[Wi-Fi Clinic] Why is my Wi-Fi unstable? | Channel Selection

Treatment

Solution to each types of interference are conceptually as simple as “avoid hearing other audio source”. How do achieve this? Basically, we are trying to separate target (desired) AP from interference source in either physical distance or channel distance so they are far enough and can’t hear each other.

Non-Wi-Fi Interference Solution

  • Increase physical distance
  • Decrease transmission power by replacing with alternative device

Conceptually, the solution for NWI is to avoid using those devices all together i.e. extreme of decrease transmission power of the interference source or place them physically far enough distance from your router/access point. Avoid using the device all together may sound a too extreme and may be impossible but there may be an alternative version of the device that use either Wired connection or standard Wi-Fi connection.

For example, analog or non-Wi-Fi security camera can be a source of high severity of NWI but nowadays there are many Wi-Fi based security camera so using such device solve the NWI from it (ref).

Radar signal as the worst form of NWI in DFS Channels

Dynamic frequency selection (DFS) channels are special channels in the 5 GHz band. Both client and AP must support these channels in order for one to be able to use it. The DFS Channels open more channel space/options to users; however, these channels are special because they must follow a special rule that is “you can use it only if radars are not using it.” This rule results in main disadvantages when DFS Channels are used in comparison to non-DFS channels: (ref, ref)

  • AP must change the channel if radar signal is detected. This results in sudden complete disconnect.
  • AP must make sure DFS channel is available to use. This results in longer time associating with DFS channel i.e. slower roaming.

So in 5 GHz band, there are people advocating to avoid using DFS channel.