What is co-channel interference

Co-channel interference is important to understand when designing and deploying a WiFi network.

So, co-channel interference (CCI) occurs between two access points (APs) that are on the same frequency channel.

In WiFi Scanner there is a tab that allows you to see co-channel interference in real-time. Under the Signal summary tab in the middle of the page located here in blue 

Look toward the right and notice Co-channel interference. As you can see I have no Co-channel interference from outside networks. Yours will look different.