§ 27.64   Protection from interference.

   Wireless Communications Service (WCS) stations operating in full accordance
   with  applicable  FCC  rules  and  the  terms  and conditions of their
   authorizations are normally considered to be non-interfering. If the FCC
   determines, however, that interference which significantly interrupts or
   degrades  a radio service is being caused, it may, after notice and an
   opportunity for a hearing, require modifications to any WCS station as
   necessary to eliminate such interference.

   (a) Failure to operate as authorized. Any licensee causing interference to
   the service of other stations by failing to operate its station in full
   accordance with its authorization and applicable FCC rules shall discontinue
   all transmissions, except those necessary for the immediate safety of life
   or property, until it can bring its station into full compliance with the
   authorization and rules.

   (b) Intermodulation interference. Licensees should attempt to resolve such
   interference by technical means.

   (c)  Situations in which no protection is afforded. Except as provided
   elsewhere in this part, no protection from interference is afforded in the
   following situations:

   (1)  Interference  to  base receivers from base or fixed transmitters.
   Licensees should attempt to resolve such interference by technical means or
   operating arrangements.

   (2) Interference to mobile receivers from mobile transmitters. No protection
   is provided against mobile-to-mobile interference.

   (3) Interference to base receivers from mobile transmitters. No protection
   is provided against mobile-to-base interference.

   (4) Interference to fixed stations. Licensees should attempt to resolve such
   interference by technical means or operating arrangements.

   (5) Anomalous or infrequent propagation modes. No protection is provided
   against interference caused by tropospheric and ionospheric propagation of
   signals.

   (d) Harmful interference to SDARS operations requiring resolution. The
   following conditions will be presumed to constitute harmful interference to
   SDARS operations from WCS operations in the 2305-2320 MHz and 2345-2360 MHz
   bands and require WCS operators to work cooperatively with SDARS operators
   to  address  areas  where  such  power levels are exceeded and harmful
   interference occurs:

   (1) A WCS ground signal level greater than -44 dBm in the upper or lower A
   or B block, or -55 dBm in the C or D block, present at a location on a
   roadway, where a test demonstrates that SDARS service would be muted over a
   road distance of greater than 50 meters; or

   (2) A WCS ground signal level exceeding -44 dBm in the upper or lower A or B
   block,  or -55 dBm in the C or D block on a test drive route, which is
   mutually agreed upon by the WCS licensee and the SDARS licensee, for more
   than 1 percent of the cumulative surface road distance on that drive route,
   where  a  test  demonstrates  that SDARS service would be muted over a
   cumulative road distance of greater than 0.5 percent (incremental to any
   muting present prior to use of WCS frequencies in the area of that drive
   test).

   [ 62 FR 9658 , Mar. 3, 1997, as amended at  78 FR 9621 , Feb. 11, 2013]

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