APPENDIX 10: MOBILE PHONES
1. Future demands for microprocessing will increasingly
be for embedded applications — that is, dedicated and often
very sophisticated microprocessing technology operating products
in ways that are generally invisible to the user. A good example
of an embedded application is the mobile phone, the development
of which over the last two decades is outlined below.
A brief history of mobile phones
2. The first generation analogue mobile phone
system was introduced in the United Kingdom in 1985, and was called
Total Access Communication Technology (TACS). A typical early
phone weighed around 5 kg, cost several thousand pounds and had
a battery life of less than a day (or one hour's talk time). As
this was an analogue system, rather than digital, phones did not
require a Digital Signal Processor (DSP) chip. However, the first
single-chip DSP had been produced in the late 1970s, making a
fully digital system economically viable.
3. In Europe, a group of 26 national phone companies
began developing a digital standard in 1982. Agreed in 1991, the
Global System for Mobile communications (GSM) second generation
standard was introduced in the United Kingdom in 1992. This standard
is used by current UK mobile phones and allows text and data transmission
as well as simple voice telephony. By March 2002 there were nearly
700 million GSM customers world-wide[125].
Early GSM phones typically weighed 500g and had around 12 hours
of standby battery life. Today, they weigh as little as 60g, have
standby times of up to 10 days and talk times of up to five hours.
4. The next few years will see the introduction
of third generation (3G) mobile phones. These will allow higher
data rates than GSM, so users can more easily access internet
pages or send photographs using their mobile phones. The first
3G networks started in Japan and the Isle of Man in late 2001.
3G poses new challenges for mobile phone processor design, in
order to meet these higher data rates and increased functionality
while remaining low cost and low power.
5. Current mobile phones typically contain two
processors. A DSP deals with applications such as extracting digitally
coded speech from the signal received by the phone and decoding
it. A RISC processor (such as those developed by ARM) manages
the interfaces with the outside world, including interacting with
the mobile phone network and controlling the screen and key pad.
These two processors may be integrated onto a single chip.
Points to note
6. A number of useful points can be illustrated
by mobile phones and their use of microprocessors.
a. It is difficult to predict the future. Nearly
75% of the UK adult population now own a mobile phone[126]
and a large proportion of these include embedded processors licensed
by ARM, a British company. Twenty years ago, it would have been
difficult to predict the growth of the mobile phone market, let
alone the major role the United Kingdom would play in embedded
processors. Even on shorter time scales, predictions are difficult.
For example, in April 2000, the Stewart Report[127]
suggested that the number of UK mobile phone subscribers might
rise to 45 million within 5 years. This figure was actually reached
by early 2002[128].
Similarly, the rise in text messaging was entirely unexpected
— but over a billion text messages are now sent each month
in the United Kingdom[129].
b. Mobile phones show how processor requirements
vary depending on their application. Their processors must operate
at low power (for longer battery life), be small and low cost.
Successful embedded processors, therefore, are not necessarily
those with the greatest processor speed but those that balance
these requirements.
c. They are a mass market product. So, although
embedded processors may not be used for cutting-edge research
on specialist supercomputers, they are required in vast numbers
for an increasing array of day to day applications. It is these
high-volume products which will have most impact on the economy.
d. They illustrate how developments in the market
can be facilitated by, but not necessarily driven by, technology.
The rise of second generation mobile phones in Europe is often
attributed to European regulation introducing the GSM standard
across the continent, rather than specific technological or market
attributes.
e. Finally, mobile phones demonstrate the importance
of pleasing the customer. Although mobile phones for voice and
text are extremely popular, data services (using Wireless Application
Protocol or WAP technology) have been considerably less successful
than predicted by operators. Such issues will become more significant
with the next (third) generation of mobile phones, which will
allow mobile internet access. UK operators paid £22 bn
for licences to use the radio spectrum for these 3G mobile phones,
but it remains unclear how popular such services are likely to
be — and hence, how and over what time scale this investment
is to be recouped.
Europe/US differences
7. It is worth noting that the development of
mobile telephony is more advanced in Europe than in the US. This
is the result of interacting factors. The early US lead led to
substantial investment in first generation analogue networks using
a wider range of frequencies than in Europe. The demand for better
services that would attract investment in improved infrastructure
is, however, constrained by US regulatory requirements which may
lead to the person being called bearing a charge for receiving
the call (as for international calls within Europe). Consequently,
pagers are still widely used in the US[130]
where users tend to switch on their mobile phones only when they
want to make an outgoing call.
125 GSM Association. Back
126
Oftel, Consumers' use of mobile telephony Q8 February 2002. Back
127
Mobile Phones and Health, Independent Expert Group on Mobile
Phones, Chairman Sir William Stewart. Back
128
Oftel Mobile Market Update, Q4 2001/02 (January to March 2002). Back
129
Oftel Mobile Market Update, Q4 2001/02 (January to March 2002). Back
130
Unlike Europe, where they have been largely superseded by mobile
phones. Back
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