01_Introduct

8/2/2019 01_Introduct

1/20

Mobile

Comms.Systems

1

Mobile Communications

Systems

Luis M. Correia

Instituto Superior Tcnico

Technical University of LisbonPortugal


2/20

Mobile

Comms.Systems

2

Introduction


3/20

Mobile

Comms.Systems

3

Mobile communications services include:

paging;

cordless phone;

private mobile radio and trunking;

cellular communications; vehicular traffic information, control and

guidance;

wireless data and multimedia;

location based services;

wireless local area networks (WLANs).

Types of ServicesTySe (1/3)


4/20

Mobile

Comms.Systems

4

Types of Services

Services can grouped according to the type of link:

broadcast: information is sent from a centre,

being received by several users;

point-to-point: information is exchanged

between two users; point-to-multipoint: information is exchanged

between a user and a group of users.

TySe (2/3)


5/20

Mobile

Comms.Systems

5

Systems can be grouped according to the link:

two-way: ___ simplex: 1 channel

___ full duplex: 2 simultaneous

channels

___ half duplex: 2 alternatechannels

one-way : ___ base mobile

___ mobile base

Types of ServicesTySe (3/3)


6/20

Mobile

Comms.Systems

6

Frequency Bands

VLF telegraphy with submerged submarines.

LF long distance communications between ships

and shore stations.

MF medium distance communications for

terrestrial, maritime and aeronautical systems. HF long distance medium distance

communications for terrestrial, maritime and

aeronautical systems

FrBa (1/2)


7/20

Mobile

Comms.Systems

7

Frequency Bands

VHF short/medium distance terrestrial, maritime

and aeronautical systems, besides cordless phones

and paging.

UHF short distance cellular systems, WLANs,

and satellite systems.

SHF short distance systems are foreseen for this

band.

EHF very short distance systems will occupy thisband.

FrBa (2/2)


8/20

Mobile

Comms.Systems

8

Terrestrial Mobile Communications

Currently, the band [70, 2 200] MHz is used, due

to:

propagation characteristics;

type and size of antennas.

The trend is to use higher frequency bands in thefuture.

Antennas are usually dipoles, monopoles, helices,

patches, and printed elements:

isolated in mobile terminals;

in array configuration in base stations.

TeMC (1/2)


9/20

Mobile

Comms.Systems

9

Terrestrial Mobile Communications

In the VHF/UHF band, propagation is

characterised by being:

almost independent of polarisation and soil

electromagnetic properties;

essentially done via direct and reflected rays; influenced by the presence of obstacles;

almost insensitive to refraction by atmosphere;

basically limited by the radio-horizon;

basically independent of rain, gases and others.

TeMC (2/2)


10/20

Mobile

Comms.Systems10

Differences with Other Services

In fixed services:

one may chose the propagation path aiming at

avoiding problems;

directive antennas are used, placed for line-of-

sight (LoS); fading is not very important.

In broadcast:

communication is one way;

coverage is achieved by a small number of

transmitters;

receivers can be placed in an optimum location.

DiOS (1/1)


11/20

Mobile

Comms.Systems11

Cellular Systems EvolutionCeSE (1/3)

System Start CountryNAMTS 1978 JP

NMT 1981 NO, SE, FIAMPS 1983 USC 1985 DE

TACS 1985 UK GSM 1991 EUIS-94 1991 US

PDC 1995 JPcdmaOne 1996 USUMTS 2002 EU, JP

CDMA2000 2003 USLTE 2010 SE, NO


12/20

Mobile

Comms.Systems12


The 1st generation used analogue technology, and

allowed only voice communications.

The 2nd generation uses digital technology, and

allows data communications, although it has been

designed for voice.

The 3rd generation uses digital technology, and it

has been designed for data and multimedia

communications.

The 4th generation uses digital technology, has

been designed for multimedia communications,

and supplies very high data rates.


13/20

Mobile

Comms.Systems13


[Source: ANACOM]


14/20

Mobile

Comms.Systems14

Mobile Phones EvolutionMoPE (1/6)

[Source: Racal]


15/20

Mobile

Comms.Systems15


[Source: Racal]


16/20

Mobile

Comms.Systems16


[Source: Ericsson]


17/20

Mobile

Comms.Systems17


[Source: Manufacturers, Operators]

0

500

1 000

1 500

2 000

2 500

3 0003 500

Jan.

89

Jan.

90

Jan.

91

Jan.

92

Jan.

93

Jan.

94

Jan.

95

Jan.

96

Jan.

97

Jan.

98

Year

W

eig

ht[g]

0

500

1 000

1 500

2 000

2 500

3 000

3 5004 000

Price

[Euro]


18/20

Mobile

Comms.Systems18


[Source: Nokia]


19/20

Mobile

Comms.Systems19


[Source: Mobilemag]


20/20

Mobile

Comms.Systems20

Table of ContentsToC (1/1)

TySe - Types of Services

FrBa - Frequency Bands

TeMC - Terrestrial Mobile Communications

DiOS - Differences with Other Services

CeSE - Cellular Systems Evolution

MoPE - Mobile Phones Evolution

01_Introduct

Documents