Mobile Communication Networks

Mobile networks differ from fixed networks in that the “last mile” (or the connection
to the user) is based on radio transmission techniques. This wireless service
gives the user the added benefit of mobility in the local area or wider area, depending
on the nature of the network.

Background to Mobile Radio
Wireless communication, either as part of a fixed network to extend the communications
without the need to install physical wires or as the connection to the user,
has been a goal ever since the advent of long-distance communications. Providing
a wireless connection to the user involves overcoming a large number of problems,
not the least of which is the size of the radio equipment that the user would be
expected to carry around.

Mobile radio systems have been around almost since the development of radio
technologies. One of the first installed mobile radio services was in the 1920s by the
police in Detroit. Mobile, in this case, meant that the radio equipment was small
enough to carry around in a vehicle. Early systems like this tended to be one-way
radio. It was not until the technology was pushed forward by World Wars I and II
that two-way radio began to emerge. Then the development of commercial radio
systems began.

Private Mobile Radio (PMR)
Mobile radio service used to be the preserve of military and commercial organizations.
The nature of the service was also very different from the telephone-style
service we expect today. However, an important element of modern radio systems
reflects the older style of service. Today we refer to these systems as Private or Public
Access Mobile Radio (PMR/PAMR).

Typical uses include emergency services, courier/delivery, and utilities and
dispatching services. The nature of this communication is point-to-multipoint or
group working (Figure 1.10). Interestingly, the public cellular operators are beginning
to offer similar services as value-added services on their networks.

Cellular Radio
Advances in technology and radio spectrum management have led to the development
of “cellular” radio networks, allowing the networks to support many users
over a wide area. Cellular refers only to the method of using the radio spectrum
available (Figure 1.11). Many different radio technologies can use cellular deployment
of radio channels. However, we often use the term “cellular” to mean a mobile
phone network such as GSM or cdmaOne.

Analog Mobile Networks
The first mobile phone networks began to appear in the latter part of the 1970s.
These systems were analog and supported a very limited service. Analog networks
do not naturally support data transmission. Modems could be purchased to allow
users to move data or send faxes, but this was expensive and slow. The handsets
were often bulky and had poor battery life (Figure 1.12). However, during the
1980s, many advances in all aspects of mobile phone technology meant that handsets
became smaller and more reliable, and battery life also improved.