Lightings impact on WiFis performances

efecto fluorescentes Xiaomi6

February 5, 2024 - Our company is specialized in measuring the performance of WiFi equipment. For this purpose, we have a lab in Madrid and among other things, we can carry out the Broadband Forum TR-398 (WiFi In-Premises Performance Testing) recommendations.

When testing different equipment, we have detected that the performance of WiFi Access Points (AP) cab be affected by the type of lighting used in the rooms.


As WiFis use radio bands at 2.5GHz, 5GHz and now also 6GHz, devices that emit radio frequencies around can reduce the signal-to-noise ratio (S/N) and then lead to modulation interferences and/or packets retries. Overall, the "thoughput" of our WiFi devices is reduced.

Examples of radio interference known sources are motors, microwaves and Bluetooth equipment. There is also literature indicating that different types of luminaires (e.g. fluorescent) can cause interference. In this case, to explain this phenomenon there are different possibilities (e.g. defective quality of electrical installations, lighting, etc.). However, even with a good installation, interference can occur. For example, in the case of fluorescents, a side effect of radio wave emission (MHz) occurs due to thermionic emissions (when an electric arc passes through the mercury vapor inside the fluorescent).

Although it seems unlikely that the frequencies generated by these emissions (MHz bands) can affect our WiFis that work in GHz bands, they can produce interference due to intermodulation.

By way of illustration, in the following graph we can see how a WiFi signal carrier can be affected by the frequencies generated by fluorescent lights:


However, we have found little experimental works studying this problem. Thus, and in order to have a prior calibration of our tests measurements, in those locations where we suspect that the electrical and lighting installation is not very modern, we carry out tests with lights off and lights on.

Here you can see a graph with the results of an analysed case by our company with APs on ceilings:

efecto fluorescentes Xiaomi6

Here the test consists of 8 ax stations (WiFi6), distributed around the open space of the office, illuminated with fluorescents, connected to a WiFi6 AP.

We can see that with the fluorescent lights on, the throughput that the AP can process is reduced by more than 20%.

In the following photos you can see the test instrumentation, Candela Technologies equipment, with which we use to generate the WiFi6 stations and the location of the APs vs luminaires:

Equipos Candela1oficina1

As this distribution of APs on ceilings and with nearby luminaires (1m or 2m) is very typical for offices and public spaces, this problem may be more common than expected. So in many cases we are getting less speed on our WiFis because of the lights.

From our experience, to solve this problem there are two approaches:

  • Redistribute the APs on the ceilings, separating them at least 3m away from the luminaires
  • Change fluorescent lights for quality LED lights

In both cases, we recommend verifying later that the changes have managed to minimize interference.