migration toward 4g and all-ip concept. wfi confidential & proprietary page 2 global...

Migration Toward 4G and All-IP Concept

WFI Confidential & Proprietary

Global Standardization ActivitiesGlobal Standardization Activities

USA EuropeJapan Japan

GPRS/EDGET1 ETSI

SMG2

TDMA/UWCCTR45.3

TIA

CDMA/IS95TR45.4

TIA

WCDMA3GPP

T1CWTS

ETSI TTC

ARIBTTA

cdma20003GPP2

DDI-IDO TIA

ITU

TIATTACWTS

ETSIARIBTTC

IMT2000

ITUHARMONIZATION


IMT2000 Main ParticipantsIMT2000 Main Participants

Industry Standard Groups -ARIB - Association of Radio Industries and Business (Japan)ETSI - European Telecommunications Standards Institute (Europe)ITU - International Telecommunications UnionTIA - Telecommunications Industry Association (USA)TTA - Telephone and Telegraph Association (S.Korea)

KoreaKorea

ETSIWCDMA

&TD-CDMA

EuropeEurope

ARIB

ITU-R

TIATR45.5 &

TR45.3

TTA (I & II)

JapanJapanU.S.U.S.

CDMA2000 &

UWC-136

EDGE


IMT-2000 Radio Transmission Technology CandidatesIMT-2000 Radio Transmission Technology Candidates•Universal Wireless Communications (UWC-136) - USA TIA

TR45.3•Time-Division Synchronous CDMA (TD-SCDMA) - China

Academy of Telecommunication Technology (CATT)•Wireless Multimedia & Messaging Services Wideband CDMA

(WIMS:CDMA) USA TIA TR46.1•UMTS Terrestrial Radio Access: Wideband CDMA (UTRA: W-

CDMA) -ETSI SMG2•Wideband CDMA (W-CDMA) - Japan ARIB•Wideband CDMA: IS-95 (cdma2000) - USA TIA TR45.5•Multiband synchronous DS-CDMA (CDMA I) - S. Korea TTA•Digital Enhanced Codeless Telecommunications (DECT) - ETSI


Current Standardization ActivitiesCurrent Standardization Activities

3GPP (Third Generation Project Partnership)

Members:ETSI (Europe)ARIB/TTC (Japan)T1 (USA)TTA (S.Korea)CWTS (China -Associate)

System Specification: Access network: WCDAM (FDD)

TDCDMA (TDD)Core network Evolved GSM & All-IP

3GPP (Third Generation Project Partnership)

Members:ETSI (Europe)ARIB/TTC (Japan)T1 (USA)TTA (S.Korea)CWTS (China -Associate)

System Specification: Access network: WCDAM (FDD)

TDCDMA (TDD)Core network Evolved GSM & All-IP


Current Standardization ActivitiesCurrent Standardization Activities

3GPP2 (Third Generation Project Partnership2)

Members:TIA (USA)ARIB/TTC (Japan)TTA (S.Korea)CWTS (China)

System Specification: Access network: cdma2000 (1x & 3x)Core network Evolved IS-41& All-IP

3GPP2 (Third Generation Project Partnership2)

Members:TIA (USA)ARIB/TTC (Japan)TTA (S.Korea)CWTS (China)

System Specification: Access network: cdma2000 (1x & 3x)Core network Evolved IS-41& All-IP


Path to 3GPath to 3G

Analog Digital

1989-19991984-1988 2000-2002 2003-2005

GPRS

IS-95

iDEN

IS-136

EDGE

GSM

W-CDMA

CDMA 2000HDR1xRTT

Today

Source: CSFB

14.4 kbps 144 kbps 384 kbps 2 Mbps


GSM Network ArchitectureGSM Network Architecture

BTS

MS

Um

BTS

BTSBSC

Base Station Subsystem (BSS)

A-bisA

BTS: Base Transceiver StationBSC: Base Station ControllerHLR: Home Location RegisterVLR: Visited Location RegisterOMC: Operation & Maintenance CentreEIR: Equipment Identity RegisterAUC: Authentication Centre

MobileServicesSwitchingCentre(MSC)

HLREIR VLR OMC

AUC

F

H G

BC

other MSCs

E

PSTN ISDN CSPDN PSPDN

other VLRs

other BSSs

D


GPRS ConceptGPRS Concept

•The General Packet Radio Service (GPRS) is a new value added service introduced in order to provide more

efficient access to packet data networks from cellular networks. utilizes packet switching technology where information is

transmitted in short bursts of data over an IP-based network. It provides a quick session set up and fast data transmission

speeds. Supports immediacy (no dial-up connection is necessary) It can use multiple time slots for data transfer as opposed to a

normal single time slot. Enables the Internet applications not available previously on GSM

networks It supplements today's Circuit Switched Data and Short Message

Service in GSM networks. theoretically supports maximum speeds of up to 171.2 kbps

•GPRS shares GSM frequency bands with voice and circuit switched data traffic, and makes use of many properties of the physical layer of the original GSM system to simplify the introduction of new services


GPRS Services and ApplicationsGPRS Services and Applications

•Supports two kinds of end-to-end packet switched data transfer: Point-to-Point (PTP) services:

– PTP connectionless network services for IP

– PTP connection oriented network services for X.25

Point-to-Multipoint (PTM) services:– PTM-M: Multicast services broadcasts packets in certain geographical areas

– PTM-G: Group call services address packets to a group of users in a particular geographical area

•Always on and pay per byte concept•New ApplicationsBusiness Subscribers Consumers Subscribers

•Email/schedule•E-commerce•FTP i.e. file transfer•Web browsing•Emails

•Banking•E-commerce•Information Services•Internet•Emails•WAP


Quality of ServiceQuality of Service

•QoS classes are set per session, they include: Service precedence: priority of a service in relation to other

services Reliability: required transmission characteristics (3 classes are

defined) Throughput: maximum peak bit-rate and the mean bit rate Delay: maximum value of mean delay

Billing is based on data volume, type of service and QoS profile

128 byte packet 1024 byte packetClassMean Delay 95% Delay Mean Delay 95% Delay

1 <0.5 s <1.5 s <2 s <7 s2 <5 s <25 s <15 s <75 s3 <50 s <250 s <75 s <375 s4 Best Effort Best Effort Best Effort Best Effort


GPRS Mobile ClassesGPRS Mobile Classes

•There are three classes of mobile stations (MSs) Class A mobile station supports simultaneous operation of GPRS

and conventional GPRS services Class B mobile station is able to register with network for both GPRS

and conventional GSM services simultaneously. In contrast to an MS of class A, it can only use one of the two services at a given time

Class C mobile station ca attach for either GPRS or conventional GSM services. Simultaneous registration or usage is not possible. An exception are SMS messages which can be received and sent at any time

•Mobile stations also have different classes based on their multi-slot capabilities on the TX and RX sides e.g. 3 Time slot Receive and 1 Transmit


GPRS Main AttributesGPRS Main Attributes

•Consists of packet wireless access network and IP-based backbone

•Shares mobility databases with circuit voice services and adds new packet switching nodes (SGSN & GGSN)

•Will support GPRS, EDGE & WCDMA air interfaces•Radio resources shared dynamically between speech and data

services•GPRS is designed to minimize hardware modifications on

existing network elements : Addition of a new hardware component in the BSS, the PCU, which

integrates most of the BSS new functions and manages RLC/MAC layers

BSC and BTS are impacted as few as possible Entirely new core network with many functions, for the packet-

switched services The HLR is enhanced with GPRS subscriber data and routing

information


GPRS Network Components and InterfacesGPRS Network Components and Interfaces

PCU

Gb

Gs

Gi

Gc

SGSN

GGSN

GrGn

Gp

Gp

PSTNCN (Core Network)

PDN (Internet)CN (Core Network)

CN (Core Network)RAN (Radio Access Network)

CS

(C

i rcu i

t S

witc

h )P

S (

Pa

cket

Sw

itch)

Um

EIR

A

BTS

BSC

BTS

MSC/VLR

GMSC

HLR/AC

Abis

C

D

F

40

50

Q100

Gf

Mobile data solution built upon the existing GSM Infrastructure and Mobility Management

Gateway GPRS Support Node (GGSN) is responsible for routing data packets entering and leaving the radio network

Serving GPRS Support Node is responsible for packet delivery to mobiles in different areas and interrogates the GSM databases for mobile profiles


GPRS Protocol StackGPRS Protocol Stack

Relay

NetworkService

GTP

Application

IP / X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

Relay

L2

L1

IP

L2

L1

IP

GTP

IP / X.25

Um Gb Gn GiMS BSS SGSN GGSN

NetworkService

UDP /TCP

UDP /TCP

Relay


Required Changes in the Current GSM Networks Required Changes in the Current GSM Networks • GPRS is implemented on the top of GSM infrastructure by

adding two main network elements: Gateway GPRS support node (GGSN) Serving GPRS Support Node (SGSN)

• In addition to the new GPRS elements, existing GSM and TDMA (IS136) network elements should also be enhanced in order to support GPRS. Following two must be enhanced: Base Station System (BSS): must be enhanced (software upgrade)

to recognize and send users data to SGSN that is serving the area. PCU interface is required to cater data traffic.

Home Location Register (HLR): changes (software upgrade) should be made in HLR to register GPRS user’s profile and respond to queries originating from SGSN’s regarding these profiles.

MSC/VLR: Existing hardware could be used but Software upgrade is required.

• Mobile stations also need to be upgraded both in hardware and software to allow for multislot operation and variable coding.


GGSN FunctionsGGSN Functions

• Acts as a logical interface between the GPRS network and the external public data networks such as IP and X.25

• It converts the GPRS packets coming from SGSN into appropriate PDP format (e.g., IP or X.25) and sends them out on the corresponding packet data network (PDN).

• It is connected to SGSNs via an IP GPRS backbone network • GGSN support routing functionality and manages information

for attached/detached procedures for GPRS users• GGSN performs mobility management functions requesting

location information from the HLR• GGSN is responsible for tunneling data, using GPRS Tunneling

Protocol (GTP), to encapsulate and de-capsulate packets for delivery to SGSN


SGSN FunctionsSGSN Functions

• SGSN is at the same hierarchical level as the MSC • SGSN responsible for the delivery of data packets from and to the

mobile stations (MSs) within its service area• It is responsible for mobility management

SGSN keeps track of the individual MS’s location, attached and detached procedure

Interaction with VLR/HLR• SGSN supports authentication and charging functions


PCU FunctionsPCU Functions

• GPRS radio resource allocation and management• GPRS radio connection establishment and management• Data transfer• Coding scheme selection• PCU statistics• Interface with Billing Center• It is possible that a single PCU (in this case known as PCU

Serving Node) interacts with different BSCs

PCU

BSC

BSC

PCUSNFrame RelayGb

Agprs

(Vendor defined)


GPRS Protocol Stack (MS-BSS-SGSN)GPRS Protocol Stack (MS-BSS-SGSN)•LLC provides six Service Access Points (SAPs) to the upper

layer protocols•SAPs act as tunnels to pass data between the layer 2 and layer

3 entities as follow: Four SAPs are dedicated to the Subnetwork-Dependent

Convergence Protocol (SNDCP) that manage data packet transmission

One SAP is dedicated to GPRS mobility management transmission One SAP is dedicated to SMS

•A Service Access Point Identifier (SAPI) identifies each SAP•A Data Link Connection Identifier (DLCI) identifies this logical

link•A DLCI is composed of the SAPI at the LLC and the TLLI•SAPIs are points at which the LLC provides access to the

SNDCP, that is Network SAPIs (NSAPIs)LLC

MS

LLC

SGSN

TLLISAPI 1

SAPI 2

NSAPI 1


GPRS Protocol Stack (MS-BSS-SGSN)GPRS Protocol Stack (MS-BSS-SGSN)

•The SAPIs that the LLC provides to the SNDCP layer are essentially the four QoS levels provided for data communications for different levels of reliability

• In wireless data transmission, the logical link connections are maintained even when the lower layer physical link no longer exist (mobile is in idle state)

Logical LinkEntity

SAPI=7Logical Link

EntitySAPI=11

Logical LinkEntity

SAPI=9Logical Link

EntitySAPI=5

Logical LinkEntity

SAPI=3

Logical LinkManagement

Entity Logical Link

EntitySAPI=1

GPRS Mobility Management

GMMGMM

SNDCP

QoS1 QoS2 QoS3 QoS4 SMS

SMS

Multiplexing Procedure

GRR BSSGP

LLC Layer

Layer 3

RLC/MAC Layer(Mobile Station)

BSSGPP(SGSN)


GPRS Protocol Stack (MS-BSS-SGSN)GPRS Protocol Stack (MS-BSS-SGSN)•The Logical Link management Entity (LLME) manages the

resources that have an impact on individual connections•One LLME exists per TLLI and provides the following functions

Initializing the parameters to be used Error processing Invoking connection flow control


GPRS Protocol Stack (MS-BSS-SGSN)GPRS Protocol Stack (MS-BSS-SGSN)•The SAPI parameter is in the address field of the LLC frame (4

bits)•The address field of the LLC frame is 1 octet (fixed)•There is a 3 octets (fixed) for frame check sequence (FCS)

SAPI

Address Field

Control FieldVariable

(max. 36 octets)

Variable Information Field

7 0

FCS3 octets

1 octet PD C/R

SAPI Description Type0001 GPRS Mobility Management GMM0011 User Data 1 QoS10101 User Data 2 QoS20111 SMS SMS1001 User Data 3 QoS31011 User Data 4 QoS4

Not in use


Required Changes in the Current GSM NetworksRequired Changes in the Current GSM Networks•GPRS is implemented on the top of GSM infrastructure by

adding two main network elements: Gateway GPRS support node (GGSN) Serving GPRS Support Node (SGSN)

• In addition to the new GPRS elements, existing GSM network elements should also be enhanced in order to support GPRS as follow: Base Station System (BSS): must be enhanced (software upgrade)

to recognize and send users data to SGSN that is serving the area. PCU interface is required to cater data traffic

Home Location Register (HLR): changes (software upgrade) should be made in HLR to register GPRS user’s profile and respond to queries originating from SGSN’s regarding these profiles

MSC/VLR: Existing hardware could be used but Software upgrade is required

•Mobile stations also need to be upgraded both in hardware and software to allow for multi-slot operation and variable coding


GPRS Physical ChannelsGPRS Physical Channels

•Radio channels of GPRS are same as GSM Same 200KHz Carrier Spacing Same Frame size 4.615ms 8 time slots per radio frame Same GMSK modulation as GSM

•More Flexible Resource Allocations: Adds 4 Channel Coding Modes/Schemes (CS1-CS4) Allows Flexible and independent time slot allocation (1-8) in the FW

and Rev links Radio resources shared dynamically between speech and data

services

Scheme Modulation Maximum rate[kb/s]

Code Rate

CS-4 17.6 1.0CS-3 14.8 / 13.6 0.80CS-2 11.2 0.66CS-1

GMSK

8.8 0.53


GPRS Logical ChannelsGPRS Logical Channels

Group Name Direction Function

PBCCH PBCCH Down-link Broadcast

PCCCH

PRACH Up-link Random AccessPPCH Down-link PagingPAGCH Down-link Access GrantPNCH Down-link Multicast

PTCHPDTCH Down & up-linkDataPACCH Down & up-linkAssociated ctrl


Packet Common Control Channels (PCCCHs)Packet Common Control Channels (PCCCHs)• Broadcast Channels:

Packet Broadcast Control Channels (PBCCH)– The PBCCH Transmits system information to all GPRS terminals in a cell

• Common Channels: Packet Random Access Channel (PRACH)

– is used by the MSs to initiate packet transfers or respond to paging messages.

– On this channel, MSs transmit access burst with long guard times. On receiving access bursts, the BSS assigns a timing advance to each terminal

Packet Paging Channel (PPCH) – is used to page an MS prior to downlink packet transfer

– ??The PPCH is used for paging both circuit-switched and GPRS services, depending on the network operation modes and the class of mobile. (Class A or B will support this functionality).

Packet Access Grant Channel (PAGCH)– is used in the packet transfer establishment phase to send resource assignment to an

MS prior to the packet transfer

– ??Additional resource assignment messages are also sent on a PCCH if the mobile is already involved in packet transfer.

Packet Notification Channel (PNCH) – is used to send a PTM multicast notification to a group of MSs prior to a PTM packet

transfer. The notification has the form of a resource assignment for the packet transfer


Packet Traffic Channels (PTCHs)Packet Traffic Channels (PTCHs)

•Packet Data Traffic Channel (PDTCH)

It is used for data transfer. It is dedicated temporarily to one or a group of mobiles for multicast applications.

More than one PDTCH can be used in parallel (multislot operation) for individual packet transfers. The PDTCH can be shared between many users (8/PDTCH)

•Packet Associated Control Channel (PACCH) It is used to convey signaling information related to a given MS such as

acknowledgements (ACK) and power control (PC) information. also carries resource assignment messages, either for allocation of a

PDTCH or further occurrences of a PACCH. One PACCH is associated with one or several PDTCHs concurrently

assigned to one MS

•Packet Timing Advance Control Channel (PTCCH) It is used in the uplink for transmission of random access burst. It

allows the timing advance required by the mobile in the packet transfer mode to be estimated.

In the downlink, the PTCCH can be used to update the timing advance to multiple mobiles.


Introducing GPRS in GSMIntroducing GPRS in GSM

•Two options are available for establishing GPRS air interface channels Option 1 uses the GSM signaling resources but establishes separate

packet data channels for traffic control. Traffic channels can be fixed or dynamic

Option 2 separates the GPRS resources entirely from those of GSM. There are several possible configurations with this option

– A PBCH can be used to carry GPRS-BCH information, common control channels, GPRS packet data channels, and traffic-associated channels

– If the packet data channels are not carried by the PBCH or if additional PDCH resources are required, separate timeslots can be configured


Mixing or Separating PCCCH & CCCH Mixing or Separating PCCCH & CCCH •When no PCCCH is allocated in a cell, all GPRS attached MSs

automatically camp on the existing GSM CCCH as they do in the idle state

•The allocation of a PCCCH is the result of either an increased demand for packet data transfer or whenever there are enough physical channels in a cell

• If the network releases the PCCCH, the MSs return to the CCCH


GPRS Air Interface ProtocolGPRS Air Interface Protocol

•A physical channel dedicated to packet traffic channel is called packet data channel (PDCH)

•The allocation of TCHs and PDCHs is done dynamically according to the “capacity on demand” principle

•A GPRS cell may have one or more PDCHs allocated from channels otherwise used as traffic channels (TCH)

•The Master Slave Concept At least one PDCH (mapped on one physical time slot) acts as a

master The master accommodates packet common control channels

(PCCCHs) carrying control signaling for initiating packet transfer as well as user data and dedicated signaling.

The other channels, acting as slaves, are only used for user data transfer.

•The existence of PDCHs does not imply the existence of PCCCH


• The number of allocated PDCHs in a cell can be increased or decreased according to demand Load supervision is done in the MAC layer to monitor the load on the

PDCHs Unused TCHs can be allocated as PDCHs to increase the overall QoS

for GPRS. If services with higher priority request resources, reallocation of PDCHs can take place

This concept is used in cells with few or not GPRS users without the need for permanently allocated resources

Capacity on DemandCapacity on Demand


Mapping GPRS Packets to GSM BurstsMapping GPRS Packets to GSM Bursts

PH User data

Segment

FH Info FSC

BH Info BSC Tail

Convolutional encoding

Burst Burst Burst Burst

Segment

Segment

Packet (N-PDU)

LLC Frame

RLC Block

Normal burst

PH: Packet headerFCS: Frame check sequenceFH: Frame header BSC: Block check sequence BH: Block header

Network Layer

SNDCP Layer

LLC Layer

RLC/MAC Layer

Physical Layer

456

114

Data Block

SegmentSegment

114 114 114


Packet Data Channel in GPRSPacket Data Channel in GPRS

0 1 2 3 4 5 6 70 1 2 3 4 5 6 70 1 2 3 4 5 6 70 1 2 3 4 5 6 7

TDMA frame

Radio Block

456 bits

MAC Hdr RLC HdrRLC Data

(size depending on coding scheme) BC

S

Coding/puncturing

PDCH0PDCH1

12 block structure (52 TDMA frames)

Idle burst


MS BSS

Packet channel requestPRACH or RACH

Packet immediate assignmentPAGCH or AGCH

Packet resource requestPACCH

Packet resource assignmentPACCHRandom access

Transmission

Frame transmissionPDTCH

Negative acknowledgementPACCH

Retransmission of blocks in errorPDTCH

AcknowledgementPACCH

Random Access & Uplink Data TransmissionRandom Access & Uplink Data Transmission


Packet paging requestPPCH or PCH

Packet channel requestPRACH or RACH

Packet immediate assignmentPAGCH or AGCH

Packet paging responsePACCH

Packet resource assignmentPACCH or PAGCH or AGCHPaging

Transmission

Frame transmissionPDTCH

Negative acknowledgementPACCH

Retransmission of blocks in errorPDTCH

AcknowledgementPACCH

Packet paging & Uplink Data TransmissionPacket paging & Uplink Data Transmission

MS BSS


TS1

TS1

TS0

TS0

R 1 1 PUA(2) 2

1 Dt(3) 1 Dt(3)

PCR(2) Dt(1) Dt(1) Dt(2)

BSS

MS2

PCR

PUA

Dat

a

Dt(1) Dt(1)

1 Dt(3)

Dt(1)

2 Dt(3)

Dt(2)

1 1 Ack(2)

Dt(1)

Ack

1 Dt(3)

Dt(1)

Downlink

Uplink

Uplink state flag(MS allowed on uplink block)

Message type (downlink)and target MS

PCR: Packet channel request (PRACH) Ack: Packet uplink ack/nack (PACCH) Dt: Data block

PUA: Packet uplink assignment (PAGCH) PCA: Packet control acknowledgment

Dynamic Allocation of Time Slots (Example)


Routing Areas and Location AreasRouting Areas and Location Areas

•One LA consists of a number of cells belonging to BSCs that are connected to the same core network node

•One RA consists of a number of cells belonging to BSCs that are connected to the same core network node

•One LA is handled by only one core network serving node (one combined MSC+SGSN)

•One RA is handled by only one core network serving node (one combined MSC+SGSN)

•The GSM/GPRS defined relations between LA and RA as follow: RA and LA is equal in hierarchical level One RA is a subset of one, and only one LA, meaning that a RA do

not span more than on LA

CellRA

CellRA

LA


GPRS IdentitiesGPRS Identities

• International Mobile Subscriber Identity (IMSI)•Packet Temporary Mobile Subscriber Identity (P-TMSI)•Temporary Logical Link Identity (TLLI)

It is an identifier that uniquely identifies an MS within a routing area Local TLLI (derived from P-TLLI), Random TLLI (generated by MS), Foreign TLLI (derived from Local TLLI)

•Network layer Service Access Point Identifier (NSAPI)•Tunneling Identity (TID which is =IMSI+NSAPI)•PDP address (IPv4/6, X.25,…)•Routing Area Identity (RAI which is =MCC+MNC+LAC+RAC)•GSN address

GSN number (SS7 network), GSN address (IP address/logical name)

•Access Point Name (APN) DNS name of GGSN=route to external network


PDP Context and Session ManagementPDP Context and Session Management•After GPRS attachment, to exchange data packets with

external PDNs, the mobile must apply for one or more address used in the PDN: An IP address in case of the IP networks This is called a Packet Data Protocol address (PDP address)

•For each session a PDP context is created describing its characteristics and includes: PDP type (IPv4, etc) PDP address (172.129.23.10) Requested QoS The address of the GGSN that serves as the access point to the PDN

•The PDP context is stored in the following nodes: MS SGSN GGSN


PDP Address AllocationPDP Address Allocation

•PDP address allocation can be: Static: User’s home PLMN network operator assigns a permanent

PDP address to the user Dynamic: A PDP address is assigned to the user upon activation of a

PDP context, this can be assigned by:– Home PLMN (dynamic home PLMN PDP address)

– Visited PLMN (dynamic visited PLMN PDP address)

– The home PLMN decides which alternative is used

• In the case of dynamic PDP address, the GGSN is responsible for the allocation and activation/deactivation of PDP address


PDP Context ActivationPDP Context Activation

MS BSS SGSN GGSN

GGSN

Um

1. Activate PDP Context

2. Create PDP Context Request

3. Create PDP Context Response

4. Activate PDP Context Accept

Gb

Gn

Gn


Functional PDP State ModelFunctional PDP State Model

INACTIVE

ACTIVE

Activate PDPContext

Deactivate PDP Contextor

MM state change to IDLEor PMM-DETACHED


Definition of PDP StatesDefinition of PDP States

•A GPRS subscription contains the subscription of one or more PDP addresses

•Each PDP address is described by one or more PDP contexts in the MS, SGSN and GGSN

•Each PDP context may be associated with a Traffic Flow Template (TFT)

•Every PDP context exists independently in one of two PDP states: Inactive: The data service for a certain PDP address of a subscriber

is not activated Active: The PDP context for that address in use is activated in MS,

SGSN and GGSN


GPRS Network AccessGPRS Network Access

•Once a GPRS MS has begun operation, it introduces itself to the network by sending a “GPRS attach” request

•Network access can be achieved from either fixed side or the mobile side of the GPRS network by making PTP and PMP available

•As is cellular networks, several administrative functions are performed to validate user, including; User Registration

– Associates the mobile ID with user’s PDP (Packet Data Protocol) and address with in PLMN. Within the home area of the MS, traditional HLRs are enhanced to reference GPRS data. Outside the home area, dynamically allocated records are referenced in VLRs.

Authentication– Ensures the availability of GPRS MS and its associated services. GMM

protocol (Mobility Management) functions are used for this part of signaling.

CAC (Call Admission Control)– it determines the required network resources for the QoS that is

requested. It these resources are available, they will be reserved.


GPRS AttachGPRS Attach

•Network can/should check MS’s identity•Download MS’s subscription information from HLR to SGSN (if

SGSN doesn’t already have that info)•Update MSC/VLR (if IMSI Attach is also performed)•Attach types

Attach the first time Attach again in the same SGSN Attach again in a new SGSN Attach when SGSN has detected the context


GPRS Attach Procedure (1)GPRS Attach Procedure (1)

•The request for a GPRS attach is made to the SGSN •Mobile sends SGSN its identity as an IMSI (international mobile

subscriber identity) or P-TMSI (packet temporary mobile subscriber identity), this message will also contain a: Network Service Area Point Identifier (NSAPI), which is specific to a

particular network application at the mobile station. SNDCP layer uses this to communicate with the network applications (Internet browser, email, etc have their own NSAPI)

•The latter indicates to the SGSN whether the mobile wants to attach as a GPRS device, a GSM device, or both

•The SGSN will attach the mobile and inform the HLR if there has been a change in the RAI, if the desired attach type is both GPRS and GSM, the SGSN will also update the location with the VLR, provided that the Gs interface exists

•Note that a GPRS attach does not enable the mobile phone to transmit and receive data, for this, the mobile has to activate a communication session using PDP context


GPRS Attach Procedure (2)GPRS Attach Procedure (2)

•After authorization, the SGSN sends back a reply to the mobile station with a Temporary Logical Link Identifier (TLLI)

•The TLLI is specific to the mobile and is used by the LLC layer to provide a temporary ID to the mobile station, which can be used for a data communication

•A database is maintained at the SGSN that maps the mobile identity with the TLLI assigned to it, the NSAPI is associated with and the QOS subscription parameters required by the application

MS1 TLLI=1, NSAPI=2

MS2 TLLI=2, NSAPI=3

MS3 TLLI=3, NSAPI=2

More files tocome afteractivation

Table update example for SGSN with 3 attached users


GPRS Attach ProcedureGPRS Attach Procedure

1. Attach Request

2. Security Procedures

2. Security Procedures

3. Location Update

4. Location Update

5. Attach Accept

MS BSS SGSNUm Gb VLR

Gs

VLRMAP


GPRS Detach Procedure (1)GPRS Detach Procedure (1)

•GPRS detach procedure allows: MS to inform the network that it does not want access the SGSN-

based services any longer The network to inform the MS that it does not have access to the

SGSN-based service anymore

•Different types of detach are: IMSI detach GPRS detach combine GPRS/IMSI detach (MS initiated only)


GPRS Detach Procedure (2)GPRS Detach Procedure (2)

•There two different ways for detaching a MS: Explicit: The network or the MS explicitly requested detach

– A Detached Request is sent by the SGSN to the MS, or by the MS to the SGSN

Implicit: The network detached the MS without notifying the MS

•The MS can make an IMSI detach in one of two ways depending on if it is GPRS-attached or not: A GPRS-attached MS sends a Detached Request message to SGSN,

indicating and IMSI detach A MS that is not GPRS-attached makes the IMSI detach as already

defined in GSM

• In the network-originated Detach Request message there may be an indication to tell the MS that it is requested to initiate GPRS attach and PDP context activation procedure for the previously activated PDP contexts


Mobility Management Main IssuesMobility Management Main Issues

•The main task of mobility management is to keep track of the user’s current location, so that in coming packets can be router to his/her MS

•The main issues in mobility management are as follow: READY timer function Periodic RA update timer function Mobile reachable timer function


Mobility ManagementMobility Management

•As a mobile station moves from one area to another, mobility management functions are used to track its location within each PLMN

•The mobile station's profiles are preserved in the VLRs that are accessible to SGSNs via the local MSC

•A logical link is established and maintained between the mobile station and the SGSN at each PLMN

•At the end of transmission or when a mobile station moves out of the area of a specific SGSN, the logical link is released and the resources associated with it can be reallocated


Mobility Management-MS StateMobility Management-MS State

• IDLE: The subscriber is not attached to the GPRS MM

•STANDBY: The subscriber is attached to the GPRS MM

•READY: The SGSN MM context extended by location information for the subscriber on cell level

IDLE

STANDBY

READY

GPRS Detach GPRS Attach

PDU Transmission

READY timer expiryorForce STANDYBY

MM State model of MS


Mobility Management-SGSN Model stateMobility Management-SGSN Model state

•This function of Mobility Management (MM) is needed in GPRS to Attach: know who is the MS and what it can or is allowed to do. Detach: leaving the system Location update: know the location of MS

IDLE

STANDBY

READY

GPRS Detach or Cancel location

GPRS Attach

PDU reception

READY timer expiryor

Force STANDYBY

Implicit Detachor

Cancel Location

MM State Model of SGSN

• In the STANDBY state the subscriber is known in the accuracy of the RA• In the READY state the subscriber is know in the accuracy of the LA (cell)


Mobility Management- RA and LA UpdateMobility Management- RA and LA Update• Interaction between SGSN and MSC/VLR

IMSI attached and detached via SGSN Co-ordination of LA update and RA update, including periodic

updates Paging for a CS connection via the SGSN Alert procedures for non-PS services Identification procedure MM information procedure


Routing and Data TransferRouting and Data Transfer

•Once a mobile station begins data transmission, routing is performed by the GSNs on a hop-by-hop basis through the mobile network using the destination address in the message header

•Routing tables are maintained by the GSNs utilizing the GTP layer which may carry out Address Translation and Mapping functions to convert the external PDN addresses to an address that is usable for routing within PLMNs.

•The data itself will go through several transformations as it travels through the network

•Depending on the destination PDN, the data can be: Forwarded, using the relay function, to go from one node to the other in

the route, Tunneled to transfer data from one PLMN to another, Compressed to use the radio path in an efficient manner (Compression

algorithms may be used for manufacturers to differentiate themselves, however, they may face interoperability issues in heterogeneous networks), and/or

Encrypted to protect the mobile station from eavesdropping (Encryption algorithms can also be used as a differentiating factor).


Location Management-Routing Area UpdateLocation Management-Routing Area Update•When MS changes RA

It tells to the network (old RA) it came from MS doesn’t know if SGSN changes

– Simple update , if same SGSN handles both RA’s

– If SGSN changes, then– get MS’s active information from the old SGSN– new SGSN needs to get user’s subscription information from HLR– all GGSN’s must be updated

•MS detects RA change but not SGSN changes• Intra-SGSN routing area update

No need to update HLR or GGSN

• Inter-SGSN routing area update Both HLR and GGSN need to be updated


BSC

SGSN

GGSN

BTS

IP

I want to do packet

Radio link established

Set up a contextTunnel created

IP Address exists!HLR

MSC

GMSC

Session Setup Example

PSTN/ISDN


GMSC

MSC

BSC

GGSN

SGSN

PSTN/ISDN

BTS

IP

163.43.42.143

Inbound packet

Allocate a few bursts and send it!

This tunnel!

This radio link!

Where is the mobile?

?

Where is the mobile?

?

HLR

Packet Forwarding Example


GMSC

MSC

BSC

GGSN

SGSN

PSTN/ISDN

BTS

IP

Tunnel createdRadio link establishedI’m here now

OK, new link and tunnel

Still same IP address!HLR

RA Reselection Example

PSTN/ISDN


GSM/GPRS Link Budget Comparison (1)GSM/GPRS Link Budget Comparison (1)•The Receiver Sensitivity depends on the coding scheme

Each type of modulation and coding scheme requires, for a given BLER, different minimum Eb/No

As the data rates increases the error protection is reduced and therefore more Eb/No is required to meet the same BLER, this translates into different receiver sensitivities associated to each coding scheme

•There is smaller or no body loss The typical 3 dB body loss associated with voice service is excluded

from the GPRS link budget (the user does not use the MS close to his/her head)

Due to this 3 dB, the cell radius for CS1 (CS2) is larger (equal) than for voice service


GSM/GPRS Link Budget Comparison (2)GSM/GPRS Link Budget Comparison (2)•The Down-link Interference Level Increase

The effect of GPRS load on the existing GSM service will be of the order of up to 2dB degradation in the down-link TCHs

– Since down link GPRS power control will not be used, extra load is anticipated that will increase the interference level when GPRS services are introduced

No effect is anticipated on the down-link BCCH– Permanently keyed carriers and the absence of down-link power control

serve to keep the interference at a fixed amount

Power control is implemented in the up-link case, hence, the effect of the GPRS traffic is not a problem and there is no differences between BCCH and TCH cases

•Different Coding Schemes can be used in different parts of markets depending on The future demand for the data rates and marketing strategies The ability to offer different coding schemes without (or the

minimum) modification in the existing network


GSM/GPRS Link Budget Promoters (Examples)GSM/GPRS Link Budget Promoters (Examples)

Service QoS Required C/N BS Sensitivity for TalkFamily (NOKIA)

Speech BLER < 8% 6.0 dB -108 dBmCS1 BLER < 10% 6.2 dB -107.8 dBmCS2 BLER < 10% 9.8 dB -104.1 dBmCS3 BLER < 10% 12 dB -102.0 dBmCS4 BLER < 10% 19.3 dB -94.7 dBm

Service Speech CS1 CS2 CS3 CS4Required C/N 6.0 dB 6.2 dB 9.8 dB 12.0 dB 19.3 dBBTS sensitivity -108 dBm -107.8 dBm -104.1 dBm -102.4 dBm -94.7 dBmBody Loss 3 dB 0 dB 0 dB 0 dB 0 dBLink Budget difference related toSpeech service

+2.8 dB -0.8 dB - 3.0dB -10.3dB

Receiver Sensitivity Effect

Body Loss Effect


Coding Schemes and Coverage ImpactCoding Schemes and Coverage Impact

A Review of UMTSA Review of UMTS


“UMTS will be a mobile communications system that can offer significant user benefits including high-quality wireless multimedia services to a convergent network of fixed, cellular and satellite components.

It will deliver information directly to users and provide them with access to new and innovative services and applications.

It will offer mobile personalised communications to the mass market regardless of location, network and terminal used”.

UMTS Forum 1997

UMTS Goals


Global

Suburban

Macro-Cell

Urban

Micro-Cell In- Building

Pico-Cell

Home-Cell

UMTS Vision


UMTS Bearer ServicesUMTS Bearer Services

•The UMTS radio access network and fixed network are expected to provide four classes of bearer services:

Class A - Circuit-switched bit pipe

Class B - Circuit-switched bit pipe for variable bit rate

Class C - Connection-oriented packet switched bearer service

Class D - Connectionless packet switched bearer service


Minimum bearer capabilities for UMTS

Real Time/ Constant Delay Non Real Time/ Variable DelayOperating environment Peak Bit Rate BER / Max

Transfer DelayPeak Bit Rate BER / Max

Transfer DelayRural outdoor(terminal speed up to500 km/ h)

144 kbit/s

granularity 16kbit/s

BER 10-3 (20 ms )BER 10-7 (300ms)

144 kbit/s BER = 10-5 to 10-8

Max Transfer Delay150 ms or more

Urban/ Suburbanoutdoor(Terminal speed up to120 km/ h)

512 kbit/s


BER 10-3 (20 ms)BER 10-7 (300 ms)

512 kbit/s BER = 10-5 to 10-8


Indoor/ Low rangeoutdoor(Terminal speed up to10 km/ h)

2 Mbit/s


delay 20 - 300 msBER 10-3 (20 ms)BER 10-7 (300 ms)

2 Mbit/s BER = 10-5 to 10-8


Both Real-Time and Non-Real-Time cases may include packet or circuit type of connectionsSpeech bearers shall be supported in all operating environments

UMTS Services Capabilities


Migration Approach to UMTSMigration Approach to UMTS

•Europe has decided to adopt an evolutionary approach for the UMTS core network based on migration from the GSM/GPRS infrastructure

•For the actual air interface, a revolutionary approach has been chosen. That is a new radio air interface for UMTS Terrestrial Radio Access (UTRA)

•There are two other parallel activities concerning the UMTS air interface, both using an evolutionary approach (an intermediate approach)


Evolution approach based on GSM Infrastructure

GSM

DCS-1800

PCS-1900

DECT

TETRA

HIPERLAN

SATELLITE

IS-54

IS-95

PACS

PDC

PHS

Evolved

GSM

Air Interface

New

Air Interface

NSS

and/or

BSC

PSTN

N-ISDN

CSPDN

PSPDN

B-ISDN

Air Interface GSM Infrastructur

e

Public Network

Multi-mode Dual-mode

Dual-mode

Migration Approach to UMTS


UMTS NetworkUMTS Network

GMSC

MSC

UTRAN

BSC

GGSN

SGSN

PSTN/ISDN

UTRAN: UMTS Terrestrial Radio Access NetworkRNC: Radio Network Controller

Node B

CS core network

UTRAN transport: ATMNew tricks: Soft Handover using IP

IP

Packet core network

HLR


UTRAN ArchitectureUTRAN Architecture

RNS

RNC

RNS

RNC

Core Network

Node B Node B Node B Node B

Iu Iu

Iur

Iub IubIub Iub

RNS: Radio Network Subsystem (BSS)RNC: Radio Network Controller (BSC)Node B: “Logical node for radio Tx/Rx in one or more

cells to/from UE” (BTS)


General Protocol ArchitectureGeneral Protocol Architecture

U T R A NU E C NA c c e s s S tra tu m

N o n -A c c e s s S tra tu m

R a d io(U u )

Iu

R a d iop ro to -c o ls(1 )

R a d iop ro to -c o ls(1 )

Iup ro toc o ls(2 )

Iup ro toc o ls(2 )

Iu and Uu user plane

The Radio Access bearer service is offered from SAP to SAP by the Access Stratum


Overall Protocol StructureOverall Protocol Structure

Network Layer (L3):

- Partitioned into Control (C-) Plane & User (U-) Plane.- Sublayer RRC interfaces with layer-2 and terminates @ UTRAN.- Sublayer “Duplication Avoidance” Terminates @ CN

Data Link Layer (L2):

- Partitioned into 4 sublayers,(I) Medium Access Control (MAC)(II) Radio Link Control (RLC)(III) Packet Data Convergence Protocol (PDCP) (IV) Broadcast/Multicast Control (BMC)

Physical Layer (L1):

- Partitioned to several Physical & Transport channels


Radio Interface Protocol ArchitectureRadio Interface Protocol Architecture

RadioInterfaceProtocol

Architecture

Transport Channel (SAP)

Physical Channels

Logical Channel

L3

cont

rol

cont

rol

cont

rol

cont

rol

LogicalChannels

TransportChannels

C-plane signalling U-plane information

PHY

L2/MAC

L1

RLC

DCNtGC

L2/RLC

MAC

RLCRLC

RLCRLC

RLCRLC

RLC

Duplication avoidance

UuS boundary

BMC L2/BMC

RRC

control

PDCPPDCP L2/PDCP

DCNtGC


Channel DefinitionsChannel Definitions

Transport Channel:

“…the services offered by Layer 1 to higher layers”Transport channel defines the method and the characteristics by which data are transferred over the air-interface

Physical Channel:

Physical channel, usually consisting of radio Frames and timeslots, is the mechanism with which the data are transferred over the physical resources such as code, frequency, phase and time.

Logical Channel:

MAC layer provides data transfer services on Logical channels


Logical Channel StructureLogical Channel Structure

S y n c h r o n i s a t i o n C o n t r o l C h a n n e l ( S C C H )

B r o a d c a s t C o n t r o l C h a n n e l ( B C C H )

P a g i n g C o n t r o l C h a n n e l ( P C C H )

D e d i c a t e d C o n t r o l C h a n n e l ( D C C H )D e d i c a t e d C o n t r o l C h a n n e l ( D C C H )C o m m o n C o n t r o l C h a n n e l ( C C C H )

C o n t r o l C h a n n e l ( C C H )

D e d i c a t e d T r a f f i c C h a n n e l ( D T C H )T r a f f i c C h a n n e l ( T C H )

O D M A D e d i c a t e d C o n t r o l C h a n n e l ( O D C C H )

O D M A C o m m o n C o n t r o l C h a n n e l ( O C C C H )

O D M A D e d i c a t e d T r a f f i c C h a n n e l ( O D T C H )

C o m m o n T r a f f i c C h a n n e l ( C T C H )

S h a r e d C h a n n e l C o n t r o l C h a n n e l ( S H C C H )

(TDD)

(ODMA)

(ODMA)

(TDD)


Transport ChannelsTransport Channels

Common Transport Channel

Common Transport Channels require inband identification of the UEs when addressing particular UEs.

Dedicated Transport Channels:

Dedicated Transport Channels require the UEs to be identified by the physical channel , i.e. code and frequency for FDD (code, frequency and timeslot for TDD).



BroadcastChannel (BCH)(Downlink)

Transport Channels

Common ChannelsDedicated Channels

Downlink SharedChannel(DSCH)(Downlink)

Common PacketChannel (CPCH)(Uplink)

Forward-Access

Channel (FACH)(Downlink)

Paging

Channel (PCH)(Downlink)

Random-Access

Channel (RACH)(Uplink)

Dedicated Channel (DCH)

(Down & uplink)

Fast uplink SignalingChannel (FAUSCH)(Uplink)



Common Transport Channels BCH: The Broadcast Channel (BCH) is a downlink transport channel that is used

to broadcast system- and cell-specific information. The BCH is always transmitted over the entire cell with a low fixed bit rate.

FACH: The Forward Access Channel (FACH) is a downlink transport channel. The FACH is transmitted over the entire cell or over only a part of the cell using

beam-forming antennas. The FACH uses slow power control.

PCH: The Paging Channel (PCH) is a downlink transport channel. The PCH is always transmitted over the entire cell. The transmission of the PCH is associated with the transmission of a physical layer signal, the Paging Indicator, to support efficient sleep-mode procedures.

RACH: The Random Access Channel (RACH) is an uplink transport channel. The RACH is always received from the entire cell. The RACH is characterised by a limited size data field, a collision risk and by the use of open loop power control.



Common Transport Channels CPCH: The Common Packet Channel (CPCH) is an uplink transport channel.

The CPCH is a contention based random access channel used for transmission of bursty data traffic. CPCH is associated with a dedicated channel on the downlink which provides power control for the uplink CPCH.

DSCH: The downlink shared channel (DSCH) is a downlink transport channel shared by several Ues. The DSCH is associated with a DCH.

Dedicated Transport Channel DCH: The Dedicated Channel (DCH) is a downlink or uplink transport channel.

The DCH is transmitted over the entire cell or over only a part of the cell using beam-forming antennas. The Dedicated Channel (DCH) is characterised by the possibility of fast rate change (every 10ms), fast power control and inherent addressing of UEs.


Logical onto Transport Channel MappingLogical onto Transport Channel Mapping

BCH PCH DSCHFACHRACH DCH

BCCH-SAP

SCH(TDD only)

DCCH-SAP

CCCH-SAP

PCCH-SAP

SCCH-SAP

DTCH-SAP

TransportChannels

MAC SAPs

FAUSCH USCH(TDD only)

CPCH(FDD only)

CTCH-SAP

SHCCH-SAP(TDD only)

Logical Channel Mapping onto Transport Channels (UE side)

BCH PCH DSCHFACHRACH DCH

BCCH-SAP

DCCH-SAP

CCCH-SAP

PCCH-SAP

SCCH-SAP

DTCH-SAP

TransportChannels

MAC SAPs

FAUSCHSCH(TDD only)

USCH(TDD only)

CPCH(FDD only)

CTCH-SAP

SHCCH-SAP(TDD only)

Logical Channel Mapping onto Transport Channels (UTRAN side)


Physical Channels (Uplink)Physical Channels (Uplink)

Uplink Physical Channels

Common Physical ChannelsDedicated Physical Channels

Dedicated Physical Data Channels(Uplink DPDCH)

Dedicated Physical Control Channel(Uplink DPCCH)

Physical Random Access Channel (PRACH)

Physical Common Packet Channel (PCPCH)


Physical Channels (Downlink)Physical Channels (Downlink)

Common Pilot Channel(CPICH)

Primary CPICH

Downlink Physical Channels

Common Physical ChannelsDedicated Physical Channels

Secondary CPICH

Primary Common ControlPhysical Channel

(P-CCPCH)

Secondary Common ControlPhysical Channel

(S-CCPCH)

SynchronisationChannel

(SCH)

Physical Downlink Shared Channel

(PDSCH)

Acquisition IndicationChannel(AICH)

Page IndicationChannel(PICH)

Dedicated Physical Control Channel (DPCCH)

Dedicated Physical Data Channel (DPDCH)

TMUX


Physical onto Transport Channel Mapping Physical onto Transport Channel Mapping

Transport Channels

DCH

RACH

CPCH

BCH

FACH

PCH

DSCH

Physical Channels

Dedicated Physical Data Channel (DPDCH)

Dedicated Physical Control Channel (DPCCH)

Physical Random Access Channel (PRACH)

Physical Common Packet Channel (PCPCH)

Common Pilot Channel (CPICH)

Primary Common Control Physical Channel (P-CCPCH)

Secondary Common Control Physical Channel (S-CCPCH)

Synchronisation Channel (SCH)

Physical Downlink Shared Channel (PDSCH)

Acquisition Indication Channel (AICH)

Page Indication Channel (PICH)

CPICH (P&S), AICH, DPCCH & PICH used for L1 signaling


Physical Channels (Uplink)Physical Channels (Uplink)

DPDCH: Dedicated Physical Data ChannelDPCCH: Dedicated Physical Control Channel

DPDCH - Carries dedicated transport channels

DPCCH - Carries control information at layer 1 (known pilot, transport format combination indicator (TFCI), feedback information (FBI) and transmit power control (TPC) command)

DPCH

Dedicated Physical Channels (DPCH)


Iu Interface

Iu-PS

AAL5

ATM

UDP/IP

GTPUser plane

AAL5

ATM

UDP/IP

GTPUser plane

• UTRAN shall support two logically separate signaling flows via Iu to combined or separate network nodes of different types (MSC and SGSN);

• the protocol architecture for the User Plane of the Iu interface towards the IP domain shall be based on the same principles as for the (evolved) Gn interface;

• One or several AAL5/ATM Permanent VCs may be used as the common L2 resources between the UTRAN and the ‘IP domain’ of the CN.

Protocol architecture for the Iu user plane toward the IP domain


Iu User Plane

RLC

MAC

L1

GTP-U

BSSGP

ATM

L2

L1

UDP/IP

L2

L1

UDP/IP

Uu Iu Gn GiUE RNS 3G-SGSN 3G-GGSN

GTP-UGTP-U

UDP/IP

RLC

L1

AAL5

ATM

UDP/IP

GTP-U

MACAAL5

• the standard shall support that the user data flows transported over the Iu reference point to/from the ‘IP domain’ shall be multiplexed on top of common L2 resources;

• if the Iu data transport bases on ATM PVCs then the Iu IP layer provides the Iu network layer services;

• a tunneling protocol is used on top of the common L2, this tunneling protocol corresponds to an evolution of the user plane part of the GTP protocol used in GPRS put on top of UDP/IP;

• the user data plane in the UMTS network is made up of two tunnels: a first IP/UDP/GTP tunnel between RNC and 3G SGSN on Iu; a second IP/UDP/GTP tunnel between GGSN and 3G SGSN on Gn.


GTP-u

AAL5

IP

UDP

ATM

GTP-u

L2

IP

UDP

L1

SRNC 3G-SGSN 2G-SGSN

GTP-u

L2

IP

UDP

L1

GTP-u

AAL5

IP

UDP

ATMIu Gn

User Plane Protocol Stack for Data Retrieve Between GPRS and UMTS


User Plane Protocol Stack for Data Retrieve in UMTS

GnIu Iu

GTP-u

AAL5

IP

UDP

ATM

L2

IP

L1

GTP-u

AAL5

IP

UDP

ATM

SourceSRNC

3G-SGSN 3G-SGSN TargetSRNC

L2

IP

L1

AAL5

IP

ATM

AAL5

IP

ATM


Two Iu signalling connections (“two RANAP instances”)

UTRAN

3G SGSN

HLR

3G MSC/VLR

UE

CS servicedomain

Two CN service domains

One RRC connection

UTRAN withdistributionfunctionality

PS servicedomain

Common subscription data base

CS state PS state

PS state CS state

CS location PS location

Separate Core Network Architecturefor UMTS


Integrated Core Network Architecturefor UMTS

Two Iu signalling connections “two RANAP instances”

UTRAN

HLR

UMSC

UE

CS servicedomain

Two CN service domains

One RRC connection

UTRAN withdistributionfunctionality

PS servicedomain

Common subscription data base

CS state PS state

PS state CS state

CS location PS location


Packet Data Network with Various Radio TechnologiesPacket Data Network with Various Radio Technologies

ISP

Intranet

InternetGGSN

PSTNSGSN-GSM

W-LAN

SGSN-W-LAN

URAN SGSN-UMTS

PSTNGW

IP - backbone

Modular, main parts are independent of radio access

SGSN-D-AMPS

GGSN-corporate

IS-136

BSS


Common architecture 2005Common architecture 2005

3G Network based on the same Server/Gateway architecture for wireline & for wireless

Backbone

MGW MGW

Wireless Wireline

Media Gateway


Toward an All-IP NetworkToward an All-IP Network

RNCUTRANSG

MGSSP

SGSN

GGSN MG

MSCServer

SSP SCF

SSP

CSCF

SCF

MGCFSG

MGPSTN

PDN

IP Backbone

Third Party Service Provider

Service EnvironmentHome Network

Signaling Interface

Data Interfaces


Toward All-IP ConceptToward All-IP Concept

Servers

Clients

IP Backbone Network

AccessAccess

FutureMulti-service networks

Communcationi Control

Content Content

Access

Clients

TodaySingle-service networks

LA

N (

Dat

a)L

AN

(D

ata)

Mo

bile

Mo

bile

Fix

ed T

elep

ho

ny

Fix

ed T

elep

ho

ny

Bro

adb

and

Wir

eles

sB

road

ban

dW

irel

ess

Services

WLAN Integration, the First Step toward 4G

WLAN Integration, the First Step toward 4G


Evolution Toward Advanced ServicesEvolution Toward Advanced Services

2GVoice

GSM, IS-95

2.5GVoice + Data services

GPRS, EDGE

3GVoice + Broadband Data services

UMTS, cdma2000

Cellular

802.11bUp to 11 Mbps2.4 GHz Band

802.11a/Hiperlan IIUp to 54 Mbps5 GHz Band

Wireless LANS

QoS Multi-services

But what will fuel the revenue growth?


Motivation for 3G-WLAN IntegrationMotivation for 3G-WLAN Integration• 3G technologies may not meet be a real solution for high bit

rates It will be expensive Planning picocell networks has several technical issues

• WLANs are capable of providing “real” high bit rate and: They are cheaper to manufacture They are cheaper to purchase They are cheaper to deploy They are cheaper to operate

• New revenue streams Corporate customers becomes more mobile Consumer customers become more demanding


Potential Operational ModelsPotential Operational Models

• Cellular operators expands their network and cover the hot spots as a part of their network by WLAN Pros: Good operational experience and more capital Cons: Need to add several new classes of equipment into

their network

• Infrastructure owners deploy and leases access to the operators Pros: They have already access to the customers Cons: New in this business

• ISPs or another third party acts as a reseller


Interworking SolutionsInterworking Solutions

• No Coupling Independent 3G and WLAN networks, independent data and

control paths Independent AAA functions

• Loose Coupling Independent 3G and WLAN data paths Using 3G AAA functions

• Tight Coupling WALN acts as an integrated part of 3G


Interworking ChallengesInterworking Challenges

• Mobility Management Vertical handoffs

• Authentication/Authorization/Accounting (AAA) Identification Billing mechanisms

• Quality of Service How to map the services between cellular and WLAN

networks? How to maintain the QoS between networks


Why Cellular Why Cellular Operators need need WLAN?WLAN?

Why Cellular Why Cellular Operators need need WLAN?WLAN?

Operators need more bandwidth (or at least they think)

WLAN radio technologies provide superior bandwidth

And It is cheaper to manufacture It is cheaper to purchase It is cheaper to deploy It is cheaper to operate


Design Objectives

Operators should maintain compatibility with GSM/GPRS/UMTS core network roaming and billing functions

A GSM Subscriber Identity Module (SIM) is a natural choice for WLAN subscriber management

In the first phase the focus of the WLAN business will be wireless data The system should be optimized for terminal initiated IP data services

To minimize complexity and cost, the WLAN system must utilize the existing GPRS billing system


Combined Cellular/WLAN ArchitectureCombined Cellular/WLAN Architecture

10/100 Base-T Operator

Core IPMobility

Router/Switch

CellularCore

GGSN

SGSN

BSC

SS7

MSC/HLR

GPRSChargingGateway

AuthenticationServer

(Access Controller)

Intra-SystemHandoff

Inter-SystemHandoff


Authentication ProcedureAuthentication Procedure

Operator Core IP

Mobility Router/Switch

Public WLAN

GPRS RAN

CellularCore

GGSN

SS7

MSC/HLR


(Access Controller)SIM

1) Terminal authentication through WLAN (SIM)

2) SIM authentication and user accounting through IP

3) GSM authentication andcharging messaging

SGSN


Main ChallengesMain Challenges

Standard GSM subscriber authentication signaling from the terminal to the cellular modules must go through IP based networks

In the combined scenario, voice and data, handoff scenarios between WLAN and WWAN is not clear and defined


WLAN Elements in WLAN Elements in Cellular Systems SystemsWLAN Elements in WLAN Elements in Cellular Systems Systems

Mobility Router/Switch

(Access Controller)


RADIUS

MAP

MSC HLR

Access Operator Cellular Operator

GPRSChargingGateway


Authentication ServerAuthentication Server

Authentication server acts as the main control point for the WLAN management A single authentication server can support multiple access

controller

Authentication server hides the cellular infrastructure from the WLAN access network

A predefine bit pattern in the HLR subscriber service profile indicate the WLAN subscription


Access ControllerAccess Controller

The access controller provides an Internet gateway between the WLAN network and the fixed IP core

Access controller will be the DHCP termination point

Access controller is in charge of gathering information for billing


C/WLAN Control PlaneC/WLAN Control PlaneC/WLAN Control PlaneC/WLAN Control Plane

802.11802.11

IPIP

UDPUDPTCPTCP

WLANWLANXAPXAP

Mobile TerminalMobile Terminal

802.11802.11 802.3802.3

IPIP

802.3802.3 WANWAN

TCPTCPUDPUDP

IPIP

WLANWLANXAPXAP

RADIUSRADIUS

WANWAN 802.3802.3

TCPTCPUDPUDP

IPIP

Access PointAccess Point Access Controller

Through ControllerManager

RADIUSRADIUS

802.3802.3

UDPUDP

IPIP

GTPGTP

GTPGTPThrough

AccountingManager

SIM Authentication

CDR Transmission


GPRSChargingGateway


Accounting and BillingAccounting and Billing

The authentication server converts the accounting data to standard GPRS charging data record (CDR)

The authentication server verifies the received accounting data related to an IMSI

The authentication server delivers the generated CDRs to the charging gateway


Simplified WLAN Network ModelSimplified WLAN Network Model

UE

Intranet / Internet

WLANAccess Network

(with or without an intermediate

network)

AAAServer

Diameteror Radius Server

Includes Computer, WLAN card,etc.

Includes WLAN access points and may include routers, or intermediate AAA elements


WLAN Radio Technologies (1)WLAN Radio Technologies (1)

Attribute 802.11b Bluetooth 802.11a HiperLan/2

Frequency 2.4 GHz 2.4 GHz 5 GHz 5 GHz

Physical Layer Direct SequenceSpread Spectrum

(DSSS)

FrequencyHopping Spread

Spectrum

(FHSS)

OrthogonalFrequency

DivisionMultiplexing

(OFDM)

OFDM

Channel Width 22 MHz 1MHz 22 MHz 22 MHz

Range 150 ft (indoors)

300 ft (outdoors)

30 ft (with 1mW) 100 ft (indoors)

200 ft(outdoors)

Expected to besame as 802.11a

DataThroughputs

1,2,6,11 Mbps 720 Kbps 6,9,12,18,36,54Mbps (speed

varies asdistance fromAccess Point)

Same as 802.11a


WLAN Radio Technologies (2)WLAN Radio Technologies (2)

Attribute 802.11b Bluetooth 802.11a HiperLan/2

MAC CSMA/CA inDistributed

CoordinatedFunction Mode

(DCF)

(optional) PollingBased in PointCoordination

Function (PCF)

Time DivisionDuplex (TDD) with

a Master/SlavePolling Mechanism

Same as 802.11b TDMA with TDD

Miscellaneous High Speed DataApplications

Susceptible tointerference from

Bluetooth andother devices

Wire Replacement;

Inexpensive

Low componentcount

Low Power

Improve SpectralEfficiency over

802.11b

Products notavailable yet


High Level Requirements and PrinciplesHigh Level Requirements and Principles

• There is a set of high level functional requirements that have to be met when inter-working between WLAN and 3GPP is to be carried out.

• The specifications classify these requirements in:

Access Control Principles and Requirements Authentication Methods User Identity Charging Requirements and Principles Network Selection Principles


Access Control Requirements (1)Access Control Requirements (1)• The specifications require that all legacy WLAN terminals be supported

However software upgrades may be required for e.g. security reasons.• There must be minimal impact on

the user equipment (UE) (i.e. client software) existing WLAN networks the HSS/HLR/AuC

• The need for operators to administer and maintain end user software shall be minimised

• Existing SIM and Universal SIM (USIM) shall be supported R6 USIM may include new functionality if seemed necessary e.g. in order to

improve privacy.


Access Control Requirements (2)Access Control Requirements (2)• The WLAN connection established for a 3GPP subscriber shall have no impact

to the capabilities of having simultaneous Packet Switched (PS) and Circuit Switched (CS) connections for the same subscriber

• Methods for key distribution to the WLAN access network shall be supported

• Authorisation shall occur upon the success of the authentication procedure

• The authorisation mechanism shall be able to inform the user and WLAN immediately of any change in service provision.


Access Control Requirements (3)Access Control Requirements (3)• Policy control applies to the services authorised for the user (I.e.: voice, data,

SMS, etc.)

• It shall be possible to indicate to the user any conditions for use of an authorised service

• Results of authorisation requests shall be indicated to the WLAN, so that the WLAN can take appropriate action


Access Control Principles (1)Access Control Principles (1)• End to End Authentication

It is to be executed between WLAN UE and 3GPP AAA Server

It has to be independent on the WLAN technology utilised within WLAN Access network and shall be based on Extensible Authentication Protocol (EAP)

• Transporting Authentication Signalling over WLAN Radio Interface It is carried between WLAN UE and WLAN Access Network by WLAN Access

Technology specific protocols

For IEEE 802.11 type of WLAN radio interfaces the WLAN radio interface shall conform to IEEE 802.11i standard,

ETSI HIPERLAN2 shall be conform with TS 101 761, 101 493 , Draft TS [H2-3G interworking].


Access Control Principles (2)Access Control Principles (2)• Transporting Authentication Signalling between WLAN and 3GPP network

The transport of Authentication signalling between WLAN and 3GPP network shall be based on standard Diameter or RADIUS (Remote Authentication Dial In User Service) protocols.

• Service Selection The end to end signalling shall include means for delivering encrypted service

selection information from the UE to the 3GPP AAA server. The service selection information may contain APN(???) and External Protocol

Configuration Options as they are defined in 3GPP TS 24.008. Before admitting the user to access WLAN, 3GPP AAA server shall verify users

subscription to the indicated APN against the WLAN subscriber profile retrieved from HSS


Authentication MethodsAuthentication Methods• The following is a list of a certain number of proposals with regards to

authentication methods for WLAN and 3GPP inter-working.

Universal SIM (USIM) based Authentication

– The USIM does not need to be included in the WLAN card. The WLAN device can be linked with a UE supporting a USIM via, for example Bluetooth, Irda, USB or serial cable.

GSM SIM based Authentication

– Useful for GSM subscribers that do not have a UICC(??) card with a USIM application.

WLAN specific SIM and USIM functions

– For these SIMs and pre-release 6 USIMs the temporary ID shall be stored in the WLAN UE (outside the SIM/USIM).

Re-authentication


User Identity (1)User Identity (1)• The network authentication procedure uses the EAP method, where the User

Identity field carries the user identity composed by the Public User Identity and a Home Network Domain Name

• The home network domain name shall be in the form of an Internet domain name

• The UE shall derive the home network domain name from the IMSI as described in the following steps:

1. Take the first 5 or 6 digits, depending on whether a 2 or 3 digit MNC is used and separate them into MCC and MNC with "."; and

2. Reverse the order of the MCC and MNC. Append to the result: "WLAN.3gppnetwork.org"


User Identity (2)User Identity (2)• EXAMPLE: If the IMSI in use is 234150999999999;

Then MCC: 234; MNC: 15; MSIN: 0999999999; and

The home domain name is 15.234.WLAN.3gppnetwork.org.• For user identity protection a Temporary Identity can be used.

A temporary identifier is necessary to replace the IMSI in radio transmissions as it protects the user against tracing from unauthorised access networks.

• The current version of the specifications considers that temporary identifiers are allocated and stored in the 3GPP AAA Server.


Charging RequirementsCharging Requirements• With regards to the charging requirements, this is what is expected:

The W-LAN access network will report the W-LAN access usage to the appropriate 3GPP system

The 3GPP system will command some operations on a specific ongoing W-LAN access session

– This can be useful in the context of prepaid processing.

An operator will be able to maintain a single prepaid account for W-LAN, PS, CS, and IMS per user

The 3GPP system will be in charge of processing the W-LAN access resource usage information into 3GPP compatible format (CDR)


Charging PrinciplesCharging Principles• Offline Charging

WLAN offline charging includes mechanisms for collection and forwarding information about occurred WLAN access resource usage.

• Online Charging

Online charging includes mechanism to get online permission from an online charging system to allow an online charged subscriber to access WLAN.


Network Selection Principles (1)Network Selection Principles (1)• If the WLAN radio technology allows for features enabling radio access network

sharing or provider selection these shall be reused for network selection in 3GPP-WLAN interworking.

• There are three particular cases to study:

IEEE 8002.11 WLANs

HiperLAN1/ WLANs

Bluetooth WLANs

• Only the first one has been covered by the specifications, so far


Network Selection Principles - IEEE 802.11Network Selection Principles - IEEE 802.11

• The WLAN network name is provided in WLAN beacon signal in the so called SSID (Service Set ID) information element.

• Alternatively, a UE can actively solicit support for specific SSIDs by sending a probe request message and receive a reply if the access point does support the solicited SSID

• Once confirmed the availability of one of the preferred SSIDs either in beacon or in a probe response message, WLAN UE performs association with the particular access point using the selected preferred SSID.


Network Selection Principles - IEEE 802.11Network Selection Principles - IEEE 802.11

• WLAN acting in 3GPP reference model as a DIAMETER client for transport of authentication exchanges carried in EAP, shall use the used SSID as information that determines the first hop routing of DIAMETER frames, according to 3GPP reference model this implies selection of 3GPP AAA proxy.

• In this way the user can select either his/her home operator or its preferred roaming partner’s 3GPP AAA proxy.

• 3GPP AAA Proxy then makes further AAA routing decision based on the NAI it has received.


Reference ModelReference Model• The specifications covers two cases:

• 1) Non Roaming WLAN Inter-working Reference Model

This term is used in the specifications to refer to roaming between 3GPP networks. That is, this applies to the case when a WLAN user is attached to a 3GPP system but it does not (or cannot??) roam to another WLAN in another 3GPP system.

• 2) Roaming WLAN Inter-working Reference Model


Non Roaming Reference ModelNon Roaming Reference Model

UE

Intranet / Internet

WLANAccess Network


network)

3GPPAAA

PacketData GW

OCS

HSS HLR CGw/CCF

Wr/Wb

Wn

Wi

Wo

Wx Wf

D’/Gr’

3GPP Home Network


Roaming WLAN Inter-working Reference ModelRoaming WLAN Inter-working Reference Model

UE

Intranet / Internet

WLANAccess Network


network)

PacketData GW

OCS

HSS

HLR

CGw/CCF

Wn

Wi

Wo

Wx

Wf

D’/Gr’

3GPP Home Network

3GPPAAA

Border GW (opt)

Packet Data GW

CGw/CCF

Wr/Wb

Wr/Wb Wf

3GPP Visited Network

3GPPAAA Proxy

Wn

Wi


Roaming WLAN Inter-working Reference Model - NotesRoaming WLAN Inter-working Reference Model - Notes

• The Home Network is responsible for access control• Charging records can be generated in the visited and/or the home 3GPP

networks.• The Wx and Wo interfaces are intra-operator• The 3GPP network interfaces to other 3GPP networks, WLANs, and

intermediate networks via the Wr and Wb interfaces• The 3GPP proxy AAA relays access control signalling and accounting

information to the home 3GPP AAA server It can also issue charging records to the visited network CGw/CCF when

required


Network ElementsNetwork Elements

• The network elements of the 3GPP-WLAN inter-working reference model are:

The User Equipment (UE) The 3GPP AAA server The 3GPP Proxy AAA server The HLR/HSS The Border Gateway

– Optional

The Packet Data Gateway


User Equipment (UE)User Equipment (UE)

• When equipped with (U)ICC?? card including (U)SIM it is utilised by a 3GPP subscriber to access the WLAN inter-working service

• It may be capable of WLAN access only, or it may be capable of both WLAN and 3GPP System access Some UE may be capable of simultaneous access to both WLAN and 3GPP

systems• The UE may include terminal types whose configuration (e.g. interface to a

(U)ICC), operation and software environment are not under the exclusive control of the 3GPP system operator, such as a laptop computer or PDA with a WLAN card, (U)ICC card reader and suitable software applications.


3GPP AAA Server 3GPP AAA Server

• The 3GPP AAA server is located within the 3GPP network.

• The 3GPP AAA server :

Retrieves authentication information and subscriber profile (including subscriber's authorisation information) from the HLR/HSS of the 3GPP subscriber's home 3GPP network;

Authenticates the 3GPP subscriber based on the authentication information retrieved from HLR/HSS.

– The authentication signalling may pass through AAA proxies.

Communicates authorisation information to the WLAN potentially via AAA proxies.

Registers its (the 3GPP AAA server) address or name with the HLR/HSS for each authenticated and authorised 3GPP subscriber.

May act also as a AAA proxy (see next slide).


3GPP Proxy AAA Server (1)3GPP Proxy AAA Server (1)

• The 3GPP proxy AAA functionality can reside in a separate physical network node

• It may reside in the 3GPP AAA server or any other physical network node

• It represents a Diameter proxying and filtering function that resides in the visited 3GPP network.

WLANAccess Network


network)

3GPPAAA

Wr/Wb 3GPPAAA Proxy

Wr/Wb


3GPP

Home Network


3GPP Proxy AAA Server (2)3GPP Proxy AAA Server (2)

• The 3GPP proxy AAA functions include:

Relaying the AAA information between WLAN and the 3GPP AAA Server

Enforcing policies derived from roaming agreements between 3GPP operators and between WLAN operator and 3GPP operator

Reporting charging/accounting information to local Charging Collection Function(CCF)/Charging Gateway (CGw) for roaming users

Service termination (O&M initiated termination from visited NW operator)

Receiving authorisation information (Subscriber information)

Forwarding authorisation information to WLAN

Rejection of authorisation according to local policy


HLR/HSS HLR/HSS

• The HLR/HSS located within the 3GPP subscriber's home network is the entity containing authentication and subscription data required for the 3GPP subscriber to access the WLAN inter-working service

HLR


Packet Data Gateway (1)Packet Data Gateway (1)

• The Packet Data Gateway is a node via which packet data networks are connected to 3GPP inter-working WLAN.

WLANAccess Network


network)Packet Data

Gateway

Wn Border

Gateway


3GPP Home Network Wi

WLANAccess Network


network)

Wn Border

Gateway

3GPP Home NetworkPacket Data

Gateway

Wi


Packet Data Gateway (2)Packet Data Gateway (2)

• The location of Packet Data Gateway may be different for each specific service accessed WLAN.

For some WLAN connections no Packet Data Gateway is used,

For some accessed services the Packet Data Gateway may be in the home network and

For some accessed services it may locate in the visited Network


Border Gateway Border Gateway

• The Border Gateway is an optional gateway via which the data between WLAN and Packet Data Gateway can be routed

WLANAccess Network


network)

Border GW (opt)

Packet Data GW

Wn

Wi


Reference Points (Interfaces)Reference Points (Interfaces)

• The interfaces between the network elements are referred to in the specifications as reference points. They are:

Wr: Connects WLAN AN to the 3GGP AAA server

Wx: Located between the 3GPP AAA server and the HSS

D’/Gr’: Located between the 3GPP AAA server and the HLR

Wb: Located between the WLAN AN and the 3GPP network

Wo: Used by a 3GPP server to communicate with the OCS

Wf: Located between the 3GPP AAA server and the CCF/CGw

Wn: Tunnels WLAN user data towards the 3GPP system

Wi: Connects the PDGW and a Packet Data Network


WrWr

• The reference point Wr connects the WLAN access network, possibly via intermediate networks, to the 3GPP AAA Server.

• The prime purpose of the protocols crossing this reference point is to transport authentication, authorisation and related information in a secure manner.

• This reference point has to accommodate also legacy WLAN access networks and thus is DIAMETER or RADIUS-based.

WLANAccess Network


network)

Wr3GPP

AAA Proxy


3GPPAAA

3GPP

Home NetworkWr


Wr FunctionalityWr Functionality

• The functionality of the Wr reference point (interface) is to transport RADIUS/DIAMETER frames:

Carrying data for authentication signalling between a WLAN UE and a 3GPP AAA Server

Carrying data for authorisation signalling between a WLAN AN and a 3GPP AAA server

Carrying keying data for the purpose of radio interface integrity protection and encryption

Used for purging a user from the WLAN access for immediate service termination


WxWx

• This reference point is located between 3GPP AAA Server and HSS ??.

• The prime purpose of the protocol(s) crossing this reference point is communication between WLAN AAA infrastructure and HSS.

• The protocol crossing this reference point is either MAP or DIAMETER-based.

3GPP Home Network

HSS

Wx

3GPP AAA


Wx FunctionalityWx Functionality

• The functionality of the reference point is to enable:

Retrieval of authentication vectors, e.g. for USIM authentication, from HSS.

Retrieval of WLAN access-related subscriber information (profile) from HSS

Registration of the 3GPP AAA Server of an authorised WLAN user in the HSS.

Indication of change of subscriber profile within HSS (e.g indication for the purpose of service termination).


3GPP Home Network

D’/Gr’D’/Gr’

• It is located between the 3GPP AAA Server and HLR

• The prime purpose of the protocol(s) crossing this reference point is communication between WLAN AAA infrastructure and HLR and is(are) MAP-based.

• The functionality of the reference point is to enable retrieval of authentication vectors, e.g. for USIM authentication, from HLR.

• D'/Gr' include a subset of D/Gr Reference Point.

D’/Gr’ HLR3GPP AAA


WbWb

• It is located between WLAN AN and 3GPP network

• The prime purpose of the protocols crossing this reference point is to transport charging-related information in a secure manner

• Wb has to accommodate also legacy WLAN AN and thus should be DIAMETER or RADIUS-based

WLANAccess Network


network)

WbWb


3GPP

Home Network3GPP AAA

Proxy 3GPP AAA


Wb FunctionalityWb Functionality

• The functionality of the reference point is to transport RADIUS/DIAMETER frames with charging signalling per each WLAN user

• The fact that a user is offline or online charged by his 3GPP subscription provider is transparent for the WLAN AN and thus for the Wb reference point

This will minimise the requirements put on the WLAN Access Network. It will also protect the confidentiality of the subscribers charging status

• However for online charged users the interval to deliver accounting information from WLAN AN over Wb reference point may typically be set to a smaller value than for offline charged users.


WoWo

• It is used by a 3GPP AAA server to communicate with 3GPP Online Charging System (OCS).

• The prime purpose of the protocol(s) crossing this reference point is to transport online charging related information so as to perform credit control for the prepaid subscriber.

• The protocol(s) crossing this interface shall be DIAMETER-based.

3GPP Home Network

OCS

Wo

3GPP AAA


WfWf

• This reference point is located between 3GPP AAA Server and 3GPP Charging Gateway Function (CGF)/Charging Collection Function (CCF).

• The prime purpose of the protocols crossing this reference point is to transport/forward charging information towards 3GPP operator’s Charging Gateway/Charging collection function.

3GPP Home Network

Wf

CGF/CCF3GPP AAA


Wf FunctionalityWf Functionality

• The information forwarded to Charging Gateway/Charging collection function is typically used for

generating bills for offline charged subscribers by the subscribers’ home operator

Calculation of inter-operator clearing charging from all roaming users. This inter operator clearing is used to settle the payments between visited and home network operator and/or between home/visited network and WLAN.

• The protocol(s) crossing this interface is (are) DIAMETER-based.

• The functionality of the reference point is to transport WLAN access-related charging data per each WLAN user


Wn (1)Wn (1)

• Wn indicates the reference point for transporting tunnelled WLAN user data towards a 3GPP system

• Routing of Wn reference point is service specific.

• For accessing home network services the Wn may be routed directly between WLAN and Home 3GPP Network

UE

WLANAccess Network


network)

PacketData GW

Wn

Wi

3GPP Home Network


Wn (2)Wn (2)

• For accessing home network services the Wn may be forced to go via Border Gateway functionality within the Visited Network

UE

WLANAccess Network


network)

Border GW

Wn


PacketData GW

Wi

3GPP Home Network

Wn


WiWi

• This is the reference point between Packet Data GW and a packet data network.

• The packet data network may be an operator external public or private packet data network or an intra operator packet data network, e.g. for provision of IMS services.

• Wi reference point is similar to the Gi reference point provided by the PS domain.

PacketData GW

Wi

3GPP Home Network


Authentication and AuthorisationAuthentication and Authorisation

UE WLAN 3GPP AAA

server HSS / HLR

1. WLAN Connection Setup

5. Diameter Access Accept

6. EAP / Success

2. EAP Request / Identity

3. EAP Response / Identity

[User ID in NAI format]

2. Necessary amount of EAP Request & EAPResponse message exchanges between UE and 3GPP AAA Server as specified in the utilised EAP type

.

3. Authentication info retrieval from HSS if info not yet available in 3GPP AAA server

4. Subscriber profile retrieval from HSS if info not yet available in this 3GPP AAA server.

retrieval from HSS if info not yet available in 3GPP AAA server

7. WLAN Registration to HSS if WLAN user not yet registered to this 3GPP AAA Server

[Keying material and authorisation information within Diameter message]


Subscriber Profile UpdateSubscriber Profile Update

3. Wx “Subscriber

Profile” procedure

HSS

1. User is registered to a 3GPP AAA

server

2. User subscription is modified in HSS

4. Authorisation information is updated to the

WLAN

UE WLAN 3GPP AAA Server


Cancelling WLAN Registration Cancelling WLAN Registration

UE WLAN old 3GPP

AAA server HSS

1. Users WLAN Subscription is

cancelled in HSS

4. Disconnection of the WLAN radio interface connection (if needed)

2. Wx "Cancel WLAN Registration"

3. Wr "Diameter Session Abort" procedure

(if needed)


Disconnecting a Subscriber by Online Charging SystemDisconnecting a Subscriber by Online Charging System

UE WLAN 3GPP AAA

server OCS

1. User is being online charged

4. Disconnection of the WLAN radio interface

connection

3. Wr "Diameter Session Abort" procedure

2. Online Credit Request denied by OCS


Charging offline charged subscribersCharging offline charged subscribers

4. 3GPP AAA Server sends charging data to CGw/CCF over Wf ref.

point

3. WLAN periodically sends collected charging

Information to 3GPPAAA Server over Wb

ref.point

1. WLAN User is Authenticated and Authorized

2. WLAN collects charging data

UE WLAN 3GPP AAA server

CGw/CCF


Charging online charged subscribersCharging online charged subscribers

UE WLAN 3GPP AAA

server OCS

5. 3GPP AAA Server requests credit from OCS over the Wo ref. point

4. WLAN periodically sends collected charging

information to 3GPP AAA Server over Wb

ref. point

1. WLAN User is Authenticated and user profile downloaded into 3GPP AAA server

3. WLAN collects charging data

2. 3GPP AAA server requests credit from OCS over Wo reference point

6. 3GPP AAA server periodically reports charging

information to CGw/CCF over Wf ref. point

CGw/CCF

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