We use many different types of wireless networks every day. In this video, you’ll learn about the 802.11 standards, the use of long-range fixed wireless, RFID, and NFC technologies.
Wireless networks have become almost commonplace in our homes and businesses, and we’ve almost come to expect that when we walk into a restaurant or a conference room that there will be a wireless network available to use. The standards for these wireless networks come from an IEEE LAN MAN standards committee.
This is the IEEE 802 committee. And the wireless networking part of this committee is the 802.11 standard. But as you’re probably aware, there are many different wireless standards. And in this video, we’ll step through each one of those 802.11 standards. Instead of referring to these as 802.11 wireless networks, you’ll often see this abbreviated as a W-Fi network. This is a trademark from the Wi-Fi Alliance, who’s responsible for testing the interoperability of all of these different wireless devices.
The first standard we’ll look at is the one from the very beginning. It’s the 802.11a. This is one of the very first wireless standards that was released back in October of 1999. It’s a standard that operates exclusively in the five gigahertz frequency range. It can use other frequency ranges with special licensing, although these days you don’t often see very many 802.11a networks still around. The 802.11a wireless standard operates at 54 megabits per second. And although this doesn’t seem very fast now, back in 1999 when this was first released, that was a great deal of speed on a network that suddenly was able to operate wirelessly.
Because we are operating at five gigahertz frequencies, we don’t tend to have the same range as lower frequencies such as the 2.4 gigahertz range that’s used by 802.11b. With these higher frequencies, the objects around us tend to absorb the signals, whereas with 802.11b they tend to bounce off of those devices. And therefore, we get a little bit more distance from a 2.4 gigahertz based network. As I mentioned, it’s not common to see 802.11a in use these days. And very often this will be a type of network that has already been upgraded to a much faster and newer standard.
And about the same time that 802.11a was released, the IEEE also finalized the 802.11b standard. This is not an upgrade to the a. Instead this is a completely different standard that operates with different frequencies and different speeds. 802.11b operates in the 2.4 gigahertz range and its maximum speed is 11 megabits per second, which is certainly much slower than the 54 megabits per second we were able to get with 802.11a.
So why would we choose the slower 11 megabit per second wireless standard when a 54 megabit standard already was available? In many cases, this is associated with the frequency in use. As I mentioned earlier, 2.4 gigahertz frequencies tend to bounce off of devices instead of being absorbed. And therefore, we get a bit longer distance in 2.4 gigahertz networks. This, of course, will depend on the type of environment. If you’re in a warehouse, you may choose 802.11a because there’s so much open space. But if you’re in an office setting with a lot of people and desks, you may choose 802.11b because that frequency works a lot better in that environment.
One challenge we have with this 2.4 gigahertz range is that wireless networks are not the only devices that can use those frequencies. It’s very common to see things like baby monitors, cordless phones, or even the Bluetooth standard take advantage of 2.4 gigahertz frequencies. This means that we could have frequency conflicts when trying to communicate using all of these devices simultaneously in one single area. It’s also difficult to find 802.11b networks that might still be operating. And if you do run into an 802.11b network, it’s probably because you’re upgrading it to a newer version.
One of the first upgrades available to these 802.11b networks was the standard for 802.11g. This was released in the June 2003 time frame. And just like 802.11b, 802.11g also operates in the 2.4 gigahertz range. The reason that this was such a useful upgrade for folks running 802.11b was that we increased the speed on the g standard to 54 megabits per second, which is about the same as we found with 802.11a.
This 802.11b g standard is backwards compatible with the b standard. That means that we could upgrade our access point to the 802.11g and still continue to use our b devices on the same network. And although 802.11g operates at higher speeds, it still suffers from the same frequency conflicts that we have with the 802.11b because all of these devices will be using 2.4 gigahertz frequencies.
In 2009, a new standard was released that effectively upgraded 802.11a, b, and g to a new version of 802.11n. As you probably noticed, it can be confusing to keep track of all of these different letters and numbers. So instead of using the standard name of 802.11a or 802.11g, we’re now referring to these standards as Wi-Fi standards. So 802.11n can also be called Wi-Fi 4. Technically speaking, 802.11a, b, and g could also be called Wi-Fi 1, 2, or 3. But because those standards are so old and indeed difficult to find implemented on anyone’s networks these days, we are starting with Wi-Fi 4 as the standards for this numbering scheme.
Because 802.11n or Wi-Fi 4 is designed to upgrade 802.11a, b, and g, this standard is able to operate at both five gigahertz and 2.4 gigahertz simultaneously if your access point supports that. We also have more bandwidth available for each individual channel. We can have up to 40 megahertz channel widths.
And what this really means is we’re able to transfer much more data at the same time over this network. If you do have a wireless access point that’s able to use those 40 megahertz channel widths and it has four antennas on it, you can get a maximum theoretical throughput from 802.11n of 600 megabits per second, which is obviously a large improvement over 802.11a, b, or g.
This 802.11n standard also introduced a new form of communication for wireless networks called MIMO or Multiple Input Multiple Output. This means the devices can transfer much more information simultaneously between the end station and the access point.
In January of 2014, we introduced 802.11ac, which we now refer to as Wi-Fi 5. And this was another improvement over the previous standard of 802.11n. Wi-Fi 5 operates exclusively in the 5 gigahertz range. So unlike 802.11n, there is no 2.4 gigahertz available in Wi-Fi 5. We can also use much more of that wireless spectrum simultaneously because 802.11ac will support up to 160 megahertz of a channel bandwidth.
This translates into more channels that can be used simultaneously and therefore more data that can be transferred over that wireless network simultaneously. This standard also changes how information is transferred over that wireless network. We refer to this as signaling modulation. And this also increased the amount of data that was able to be transferred at any particular time.
This newer 802.11ac standard, not only uses multiple input multiple output but increases the capabilities of that MIMO by adding multi-user MIMO. So multiple users could be communicating over multiple input and multiple output simultaneously. This standard supports up to eight of those multi-user MIMO streams, which translates into a maximum total throughput of nearly seven gigabits per second for 802.11ac.
We mentioned earlier that 802.11ac operates only in the five gigahertz band. But if you look at access points that may be available to buy, you’ll see some of them say that they are 802.11ac access points that operate at five gigahertz and 2.4 gigahertz. In those cases, the communication that’s occurring at 2.4 gigahertz is actually using the 802.11n standard and anything at five gigahertz is using the ac standard.
The upgrade to 802.11ac arrived in February of 2021 with the 802.11ax standard or what we call the Wi-Fi 6 standard. This is a standard that operates at either five gigahertz frequencies or 2.4 gigahertz frequencies and on some access points can use both of those simultaneously. The standard also supports many different channel widths. So we can have bandwidth of 20, 40, 80, and 160 megahertz for people communicating on that wireless network.
If we look at the standards for 802.11ax, we can get a total throughput per channel of about 1.2 gigabits per second. This is a relatively small increase in throughput when you compare it to other improvements in the standards through the years. But there is a difference in how this particular version was designed. 802.11ax was designed to solve some of the problems we have with using these wireless networks in areas where there are large number of people.
So if you’re at a sporting event or a trade show, you may find it difficult sometimes to communicate over these wireless networks. With 802.11ax, we introduced a new form of communicating called orthogonal frequency division multiple access or OFDMA. This takes a type of communication that we’ve used for some time on our cellular networks and brings it into the world of 802.11. This allows us to put 802.11ax networks in places with large numbers of people and be able to communicate without a huge loss in efficiency over those wireless networks.
So here’s the summary of these different standards. 802.11a operated on five gigahertz frequencies and did not have MIMO support. Its maximum theoretical throughput per stream was 54 megabits per second. And in the case of 802.11a, we only had one stream to work with. So we had a maximum throughput of 54 megabits per second. 802.11b operated in the 2.4 gigahertz range and it operated at a maximum throughput at 11 megabits per second. As the upgrade to 802.11b, 802.11g also operated at 2.4 gigahertz and had a maximum throughput of 54 megabits per second.
If you run into an 802.11n network, you can operate it either five or 2.4 gigahertz frequency ranges and can use up to four separate streams of multiple input and multiple output. This gives us a total throughput per stream of 150 megabits per second or a maximum throughput of 600 megabits per second overall. 802.11ac is a five gigahertz technology only. It supports eight downloadable streams of multi-user, multi input, multi output at 867 megabits per second for each stream, making a total theoretical throughput maximum of 6.9 gigabits per second.
And 802.11ax operates at both five gigahertz and 2.4 gigahertz. It also supports eight streams, but the multi-user MIMO in ax supports a download and upload streams simultaneously. That gives us a maximum theoretical throughput per stream of 1.2 gigabits per second and a maximum theoretical throughput of all streams at 9.6 gigabits per second.
If you purchase an access point, bring it home, and plug it in, you’ll probably get a range of about 40 to 50 meters if you’re using the built in antennas. If you’re working in a corporate environment and you want to connect two buildings together with 802.11, then obviously that type of antenna is not going to work. Instead you’ll need some fixed directional antennas and you may need to increase the overall signal strength of the 802.11 signal.
In our offices and homes, we have signals that might be bouncing or be absorbed by the things around us. When we’re sending a signal between buildings, there’s usually not much in the way that would cause the signal to bounce or be absorbed. We would use very directional antennas like this Yagi antenna to be able to have a very focused point to point connection between an antenna on one building and the antenna on the other building.
If you’re planning to set up a long range fixed wireless network, make sure you look at the rules and regulations in your area. Wireless networks have their own complexities associated with them. And when you layer on local and federal rules and regulations regarding wireless communication, it provides some additional challenges to the implementation. If you’re using a wireless service that’s transmitting to your home or you’re trying to connect different wireless services between buildings, you may want to look to see what frequencies are available to use. You may have 2.4 and five gigahertz frequencies available natively in the standard, but there may be other frequencies available that you can apply for which might provide you some advantages over using the busier 2.4 gigahertz or five gigahertz frequencies. You’ll need to check with the 802.11 standards and see what options might be available for the type of network that you’re installing.
Not only are there rules and regulations about what frequencies you can use and where you can use them, there are also regulations about how much of this signal can be sent. There are different regulations on whether these signals will be inside of the building or outside of the building, so make sure you know all of the differences when you’re installing the network.
And ultimately, you’ll need to install an antenna outside if you’re receiving a signal from a service provider or you’re connecting two buildings together. Installing antennas outside have their own set of safety requirements not only in where you install the antenna and that it’s not near any power source, but you also have to make sure that the antenna is protected in case it happens to be hit by lightning. In many cases, it might make more sense to bring in a third party who has an expertise in installing these types of external or outdoor networks.
Another wireless technology that’s widely used is RFID or Radio Frequency Identification. If you have an access badge that unlocks the door by holding it up to a sensor, it’s probably using RFID inside of that badge. If you’re in manufacturing and you have an assembly line or you need to keep track of inventory, then you will extensively use RFID. And we even use RFID at home to keep track of our pets. So if we happen to lose that pet, they can easily be scanned and that identification information will be tied back to you so that your pet can be returned.
This is one type of RFID tag. You can see this one is designed to be cylindrical. And you can see how small it is because it’s next to this grain of rice. If you have an RFID tag inside of your access badge, then it’s probably a flat one like this where the antenna is around the outside and the RFID chip is right in the middle. As you can see in these pictures, there’s often no battery inside of these RFID tags. Instead this uses radar technology. As we send signals out, that signal is being captured by the antenna that is converted to power added to the chip that effectively powers and allows this device to transmit back. Although this is one way to communicate via RFID, there are other RFID tags that do have a power source. We refer to those as active or powered RFID.
We’ve extended the use of RFID into our mobile phones and our smartwatches through the use of NFC. This is Near Field Communication and it’s a way for our mobile devices to be able to have two way conversations with other devices that we might use. For example, we might be checking out at a store and we can use our phone or our smartwatch to pay for those goods because we’ve associated our credit card with the NFC technology that’s in our devices. You might also see NFC used if you need to pair two Bluetooth devices. And because we often carry our phones and our smartwatches with us, we can use NFC to act as an access card so that we can use our phone to unlock a door instead of a separate card.