Wireless LAN Radio Measurements

Wireless LAN Radio Measurements

 General
Wireless LAN (WLAN) Radio Measurements enable STAs to understand the radio environment in which
they exist. WLAN Radio Measurements enable STAs to observe and gather data on radio link performance
and on the radio environment. A STA may choose to make measurements locally, request a measurement
from another STA, or may be requested by another STA to make one or more measurements and return the
results. Radio Measurement data is made available to STA management and upper protocol layers where it
may be used for a range of applications. The measurements enable adjustment of STA operation to better
suit the radio environment. The Radio Measurement service includes measurements that extend the
capability, reliability, and maintainability of WLANs by providing standard measurements across vendors,
and the service provides the resulting measurement data to upper layers in the communications stack.
In addition to featuring standard measurements and delivering measurement information to upper layers,
there are applications that require quantifiable radio environment measurements in order to attain the
necessary performance levels. These applications include VoIP, video over IP, location based applications,
as well as applications requiring mitigation of harsh radio environments (multifamily dwellings, airplanes,
factories, municipalities, etc.). Radio Measurements address most of the existing issues in using unlicensed
radio spectrum to meet the requirements of these emerging technologies.
To address the mobility requirements of technologies, such as VoIP and video streaming, Radio
Measurements, such as Channel Load request/report and the Neighbor request/report, may be used to collect
transition information, which can drastically speed up handoffs between BSSs within the same ESS. By
accessing and using this information, the STAs (either in APs or in non-AP STAs) can make intelligent

decisions about the most effective way to utilize the available spectrum, power, and bandwidth for their
communications.
The request/report measurements are as follows:
— beacon
— frame
— channel load
— noise histogram
— STA statistics
— location configuration information (LCI)
— neighbor report
— link measurement
— transmit stream/category measurement
The request-only mechanism is as follows:
— measurement pause
The report-only mechanism is as follows:
— measurement pilot
These measurement mechanisms provide the capability for a STA to manage and query its radio
environment, and to make appropriate assessments about its health and efficiency. It is the first step in
making WLAN smart and capable of making appropriate decisions for fast transition, for mesh connectivity,
and for managing the radio environment for all wireless devices.