Sec.  15.403   Definitions.

   (a) Access Point (AP). A U-NII transceiver that operates either as a bridge
   in a peer-to-peer connection or as a connector between the wired and
   wireless segments of the network.

   (b) Available Channel. A radio channel on which a Channel Availability Check
   has not identified the presence of a radar.

   (c) Average Symbol Envelope Power. The average symbol envelope power is the
   average, taken over all symbols in the signaling alphabet, of the envelope
   power for each symbol.

   (d) Channel Availability Check. A check during which the U-NII device
   listens on a particular radio channel to identify whether there is a radar
   operating on that radio channel.

   (e) Channel Move Time. The time needed by a U-NII device to cease all
   transmissions on the current channel upon detection of a radar signal above
   the DFS detection threshold.

   (f) Digital modulation. The process by which the characteristics of a
   carrier wave are varied among a set of predetermined discrete values in
   accordance with a digital modulating function as specified in document ANSI
   C63.17–1998.

   (g) Dynamic Frequency Selection (DFS) is a mechanism that dynamically
   detects signals from other systems and avoids co-channel operation with
   these systems, notably radar systems.

   (h) DFS Detection Threshold. The required detection level defined by
   detecting a received signal strength (RSS) that is greater than a threshold
   specified, within the U-NII device channel bandwidth.

   (i) Emission bandwidth. For purposes of this subpart the emission bandwidth
   shall be determined by measuring the width of the signal between two points,
   one below the carrier center frequency and one above the carrier center
   frequency, that are 26 dB down relative to the maximum level of the
   modulated carrier. Determination of the emissions bandwidth is based on the
   use of measurement instrumentation employing a peak detector function with
   an instrument resolution bandwidth approximately equal to 1.0 percent of the
   emission bandwidth of the device under measurement.

   (j) In-Service Monitoring. A mechanism to check a channel in use by the
   U-NII device for the presence of a radar.

   (k) Non-Occupancy Period. The required period in which, once a channel has
   been recognized as containing a radar signal by a U-NII device, the channel
   will not be selected as an available channel.

   (l) Operating Channel. Once a U-NII device starts to operate on an Available
   Channel then that channel becomes the Operating Channel.

   (m) Peak Power Spectral Density. The peak power spectral density is the
   maximum power spectral density, within the specified measurement bandwidth,
   within the U-NII device operating band.

   (n) Maximum Conducted Output Power. The total transmit power delivered to
   all antennas and antenna elements averaged across all symbols in the
   signaling alphabet when the transmitter is operating at its maximum power
   control level. Power must be summed across all antennas and antenna
   elements. The average must not include any time intervals during which the
   transmitter is off or is transmitting at a reduced power level. If multiple
   modes of operation are possible (e.g., alternative modulation methods), the
   maximum conducted output power is the highest total transmit power occurring
   in any mode.

   (o) Power Spectral Density. The power spectral density is the total energy
   output per unit bandwidth from a pulse or sequence of pulses for which the
   transmit power is at its peak or maximum level, divided by the total
   duration of the pulses. This total time does not include the time between
   pulses during which the transmit power is off or below its maximum level.

   (p) Pulse. A pulse is a continuous transmission of a sequence of modulation
   symbols, during which the average symbol envelope power is constant.

   (q) RLAN. Radio Local Area Network.

   (r) Transmit Power Control (TPC). A feature that enables a U-NII device to
   dynamically switch between several transmission power levels in the data
   transmission process.

   (s) U-NII devices. Intentional radiators operating in the frequency bands
   5.15–5.35 GHz and 5.470–5.825 GHz that use wideband digital modulation
   techniques and provide a wide array of high data rate mobile and fixed
   communications for individuals, businesses, and institutions.

   [ 69 FR 2687 , Jan. 20, 2004, as amended at  69 FR 54036 , Sept. 7, 2004]