At Behind The Sciences, we are always pleased to launch a new category and we think this one is going to be specially interesting for you! 🙂
In our new WiFi category, we want to show you some handy tips and tricks so you can improve your understanding on this standard and get updated on the latest news. What’s more, you’ll be able to apply what you learn here in your own WiFi network at home or at work.
In this post, we are going to start with some basic but important concepts, so you can make sure you are getting the maximum out of your WiFi network.
1.- Selecting the best WiFi band: 2.4 GHz or 5GHz
You’ve probaby observed that in your router configuration url, you can configure WiFi 2.4GHz and WiFi 5GHz. Actually, these two “types of WiFi” correspond with different standards and have different characteristics.
The following table shows the main differences:
Having a look at the previous table, it looks like the best standard to select is 802.11ac. However, there are some other parameters depending of the band selected that we need be aware of:
2.4 GHz Pros
- Bigger range of coverage than 5GHz, as these frequencies are less vulnerable to obstacles reflection
- It can probably works with older devices that may not have 5GHz tech yet
2.4 GHz Cons
- Because there are more devices that support 2.4GHz than those which support 5GHz, this band is busier and we can get more interferences
- Lots of devices use this band: kitchen microwaves, baby’s walkies, headphones, bluetooth…hence, more sources of interference
- The bandwiths are smaller (as we’ll see in a bit)
5 GHz Pros
- Not all devices support it, so it’s less crowded
- At these frequencies, the signals can’t conduce through obstacles, so we can get better isolation from outside networks
- Bigger bandwidths
5 GHz Cons
- Your older devices may not have it (who doesn’t have a 6 years old iPad which works perfectly or even a Raspberry Pi?)
- The isolation also means you may need an additional AP to get to different rooms
Which one you should select?
From the points above, you may already realized:
To cover big buildings with minimum number of AP: better to use 2.4GHz, specially if the building is in a location where not external WiFis can interfere. For instance, a house with no many neighbours. In this case, the range of coverage will be extense but the throughput will be limited.
To cover a room with maximum throughput and a single AP: you can use 5GHz, as it’ll be isolated from outside and will provide better performace. This is useful for conference meetings, where there are also lots of people wanting to connect.
2.- Do I need to manually select the channel?
Once, you select your band, it’s time to talk about the channel you are using. One key thing to bear in mind is that the channel that it’s suitable today, may not be suitable tomorrow…
Setting the WiFi channel in Auto mode
In the settings of your WiFi router, by default, probably your channel has the Auto mode enabled. The router has a mechanism to select the best one each moment. However, loosing the control on the channel selection, can affect your WiFi performance. The following 2 subsections show something similar to the mechanism your router uses, so you can also do it manually to get full control over it.
Channels in the 2.4GHz band
Although each country has its own regulations, generally speaking, if you are connected to this band, you’ll be using one of the channel from 1 to 14. Even if 14 channels look like it it’s enough, there is a limitation in the 22 MHz channel bandwidth because there is overlapping amon them:
This means, ideally, we should get a channel which is separated at least 5 channels from a busy one. For example, if you neighbour is using channel 1, you should use channel 6 so there is no overlapping.
If this is not possible, we should select the channel which is more separated of the weaker channel (in terms of power).
For instance, we have a network with 2 APs which are overlapping with smaller transmission power ones, NataliaMovil and bts_wifi:
As you can see in the picture above, our two APs are the strongest ones and they are using channels 1 and 6 (by the way, this is an app called “WiFi Analyzer” that we definitely recommend).
According to the 802.11b standard, the non-overlapping channels are:
Channels in the 5GHz band
In this band, we have at least 24 channels to select:
Some of the terms you see in the table are DFS = Dynamic Frequency Selection; TPC = Transmit Power Control; SRD = Short Range Devices 25 mW max power.
DFS is a radar system mechanism and it can stop the AP transmission temporary. In addition, if you select one of these channels, the AP can be scanning for radar signal up to 10 minutes (depending on the manufacturer). Therefore, when you select the Auto mode, changing to one of these channels can have a huge impact in your WiFi connectivity.
We hope after this post you can apply a few tips to improve your WiFi network. In following posts, we will show you more tricks such as transmit power configuration, types of antennas, repeaters… our goal here is explain you the sciences behind the WiFi 😉 so you can easily put in to practice what you’ve learnt.