Which type of wireless survey involves physically walking the site and measuring signal strength in real time with APs powered on?

A predictive survey uses RF modeling software to simulate coverage based on floor plan data and AP placement, requiring no physical walkthrough or live APs.

A passive survey uses a wireless adapter in monitor mode to capture beacons and measure RSSI without associating to any AP, so no data session is established and throughput is not tested.

A validation survey is performed after a WLAN is fully deployed to verify that the installed network meets design requirements, not during the initial site characterization phase.

In an active survey the client fully associates with the WLAN and exchanges data frames with the infrastructure while the surveyor moves through the site, producing measurements of actual throughput, packet loss, and roaming behavior. Because real traffic is generated, APs must be deployed and powered on, making this the most realistic pre-deployment validation method for throughput and coverage.