O2 FLT E22, User Manual

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Notes
50
How mobile phones work
Your mobile phone is a radio transmitter, basically no
different from any other two-way radio system. The
ingenuity of the mobile system lies in the splitting of
the broadcasting environment into a grid of relatively
small cells
with
low-power
transmitters, hence the
name “cellular phone”.
This cellular approach to radio communication allows
for extensive
frequency reuse
so that millions of
people can use their mobile phones simultaneously
although the number of frequencies is limited. Non-
adjacent cells can simply use the same frequencies
without risk of interference (see illustration). The
broadcasting grid is commonly illustrated as hexagons,
typically 10 square miles in area with the base station
in the centre.
[celler_sender.tif]
Your mobile phone is in constant contact with the
nearest base station. As you move from cell to cell,
e.g. while driving in your car, the base station you are
approaching takes over when you are within reach. This
happens within split seconds without your noticing it.
All you experience is a stable and clear connection.
O2 provides UK network coverage in excess of
99 percent. However, in rare occasions you may
experience diffi culties in maintaining the connection.
This happens if the radio signal is blocked by obstacles
such as high trees, hills or buildings, or if you are inside
a heavily reinforced concrete building.
Seek higher ground to remedy the situation. If you are
inside a building, try moving towards a window.
Power consumption
The battery life is infl uenced by the distance between
your phone and the nearest base station, and the
terrain obstacles in between. If line of sight to the base
station is blocked, the phone - whether in idle or in
conversation - will respond by increasing transmission
strength. This will also increase power consumption.
Following industry praxis, the average battery life
stated in the Technical Data is based on a situation
where the phone is left untouched, fully charged and
with a free line of sight to the base station.
The vocabulary
The mobile world has its own vocabulary that can be
quite confusing for the layman. We have listed some of
the most commonly used abbreviations and acronyms
below for your convenience.
APN.
APN stands for Access Point Name and is basically
an URL address on the Mobile Internet.
Digital.
Early cellular phones relied on analogue
systems. Analogue radio systems transmit the voice
signal in its original form, whereas digital technology
transforms the microphone signal into number
sequences (digits) and transmit these. When received,
the digital signal is decoded so that you can hear
the sender’s voice. Digital signals do not degrade in
quality as long as the data is received, and they can be
compressed to take up less memory.
Cache.
During online operations, the phone will store