Interconnected World
In today’s interconnected world, Wi-Fi has become an essential part of our daily lives. But have you ever wondered how Wi-Fi works, or how different Wi-Fi standards differ from each other?
Wi-Fi Standards
Shown here are the different Wi-Fi standards. For the A+ exam, you need to know a little about the major standards. The most important part to remember is the letter at the end of the standard and the order.
You also need to remember the frequency. You may get asked which standards use which frequencies.
To make it easier to remember the standards, the convention of using the word “Wi-Fi” followed by a number was created. The latest Wi-Fi standard is Wi-Fi 7. Wi-Fi 7, at the time this video was created, is not an exam objective as it was only released in 2024.
The first three Wi-Fi standards have retrospectively been assigned the designations “Wi-Fi 1,” “Wi-Fi 2,” and “Wi-Fi 3.” While this naming convention was not used in the early days of Wi-Fi, you may occasionally encounter individuals referring to these older standards using the newer convention.
I will now have a look at each standard in more detail.
802.11a (Wi-Fi 2)
Technically speaking, 802.11a was the first Wi-Fi to be developed. However, it was slow to take off compared with 802.11b. It faced compatibility challenges with existing devices and cost more than 802.11b. Thus, although being the first to be developed, it ended up finishing second in the race for market acceptance. Because of this, the standard was retroactively called Wi-Fi 2, since it was the second standard to gain market acceptance. Now you know why the first two standards are out of order.
802.11a operates in the 5 GHz band. The indoor range is about 30 meters or 100 feet. However, the actual range can vary depending on factors such as the number of walls and other obstacles between the router and the device. This band is divided up into a number of different channels. Where you live in the world and regional regulations will determine which channels you can use.
If you are using the 5Ghz frequency, most countries will require the Wi-Fi device to implement Dynamic Frequency Selection or DFS. Any channel in the DFS range will be disabled if radar is detected in that range. The Wi-Fi router, when it detects radar on that channel, will essentially move to another channel. You won’t lose all the channels in the DFS range, but some radar uses more channels than others.
Due to the wide spacing between Wi-Fi channels, adjacent channels typically don’t interfere with each other. Therefore, even if some channels are unusable due to radar, there are plenty of other channels available.
The maximum speed of 802.11a is 54 Megabits per second. That is not a lot nowadays. Given its slow speed and the fact that it was released in 1999, you are unlikely to come across devices that use this standard.
The main takeaway from this is, get familiar with the channels in the 5Ghz range and that 802.11a exists. It is unlikely you will be supporting devices that use it. You may find that your Wi-Fi router has an option to disable it.
802.11b (Wi-Fi 1)
802.11b was also released in 1999, so you are unlikely to come across it. Compared with 802.11a, it uses poor encoding methods and thus could only reach a maximum speed of 11 Megabits per second. However, it took off because it was cheaper and more compatible with older technology making it easier to implement.
The 2.4 GHz frequency band, known for its broader indoor coverage, boasts a range of up to 45 meters (or approximately 150 feet), surpassing the 5 GHz band by about 15 meters (or 50 feet). While both frequency bands are impacted by physical structures and objects, the 2.4 GHz spectrum is less affected than its 5 GHz counterpart. This lesser degree of interference from buildings and objects makes the 2.4 GHz range more reliable for indoor use, especially in environments with numerous physical barriers. This is another reason why it had a lot of early market adoption over the 5 GHz range.
The channels used by the 2.4 GHz range do overlap, so adjacent channels can cause interference with each other. Channel 6 tends to be the default channel used by many Wi-Fi routers, since it is in the middle and thus, if there are no other devices using the 2.4 GHz range, it should be pretty good.
802.11g (Wi-Fi 3)
The next standard, 802.11g, essentially, adopts the encoding technique of 802.11a. As a result, it achieves the same maximum speed of 54 Megabits per second. If I consider a router from this time period, it works like this: 802.11b had poor encoding but used the 2.4 GHz range.
802.11a had good encoding. So, to implement 802.11g on our router, the encoding was simply upgraded. Now we have a Wi-Fi router that uses the same encoding as 802.11a but uses the 2.4 GHz frequency. Since the router supported this encoding, it was a simple matter for the manufacturer of the Wi-Fi router to add the 5 GHz frequency.
As this standard was released in 2003, as with the previous standards, you are unlikely to come across it. Newer standards of Wi-Fi started drastically increasing the speed.
802.11n (Wi-Fi 4)
802.11n was released in 2008. Officially also known as Wi-Fi 4, it has a maximum speed of 600 Megabits per second. There are, however, some caveats to getting these higher speeds. In this video, I won’t be looking at the improvements to the encoding which also increases the bandwidth. Just keep in mind that, starting with Wi-Fi 4, they are always making improvements to the encoding of data which increases the speed. This video will just be looking at the other improvements that increase speed.
Wi-Fi 4 introduced Multiple-Input, Multiple-Output (MIMO) technology, which enables the combination of up to four data streams to boost transmission speeds. The actual number of supported data streams depends on both the Wi-Fi router and the device, with each data stream requiring a dedicated antenna. While routers with at least four antennas are necessary for maximum MIMO performance, router manufacturers may limit the number of concurrent streams. Therefore, checking router specifications is crucial to determine the actual number of supported data streams.
Adding four antennas to a mobile device can be pretty costly, thus Wi-Fi 4 added another way to increase the bandwidth using the one antenna.
802.11n (Wi-Fi 4)
Wi-Fi 4 adds another feature called channel bonding. This allows two channels to be combined together to increase bandwidth; however, it can only be used on the 5 GHz frequency. In the 5 GHz band, channels are spaced farther apart compared to the 2.4 GHz band. This wider spacing significantly reduces the chance of interference between channels.
Given that the channels are 20 MHz apart, channel bonding basically creates 40 MHz channels. Having a larger frequency allows for more bandwidth. Keep in mind that DFS still applies, thus if radar is being used in your area, this will reduce the number of channels that are available.
MIMO can also be used with channel bonding. To get the maximum speed with Wi-Fi 4, you need four channels of 40 Megahertz. As you can see, there are caveats with Wi-Fi to getting the maximum speed. The maximum speed a device supports will be determined by the frequency used, if it is bonded, and how many channels it can use. So don’t always believe the speed written on the box. You need to read the specifications of the device and the wireless point to determine what sort of speeds you will get.
802.11ac (Wi-Fi 5)
In 2014, Wi-Fi 5 was released. This standard only used the 5GHz frequency. This standard supports up to eight data streams and offers wider frequencies, although most access points won’t support more than four.
Wi-Fi 5 uses the same frequency as before, including adding the 40-Megahertz bonded channel. Wi-Fi 5 also adds 80 Megahertz channels and 160 Megahertz channels. You will notice there are only two channels at 160 Megahertz. Given how large this frequency range is, it could be difficult to use since it relies on the frequencies not being used by other devices. Keep in mind, the channel can’t be used if radar is detected in that frequency range.
MIMO requires channels of the same frequency width, since the channels need to keep in sync with each other. So, this is a consideration when using Wi-Fi. If you increase the frequency width, you increase the bandwidth, but this may cause other problems, such as MIMO not being able to be used or slower speeds due to other devices using part of the frequency range. Sometimes it is trial and error to get the settings right.
802.11ax (Wi-Fi 6)
Wi-Fi 6 was released in 2019, so it has been on the market long enough that new devices should support it. It has a maximum speed of 9 Gigabits per second, but keep in mind, this requires the right conditions with the right equipment.
In 2020, a revision was released which allows use of the 6 GHz range. The 6 GHz range is pretty similar to the 5 GHz range; however, a higher frequency does mean that it has slightly more bandwidth than the 5 GHz range, but the range is slightly less. The biggest advantage of the 6 GHz range is that it has fewer devices on it. Fewer devices in the range means it is less likely to get interference from others.
To further improve performance, Wi-Fi 6 adds Orthogonal Frequency Division Multiple Access or OFDMA. It gets rather technical how this works, but to put it in simple terms, OFDMA divides channels into sub-channels. Essentially, when data is transferred from the access point, multiple device data is transmitted all at once rather than each device having its data transmitted one at a time. It is kind of like carpooling or putting multiple packages on the back of a truck. Doing it this way is more efficient for networks with a lot of devices on them.
In The Real World
In the real world, I would purchase the newest Wi-Fi standard when costs allow. Wi-Fi 6 has good market adoption in some areas. You will still find cheap mobile devices on the market that use Wi-Fi 4. For a mobile device, Wi-Fi 4 is not too bad, speed wise, for surfing the internet and reading e-mails. It comes down to how much you want to pay and how much benefit it will give you. If, however, you are purchasing a wireless card or a Wi-Fi router, I would always try to get at least Wi-Fi 6. The cost difference should not be too much.
Access points are generally backward compatible. There are some access points that don’t support earlier standards, but that is not the norm. Devices using old standards can slow down other devices. Modern routers with multiple antennas will hopefully keep them separated.
There are a lot of factors to consider when using Wi-Fi. Hopefully your access point does a good job of managing them. I will now have a look at the settings on a Wi-Fi router so you can get an idea what settings you should be configuring.
Your Wi-Fi router will most likely have a different interface to this one, but I will show you the settings that apply to this video. It is not a bad idea to have a look at the settings on your wireless point at least once to see if it is configured for your needs.
This Wi-Fi router is dual band, so you can see at the top the two different SSIDs. I have named them Wi-Fi 2.4Ghz and Wi-Fi 5GHz to make them easy to understand which is which. You could give them the same name if you wish. Having different SSIDs means you can choose which frequency you want to connect to.
On this particular Wi-Fi router, there is a pulldown to determine if 2.4 GHz or 5 GHz settings are being configured. Below this is the SSID for the 2.4 GHz band. You are free to call this what you want.
Below this is the wireless mode. You will notice that this has “N only” or “Legacy”. Legacy being everything before Wi-Fi 4. Wi-Fi 4 was released in 2008, so any modern device should support it as a minimum. It is unlikely that you will have a device that requires legacy unless you are using a very old device. I would personally leave this setting on auto. I generally leave everything on auto and trust the Wi-Fi router to make good decisions. If the Wi-Fi router is not performing well or there are good reasons, I would then make changes.
There is an option to disable 11b. 11b was superseded in 2003 and was not very popular, so it is very unlikely any of your devices will require it. I would personally disable it. If you are setting up a public access point and you want everyone to have access, you may want to leave it enabled in case someone has a very old device and accessibility is more important than speed. Keep in mind that 11b has poor collision avoidance, or to put it another way, it does not work well with other protocols. Thus, on modern networks, it is recommended to disable it as it will slow down the other protocols.
Below this is the option to enable Wi-Fi 6. Currently it is disabled, which is why I like going through the settings. Sometimes the manufacturer of the Wi-Fi router will disable newer features for compatibility reasons. Some older devices may have problems if Wi-Fi 6 is enabled. I would personally enable it and, if there are problems, then disable it. Given this is a dual band router, you can always enable it on one frequency and disable it on the other.
Below this is the channel bandwidth. This router has the option to set it to 20 or 40 M Hz. As with the other options, I will just set this to use either 20 or 40 and then let the router set this option as appropriate. If you are setting up a company access point and the same devices always connect to it, you may want to consider changing this, but personally, unless there is a good reason, I would just leave it on the automatic setting.
The next setting is the control channel. You can see all the different channels you can configure. If you leave it on auto, the channel will automatically change as required. If you are in a building with a lot of different Wi-Fi points, you may want to select a channel that gives you good results. However, keep in mind that if someone later sets up a Wi-Fi access point, this channel may no longer be the best option. For this reason, I will set it to auto and trust the Wi-Fi router to make good decisions. If I find the Wi-Fi router is not making good decisions, I may set this channel manually.
You will also notice that this Wi-Fi router will tell you which channel is currently in use – here it is channel 4. I will now go up to the top and select 5 GHz. This will show the settings for the 5 GHz frequency. Your Wi-Fi router will most likely be different and may have this setting separate or it may have them combined together.
As before, there is an SSID that can be configured. It can be set to the same as the other SSID or different depending on your needs.
Below this is the wireless mode. You will notice the list has changed from those network standards that were supported for 2.4 GHz. If you have a network that only has particular devices connecting, for example, setting up an access point for a warehouse that only uses certain devices, you may want to configure this. Unless you have good reason to change it, I would recommend just leaving this on auto.
The next setting down enables or disables Wi-Fi 6. This is one of the reasons why I like to check the settings, because this setting is currently off. Enabling it can cause compatibility problems with some devices. Some devices may need updated drivers or firmware updates.
If your devices still do not work after applying updates, I would personally recommend disabling Wi-Fi 6 on the 2.4 GHz frequency and enabling it on the 5 GHz frequency. This allows older devices to connect to the 2.4 GHz frequency which they will most likely support. Your newer devices will still be able to connect to the 5 GHz frequency. If you are having problems like this, you may need to configure the SSIDs to different names to make sure the devices are separated.
Below this is the setting for the channel bandwidth. This can be configured so the Wi-Fi router selects the channel bandwidth automatically or you can select which one you wish to use. Again, I would leave this setting on automatic. If you set it to a high bandwidth and radar is detected in your area, this can dynamically reduce the number of channels available.
I could next set the channel if I wish; as before, unless you have good reason, I would leave this on automatic. You can see that currently the Wi-Fi router is using channel 44. Hopefully the Wi-Fi router makes some good decisions for you, but if it does not, you can always override specific settings.
End Screen
That concludes this video from ITFreeTraining on wireless standards. I hope this video has helped you understand the standards a little better. Until the next video from us, I would like to thank you for watching.
References
“The Official CompTIA A+ Core Study Guide (Exam 220-1101)” pages 145 to 150
“Picture: Truck” https://clipartix.com/truck-clipart-image-15063/
Credits
Trainer: Austin Mason http://ITFreeTraining.com
Voice Talent: HP Lewis http://hplewis.com
Quality Assurance: Brett Batson http://www.pbb-proofreading.uk