We rely on our wireless networks to provide connectivity for almost all of our computing devices. In this video, you’ll learn about infrared, near field communication, Bluetooth, and 802.11 wireless networks.
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There are many different ways to connect our mobile devices and computers without using any wires at all and in this video we’ll look at some of the standards for wireless connectivity. A wireless standard that’s been around for a long time is one that uses infrared. It’s a standard from the Infrared Data Association or IrDA.
This provided four megabits per second of speed, but it needed to be line-of-sight because it’s using an infrared connection that’s not able to go around corners. We’re able to get about three feet or meters worth of distance between the two devices. And you commonly see this used on older laptops, or printers, or cameras to be able to transfer information between those devices.
One of the latest short-range wireless technologies is NFC, stands for Near Field Communication. There’s three different speeds supported, a 106, 212 and 424 kilobits per second. And you can see the distance is a very short 10 centimeters, which is about four inches or less to send this communication.
Although these are relatively small speeds in a pretty small range of communication, these are perfect for doing things like paying with your mobile device. So instead of pulling out a credit card, you can simply tap your phone onto one of these payment terminals and now the NFC communication is transferred everything it needs to complete that transaction.
A very common wireless communication type on our mobile devices is Bluetooth. The Bluetooth radios are categorized into different classes. You may see a Class 1, a Class 2 or a Class 3 Bluetooth radio. Class 1 is really designed for industrial use. We really don’t see this on our mobile devices. It outputs a maximum power of 100 milliwatts and it will go about 100 meters as its range.
It’s much more common on our mobile devices to see a Class 2 which outputs about 2 and 1/2 milliwatts and the range is about 10 meters. For very specialized use, there is the Class 3 Bluetooth radio. This allows for a maximum power of one milliwatts and extends about one meter in distance.
There have been many versions of Bluetooth through the years. One of the very first was version 1.2 back in 1995 and allowed us to connect Bluetooth devices, disconnect it, and reconnect it very easily. Version 2.0 provided something called Enhanced Data Rate and you can see we were getting speeds of about three megabits per second with this 2.0 and 2.1 which included Enhanced Data Rate.
Version 3.0 of Bluetooth was called 3.0 plus HS. The HS was for high speed. It used Bluetooth to negotiate and establish the connection. But once the connection was up and running, it uses 802.11 to perform the actual file transfers and you can see we can get 24 megabits of throughput using 3.0 with high speed.
Version 4.0 of Bluetooth has speeds that are similar to 3.0. We get about 24 megabits of throughput, and one nice part about the version 4.0 is there’s a new low-power specification, so we can use our mobile devices for even longer.
One of the most common wireless types, of course, for a mobile devices is 802.11. And this is a summary of the 802.11 standards. We’ll be looking into more detail, in a future video, with these specific standards. 802.11 an 802.11b were some of the very first standards of 802.11. A used 5 GHz frequencies and 802.11b used 2.4 GHz frequencies. These allowed us a maximum theoretical throughput of 54 megabits per second for 802.11a and 11 megabits per second for 802.11b.
802.11g was effectively an upgrade to 802.11b using the same frequencies, but you can see it increased the speed up to 54 megabits per second. A much newer version of 802.11 is 802.11n. One of the newer standards of 802.11 is 802.11n. 802.11n allows us to use both 5 GHz and/or 2.4 GHz, if we’d like.
This allowed for four streams and provided us a total theoretical maximum throughput of 600 megabits per second. One of the latest standards for 802.11 really raises the bar. This is 802.11ac. It uses 5 GHz frequencies exclusively with eight allowable streams that go just over 866 megabits per second. We get a maximum theoretical throughput that approaches seven gigabits per second.