RF site survey
A process used to determine the number and placement of access points (AP) that provides adequate coverage throughout the facility. With wireless systems, it's difficult to predict the propagation of radio waves and detect the presence of interfering signals without the use of test equipment. As a result, it's often necessary to perform a RF site survey to fully understand the behavior of radio waves within a facility before installing wireless network access points.
The ultimate goal of a RF site survey is to supply enough information to determine the number and placement of access points that provides adequate coverage throughout the facility. In most implementations, adequate coverage means support of a minimum data rate. A RF site survey also detects the presence of interference coming from other sources that could degrade the performance of the wireless LAN.
See "RF Site Survey Steps" on Wi-Fi Planet.