Since the advent of telecommunications, wires ie. copper, coax and more recently fibre optic,
have traditionally provided the link between the terminal equipment and the network. But
the wires dominance in this area is coming to an end. Economic imperatives and emerging
technologies are opening the door for wireless solutions.
The term "wireless" refers to a communications system in which electromagnetic waves carry the
signal over part or all of the path.
Early experimenters in electromagnetic physics dreamed of building a so-called wireless
telegraph. The first wireless telegraph transmitters went on the air in the early years of the
20th century. Later, as amplitude modulation (AM) made it possible to transmit voices and
music via wireless, the medium came to be called radio. With the advent of television, facsimile,
data communication, and the effective use of a larger portion of the electromagnetic spectrum,
the original term has been brought to life again.
Common examples of wireless equipment in use today include the Global Positioning System
(GPS), cellular phones and pagers and two-way radios. An increasing number of companies and
organizations are using wireless local area networks (LANs). Wireless transceivers are available
for connection to portable and notebook computers, allowing Internet access in selected cities
without the need to locate a telephone jack. Eventually, it will be possible to link any computer
to the Internet via satellite, no matter where in the world the computer might be located.
This essay attempts to visit a number of wireless data communications systems categorised by the
service they provide and how they provide it.
Chapter 1 - Wireless LANS {WLANS},
deals with wireless technologies such as Infra
Red {IR} and Radio Frequency {RF} and how they can be applied to Local Area Network
{LAN} applications.
Chapter 2 - Wireless Infrared,
discusses Infrared technology, how it works and where it is used.
Chapter 3 - Analog Cellular Systems,
discusses the original mobile telephone system and the
problems it poses to data communications.
Chapter 4 - Digital Cellular Systems,
discusses some of the more modern cellular mobile
systems such as GSM and the emerging new access method - Code Devision Multiple Access {CDMA}.
Chapter 5 - Satellite Systems,
deals with Global Satellite Coverage and some of the
systems being developed which hope to provide this service.
