WLAN Design & Site Survey Flashcards

What type of site survey involves walking through a facility to assess RF coverage without associating to any access point?

Answer: Passive survey

A passive survey captures existing RF signals by listening only, without associating to an AP, making it ideal for assessing the existing RF environment.

What is the primary purpose of a predictive site survey?

Answer: To model WLAN coverage using floor plan software before deployment

Predictive surveys use specialized software to model expected RF coverage from proposed AP placements on a floor plan before any hardware is installed.

Which tool is best suited for identifying non-802.11 RF interference sources such as microwave ovens or DECT phones during a site survey?

Answer: Spectrum analyzer

A spectrum analyzer can detect and identify non-802.11 RF energy sources across a frequency range, which protocol analyzers cannot do since they only decode 802.11 frames.

What is the recommended minimum RSSI for supporting Voice over Wi-Fi (VoWiFi) applications?

Answer: -67 dBm

Voice over Wi-Fi applications typically require a minimum RSSI of -67 dBm to maintain the consistent signal quality needed for real-time voice communications.

In WLAN design, what does 'cell overlap' refer to?

Answer: The area where the coverage zones of two or more APs intersect

Cell overlap is the intentional area where signals from adjacent APs intersect, which is required so that roaming clients can detect the next AP before losing the current one.

What percentage of cell overlap is generally recommended between adjacent APs to support seamless roaming for data applications?

Answer: 15-20%

A 15-20% cell overlap provides sufficient coverage continuity for clients to detect and initiate roaming to the next AP before the current signal becomes unusable.

What is the purpose of measuring the 'noise floor' during a site survey?

Answer: To establish the baseline RF interference level present in the environment

Measuring the noise floor establishes the baseline level of ambient RF interference in the environment, which is essential for calculating signal-to-noise ratio requirements.