[Federal Register Volume 64, Number 138 (Tuesday, July 20, 1999)]
[Proposed Rules]
[Pages 38877-38878]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-18428]


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FEDERAL COMMUNICATIONS COMMISSION

47 CFR Part 15

[ET Docket 99-231; FCC 99-149]


Spread Spectrum Devices

AGENCY: Federal Communications Commission.

ACTION: Proposed rule.

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SUMMARY: This document proposes to revise the rules for frequency 
hopping systems operating in the 2.4 GHz band (2400-2483.5 MHz) to 
allow for wider operational bandwidths. We also propose to refine the 
method for measuring the processing gain of direct sequence systems. 
This action is taken to facilitate the continued development and 
deployment of spread spectrum technology, particularly for high data 
rate wireless applications.

DATES: Comments must be filed on or before October 4, 1999, and reply 
comments must be filed on or before November 2, 1999.

ADDRESSES: Address all comments concerning this proposed rule to the 
Commission's Secretary, Magalie Roman Salas, Office of the Secretary, 
Federal Communications Commission, 445 12th Street SW, Washington, DC 
20554.

FOR FURTHER INFORMATION CONTACT: Neal McNeil, Office of Engineering and 
Technology, (202) 418-2408, TTY (202) 418-2989, e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Notice 
of Proposed Rule Making, ET Docket 99-231, FCC 99-149, adopted June 21, 
1999, and released June 24, 1999. The full text of this document is 
available for inspection and copying during regular business hours in 
the FCC Reference Center, (Room TW-A306) 445 12th Street SW, 
Washington, DC. The complete text of this document also may be 
purchased from the Commission's duplication contractor, International 
Transcription Service, Inc., (202) 857-3800, 1231 20th Street, NW, 
Washington, DC 20036.

Summary of Notice of Proposed Rulemaking

    1. Frequency Hopping Systems. Section 15.247 of the Commission's 
rules, permits frequency hopping spread spectrum systems to operate in 
the 2.4 GHz band with a maximum output power of 30 dBm (1 watt). The 
rules specify that frequency hopping systems operating in this spectrum 
must use a minimum of 75 hopping channels with each channel having a 20 
dB bandwidth not exceeding 1 MHz. The average time of occupancy on any 
frequency must not be greater than 0.4 second within a 30 second 
period.
    2. The Home RF Working Group (``HRFWG'') filed a request that the 
Commission interpret section 15.247 to allow frequency hopping systems 
in the 2.4 GHz band to operate with 3 MHz and 5 MHz bandwidths. HRFWG 
proposes to allow systems with bandwidths of up to 3 MHz to operate 
with output power no more than 25 dBm and channel occupancy time no 
greater than 0.05 second per hop. Each of the 75 channels will be used 
at least once during a 3.75 sec period. Like existing 1 MHz systems, 
the average time of occupancy on any channel will not be greater than 
0.4 second within a 30 second period. HRFWG's proposal will allow 
systems using 5 MHz channels to operate with output power no more than 
23 dBm and channel occupancy time no greater than 0.02 second per hop. 
Each of the 75 hopping channels will be used at least once during a 1.5 
second period. Again, the average occupancy time on any channel will 
remain 0.4 second or less per 30 second period.
    3. We do not believe these proposed rule changes will result in any 
significant increase in interference to direct sequence spread spectrum 
systems. We recognize that spectrum occupancy of frequency hopping 
systems in the 2.4 GHz band will increase as a result of the proposed 
changes. The existing rules require a minimum of 75 hopping channels 
each with a bandwidth of no more than 1 MHz. Given the 83.5 MHz of 
spectrum available in the 2.4 GHz band, no frequency is used more than 
once in the hop sequence. However, if the channel bandwidth is 
increased to 3 MHz or 5 MHz, overlapping channels will be needed to 
accommodate 75 hops. Accordingly, the average time of occupancy on any 
one frequency will increase. However, it appears that the proposed 
reduction in output power and time of occupancy would offset any 
potential increase in interference. Further, we observe that 
manufacturers of direct sequence systems that are concerned about 
interference can improve the robustness of their systems by increasing 
processing gain.
    4. Direct Sequence Processing Gain. Under section 15.247(e) of the 
Commission's rules, direct sequence systems are required to exhibit a 
processing gain of at least 10 dB. The 10 dB minimum was established to 
ensure that a system is, in fact, spread spectrum in nature. Generally, 
systems employing a spreading rate of at least 10 chips/symbol meet the 
10 dB processing gain requirement. The number of chips per symbol 
refers to the ratio of spreading imposed by the direct sequence high 
speed spreading code.
    5. The Commission allows processing gain to be determined by either 
of two methods. The first is a direct measurement taken from the 
demodulated output of the receiver. The processing gain is calculated 
as the ratio, in dB, of the signal-to-noise ratio with the system 
spreading code turned off to the signal-to-noise ratio with the system 
spreading code turned on. Alternatively, in cases where the design of 
the system does not permit de-activation of the spreading code, an

[[Page 38878]]

indirect measurement of processing gain, based on receiver jamming 
margin (the ``CW jamming margin method''), is permitted. See 15 CFR 
15.247(e)(2). The receiver jamming margin is representative of the 
ability of the receiver to reject other radio signals appearing on the 
same frequency. The test is generally viewed as an accurate measure of 
processing gain for systems employing spreading rates of at least 10 
chips/symbol. However, in cases where the spreading rate is less, the 
results of the test are questionable.
    6. The jamming margin test is based on use of a CW signal as an 
interference source. Some spread spectrum device manufacturers have 
suggested that the use of a Guassian noise interferer, instead of a CW 
interferer, would be more suitable for the jamming margin test. After 
reviewing the various submissions, we tentatively conclude that a 
Guassian interferer is likely to give a more accurate measure of 
processing gain because it is more closely related to the noise a 
system would encounter in a real-world environment. Therefore, we 
propose to permit the use of a Guassian interferer for determining 
receiver jamming margin.
    7. The Commission has also received comments from manufacturers 
asserting that the current jamming margin test, along with a 
mathematical calculation of processing gain, should be required to 
demonstrate that systems using fewer than 10 chips per symbol are in 
compliance with the rules. The mathematical calculation would take into 
account the ``coding gain'' achieved by modulating and spreading of the 
baseband signal. We believe that this approach will provide greater 
assurance that the systems are in compliance. Accordingly, we propose 
to amend the rules to require manufacturers of direct sequence spread 
spectrum systems that use a spreading rate less than 10 chips per 
symbol to submit the results of the jamming margin test as well as a 
calculation of processing gain to verify compliance. Omnidirectional 
antenna operating at 250 mV/m.

Initial Regulatory Flexibility Analysis

    8. As required by Section 603 of the Regulatory Flexibility Act, 5 
U.S.C. 603, the Commission has prepared an Initial Regulatory 
Flexibility Analysis (IRFA) of the expected significant economic impact 
on small entities by the policies and rules proposed in this Notice of 
Proposed Rule Making (``NPRM''). Written public comments are requested 
on the IRFA. Comments must be identified as responses to the IRFA and 
must be filed by the deadlines for comments on the NPRM. The Commission 
shall send a copy of this NPRM, including the IRFA, to the Chief 
Counsel for Advocacy of the Small Business Administration in accordance 
with paragraph 603(a) of the Regulatory Flexibility Act.

A. Reason for Action

    9. This rule making proceeding is initiated to obtain comment 
regarding proposed changes to the regulations for non-licensed 
transmitters.

B. Legal Basis

    10. The proposed action is taken pursuant to Sections 4(i), 301, 
302, 303(e), 303(f), and 303(r) of the Communications Act of 1934, as 
amended, 47 U.S.C. 154(i), 301, 302, 303(e), 303(f), and 303(r).

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

    11. For the purposes of this NPRM, the RFA defines a ``small 
business'' to be the same as a ``small business concern'' under the 
Small Business Act, 15 U.S.C. 632, unless the Commission has developed 
one or more definitions that are appropriate to its activities. See 5 
U.S.C. 601(3). Under the Small Business Act, a ``small business 
concern'' is one that: (1) is independently owned and operated; (2) is 
not dominant in its field of operation; and (3) meets any additional 
criteria established by the Small Business Administration (SBA). See 15 
U.S.C. 632. SBA has defined a small business for Standard Industrial 
Classification (SIC) category 4812 (Radiotelephone Communications) to 
be small entities when they have fewer than 1500 employees. See 13 CFR 
121.201. Given this definition, nearly all such companies are 
considered small.

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

    12. Part 15 transmitters are already required to be authorized 
under the Commission's certification procedure as a prerequisite to 
marketing and importation. See 47 CFR 15.101, 15.201, 15.305, and 
15.405. The changes proposed in this proceeding would not change any of 
the current reporting or recordkeeping requirements. Further, the 
proposed regulations adds permissible measurement techniques and 
methods of operation. The proposals would not require the modification 
of any existing products.

E. Significant Alternatives to Proposed Rules Which Minimize 
Significant Economic Impact on Small Entities and Accomplish Stated 
Objectives

    13. None.

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

    14. None.

List of Subjects in 47 CFR Part 15

    Communications equipment.

Federal Communications Commission.
Magalie Roman Salas,
Secretary.
[FR Doc. 99-18428 Filed 7-19-99; 8:45 am]
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