Migration Toward 4G and All-IP Concept
WFI Confidential & ProprietaryPage 2
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
WFI Confidential & ProprietaryPage 3
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
WFI Confidential & ProprietaryPage 4
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
WFI Confidential & ProprietaryPage 5
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
WFI Confidential & ProprietaryPage 6
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
WFI Confidential & ProprietaryPage 7
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
WFI Confidential & ProprietaryPage 8
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
WFI Confidential & ProprietaryPage 9
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
WFI Confidential & ProprietaryPage 10
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
WFI Confidential & ProprietaryPage 11
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
WFI Confidential & ProprietaryPage 12
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
WFI Confidential & ProprietaryPage 13
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
WFI Confidential & ProprietaryPage 14
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
WFI Confidential & ProprietaryPage 15
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
WFI Confidential & ProprietaryPage 16
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.
WFI Confidential & ProprietaryPage 17
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
WFI Confidential & ProprietaryPage 18
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
WFI Confidential & ProprietaryPage 19
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)
WFI Confidential & ProprietaryPage 20
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
WFI Confidential & ProprietaryPage 21
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)
WFI Confidential & ProprietaryPage 22
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
WFI Confidential & ProprietaryPage 23
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
WFI Confidential & ProprietaryPage 24
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
WFI Confidential & ProprietaryPage 25
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
WFI Confidential & ProprietaryPage 26
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
WFI Confidential & ProprietaryPage 27
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
WFI Confidential & ProprietaryPage 28
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.
WFI Confidential & ProprietaryPage 29
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
WFI Confidential & ProprietaryPage 30
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
WFI Confidential & ProprietaryPage 31
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
WFI Confidential & ProprietaryPage 32
• 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
WFI Confidential & ProprietaryPage 33
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
WFI Confidential & ProprietaryPage 34
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
WFI Confidential & ProprietaryPage 35
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
WFI Confidential & ProprietaryPage 36
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
WFI Confidential & ProprietaryPage 37
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)
WFI Confidential & ProprietaryPage 38
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
WFI Confidential & ProprietaryPage 39
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
WFI Confidential & ProprietaryPage 40
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
WFI Confidential & ProprietaryPage 41
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
WFI Confidential & ProprietaryPage 42
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
WFI Confidential & ProprietaryPage 43
Functional PDP State ModelFunctional PDP State Model
INACTIVE
ACTIVE
Activate PDPContext
Deactivate PDP Contextor
MM state change to IDLEor PMM-DETACHED
WFI Confidential & ProprietaryPage 44
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
WFI Confidential & ProprietaryPage 45
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.
WFI Confidential & ProprietaryPage 46
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
WFI Confidential & ProprietaryPage 47
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
WFI Confidential & ProprietaryPage 48
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
WFI Confidential & ProprietaryPage 49
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
WFI Confidential & ProprietaryPage 50
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)
WFI Confidential & ProprietaryPage 51
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
WFI Confidential & ProprietaryPage 52
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
WFI Confidential & ProprietaryPage 53
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
WFI Confidential & ProprietaryPage 54
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
WFI Confidential & ProprietaryPage 55
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)
WFI Confidential & ProprietaryPage 56
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
WFI Confidential & ProprietaryPage 57
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).
WFI Confidential & ProprietaryPage 58
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
WFI Confidential & ProprietaryPage 59
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
WFI Confidential & ProprietaryPage 60
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
WFI Confidential & ProprietaryPage 61
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
WFI Confidential & ProprietaryPage 62
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
WFI Confidential & ProprietaryPage 63
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
WFI Confidential & ProprietaryPage 64
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
WFI Confidential & ProprietaryPage 65
Coding Schemes and Coverage ImpactCoding Schemes and Coverage Impact
A Review of UMTSA Review of UMTS
WFI Confidential & ProprietaryPage 67
“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
WFI Confidential & ProprietaryPage 68
Global
Suburban
Macro-Cell
Urban
Micro-Cell In- Building
Pico-Cell
Home-Cell
UMTS Vision
WFI Confidential & ProprietaryPage 69
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
WFI Confidential & ProprietaryPage 70
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
granularity 40kbit/s
BER 10-3 (20 ms)BER 10-7 (300 ms)
512 kbit/s BER = 10-5 to 10-8
Max Transfer Delay150 ms or more
Indoor/ Low rangeoutdoor(Terminal speed up to10 km/ h)
2 Mbit/s
granularity 200kbit/s
delay 20 - 300 msBER 10-3 (20 ms)BER 10-7 (300 ms)
2 Mbit/s BER = 10-5 to 10-8
Max Transfer Delay150 ms or more
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
WFI Confidential & ProprietaryPage 71
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)
WFI Confidential & ProprietaryPage 72
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
WFI Confidential & ProprietaryPage 73
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
WFI Confidential & ProprietaryPage 74
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)
WFI Confidential & ProprietaryPage 75
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
WFI Confidential & ProprietaryPage 76
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
WFI Confidential & ProprietaryPage 77
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
WFI Confidential & ProprietaryPage 78
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
WFI Confidential & ProprietaryPage 79
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)
WFI Confidential & ProprietaryPage 80
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).
WFI Confidential & ProprietaryPage 81
Transport ChannelsTransport Channels
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)
WFI Confidential & ProprietaryPage 82
Transport ChannelsTransport Channels
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.
WFI Confidential & ProprietaryPage 83
Transport ChannelsTransport Channels
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.
WFI Confidential & ProprietaryPage 84
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)
WFI Confidential & ProprietaryPage 85
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)
WFI Confidential & ProprietaryPage 86
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
WFI Confidential & ProprietaryPage 87
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
WFI Confidential & ProprietaryPage 88
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)
WFI Confidential & ProprietaryPage 89
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
WFI Confidential & ProprietaryPage 90
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.
WFI Confidential & ProprietaryPage 91
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
WFI Confidential & ProprietaryPage 92
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
WFI Confidential & ProprietaryPage 93
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
WFI Confidential & ProprietaryPage 94
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
WFI Confidential & ProprietaryPage 95
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
WFI Confidential & ProprietaryPage 96
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
WFI Confidential & ProprietaryPage 97
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
WFI Confidential & ProprietaryPage 98
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
WFI Confidential & ProprietaryPage 100
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?
WFI Confidential & ProprietaryPage 101
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
WFI Confidential & ProprietaryPage 102
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
WFI Confidential & ProprietaryPage 103
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
WFI Confidential & ProprietaryPage 104
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
WFI Confidential & ProprietaryPage 105
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
WFI Confidential & ProprietaryPage 106
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
WFI Confidential & ProprietaryPage 107
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
WFI Confidential & ProprietaryPage 108
Authentication ProcedureAuthentication Procedure
Operator Core IP
Mobility Router/Switch
Public WLAN
GPRS RAN
CellularCore
GGSN
SS7
MSC/HLR
AuthenticationServer
(Access Controller)SIM
1) Terminal authentication through WLAN (SIM)
2) SIM authentication and user accounting through IP
3) GSM authentication andcharging messaging
SGSN
WFI Confidential & ProprietaryPage 109
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
WFI Confidential & ProprietaryPage 110
WLAN Elements in WLAN Elements in Cellular Systems SystemsWLAN Elements in WLAN Elements in Cellular Systems Systems
Mobility Router/Switch
(Access Controller)
AuthenticationServer
RADIUS
MAP
MSC HLR
Access Operator Cellular Operator
GPRSChargingGateway
WFI Confidential & ProprietaryPage 111
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
WFI Confidential & ProprietaryPage 112
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
WFI Confidential & ProprietaryPage 113
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
AuthenticationServer
GPRSChargingGateway
WFI Confidential & ProprietaryPage 114
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
WFI Confidential & ProprietaryPage 115
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
WFI Confidential & ProprietaryPage 116
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
WFI Confidential & ProprietaryPage 117
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
WFI Confidential & ProprietaryPage 118
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
WFI Confidential & ProprietaryPage 119
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.
WFI Confidential & ProprietaryPage 120
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.
WFI Confidential & ProprietaryPage 121
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
WFI Confidential & ProprietaryPage 122
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].
WFI Confidential & ProprietaryPage 123
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
WFI Confidential & ProprietaryPage 124
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
WFI Confidential & ProprietaryPage 125
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"
WFI Confidential & ProprietaryPage 126
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.
WFI Confidential & ProprietaryPage 127
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)
WFI Confidential & ProprietaryPage 128
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.
WFI Confidential & ProprietaryPage 129
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
WFI Confidential & ProprietaryPage 130
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.
WFI Confidential & ProprietaryPage 131
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.
WFI Confidential & ProprietaryPage 132
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
WFI Confidential & ProprietaryPage 133
Non Roaming Reference ModelNon Roaming Reference Model
UE
Intranet / Internet
WLANAccess Network
(with or without an intermediate
network)
3GPPAAA
PacketData GW
OCS
HSS HLR CGw/CCF
Wr/Wb
Wn
Wi
Wo
Wx Wf
D’/Gr’
3GPP Home Network
WFI Confidential & ProprietaryPage 134
Roaming WLAN Inter-working Reference ModelRoaming WLAN Inter-working Reference Model
UE
Intranet / Internet
WLANAccess Network
(with or without an intermediate
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
WFI Confidential & ProprietaryPage 135
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
WFI Confidential & ProprietaryPage 136
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
WFI Confidential & ProprietaryPage 137
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.
WFI Confidential & ProprietaryPage 138
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).
WFI Confidential & ProprietaryPage 139
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
(with or without an intermediate
network)
3GPPAAA
Wr/Wb 3GPPAAA Proxy
Wr/Wb
3GPP Visited Network
3GPP
Home Network
WFI Confidential & ProprietaryPage 140
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
WFI Confidential & ProprietaryPage 141
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
WFI Confidential & ProprietaryPage 142
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
(with or without an intermediate
network)Packet Data
Gateway
Wn Border
Gateway
3GPP Visited Network
3GPP Home Network Wi
WLANAccess Network
(with or without an intermediate
network)
Wn Border
Gateway
3GPP Home NetworkPacket Data
Gateway
Wi
WFI Confidential & ProprietaryPage 143
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
WFI Confidential & ProprietaryPage 144
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
(with or without an intermediate
network)
Border GW (opt)
Packet Data GW
Wn
Wi
WFI Confidential & ProprietaryPage 145
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
WFI Confidential & ProprietaryPage 146
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
(with or without an intermediate
network)
Wr3GPP
AAA Proxy
3GPP Visited Network
3GPPAAA
3GPP
Home NetworkWr
WFI Confidential & ProprietaryPage 147
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
WFI Confidential & ProprietaryPage 148
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
WFI Confidential & ProprietaryPage 149
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).
WFI Confidential & ProprietaryPage 150
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
WFI Confidential & ProprietaryPage 151
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
(with or without an intermediate
network)
WbWb
3GPP Visited Network
3GPP
Home Network3GPP AAA
Proxy 3GPP AAA
WFI Confidential & ProprietaryPage 152
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.
WFI Confidential & ProprietaryPage 153
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
WFI Confidential & ProprietaryPage 154
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
WFI Confidential & ProprietaryPage 155
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
WFI Confidential & ProprietaryPage 156
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
(with or without an intermediate
network)
PacketData GW
Wn
Wi
3GPP Home Network
WFI Confidential & ProprietaryPage 157
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
(with or without an intermediate
network)
Border GW
Wn
3GPP Visited Network
PacketData GW
Wi
3GPP Home Network
Wn
WFI Confidential & ProprietaryPage 158
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
WFI Confidential & ProprietaryPage 159
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]
WFI Confidential & ProprietaryPage 160
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
WFI Confidential & ProprietaryPage 161
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)
WFI Confidential & ProprietaryPage 162
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
WFI Confidential & ProprietaryPage 163
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
WFI Confidential & ProprietaryPage 164
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
Top Related