Why Wireless Data

Ch.13 - Why Wireless Data Communication? 1 To whom and for what? 2 Vertical Market 3 Users in Vertical Market 4 Horizontal Market 5 IP Everywhere 6 Internet Growth 7 Internet/Intranet access 8 Driving Forces - Terminals 9 Mobile Data Subscribers 10 The Future

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Ch.13 - Why Wireless Data Communication?

In the next few sections of the course we're going to look at Wireless Data Communications. Although this is currently a small market when compared to the global Internet, it is growing fast. First we'll look at why we have wireless communications. We'll look at the main markets for wireless communications -who uses it for what. In the next chapter we'll look at some general characteristics of wireless data networks, after which we'll take a more in depth look at one packet based, wireless system, GPRS. We then finish off with a look at some other wireless systems. The aim of this part of the course is to familiarise you with the terms and concepts used in wireless data communications, and to give you an idea of what it's being used for and why it is such an important market.

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Ch.13 - Why Wireless Data Communication?

The vertical market consists of applications developed specifically for wireless data networks. The interfaces and protocols used are not necessarily standardised, and applications are not easy to move to other networks. The vertical market can be split into two main areas - dispatch and telemetry. Dispatch usually means a central office sending messages to mobiles out in the field. For example, the most heavily loaded Mobitex network in the world is used for taxi dispatch in Singapore. There a central office sends out messages to drivers telling them where to pick up customers. Other dispatch applications include field service (Mobitex was developed with this application in mind), public safety and transport. Wireless networks allow a central office to keep track of users out in the field. Another important area in the vertical market is the telemetry market. In these cases there is an application that wishes to transmit data back to a central office. In many instances the application in the field is not even mobile. Metre reading is a good example of a telemetry application. For example, instead of sending an engineer round to your house every three months to read the gas metre, why not equip the metre with a radio modem? Every three months the modem transmits the metre reading to a central office. Obviously, the gas metre isn't mobile, so it's possible to equip it with, for example, a telephone line. But to give every gas metre a telephone line that is going to be used once every three months to send a few bytes of data is far too expensive, so radio modems can be used instead. In the States radio modems have been used in vending machines. The idea here is the same as that for metre reading - to save sending somebody out to a machine when it's not necessary. So, instead of having to send a technician out to a machine in some remote area every week,

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Ch.13 - Why Wireless Data Communication?

if the machine is equipped with a radio modem it can inform the central office when it is nearly empty and they can then send a technician out with refills. Field sales is another popular area in the vertical market. Here sales people can have direct access to the companies central database, thus allowing more efficient customer service.

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Ch.13 - Why Wireless Data Communication?

This graph shows the users in the vertical market. As you can see, transportation is the largest single group of users. The second largest group is field service -one of the oldest wireless data networks, Mobitex, was originally developed with this market in mind. The rest of the market is divided between other, smaller applications. Field sales, public safety (police networks for example), financial services and fixed data all claim less than 5% of the market.

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Ch.13 - Why Wireless Data Communication?

The horizontal market is characterised by the use of standard applications. The wireless network offers a standard protocol interface, for example TCP/IP. This means that users can buy off-the-shelf software, plug in their wireless modems and go. Because the network offers a standard interface, the software does not need to be specifically developed for the wireless network. This opens up a much broader market, as users are no longer constrained by the availability of specialist applications, so e-mail, database access, two-way paging and web browsing are all easily available. In this picture, point-of-sales is shown as being a part of the horizontal market. In actuality point-of-sale lies in a a grey area, as it relies on a series of standard and non-standard protocols.

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Ch.13 - Why Wireless Data Communication?

With this picture we can see the strength of IP - it's flexibility. If we imagine the hourglass as representative of three layers of the protocol stack, we can see why IP is so popular. IP is flexible enough to run on top of most protocols, so you can run IP on an Ethernet network, you can run IP on a X.25 network, you can run IP on a FDDI network or an ATM network. IP doesn't really care about the underlying network technology - it will run on all of them. Similarly, IP will support lots of different services. So you can run your e-mail software on top of IP, you can surf the web, you can read Usenet and so on. IP is flexible enough to offer all these services. This is the key to IP's success - it's flexibility. It will happily run on top lots of different networks and will happily support lots of different services. This is the beauty of IP.

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Ch.13 - Why Wireless Data Communication?

Almost everybody has seen a graph like this. It's a graph that shows how the Internet has grown over the last few years. The figures on the vertical axis are open to debate - it's actually impossible to count the number of Internet users. The point here is that the growth is exponential - more and more people are using the 'net everyday. When will this growth stop? Well, that's very hard to say. If the number of users continues to increase at current rate, by the year 2003, the number of Internet users will be greater than the population of this planet! Obviously, this isn't going to happen, but it just illustrates the rapid growth the 'net is going through right now.

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Ch.13 - Why Wireless Data Communication?

We use the internet as an access tool for different services, for example e-mail, web browsing and newsgroups. But how do we access the internet itself? Well, this is done in many different ways. You can use a normal dial-up modem, a satellite access system, an IR LAN, ISDN or the cable TV network. There are lots of different ways to connect yourself to the internet (or the corporate intranet), and there are pros and cons associated with each. However, the single, most flexible method is, by a long way, the use of a Public Land Mobile Network, or PLMN. Only a PLMN can give you the ability to access the internet from wherever you are, and only a PLMN can give you this access while you are mobile. This is why PLMNs are becoming so important. When you're at home, there are several different access technologies to choose from. Similarly, when you're at work, there are several possible methods of connecting to the 'net. But when you're out driving your car, the only way of accessing on-line information is via a PLMN.

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Ch.13 - Why Wireless Data Communication?

What is driving forward wireless data? Well, there are several important factors. One of the most important is the advent of smaller and more powerful portable computers. These machines mean that people can be much more mobile than in the past. A computer on its own is a powerful tool, but a computer attached to a network is even more powerful. So wireless users wish to exploit the full power of their laptops by connecting them to networks. Another force pushing the uptake of wireless communications is the Personal Digital Assistant or PDA such as the Apple Newton, US Robotics PalmPilot or the Psion. These small, handheld devices were initially little more than electronic diaries, but with the development of more powerful processors they have evolved into sophisticated machines in their own right, capable of reading and sending e-mail, faxes and surfing the web. These devices are becoming more and more popular due to their low price and high functionality. Connection to the internet or the intranet improves their usefulness. The improvements made in radio modem technology are also important in the market place. When Mobitex first came into commercial use in 1986 the radio equipment required was huge - it took up a significant part of a car's boot. It was mobile, but only if you had a car, there was no way in the world that you could use it in hand held terminals. Mobitex modems are now available on PC Cards, which are the size of a credit card and about a centimetre thick - a big improvement on the old technology. So now it is feasible to use one of these modems in a portable PC or PDA. Of course, the decrease in cost of all these items and the wireless data services means that they are becoming available to a greater portion of the market which in turn means a larger subscriber base.

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Ch.13 - Why Wireless Data Communication?

This graph shows how the number of wireless data subscribers is expected to increase in the future. The growth is slower than that of the internet but is still exponential. By building systems with standard interfaces and therefore opening up the horizontal market, it's hoped that the startling growth experienced by the Internet can be mimicked in the wireless data arena. More subscribers means more radio modems and network infrastructure is needed which, means more money for those companies that build such equipment.

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Ch.13 - Why Wireless Data Communication?

What's going to happen in the future is very hard to say. Bernt Ericsson, Ericsson's research manager, has talked about wireless multi-media application that would allow two-way, wireless video conferencing. Telia, Sweden's state owned PSTN operator have a vision of wireless multi-media communications at the cost of today's telephone calls. In a similar vein, Ericsson are currently involved in Sweden's largest ever research project to deliver a wireless multi-media network with a bit rate of 10 Mbps by the year 2005. Wireless multi-media offering high bit rate communication is certainly needed in the future current wireless networks have the technology to deliver data to users, but they all lack one thing - sufficient bandwidth.

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