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Gabriel Maci Fernndez ([email protected])

http://ceres.ugr.es/~gmacia

08/07/2009

University of Granada (Spain) 1

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GabrielMaciFernndez2009

UniversityofGranada(Spain)

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Mobile Networks

Traffic scenarios explained

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Some questions

How is it possible to localize a mobilephone in a network?

How does the number portability work?

How can the network check my prepaidbalance?

Why emergency numbers appear at mycity?

How does roaming work?

How are SMS transferred through thenetwork?

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Index

PSTN architecture overview

Call establishment in PSTN.

Mobile Network architecture

Traffic scenarios in mobile networks

Location update

Mobile terminating call (MTC)

Intelligent network scenarios.

Roaming.

SMS scenarios

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PSTN architecture

Switching

center subscriber

Last mile

Access network

Core Network

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PSTN calls

Key aspects:Number A, number B

Signaling concept

B number routing tables Addressing plan

B number prefix next hop

Initial address message (IAM)

A number

B number

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Mobile Network Architecture

Key concepts:

IMSI is in SIM card, not MSISDN

HLR

Relates IMSIMSISDN (number B)

Keeps track of position of MS.

BTS

BSC

MSC/VLR

HLR

MSBTS

MSC/VLR

MSC/VLR

BSC

MS

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Location update

Concept of LA.

Types of LU:Periodic

Change of LA

Switch on / off

BTS

BSC

MSC/VLR

HLR

MSBTS

MSC/VLR

MSC/VLR

BSC

MS

IMSI-LAI

IMSI-VLR

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Mobile call

Problems:MSCs do not know MS position

Solution: MSCs should ask HLR about MS

location SRI (Send Routing Info).

Routing tables are static and should route to

MS whatever position it has.

Solution: use of fixed numbers associated to

MSCs which are temporarily assigned to MS

MSRN (MS roaming number).

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Mobile Call

BTS

BSCMSC/VLR

HLR

MSBTS

MSC/VLR

MSC/VLR

BSC

MS

B IMSI

IMSI - VLR

MSRN IMSIHowto

route to B?

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Intelligent network

Some examples of use:

Emergency numbers that depends on

location

Local number portability

Dynamic selection of destination

Closed user groupsPrepaid services balance check

Special tariffs

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Intelligent network

BTS

BSC

MSC/VLR

HLR

MSBTS

MSC/VLR

MSC/VLR

BSC

MS

TMN Network

SCP / SDP

2222+B

B-NumberTable

----------------------

1111 Vodafone

2222 TMN

IDP(B,

OTHER)

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Roaming

Home network vs visited

network

Roaming agreements

Brief process

Tariffs

HPMN

HLR

VPMN

MSC

roamer

1

2

3

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Short messages service (SMS)SMS center: SMSC (preconfigured in MS)

SMS originated and SMS terminatedHLR notification to SMSC

BTS

BSC

MSC/VLR

MSBTS

MSC/VLR

MSC/VLR

BSC

MS

SMSC

HLR

MT-ForwardSM

SM delivery

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Thanks for your attention

Any questions?

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