UMTS Networks 1Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS System Architecture and Protocol Architecture
Overview on overall system architecture UMTS network architecture and elements Mobile station High-level functions UMTS domains and strata UMTS/GPRS protocol architecture
References: Kaaranen, Ahtiainen, Laitinen, Naghian, Niemi: UMTS Networks Architecture, Mobility and
Services. 2nd edition, Wiley 2005 Ch 5.1: Core Network Architecture Release 3 Ch 5.4&5.5: Core Network Architecture Release 4 and 5 Ch 6: UMTS Terminal
3GPP TS 23.002: UMTS network architecture (CN and AN entities) and procedures 3GPP TS 23.101: General UMTS architecture 3GPP TS 23.060: GPRS, Service Description 3GPP TS 21.101/21.102/21.103: List of standards for Release 3, 4 and 5, respectively 3GPP TR 21.905: UMTS vocabulary and abbreviations
UMTS Networks 2Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS/GSM Network Architecture
GPRS Core(PacketSwitched)
SGSN
GGSN
Internet
GSMRAN
Base stationBase stationcontroller
Base station
Base station
UTRAN
Radio networkcontroller
node Bnode B
node B
MSC
ISDN
GSM Core (Circuit switched)
HLRAuCEIR
GMSC
UMTS Networks 3Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS System Architecture
UMTS Subscriber Identity Module (USIM): subscriber-specific data support of authorized access to network
Mobile Station (MS): radio interface service control and user interface
Radio Access Network (RAN): radio-specific functions
Core Network (CN):radio-independent functions transport mobility management subscriber data service control
datanetworks
ISDNnetwork
mobilenetwork
USIM
UMTS Networks 4Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
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A IuPS
Iur
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MSC SGSN
Gs
GGSN GMSC
GnHLR
Gr
GcC
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AuC H
EIR
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GiPSTN
IuCSGb
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VLR G
BTS BTS
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Packet switched CN
GSM RAN
UTRAN
UMTS Networks 5Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Mobile-services Switching Centre (MSC)
An exchange performing all the switching and signalling functions (CS only) for mobile stationsMSC controls mobile-originated and mobile-terminated CS calls
Functions call management mobility management (handling attach and authentication) subscriber administration maintenance of charging data (for radio network usage) CS data services (FAX, modem) supplementary call services (call forwarding, etc.) SS7-based signaling
Main difference to an exchange in a fixed network: deal with mobility (e.g. location registration, handover)
Gateway MSC (GMSC) Provides interconnection between the UMTS core network and external
PSTN/ISDN networks
Source: 3GPP 23.002-3.5.0
UMTS Networks 6Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
GPRS Support Node (GSN) GSNs constitute the interface between the radio access network and the fixed networks for packet switched services (similar to MSC for CS calls)
Serving GSN (SGSN)
session management mobility management subscriber database management (interface with HLR) maintenance of charging data (for radio network usage) IP-based transport of user data between SGSN and the UTRAN IP- or SS7-based signaling transport
Gateway GSN (GGSN)
gateway for UMTS packet service to external data networks (e.g. the Internet)
IP interface towards SGSN performs user data screening and security maintenance of charging data (for external data network usage)
Source: 3GPP 23.002-3.5.0
UMTS Networks 7Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Home Location Register (HLR)Home (primary) data base in charge of the management of mobile subscribersBasic information: International Mobile Subscriber Identity (IMSI) CS subscription information
one or more Mobile Subscriber International ISDN number(s) (MSISDN)
PS subscription information zero or more Packet Data Protocol (PDP) address(es) permission for GGSN to dynamically allocate PDP addresses for a
subscriber location information enabling the charging and routing of calls towards
the MSC or SGSN where the MS is registered (e.g. VLR Number)
Other information: teleservices and bearer services subscription information service restrictions (e.g. roaming limitation) parameters attached to supplementary services
Source: 3GPP 23.002-3.5.0
UMTS Networks 8Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Visitor Location Register (VLR)(Secondary) data base supporting the management of mobilesubscribers currently located within its VLR area
Motivation: minimize load for HLR (i.e. of the primary data base)
Tasks: control MSs roaming in an MSC assigned to it exchange information with HLR to allow the proper handling of calls
Information maintained by VLR (for call handling):
International Mobile Subscriber Identity (IMSI) Mobile Station International ISDN number (MSISDN) Mobile Station Roaming Number (MSRN) Temporary Mobile Station Identity (TMSI), if applicable location area where the mobile station has been registered the last known location and the initial location of the MS supplementary service parameters attached to the mobile subscriber
(received from the HLR)
Source: 3GPP 23.002-3.5.0
UMTS Networks 9Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Authentication Centre (AuC)
Stores data for each mobile subscriber to authenticate the International Mobile Subscriber Identity (IMSI) to support ciphering of the communication over the radio path
The AuC transmits the data needed for authentication and ciphering via the HLR to the VLR, MSC and SGSN which need to authenticate a mobile station
AuC is associated with an HLR, and stores an identity key for each mobile subscriber
The AuC communicates solely with its associated HLR (H-interface)
Source: 3GPP 23.002-3.5.0
UMTS Networks 10Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Equipment Identity Register (EIR)
Logical entity storing the International Mobile Equipment Identities (IMEIs)
Equipment is classified as
white listed: serie number of equipment
grey listed: equipment tracked by network
black listed: barred equipment
unknown to EIR
Source: 3GPP 23.002-3.5.0
UMTS Networks 11Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Other CN entitiesSMS Gateway MSC (SMS-GMSC) gateway between Short Message Service Center and PLMN deliver SMSs from service center to MS
SMS Interworking MSC (SMS-IWMSC) gateway between PLMN and Short Message Service Center deliver SMSs from MS to service center
Interworking Function (IWF) associated with MSC supports interworking of PLMN with fixed networks, e.g. ISDN, PSTN,
PDN (protocol conversion)Border Gateway (BG) PS gateway to other PLMNs firewall functionality
Charging Gateway Functionality (CGF) collects charging records from SGSNs and GGSNs
Source: 3GPP 23.002-3.5.0
o
UMTS Networks 12Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Radio Network System (RNS)
Provide access to the UMTS terrestrial radio interface
RNS
RNC
RNS
RNC
Core Network
Node B Node B Node B Node B
Iu Iu
Iur
Iub IubIub Iub
UTRAN
Radio Network Controller (RNC) (Radio) mobility management Management of radio resources
Base Station (Node B) Radio coverage of cells Physical layer processing
UMTS Networks 13Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Mobile Station (MS)
ITU-T Recommendyer UE
Mobile Equipment (ME) Mobile Termination (MT)
RTAF
Cu
Access Network
UuTerminal Equipment (TE)
USIM
Mobile Equipment (ME)radio transmission and application
Terminal Adaptation Functions (TAF)(service dependent) mapping of terminal requests on
network capabilities flow control/rate adaptations
Terminal Equipment (TE)support for end-to-end applicationfunctions necessary for the operation of the access protocols by the user, e.g. a laptop
UMTS Subscriber Identity Module (USIM)user identitycontains data and procedures to unambiguously and securelyidentify itself
Mobile Termination (MT)functions for radio transmissionand management of the radio interface, e.g. the handset
Mobile station (MS)/User Equipment (UE)physical equipment used by a PLMN subscriber
o
UMTS Networks 14Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS High-level Functions (PS Domain)Network Access Control
Provide means by which a user is connected to a telecommunication network
RegistrationAssociation of Mobile ID with the user's packet data protocol(s) and address(es) within the PLMN, and with the user's access point(s) to the external PDP network
Authentication and AuthorisationIdentification and authentication of the service requester, and the validation of the service request type
Admission ControlCheck available network resources required to provide the quality of service (QoS)
Message ScreeningA screening function with filtering out unauthorised or unsolicited messages(firewall)
Charging Data CollectionCollection of data necessary to support subscription and/or traffic fees
Operator Determined BarringLimitation of the service provider's financial risk with respect to new subscribers or to those who have not promptly paid their bills by restricting a particular packet-switched service
UMTS Networks 15Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS High-level Functions (PS Domain)Packet Routing and Transfer
Determining and using the route for transmission of a message within and between the PLMN(s)
ForwardingForwarding of data received from one node to the next node in the route
RoutingSelection of the transmission path for the "next hop" in the routeusing the destination address of the message
Address Translation and MappingConversion of one address to another address of the same ordifferent type, i.e. to convert an external network protocol address into an internal network address
Encapsulation/DecapsulationAddition/removal of address and control information to a data unit for routing packets within and between the PLMN(s)and between the SGSN and the MS
TunnelingTransfer of encapsulated data units within and between the PLMN(s) from the point of encapsulation to the point of decapsulationA tunnel is a two-way point-to-point path
CompressionOptimisation of radio path capacity
CipheringPreservation of the confidentiality of user data and signalling across the radio channels
Mobility Management Keep track of location of MS...
UMTS Networks 16Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS Functional Entities: DomainsDomain: grouping of physical entities of the system
User Equipment (UE) Domain
Access Network (AN) Domain
Core Network (CN) Domain
Infrastructure Domain
Cu
Mobile Equipment Domain
USIM Domain
Home Network Domain
Transit Network Domain
Uu Iu
[Zu]
[Yu]
Serving Network (SN) Domain
Source: 3GPP 23.101-4.0.0
Air InterfaceRadio Access Network (RAN)
UMTS Networks 17Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Functions of the UMTS DomainsInfrastructure domain Access network (AN) domain: functions specific to access technique Core network (CN) domain: functions independent of access technique
Access network domain physical entities managing the resources of the access network provides the user with a mechanism to access the core network domain
Serving network (SN) domain part of the CN domain to which the AN domain that provides the users
access is currently connected responsible for routing calls and transport user data/information from source
to destination provides CN functions that are local to the users access point (i.e. SN
changes when the user moves) Home network (HN) domain provides CN functions that are conducted at a permanent location regardless
of the location of the users access point (i.e. does not change due to user mobility)
contains user-specific data and is responsible for management of subscription information
handle home-specific services, not offered by the serving network domainUser Services Identity Module domain (USIM) related to the home network domain by subscription
UMTS Networks 18Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Functional Communication between UMTS domains
Source: 3GPP 23.101-4.0.0
USIM
MT - AN
MT/MEAccess Network Domain
Serving Network Domain
Home Network Domain
AN - SN
Access Stratum
MT - SN
Serving Stratum
USIM - HN
SN - HN
Home Stratum
MT - SN USIM - MT
Transport Stratum
USIM - MT
Transport of user data and network control signalling error correction and recovery encrypt data over the radio interface
and in the infrastructure part adaptation of data to use the supported
physical format transcoding of data to make efficient
use of, e.g. the radio interface
Parts of infrastructure, user equipment and protocols specific to the access technique provides services related to the transmission
of data over the radio interface and the management of the radio interface
Protocols and functions to route and transmit data/information (user or network generated) from source to destination
Protocols and functions related to the handling and storage of subscription data and possibly home network specific services
functions related to subscription data management, customer care, including billing and charging, mobility management and authentication
functions to allow domains other than the home network domain to act on behalf of the home network
Strata concept: grouping of functions grouping of
respective protocols
o
UMTS Networks 19Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Functional Communication between UMTS domains
Source: 3GPP 23.101-4.0.0
End-to-end protocols and functions which make use of services provided by the home, serving and transport strata and infrastructure to support services and/or value added services.The functions and protocols within the application stratum may adhere to GSM/UMTS standards such as MExE or may be outside the scope of the UMTS standards.
TE
MT - AN
MT Access Network Domain
Serving Network Domain
Transit Network Domain
AN - SN
Access Stratum
TE - MT MT - SN
Serving Stratum
Application Stratum
Application
Transport Stratum
Remote Party
Mobile Equipment
Domain
o
ow1
Folie 19
ow1 Hier ist das Serving Stratum seltsam!Oliver Waldhorst; 17.10.2011
UMTS Networks 20Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS Protocol Architecture
References: Kaaranen, Ahtiainen, Laitinen, Naghian, Niemi: UMTS Networks Architecture, Mobility
and Services. Wiley 2001, Ch. 5.1 Walke, et al: UMTS ein Kurs, Ch. 5 (air interface only) 3G TS 23.060: GPRS, Service Description
We will focus on the packet switched mode here
UMTS Networks 21Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
User Plane Bearer Services Overview
TE MT UTRAN CN IuEDGENODE
CNGateway
TE
UMTS
End-to-End Service
TE/MT LocalBearer Service
UMTS Bearer Service External BearerService
UMTS Bearer Service
Radio Access Bearer Service CN BearerService
BackboneBearer Service
Iu BearerService
Radio BearerService
UTRAFDD/TDD
Service
PhysicalBearer Service
UMTS Networks 22Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
Bearer Services Analogy with Public Transportation
TE MT UTRAN CN IuEDGENODE
CNGateway
TE
UMTS
End-to-End Service
TE/MT LocalBearer Service
UMTS Bearer Service External BearerService
UMTS Bearer Service
Radio Access Bearer Service CN BearerService
BackboneBearer Service
Iu BearerService
Radio BearerService
UTRAFDD/TDD
Service
PhysicalBearer ServiceTaxi:
Flat bus stop
Walk to taxi
Bus: Bus stop railway station
Train: Station station
Combo ticket: bus and taxi
Taxi, bus and train combo:single ticket, single reservation, same service everywhere
Taxi with driver Bus with driver
For each bearer: specific attributes (delay,
bandwidth, guarantees, etc. specific reservation
mechanism
UMTS Networks 23Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
MS-RNS-SGSN-GGSN User Plane
L1
RLC
PDCP
MAC
E.g., IP,PPP
Application
L1
RLC
PDCP
MAC
ATM
UDP/IP
GTP-U
AAL5
Relay
L1
UDP/IP
L2
GTP-U
E.g., IP,PPP
3G-SGSNUTRANMSIu-PSUu Gn Gi
3G-GGSN
ATM
UDP/IP
GTP-U
AAL5
L1
UDP/IP
GTP-U
L2
Relay
Source: 3GPP 23.060-4.1.0
UMTS Networks 24Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
MS-RNS-SGSN-GGSN User Plane
L1
RLC
PDCP
MAC
E.g., IP,PPP
Application
L1
RLC
PDCP
MAC
ATM
UDP/IP
GTP-U
AAL5
Relay
L1
UDP/IP
L2
GTP-U
E.g., IP,PPP
3G-SGSNUTRANMSIu-PSUu Gn Gi
3G-GGSN
ATM
UDP/IP
GTP-U
AAL5
L1
UDP/IP
GTP-U
L2
Relay
Source: 3GPP 23.060-4.1.0
GTP-U (GPRS Tunneling Protocol for User plane): tunneling of user data between UTRAN and the 3G-SGSN tunneling between the GSNs in the backbone network encapsulation of all PDP PDUs
UMTS Networks 25Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
MS-RNS-SGSN-GGSN User Plane
L1
RLC
PDCP
MAC
E.g., IP,PPP
Application
L1
RLC
PDCP
MAC
ATM
UDP/IP
GTP-U
AAL5
Relay
L1
UDP/IP
L2
GTP-U
E.g., IP,PPP
3G-SGSNUTRANMSIu-PSUu Gn Gi
3G-GGSN
ATM
UDP/IP
GTP-U
AAL5
L1
UDP/IP
GTP-U
L2
Relay
Source: 3GPP 23.060-4.1.0
PDCP (Packet Data Convergence Protocol):
provides protocol transparency (wrt the underlying radio-interface protocols) for higher-layer protocols
support for e.g., IPv4, PPP and IPv6 (easy introduction of new higher-layer protocols)
compression of control information(header compression)
no user data compression in Iu mode(because the data compression efficiency depends on the type of user data)
UMTS Networks 26Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
MS-RNS-SGSN-GGSN User Plane
L1
RLC
PDCP
MAC
E.g., IP,PPP
Application
L1
RLC
PDCP
MAC
ATM
UDP/IP
GTP-U
AAL5
Relay
L1
UDP/IP
L2
GTP-U
E.g., IP,PPP
3G-SGSNUTRANMSIu-PSUu Gn Gi
3G-GGSN
ATM
UDP/IP
GTP-U
AAL5
L1
UDP/IP
GTP-U
L2
Relay
Source: 3GPP 23.060-4.1.0
RLC (Radio Link Control): RLC protocol provides logical link control over the radio interfaceThere may be several simultaneous RLC links per MS; each link is identified by a Bearer Id
MAC (Medium Access Control): MAC protocol controls the access signaling (request and grant) procedures for the radio channel
UMTS Networks 27Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
MS-RNS-SGSN-GGSN Control Plane
UDP
L2
L1
IP
L2
L1
IP
UDP
Gn or Gp
GSN GSN
GTP-C GTP-C
RLC
RRC
L1
GMM /SM / SMS
RRC
MAC
ATM
RANAP
AAL5
Relay
ATM
AAL5
3G SGSNRNSMSIu-PsUu
RLC SCCP
SignallingBearer
MAC
L1
SignallingBearer
RANAP
SCCP
GMM /SM / SMS
o
UMTS Networks 28Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
MS-RNS-SGSN Control PlaneGMM (GPRS Mobility Management):
GMM supports mobility management functionality such as attach, detach, security, and routing area update
SM (Session Management): SM supports PDP context activation and deactivation
SMS supports short message service
GTP-C (GPRS Tunneling Protocol for Control plane): establish, manage and release GTP tunnels
RANAP (Radio Access Network Application Protocol): transport of higher-layer signalling handling of signalling between the 3G-SGSN and UTRAN management of the GTP connections on the Iu interface
RRC (Radio Resource Control): Information Broadcast (AS and NAS) RRC connection management (setup, release, reconfiguration) Radio Bearers management (setup, release, reconfiguration) Management of radio resources for the RRC connection RRC connection mobility functions Paging/notification
Source: 3GPP 23.060-4.1.0
UMTS Networks 29Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS Protocol Architecture: The Complete Picture (Packet Switched)
Q2150.1
SGSNRNCNode B
Control Plane User Plane Transport Plane Common
MM
SM
MAC
Phy-up
PHY
codec
RRC
RLC
PMM
SM
MAC
Phy-up
PHY
RRC
IP
PDCP
RLC
SSCOP
NBAP
AAL5
SSCOP
ALCAP
AAL5
SSCF SSCF FP
AAL2 AAL2 AAL5 AAL5
SSCF
RLC
MAC
Phy-up SCCP
FP
RRC
ATM
E1
NBAP
AAL5 AAL2
SSCOP
MTP3-b
SSCF-N
SCCP
RANAP
RRC
ATM
STM-1
GTP-U
UDP
PDCP
ALCAP
STC.2
SSCF-UNI
SSCOP
IP
RLC
MAC
Phy-up
FP
AAL5
ATM
E1
FP
AAL2
SSCOP
ALCAP
AAL5
SSCOP
NBAP
AAL5
SSCF SSCF
PHY
ATM
E1/ STM-1
AAL2 AAL5
NBAP
PHY
ALCAP
SSCOP
STC.2
SSCF-UNIFP
SSCOP
MTP3B
AAL5
SSCF
Q2150.1
Q2150.1
Iu UP
ATM
E1
AAL2
SSCOP
MTP3B
AAL5
SSCF
SCCP
SM
MM
RANAP
SSCOP
MTP3-b
SSCF-N
SCCP
PMM
SM
ATM
STM-1
AAL5
IP
GTP-U GTP-C
UDP
L1
L2
SSCOP
MTP3B
AAL5
SSCF
Q2150.1
Q2150.1
IP
GTP-C
L1
GTP-U
UDP
L2
IP
GGSNUu Iub Iups Gn
o
UMTS Networks 30Andreas Mitschele-Thiel, Jens Mckenheim Oct-12
UMTS Protocol Architecture: The Complete Picture (Circuit Switched)
3G-MSCRNCNode B
AA
MM
SM
MAC
Phy-up
PHY
codec
RRC
RLC
MM
CM
MAC
Phy-up
PHY
RRC
MTP
AAL5
SSCF
Iu UPQ2150.1
ATM
E1
AAL2
SSCOP
MTP3B
AAL5
SSCF
SCCP
SM
MM
RANAP
Iu UPSTC.1
ALCAP
STM-1
AAL2
SSCOP
MTP3B
AAL5
SSCF-NNI
SCCP
MM
CM
ATM
E1
FP
AAL2
STC.2
SSCOP
NBAP
AAL5
SSCF-UNI
PHY
ALCAP
Uu Iub Iucs
SSCOP
NBAP
AAL5
SSCOP
ALCAP
AAL5
SSCF SSCF FP
AAL2 AAL2
RLC
MAC
Phy-up
RRC
ATM
E1
NBAP
AAL5
SSCOP
MTP3-b
SSCF-NNI
SCCP
RANAP
ATM
STM-1
ALCAP
STC.2
SSCF-UNI
SSCOP
Iu UP
MAC
Phy-up
FP
AAL5
codec RRC
RLC
AAL2
ALCAP
STC.1
ATM
codec
RLC
Control Plane User Plane Transport Plane Common
o
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