[Federal Register Volume 62, Number 92 (Tuesday, May 13, 1997)]
[Rules and Regulations]
[Pages 26239-26245]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-11584]


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FEDERAL COMMUNICATIONS COMMISSION

47 CFR Parts 2 and 15

[ET Docket No. 96-8; FCC 97-114]


Spread Spectrum Transmitters

AGENCY: Federal Communications Commission.

ACTION: Final rule.

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SUMMARY: By this Report and Order, the Commission amends its 
regulations regarding the unlicensed operation of spread spectrum 
systems in the 902-928 MHz (``915 MHz''), 2400-2483.5 MHz (``2450 
MHz''), and 5725-5850 MHz (``5800 MHz'') bands, as proposed in the 
Notice of Proposed Rule Making (``NPRM'') in this proceeding. These 
amendments permit the use of high gain directional antennas for systems 
operating as fixed, point-to-point stations in the 2450 MHz and 5800 
MHz bands. They also reduce the number of hopping channels for 
frequency hopping systems operating in the 915 MHz band. In addition, 
these amendments clarify existing regulations, codify existing policies 
into the rules, and update the definitions. These amendments will 
facilitate the growth of spread spectrum systems by enabling and 
encouraging practical applications for these systems.

DATES: Effective June 12, 1997.

ADDRESSES: Federal Communications Commission, 1919 M Street, N.W., 
Washington, D.C. 20554.

FOR FURTHER INFORMATION CONTACT: John A. Reed, Office of Engineering 
and Technology, (202) 418-2455.

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Report 
and Order in ET Docket No. 96-8, FCC 97-114, adopted April 3, 1997, and 
released April 10, 1997. The complete text of this Report and Order is 
available for inspection and copying during normal business hours in 
the FCC Reference Center (Room 239), 1919 M Street, NW., Washington, 
DC, and also may be purchased from the Commission's copy contractor, 
International Transcription Services, Inc., (202) 857-3800, 2100 M 
Street, NW, Suite 140, Washington, D.C. 20037.

Summary of the Report and Order

    1. In the Report and Order (``Order''), the Commission amended 
Parts 2 and 15 of its regulations regarding unlicensed spread spectrum 
transmission systems operating in the 915 MHz, 2450 MHz and 5800 MHz 
bands. Spread spectrum systems use special modulation techniques that 
spread the energy of the signal being transmitted over a very wide 
bandwidth. This spreading reduces the power density of the signal at 
any frequency within the transmitted bandwidth, thereby reducing the 
probability of causing interference to other signals occupying the same 
spectrum. The reversal of the signal spreading process in the receiver 
enables the suppression of strong undesired signals.
    2. The Order eliminates the limit on directional gain antennas for 
spread spectrum transmitters operating in the 2450 MHz and the 5800 MHz 
bands. The operation of these systems is limited to fixed, point-to-
point systems. While transmitters in the 5800 MHz band are not required 
to reduce output power when the directional antenna

[[Page 26240]]

gain is increased, the maximum permitted output power of spread 
spectrum transmitters in the 2450 MHz band is decreased by 1 dB for 
every 3 dB that the directional antenna gain exceeds 6 dBi. This 
decrease in the maximum transmitter output power is necessary to reduce 
the potential for harmful interference to mobile stations operating in 
the 2450 MHz band, especially mobile licensees in the Public Safety 
Radio Services under Part 90 of the rules and other Part 15 devices. 
The waivers previously issued to six companies to permit the 
manufacture of systems at 2450 MHz and 5800 MHz employing unlimited 
antenna gain without a reduction in transmitter output power are no 
longer in effect upon 30 days from the publication of these final rules 
in the Federal Register. Any system manufactured after that date must 
comply with the regulations adopted herein.
    3. The increase in directional antenna gain will permit users of 
spread spectrum systems to establish radio links without the delays and 
costs associated with formal frequency coordination and licensing. Such 
uses may include backbone connections to the new unlicensed NII system; 
intelligent transportation system communications links; high speed 
Internet connections for schools, hospitals, and government offices; 
energy utility applications; PCS and cellular backbone connections; and 
T-1 common carrier links in rural areas. However, the operators of 
these systems are reminded that the operation of Part 15 devices is 
subject to the conditions that any received interference must be 
accepted and that harmful interference may not be caused to other radio 
services. Thus, the Commission strongly recommends that operators of 
systems that provide critical communication services should exercise 
due caution to determine if there are any nearby radio services that 
could be affected by their communications.
    4. In the Order, the Commission also reduces the minimum number of 
non-contiguous channels that must be employed by a frequency hopping 
spread spectrum system in the 915 MHz band from 50 channels to 25 
channels. This reduction in the number of hopping channels will enable 
frequency hopping spread spectrum systems to avoid operations on 
frequencies used by wideband, multilateration LMS systems operating 
under Part 90 of the rules, thereby reducing mutual interference 
problems. Frequency hopping spread spectrum systems that employ less 
than 50 hopping channels must employ channel bandwidths of at least 250 
kHz; shall not exceed an average time of occupancy on any hopping 
frequency of 0.4 seconds in any 10 second period; and shall operate 
with a maximum peak transmitter output power of 250 mW with a 
directional antenna gain of 6 dBi. Higher antenna gain is permitted 
only with a corresponding decrease in transmitter output power.
    5. In the Order, the Commission made several amendments to the 
rules to clarify existing regulations, codify existing policies into 
the rules, and update the definitions. These amendments to the rules 
are summarized below:
    --The spectral power density limit for direct sequence systems is 
modified to indicate that the standard applies to the peak spectral 
power density, and the measurement procedure employed for measuring 
spectral power density where the spectrum line spacing can not be 
resolved is corrected;
    --The definition of a direct sequence system is modified, as 
proposed in the NPRM;
    --The definition of a pseudorandom sequence and a frequency hopping 
system is modified, as proposed in the NPRM;
    --The rules are clarified to permit short duration transmissions 
under the provisions for frequency hopping systems provided the systems 
are capable of complying with all of the spread spectrum standards, 
including the definition of a frequency hopping systems and the 
eventual distribution of the transmissions over the minimum number of 
hopping channels;
    --An alternative method of measuring the processing gain of a 
direct sequence system, based on receiver jamming margin, is 
incorporated into the rules;
    --The limits on unwanted emissions are simplified, as proposed in 
the NPRM;
    --The existing policy permitting the coordination of a frequency 
hopping system when the system incorporates intelligence that permits 
it to recognize other users within the spectrum band so that it 
individually and independently chooses and adapts its hopping sequence 
to avoid hopping on occupied channels is codified into the rules;
    --The prohibition against the marketing and use of external radio 
frequency power amplifiers that are not certified as part of the system 
and the prohibition against the marketing and use of antenna/
transmitter combinations that are not certified as a system is 
clarified in the rules;
    --The applicability of the RF guidelines for human exposure, as 
specified in Section 1.1307 of the rules, to Part 15 devices is noted; 
and
    --The prohibition against cross-border operation into Mexico or 
Canada and the applicability of the non-interference rules to Canadian 
or Mexican radio operations are noted.

Final Regulatory Flexibility Analysis

    6. As required by Section 603 of the Regulatory Flexibility Act, 5 
U.S.C. 603 (RFA), Initial Regulatory Flexibility Analysis (IRFA) was 
incorporated in the Notice of Proposed Rule Making (``NPRM'') in ET 
Docket No. 96-8.1 The Commission sought written public 
comments on the proposals in the NPRM including the IRFA. The 
Commission's Regulatory Flexibility Analysis (FRFA) in this Report and 
Order conforms to the RFA, as amended by the Contract with America 
Advancement Act of 1996 (CWAAA), Public Law 104-121, 110 Stat. 847 
(1996).2
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    \1\ Amendment of Parts 2 and 15 of the Commission's Rules 
Regarding Spectrum Transmitters, 11 FCC Rcd 3068 (1996), 61 FR 
15206, April 5, 1996.
    \2\ Subtitle II of the CWAAA is ``The Small Business Regulatory 
Enforcement Fairness Act of 1996'' (SBREFA), codified at 5 U.S.C. 
601 et seq.
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    7. Need for and Objective of the Rule. The objective is to amend 
Parts 2 and 15 of the rules regarding the operation of spread spectrum 
transmission systems in the 902-928 MHz, 2400-2483.5 MHz and 5725-5850 
MHz bands. The Commission is also adopting 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 to the rules will facilitate the growth of 
the spread spectrum industry by enabling and encouraging practical 
applications for these products. The new rules will expand the ability 
of equipment manufacturers to develop spread spectrum systems for 
unlicensed use that provide users with the flexibility to establish 
radio links without the delays and costs associated with formal 
frequency coordination and licensing. Such uses may include intelligent 
transportation system communications links; high speed Internet 
connections for schools, hospitals, and government offices; energy 
utility applications; PCS and cellular backbone connections; and T-1 
common carrier links in rural areas. The new rules will also permit 
frequency hopping spread spectrum systems and wideband, multilateration 
Location Monitoring Service (LMS) systems to operate within the same 
frequency band with decreased potential for mutual interference 
problems.

[[Page 26241]]

    8. Summary of Significant Issues Raised by the Public Comments in 
Response to the Initial Regulatory Flexibility Analysis. Only one 
commenter, Adtran submitted comments that were specifically in response 
to the IRFA. It agrees with the Commission's assessment that the 
changes made in the ``Order'' will have no negative impact on small 
entities. In general, commenters were supportive of the Commission's 
proposed changes to the rule. The Commission also received numerous 
suggestions for improving or modifying the rules. In response to a 
Petition for Rule Making filed by WMC, the Commission is eliminating 
the limit on directional gain antennas for spread spectrum transmitters 
operating in the 2450 MHz and 5800 MHz bands. For spread spectrum 
systems operating in the 2450 MHz band, the Commission is implementing 
its proposal to require that the output power for the transmitter be 
reduced by 1 dB for every 3 dB that the directional gain exceeds 6 dBi. 
In addition, in response to a Petition for Rule Making filed by 
SpectraLink, the Commission is reducing, from 50 to 25, the minimum 
number of channels required for frequency hopping spread spectrum 
systems operating in the 915 MHz band.
    9. Description and Estimate of the Number of Small Entities Subject 
to Which the Rules Apply. The RFA generally defines the term ``small 
business'' as having the same meaning as the term ``small business 
concern'' under the Small Business Act, 15 U.S.C. 632. Based on that 
statutory provision, we will consider a small business concern one 
which: (1) Is independently owned and operated; (2) is not dominant in 
its field of operation; and (3) satisfies any additional criteria 
established by the Small Business Administration (SBA). The RFA SBREFA 
provisions also apply to nonprofit organizations and to governmental 
organizations. Since the Regulatory Flexibility Act amendments were not 
in effect until the record in this proceeding was closed, the 
Commission was unable to request information regarding the number of 
small businesses that manufacture spread spectrum transmitters and is 
unable at this time to determine the number of small businesses that 
would be affected by this action. However, the Commission believes that 
the amendments being adopted in this proceeding clarify permissible 
methods of operation. With the exception of limits on directional 
antenna gain versus transmitter output power for systems in the 2450 
MHz band, these amendments should not impact any existing equipment 
designs. The only parties that would be impacted by the requirement to 
reduce transmitter output power when high antenna gains are employed 
are WMC, Cylink, ACS, MDS, Larus, and Wi-LAN Inc. These companies are 
currently producing this equipment under the conditions of a temporary 
waiver that permits them to manufacture fixed, point-to-point spread 
spectrum systems in the 2450 MHz band without a limit on directional 
antenna gain. All of these companies were notified at the time the 
waivers were granted that the waivers would expire upon the date of 
final action in this proceeding.
    10. The rules adopted in this Order will apply to any entities 
manufacturing equipment for unlicensed Part 15 spread spectrum 
transmitters. The Commission has not developed a definition of small 
entities applicable to manufacturers of spread spectrum transmitters. 
Therefore, the applicable definition of small entity is the definition 
under the Small Business Administration (``SBA'') rules applicable to 
manufacturers of ``Radio and Television Broadcasting and Communications 
Equipment''. According to the SBA's regulations, radio frequency 
manufacturers must have 750 or fewer employees in order to qualify as a 
small business.3 Census Bureau data indicates that there are 
858 companies in the United States that manufacture radio and 
television broadcasting and communications equipment, and that 778 of 
these firms have fewer than 750 employees and would be classified as 
small entities.4
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    \3\ See 13 CFR 121.201, Standard Industrial Classification (SIC) 
Code 3663.
    \4\ See U.S. Department of Commerce, 1992 Census of 
Transportation, Communications and Utilities (issued May 1995), SIC 
category 3663.
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    11. Description of Projected 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, except for those currently 
operating under limited waivers that expire upon adoption of this 
Order. These requirements include obtaining a grant of certification 
for the transmitter and meeting the emission limits specified in the 
rules.
    12. Skills of an application examiner, radio technician or engineer 
will be needed to meet the requirements. In many cases the studies can 
be done by a radio technician or engineer. Certification applications 
are usually done by applications examiners. It is the responsibility of 
the manufacturer of the device to determine whether the device will 
comply with the RF radiation limits. This study can be done by 
calculation or measurement, depending upon the situation.
    13. Significant Alternatives and Steps Taken by Agency to Minimize 
Significant Economic Impact on a Substantial Number of Small Entities 
Consistent with Stated Objectives. In response to concerns raised in 
comments filed in response to the NPRM, the Commission made several 
minor clarifying amendments to its proposals. However, there was only 
one issue raised in the comments that could have had a significant 
economic impact on the manufacturers of spread spectrum systems. In the 
NPRM, the Commission proposed to require that the 3 dB beamwidths of 
the high gain directional antennas employed with spread spectrum 
transmitters differ by no more than a factor of two between the 
vertical and horizontal planes.5 Supporting comments were 
received from Adtran and Digital Wireless; however, Cushcraft, Cylink, 
the Part 15 Coalition and WMC believe that the requirement is an 
unnecessary regulation. Cushcraft believes that the majority of 
antennas already meet this criterion. Cylink states that this proposal 
may prevent applications that require a different antenna design, such 
as communications to off-shore platforms. The Commission agrees with 
the latter commenters that this portion of its proposal is unnecessary.
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    \5\ See NPRM at para. 17.
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    14. Commission's Outreach Efforts to Learn of and Respond to the 
Views of Small Entities pursuant to SBREFA 5 U.S.C. 609. During the 
course of this proceeding Office of Engineering and Technology staff 
members have had numerous ex parte meetings with representatives from 
Metricom, Inc., Cylink Corporation, Mulcay Consulting Association, and 
Digital Wireless Corporation.
    15. Report to Congress. The Commission shall send a copy of this 
Final Regulatory Flexibility Analysis, along with this Report and 
Order, in a report to Congress pursuant to the Small Business 
Regulatory Enforcement Fairness Act of 1996, 5 U.S.C. 801(a)(1)(A). A 
copy of this FRFA will

[[Page 26242]]

also be published in the Federal Register.

List of Subjects

47 CFR Part 2

    Communications equipment, Radio.

47 CFR Part 15

    Communications equipment, Radio, Reporting and recordkeeping 
requirements.

Federal Communications Commission
William F. Caton,
Acting Secretary.

Rule Changes

    Title 47 of the Code of Federal Regulations, Parts 2 and 15, are 
amended as follows:

PART 2--FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL 
RULES AND REGULATIONS

    1. The authority citation for Part 2 continues to read as follows:

    Authority: Sec. 4, 302, 303, and 307 of the Communications Act 
of 1934, as amended, 47 U.S.C. Sections 154, 302, 303, and 307, 
unless otherwise noted.

    2. Section 2.1, paragraph (c), is amended by removing the 
definition for ``Pseudorandom sequence'', by revising the definition 
for ``Direct Sequence Systems'', and by revising the definition for 
``Frequency Hopping Systems'' and placing it in alphabetical order to 
read as follows:


Sec. 2.1  Terms and definitions.

* * * * *
    (c) * * *
* * * * *
    Direct Sequence Systems. A spread spectrum system in which the 
carrier has been modulated by a high speed spreading code and an 
information data stream. The high speed code sequence dominates the 
``modulating function'' and is the direct cause of the wide spreading 
of the transmitted signal.
* * * * *
    Frequency Hopping Systems. A spread spectrum system in which the 
carrier is modulated with the coded information in a conventional 
manner causing a conventional spreading of the RF energy about the 
frequency carrier. The frequency of the carrier is not fixed but 
changes at fixed intervals under the direction of a coded sequence. The 
wide RF bandwidth needed by such a system is not required by spreading 
of the RF energy about the carrier but rather to accommodate the range 
of frequencies to which the carrier frequency can hop. The test of a 
frequency hopping system is that the near term distribution of hops 
appears random, the long term distribution appears evenly distributed 
over the hop set, and sequential hops are randomly distributed in both 
direction and magnitude of change in the hop set.
* * * * *

PART 15--RADIO FREQUENCY DEVICES

    1. The authority citation for Part 15 continues to read as follows:

    Authority: 47 U.S.C. 154, 302, 303, 304, 307 and 544A.

    2. Section 15.3 is amended by adding a new paragraph (cc), to read 
as follows:


Sec. 15.3  Definitions.

* * * * *
    (cc) External radio frequency power amplifier. A device which is 
not an integral part of an intentional radiator as manufactured and 
which, when used in conjunction with an intentional radiator as a 
signal source, is capable of amplifying that signal.
    3. A new Sec. 15.204 is added, to read as follows:


Sec. 15.204  External radio frequency power amplifiers and antenna 
modifications.

    (a) Except as otherwise described in paragraph (b) of this section, 
no person shall use, manufacture, sell or lease, offer for sale or 
lease (including advertising for sale or lease), or import, ship, or 
distribute for the purpose of selling or leasing, any external radio 
frequency power amplifier or amplifier kit intended for use with a Part 
15 intentional radiator.
    (b) A transmission system consisting of an intentional radiator, an 
external radio frequency power amplifier, and an antenna, may be 
authorized, marketed and used under this part. However, when a 
transmission system is authorized as a system, it must always be 
marketed as a complete system and must always be used in the 
configuration in which it was authorized. An external radio frequency 
power amplifier shall be marketed only in the system configuration with 
which the amplifier is authorized and shall not be marketed as a 
separate product.
    (c) Only the antenna with which an intentional radiator is 
authorized may be used with the intentional radiator.
    4. Section 15.247 is amended by revising paragraphs (a)(1)(i), (b), 
(c), (d), and (e), and by adding new paragraphs (g) and (h) before the 
note at the end of the section, to read as follows:


Sec. 15.247  Operation within the bands 902-928 MHz, 2400-2483.5 MHz, 
and 5725-5850 MHz.

    (a) * * *
    (1) * * *
    (i) For frequency hopping systems operating in the 902-928 MHz 
band: if the 20 dB bandwidth of the hopping channel is less than 250 
kHz, the system shall use at least 50 hopping frequencies and the 
average time of occupancy on any frequency shall not be greater than 
0.4 seconds within a 20 second period; if the 20 dB bandwidth of the 
hopping channel is 250 kHz or greater, the system shall use at least 25 
hopping frequencies and the average time of occupancy on any frequency 
shall not be greater than 0.4 seconds within a 10 second period. The 
maximum allowed 20 dB bandwidth of the hopping channel is 500 kHz.
* * * * *
    (b) The maximum peak output power of the intentional radiator shall 
not exceed the following:
    (1) For frequency hopping systems operating in the 2400-2483.5 MHz 
or 5725-5850 MHz band and for all direct sequence systems: 1 watt.
    (2) For frequency hopping systems operating in the 902-928 MHz 
band: 1 watt for systems employing at least 50 hopping channels; and, 
0.25 watts for systems employing less than 50 hopping channels, but at 
least 25 hopping channels, as permitted under paragraph (a)(1)(i) of 
this section.
    (3) Except as shown in paragraphs (b)(3) (i), (ii) and (iii) of 
this section, if transmitting antennas of directional gain greater than 
6 dBi are used the peak output power from the intentional radiator 
shall be reduced below the stated values in paragraphs (b)(1) or (b)(2) 
of this section, as appropriate, by the amount in dB that the 
directional gain of the antenna exceeds 6 dBi.
    (i) Systems operating in the 2400-2483.5 MHz band that are used 
exclusively for fixed, point-to-point operations may employ 
transmitting antennas with directional gain greater than 6 dBi provided 
the maximum peak output power of the intentional radiator is reduced by 
1 dB for every 3 dB that the directional gain of the antenna exceeds 6 
dBi.
    (ii) Systems operating in the 5725-5850 MHz band that are used 
exclusively for fixed, point-to-point operations may employ 
transmitting antennas with directional gain greater than 6 dBi without 
any corresponding reduction in transmitter peak output power.
    (iii) Fixed, point-to-point operation, as used in paragraphs 
(b)(3)(i) and (b)(3)(ii) of this section, excludes the use of point-to-
multipoint systems, omnidirectional applications, and multiple co-
located intentional radiators

[[Page 26243]]

transmitting the same information. The operator of the spread spectrum 
intentional radiator or, if the equipment is professionally installed, 
the installer is responsible for ensuring that the system is used 
exclusively for fixed, point-to-point operations. The instruction 
manual furnished with the intentional radiator shall contain language 
in the installation instructions informing the operator and the 
installer of this responsibility.
    (4) Systems operating under the provisions of this section shall be 
operated in a manner that ensures that the public is not exposed to 
radio frequency energy levels in excess of the Commission's guidelines. 
See Sec. 1.1307(b)(1) of this chapter.
    (c) In any 100 kHz bandwidth outside the frequency band in which 
the spread spectrum intentional radiator is operating, the radio 
frequency power that is produced by the intentional radiator shall be 
at least 20 dB below that in the 100 kHz bandwidth within the band that 
contains the highest level of the desired power, based on either an RF 
conducted or a radiated measurement. Attenuation below the general 
limits specified in Sec. 15.209(a) is not required. In addition, 
radiated emissions which fall in the restricted bands, as defined in 
Sec. 15.205(a), must also comply with the radiated emission limits 
specified in Sec. 15.209(a) (see Sec. 15.205(c)).
    (d) For direct sequence systems, the peak power spectral density 
conducted from the intentional radiator to the antenna shall not be 
greater than 8 dBm in any 3 kHz band during any time interval of 
continuous transmission.
    (e) The processing gain of a direct sequence system shall be at 
least 10 dB. The processing gain represents the improvement to the 
received signal-to-noise ratio, after filtering to the information 
bandwidth, from the spreading/despreading function. The processing gain 
may be determined using one of the following methods:
    (1) As measured at the demodulated output of the receiver: 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.
    (2) As measured using the CW jamming margin method: a signal 
generator is stepped in 50 kHz increments across the passband of the 
system, recording at each point the generator level required to produce 
the recommended Bit Error Rate (BER). This level is the jammer level. 
The output power of the intentional radiator is measured at the same 
point. The jammer to signal ratio (J/S) is then calculated, discarding 
the worst 20% of the J/S data points. The lowest remaining J/S ratio is 
used to calculate the processing gain, as follows: Gp = (S/N) o + Mj + 
Lsys, where Gp = processing gain of the system, (S/N) o = signal to 
noise ratio required for the chosen BER, Mj = J/S ratio, and Lsys = 
system losses. Note that total losses in a system, including 
intentional radiator and receiver, should be assumed to be no more than 
2 dB.
* * * * *
    (g) Frequency hopping spread spectrum systems are not required to 
employ all available hopping channels during each transmission. 
However, the system, consisting of both the transmitter and the 
receiver, must be designed to comply with all of the regulations in 
this section should the transmitter be presented with a continuous data 
(or information) stream. In addition, a system employing short 
transmission bursts must comply with the definition of a frequency 
hopping system and must distribute its transmissions over the minimum 
number of hopping channels specified in this section.
    (h) The incorporation of intelligence within a frequency hopping 
spread spectrum system that permits the system to recognize other users 
within the spectrum band so that it individually and independently 
chooses and adapts its hopsets to avoid hopping on occupied channels is 
permitted. The coordination of frequency hopping systems in any other 
manner for the express purpose of avoiding the simultaneous occupancy 
of individual hopping frequencies by multiple transmitters is not 
permitted.
* * * * *
    Note: The following appendix will not appear in the Code of 
Federal Regulations.

Appendix--Measurement Procedure for Spread Spectrum Transmitters

Federal Communications Commission
Equipment Authorization Division, 7435 Oakland Mills Road, Columbia, 
MD 21046, Telephone: (301) 725-1585, Facsimile: (301) 344-2050

Guidance on Measurements for Direct Sequence Spread Spectrum Systems

    Part 15 of the FCC Rules provides for operation of direct 
sequence spread spectrum transmitters. Examples of devices that 
operate under these rules include radio local area networks, 
cordless telephones, wireless cash registers, and wireless inventory 
tracking systems.
    The Commission frequently receives requests for guidance as to 
how to perform measurements to demonstrate compliance with the 
technical standards for such systems. No formal measurement 
procedure has been established for determining compliance with the 
technical standards. Such tests are to be performed following the 
general guidance in Section 15.31 of the FCC Rules and using good 
engineering practice. The following provides information on the 
measurement techniques the Commission has accepted in the past for 
equipment authorization purposes. Alternative techniques may be 
acceptable upon consultation and approval by the Commission staff. 
The information is organized according to the pertinent FCC rule 
sections.
    Section 15.31(m): This rule specifies the number of operating 
frequencies to be examined for tunable equipment.
    Section 15.207: Power line conducted emissions. If the unit is 
AC powered, an AC power line conducted test is also required per 
this rule.
    Section 15.247(a)(2): Bandwidth. Make the measurement with the 
spectrum analyzer's resolution bandwidth (RBW) = 100 kHz. In order 
to make an accurate measurement, set the span >> RBW.
    Section 15.247(b): Power output. This is an RF conducted test. 
Use a direct connection between the antenna port of the transmitter 
and the spectrum analyzer, through suitable attenuation. Set the RBW 
> 6 dB bandwidth of the emission or use a peak power meter.
    Section 15.247(c): Spurious emissions. The following tests are 
required :
    (1) RF antenna conducted test: Set RBW = 100 kHz, Video 
bandwidth (VBW) > RBW, scan up through 10th harmonic. All harmonics/
spurs must be at least 20 dB down from the highest emission level 
within the authorized band as measured with a 100 kHz RBW.
    (2) Radiated emission test: Applies to harmonics/spurs that fall 
in the restricted bands listed in Section 15.205. The maximum 
permitted average field strength is listed in Section 15.209. A pre-
amp (and possibly a high-pass filter) is necessary for this 
measurement. For measurements above 1 GHz, set RBW = 1 MHz, VBW = 10 
Hz, Sweep: Auto. If the emission is pulsed, modify the unit for 
continuous operation, use the settings shown above, then correct the 
reading by subtracting the peak-average correction factor, derived 
from the appropriate duty cycle calculation. See Section 15.35(b) 
and (c).
    Section 15.247(d): Power spectral density. Locate and zoom in on 
emission peak(s) within the passband. Set RBW = 3 kHz, VBW > RBW, 
sweep = (SPAN/3 kHz) e.g., for a span of 1.5 MHz, the sweep should 
be 1.5  x  106  3  x  103= 500 
seconds. The peak level measured must be no greater than +8 dBm. If 
external attenuation is used, don't forget to add this value to the 
reading. Use the following guidelines for modifying the power 
spectral density measurement procedure when necessary.
     For devices with spectrum line spacing greater than 3 
kHz no change is required.
     For devices with spectrum line spacing equal to or less 
than 3 kHz, the resolution bandwidth must be reduced below 3 kHz 
until the individual lines in the spectrum are resolved. The 
measurement data must then be normalized to 3 kHz by summing the 
power of all the individual spectral lines

[[Page 26244]]

within a 3 kHz band (in linear power units) to determine compliance.
     If the spectrum line spacing cannot be resolved on the 
available spectrum analyzer, the noise density function on most 
modern conventional spectrum analyzers will directly measure the 
noise power density normalized to a 1 Hz noise power bandwidth. Add 
34.8 dB for correction to 3 kHz.
     Should all the above fail or any controversy develop 
regarding accuracy of measurement, the Laboratory will use the HP 
89440A Vector Signal Analyzer for final measurement unless a clear 
showing can be made for a further alternate.
    Section 15.247(e): Processing Gain. The Processing Gain may be 
measured using the CW jamming margin method. Figure 1 shows the test 
configuration. The test consists of stepping a signal generator in 
50 kHz increments across the passband of the system. At each point, 
the generator level required to produce the recommended Bit Error 
Rate (BER) is recorded. This level is the jammer level. The output 
power of the transmitting unit is measured at the same point. The 
Jammer to Signal (J/S) ratio is then calculated. Discard the worst 
20% of the J/S data points. The lowest remaining J/S ratio is used 
when calculating the Processing Gain.
    In a practical system, there are always implementation losses 
which degrade the performance below that of an optimal theoretical 
system of the same type. Losses occur due to non-optimal filtering, 
lack of equalization, LO phase noise, ``corner cutting in digital 
processing'', etc. Total losses in a system, including transmitter 
and receiver, should be assumed to be no more than 2 dB.
    The signal to noise ratio for an ideal non-coherent receiver is 
calculated from:

(1) Pe = \1/2\e(--\1/2\(S/N)o)

where :
    Pe = probability of error (BER)
    (S/N)o = the required signal to noise ratio at the receiver 
output for a given received signal quality

    This is an example. You should use the equation (or curve) 
dictated by your demodulation scheme.
    Ref.: Viterbi, A. J. Principles of Coherent Communications, (New 
York: McGraw-Hill 1966), Pg. 207 Using equation (1) shown above, 
calculate the signal to noise ratio required for your chosen BER. 
This value and the measured J/S ratio are used in the following 
equation to calculate the Processing Gain (Gp) of the system.

    Gp=(S/N)o+Mj+Lsys

where:
    (S/N)o = Signal to noise ratio
    Mj = J/S ratio
    Lsys = System losses.

    Ref.: Dixon, R., Spread Spectrum Systems (New York: Wiley, 
1984), Chapter 1.

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Alternative Test Procedures

    If antenna conducted tests cannot be performed on this device, 
radiated tests to show compliance with the various conducted 
requirements of Section 15.247 are acceptable. As stated previously, 
a pre-amp must be used in making the following measurements.
    (1) Calculate the transmitter's peak power using the following 
equation: 
[GRAPHIC] [TIFF OMITTED] TR13MY97.002

Where:

[[Page 26245]]

    E is the measured maximum field strength in V/m utilizing the 
widest available RBW.
    G is the numeric gain of the transmitting antenna over an 
isotropic radiator.
    d is the distance in meters from which the field strength was 
measured.
    P is the power in watts for which you are solving: 
    [GRAPHIC] [TIFF OMITTED] TR13MY97.003
    
    (2) Measure the power spectral density as follows:
    A. Tune the analyzer to the highest point of the maximized 
fundamental emission. Reset the analyzer to a RBW = 3 kHz, VBW > 
RBW, span = 300 kHz, sweep = 100 sec.
    B. From the peak level obtained in (A), derive the field 
strength, E, by applying the appropriate antenna factor, cable loss, 
pre-amp gain, etc. Using the equation listed in (1), calculate a 
power level for comparison to the +8 dBm limit.

[FR Doc. 97-11584 Filed 5-12-97; 8:45 am]
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