tec Tip Videos

Wireless N Technology

Nathan explains some of the factors involved with Wireless N technology.


Transcription

Hello and thank you for joining us again today. Today we're going to be talking about Wireless N technology. While Wireless N has been around for awhile, actually I have the date written up here, since 2009. In those couple of years that we've had it and been using it every day, there's still a lot of folks who are a little confused or maybe see it as a bit of a mystery on how it works and maybe what kind of benefits that we can expect to see from it.

I wanted to take a few moments today to just sort of explain things, lay it out. Like I said, since 2009 is when Wireless N was ratified, since then we've been able to reap the benefits of having that extra speed. One of the things that I have on my list is it includes A and G, this is something that I've actually run into a lot with our customers is that they believe that N is a new letter in the spectrum here and while it is, while there is A, you'll see A, B, G and N listed together. N really encompasses sort of a revision or a refreshing of the old A and G standard and getting more speed and more bandwidth from those standards. A and G are both sort of revitalized and used in a different way to make sure that we have a lot more bandwidth.

Six hundred MB, I wrote this down because this is one of the big numbers you'll see associated with what Wireless N. Sometimes, you'll see 450, sometimes you'll see 300. A lot of times it depends on the manufacturer, the platform you're talking about but how do you get this much bandwidth. We're going to talk a little bit about that later but I just wanted to throw that down here that this is kind of one of those numbers that you're going to see associated with Wireless N.

Then kind of the big one is how does all of this work together, well I focused more on this word and then, this word a little bit as well, but MIMO, I guess is a word, it stands for multiple input, multiple output and what does that mean.

It's really important when you're explaining Wireless N in that through the use of multiple radios and through also streams, which we'll get into, you can increase the bandwidth of the already preexisting standards of A and G. Instead of just having a single A radio, a single G radio, you'll have multiple radios and multiple antennas that can add to that speed or that bandwidth that's available.

Like I said, we're going to talk a little bit about streams and I wanted to explain this. Streams may be something that you're going to hear when you're talking to an engineer or even when you're reading an documentation on Wireless N. Streams is a popular word used. In addition to channels is another thing. This is kind of crude drawing, I'm famous for crude drawings on what streams is.

With legacy technology with your Wireless A and G, you had one stream, right here. if you were to split this down the middle you'd have two streams per channel, 20 MHz channels. That was the way wireless always worked but through MIMO and through using multiple streams, we now add more streams, expanding the initial 20 MHz channel to two and then now with Wireless N having two channels of 20 MHz which gives us four streams.

If you want to think of this as a highway, if all the cars were down on this one road, okay we're used to going that speed or having that much room on the road to move around or to move that much traffic through at a time. If you were then to expand that single road to a four lane highway, how much more traffic could you get through. That's really all that streams is and how it relates back to MIMO.

All right so the final thing that I really wanted to share with you today is what these numbers mean and I've been asked this several times. A lot of times when you look at things, Cisco Access Points or anybody's access points really, you're going to see these numbers sort of set up in this configuration so you'll see, "Well hey this access point is a 2 by 2 or a 2 by 3." What does that mean? What does that there? Is it just a math equation? No, thank God. What is it?

This is really all it is. The initial number is your transmit antennas, how many transmit antennas will it use. The secondary number, the 3 here in this case, are the the receive antennas and then how many streams is the final number. If you had an access point that was rated in this fashion it would be 2 transmit with 2 receive at a max using 2 streams. They would refer it as a 2 by 3 probably for short. Then they probably would tell you later in the documentation that it was utilizing 2 streams.

Now why does this matter? When we talked about the beginning, 600 MB per second as a pie in the sky number, where you'd achieve any of that? It's these numbers become very important because not only do they matter on the access point side which is what we're all trying to connect to in the office or at McDonald's or wherever you are but it also matters on your client side so your cellphones, your iPads, your laptops, what are they rated at.

A lot of devices are, I'd say most cellphones really are probably 1 by 1 because if they were 2 by 3, the batteries would last about 10 minutes which is a total guess but you get what I'm saying. If my cellphone is only a 1 by 1, am I really going to take advantage of all of this. No. My cellphone, can it connect to N Wireless? Yes. Is it really going to get that full fruitful or that full benefit of what N is bringing to the table? No. It's going to see 600 MB per second necessarily.

Are there laptops or other devices that are better? Absolutely. In fact, there's some laptops out there that are rated 3 by 3 and have multi-streams and can really take advantage of all that wireless has to offer.

Hopefully, you were able to learn something today. Hope this was helpful and I wanted to just highlight this stream of numbers again. I'm going to give it a red smiley face because it's a little confused because while it looks like a math problem it's not. I do appreciate you spending some time with us today.