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UMTS System OverviewUMTS System Overviewyy
Phone LinMobile Communications Networking (MCN)Mobile Communications Networking (MCN)
LAB,Dept. of Computer Science & Information
Engineering,National Taiwan University
E il li @ i t d t1
Email: [email protected]
ReferenceReference
The Most Materials of this talk is summarized by ythe UMTS System Overview course held by the “Informa Telecoms Ltd”Informa Telecoms Ltd .
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OutlinesOutlines
Part 1: UMTS Services and Applications pp
Part 2: UMTS Architecture
Part 3: WCDMA in UMTS
Part 4: Mobility Management Procedure in UMTSUMTS
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Part 1: UMTS Services and A li ti Applications
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OutlinesOutlines
Fundamental UMTS Service Conceptsp
Example Services
Quality of Service
The Virtual Home Environment
Security
User EquipmentUser Equipment
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F d t l UMTS S i C tFundamental UMTS Service Concepts
Fundamental UMTS Service Concept 1: Service Support Requirements
Fundamental UMTS Service Concept 2:Fundamental UMTS Service Concept 2:Interactive vs. Distribution Services
F d t l UMTS S i C t 3Fundamental UMTS Service Concept 3:Service Differentiation
Fundamental UMTS Service Concept 4:Telecommunications Service Typesyp
Fundamental UMTS Service Concept 5:The Service Architecture Concept
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The Service Architecture Concept
Concept 1: Service Support Concept 1: Service Support Requirements (1/3)
The continued evolution of GSM toward UMTSKey GSM Phase 2+ features carry straight into UMTS
Hi h d t t ( t 2 Mb )High data rates (up to 2 Mbps)
Open Service Creation
Flexible Multimedia Service Support
QoS GuaranteeQoS Guarantee
Roaming with All Services
Effi i t I t ki ith th I t tEfficient Interworking with the Internet
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Concept 1: Service Support Requirements (2/3)
From narrowband (e.g., speech) to wideband ( g , p )(up to 2Mbps)
Th i it it h d i i ti li it d 64kb/The circuit-switched services are in practice limited 64kb/s in UMTS This is the capability of the MSC switching
Service Creation by Third party developers or service providers.p
UMTS is designed to offer a “Toolkit of Functionality”, i.e., guidelines and service capability definitions which g p yapplication developers can follows.
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Concept 1: Service Support p ppRequirements (3/3)
Support for services made up of different media pp psources, capable of being delivered as the same timetime.
Multimedia
Definitions and Guarantees on Service quality.
Seamless roaming with UMTS applications and services.
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Concepts 2: Interactive vs. Concepts 2: Interactive vs. Distribution Services
Interactive Services:Two wayConversationalMessagingRetrieval
Distribution Services:Without user control: Broadcasting ServicesWith user control: access to the sequence numbering allows users to control of the start or order
Cell Broadcasting is defined as a requirement inCell Broadcasting is defined as a requirement in Release ’99 to guarantee continuity
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Concepts 3: Service Differentiation Concepts 3: Service Differentiation (1/3)
Standardized Services (Defined “end-to-end”)( )These are implemented in UMTS using standardized interfaces to ensure interoperability.interfaces to ensure interoperability.
They are available to all operators.
E l S h i t l i b iExample: Speech services, tele-services, bearer services, and supplementary services.
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Concepts 3: Service Differentiation p(2/3)
Operator specific servicesp pNot standardized, and thus offer differentiation between operators.operators.
They can be implemented at UMTS entities or by using toolkits, such as CAMEL, SAT MExE.toolkits, such as CAMEL, SAT MExE.
Implementation of these services on different platform is completely vendor specific.completely vendor specific.
Developers can be sure that the same application will work in other networks supporting such toolkits.in other networks supporting such toolkits.
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Concepts 3: Service Differentiation p(3/3)
Applications:ppThese are not standardized, but can be implemented by using standardized programming interfaces (APIs) to theusing standardized programming interfaces (APIs) to the service capability.
Service Capability Features: which describes theService Capability Features: which describes the functionalities of the service capabilities.
(1) They can be used by developers as guidelines to build(1) They can be used by developers as guidelines to build applications.
(2) Within the end-user terminal, service capabilities are(2) Within the end user terminal, service capabilities are again accessed via APIs.
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Concepts 4: Telecommunications Service Concepts 4: Telecommunications Service Types
Two types of basic telecommunications ypservices:
B i S i B S i Additi l S iBasic Services: Bearer Service Additional Services: Bearer Services & Supplementary Service
B i S i T l i Additi l S iBasic Services: Teleservices Additional Services: Teleservices & Supplementary Service
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Bearer Services: An Important Element in Bearer Services: An Important Element in the New QoS Control Capabilities of UMTS
Bearer services are defined as basic transport “Pipes” with specified capabilities.
For a user-requested service to be delivered,q ,The network will assign the most relevant bearer services needed to carry that service type.
Assignment and release of bearers is provided by a bearer control function.
Bearers are independent of radio environment fixed with transmission systems (i e theradio environment, fixed with transmission systems (i.e., the underlying transport).
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B S iBearer Services
Bearer services can be considered as layers.y
The overall UMTS bearer service required to enable an end to end service must in turnenable an end-to-end service must in turn depend on lower level bearer services:
For example, Radio Access Bearer and Core Network Bearer
Fall into two categories: (1) Circuit Switched Bearer Services; (2) Packet Switched Bearer ; ( )Services.
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TeleservicesTeleservices
Teleservices are defined end-to-end.Include definition of the terminal equipment function.
(1) Speech (Adaptive Multirate; AMR); (2) Voice Group Services; (3) Internet Access; (4) p ; ( ) ; ( )Emergency Call; (5) Fax; (6) SMS
Voice Group Services: Voice Group Call & Voice Broadcast
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Supplementary Services (1/2)Supplementary Services (1/2)
Call Filteringg
Number Identification (Calling Line ID Functions)Functions)
Call Offering (Call Forwarding Functions)Call Offering (Call Forwarding Functions)
Call Completion (Call Waiting, Call Hold)
Multi Party Service
Community Of Internet (Closed User Groups)
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Supplementary Services (2/2)Supplementary Services (2/2)
User to User Signalingg g
Charging Advice & Information
Call Restriction (Call Barring Functions)
Call TransferCall Transfer
Call Completion when Busy
Name Identification
M lti llMulticall
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Concepts 5: Service Architecture Concepts 5: Service Architecture Concept
Bearer Control = In order to assign the most appropriate g pp presources in transport of the application data
Call Control = to set up manage and release circuitCall Control = to set-up, manage and release circuit-switched call connections
Session Management = to manage packet-switched data transport
Mobility Management = to track a user’s movement and ensure data delivery to the current locationensure data delivery to the current location
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Example ServicesExample Services
Multimedia Services – Circuit-Switched Domain
Multimedia Services – Packet-Switched Domain
The Multimedia Messaging Service
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Multimedia Services: Circuit-Multimedia Services: CircuitSwitched Domain
Is one where two or more media components are combined within one call, for example,
Speech + Video + Graphic Data
CS multimedia in UMTS is based on H324
The following bit rate options are defined in UMTS toThe following bit-rate options are defined in UMTS to ease inter-working of 3G-324M Calls
64 56 33 6 32 and 28 8 kb/s for mobile to mobile64, 56, 33.6, 32 and 28.8 kb/s for mobile to mobile64 & 56 for mobile to/from N-ISDN33 6 and 28 8 for mobile to/from PSTN33.6 and 28.8 for mobile to/from PSTN32 for mobile to/from PHS call
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Multimedia Services: Packet-Multimedia Services: PacketSwitched Domain
Two solutions are discussed for PS MultimediaITU defined codec H.323
IETF t l SIP (S i I iti ti P t l)IETF protocol SIP (Session Initiation Protocol)
An initial invitation is used to locate all theAn initial invitation is used to locate all the user(s) to which a session is directed
E h “ ” b t l bil t i l ld llEach “user” may be actual mobile terminal, or could equally be a media source of some kind, for example, a PC-based applicationapplication
The users are identified by SIP URL’s.
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Multimedia Services: Multimedia Multimedia Services: Multimedia Messaging Service (MMS)
MMS is a non real-time service, in the same vein as SMS.
The messages can be stored before forwarded on to the recipient h th il bl d/ t t thwhenever they are available and/or request to see the messages.
MMS supports e-mail address or MSISDN address and WAP d l t l id i ifi t t fWAP development also provides significant support for MMS.
The user terminal operates the MMSE (Multimedia Messaging Service Environment).
MMSE provides delivery, storage and notification, which may be located in one network or distributed across networks.
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The Elements in MMSThe Elements in MMS
(1) The MMSE describes all the elements which provides the l t i tcomplete service to a user.
In the case of roaming, the visited network is included.
(2) Th MMS R l f iliti t f b t diff t i(2) The MMS Relay facilities transfer between different messaging systems, and can generate charging data, enabling the service to be billed.
(3) The MMS server is responsible for storage and handling of incoming and outgoing messages.
(4) The MMS user database contain subscription information.
(5) The MMS user agent resides on the user equipment or on a ( ) g q pdevice attached to this. It is an application layer function providing the users with the ability to view, compose and handle messages.
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Quality of ServicesQuality of Services
Important for packet-based servicesp p
Designed for efficient use of resources
Allow independent evolution of radio access and core networks
Support asymmetric services
f Q SEnable applications to define required QoS
-- Based upon assignement of appropriate UMTSBased upon assignement of appropriate UMTS bearer services.
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UMTS bearer service attributesUMTS bearer service attributes
QoS Class (Traffic Classes)QoS Class (Traffic Classes)
Maximum bit-rate
Guaranteed bit rateGuaranteed bit-rate
Delivery in-sequence
Size of data units
Error rates
Delivery erroneous data
Maximum transfer delayy
Traffic handling priority
Allocation/retention priority
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Allocation/retention priority
Conversational Class (delay Conversational Class (delay sensitive & real time)
Examples include speech, VoIP, video conferencing.
The characteristics required are controlled by human perception.
This class needs very low delay and to keep the time relation y y pbetween information entities.
Speech (4-25kps): Delay tolerance << 1s; Time Relation: Preserve; E T l 3% FERError Tolerance < 3% FER
Video (32-384kps): Delay tolerance << 1s; Time Relation: Preserve; Error Tolerance < 1% FERError Tolerance < 1% FER
Interactive games (<1k bps): Delay tolerance << 1s; Time Relation: -; Error Tolerance: No loss; Error Tolerance: No loss
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Streaming Class (Real Time)Streaming Class (Real Time)
For example, listening to real time video or audio.This class involves one way transport, live at the destination.There is the need to preserve the time relation between information by aligning at the receive end
Delay are possible, but can’t be too big.
Audio Streaming/Video Streaming: Delay Tolerance < g g y10s; Time Relation: Preserve; Error Tolerance: TolerantStill Image Paging: Delay Tolerance < 10s; Time g g g y ;Relation: Preserve; Error: intolerant
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Interactive ClassInteractive Class
This is for Internet-Type Applications, requiring yp pp q gresponsiveness.
At the message destination a response is expectedAt the message destination, a response is expected within a certain time, so round-trip delay needs to be minimizedminimized.
Voice Messaging: Delay Tolerance: < 1 s; Error tolerance: tolerant.
E-commerce WWW Browsing: Delay tolerance < 1 s;E commerce WWW Browsing: Delay tolerance 1 s; Error Tolerance: Intolerant
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Background ClassBackground Class
For applications which are entirely delay insensitive.pp y y
Information is only sent when resource is available.
Examples include file transfer, email delivery, SMS.
There is no expectation of when data will arrive DataThere is no expectation of when data will arrive. Data loss must be minor.
Fax: Delay Tolerance: > 10 s; Error tolerance: tolerant.
E-mail arrival notification: Delay Tolerance: > 10 s; ErrorE mail arrival notification: Delay Tolerance: 10 s; Error tolerance: intolerant.
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Th Vi t l H E i t (VHE)The Virtual Home Environment (VHE)
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Th Vi t l H E i t (VHE)The Virtual Home Environment (VHE)
It is defined as a concept for Personal Service pEnvironment (PSE) portability across network boundaries and between terminalsboundaries and between terminals.
PSE is defined in terms of one or more user profiles, which consists of two kinds of info:
Interface related Info (User Interface Profile Service look &Interface related Info (User Interface Profile – Service look & Feel)
Service Related Info (User Services ProfileService Related Info (User Services Profile –personalization etc.)
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Features of SIM ToolkitFeatures of SIM Toolkit
SIM belongs to the operatorEnables remote downloading of value added servicesSecureSecureEnables operator-specific services and handset customization:customization:
Control of MMIMenu ManagementMenu ManagementApplication ControlAccessory Managementy gCommunications & proactive commands
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CAMELCAMEL
CAMEL stands for “Customized Applications for ppMobile Network Enhanced Logic”.
Phase 1 Basic Call Related ActivityPhase 1 Basic Call-Related Activity
Phase 2 Includes Supplementary ServicesPhase 2 Includes Supplementary Services and User Interaction
Ph 3 I l d SMS GPRS HLR d tPhase 3 Includes SMS, GPRS, HLR data, network signaling Load
Phase 4 is part of 3GPP Release 4
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CAMELCAMEL
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Mobile Execution EnvironmentMobile Execution Environment
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Security ThreatsSecurity Threats
Masquerading (most common in 2G systems)q g ( y )
Eavesdropping (most common in 2G systems)
Subscription fraud (most common in 2G systems)systems)
Data manipulation
Service mis-use
Repudiation
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UMTS Security DomainsUMTS Security Domains
User Domain Securityy
Network Access Security
Network Domain Security
Application Domain Security
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User Domain SecurityUser Domain Security
Providing Secure Access to the mobile terminalg
The usage of USIM:The USIM contains user i.d. and an association with a home environment, and is based on Phase 2+ GSM SIM.
Emergency calls are allowed without USIM.
4 to 8 digit PIN4 to 8 digit PIN
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Network Access SecurityNetwork Access Security
Providing secure access to UMTS, in particular protecting the radio access link
The user is identified by a temporary ID given by the y p y g yvisited network.
Authentication of the user and confirmation that theAuthentication of the user and confirmation that the network is permitted to provide services happens each time a user sets up a connection.p
Confidentiality is provided by a cipher algorithm operating between terminal and the serving networkoperating between terminal and the serving network node.
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Network Domain SecurityNetwork Domain Security
Provides secure exchange of info between gnodes within the fixed part of the network, e.g., between the serving network and homebetween the serving network and home environment.
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Application domain securityApplication domain security
Enabling users and applications to securely g pp yexchange messages.
Application domain security involves secure messaging between the USIM and network, g g ,which requires authentication of the application and the origin of the data receivedand the origin of the data received.
These features are all based on the GSM SIM Application Toolkits security features.
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Mandatory User Equipment y q pRequirements (1/2)
Encrypted interface between terminal & UICC yp(UMTS IC Card)
Support GSM Ph2 & Ph2+ SIMSupport GSM Ph2 & Ph2+ SIM
Home & Serving NetworkHome & Serving Network registration/deregistration
L ti U d tLocation Update
Originate/receive a connection/connectionlessOriginate/receive a connection/connectionless service
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Mandatory User Equipment Mandatory User Equipment Requirements (2/2)
Terminal capability i.d. p yE.g., MExE class mark, and bearer service support
Emergency call support
E ti l ith tiEncryption algorithm execution
Ciphering indicatorCiphering indicator
Network Selection
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Elements of the UMTS IC CardElements of the UMTS IC Card
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Information Storage on UICCInformation Storage on UICC
UICC Card i.d.
Preferred language
Directory of applications
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Information Storage on USIMInformation Storage on USIM
USIM Service Table: Optional S i
Forbidden networks
Ph Id tifi ti
Capabilities Info
C fi ti I fServices Provided
IMSI (unique
Phase Identification
Ciphering key for GPRS
Configuration Info
Home Network search periodIMSI (unique
subscriber i.d. number)
GPRS
GPRS Location Information
search period
Broadcast channel info – used in cell
Language Indicator
Cell Broadcast Information
selection
Various security informationLocation
InformationEmergence call codes
Ph b
information
Cipher key
Access Control Classes
Phone numbers
Short messages and related info
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Classes and related info
P t 2 Th UMTS Part 2: The UMTS ArchitectureArchitecture
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OutlinesOutlines
UMTS Architecture – The Requirementq
The User Domain (USIM + ME Domains)
The Access Network
The Core NetworkThe Core Network
Other Network Elements
Release 4
N t k E l tiNetwork Evolution
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Aims of the UMTS ArchitectureAims of the UMTS Architecture
Flexibilityy
IMT2000 Interworking Modular Approach
Minimize SignalingApproach
Building onOptimize Transmission
Building on evolved GSMProtect existing Investments
Enable evolution
GSM
Enable evolution
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Some Key New Features of UMTS y(1/2)
Upgrades to existing GSM/GPRS elementsATM transportNew speech codecFlexibility in connection set-up, re-negotiation & clearingFlexibility in bearersSupport for VHEEnhanced charging & billing supportInterworking with other networks & numbering schemesTraffic flow measurements to enable management efficienciesgEnhanced IP mobility support
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UMTS Domains OverviewUMTS Domains Overview
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User DomainUser Domain
MS = ME domain + USIM domain
ME = MT (Radio) + TE (Applications)
The USIM domain and the ME domain are liked by the Cu interfaceby the Cu interface
The USIM Domain contains the data andThe USIM Domain contains the data and procedures allowing ME to securely identify itselfitself.
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Th T l t t d iThe Terms relevant to user domain
The subscriberIs associated with the home environment & responsible for payment
The userI th i d t i b th b ib ( dIs authorized to use services by the subscriber (and may have their user profile)
Another partyFor example, the calling party in a call, the called party. p g p y p yThey may not be a 3G user.
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Access Domain & InterfacesAccess Domain & Interfaces
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Node BNode B
It provides radio resources for a UMTS networkp
Uses UMTS Channel Allocation to Communicate with the HandsetCommunicate with the Handset.
It provides all the RF processing, enablingIt provides all the RF processing, enabling transmission and reception information to and from the mobile terminalfrom the mobile terminal
This information is encoded using the WCDMA t h ltechnology
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RNC (Radio Network Controller)RNC (Radio Network Controller)
It controls the operation of multiple Node Bs,p p ,
Manages resources such as allocating capacity for data calls andfor data calls, and
Provides critical signaling, e.g., call set-up, plusProvides critical signaling, e.g., call set up, plus switching and traffic routing functionality
All h d h iAll handovers processes, even where moving between cells controlled by different RNCs, are k t ithi th UTRANkept within the UTRAN.
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RNC Terminology© owned by © owned by informa Telecoms
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Further New UTRAN FeaturesFurther New UTRAN Features
W-CDMA
ATM Transport
Flexible bearer support & connection management
Handover functionsHandover functions
Location Determination
Support for procedure and function interworking with GSM BSSGSM BSS
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The Core Network DomainThe Core Network Domain
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Specific Entities in the UMTS R’99 Core Specific Entities in the UMTS R 99 Core Network Architecture
GSM core network elements:MSC, VLR, HLR, AuC and EIR
GSM enhancements (GSM Phase 2+):GSM enhancements (GSM Phase 2+):GPRS to support packet-switching
CAMEL (and other toolkits) as a basis for the VHE
New UMTS-specific enhancementspNew UTRAN and USIM
This new UTRAN can be connected to the GSM Phase 2+ coreThis new UTRAN can be connected to the GSM Phase 2+ core network.
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Th Ci it S it h d D i (1/2)The Circuit-Switched Domain (1/2)
MSC (Mobile Switching Center)( g )Provides the interface between the UTRAN and fixed network
Performs all necessary to handle CS services to/from mobilePerforms all necessary to handle CS services to/from mobile terminal
Performs switching and signaling functions
Impacts the location registration & handover between calls
Gateway MSCGateway MSCProvides routing to the appropriate MSC where a mobile terminal is located after having interfaced with the database within theis located, after having interfaced with the database within the home environment
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Th Ci it S it h d D i (2/2)The Circuit-Switched Domain (2/2)
VLR (Visitor Location Register)( g )Is used by the MSC to retrieve information for MS currently within its area.within its area.
Interworking Function (IWF)An IWF provides the functionality to allow interworking of differing networks, e.g., ISDN, PSDN, and PDNs (protocol conversion).
E.g., the A interface (GSM) and the Iu-CS (UMTS) interface conversion
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HLR AuC and EIR = HSSHLR, AuC, and EIR = HSS
HLR (Home Location Register)Contains subscriber information, and information enabling charging and packet routing of the messages.Subscriber information = IMSI, MSISDN, PDP addresses for GPRS,Subscriber information IMSI, MSISDN, PDP addresses for GPRS, information on service access/restrictions
AuC (Authentication Center)AuC stores data for each subscriber to allow the IMSI to be authenticated and to allow of communication over the radio path.
EIR (Equipment ID Register)EIR (Equipment ID Register)Responsible for storing the International Mobile Equipment IDs (IMEIs)
HSS = HLR + AuC + EIRHSS = HLR + AuC + EIR
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The Packet Switched DomainThe Packet-Switched Domain
The SGSN (Serving GPRS Support Node) = ( g pp )MSC/VLR
Are IP routersAre IP routers Includes a location register function which stores subscription information and location information for ppacket-switched services
The (Gateway GPRS Support Node) = GMSCThe (Gateway GPRS Support Node) GMSCStores subscription information and routing information for each subscriber for which the GGSN has at least one PDPeach subscriber for which the GGSN has at least one PDP context active.The information is used to tunnel packet data destined for a
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pGPRS terminal through to the SGSN
Other Network Entities (1/2)Other Network Entities (1/2)
Short Message Service CenterFor SMS service
Connects to the UMTS Core network via SMS Gateway/Interworking MSC
Serving Mobile Location Center (SMLC)For Location Services
d i hi h UTRAN R di N k C ll (RNC)Located within the UTRAN Radio Network Controller (RNC)
CAMEL Service EnvironmentLocated within the Home Network
Cell Broadcast CenterFor Cell Broadcast ServicesConnects directly to the UTRAN Radio Network Controller (RNC)
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E l ti f Ci it S it h d D iEvolution of Circuit-Switched Domain
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IP Multimedia Subsystem IP Multimedia Subsystem
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Domains in All IP UMTSDomains in All-IP UMTS
The radio access and user domains remain structurally ythe same.
The core network remains divided into circuit and packetThe core network remains divided into circuit and packet switched domains,
With th IP lti di C N t k b t l dd dWith the IP multimedia Core Network subsystem newly added.
The “Service Subsystem” can link into each of the core network domains and the IP multimedia subsystem by means of a “service control point” to the OSA (Open Service Architecture).
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UMTS Core NetworkUMTS Core Network
Core Network Architecture and Functions
The Core Network CS Domain
The Core Network PS Domain
Core Network Transmission
Charging
Network ManagementNetwork Management
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Main Functions of the Core Network Main Functions of the Core Network (1/2)
Transport of User Data: CS and PSp
Mobility Management (MM): CS and PS
Connection Management (CM): CSBearer ManagementBearer ManagementCall Control S l t S iSupplementary ServicesShort Message Service
Session Management (SM): PS
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Main Functions of the Core Network Main Functions of the Core Network (2/2)
Charging: CS and PSg g
Network Management: CS and PS
Interworking with External networks: CS and PS
Service Provision (hosting of Open Service Architecture CAMEL etc ): CS and PSArchitecture, CAMEL etc.): CS and PS
Security: CS and PSy
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CN to UE Control PlaneCN to UE Control Plane
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User and Control Information in CS Domain
MSC: provides the (1) switching functionality and (2) control for (1) setting up, (2) tearing down, and (3) supervising circuits.
The HLR and SCP (SS7 node):Provide support for (1) Mobility and (2) Operator Specific Services.
The VLRProvides support for mobility and is co-located with the MSCProvides support for mobility and is co-located with the MSC.
The control information is passed within SS7 (Signaling System Number 7 protocols) and makes use of theSystem Number 7 protocols), and makes use of the lower layer signaling network.
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SS7 NodesSS7 Nodes
SCP (Service Control Point):( )A database which may control information relevant to routingrouting
SSP (Service Switching Point):Provides the switching functions, and call control functions
STP (Si li T f P i t)STP (Signaling Transfer Point):Is designed to route packets across the network
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User and Control Information in the User and Control Information in the PS Domain
The intermediate routers between SGSN and GGSN route the packets on to the SGSN or GGSNGGSN.
For mobility control and provision of operator y p pspecific services, the GSNs communicate with the HLR and SCP respectivelythe HLR and SCP, respectively.
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Tunneling (Transmission)Tunneling (Transmission)
PDU
(“Header, Tunneling Info”) GTP
(“Header”) UDP/TCP
(“Header IPv4 Address”) (“Fragmentation”) IP
Prepare for Transmission
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Tunneling (Reception)Tunneling (Reception)
Received Data
(“Remove Header”) (“Reassemble”) IP
(“Checksum etc…”) UDP/TCP
(“Remove Header”) GTP
PDU
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Charging (1/2)Charging (1/2)
CS Domain:Time
LocationLocation
Number of Channels
PS d iPS domain:Time
Location
QoS
Data Volume
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Charging PS DomainCharging-PS Domain
In the PS domain, a Charging Gateway Function (CGF) collects charging records which are collected as follows:charging records which are collected as follows:Charging data recorded at SGSN
Usage of the radio interface (amount of data & QoS characterisation)Usage of the radio interface (amount of data & QoS characterisation)Length of time for which PDP addresses where usedUsage of PS domain resourcesLocation of the mobile station
At the GGSN, Destination and source addressesUsage of external data network (amount of data)Length of time for which PDP addresses were usedLength of time for which PDP addresses were used
Another new requirement in UMTS is that such data needs to be available on a real-time basis, to allow real-time and online billing to th
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the user
Th k i f th UMTS O tThe key aims for the UMTS Operator
Minimize the cost & Complexityp y
Maximize the flexibility
Manage equipment supplied by different vendorsvendors
Ensure scalabilityEnsure scalability
Re-use existing standards, and ensure ginteroperability with other networks
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TMN ModelTMN Model
TMN (Telecommunication Management Networks) ( g )standard has been developed by ITU.
This model is used for UMTS network managementThis model is used for UMTS network management
TMN provides:An architecture of Operational Systems and Network elements with defined interfaces between them
Tools to refine the management architecture in a given network management area
C f i hi h b li d i TMNCommon functions which can be applied to various TMN interfaces
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Part 3: WCDMA in UMTSPart 3: WCDMA in UMTS
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OutlinesOutlines
Wideband Code Division Multiple Access (W-p (CDMA) Principle
The Spreading/Despreading Process
UMTS CodesUMTS Codes
Cell Coverage and HandoversCell Coverage and Handovers
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Th S d S t C t (2/2)The Spread Spectrum Concept (2/2)
In Spread Spectrum, the information bandwidth p p ,is “spread” across a wider transmission bandwidth.
To allow the signals from different sources can be distinguished at a receiverbe distinguished at a receiver,
Signals (which coexist within the transmission frequency b d) t b t d i “CODES” hi h h lband) must be separated using “CODES” which have a low cross-correlation with the other codes.Decoding signals using wrong code will simply produceDecoding signals using wrong code will simply produce “NOISE”.
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Direct Sequence CDMADirect Sequence CDMA
W-CDMA is an example of a direct-sequence p qCDMA system.
DS-CDMA is one where user information bits are spread over a wide bandwidth by multiplying p y p y gthis information signal (user data) directly with “CDMA spreading codes” comprised of “Chips”CDMA spreading codes comprised of Chips .
The rate of change of these chips must be higher than the user data rate spreaduser data rate spread
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Spreading Direct SequenceSpreading-Direct Sequence
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W CDMA Key Parameters (1/2)W-CDMA Key Parameters (1/2)
Chip rate = 3.84 Mcpsp pA key difference between UMTS and previous CDMA system, e.g., IS-95/cdmaOne has the chip rate = 1.23 Mc/ssystem, e.g., IS 95/cdmaOne has the chip rate 1.23 Mc/s
Bandwidth = 5 MhzIn WCDMA, the carrier bandwidth = 5 MHz, where IS-95 only uses 1 MHz. 15 MHz licence band provides 3 cell layers.
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W CDMA Key Parameters (2/2)W-CDMA Key Parameters (2/2)
Frame Length = 10 msgIn the Time domain, users are allocated ``frames” of 10 ms duration.duration.
Within a frame, the data rate and spreading factor is constant.constant.
In UMTS, the data rate to change from frame to frame “bandwidth on demand”.bandwidth on demand .
Specified to utilize advanced receiversMulti-user detection and smart adaptive antennas.
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T A M th d FDD & TDDTwo Access Methods: FDD & TDD
FDD (Frequency Division Duplex):Uplink and downlink operate on entirely separate frequency bands (“PAIRED SPECTRUM”).A “DUPLEX SEPERATION” of 190 MHz is used to avoid interference between the two signals.FDD is better suited to covering wide areas with lowerFDD is better suited to covering wide areas with lower transmission rate.
TDD (Time Division Duplex):TDD (Time Division Duplex):Uplink and downlink share the same frequency band.To avoid overlap between uplink and downlink from propagationTo avoid overlap between uplink and downlink from propagation delays, a “GUARD PERIOD” is allocated.TDD is suitable for small cell areas where higher data rates can be
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provided.
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Spreading and Despreading of DS-CDMA (1/2)(1/2)
The operation of spreading:The operation of spreading:Combine the original data with the spreading code, resulting in the spread signal.spread signal.
The rate of change of data in the spread signal is higher than in the original data, and it is equal to the chip rate.g
X-OR function:
1 xor 1 = 0; 1 xor 0 = 1; 0 xor 1 = 1; 0 xor 0 = 01 xor 1 0; 1 xor 0 1; 0 xor 1 1; 0 xor 0 0
The operation of despreading:The same XOR function is applied to the transmitted signal using the same spreading code.
Thi th i i l d t d t th t f h fThis recovers the original data, and returns the rate of change of the data (i.e., bandwidth) to its pre-spreading value.
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Spreading and Despreading of DS-CDMA (2/2)
Data signals are not transmitted as 1s and 0s.g
They are converted into a “bipolar waveform”, +1 and -1.
1 1; 0 11 -1; 0 1
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Spreading Multiple SignalsSpreading Multiple Signals
A Receiver must be able to separate the variousA Receiver must be able to separate the various signals and associate them with the particular
ser ser data and/or control information asuser, user data and/or control information as required.
Different signals are assigned different spreading codes.
“TIME ALIGNMENT” is made between various spreadingTIME ALIGNMENT is made between various spreading codes.
This is most simply illustrated using a case involving twoThis is most simply illustrated using a case involving two data sources.
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96Spreading Multiple Signals
De Spreading Multiple SignalsDe-Spreading Multiple Signals
At the receiver, to reassemble data, the combined waveform signal is de-spread using the specific code assigned to that original set of data.
The de-spread signal is then determined by taking the value of the integration at the “decision point” at the end f h b l i dof each symbol period.
The integrator is then reset to zero at the start of the gnext symbol period.
Spreading Factor = the ratio of transmitted bandwidth toSpreading Factor the ratio of transmitted bandwidth to information bandwidth (chip rate/data rate).
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98De-spreading Multiple Signals
Spreading Factors and CapacitySpreading Factors and Capacity
Capacity limited by (1) Number of users ; (2) p y y ( ) ; ( )Higher data rates
Noise level varies depending on which signal is being despread g p
As the wanted signal is despread, its contributions to the overall “system” noise level need not be considered with yrespect to the despread signal
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Spreading Factors and CapacitySpreading Factors and Capacity
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UMTS CODESUMTS CODESChannelisation Codes and Scrambling Codes have theChannelisation Codes and Scrambling Codes have the same chip rate
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Channelisation CodesChannelisation Codes
The codes are used to separate differentThe codes are used to separate different transmissions from a single source (from UE i li k f N d B i d li k)in uplink, from Node B in downlink)
In the uplink, this means the separation of the physical y(user) data and control and signalling data from the same terminal.
In the downlink, this means the separation of downlink connections (control channels and traffic channels) to different users within one celldifferent users within one cell.
Uplink code lengths: 4 to 256p g
Downlink code lengths: 4 to 512
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OVSF (Orthogonal Variable Spreading F t ) C dFactor) Codes
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The Use of OVSF Codes The Use of OVSF Codes
The Spreading Factor (SF) can be changed (e.g., for variable bit-t i )rate services)
A new spreading code with the new length can be chosen while still remaining orthogonal to the original coderemaining orthogonal to the original code.
The chip-rate remains constant at 3.84 Mcps.
“C d l h ” ill h t d h f th“Code clashes” will occurs where two codes are chosen from the same branch.
Codes on separate branches are “orthogonal” and can be usedCodes on separate branches are orthogonal and can be used simultaneously.
The generations of channelisation codes are based on the OVSFThe generations of channelisation codes are based on the OVSF codes.
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Scrambling Codes (1/2)Scrambling Codes (1/2)
The scrambling codes differentiate signals from different sources.At the receiver, the reverse process occurs, with the i l fi t d d i th bli d dsignal first de-spread using the scrambling code, and
then combined with the channelisation codes.U li k illi f dUplink: million of codesDownlink: limited to up to 512 codesSpreading factor defines the number of channelisation codes per scrambling codeScrambling doesn’t change the chip rate
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Scrambling Codes (2/2)Scrambling Codes (2/2)
WCDMA is described as asynchronous ysince it uses different scrambling codes to separate users from cells.
By contrast, IS-95 is synchronousWithout assigning different scrambling codes instead requiresWithout assigning different scrambling codes instead requires that the application of spreading codes is synchronized with GPS at the BS.
Generated by using Pseudo-Random number sequences known as a PN sequence.sequences known as a PN sequence.
A sequence of binary numbers which appears to be random.
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Cell BreathingCell Breathing
Cell Breathing.Th ff ti i d t ti f i ll dThe effective expansion and contraction of a given cell due to sudden changes in the number of mobile users within the cell.
In order to continue to provide good service quality to users close to the cell site usersquality to users close to the cell site, users further away must be excluded.
This means that the cell must in effect shrink.The users who are further away must then be served by dj t ll b f i ft h dadjacent cells by performing soft handovers.
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Cell BreathingCell Breathingfigure © owned by Informa Telecoms
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Part 4: MM Procedure in UMTSUMTS
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OutlinesOutlines
GSM/GPRS/UMTS NetworkControl Plane for UMTS and GPRS Mobility ManagementUser Plane for UMTS and GPRSService Areas Partition in GPRS and UMTSService Areas Partition in GPRS and UMTSUTRAN TrackingMM FunctionsMM StateMM Context and PDP Context
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GSM/GPRS/UMTS N t k[3 23 060]GSM/GPRS/UMTS Network[3g23.060]
SM SCSMS-GMSC
CEd
SM-SCSMS-IWMSC
CAMEL GSM-SCF
DMSC/VLR HLR
Gd SCF
Ge
Uu GiIuGc
Gs
TE MT UTRAN TEPDN
GrIu
SGSN GGSN
AR
Gn
Gp
TE MT UTRAN TEPDNSGSN GGSN
GaGa
GbTE MT BSS
Gf
Um Gp
GGSN EIRSGSN
GnCGF
BillingSystem
TE MT BSSR
Gf
Si lli I t f
Other PLMN EIRSGSN
111Signalling and Data Transfer Interface Signalling Interface
GPRS NetworkGPRS Network
To be simplified (but may be misleading), GPRS is evolved from GSM by introducing two new core network nodes Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN)Support Node (SGSN) and Gateway GPRS Support Node (GGSN).
Existing GSM nodes (BSS, MSC/VLR, and HLR) are upgraded.
GPRS BSS i t f B T i St ti (BTS) d BGPRS BSS consists of Base Transceiver Station (BTS) and Base Station Controller (BSC) where the BSC is connected to the SGSN through frame relay link.g y
The BTS communicates with the MS through the radio interface Um based on the TDMA technology.
Three operation modes are defined for GPRS MS:Class A MS allows simultaneous CS and PS connections.Class B MS provides automatic choice of CS or PS connection, but only one at a time.Class C MS only supports PS connection
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Class C MS only supports PS connection.
UMTS NetworkUMTS NetworkUMTS is evolved from GPRS by replacing the radio access y p gnetwork.The UTRAN (UMTS Terrestrial Radio Access Network) consists of Node Bs (the 3G term for BTS) and Radio Network ControllersNode Bs (the 3G term for BTS) and Radio Network Controllers(RNCs) connected by an ATM network.The RNC and the Node B serving an MS are called the Serving g gRadio Network System (SRNS).In UMTS, every Node B is connected to an RNC through the Iub interfaceinterface.Every RNC is connected to an SGSN through the IuPS interface, and to an MSC through the IuCS interface.gAn RNC may connect to several RNCs through the Iur interface.Unlike RNCs in UMTS, the BSCs in GPRS/GSM do not connect toUnlike RNCs in UMTS, the BSCs in GPRS/GSM do not connect to each other.The IuCS, IuPS, Iub, and Iur interfaces are implemented on the ATM net ork
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ATM network.
UMTS User EquipmentUMTS User Equipment
The User Equipment (UE; the 3G term for MS) q p ( ; )connects with Node Bs through the radio interface Uu based on the WCDMA (Wideband (CDMA) technology.
Three operation modes are defined for UMTSThree operation modes are defined for UMTS UE:
PS/CS mode UE is equivalent to GPRS Class A MS.PS mode UE is equivalent to GPRS Class C MS.CS mode UE can only attach to the CS domain.
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Core Network EvolutionCore Network Evolution
In terms of the core network evolution from GPRS to UMTS, both SGSN and MSC need to be modified.
Other core network nodes such as HLR (specifically, HLR packet domain subscription data), VLR ( ifi ll VLR d SGSN i ti ) d GGSN(specifically, VLR and SGSN association), and GGSN(specifically, PDP contexts) are basically the same.
The SGSN and the MS are modified (specifically MM and PDP contexts and the related procedures)and PDP contexts and the related procedures).
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C t l Pl f UMTS d GPRS (1/2)Control Planes for UMTS and GPRS (1/2)
(a) Control plane for UMTS Mobility Management(a) Control plane for UMTS Mobility Management
116(b) Control Plane for GPRS Mobility Management
Control Planes for UMTS and GPRS (2/2)Control Planes for UMTS and GPRS (2/2)Unlike GPRS, the LLC layer is not supported in UMTS. In GPRS, reliable communication between MS and SGSN is guaranteed by LLCcommunication between MS and SGSN is guaranteed by LLC.
In UMTS, Radio Resource Control (RRC) protocol is responsible for reliable connection between MS and UTRAN, and Signaling Connection Control Partconnection between MS and UTRAN, and Signaling Connection Control Part(SCCP) is responsible for reliable connection between UTRAN and SGSN.
Specifically, radio resources are managed by RRC exercised between the MS and p y, g ythe UTRAN.
On top of SCCP, the Radio Access Network Application Part (RANAP) protocol p , pp ( ) psupports transparent mobility management signaling transfer between the MS and the CN which are not interpreted by the UTRAN.
RANAP is also responsible for serving RNC relocation, radio access bearer ( RAB) management, and so on.
In both GPRS and UMTS the GPRS Mobility Management (GMM) protocol supports mobility management functionality, which is the focus of this paper. In 3GPP 23 121 GMM for UMTS is also referred to as UMTS MM (UMM)
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3GPP 23.121, GMM for UMTS is also referred to as UMTS MM (UMM).
MM M i b t MS d SGSNMM Messaging between MS and SGSN
In GPRS, the mobility management (MM) messages are y g ( ) gdelivered through the Gb and the Um interfaces.
Specifically, an LLC link provides signaling connection between p y, p g gthe MS and the SGSN in GPRS.
In UMTS, the MM message transmission is performedIn UMTS, the MM message transmission is performed through the Iu and the Uu interfaces.
I UMTS h i li i i f RRC iIn UMTS, the signaling connection consists of an RRC connectionbetween the MS and UTRAN, and an Iu connection (“ one RANAP instance”) between the UTRAN and the SGSN.
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MM Messaging between SGSN and Oth CN N dOther CN Nodes
In both GPRS and UMTS, GSM Mobile Application Partpp(MAP) is used to interface SGSN and the GSM nodes.
For example, Gr for HLR and Gs (the BSSAP+ protocol orFor example, Gr for HLR and Gs (the BSSAP protocol or BSS Application Protocol + ) for MSC/VLR. SGSNs and GGSNs communicate by using the GPRS Tunneling P t l (GTP) th h th G i t fProtocol (GTP) through the Gn interface.
Specifically, a GTP tunnel is established between two GPRS d t d li th k t Thi t l i id tifi d bnodes to deliver the packets. This tunnel is identified by a
tunnel endpoint identifier (TEID), an IP address and a UDP port number.port number.
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User Planes for GPRS and UMTSApplication
E.g., IP,PPP
Relay
E.g., IP,PPP
Relay
RLC
PDCP
MAC
RLC
PDCP
MAC
UDP/IP
GTP-U
AAL5
UDP/IP
L2
GTP-U
UDP/IP
GTP-U
AAL5
UDP/IP
GTP-U
L2
(a) User plane for UMTS
L1 L1 ATM L1
3G-SGSNUTRANMSIu-PSUu Gn Gi
3G-GGSN
ATM L1
(a) User plane for UMTS
Relay
Application
IP IPyGTP-USNDCP
LLC
RLC
SNDCP
LLC
BSSGPRLC BSSGPRelay
IP IP
GTP-U
UDPUDP
NetworkService
MAC
GSM RF L1bis
MAC
GSM RF L1bis
L2
L1
L2
L1
Um Gb Gn GiMS BSS SGSN GGSN
NetworkService
120(b) User Plane for GPRS
Summary: GPRS and UMTS A hit tArchitecture
In both GPRS and UMTS, IMSI is used as the common user Identity, and common MAP signaling is applied to both systems as well as GSM.
Unlike GPRS, UMTS Radio network parameters and radio resources are managed in the UTRANradio resources are managed in the UTRAN.
Link GPRS BSS, the UTRAN does not coordinate MM S Cprocedures that are logically between the MS and CN.
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Concepts of Mobility Management
In order to track the MSs the cells (i e BTSs/Node Bs) in GPRSIn order to track the MSs, the cells (i.e., BTSs/Node Bs) in GPRS /UMTS service area are partitioned into several groups. To deliver services to an MS, the cells in the group covering the MS will page the MS to establish the radio linkMS to establish the radio link.
In the CS domain, cells are partitioned into location areas (LAs). The LA of an MS is tracked by the VLRLA of an MS is tracked by the VLR.
In the PS domain, the cells are partitioned into routing areas (RAs). An RA is typically a subset of an LA The RA of an MS is tracked by theRA is typically a subset of an LA. The RA of an MS is tracked by the SGSN.
In GPRS the SGSN also tracks the cell of an MS in PS connectionIn GPRS, the SGSN also tracks the cell of an MS in PS connection (i.e., when packets are delivered between the MS and the SGSN).
In UMTS the cells in an RA are further partitioned into UTRAN RAsIn UMTS, the cells in an RA are further partitioned into UTRAN RAs(URAs). The URA and the cell of an MS are tracked by the UTRAN.
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Location Areas, Routing Areas, and UTRAN R ti AUTRAN Routing Areas
123
Areas Tracked by the Network N dNodes
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UTRAN Tracking (1/2)UTRAN Tracking (1/2)In UMTS the UTRAN tracking is triggered b theIn UMTS, the UTRAN tracking is triggered by the establishment of the RRC connection. In the MS and the UTRAN an RRC state machine is executedUTRAN, an RRC state machine is executed.
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UTRAN Tracking (2/2)UTRAN Tracking (2/2)
In the RRC Idle mode, no RRC connection is established, and the MS is tracked by the SGSN at the RA level.
When the RRC connection is established, the state moves from RRC Idle to RRC Cell Connected, and the ,MS is tracked by the UTRAN at the cell level.
If for example no PDUs are transmitted before anIf, for example, no PDUs are transmitted before an inactivity timer expires, the state moves from RRC Cell Connected to RRC URA Connected, and the MS isConnected to RRC URA Connected, and the MS is tracked by UTRAN at the URA level.
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MM Functions (1/2)MM Functions (1/2)
The MM functions for PS-based services are(1) PS attach procedure allows an MS to be “known” by the
PS service domain of the network. For example, after the MS is powered on, the PS attach procedure must be executed before the MS can obtain access to the PS services. Note that the term “PS attach” is used in UMTS and the term “GPRS attach” is used in GPRS.Similarly we have the term “CS attach” for UMTS and “IMSISimilarly, we have the term “CS attach” for UMTS and “IMSI attach” for GPRS.
(2) PS detach procedure allows the MS or the network to inform(2) PS detach procedure allows the MS or the network to inform each other that the MS will not access the SGSN-based services.
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MM Functions (2/2)MM Functions (2/2)
(3) Tunneling of non-GSM signaling message ( ) g g g gprocedures support communication between GPRS/UMTS and non-GSM systems (e gGPRS/UMTS and non-GSM systems (e.g., EIA/TIA IS-136).
The SGSN forwards the signaling messages to the non-GSM MSC/VLR using the BSSAP+ protocol in the Gs interfaceinterface.
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MM StatesMM StatesIn GPRS and UMTS an MM finite state machine isIn GPRS and UMTS, an MM finite state machine is exercised in both SGSN and MS to characterize the mobility management activities for the MS. y g
In GPRS, the states in the machine are IDLE, STANDBY and READYSTANDBY and READY.
For UMTS PS service domain, these states are d PMM DETACHED PMM IDLE d PMMrenamed as PMM-DETACHED, PMM-IDLE and PMM-
CONNECTED.
The MM state machines for both GPRS and UMTS are basically the same.
The MM states are stored in the MM contexts maintained by the MS and the SGSN.
129
y
MM State Diagram (MS)MM State Diagram (MS)
130
MM State Diagram (SGSN)MM State Diagram (SGSN)
131
MM and PDP ContextsMM and PDP Contexts
Mobility Management (MM) context provides mobility i f ti f MSinformation of an MS.Packet Data Protocol (PDP) context provides i f ti t t k t d li b t MSinformation to support packet delivery between an MS and the network.Whil MS b i t d ith l PDPWhile an MS may be associated with several PDP contexts, it only has one MM context.Th MM t t i i t i d i MS d SGSNThe MM context is maintained in MS and SGSN. The PDP contexts are maintained in MS, SGSN, and GGSNGGSN.
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MM ContextMM Context
The following fields in the MM context are gmaintained in both GPRS and UMTS SGSN:
IMSI, MM state, P-TMSI, P-TMSI signature,IMSI, MM state, P TMSI, P TMSI signature, International Mobile Equipment Identity (IMEI), Mobile Station ISDN Number (MSISDN)Mobile Station ISDN Number (MSISDN), routing area, VLR number, new SGSN address MS network access capability, authentication triplets, Kc (currently used ciphering key),
l t d i h i l ith b ib d h iselected ciphering algorithm, subscribed charging characteristics, and several flags.
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MM SGSN Context: GPRS vs UMTS (L ti I f ti ) (1/2)(Location Information) (1/2)
GPRS SGSN maintains cell identity (current cell y (in READY state, or the last known cell in STANDBY or IDLE state) and cell identity ageSTANDBY or IDLE state) and cell identity age (time elapsed since the last LLC PDU was received from the MS at the SGSN)received from the MS at the SGSN).
These two fields are not maintained in UMTSThese two fields are not maintained in UMTS SGSN because cell tracking is performed by theserving RNCserving RNC.
134
MM SGSN Context: GPRS vs UMTS (L ti I f ti ) (2/2)(Location Information) (2/2)
UMTS SGSN maintains the service area code (SAC), d th l d ti i th l t SAC i d tand the elapsed time since the last SAC was received at
the SGSN. Th SAC i d t i l id tif i tiThe SAC is used to uniquely identify an area consisting of one or more cells belonging to the same location area. SAC and the location reporting procedure are used in UMTS for location service (LCS) and other services U S o ocat o se ce ( CS) a d ot e se cessuch as emergency calls .These fields are not maintained in GPRS SGSNThese fields are not maintained in GPRS SGSN because the concept of SAC does not exist in GPRS.
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MS MM Context: GPRS vs UMTSMS MM Context: GPRS vs UMTS
Location InformationLocation InformationGPRS MS maintains cell identity.
In UMTS, cell tracking is not conducted at the mobility management layer between the MS and the SGSN.
Thus, cell identity is not maintained in the MM context of the MS. Instead, it is maintained between the MS and the UTRANUTRAN.
Security InformationyUMTS MS maintains extra security parameter CK next.
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PDP SGSN Context: GPRS vs UMTS (1/2)
Core Network to Radio Access Network Connection
Th UMTS i t i th TEID f th I i t f d th IPThe UMTS maintains the TEID for the Iu interface and the IP address of the RNC currently used.
Th t fi ld t i t i d i th GPRS SGSNThese two fields are not maintained in the GPRS SGSN
Radio Resource InformationThe GPRS SGSN maintains radio priority (the RLC/MAC radio priority level for uplink user data transmission).radio priority level for uplink user data transmission).
These fields are not kept in UMTS SGSN.
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PDP SGSN Context: GPRS vs UMTS (2/2)
PDU InformationGPRS SGSN maintains Send N-PDU number (SNDCP sequence number of the next downlink N-PDU to be sent tosequence number of the next downlink N PDU to be sent to the MS), Receive N-PDU number (SNDCP sequence number of the next uplink N-PDU to be received from the MS) k t fl id tifi d t BSS Q S filMS), packet flow identifier and aggregate BSS QoS profile negotiated.
O th th h d UMTS SGSN i t i PDCP SND (thOn the other hand, UMTS SGSN maintains PDCP-SND (the next PDCP sequence number to be sent to the MS) andPDCP-SNU (the next PDCP sequence number expectedPDCP SNU (the next PDCP sequence number expected from the MS).
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MS PDP contextMS PDP context
PDP type, PDP address, PDP state, dynamic yp , , , yaddress allowed,
APN requested, NSAPI, TI,
QoS profile requested QoS profile negotiatedQoS profile requested, QoS profile negotiated, and
A flag
139
MS PDP Context: GPRS vs UMTSMS PDP Context: GPRS vs UMTS
Radio InformationThe GPRS MS maintains radio priority.
I UMTS th di i it f d t d li i d t i dIn UMTS, the radio priority for data delivery is determined by QoS profile, and the radio priority is not kept separately in the MS.in the MS.
PDU Delivery InformationGPRS MS maintains BSS packet flow identifier, Send N-PDU number and Receive N-PDU number.
UMTS MS maintains PDCP-SND and PDCP-SNU.
140
Relationship between MM States & C t t (1/3)Contexts (1/3)
The status of an MM/PDP context is affected by ythe MM states
IDLE (PMM DETACHED)IDLE (PMM-DETACHED)The PDP context in the GGSN is deleted. The MM and PDP contexts in MS and SGSN may or may not be deleted. If the MM state moves from STANDBY/PMM IDLE to IDLE/MMIf the MM state moves from STANDBY/PMM-IDLE to IDLE/MM-DETACHED because the mobile reachable timer expires (e.g., the MS is temporarily out of the GPRS/UMTS coverage), then these two contexts shall not be deletedtwo contexts shall not be deleted.In this case, the location and routing information is stale.
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Relationship between MM States & C t t (2/3)Contexts (2/3)
STANDBY (PMM-IDLE)STANDBY (PMM IDLE)In the STANDBY/PMM-IDLE state, valid MM contexts are maintained in the MS and the SGSNmaintained in the MS and the SGSN.
In this state, the PDP context can be activated and deactivateddeactivated.
In UMTS, when the PDP context is activated in this state, no Iu/radio connection is established between the MS and theIu/radio connection is established between the MS and the network because PDU delivery is not allowed in this state.
In GPRS the LLC link is connectedIn GPRS the LLC link is connected.
142
Relationship between MM States & C t t (3/3)Contexts (3/3)
READY (PMM-CONNECTED)( )In the READY/PMM-CONNECTED state, valid MM contexts are maintained in the MS and the SGSN.are maintained in the MS and the SGSN.
As in the STANDBY/PMM-IDLE state, the MS may initiate PDP context activation and deactivation.PDP context activation and deactivation.
In this state, the signaling connection is established in UMTS.UMTS.
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