Mobile Networks Overview & 2G Standards Comparison

Mobile Networks
Overview &
2G Standards Comparison
Date
All rights reserved ©
2000, Alcatel, Paris.
Location, Date, page n° 2
Outline

I - Mobile Networks Overview

II - Radio Technologies

III - 2G Standards

IV - GSM Advantages over CDMA
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2000, Alcatel, Paris.
Location, Date, page n° 3
Cellular Networks
Omni-dire c tional
Unidire ctional
Se cto re d
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2000, Alcatel, Paris.
Location, Date, page n° 4
Cellular Networks History

1
s t
Generation: Analog Networks


1979 Chicago AMPS

1981 Sweden NMT

1985 United Kingdom TACS

2
nd
Generation: Digital Networks

1992 Europe GSM 900 / GSM 1800

1995 USA IS95 (CDMA)

3
rd
Generation: Federative Standards

2000 Europe UMTS

idem USA IMT 2000: EDGE + CDMA2000
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2000, Alcatel, Paris.
Location, Date, page n° 5
Types of Cells for
Different Applications
Satellite
Macro-Cell
Micro-Cell

Urban
In-building
Pico-Cell
Global
Rural
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2000, Alcatel, Paris.
Location, Date, page n° 6
Architecture of a GSM Network
Network Sub-System (NSS)
Base station Sub-System (BSS)
MSC/VLR
HLR/AuC
IN
e a s y 0 6
BSC
B
T
S
B
T
S
B
T
S
B
T
S
BSC
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2000, Alcatel, Paris.
Location, Date, page n° 7
Outline

I - Mobile Networks Overview

II - Radio Technologies

III - 2G Standards

IV - GSM Advantages over CDMA
All rights reserved ©
2000, Alcatel, Paris.
Location, Date, page n° 8
Air Interface Multiple Access Scheme
FDMA, TDMA & CDMA
Channel 1
Channel 2
Channel 3
Time
Frequency
FDMA
Time
Frequency
TDMA
Ch
1
Ch
2
Ch

3
Time
Frequency
CDMA
Code
Bandwidth Divis io n
into Fre que nc ie s
Freque ncy Divis io n
into Time S lo ts
Ps e udo -Rando m
Co de
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2000, Alcatel, Paris.
Location, Date, page n° 9
Frequency Division Multiple Access
FDMA
Frequency
Frequency
T
i
m
e
T
i
m
e
Power
Power
One User
One User

FDMA
FDMA

Each user is assigned a
slice of the RF spectrum

Applications

Analog Cellular

AMPS

NMT

TACS

Analog PMR

Analog Satellites
Bandwidth Divis ion into Frequencies
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2000, Alcatel, Paris.
Location, Date, page n° 10
Time Division Multiple Access
TDMA
Power
Power
Frequency
Frequency
T

i
m
e
T
i
m
e
U
s
e
r
U
s
e
r
TDMA
TDMA

Users share one RF carrier
on a time slot basis

Applications

Digital cellular

GSM,

D-AMPS

Satellite (VSAT)

Frequency Divis ion into Time Slots
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2000, Alcatel, Paris.
Location, Date, page n° 11
Code Division Multiple Access
CDMA
Frequency
Frequency
T
i
m
e
T
i
m
e
Power
Power
One User
One User
CDMA
CDMA
Ps eudo-Random Code Sequence

All users use the entire carrier
all of the time !!

“Spread Spectrum” technology

1 user = 1 Unique digital code


Other users = Noise

Applications

Digital Cellular (IS-95)

Satellite (Globalstar)
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2000, Alcatel, Paris.
Location, Date, page n° 12
Multiple Access Scheme
CDMA vs TDMA
Conversation 1
Conversation 2
Conversation 3
TDMA CDMA
Time
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2000, Alcatel, Paris.
Location, Date, page n° 13
The Cocktail Party Analogy 1/3

Partygoers = Cellular users

1-to-1 conversation = Com.

Room = Frequency
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2000, Alcatel, Paris.

Location, Date, page n° 14
The Cocktail Party Analogy 2/3
FDMA, TDMA vs CDMA
FDMA
TDMA CDMA