|The Federal Communications Commission (FCC) is the authority
in the United States of America that creates and enforces the use of airwaves throughout the entire
radio frequency spectrum. This group of documents contains the entirety of the
FCC Part 15 regulations
that concern unlicensed radio frequency devices. As with all government documents, this material
is in the public domain and may be freely copied so long as the content is not changed. This copy
is provided as a convenience for RF Cafe visitors.
Click here for the
Table of Contents.
[Code of Federal Regulations]
[Title 47, Volume 1]
[Revised as of October 1, 2008]
From the U.S. Government Printing Office via GPO Access
CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION
PART 15_RADIO FREQUENCY DEVICES--Table of Contents
Subpart E_Unlicensed National Information Infrastructure Devices
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
(p) Pulse. A pulse is a continuous transmission of a sequence of
modulation symbols, during which the average symbol envelope power is
(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]