By far the most questions we get here at Rivet Networks revolve around WiFi networking.  Most of these questions can be solved with some basic knowledge of how WiFi networking works and how to configure your WiFi networks to be more effective.

WiFi is a shared medium.  Think of it like those old Walkie Talkies we all had as kids.  You press the talk button and everyone else who has one of those walkie talkies can hear you.  You would say “over” so everyone knew when you were done talking.  If 2 people tried to talk at the same time, no one heard anything.  And there was always the jerk who would hold the talk button down to prevent anyone else from talking.  That is how WiFi works except instead of 2 or 3 people, WiFi routers can have dozens of endpoints, which makes the issues multiply very fast.  Each endpoint listens, and if it does not hear anyone transmitting it transmits.  This usually works but when multiple endpoints want to transmit at the same time, they both can hear silence and then both can transmit at the same time.  They will recognize the “collision” but it means that no one transmitted during that window.  On top of that, both endpoints need to retransmit.  They each pick a random number, wait a period of time based on that number and try again, hoping that they do not collide gain.

WiFi operates on 2 bands: 2.4 GHz and 5 GHz.  Almost all WiFi chips and modules produced since 2012 support both bands.  Each band is broken up into channels. 2.4 GHz has up to 4 channels and 5 GHz has up to 15 channels.   In general, the goal is to use a different channel then all the other routers in the vicinity.  This is because if 2 routers use the same channel, then all the WiFi endpoints on both routers will share the channel and so they will compete against each other for transmission time.  It is similar to if all the endpoints were connected to the same router but worse because now you also have the 2 routers competing with each other.

Given that channel selection is so important, how do WiFi channels get selected?  The channel selection is done by the router usually when it is turned on.  It scans all the channels and picks one that has the least competition.  While this sounds good in theory, if your router is a good one, you may only restart it when there is a power outage.  Which means, if someone adds a new router or even restarts their existing router, the channel your router is on may no longer be the best one.

Using Killer WiFi Analyzer

If you launch the Killer Control Center and select the WiFi Analyzer analyzer tab you will see how crowded your WiFi environment is.

You can select the WiFi band in which you are interested.  If you find your band is crowded, you can restart your router and see if it picks a better channel.  If not, most routers let you configure the WiFi channel your radio will use.

One final thought, remember the most important thing is to be on a channel with the fewest busy endpoints.  Sometimes there is a router very close that no one is on so picking the same channel as an unpopular router is often better than picking the channel of a popular router farther away.  Being on the same channel as a router with no password is often the worst because they tend to have the most endpoints.

These tips ought to be enough to get you started on your way to a better WiFi network experience.