Wireless Network Technologies – CompTIA A+ 220-1101 – 2.3

There are many different technologies used to support our wireless network connections. In this video, you’ll learn about frequency use, channel designations, regulations, band selections, and Bluetooth connectivity.

If you’re using an 802.11 network, there are a number of technical specifications that you need to be aware of. One is the frequency in use. You may have already seen in the 802.11 standards video that there are many standards that use the 2.4 GHz range, and other standards that use the 5 GHz range, and some of them use both of those ranges to be able to communicate.

You also have to keep in mind that there are separate channels within those frequency ranges that can be used. These are groups of frequencies. And the IEEE has assigned numbers to these frequencies so that we can much easier refer to which channel we happen to be using. That’s why we often say if you’re using multiple access points in a particular area, you may want to make sure each of the access points is running on a different wireless channel.

And depending on where you are in the world, there’s probably a governmental agency that’s responsible for managing the wireless spectrum or the frequencies that you would use for these 802.11 networks. These regulations often dictate exactly which frequencies should be used. They’ll specify the maximum amount of power that can be used on those networks. And they’ll set requirements and limits over how much interference can be caused by these 802.11 networks.

We often see the 2.4 GHz and 5 GHz networks compared with 802.11. But I thought it’d be nice to see a visual representation of why the 5 GHz networks are so popular. Let’s start with 2.4 GHz networks. These are the networks commonly seen as IEEE’s channels 1, 6, and 11. And these are three separate 20 megahertz bandwidths that range from 2412 MHz through 2482 MHz. And that’s where we get the 2.4 GHz band information.

These are the only channels available in 2.4 GHz. As you can see, there are three to choose from. And if you’re in an apartment complex with many 802.11 wireless networks, you’ll easily find a lot of activity on all three of those channels. Because of these limitations for 2.4 GHz, we had to find some other available frequencies to use. So we started using the 5 GHz spectrum. Everything that is on this 5 GHz list that is not red can be used to communicate.

So you can see, there are many more 20 MHz channels available on a 5 GHz spectrum than there ever was on 2.4 GHz. This allows you to easily find some available spectrum in your area, especially if there are a lot of access points being used simultaneously. You may be using larger bandwidth than 20 MHz to communicate because you can get much better throughput that way.

So it may not be 20 MHz channels that you’re choosing. It may be a 40 MHz bandwidth, an 80 MHz bandwidth, or the current largest 160 MHz bandwidth. You can see when you get to 160 MHz that there are really two separate non-contiguous areas available to be able to communicate at such a large bandwidth.

Not only do we often use these 802.11 wireless networks, we also extensively use Bluetooth networks. This effectively removes the wires from our peripherals that we connect to our mobile devices. So if you’re using a headset, if you have a set of external speakers, or you have an external keyboard that you use on your computer, it’s probably using Bluetooth to communicate.

Bluetooth also uses the 2.4 GHz band. The part of 2.4 GHz it uses is the unlicensed ISM part of the band that stands for industrial, scientific, and medical. This is an area of the 2.4 GHz band that doesn’t require you to get any special licensing from the government. Anyone can use these particular frequencies. And that’s why Bluetooth and 802.11 commonly use the 2.4 GHz band.

Bluetooth devices generally only communicate in a small area around you. We often refer to this as a personal area network because of that. So most of the headsets and other devices you’ll use will probably operate to about 10 meters in distance.

If you’re in an environment that uses industrial Bluetooth, there are additional standards available that can increase that distance to over 100 meters. But if you’re using consumer devices, you’re probably not using a 100 meter distance between you and your headset. Instead, we can use the Bluetooth standards that limit that to about 10 meters.