§  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]