umts system architecture and protocol architecture€¦ · · 2017-11-05umts system architecture...

UMTS Networks 1Andreas Mitschele-Thiel, Jens Mückenheim 19-Oct-10

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

• Walke, Althoff, Seidenberg: UMTS – Ein Kurs. J. Schlembach Fachverlag, 2001• 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/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 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


Public Land Mobile Network (PLMN)

Definition:

– a network established and operated by an administration to provide land-based mobile telecommunications services to the public

– a PLMN may be regarded as an extension of a network (e.g. an ISDN)

– a PLMN consists of a collection of MSC areas within a common numbering plan (e.g. same National Destination Code) and a common routing plan

– PLMNs are independent telecommunications entities

Source: 3GPP 23.002-5.5.0


UM

TS N

etw

ork

Arc

hite

ctur

eB

asic

Con

figur

atio

n, R

elea

se 3

BSS

BSC

RNS

RNC

CN

Node B Node B

A IuPS

Iur

Iub

Uu

MSC SGSN

Gs

GGSN GMSC

GnHLR

Gr

GcC

D

E

AuC H

EIR

F Gf

GiPSTN

IuCSGb

VLR B

Gp

VLR G

BTS BTS

Um

RNC

Abis

MSC

B

PSTNPSTN

cellSour

ce:

3GPP

23.

002-

3.4.

0

Circ

uit

switc

hed

CN Packet switched CN

GSM RAN

UTRAN


Logical Architecture

Gf

Uu

Um

D

Gi

Gn

IuGc

CE

Gp

Gs

Signalling and Data Transfer Interface Signalling Interface

MSC/VLR

TE MT UTRAN TEPDN

GrIu

HLR

Other PLMN

SGSN

GGSN

Gd

SM-SC SMS-GMSC

SMS-IWMSC

GGSN

EIR SGSN

GnCGF

GaGa

BillingSystem

GbTE MT BSS

R

AR

CAMEL GSM-SCF

Ge

Source: 3GPP 23.060-3.8.0


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


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


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


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


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


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


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

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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


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 labtop

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

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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)

• Packet Terminal AdaptationAdaptation of data packets suitable for transmission across the packet domain network

• 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


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)

• RelayForwarding 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 MSRadio Resource Management• Management of radio resources


Mapping of Functions to Logical Architecture (PS Domain)

Function 2G-MS 3G-MS BSS UTRAN 2G-SGSN

3G-SGSN GGSN HLR

Network Access Control:Registration XAuthentication and Authorisation X X X X XAdmission Control X X X X X XMessage Screening XPacket Terminal Adaptation X XCharging Data Collection X X X

Packet Routing & Transfer:Relay X X X X X X XRouting X X X X X X XAddress Translation and Mapping X X X X X X

Encapsulation X X X X X XTunneling X X X XCompression X X X XCiphering X X X X X

Mobility Management: X X X X X X

Logical Link Management:Logical Link Establishment X XLogical Link Maintenance X XLogical Link Release X X

Radio Resource Management: X X X X X

Source: 3GPP 23.060-3.8.0

GSMonly


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)


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 user’s 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 user’s 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 user’s 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 domain

User Services Identity Module domain (USIM) – related to the home network domain by subscription


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

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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


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


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


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 Service

Taxi: Wohnung –Bushaltestelle

Zu Fuß zum Taxi

Bus: Bushaltestelle - Bahnhof

Bahn: Bahnhof - Bahnhof

Taxi und Bus im Verbund (Taxiruf im Bus)

Taxi, Bus und Bahn im Verbund: single ticket, single reservation, same service everywhere

Taxi mit Fahrer Bus mit Fahrer

For each bearer: • specific attributes (delay,

bandwidth, guarantees, etc.• specific reservation

mechanism


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


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


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



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-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



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-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)



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-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 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 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

umts system architecture and protocol architecture€¦ · · 2017-11-05umts system architecture...

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