§ 95.2559   MedRadio channel access requirements.

   To reduce interference and make the most effective use of the MedRadio
   frequency bands, MedRadio transmitter types must be designed to operate
   in accordance with the rules in this section.

   (a) Frequency monitoring in the 401-406 MHz band. Except as provided in
   paragraph (b) of this section, all MedRadio programmer/control
   transmitters operating in the 401-406 MHz band must operate under the
   control of a monitoring system that incorporates a mechanism for
   monitoring the channel or channels that the MedRadio system devices
   intend to occupy. The monitoring system antenna shall be the antenna
   normally used by the programmer/control transmitter for a MedRadio
   communications session. Before the monitoring system of a
   programmer/control transmitter initiates a MedRadio communications
   session, the following access criteria must be met:

   (1) The monitoring system bandwidth, measured at its 20 dB down points,
   must be equal to or greater than the MedRadio emission bandwidth of the
   intended transmission.

   (2) Within 5 seconds prior to initiating a MedRadio communications
   session, circuitry associated with a MedRadio programmer/control
   transmitter must monitor the channel or channels the system devices
   intend to occupy for a minimum of 10 milliseconds per channel.

   (3) The monitoring threshold power level, PMT, in dBm, is calculated
   using the following formula.

   PMT = 10 log B−150 (dBm/Hz) + G

   Where:

   (i) B is the MedRadio emission bandwidth in Hertz of the MedRadio
   communications session transmitter having the widest emission; and,

   (ii) G is the MedRadio programmer/control transmitter monitoring system
   antenna gain, in decibels, relative to the gain of an isotropic antenna
   (dBi).

   (4) For the purposes of showing compliance with the above provisions,
   the above calculated threshold power level must be increased or
   decreased by an amount equal to the monitoring system antenna gain
   above or below the gain of an isotropic antenna, respectively.

   (5) If no signal above the monitoring threshold power level is detected
   in a MedRadio channel, the MedRadio programmer/control transmitter may
   initiate on that channel a MedRadio communications session involving
   transmissions to and from a medical implant or medical body-worn
   device. The MedRadio communications session may continue as long as any
   silent period between consecutive data transmission bursts does not
   exceed 5 seconds. If no channel meeting the requirements in paragraphs
   (a)(3) and (4) of this section is available, MedRadio transmitters that
   are capable of operating on multiple channels may transmit on the
   alternate channel accessible by the device with the lowest monitored
   ambient power level.

   (6) When a channel is selected prior to a MedRadio communications
   session, it is permissible to select an alternate authorized channel
   for use if communications are interrupted, provided that the alternate
   channel selected is the next best choice using the above criteria. The
   alternate channel may be accessed in the event a communications session
   is interrupted by interference. The following criteria must be met:

   (i) Before transmitting on the alternate channel, the channel must be
   monitored for a period of at least 10 milliseconds.

   (ii) The detected power level during this 10 millisecond or greater
   monitoring period must be no higher than 6 dB above the power level
   detected when the channel was chosen as the alternate channel.

   (iii) In the event that this alternate channel provision is not used by
   the MedRadio system, or if the criteria in paragraphs (a)(6)(i) and
   (ii) of this section are not met, any alternate authorized channel must
   be selected using the access criteria specified in paragraphs (a)(1)
   through (5) of this section.

   (7) Except as provided in paragraph (b) of this section, MedRadio
   transmitters that operate on a single channel and thus do not have the
   capability of operating on alternate channels may not transmit unless
   no signal on the single channel of operation exceeds the monitoring
   threshold power level.

   (b) Exceptions to frequency monitoring in the 401-406 MHz band.
   MedRadio devices or communications sessions that meet any one of the
   following criteria are not required to be operated in accordance with
   the access rules set forth in paragraph (a) of this section:

   (1) MedRadio communications sessions that are initiated by a medical
   implant event.

   (2) MedRadio devices operating in either the 401-401.85 MHz or 405-406
   MHz bands, provided that the transmit power is not greater than 250
   nanowatts EIRP and the duty cycle for such transmissions does not
   exceed 0.1%, based on the total transmission time during a one-hour
   interval, and a maximum of 100 transmissions per hour.

   (3) MedRadio devices operating in the 401.85-402 MHz band, provided
   that the transmit power is not greater than 25 microwatts EIRP and the
   duty cycle for such transmissions does not exceed 0.1%, based on the
   total transmission time during a one-hour interval, and a maximum of
   100 transmissions per hour.

   (4) MedRadio devices operating with a total emission bandwidth not
   exceeding 300 kHz, centered at 403.65 MHz, provided that the transmit
   power is not greater than 100 nanowatts EIRP and the duty cycle for
   such transmissions does not exceed 0.01%, based on the total
   transmission time during a one-hour interval and a maximum of 10
   transmissions per hour.

   (c) Shared access. The provisions of this section shall not be used to
   extend the range of spectrum occupied over space or time for the
   purpose of denying fair access to spectrum for other MedRadio systems.

   (d) Frequency monitoring in the 413-419 MHz, 426-432 MHz, 438-444 MHz,
   and 451-457 MHz bands. MedRadio programmer/control transmitters must
   incorporate a mechanism for monitoring the authorized bandwidth of the
   frequency band that the MedRadio transmitters intend to occupy. The
   monitoring system antenna shall be the same antenna used by the
   programmer/control transmitter for a communications session.

   (1) The MedRadio programmer/control transmitter shall be capable of
   monitoring any occupied frequency band at least once every second and
   monitoring alternate frequency bands within two seconds prior to
   executing a change to an alternate frequency band.

   (2) The MedRadio programmer/control transmitter shall move to another
   authorized frequency band within one second of detecting a persistent
   (i.e., lasting more than 50 milliseconds) signal level greater than −60
   dBm as received by a 0 dBi gain antenna in any 12.5 kHz bandwidth
   within the authorized bandwidth.

   (3) The MedRadio programmer/control transmitter shall be capable of
   monitoring the authorized bandwidth of the occupied frequency band to
   determine whether either direction of the communications link is
   becoming degraded to the extent that communications is likely to be
   lost for more than 45 milliseconds. Upon making such a determination
   the MedRadio programmer/control transmitter shall move to another
   authorized frequency band.

   (e) System shutdown. MedRadio transmitters shall incorporate a
   programmable means to implement a system shutdown process in the event
   of communication failure, on command from the MedRadio
   programmer/control transmitter, or when no authorized alternate
   frequency band is available. The shutdown process shall commence within
   45 milliseconds after loss of the communication link or receipt of the
   shutdown command from the MedRadio programmer/control transmitter. This
   requirement does not apply to MedRadio operations in the 401-406 MHz
   band.

   (f) Requirements for MBAN Networks. A MedRadio programmer/control
   transmitter and its associated medical body-worn transmitters shall not
   commence operating in, and shall automatically cease operating in, the
   2360-2390 MHz band if the programmer/control transmitter does not
   receive, in accordance with the protocols specified by the
   manufacturer, a control message permitting such operation. Medical
   body-worn transmitters shall cease operating in 2360-2390 MHz if they
   lose communication with their associated programmer/control
   transmitter. Additionally, a MedRadio programmer/control transmitter
   and its associated medical body-worn transmitters operating in the
   2360-2390 MHz band shall comply with a control message that notifies
   the devices to limit transmissions to segments of the 2360-2390 MHz
   band or to cease operation in the band.

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