#### § 15.403 Definitions.

*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 or as a relay between wireless network segments.

*Automated Frequency Coordination (AFC) System.* A system that automatically determines and provides lists of which frequencies are available for use by standard power access points operating in the 5.925-6.425 GHz and 6.525-6.875 GHz bands.

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

*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.

*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.

*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.

*Client Device.* A U-NII device whose transmissions are generally under the control of an access point and is not capable of initiating a network

*Contention-based protocol.* A protocol that allows multiple users to share the same spectrum by defining the events that must occur when two or more transmitters attempt to simultaneously access the same channel and establishing rules by which a transmitter provides reasonable opportunities for other transmitters to operate. Such a protocol may consist of procedures for initiating new transmissions, procedures for determining the state of the channel (available or unavailable), and procedures for managing retransmissions in the event of a busy channel.

*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.

*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.

*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.

*Emission bandwidth.* For purposes of this subpart the emission bandwidth is 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.

*Fixed client device.* For the purpose of this subpart, a client device intended as customer premise equipment that is permanently attached to a structure, operates only on channels provided by an AFC, has a geolocation capability, and complies with antenna pointing angle requirements.

*Indoor Access Point.* For the purpose of this subpart, an access point that operates in the 5.850-5.895 GHz or the 5.925-7.125 GHz band, is supplied power from a wired connection, has an integrated antenna, is not battery powered, and does not have a weatherized enclosure. Indoor access point devices must bear the following statement in a conspicuous location on the device and in the user's manual: FCC regulations restrict operation of this device to indoor use only.

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

*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.

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

*Maximum Power Spectral Density.* The maximum power spectral density is the maximum power spectral density, within the specified measurement bandwidth, within the U-NII device operating band.

*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.

*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 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.

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

*RLAN.* Radio Local Area Network.

*Standard Power Access Point.* An access point that operates in the 5.925-6.425 GHz and 6.525-6.875 GHz bands pursuant to direction from an Automated Frequency Coordination System.

*Subordinate Device.* For the purpose of this subpart, a device that operates in the 5.850-5.895 GHz band or in the 5.925-7.125 GHz band under the control of an Indoor Access Point, is supplied power from a wired connection, has an integrated antenna, is not battery powered, does not have a weatherized enclosure, and does not have a direct connection to the internet. Subordinate devices must not be used to connect devices between separate buildings or structures. Subordinate devices must be authorized under certification procedures in part 2 of this chapter. Modules may not be certified as subordinate devices.

*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.

*U-NII devices.* Intentional radiators operating in the frequency bands 5.15-5.35 GHz, 5.47-5.895 GHz, and 5.925-7.125 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.

*Very low power device.* For the purpose of this subpart, a device that operates in the 5.925-6.425 GHz and 6.525-6.875 GHz bands and has an integrated antenna. These devices do not need to operate under the control of an access point.

[85 FR 31410, May 26, 2020, as amended at 86 FR 23295, May 3, 2021; 89 FR 890, Jan. 8, 2024]