DEFINITIONS - 15

receive power: Mean power measured at the antenna connector.
received channel power indicator (RCPI): An indication of the total channel power (signal, noise, and
interference) of a received frame measured on the channel and at the antenna connector used to receive the
frame.
received power indicator (RPI): A quantized measure of the received power level as seen at the antenna
connector.
received signal to noise indicator (RSNI): An indication of the signal to noise plus interference ratio of a
received frame. RSNI is defined by the ratio of the received signal power (RCPI-ANPI) to the noise plus
interference power (ANPI) as measured on the channel and at the antenna connector used to receive the
frame.
NOTE—RCPI and ANPI might not be measured simultaneously; see 10.11.9.4 for details.
registered station (STA): A STA for which information needs to be submitted to an appropriate regulatory
or coordination authority before it is allowed to transmit.
remote request broker (RRB): The component of the station management entity (SME) of an access point
(AP) that supports fast basic service set (BSS) transitions over the distribution system (DS).
resource information container (RIC): A sequence of elements that include resource request and response
parameters.
restricted channel: A radio channel in which transmission is restricted to stations (STAs) that operate under
the control of licensed operators.
roaming consortium: A group of subscription service providers (SSPs) having inter-SSP roaming
agreements.
Robust Management frame: A management frame that is eligible for protection.
scheduled service period (SP): The SP that is scheduled by the quality-of-service (QoS) access point (AP).
Scheduled SPs start at fixed intervals of time.
service interval (SI): The interval between the start of two successive scheduled service periods (SPs).
service period (SP): A contiguous time during which one or more downlink individually addressed frames
are transmitted to a quality-of-service (QoS) station (STA) and/or one or more transmission opportunities
(TXOPs) are granted to the same STA. SPs are either scheduled or unscheduled. For a non-access-point
(non-AP) STA, there can be at most one SP active at any time.
service set transition: A STA movement from one BSS to another BSS, i.e., either a BSS transition or an
ESS transition.
serving AP: The AP to which the STA is associated.
sounding: The use of preamble training fields to measure the channel for purposes other than demodulation
of the Data portion of the physical layer convergence procedure (PLCP) protocol data unit (PPDU)
containing the training fields.
NOTE—These uses include calculation of transmit steering, calculation of recommended MCS, and calculation of calibration
parameters.