Transcript History of Cell Phones

Cell Phones and Computers
Monica Leclerc
Joseph Fasino
Nicole Downs
History
Cellular: A type of wireless communication that is
most familiar to mobile phones users. It's called
'cellular' because the system uses many base
stations to divide a service area into multiple 'cells'.
Cellular calls are transferred from base station to
base station as a user travels from cell to cell.
(Bellis)
The First Model
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First concept introduced in 1947
Incorporated technology from car phones
Purely theoretical
No technology existed to support it
The FCC
• The Federal Communications Committee
• Queried by AT&T for allocation of radio
frequencies
• Supposed to motivate research
• Suggested business profit capability
• Granted limited amount
The Problem
• The FCC was too wary of the new
technology
• Only allocated enough to sustain 23
conversations in one cell area
• Not suitable for large profit
• Inhibited research and progress
1968
• FCC reconsiders
• “if the technology to build a better mobile
service works, we will increase the
frequencies allocation, freeing the
airwaves for more mobile phones”. (Bellis)
• AT&T and Bell Labs propose theories
• Still no existing technology
Dr. Martin Cooper
• Researcher for Motorola
• Credited with inventing the first cellular
phone
• 1973 made the first call to rival Joel Engel,
Head Researcher from Bell Labs
• Motorola first to use cell technology
without the use of an automobile
AT&T Follows Suit
• 1977 introduced their own patent
• 1978 tested in Chicago with a trial of over
2,000
Technology of the cell phone
How it works
• They operate between cells and switch
cells as a person moves around.
• When you make a call on your cell phone,
it is wirelessly linked to the telephone
network via these towers so your call can
be connected.
Towers
• Each tower, or base station,
covers a roughly circular area
called a cell
• This allows different base
stations to use the same
frequencies, or channels, for
communication links as long as
a sufficient distance separates
them. This is known as
frequency re-use, and allows
thousands or even hundreds of
thousands of mobile telephone
users in a metropolitan area to
share far fewer channels
Making a call
• Transmits the number along with a request for
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service signal.
It then transmits this information on the
strongest reverse control channel where the
MTSO checks the information and assigns it to a
voice channel.
The cell site will then open a voice channel and
transmit a SAT which is then locked onto the
mobile and transmitted back to the cell site.
The info is then confirmed and sends a mobile
message as either a busy signal or a ringback.
3 generations of mobile
technology:
1. Analog
2. Digital
3. Smart phones
Analog System
• The first generation of mobile technology
is the analog cellular system
• Increase in the number of available
channels
• The cell-phone carrier receives about 800
frequencies to use across a city.
• The carrier chops up the city into cells,
each cell is about 10 square miles and are
on a giant hexagon grid.
Cell Grid
• Each cell consists of a
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base tower through
which signals are sent
and received.
Each cell uses 1/7 of
the available channels
so its frequency is
unique and the
signals don’t collide.
2G Digital Transmission
• Increase in the number of available channels
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within a given bandwidth.
It compresses your voice into binary information
which allows 3-10 digital phones to occupy the
space of one single analog call.
Frequency shift keying sends data back and
forth over AMPS using 2 alternate frequencies,1s
and 0s, alternating rapidly between the two to
send digital information between the cell tower
and the phone.
They have a lot of processing power.
Sharing technologies 2G & 3G
• Frequency division multiple access (FDMA)
– Puts each call on a separate frequency.
• Time division multiple access (TDMA)
– Assigns each call a certain amount of time on
its designated frequency.
• Code division multiple access (CDMA)
– Gives each call it’s own unique code and
spreads it over the available frequencies
FDMA
TDMA
CDMA
3G Smart phones
• Intended for true multimedia use- referred to as
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smart phones
Smart phones are intended to allow you to use
other programs on the phone that you couldn’t
use with a standard phone.
Increased bandwidth and has transfer rates to
accommodate the internet.
It contains many cellular technologies but the 3
most common are: Code Division Multiple
Access, Wideband Code Division Multiple Access,
and Time-division Synchronous Code-division
Multiple Access.
Analog
Digital
Smart phone
Taking it apart
• Circuit board – brains
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of the phone
Antenna
Liquid Crystal Display
(LCD)
Keyboard
Microphone
Speaker
Battery
Circuit board
• Contains an analog-to-
digital and digital-toanalog conversion chip
which translates the
outgoing audio signal
from analog to digital
and the incoming signal
from digital back to
analog.
Front
Back
LCD, keypad, and other parts
• Thinner, lighter, use
less battery power
than other displays
Speaker,
microphone and
battery backups
Microprocessor & Flash memory
• The microprocessor deals with
command and control signaling
with the base station. It also
coordinates the functions of the
keyboard and display.
• The flash memory and ROM
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chips provide storage for the
operating system and
customizable phone features.
Some phones use internal
memory to store info while
others use the external memory
card.
Four Main Carriers
•Verizon Wireless
•T-Mobile
•Cingular
•Sprint/Nextel
Comparing Plans
Plan
Cost
Minutes
Overage
Cost
Nights &
Weekends
Extra
Verizon
Basic
$39.99
450
$0.45/
Per Min
Free 9pm
Nights &
Weekends
Mobile to
Mobile
T-Mobile
Basic
$29.99
300
$0.40/ Per
Min
Free
Weekends
None
T-Mobile
“MyFave”
$39.99
300
$0.40/ Per
Min
Free
Weekends
Free to 5
numbers
Basic
Cingular
$39.99
450
$0.45/ Per
Min
Basic Sprint
$29.99
200
$5 for 30
Min plus
$0.20 after
500 min
Free 7pm
Nights &
Weekends
None
Basic Nextel
$49.99
400
N/A
Free 9pm
Nights &
Weekends
Free Nextel
WalkieTalkie
Rollover
Mobile to
Mobile
Add-ons for Phones
• Text Messaging
• Multimedia
Messaging
• E-mail
• Internet
• Instant Messaging
• MP3 Player
• Maps
• News & Weather
• Custom Ring Tones
• Ring Back Tones
• Video Player