Why Wireless Data.pdf

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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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