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Wireless & Mobility · Foundational

Noise Floor

The ambient level of background RF energy on a channel, measured in dBm.

Definition

The noise floor is the sum of all unwanted RF energy that is not a decodable signal. Typical indoor 2.4 GHz and 5 GHz noise floors range from about -90 to -100 dBm. A raised noise floor reduces SNR and therefore achievable data rates.

Example

A microwave oven can raise the 2.4 GHz noise floor from -95 dBm to -80 dBm.

Exam tip

Noise floor is a negative dBm value; a higher (less negative) floor is worse.

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