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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 1
Course Overview Motivation
Standardization issues
UMTSarchitecture basics
UE,UTRA,UTRAN,PSDomain,CSDomain Basicfunctionalities:
Accessing the network
Transferringdata
Detaching from the network
Informationstorage
Mobility
QoS
Security
Charging
IMS
Example signaling flows
UMTSEvolution:from R99toRel6
Beyond UMTS
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 2
UMTS architecture basics Principles ofnetwork architectures
Forcomparison:GSMarchitecture
Forcomparison:GPRSarchitecture
Conceptual UMTSarchitecture
UE UTRAN
PSDomain
CSDomain IMS
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 3
Principles of network architectures
Anetwork architecture is defined by
functional groups
defined by aset offunctions
reference points
conceptual points separating functional groups
The concept offunctional groups may be applied ina
hierarchical manner
The functions ofafunctional group may be performed by
one or more physical piece ofequipment
Areference pointmay represent aphysical interface
between pieces ofequipment
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 4
Principles of network architectures
High level view of a mobile network architectureMobile Station (MS) or
User Equipment (UE)
U
I
G
Functional Group
Reference PointU
External Networks (Internet, PSTN,...)
Radio Access Network (RAN)
Core Network (CN)
Each FunctionalGroupis
responsible for well-defined
functionality E.g.radio resource management
Modularstructure allows building
blockapproach
Can exchange e.g.RANwithout
influencing the rest
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 5
UMTS architecture basics Principles ofnetwork architectures
Forcomparison:GSMarchitecture
Forcomparison:GPRSarchitecture
Conceptual UMTSarchitecture
UE UTRAN
PSDomain
CSDomain IMS
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 6
For comparison: GSM GSMis acircuit switchednetwork
asopposed topacketswitched networks based e.g.onIP
for allservices (e.g.voice,fax,wap)anend-to-end
connection is established
allservices are reserved the identical bandwidth
wasteful particularly onradio interface
allservices are charged onaper-timeunit basis
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 7
Simplified GSM architecture
External Networks
Base Station Subsystem (RAN)
Routing (MSC)
Mobility management (MSC)
Collection of charging information (MSC)
Subscriber management (MSC)
Interworking with external networks (GMSC)
Data storage, e.g. suscriber profiles, current MSC
(HLR, AuC, EIR / VLR)
User interface and Radio interface
Service control
User Identity Module (SIM, unique identification of user)
Core Network (CN)
Mobile Station (MS)
receive / send data from / to MS via radio link (BTS)
control Radio specific signaling (BSC)
Radio resource management (BSC)
Transcoding and rate adaptation (TRAU)Transform e.g. voice coding from one digital format
into another one, e.g. ISDN to GSM
Um
A
BSC
BTS
BTS
BTS
BTS
MSC
GMSC
VLR HLR
AuC
EIR
TRAU
Packet Data
NetworksISDN GSMPSTN
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 8
UMTS architecture basics Principles ofnetwork architectures
Forcomparison:GSMarchitecture
Forcomparison:GPRSarchitecture
Conceptual UMTSarchitecture
UE UTRAN
PSDomain
CSDomain IMS
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 9
GSMis acircuit switchednetwork
since anoverall increase ofdata trafficis expected,GSMwasevolvedtobecome more flexible->GPRS (GeneralPacketRadioService)
GPRSis called 2.5Generation
GPRSadds technologyfor supporting data traffic:
apacketswitched domain tothe core network
ashared channel onthe radio link
shared channel means several users share the same radio channel
asopposed toadedicated channel asinGSMmore efficient usage ofresources,because ofstatistical multiplexing
Allapplications share the same resource
Efficient for applications with variablerates
Can take away resources from each other
higher transmission rates (max 171,2kb/s) GSMoriginally hasupto14,4kb/s
With EDGE384kb/spossible
allows adirect connection toe.g.the Internet
charging perdata volume possible
inGSMalways charging pertimeunit
For comparison: GPRS
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 11
UMTS architecture basics Principles ofnetwork architectures
Forcomparison:GSMarchitecture
Forcomparison:GPRSarchitecture
Conceptual UMTSarchitecture
UE UTRAN
PSDomain
CSDomain IMS
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 12
Add anew radio access network,the UTRANUTRAN- UMTSTerrestrial RadioAccessNetwork
UTRANandGSMradio access network can coexist and
connect tothe same Core Network
The CSDomain may alsobe based onpacketbased transport slow evolution towards all-IP-- may be some day abandon the circuit
switched domain alltogether
Introduction ofthe IMSIMS- IPMultimediaSubsystem
support ofIP-based multimedia services
multimedia services are e.g.
Video,voice,possibly simultaneously with data etc.
e.g.IMSvitalfor locating IP-address ofaddressees
the PSdomain justprovides QoS,
it does notprovide multimedia services (app.layer)
the PSdomain serves asaccess system tothe IMS
the IMSinprinciple is access-system independent(alsoETSIis interested)
the PSdomain hides mobility from the IMS
UMTS - Main changes from GPRS
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 13
UMTS basic network architecture
External Networks (Internet, PSTN,...)
UMTS RadioAccess
Network
(UTRAN)
Core Network (CN)
packet
switched
domain
PS domain
circuit
switched
domain
CS Domain
User Equipment (UE)
IP Multimedia
Subsystem (IMS)Gi
Iu-ps
Iu-cs
Gi
Base StationSubsystem
from GSM
Gb
A
Radio Access Network (RAN)
Radio link between UTRAN and UE is
called UTRA
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WS 04/05, TKN TU Berlin, Cornelia Kappler Course UMTS Networks, III. UMTS Architecture 14
Summary The mobilenetworks we are looking atconsist of
UE/MS,RANandCN
they provide access toexternal networks
GSMis circuit switched
GPRSadds support for packetswitching
UMTSevolves from GPRSby adding anew RAN
adding the IMS
AUMTSNetworkconsists of UE
UTRAN
Core Network(CSDomain,PSDomainandIMS)
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