§ 101.105   Interference protection criteria.

   (a) The interference protection criteria for fixed stations subject to
   this part are as follows:

   (1) To long-haul analog systems, employing frequency modulated radio
   and frequency division multiplexing to provide multiple voice channels,
   the allowable interference level per exposure:

   (i) Due to co-channel sideband-to-sideband interference must not exceed
   5 pwpO (Picowatts of absolute noise power psophometrically weighted
   (pwpO), appearing in an equivalent voice band channel of 300-3400 Hz);
   or

   (ii) Due to co-channel carrier-beat interference must not exceed 50
   pwpO.

   (2) To short-haul analog systems employing frequency modulated radio
   and frequency division multiplexing to provide multiple voice channels,
   the allowable interference level per exposure:

   (i) Due to co-channel sideband-to-sideband interference must not exceed
   25 pwpO except in the 952-960 MHz band interference into single link
   fixed relay and control stations must not exceed 250 pwpO per exposure;
   or

   (ii) Due to co-channel carrier-beat interference must not exceed 50
   pwpO except in the 952-960 MHz band interference into single link fixed
   relay and control stations must not exceed 1000 pwpO per exposure.

   (3) FM-TV. In analog systems employing frequency modulated radio that
   is modulated by a standard, television (visual) signal, the allowable
   interference level per exposure may not exceed the levels which would
   apply to long-haul or short-haul FM-FDM systems, as outlined in
   paragraphs (b) (1) and (2) of this section, having a 600-1200 voice
   channel capacity.

   (4) 12.2-12.7 GHz band. (i) To accommodate co-primary NGSO FSS earth
   stations in the 12.2-12.7 GHz band, the PFD of an MVDDS transmitting
   system must not exceed -135 dBW/m2 in any 4 kHz band at a reference
   point at the surface of the earth at a distance greater than 3
   kilometers from the MVDDS transmitting antenna.

   (ii) To accommodate co-primary Direct Broadcast Satellite Service earth
   stations, an MVDDS transmitting system must not exceed the EPFD levels
   specified in paragraph (a)(4)(ii)(B) of this section at any DBS
   subscriber location in accordance with the procedures listed in
   § 101.1440 of this part.

   (A) Definition of equivalent power flux density: The equivalent power
   flux density (EPFD) is the power flux density produced at a direct
   broadcast service (DBS) receive earth station, taking into account
   shielding effects and the off-axis discrimination of the receiving
   antenna assumed to be pointing at the appropriate DBS satellite(s) from
   the transmitting antenna of a multichannel video distribution and data
   service (MVDDS) transmit station. The EPFD in dBW/m2 in the reference
   bandwidth is calculated using the following formula:
   eCFR graphic er07jn04.000.gif

   View or download PDF

   Where:

   Pout = Total output power of the MVDDS transmitter (watts) into antenna

   Gm (thm,fm = Gain of the MVDDS antenna in the direction of the DBS
   earth station

   Ge (the,fe = Gain of the earth station in the direction of the MVDDS
   antenna

   I = Interference scaling factor for the earth station (1 dB for MVDDS
   transmitters employing the modulation discussed in Section 3.1.5 of the
   MITRE Report (i.e., a QPSK modulated signal passed through a
   square-root raised cosine filter). For other modulation and filtering
   schemes, the interference scaling factor can be measured using the
   procedures described in Appendix A of the MITRE Report available at
   http://www.fcc.gov/oet/info/mitrereport/mitrereport_4_01.pdf).

   Ge,  max = Maximum gain of the DBS earth station

   d = the distance between the MVDDS transmitting antenna and the DBS
   earth station (meters)

   (B) Regional equivalent power flux density levels:

   (1) -168.4 dBW/m2/4kHz in the Eastern region consisting of the District
   of Columbia and the following states: Maine, New Hampshire, Vermont,
   Massachusetts, Rhode Island, Connecticut, New York, New Jersey,
   Pennsylvania, Delaware, Maryland, Virginia, West Virginia, Kentucky,
   Tennessee, North Carolina, South Carolina, Georgia, Alabama,
   Mississippi, Louisiana, and Florida;

   (2) -169.8 dBW/m2/4kHz in the Midwestern region consisting of the
   following states: Ohio, Michigan, Indiana, Wisconsin, Illinois,
   Minnesota, Iowa, Missouri, Arkansas, South Dakota, Nebraska, Kansas,
   Oklahoma, and Texas;

   (3) -171.0 dBW/m2/4kHz in the Southwestern region consisting of the
   following states: Wyoming, Colorado, New Mexico, Utah, Arizona, Nevada,
   and California (south of 37DEG North Latitude);

   (4) -172.1 dBW/m2/4kHz in the Northwestern region consisting of the
   following states: Washington, Oregon, California (north of 37DEG North
   Latitude), Idaho, Montana, North Dakota, Alaska, and Hawaii.

   (iii) Except for public safety entities, harmful interference
   protection from MVDDS stations to incumbent point-to-point 12 GHz fixed
   stations is not required. Incumbent point-to-point private operational
   fixed 12 GHz stations, except for public safety entities, are required
   to protect MVDDS stations under the process described in § 101.103(d)
   of this part.

   (5) 71,000-76,000 MHz; 81,000-86,000 MHz. In these bands the following
   interference criteria shall apply:

   (i) For receivers employing digital modulation: based upon manufacturer
   data and following TSB 10-F or other generally acceptable good
   engineering practice, for each potential case of interference a
   threshold-to-interference ratio (T/I) shall be determined that would
   cause 1.0 dB of degradation to the static threshold of the protected
   receiver. For the range of carrier power levels (C) between the
   clear-air (unfaded) value and the fully-faded static threshold value,
   in no case shall interference cause C/I to be less than the T/I so
   determined unless it can be shown that the availability of the affected
   receiver would still be acceptable despite the interference.

   (ii) For receivers employing analog modulation: manufacturer data or
   industry criteria will specify a baseband signal-to-noise requirement
   (S/N) of the receiver that will result in acceptable signal quality for
   continuous operation. Following TSB 10-F or other generally acceptable
   good engineering practice, for each potential case of interference a
   C/I objective shall be calculated to ensure that this S/N will not be
   degraded by more than 1.0 dB. For the range of carrier power levels (C)
   between the clear-air (unfaded) value and the fully-faded threshold
   value, in no case shall interference cause the C/I to be less than the
   objective so determined unless it can be shown that the signal quality
   and availability of the affected receiver would still be acceptable
   despite the interference.

   (6) 92,000-94,000 MHz; 94,100-95,000 MHz. In these bands prior links
   shall be protected to a threshold-to-interference ratio (T/I) level of
   1.0 dB of degradation to the static threshold of the protected
   receiver. Any new link shall not decrease a previous link's
   desired-to-undesired (D/U) signal ratio below a minimum of 36 dB,
   unless the earlier link's licensee agrees to accept a lower D/U.

   (7) All stations operating under this part must protect the radio quiet
   zones as required by § 1.924 of this chapter. Stations authorized by
   competitive bidding are cautioned that they must receive the
   appropriate approvals directly from the relevant quiet zone entity
   prior to operating.

   (b) In addition to the requirements of paragraph (a) of this section
   the adjacent channel interference protection criteria to be afforded,
   regardless of system length, or type of modulation, multiplexing, or
   frequency band, must be such that the interfering signal does not
   produce more than 1.0 dB degradation of the practical threshold of the
   protected receiver. The "practical threshold" of the protected receiver
   can be based upon the definition in TSB 10, referenced in paragraph (c)
   of this section, or upon alternative generally acceptable good
   engineering standards.

   (c) Applying the criteria. (1) Guidelines for applying the interference
   protection criteria for fixed stations subject to this part are
   specified in the Telecommunications Industry Association's
   Telecommunications Systems Bulletin TSB 10, "Interference Criteria for
   Microwave Systems" (TSB 10). Other procedures that follow generally
   acceptable good engineering practices are also acceptable to the
   Commission.

   (2) If TSB 10 guidelines cannot be used, the following interference
   protection criteria may be used by calculating the ratio in dB between
   the desired (carrier signal) and the undesired (interfering) signal
   (C/I ratio) appearing at the input to the receiver under investigation
   (victim receiver). Except as provided in § 101.147 where the
   applicant's proposed facilities are of a type not included in
   paragraphs (a) and (b) of this section or where the development of the
   carrier-to-interference (C/I) ratio is not covered by generally
   acceptable procedures, or where the applicant does not wish to develop
   the carrier-to-interference ratio, the applicant must, in the absence
   of criteria or a developed C/I ratio, employ the following C/I
   protection ratios:

   (i) Co-Channel Interference. Both side band and carrier-beat,
   applicable to all bands; the existing or previously authorized system
   must be afforded a carrier to interfering signal protection ratio of at
   least 90 dB, except in the 952-960 MHz band where it must be 75dB, and
   in the 71,000-76,000 MHz and 81,000-86,000 MHz bands where the criteria
   in paragraph (a)(5) of this section applies, and in the 92,000-94,000
   MHz and 94,100-95,000 MHz bands, where the criteria in paragraph (a)(6)
   of this section applies; or

   (ii) Adjacent Channel Interference. Applicable to all bands; the
   existing or previously authorized system must be afforded a carrier to
   interfering signal protection ratio of at least 56 dB, except in the
   71,000-76,000 MHz and 81,000-86,000 MHz bands where the criteria in
   paragraph (a)(5) of this section applies, and in the 92,000-94,000 MHz
   and 94,100-95,000 MHz bands, where the criteria in paragraph (a)(6) of
   this section applies.

   (3) Applicants for frequencies listed in § 101.147(b)(1) through (4)
   must make the following showings that protection criteria have been met
   over the entire service area of existing systems. Such showings may be
   made by the applicant or may be satisfied by a statement from a
   frequency coordinator.

   (i) For site-based multiple address stations in the 928-929/952-960 MHz
   and the 932-932.5/941-941.5 MHz bands, a statement that the proposed
   system complies with the following co-channel separations from all
   existing stations and pending applications:

   Fixed-to-fixed--145 km;

   Fixed-to-mobile--113 km;

   Mobile-to-mobile--81 km

   Note to paragraph (c)(3)(i): Multiple address systems employing only
   remote stations will be treated as mobile for the purposes of
   determining the appropriate separation. For mobile operation, the
   mileage is measured from the reference point specified on the license
   application. For fixed operation on subfrequencies in accordance with
   § 101.147 the mileage also is measured from the reference point
   specified on the license application.

   (ii) In cases where the geographic separation standard in paragraph
   (c)(3)(i) of this section is not followed, an engineering analysis must
   be submitted to show the coordination of the proposed assignment with
   existing systems located closer than those standards. The engineering
   analyses will include:

   (A) Specification of the interference criteria and system parameters
   used in the interference study;

   (B) Nominal service areas of each system included in the interference
   analysis;

   (C) Modified service areas resulting from the proposed system. The
   propagation models used to establish the service boundary limits must
   be specified and any special terrain features considered in computing
   the interference impact should be described; and

   (D) A statement that all parties affected have agreed to the
   engineering analysis and will accept the calculated levels of
   interference.

   (iii) MAS EA licensees shall provide protection in accordance with
   § 101.1333.

   (4) Multiple address systems operating on subfrequencies in accordance
   with § 101.147 that propose to operate master stations at unspecified
   locations must define the operating area by a radius about a
   geographical coordinate and describe how interference to co-channel
   users will be controlled.

   (5) Multiple address frequencies in the 956.25-956.45 MHz bands may be
   assigned for use by mobile master stations on a primary basis. Multiple
   address frequencies in the 941.0-941.5 MHz bands that are licensed on a
   site-by-site basis and the 952 MHz bands may be assigned for use by
   primary mobile master stations on a case-by-case basis if the
   956.25-956.45 MHz frequencies are unavailable. Multiple address mobile
   (master and remote) operation is permitted on frequencies licensed by
   geographic area subject to the interference protection criteria set
   forth in § 101.1333, i.e., adjacent channel site-based licensees and
   co-channel operations in adjacent EAs. Mobile operation in the
   959.85-960 MHz band is not permitted.

   (6) Each application for new or modified nodal station on channels
   numbered 4A, 4B, 7, 9, and 19/20 in the 10.6 GHz band must demonstrate
   that all existing co-channel stations are at least 56 kilometers from
   the proposed nodal station site. Applicants for these channels must
   certify that all licensees and applicants for stations on the adjacent
   channels within 56 kilometers of the proposed nodal station have been
   notified of the proposed station and do not object. Alternatively, or
   if one of the affected adjacent channel interests does object, the
   applicant may show that all affected adjacent channel parties are
   provided a C/I protection ratio of 0 dB. An applicant proposing to
   operate at an AAT greater than 91 meters must reduce its EIRP in
   accordance with the following table; however, in no case may EIRP
   exceed 70 dBm on the 10.6 GHz channels:
   AAT (meters)  EIRP dBm
   Above 300         +38
   251 to 300         41
   201 to 250         43
   151 to 200         49
   101 to 150          55
   100 and below       85

   (7) Each application for new or modified nodal station on channels
   numbered 21, 22, 23, and 24 in the 10.6 GHz band must include an
   analysis of the potential for harmful interference to all other
   licensed and previously applied for co-channel and adjacent channel
   stations located within 80 kilometers of the location of the proposed
   station. The criteria contained in § 101.103(d)(2) must be used in this
   analysis. Applicants must certify that copies of this analysis have
   been served on all parties which might reasonably be expected to
   receive interference above the levels set out in § 101.103(d)(2) within
   5 days of the date the subject application is filed with the
   Commission.

   (8) If the potential interference will exceed the prescribed limits, a
   statement shall be submitted with the application for new or modified
   stations to the effect that all parties have agreed to accept the
   higher level of interference.

   (d) Effective August 1, 1985, when a fixed station that conforms to the
   technical standards of this subpart (or, in the case of the
   12,200-12,700 MHz band, for an incumbent non-MVDDS station or a direct
   broadcast satellite station) receives or will receive interference in
   excess of the levels specified in this section as a result of an
   existing licensee's use of non-conforming equipment authorized between
   July 20, 1961 and July 1, 1976, and the interference would not result
   if the interfering station's equipment complied with the current
   technical standards, the licensee of the non-conforming station must
   take whatever steps are necessary to correct the situation up to the
   point of installing equipment which fully conforms to the technical
   standards of this subpart. In such cases, if the engineering analysis
   demonstrates that:

   (1) The conforming station would receive interference from a
   non-conforming station in excess of the levels specified in this
   section; and

   (2) The interference would be eliminated if the non-conforming
   equipment were replaced with equipment which complies with the
   standards of this subpart, the licensee (or prospective licensee) of
   the station which would receive interference must provide written
   notice of the potential interference to both the non-conforming
   licensee and the Commission's office in Gettysburg, PA. The
   non-conforming licensee must make all required equipment changes within
   180 days from the date of official Commission notice informing the
   licensee that it must upgrade its equipment, unless an alternative
   solution has been agreed to by all parties involved in the interference
   situation. If a non-conforming licensee fails to make all required
   changes within the specified period of time, the Commission may require
   the licensee to suspend operation until the changes are completed.

   (e) Interference dispute resolution procedures. Should a licensee
   licensed under this part receive harmful interference from another
   licensee licensed under this chapter, the parties involved shall comply
   with the dispute resolution procedures set forth herein:

   (1) The licensee experiencing the harmful interference shall notify the
   licensee believed to be causing the harmful interference and shall
   supply information describing its problem and supporting its claim;

   (2) Upon receipt of the harmful interference notice, the licensee
   alleged to be causing the harmful interference shall respond
   immediately and make every reasonable effort to identify and resolve
   the conflict; and

   (3) Licensees are encouraged to resolve the harmful interference prior
   to contacting the Commission.

   [ 61 FR 26677 , May 28, 1996, as amended at  63 FR 68983 , Dec. 14, 1998;
    65 FR 17449 , Apr. 3, 2000;  65 FR 38329 , June 20, 2000;  65 FR 59358 ,
   Oct. 5, 2000;  66 FR 35110 , July 3, 2001;  67 FR 43038 , June 28, 2002;  69 FR 31746 , June 7, 2004;  70 FR 29996 , May 25, 2005]

   return arrow Back to Top