Chapter 7. Emerging Technologies
The preceding chapters have discussed the state of wireless communications
today with an emphasis on data communications. The wireless industry is
rapidly developing with significant changes in technology taking place every few
months. The ability to make use of even larger parts of the electromagnetic
spectrum for commercial applications is a direct result of the high levels of
integration and miniaturization of electronics. These advances in technology
have in turn generated new demands and expectations for applications that
would have been considered impossible a few years ago.
A major change which is impacting people′s working lives is the need for
mobility. Changes in working patterns mean that the traditional desk-bound job
is being superseded by working from home and the mobile office. People expect
to be able to access services from a number of different locations in order to be
as effective as possible in their jobs. The wired infrastructure is expensive to
maintain and even more expensive to install new services. Wireless
communications will allow additional services to be supplied to existing and new
locations. An example of this is seen in the new PCN services in Europe.
Families who would normally only have a single phone line in the house are
buying PCN phones to provide additional communications facilities at low cost.
PCN network operators are offering free calls in off peak periods and customers
are taking advantage of this to provide a second phone to the house (in some
cases just to allow the children to make long calls without tying up the main
phone, and without costing anything). In this situation, the mobility of a wireless
communications device is a secondary advantage. The main reason is to
provide alternative communications services at low cost. Working from home
can cause problems when there is a single phone for work use and office use. A
wireless device can solve this problem and ensure that someone may be
contacted on a single phone number regardless if they are working in a
traditional office or at home.
New applications are being developed which make use of technology which is
not yet available, but is certain to be there when it is needed. An example of
this is Intelligent Networking (see 7.5, “Intelligent Networks” on page 137). One
of the main driving forces behind these advances is the use of computer
technology and digital transmission techniques.
7.1 Digital Technology
We have seen how cellular telephony is being revolutionized by the use of digital
transmission methods. This creates a significant step forward in the radio
transmission of speech and ensures that there is no degradation of quality, no
matter how many times the signal is processed (amplified or converted),
providing that digital techniques are employed throughout the complete length of
the communications link. Unfortunately, although much of our land-based
network uses digital methods for trunking and long distance transmission, the
telephone connection to individual telephones is almost always analog today.
Large private corporations and public offices are slowly replacing their
telephone switches with new digital exchanges and thus enabling the capability
for an end-to-end digital connection. However, telephone switches are usually a
long-term investment (installed for 20 years or more), and so it will be some time
before digital communications will become ubiquitous in the commercial
Copyright IBM Corp. 1994, 1995 133