 MHz Band

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National Telecommunications and Information Administration, U.S. Department of Commerce.


Notice of Inquiry.


The National Telecommunications and Information Administration (NTIA) invites interested parties to review and comment on the questions presented in this Notice to assist NTIA in developing recommendations to the Federal Communications Commission (FCC) on the use of the 3650-3700 MHz band for unlicensed devices. NTIA's specific interest is to ensure the continued protection of operations of Government agencies in this band. In order to ensure that these Federal operations are not adversely affected, NTIA is seeking public comment to explore the merits of frequency and/or geographic avoidance technologies, and other interference-mitigation techniques, and to examine technical requirements to allow compatible unlicensed device usage in the 3650-3700 MHz band. NTIA believes that by making this band available with appropriate regulatory provisions, broadband wireless access would be facilitated in rural areas. NTIA supports the FCC in its efforts to introduce advanced communications to rural areas, and seeks to ensure that the interests of the Federal Government users of spectrum are adequately protected. NTIA has determined that it is important to examine the issues related to the use of unlicensed devices and wireless broadband, and to develop recommendations regarding specific regulations for the use of the 3650-3700 MHz band as a follow-on to the new spectrum allocated at 5 GHz for unlicensed broadband devices.[1] Some initial conclusions about the 3650-3700 MHz band are discussed in NTIA comments in Additional Spectrum for Unlicensed Devices Below 900 MHZ and in the 3 GHz Band proceeding.[2] Comments submitted in this proceeding will be posted on NTIA's website.


Written comments and papers in response to this Notice are requested to be submitted on or before February 27, 2004.


Submit an original and two copies of written comments to the Office of the Chief Counsel, National Telecommunications and Information Administration, U.S. Department of Commerce, 1401 Constitution Avenue, N.W., Room 4713, Attention: Unlicensed Devices Proceeding, Washington, DC 20230. Paper submissions should include a three and one-half inch computer diskette in HTML, ASCII, Word, or WordPerfect format (please specify version). Diskettes should be labeled with the name and organizational affiliation of the filer, and the name of the word processing program used to create the document. Alternatively, comments and papers may be submitted electronically Start Printed Page 4119to Comments submitted via electronic mail also should be submitted in one or more of the formats specified above.

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For questions about this Notice, contact: Charles Glass, National Telecommunications and Information Administration, U.S. Department of Commerce, 1401 Constitution Avenue, N.W., Room 4606, Washington, DC 20230, (202) 482-1896, or

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I. Background

President Bush, in his Technology Agenda and at the Administration's economic summit in Waco, Texas, called for an aggressive expansion of broadband, recognizing the promise of high-speed future communications.[3] In addition to enhancing business efficiencies and broadening commercial opportunities, broadband holds the promise of expanding educational opportunities, improving health care, increasing government responsiveness to its citizens, and generally enhancing our global competitiveness. Thousands of new jobs could result from greater broadband deployment, both directly through network construction, and indirectly through industries related to advanced networks and services. Broadband represents an important potential source of growth and investment for the United States.

The Administration supports technology-neutral solutions where feasible and supports the removal of unnecessary government impediments to competition and broadband deployment. In support of the Administration's policy, NTIA recently has taken steps to promote the expansion of broadband, for example, by spearheading an effort to bring the Defense Department and the U.S. technology industry together to permit devices using Wi-Fi technologies to co-exist with sensitive military radar systems in the 5 GHz frequency band. Within the scope of this proceeding, NTIA intends to facilitate advanced, low-cost wireless broadband deployment in rural areas.

The Federal Communications Commission issued a Proposed Rule and Notice of Inquiry in December 2002 on use of spectrum below 900 MHz and in the 3650-3700 MHz band as new unlicensed spectrum bands.[4] On May 7, 2003, NTIA filed comments in response to the FCC's Notice of Inquiry in the Additional Spectrum for Unlicensed Devices proceeding commending the FCC for seeking to expand the options for unlicensed use of the 3650-3700 MHz band and, particularly, for linking such expanded use to the adoption of new technologies for active-interference avoidance.[5] There appear to be very significant benefits to the economy, businesses, consumers, and government agencies that can be gained by allowing unlicensed devices to operate in certain other bands at higher power levels than currently permitted by the FCC's Part 15 rules for use of the 2.4 and 5.8 GHz bands that are widely used for rural broadband applications. In particular, given the limited bandwidth currently available (50 MHz), the use of higher power usage in the 3650-3700 MHz band could provide great benefit in the rural markets but would most likely have limited success in urban markets due to the lack of supportable competition due to interference given the typical channel width of 20 MHz.

Because of the Federal Government uses of the 3650-3700 MHz band, however, NTIA must address the potential impact that the unlicensed devices could have on critical Federal systems. NTIA identified the 3650-3700 MHz frequency band pursuant to the Omnibus Budget Reconciliation Act of 1993 (OBRA-93) for reallocation from Federal Government use to a mixed-use basis effective January 1999.[6] Under the reallocation, the Federal Government has indefinitely retained systems and operations at three sites where full use of the 3500-3700 MHz by the Department of the Navy is required at these sites on a primary basis. The locations of these sites are: St. Inigoes, MD (38° 10′ 00″N 76° 23′ 00″W); Pascagoula, MS (30° 22′ 00″N 88° 29′ 00″W); and Pensacola, FL (30° 21′ 28″N 87° 16′ 26″W). Original agreement on the mixed use of this band required coordination within an 80 km radius of operation around the Federal Government sites in order to provide adequate protection from harmful interference.

In order to ensure that these Federal operations are not adversely affected, NTIA is seeking public comment to explore the merits of frequency and/or geographic avoidance technologies, and other interference-mitigation techniques, and to examine technical requirements to allow compatible unlicensed device usage in the 3650-3700 MHz band.

II. Invitation to Comment

In conjunction with providing information for consideration by NTIA, interested parties are requested to address the following questions and file comments that will assist NTIA in making a recommendation on the proper use of the 3650-3700 MHz band. In addressing the questions posed in this Notice, commenters should attempt to address both the costs and benefits of a given solution. In doing so, commenters should be mindful not only of the private costs and benefits of an action but also seek to identify any public effects. In gauging such costs and benefits, comments should be as specific as possible. Commenters may include any other issue that is relevant to the areas outlined below. Comments will be posted on NTIA's website at

A. Spectrum Regulatory and Policy Approaches

1. What types of services are appropriate to be offered using the unlicensed devices operating in the band? What limitations or restrictions, if any, should be placed on the use of the band?

2. Given the geographic limitations required to protect the Federal Government sites, can the 3650-3700 MHz band be used effectively for ubiquitous unlicensed operations?

3. Given the apparent interest in higher power and perhaps more robust systems to provide effective broadband access, what type of licensing requirements are appropriate? Would it be practical to introduce some form of notification for certain types of unlicensed systems in order to reduce the potential for causing interference?

4. Would there be a benefit in terms of limiting the potential for interference in this band by using both licensed and unlicensed approaches, perhaps each with different technical characteristics (e.g., licensing higher power devices with low power devices operating as unlicensed devices)?

5. Is there a benefit in tying the use of the 3650-3700 MHz band to Start Printed Page 4120operations in another band? What band combinations would be appropriate? Are there specific technical requirements that would need to be employed (e.g., power, gain, antenna type or height)?

6. Are there developments occurring outside the United States that should be taken into account?

B. Mitigation Measures

1. What mitigation measures can be employed to enhance spectrum utilization while providing protection for the Federal Government sites?

a. Should measures such as Dynamic Frequency Selection, be employed to maximize spectrum reuse and to ensure protection of the Federal Government sites? Would these same measures also assist in reducing interference between unlicensed devices?

b. Can geographic mitigation measures, such as limiting devices sold in the region of the Federal Government sites, work given that the band may be used by unlicensed devices?

c. Should mitigation measures such as location identification be required in the devices that would ensure the device does not operate co-channel with the Federal Government sites? How could this be accomplished?

d. Would these same measures allow other services to operate in the band if they were similarly geographically limited?

2. Discuss other mitigation measures that may be useful or necessary for unlicensed devices to operate in the 3650-3700 MHz band.

C. Technical Issues

1. In the development of specific mitigation measures, it will be important to understand the typical deployment scenario for use by all devices, including wireless broadband devices, in this band. Specifically, discuss the following technical issues with regard to each mitigation measure.

a. The maximum power to be used if the devices operate as licensed and/or unlicensed.

b. The gain the devices employ if licensed or unlicensed.

c. The density that would be expected from deployment of these devices, and, specifically, the kind of modeling scenario that should be used to capture this.

d. The type of antenna technologies (e.g., sector or adaptive antennas) expected to be employed and their heights.

2. What levels of mitigation can be expected from different mitigation approaches?

3. More generally, are there particular technical approaches that should be used for this band to increase its utility to meet rural broadband needs?

Please provide copies of studies, reports, opinions, research or other empirical data referenced in your responses.

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Dated: January 22, 2004.

Kathy D. Smith,

Chief Counsel, National Telecommunications and Information Administration.

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1.  Revision of Parts 2 and 15 to Permit Unlicensed National Information Infrastructure (U-NII) Devices in the 5 GHz Band, ET Docket No. 03-122, Report and Order, FCC 03-287 (released, Nov. 12, 2003).

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2.  Additional Spectrum for Unlicensed Devices Below 900 MHz and in the 3 GHz Band, ET Doc. No. 02-380, Notice of Inquiry, 17 F.C.C.R. 25632 (2002) (Additional Spectrum for Unlicensed Devices). See also, Spectrum for Unlicensed Devices, 68 Fed. Reg. 2730 (Jan. 21, 2003).

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3.  See “Promoting Innovation and Competitiveness: President Bush's Technology Agenda,” available at​infocus/​technology/​tech1.html.

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4.  See Additional Spectrum for Unlicensed Devices, supra note 2.

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5.  Comments of the National Telecommunications and Information Administration, ET Doc. No. 02-380, at 2-3 (May 7, 2003)(NTIA Comments), available at​ntiahome/​fccfilings/​2003/​et02-380comments_​05072003.wpd.htm.

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6.  See National Telecommunications and Information Administration, NTIA Special Publication 95-32, Spectrum Reallocation Final Report (Feb. 1995)(NTIA Final Report); see also Omnibus Budget Reconciliation Act of 1993, Pub.L.No. 103-66, Title VI,§ 6001, 107 Stat. 312, 379 (1993), codified at 47 U.S.C. § 921 et seq. (amended the NTIA Organization Act to add a new part B).

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[FR Doc. 04-1755 Filed 1-27-04; 8:45 am]