Overview of Wireless Communications
1. Overview of Wireless Communications
Now, in this module, we're going to talk about some of the history of wireless communications. We'll look at some of the different standards, some of the regulatory agencies like the FCC, the ITUC, and the IETF. The ISOC hierarchy, the WiFi Alliance, the I Triple Believe, the ISO, and however many other acronyms you think I can put out there for you We'll also discuss the hierarchical model of our networks and where wireless access points fit in, as well as some of the differences between Karen signals and some of the fundamentals of communications.
2. Overview of Wireless History
So wireless communications, believe it or not, have been around since the 19th century. I know that seems like a long time ago. because it was. But we had a lot of scientists who were out there. People like Tesla and some others were experimenting with wireless communications. And they were successful at some of those types of communications. But all was not well. as it evolved. It wasn't until about the 1970s that the state of Hawaii actually had wireless communications that they were using to be able to transmit information between the islands. Now, the medium that they used—they called it Aloha—makes sense. It was Hawaii, and it operated at 400 MHz, which is certainly not the frequency range we're using today. In the 1990s, this again moved forward in our history. We saw commercial wireless start to take off, operating in the 900 MHz range. Basically, things like cordless telephones If you even remember the day when we actually had telephones that were attached somewhere to a jack in the wall of the house, But that and some other kids' toys—wireless toys—began in the nineties, and that was a common range that was being used.
3. Standards Part1
Now. the International Telecommunications Union. radio communications sector. big name for them. The Itur and other local entities like the Federal Communications Commission started setting the rules for what a user could and couldn't do with a radio transmitter. Now, these organisations manage and regulate the frequencies that we can use with their licenced or unlicensed power levels and the types of transmissions or the methods that we use for sending information. They are also working together to help us guide the growth and expansion of what's being used by today's wireless users. So it's really kind of a big area. There are a lot of companies and a lot of government agencies, not just in the United States but also in most of the countries around the world. and you'll see that there are some differences. If you were to travel, you might see a different number of channels being used at different frequencies; maybe a different power level is allowed. So it's important for vendors to be able to work with these different agencies to figure out how to build and create their products for the countries in which they are selling this information or the actual equipment, not the information.
4. Standards Part2
Now, the IEEE, the Institute of Electrical and Electronic Engineers, is the one that's creating the standards for compatibility and coexistence between networking equipment. Now, this group of people is, you know, several hundred people in this organization. And the idea is that they're not building the actual equipment, but rather creating the guidelines for how these different pieces of equipment from different vendors should work. So if you, say, have an access point from one location or one company, and you bought a laptop that has a wireless card built by another organization, how do we know that they're supposed to work together? And so that's what the IEEE standards are designed to do: be able to make that type of computer work. But it still has to fall inside the guidelines set by the FCC.
5. Standards Part3
the Internet Engineering Task Force. The IETF is the one that creates Internet standards. Again, they create standards. They're not creating the actual product. These standards are designed to be integrated into the wireless networking and security protocols and standards that we use for WiFi communications. Another group, the WiFi Alliance, is the one that's going to perform certification testing to make sure that the actual equipment by the vendors, whatever wireless networking equipment they use, is conforming to the IEEE standards of 800 and 211 when it comes to the different types of communication guidelines for wireless local area networks.
6. Standards Part4
The International Standards Organization designed what they called the OSI model. the open system interconnect. And again, it was guidelines for a way to help us know how technologies can talk to each other. So when we're taking a look at the OSI model We have to remember that we are still going to. more than likely. when we're creating these wireless networks. have to be involved with the IP protocol for the network layer and the different types of transport protocols. We are facilitating these packets so they can go from one host to another over a combination of wireless and wired networks. So as the administrator, you must be familiar with layers three and four. When you think about what we're doing, this is my picture of an access point. When we think about the actual wireless radio frequency, that points us here at the physical layer. That's instead of a copper wire or a fibre cable. We are sending radio frequencies to represent the medium at which we're transmitting at. And also, we have to have a way of doing communications that we'll talk more about at layer two with the data link player. Now. What's important about the OSI model is that the whole goal was to be able to say Hey. Look. We have to be able to have what they call PDUs. the ability for one layer to talk to the layer above it and the layer below it. meaning that it doesn't matter what we use in the physical realm. As long as whatever technology is capable of working at the data link layer, whatever's at the data link layer can work at the network layer. In fact, it was designed again as a model so that we could just rip any one of these layers out and replace it with a new layer. As an example, in the network layer, we've been focusing on IP version four for a very long time, and then suddenly we ripped that out and now put in IP version six. There is no problem at all with IP version six, as long as you can talk to the transport layer and the data link layer. That was the beauty of having an open model rather than having companies create their own protocols that were essentially proprietary to them. This was designed with open standards for any vendor creating this type of equipment.
7. The FCC Part1
Now, the FCC was established by the Communications Act of 1934. Now think about what's really happening. We did a lot with radio back in 1934, obviously a lot of radio shows and families watching or listening to the radio at night. So the FCC obviously has grown since then with what they are responsible for, and they are responsible for regulating any interstate and international communications that are done by radio or television, over a wire, by satellite, by cable, or any type of electronic communication. They also regulate the licenced spectrum and the unlicensed spectrum. Now, when I say licenced spectrum, if you think about your AM and FM radio channels, obviously those are licenced to companies that are broadcasting on those stations. And part of the reason for the licencing is to make sure that we don't have different radio stations trying to compete on the same band and cause interference. So there's a big reason why there needs to be a licence for that. The unlicensed spectrum is that which does not require a license. But the downside is that since nobody has to get a licence to use that medium, we can have a lot of different products that can interfere. As an example, if you're in your office, you have WiFi. What you're going to notice is that as you get close to, let's say, the kitchen or the cafeteria, things like the microwave are going to cause interference because they're using some of the same frequencies, and that becomes a bit of a problem. So we do have the issue, and we'll talk more about it when we get into these communications about having other devices or other types of technology basically step on your data signal within your location. And so that's probably the downside when it comes to using an unlicensed medium.
8. The FCC Part2
Now, when we talk about any of the communications, any of the frequencies, licenced or unlicensed, the FCC still has regulations that we have to abide by. Now. I know I just said "unlicensed. Anyone can use it. But we still have to deal with the FC FCC rules, such as the frequency that we're using and the bandwidth information, something we're going to talk a lot about and force you to do a little bit of math to determine the maximum power of the intentional radiator. Well, basically the antenna or the equipment But we'll get into those and the maximum, which they call EIRP or the equivalent isotropically radiated power. So, believe it or not, there is a limit to how much power we can use for communications with your access points. And technically, we could communicate if we had enough power over many miles—hundreds of miles or more. just like you see with things. again, like radio stations. But we don't do that in our office environment, again because of other regulations from the FCC. and we'll talk more still about the power calculation. And of course, they also regulate whether equipment is ready for indoor or outdoor use. And also, as I just talked about with these radio stations as an example, the spectrum sharing rules So all of that is licenced or regulated by the FCC. Bye.
9. ITU-R
Now the Itur is basically, as I said before, the International Telecommunications Union radio communications sector, a big name for a company or for an organization. Anyway, the United Nations has tasked that organisation, the Itur, with global spectrum management. Now, as I previously stated, the types of areas are very important to us because each region of the world will have some of its own regulations. And so this group is trying to work with them. As an example, they have Region A, which is the Americas. And we would look at something like the InterAmerican Telecommunications Commission, which they refer to as "the organisation that works with," remembering that there's more to the Americas than just the United States. I mean, just in North America, you have Canada, you have Mexico, and other countries. as you go further south. Western Europe. They have Region B anyway, and they use the Western Europe-European Postal and Telecommunications Administrations. They call it CEPT. And again, different countries. Regency is in Eastern Europe. And I won't go through and tell you all of the different names. You can certainly look at that as you go through this course. Region D is the African area, which is interesting because I did some work recently and for six months I lived down in Kenya. And so I got to see a little bit more about how the regulations and laws are a little bit different there than they are in other regions of the world. And then of course, the Asia Pacific, which would include Asia and Australia's telecommunications, is what they call the APT. The United Nations has an Oregon organisation that they're working with that is breaking down the different regions of the world and trying to work out how wireless communications should be used in those different parts of the world.
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