Why is my Wi-Fi so slow?

Posted by Liz Sujka on 12/01/17 03:06 PM
Liz Sujka

When it comes to Wi-Fi one of the most common questions expressed by consumers is, "Why is my Wi-Fi so slow?" Is that a perception or is that a reality?  Do Wi-Fi networks really consistently under-perform?   Well, lets take a look at how Wi-Fi functions at least by default here in the US.

cisco router.jpg

We've compiled a list of 10 Tips To Improve Your Wi-Fi Signal and overal router functionality. Click to download your handy guide to making the most of your Wi-Fi, your router will thank you! Read on and continue to learn more about the science behind the radio waves that power your Wi-Fi.

 Click For Instant Download!  10 Wi-Fi Speed Tips

Most people are familiar with the two main frequencies or bands for Wi-Fi - 2.4 GHz and 5 GHz.  But, what does that really mean? The 2.4 GHz band covers 80 megahertz of total bandwidth and is divided into 11 channels.  That sounds impressive right? Well, considering that one connection requires 5 channels - used consecutively.  By default these are usually channels 1, 5 and 11. So, net result here is that on a 2.5Ghz band you only get 3 transmissions occurring at the same time.  Yikes - That could mean there is a great deal of competition for channel space.  Taking this one step further, if you can see more than 2 networks within the range of your device, it is likely that you are experiencing interference.  


Interference means that more than one network is trying to use the same channel at the same time.  It is by design that the Wi-Fi standard causes network delay.  Wi-Fi uses listen-before-you-talk technology called clear channel assessment (CCA) to ensure that only one radio can transmit on the same channel at any given time.  If the AP signals continue to compete for the same channel the delay time that occurs between resets increases exponentially this is called - "back-off".  As there are more collisions between competing networks, "back-off"  increases and guess what happens to your network performance?  You got it - it massively degrades.  

A familiar example is, the Wi-Fi experience at a hotel.  <insert sigh here>  The hotel provides Wi-Fi - excellent!  But, when you connect, you see 5 different AP's you can connect with.  Maybe it is setup by floor.  So, you select the AP named 4th floor, you join the network.  It's not fast but everything is going smoothly until you get kicked off.  You assume it is because of the poor internet speed.  Not likely!  Most likely it is due to our friend interference.  With each Wi-Fi device rapidly turning on and off trying to get an open channel, network congestion is an inevitable result. 

Thankfully there is a 5GHz spectrum available.  This preferred band now offers 24 non-overlapping channels.  Which is a major difference from the 3 we had on 2.4GHz.  Some of these are reserved for government use however, there really is no comparison between the channel availability found in 5GHz vs 2.5GHz.  

Your next question should be, "What about interference?"
To this question, the answer is the same. It is possible and likely with multiple access points, in a  non configured space, you will still have interference.  However, with more channels, there is a greater likelihood that the "back-off" will not be as predominate.  

The good news is that Wi-Fi standards are increasing capabilities as demand is generating.  Over the next few years, it will be interesting to see how Wi-Fi can keep up with demand and as the IOT grows up, we can be sure that wireless device counts will only be increasing. 


Click For Instant Download!  10 Wi-Fi Speed Tips