Spread Spectrum Transmitters

FEDERAL COMMUNICATIONS COMMISSION

47 CFR Parts 2 and 15

[ET Docket No. 96-8; FCC 96-36]

Spread Spectrum Transmitters

AGENCY: Federal Communications Commission.

ACTION: Proposed rule.

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SUMMARY: By this Notice of Proposed Rule Making (``NPRM''), the

Commission proposes to amend its rules regarding the operation of

spread spectrum transmission systems in the 902-928 MHz, 2400-2483.5

MHz and 5725-5850 MHz bands. For simplicity, these bands will be

referenced in this proposal as 915 MHz, 2450 MHz and 5800 MHz,

respectively. The Commission proposes to eliminate the limit on

directional gain antennas for spread spectrum transmitters operating in

the 5800 MHz band. We are also proposing to reduce, from 50 to 25, the

minimum number of channels required for frequency hopping spread

spectrum systems operating in the 915 MHZ band. These proposals are in

response to Petitions for Rule Making filed by Western Multiplex

Corporation (WMC) and Spectralink Corporation (Spectralink). We are

also denying a Petition for Rule Making from Symbol Technologies, Inc.

(Symbol). Further, the Commission on its own motion proposes a number

of amendments to the spread spectrum regulations to clarify the

existing regulations, to codify existing policies into the rules, and

to update the current definitions. These changes will expand the

ability of equipment manufacturers to develop spread spectrum systems

for unlicensed use.

DATES: Comments must be filed on or before June 19, 1996, and reply

comments must be filed on or before July 19, 1996.

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ADDRESSES: Federal Communications Commission, 1919 M Street, N.W.,

Washington, D.C. 20554.

FOR FURTHER INFORMATION CONTACT: John Reed, Office of Engineering and

Technology, (202) 418-2455.

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Notice

of Proposed Rule Making, ET Docket No. 96-8, FCC 96-36, adopted January

30, 1996, and released February 5, 1996. The full text of this

Commission decision is available for inspection and copying during

normal business hours in the FCC Reference Center (Room 239), 1919 M

Street, N.W., Washington, D.C., and also may be purchased from the

Commission's duplication contractor, International Transcription

Service, (202) 857-3800, 2100 M Street, N.W., Suite 140, Washington

D.C. 20037.

Summary of Notice

1. The Commission is proposing to amend Parts 2 and 15 of the rules

regarding the operation of spread spectrum transmission systems in the

915 MHz, 2450 MHz and 5800 MHz bands. The spread spectrum rules, as

originally adopted, did not specify a limit on antenna gain. At that

time there were few other operators in these bands and little potential

that interference would be caused to other users. Further, we wished to

offer an incentive to spur the development of spread spectrum systems.

These bands, especially the 915 MHz and the 2450 MHz bands, are now

becoming more crowded, particularly with mobile units, increasing the

potential that spread spectrum systems using high gain antennas will

cause harmful interference. In addition to the licensed radio services,

wireless computer local area network systems and various consumer

products, such as cordless telephones, are being used under Part 15 in

the 915 MHz and 2450 MHz bands.

2. Since there are few operators in the 5800 MHz band, the

potential that harmful interference will occur from the use of

directional antennas is much lower. There are also fewer mobile users

in the 5800 MHz band. It is easier to engineer a fixed, point-to-point

system to operate without causing harmful interference problems if the

other stations in that band are fixed in location. Further, the 5800

MHz band is ideal for fixed, point-to-point wideband microwave

operations, the type of applications desired by WMC. Accordingly, the

Commission believes the limit on directional antenna gain should only

be eliminated for spread spectrum systems operating in the 5800 MHz

band. We request comment on this proposal. While we are not inclined to

provide a similar relaxation for the 2450 MHz band, we also ask for

comment on whether we should eliminate the 6 dB limit on directional

antenna gain in this band.

3. The Commission further believes that if spread spectrum

transmitters employing high gain antennas were made available to the

general public, it would be difficult to ensure that these systems are

used only for fixed, point-to-point applications. In addition, high

gain directional antenna systems, because of their narrow transmission

beamwidth and the problems associated with aligning the transmitter

with the receiver site, are not products that would normally be

employed by the general public. Accordingly, we believe that the

marketing of spread spectrum systems employing high gain antennas

should be limited to commercial or industrial operators and exclude

sales to the general public. The Commission further proposes to hold

the operator of a spread spectrum system responsible for ensuring that

the system is operated in a compliant manner. In addition, we propose

to require that the manual supplied with the spread spectrum

transmitter contain language in the installation instructions notifying

the operator of this responsibility.

4. In addition, absent controls regarding the locations and manner

in which spread spectrum transmitters may be used, systems employing

high gain directional antennas could expose the public to potentially

harmful signal levels that exceed the radio frequency exposure limits

in our rules and recommended by various standards-setting

organizations. In order to meet our obligation under the National

Environmental Policy Act, we propose to hold the holder of the grant of

certification for the transmitter, the grantee, responsible for

ensuring that the equipment is designed to minimize exposure of the

public to excessive radio frequency (RF) signal levels. Comments are

requested concerning possible biological hazards from the high

effective radiated power levels that could be emitted from these

systems, any additional methods that can be employed to prevent

unnecessary exposure of the public, and whether we should prescribe the

use of specific means for preventing such exposure.

5. The Commission also seeks comments in two additional areas

regarding the technical standards for spread spectrum transmission

systems operating without a limit on directional antenna gain. The

first of these concerns a reduction in the output power of the

transmitter based on the amount that the increase in directional

antenna gain exceeds the current limit of 6 dBi. We propose that the

output power of a transmitter would need to be decreased by 1 dB for

every 3 dB that the antenna gain exceeds 6 dBi in order to maintain an

``equivalent'' area of interference, i.e., the geographic area over

which interference could result with a directional antenna as compared

to the area obtained with an omnidirectional antenna. See the proposed

new Section 15.274(b)(4) in Appendix B of the NPRM. We are also seeking

comments on whether the rules should specify limits on the horizontal

and vertical beamwidths of antennas used with point-to-point systems.

Certain antenna designs, e.g., a horizontally polarized yagi antenna,

concentrate the signal strength in azimuth (horizontal) but not in

elevation (vertical). A fixed, point-to-point system employing an

antenna with a wide elevation beamwidth that is pointed towards an

office building with multiple floors could result in severe

interference problems to any party in that building who is in line with

the system and is operating in the same band. Several antenna designs

concentrate the radiated signals in both azimuth and elevation, e.g.,

circular dish antennas and stacked yagi antennas. The Commission

believes that any interference problems resulting from excessive

vertical emissions could be resolved if the 3 dB beamwidths, in both

the vertical and the horizontal planes, of the high gain directional

antennas employed with these fixed, point-to-point systems differ by no

more than a factor of two and are proposing such a limit.

6. As SpectraLink observes in its petition, there could be mutual

interference problems between wideband, multilateration LMS systems and

Part 15 frequency hopping spread spectrum systems, and it would be

beneficial if these two operations could avoid sharing the same

spectrum. The modification sought by SpectraLink would appear to

promote frequency sharing within this band. Therefore, the Commission

proposes to amend the rules to permit frequency hopping spread spectrum

systems in the 915 MHz band to use only 25 hopping channels, provided

that those systems employ hopping channel bandwidths of at least 250

kHz and the transmitters operate at a reduced power level. Hopping

systems using channel bandwidths less than 250 kHz already can avoid

operating in the bands used by broadband multilateration LMS systems

and require no decrease in the

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minimum number of hopping channels. For frequency hopping systems

employing channel bandwidths of 250 kHz or greater, we propose to

reduce the minimum number of hopping channels to 25. Consistent with

this plan, we are also proposing to modify the maximum average time of

occupancy on any hopping frequency to 0.4 seconds in any 10 second

period to correspond to the reduction in the number of hopping

channels. Comments are also requested as to whether the rules should

specify a formula for the minimum number of hopping channels based on

the amount by which the bandwidth of the hopping channel exceeds 250

kHz.

7. Further, in order to reduce the potential for interference due

to the smaller number of hopping channels, we propose to require that

frequency hopping spread spectrum systems in the 915 MHz band that use

fewer than 50 hopping channels operate with a maximum peak transmitter

output power of 500 mW.

8. We are also denying the Petition for Rule Making from Symbol to

reduce the minimum number of hopping channels for frequency hopping

spread spectrum systems operating in the 2450 MHz or 5800 MHz bands.

9. There are also several additional regulations concerning Part 15

spread spectrum transmission systems that need to be clarified,

codified or amended. They are Spectral power density, Short duration

transmissions, Measurement of processing gain, Limits on unwanted

emissions, Frequency hopping coordination, External radio frequency

power amplifiers, Transition provisions, Definition of direct sequence

and Pseudorandom sequence and frequency hopping systems. These are

discussed in more detail in the full text of the Commission's NPRM, ET

Docket 96-8.

Initial Regulatory Flexibility Analysis

1. Reason for Action: This rule making proceeding is initiated to

obtain comment regarding proposed changes to the regulations for non-

licensed spread spectrum transmitters.

2. Objectives: The Commission seeks to determine if the standards

should be amended as sought in Petitions for Rule Making filed by WMC,

Symbol and SpectraLink. Additional amendments are also proposed to

clarify the existing regulations and to codify existing policies into

the rules.

3. Legal Basis: The proposed action is authorized under Sections

4(i), 301, 302, 303(e), 303(f), 303(r), 304 and 307 of the

Communications Act of 1934, as amended, 47 U.S.C. Sections 154(i), 301,

302, 303(e), 303(f), 303(r), 304 and 307.

4. Reporting, Recordkeeping and Other Compliance Requirements: Part

15 spread spectrum transmitters are already required to be authorized

under the Commission's certification procedure as a prerequisite to

marketing and importation. The changes proposed in this proceeding

would not change any of the current reporting or recordkeeping

requirements. Further, the proposed regulations add permissible methods

of operation and would not require the modification of any existing

products.

5. Federal Rules Which Overlap, Duplicate or Conflict With These

Rules: None.

6. Description, Potential Impact and Number of Small Entities

Involved: The actions proposed in this proceeding add permissible

methods of operation and will not require the modification of any

existing products. Accordingly, there should be no mandatory impact on

any small entities.

7. Any Significant Alternatives Minimizing the Impact on Small

Entities Consistent with Stated Objectives: None.

List of Subjects

47 CFR Part 2

Communications equipment, Radio.

47 CFR Part 15

Communications equipment, Radio.

Federal Commications Commission.

William F. Caton,

Acting Secretary.

[FR Doc. 96-8386 Filed 4-4-96; 8:45 am]

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