Thuyết trình chủ đề mobile phone systems

MOBILE PHONE SYSTEM

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7140266 Vũ Hoàng Việt
7140264 Võ Thái Tuyến
7140255 Đỗ Duy Quốc
7140260 Nguyễn Hoàng Tín

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TOC

●History
●First generation (1G): Analog voice
●Second generation (2G): Digital voice
●Third generation (3G): Digital voice and data
●Fourth generation (4G): 3G + Mobile ultra-broadband Internet access

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Mobile Phone System

●Used for wide area voice and data communication.
●Sometimes called cellphones.
●Has 3 generations: 1G, 2G, 3G.

●Mobile phones should not be confused with cordless phones.

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Mobile Phone System
The first mobile system was devised in the U.S. by AT&T and mandated for the whole country by the FCC

Martin Cooper, a Motorola researcher and executive

(Source: Wikipedia)
( The prototype handheld phone used by Dr. Cooper

w

eighed 1.1 kg and measured 23 cm long, 13 cm deep and 4.45 cm wide. The prototype offered a talk time of just 30 minutes and took
10 hours to recharge.)


Mobile Phone System

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Usage and adoption in US vs Europe

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Several systems vs only one system.

Mixed phone number.
Prepaid mobile phone in Europe.

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First Generation – 1G (Analog Voice)
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Mobile radio telephones (maritime and military).

(Source: Wikipedia)
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First Generation – 1G (Analog Voice)
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In 1946, the first system for car-based telephones was set up in St. Louis.
(Push-to-talk systems).

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CB radio, taxis, and police cars often use this technology.

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First Generation – 1G (Analog Voice)

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In the 1960s, IMTS (Improved Mobile Telephone System) was installed.

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Use a high-powered (200-watt) transmitter

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Support 23 channels spread out from 150 MHz to 450 MHz.

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First Generation – 1G (Analog Voice)

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Advanced Mobile Phone System (AMPS) first installed in the United States in 1982.
A geographic region is divided up into cells (10 – 20 KM across).
An IMTS system 100 km across can have only one call on each frequency.
An AMPS system might have 100 10-km cells in the same area and be able to have 10 to 15 calls
on each frequency.


First Generation – 1G (Analog Voice)

(Source: Tanenbaum & Wetherall, Computer Network (5th edition - Prentice Hall)


First Generation – 1G (Analog Voice)

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The base station consists of a computer and transmitter / receiver connected to an antenna.
In a small system, all the base stations are connected to a single device called an MSC (Mobile Switching Center) or
MTSO (Mobile Telephone Switching Office)

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Handoff, takes about 300 msec.


First Generation – 1G (Analog Voice)

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AMPS uses FDM to separate the channels. (832 full duplex channels - Frequency Division Duplex)
832 simplex channels from 824 to 849 MHz are used for mobile to base station transmission.
832 simplex channels from 869 to 894 MHz are used for base station to mobile transmission.


First Generation – 1G (Analog Voice)

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Control channels (base to mobile) are used to manage the system.
Paging channels (base to mobile) alert mobile users to calls for them.
Access channels (bidirectional) are used for call setup and channel assignment.
Data channels (bidirectional) carry voice, fax, or data.


First Generation – 1G (Analog Voice)

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Call management:

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Registering
Making a call
Receiving a call


First Generation – 1G (Analog Voice)

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Call management
Registering (every 15 mins)
Scans a preprogrammed list of 21 control channels
Broadcasts its 32-bit serial number and 34-bit telephone number

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First Generation – 1G (Analog Voice)

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Call management

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Making a call

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Transmits the number to be called and its own identity on the access channel =>
base station => MSC

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MSC looks for an idle channel for the call => send back channel number on the

control channel.

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First Generation – 1G (Analog Voice)
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Call management

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Receiving a call

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All idle phones continuously listen to the paging channel.
When a call is placed to a mobile phone (fixed/mobile phone) packet is sent to the callee’s home MSC
to find out where it is.

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A packet is then sent to the base station in its current cell, which sends a broadcast on the paging
channel.

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2G

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Allowing voice signals to be digitized and compressed.
This in turn deters fraud and eavesdropping.
New services such as text messaging.

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CDMA

CDMA

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GSM
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at one time
850 MHz và 1900 MHz , 900 MHz và 1800 MHz ()
GSM: macro, micro, pico và femto
EDGE: ~3 GPRS.

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GSM

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HCM 2.000.000 km2, 10000
Frequency -> signal (850)

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