UMTS (Universal Mobile Telecommunication System)
• Network Architecture and Elements
• Protocol Architecture (packet switched domain)
• QoS Architecture
• Modes and States
• Important References
UMTS Networks 2Andreas Mitschele-Thiel 6-Apr-06
UMTS/GSM Network Architecture
GPRS Core(PacketSwitched)
SGSN
GGSN
Internet
GSMRAN
Base stationBase stationcontroller
Base station
Base station
UTRAN
Radio networkcontroller
node Bnode B
node B
MSC
PSTN
GSM Core (Circuit switched)
HLRAuCEIR
GMSC
UMTS Networks 3Andreas Mitschele-Thiel 6-Apr-06
UM
TS N
etw
ork
Arc
hite
ctur
eB
asic
Con
figur
atio
n, R
elea
se 3
BSS
BSC
RNS
RNC
CN
Node B Node B
A IuPS
Iur
Iub
Uu
MSC SGSN
Gs
GGSN GMSC
GnHLR
Gr
GcC
D
E
AuC H
EIR
F Gf
GiPSTN
IuCSGb
VLR B
Gp
VLR G
BTS BTS
Um
RNC
Abis
MSC
B
PSTNPSTN
cellSour
ce:
3GPP
23.
002-
3.4.
0
Circ
uit
switc
hed
CN Packet switched CN
GSM RAN
UTRAN
UMTS Networks 4Andreas Mitschele-Thiel 6-Apr-06
Logical Architecture of Packet-Switched Part
Source: 3GPP 23.060-3.8.0
Gf
Uu
Um
D
Gi
Gn
IuGc
CE
Gp
Gs
Signalling and Data Transfer Interface Signalling Interface
MSC/VLR
TE MT UTRAN TEPDN
(Packet Data Network)
GrIu
HLR
Other PLMN
SGSN
GGSN
Gd
SM-SC SMS-GMSC
SMS-IWMSC
GGSN
EIR SGSN
GnCGF
GaGa
BillingSystem
GbTE MT BSS
R
AR
CAMEL GSM-SCF
Ge AUC
H
GSM
UMTS Networks 5Andreas Mitschele-Thiel 6-Apr-06
Home Location Register (HLR)Home (primary) data base in charge of the management of mobile subscribers
Basic information:• International Mobile Subscriber Identity (IMSI)• CS subscription information
– one or more Mobile Station International ISDN number(s) (MSISDN)• PS subscription information
– zero or more Packet Data Protocol (PDP) address(es)– permission for GGSN to dynamically allocate PDP addresses for a
subscriber• Location information enabling the charging and routing of calls towards
the MSC or SGSN where the MS is registered (e.g. VLR Number)
Authentication Centre (AuC)Stores data for each mobile subscriber
– to allow the International Mobile Subscriber Identity (IMSI) to be authenticated and
– to allow ciphered communication over the radio path The AuC communicates solely with its associated HLR (H-interface)
UMTS Networks 6Andreas Mitschele-Thiel 6-Apr-06
Visitor Location Register (VLR)(Secondary) data base supporting the management of mobilesubscribers currently located within its VLR area
Motivation: minimize load for HLR (i.e. of the primary data base)
Tasks:• control MSs roaming in an MSC assigned to it• exchange information with HLR to allow the proper handling of calls
Information maintained by VLR (for call handling):– International Mobile Subscriber Identity (IMSI)– Mobile Station International ISDN number (MSISDN)– Mobile Station Roaming Number (MSRN)– Temporary Mobile Subscriber Identity (TMSI), if applicable– location area where the mobile station has been registered– the last known location and the initial location of the MS– supplementary service parameters attached to the mobile subscriber
(received from the HLR)
UMTS Networks 7Andreas Mitschele-Thiel 6-Apr-06
Mobile-services Switching Centre (MSC)
MSC: an exchange performing all the switching and signalling functions (CS only) for mobile stationsMSC controls mobile-originated and mobile-terminated CS calls
Functions– call management– mobility management (handling attach and authentication)– subscriber administration– CS data services (FAX, modem)– supplementary call services (call forwarding, etc.) – maintenance of charging data (for radio network usage)– SS7-based signaling transport
Main difference to an exchange in a fixed network: deal with mobility (e.g. location registration, handover)
Gateway MSC (GMSC)– Provides interconnection between the UMTS core network and external
PSTN/ISDN networks
UMTS Networks 8Andreas Mitschele-Thiel 6-Apr-06
GPRS Support Node (GSN) GSNs constitute the interface between the radio access network and the fixed networks for packet switched services (similar to MSC for CS calls)
Serving GSN (SGSN)– session management– mobility management– subscriber database management (interface with HLR)– maintenance of charging data (for radio network usage)– IP-based transport of user data between SGSN and the UTRAN– IP- or SS7-based signaling transport
Gateway GSN (GGSN)– gateway for UMTS packet service to external data networks (e.g. the
Internet)– IP interface towards SGSN– performs user data screening and security– maintenance of charging date (for external data network usage)
UMTS Networks 9Andreas Mitschele-Thiel 6-Apr-06
Other CN entitiesEquipment Identity Register (EIR)– Logical entity storing the International Mobile Equipment Identities (IMEIs)
SMS Gateway MSC (SMS-GMSC)– gateway between Short Message Service Center and PLMN– deliver SMSs from service center to MS
SMS Interworking MSC (SMS-IWMSC)– gateway between PLMN and Short Message Service Center – deliver SMSs from MS to service center
Interworking Function (IWF)– associated with MSC– supports interworking of PLMN with fixed networks, e.g. ISDN, PSTN, PDN
(protocol conversion)Border Gateway (BG)– PS gateway to other PLMNs– firewall functionality
Charging Gateway Functionality (CGF) – collects charging records from SGSNs and GGSNs
UMTS Networks 10Andreas Mitschele-Thiel 6-Apr-06
Radio Network Subsystem (RNS)Provide access to the UMTS terrestrial radio interface
RNS
RNC
RNS
RNC
Core Network
Node B Node B Node B Node B
Iu Iu
Iur
Iub IubIub Iub
UTRAN
Radio Network Controller (RNC)• (Radio) mobility management• Management of radio resources
Base Station (Node B)• Radio coverage of cells• Physical layer processing
UMTS Networks 11Andreas Mitschele-Thiel 6-Apr-06
Dedicated Channels – Soft and Softer Handover
RNS
RNC
RNS
RNC
Core Network
Node B Node B Node B Node B
Iu Iu
Iur
Iub IubIub Iub
UTRAN
UE
SRNCDRNC
Softer handover: maximum ratio combiningin node B
Soft handover: radio frame selection (layer 1) in SRNC (and DRNC)
UMTS Networks 12Andreas Mitschele-Thiel 6-Apr-06
Shared Channels
RNS
RNC
RNS
RNC
Core Network
Node B Node B Node B Node B
Iu Iu
Iur
Iub IubIub Iub
UTRAN
UE 1
SRNCDRNC
UE 2
shared channel
SRNC
UMTS Networks 13Andreas Mitschele-Thiel 6-Apr-06
Roles of Radio Network Controllers (RNCs)Serving RNC (SRNC)• A role an RNC can take with respect to a specific connection between an
UE and UTRAN• There is one Serving RNC for each UE that has a connection to UTRAN• The Serving RNC is in charge of the RRC connection between a UE and
the UTRAN• The Serving RNC terminates the Iu for this UE
Drift RNC (DRNC)• A role an RNC can take with respect to a specific connection between a
UE and UTRAN• An RNC that supports the Serving RNC with radio resources when the
connection between the UTRAN and the UE need to use cell(s) controlled by this RNC
UMTS Networks 14Andreas Mitschele-Thiel 6-Apr-06
Mobile Station (MS)
ITU-T Recommendyer UE
Mobile Equipment (ME) Mobile Termination (MT)
RTAF
Cu
Access Network
UuTerminal Equipment (TE)
USIM
Mobile Equipment (ME)radio transmission and application
Terminal Adaptation Functions (TAF)(service dependent)• mapping of terminal requests on
network capabilities• flow control/rate adaptations
Terminal Equipment (TE)supports for end-to-end application functions necessary for the operation of the access protocols by the user, e.g. a laptop
UMTS Subscriber Identity Module (USIM)user identitycontains data and procedures to unambiguously and securelyidentify itself
Mobile Termination (MT)functions for radio transmissionand management of the radio interface, e.g. the handset
Mobile station (MS)/User Equipment (UE)physical equipment used by a PLMN subscriber
UMTS Networks 15Andreas Mitschele-Thiel 6-Apr-06
MS-RNS/BSS-SGSN-GGSN – Control Plane
UDP
L2
L1
IP
L2
L1
IP
UDP
Gn or Gp
GSN GSN
GTP-C GTP-C
RLC
RRC
L1
GM M /SM / SM S
RRC
M AC
ATM
RANAP
AAL5
Relay
ATM
AAL5
3G SGSNRNSM SIu-PsUu
RLC SCCP
SignallingBearer
M AC
L1
SignallingBearer
RANAP
SCCP
GM M /SM / SM S
Protocol Architecture (PS Domain)
UMTS Networks 16Andreas Mitschele-Thiel 6-Apr-06
MS-RNS-SGSN – Control Plane
GMM (GPRS Mobility Management):– GMM supports mobility
management functionality such as attach, detach, security, and routing area update
SM (Session Management):– SM supports PDP context
activation and deactivation
SMS supports short message service
GTP-C (GPRS Tunneling Protocol for Control plane):– establish, manage and release of
GTP tunnels
Source: 3GPP 23.060-4.1.0
RANAP (Radio Access Network Application Protocol): – transport of higher-layer signalling– handling of signalling between the
3G-SGSN and UTRAN– management of the GTP connections
on the Iu interface
RRC (Radio Resource Control):– Information Broadcast– RRC connection management
(setup, release, reconfiguration)– Radio Bearer management (setup,
release, reconfiguration)– Management of radio resources for
the RRC connection– RRC connection mobility functions– Paging/notification
UMTS Networks 17Andreas Mitschele-Thiel 6-Apr-06
User Plane Bearer Services – Overview
TE MT UTRAN CN IuEDGENODE
CNGateway
TE
UMTS
End-to-End Service
TE/MT LocalBearer Service
UMTS Bearer Service External BearerService
UMTS Bearer Service
Radio Access Bearer Service CN BearerService
BackboneBearer Service
Iu BearerService
Radio BearerService
UTRAFDD/TDD
Service
PhysicalBearer Service
UMTS Networks 18Andreas Mitschele-Thiel 6-Apr-06
Bearer Services – Analogy with Public Transportation
TE MT UTRAN CN IuEDGENODE
CNGateway
TE
UMTS
End-to-End Service
TE/MT LocalBearer Service
UMTS Bearer Service External BearerService
UMTS Bearer Service
Radio Access Bearer Service CN BearerService
BackboneBearer Service
Iu BearerService
Radio BearerService
UTRAFDD/TDD
Service
PhysicalBearer Service
cab: appartment to bus station
walk to cab
Bus: bus station to railway station
railway: station to station
combo ticket: cab and bus
combo ticket for rail, bus and cab:single ticket, single reservation, same service everywhere
cab with driver bus with driver
For each bearer: • specific attributes (delay,
bandwidth, guarantees, etc.• specific reservation
mechanism
train with driver, ...
UMTS Networks 19Andreas Mitschele-Thiel 6-Apr-06
MS-RNS/BSS-SGSN-GGSN – User Plane
L1
RLC
PDCP
MAC
E.g., IP,PPP
Application
L1
RLC
PDCP
MAC
ATM
UDP/IP
GTP-U
AAL5
Relay
L1
UDP/IP
L2
GTP-U
E.g., IP,PPP
3G-SGSNUTRANMSIu-PSUu Gn Gi
3G-GGSN
ATM
UDP/IP
GTP-U
AAL5
L1
UDP/IP
GTP-U
L2
Relay
Source: 3GPP 23.060-4.1.0
UMTS Networks 20Andreas Mitschele-Thiel 6-Apr-06
MS-RNS-SGSN-GGSN – User Plane
L1
RLC
PDCP
MAC
E.g., IP,PPP
Application
L1
RLC
PDCP
MAC
ATM
UDP/IP
GTP-U
AAL5
Relay
L1
UDP/IP
L2
GTP-U
E.g., IP,PPP
3G-SGSNUTRANMSIu-PSUu Gn Gi
3G-GGSN
ATM
UDP/IP
GTP-U
AAL5
L1
UDP/IP
GTP-U
L2
Relay
GTP-U (GPRS Tunneling Protocol for User plane):• tunneling of user data between UTRAN and the SGSN• tunneling between the GSNs in the backbone network• encapsulation of all PDP PDUs
Source: 3GPP 23.060-4.1.0
UMTS Networks 21Andreas Mitschele-Thiel 6-Apr-06
MS-RNS-SGSN-GGSN – User Plane
L1
RLC
PDCP
MAC
E.g., IP,PPP
Application
L1
RLC
PDCP
MAC
ATM
UDP/IP
GTP-U
AAL5
Relay
L1
UDP/IP
L2
GTP-U
E.g., IP,PPP
3G-SGSNUTRANMSIu-PSUu Gn Gi
3G-GGSN
ATM
UDP/IP
GTP-U
AAL5
L1
UDP/IP
GTP-U
L2
Relay
PDCP (Packet Data Convergence Protocol):
• provides protocol transparency (wrt the underlying radio-interface protocols) for higher-layer protocols
• support for e.g., IPv4, PPP and IPv6 (easy introduction of new higher-layer protocols)
• compression of control information(header compression)
Source: 3GPP 23.060-4.1.0
UMTS Networks 22Andreas Mitschele-Thiel 6-Apr-06
UMTS Protocol Architecture (packet switched)
Q2150.1
SGSNSGSNRNSRNS
Control Plane User Plane Transport Plane CommonControl Plane User Plane Transport Plane Common
MM
SM
MAC
Phy-up
PHY
codec
RRC
RLC
PMM
SM
MAC
Phy-up
PHY
RRC
IP
PDCP
RLC
AAL5
RLC
MAC
RRC
AAL5
SSCF
SCCP
FP
SSCOP
MTP3-b
SSCF-N
SCCP
RANAP
RRC
ATM
STM-1
GTP-U
UDP
PDCP
IP
RLC
MAC
Phy-up
AAL5PHY SSCOP
MTP3B
AAL5
SSCF
Q2150.1
Q2150.1
Iu UP
ATM
E1
AAL2
SSCOP
MTP3B
AAL5
SSCF
SCCP
SM
MM
RANAP
SSCOP
MTP3-b
SSCF-N
SCCP
PMM
SM
ATM
STM-1
AAL5
IP
GTP-U GTP-C
UDP
L1
L2
SSCOP
MTP3B
AAL5
SSCF
Q2150.1
Q2150.1
IP
GTP-C
L1
GTP-U
UDP
L2
IP
GGSNGGSNUu Iups Gn
UMTS Networks 23Andreas Mitschele-Thiel 6-Apr-06
UMTS Protocol Architecture (packet switched):The complete picture
Q2150.1
SGSNSGSNRNCRNCNode BNode B
Control Plane User Plane Transport Plane CommonControl Plane User Plane Transport Plane Common
MM
SM
MAC
Phy-up
PHY
codec
RRC
RLC
PMM
SM
MAC
Phy-up
PHY
RRC
IP
PDCP
RLC
SSCOP
NBAP
AAL5
SSCOP
ALCAP
AAL5
SSCF SSCF FP
AAL2 AAL2 AAL5 AAL5
SSCF
RLC
MAC
Phy-up SCCP
FP
RRC
ATM
E1
NBAP
AAL5 AAL2
SSCOP
MTP3-b
SSCF-N
SCCP
RANAP
RRC
ATM
STM-1
GTP-U
UDP
PDCP
ALCAP
STC.2
SSCF-UNI
SSCOP
IP
RLC
MAC
Phy-up
FP
AAL5
ATM
E1
FP
AAL2
SSCOP
ALCAP
AAL5
SSCOP
NBAP
AAL5
SSCF SSCF
PHY
ATM
E1/ STM-1
AAL2 AAL5
NBAP
PHY
ALCAP
SSCOP
STC.2
SSCF-UNIFP
SSCOP
MTP3B
AAL5
SSCF
Q2150.1
Q2150.1
Iu UP
ATM
E1
AAL2
SSCOP
MTP3B
AAL5
SSCF
SCCP
SM
MM
RANAP
SSCOP
MTP3-b
SSCF-N
SCCP
PMM
SM
ATM
STM-1
AAL5
IP
GTP-U GTP-C
UDP
L1
L2
SSCOP
MTP3B
AAL5
SSCF
Q2150.1
Q2150.1
IP
GTP-C
L1
GTP-U
UDP
L2
IP
GGSNGGSNUu Iub Iups Gn
UMTS Networks 24Andreas Mitschele-Thiel 6-Apr-06
Rad
io P
roto
col A
rchi
tect
ure
L3
cont
rol
cont
rol
cont
rol
cont
rol
Logical Channel
Transport Channels
C-plane signalling U-plane information
PHY
L2/MAC
L1
RLC
DCNt GC
L2/RLC
MAC
RLC RLC
RLC RLC
RLC RLC
RLC
Duplication avoidance
UuS boundary
BMC L2/BMC
control
PDCPPDCP L2/PDCP
DCNt GC
Radio Bearers
RRC
Source: 3GPP 25.301-4.1.0
Radio Access BearersAS control plane SAPs
UMTS Networks 25Andreas Mitschele-Thiel 6-Apr-06
L3
cont
rol
cont
rol
cont
rol
cont
rol
Logical Channel
Transport Channels
C-plane signalling U-plane information
PHY
L2/MAC
L1
RLC
DCNt GC
L2/RLC
MAC
RLC RLC
RLC RLC
RLC RLC
RLC
Duplication avoidance
UuS boundary
BMC L2/BMC
control
PDCPPDCP L2/PDCP
DCNt GC
Radio Bearers
RRC
Radio Access BearersAS control plane SAPsPhysical Layer – Functions
• Macrodiversity distribution/combining and soft handover execution• Error detection on transport channels and indication to higher layers (CRC)• FEC encoding/decoding and interleaving/deinterleaving of transport channels• Multiplexing of transport channels and demultiplexing of coded composite
transport channels• Modulation and spreading/demodulation and despreading of physical channels• Frequency and time (chip, bit, slot, frame) synchronisation• Measurements and indication to higher layers (e.g. frame error rate, signal-to-
interference ratio, interference power, transmit power, etc.)• Power control• RF processing
UMTS Networks 26Andreas Mitschele-Thiel 6-Apr-06
L3
cont
rol
cont
rol
cont
rol
cont
rol
Logical Channel
Transport Channels
C-plane signalling U-plane information
PHY
L2/MAC
L1
RLC
DCNt GC
L2/RLC
MAC
RLC RLC
RLC RLC
RLC RLC
RLC
Duplication avoidance
UuS boundary
BMC L2/BMC
control
PDCPPDCP L2/PDCP
DCNt GC
Radio Bearers
RRC
Radio Access BearersAS control plane SAPsMedium Access Control (MAC) – Functions
• Mapping between logical channels and transport channels• Selection of appropriate Transport Format for each Transport Channel
depending on instantaneous source rate• Priority handling (multiplexing) between data flows of one UE (MAC-d)• Priority handling (scheduling) between different UEs (MAC-c/sh)• Identification of UEs on common transport channels• Multiplexing/demultiplexing of upper layer PDUs on transport channels• Traffic volume measurement• Transport channel type switching (controlled by RRC)• Ciphering for transparent RLC mode
UMTS Networks 27Andreas Mitschele-Thiel 6-Apr-06
L3
cont
rol
cont
rol
cont
rol
cont
rol
Logical Channel
Transport Channels
C-plane signalling U-plane information
PHY
L2/MAC
L1
RLC
DCNt GC
L2/RLC
MAC
RLC RLC
RLC RLC
RLC RLC
RLC
Duplication avoidance
UuS boundary
BMC L2/BMC
control
PDCPPDCP L2/PDCP
DCNt GC
Radio Bearers
RRC
Transport Services• Transparent data transfer (TM)
– segmentation/reassembly • Unacknowledged data transfer (UM)
– error detection• Acknowledged data transfer (AM)
– guaranteed delivery (error detection and correction)
Radio Link Control (RLC)
UMTS Networks 28Andreas Mitschele-Thiel 6-Apr-06
RLC – Functions
• Transfer of user data (AM, UM, TM)• Segmentation and reassembly (RLC PDU size adapted to transport
format)• Concatenation• Padding
• Sequence number check (UM mode)• Duplicate RLC PDUs detection• In-sequence delivery of upper layer PDUs• Error correction (e.g. selective-repeat, go-back-n, stop-and-wait)
• Flow control between RLC peers• SDU discard• Protocol error detection and recovery• Exchange of status information between peer RLC entities• Ciphering (non-transparent mode)• Suspend/resume and stop/continue of data transfer• Re-establishment of AM/UM RLC entity
Convert variable-size higher layer PDUs into fixed-size
RLC PDUs (TBs)
Convert radio link errors into packet
loss and delay
Avoid Tx and Rx buffer overflows or
protocol stalling
UMTS Networks 29Andreas Mitschele-Thiel 6-Apr-06
L3
cont
rol
cont
rol
cont
rol
cont
rol
Logical Channel
Transport Channels
C-plane signalling U-plane information
PHY
L2/MAC
L1
RLC
DCNt GC
L2/RLC
MAC
RLC RLC
RLC RLC
RLC RLC
RLC
Duplication avoidance
UuS boundary
BMC L2/BMC
control
PDCPPDCP L2/PDCP
DCNt GC
Radio Bearers
RRC
Radio Resource Control (RRC)
UMTS Networks 30Andreas Mitschele-Thiel 6-Apr-06
RRC – Interaction with Lower Layers
R R C R R C
R L C R L C
Radio Resource Assignment [Code, Frequency, TS, TF Set, Mapping, etc.]
Measurement Report
RLC retransmission control
L 1 L 1
U T R A N U E
Con
trol
Mea
sure
men
ts
Con
trol
Mea
sure
men
ts
Con
trol
Mea
sure
men
ts
Con
trol
Mea
sure
men
ts
M A C M A C
Con
trol
Con
trol
UMTS Networks 31Andreas Mitschele-Thiel 6-Apr-06
RRC – Functions RRC handles the control plane signaling of layer 3 between the UEs and UTRAN:
- Broadcast of information provided by the non-access stratum (Core Network) - Broadcast of information related to the access stratum- Establishment, re-establishment, maintenance and release of RRC
connections- Establishment, reconfiguration and release of Radio Bearers- Assignment, reconfiguration and release of radio resources for the RRC
connection- RRC connection mobility functions- Paging/notification- Routing of higher layer PDUs- Control of requested QoS- UE measurement reporting and control of the reporting- Outer loop power control- Control of ciphering- Arbitration of radio resources on uplink DCH- Initial cell selection and reselection in idle mode- Integrity protection- Control of Cell Broadcast Service (CBS)
UMTS Networks 32Andreas Mitschele-Thiel 6-Apr-06
QoS ArchitectureBasics of QoSQoS attributes:
– data rate– error rate– delay– delay variation
How can the system ensure certain QoS attributes?– reservation of „dedicated“ resources for a connection (e.g. CS voice,
IntServ/RSVP)– differentiation of the use of a shared resource by a connection (e.g.
DiffServ)
Basic functions to provide QoS– admission control (possibly including resource reservation)– traffic classification– traffic conditioning (traffic shaping and policing)– scheduling– overload control
UMTS Networks 33Andreas Mitschele-Thiel 6-Apr-06
Bearer Services – Supported End User QoSSummary of applications in terms of requirements
Errortolerant
Errorintolerant
Conversational(delay <<1 sec)
Interactive(delay approx.1 sec)
Streaming(delay <10 sec)
Background(delay >10 sec)
Conversationalvoice and video Voice messaging Streaming audio
and video Fax
E-mail arrivalnotificationFTP, still image,
paging
E-commerce,WWW browsing,Telnet,
interactive gamesAcce
ptab
le e
rror
rate
Delays requirements
UMTS Networks 34Andreas Mitschele-Thiel 6-Apr-06
QoS Architecture (user plane)
ResourceManager
Mapper
Classif
Cond.
ResourceManager
ResourceManager
Mapper
ResourceManager
Mapper
ResourceManager
ResourceManager
Cond.
Classif
Cond.
MT GatewayCN EDGEUTRAN
BB network serviceIu network serviceUTRA phys. BS
data flow with indication of direction
TE Ext.Netw.
Local BS External BS
Classification function (Class.) assigns user data units received from the external bearer service to the appropriate UMTS bearer service according to the QoS requirements of each user data unit
Traffic conditioner (Cond.) MT: provides conformance of the uplink user data traffic with the QoS attributes of the UMTS bearer serviceGateway: provide conformance of the downlink user data traffic with the QoS attributes of the UMTS bearer service
Mapping function marks each data unit with the specific QoS indication related to the bearer service performing the transfer of the data unit
Resource managers distribute its resources between all bearer services requesting transfer of data units on these resources (scheduling, etc. to provide QoS attributes) Sources: 3GPP TS 23.107-5.3.0, TR 23.907-1.2.0
UMTS Networks 35Andreas Mitschele-Thiel 6-Apr-06
QoS Architecture (control plane)
Transl. Transl.
Adm.Contr
RABManager
UMTS BSManager
UMTS BSManager
UMTS BSManager
Subscr.Control
Adm./Cap.Control
MT GatewayCN EDGEUTRAN
Ext.ServiceControl
LocalServiceControl
Iu BSManager
Radio BSManager
Iu NSManager
UTRAph. BS M
Radio BSManager
UTRAph. BS M
Local BSManager
Adm./Cap.Control
Adm./Cap.Control
Adm./Cap.Control
Iu BSManager
Iu NSManager
CN BSManager
Ext. BSManager
CN BSManager
service primitive interface
BB NSManager
BB NSManager
protocol interface
TE Ext.Netw.
Source: 3GPP TS 23.107-5.3.0, TR 23.907-1.2.0
QoS management functions for UMTS bearer service (control plane)establishment and the modification of a UMTS bearer servicesignalling/negotiation with the UMTS external services establishment or modification of all UMTS internal services with the QoS
UMTS Networks 36Andreas Mitschele-Thiel 6-Apr-06
convertion between external service signalling and internal service primitives and attributes
Check if the network entity supports the requested service and the availability of required resourcesCheck if the network entity supports the requested service and the availability of required resources
QoS Architecture (control plane)convertion between external service signalling and internal service primitives and attributes
verification of administrative rights for using the service
signalling between each other and with external instances to establish or modify a UMTS bearer service and ext. services
translation of RAB service attributes into radio bearer service and Iu bearer service attributes
provision of bearer services with the required attributes
Transl. Transl.
Adm.Contr
RAB Manager
UMTS BS Manager
UMTS BS Manager
UMTS BS Manager
Subscr.Control
Adm./Cap.Control
MT GatewayCN EDGEUTRAN
Ext. Service Control
Local Service Control
Iu BS Manager
Radio BS Manager
Iu NS Manager
UTRA ph. BS M
Radio BS Manager
UTRA ph. BS M
Local BS Manager
Adm./Cap. Control
Adm./Cap.Control
Adm./Cap. Control
Iu BS Manager
Iu NS Manager
CN BS Manager
Ext. BS Manager
CN BS Manager
service primitive interfaceprotocol interface
BB NS Manager
BB NS Manager
TE Ext. Netw.
UMTS Networks 37Andreas Mitschele-Thiel 6-Apr-06
QoS ParametersUMTS Bearer Service Attributes (MT to GGSN)
– Traffic class [‘conversational’, ’streaming’, ’interactive’, ’background’]
– Maximum bitrate [kbps]
– Guaranteed bitrate [kbps]
– Delivery order [y/n]
– Maximum SDU size [bits]
– SDU format information [bits] (needed for efficient RLC TM operation)
– Error rate [erroneous SDUs, bit errors]
– Transfer delay [s]
– Traffic handling priority
– Allocation/Retention Priority
Similar QoS attributes are used for Radio Access Bearer
UMTS Networks 38Andreas Mitschele-Thiel 6-Apr-06
QoS Parameters
Traffic class Conversational class
Streaming class Interactive class Background class
Maximum bitrate X X X X
Delivery order X X X X
Maximum SDU size
X X
SDU format information
X X
Reliability X X X X
Transfer delay X X
Guaranteed bit rate
X X
Traffic handling priority
X
Allocation/Retention priority
X X X X
UMTS bearer attributes defined for each bearer class
Source: 3GPP TR 23.907-1.2.0
UMTS Networks 39Andreas Mitschele-Thiel 6-Apr-06
Mobility, Session and Radio Resource Management (PS mode)
UE mode
HLR GGSNSGSN
RNC
UE
RRC connection
Signaling connection
PMM state (detached, idle, connected)
SM: PDP context (active, inactive)
UMTS Networks 40Andreas Mitschele-Thiel 6-Apr-06
GPRS Mobility Management States
PM M-DET ACHED
PS Attach
PS S ignalling Connection R elease
PS S ignalling Connection Establish
PS Detach
PM M - CONNECTED PM M -IDLE
Detach, PS Attach Reject,RAU Reject
PM M-DET ACHED
PS Detach
PM M -CONNECTED
Serving RNCrelocation
3G -SG SN M M States M S M M States
S M-ACT IVE or INACT IVE
S M-ACT IVE or INACT IVE
S M-ACT IVE or INACT IVE
S M-ACT IVE or INACT IVE
Detach, PS A ttach Reject,RAU Reject PS A ttach
PS S ignalling Connection Establish
PS S ignalling Connection R elease
PM M -IDLE
Source: 3GPP 23.060-4.1.0
Paging only(no signalingconnection between MSand SGSN)
Signalingconnectionbetween MS and SGSN(addressingby U-RNTI)
UMTS: PMM – Packet Mobility ManagementGSM: GMM – GPRS Mobility Management
UMTS Networks 41Andreas Mitschele-Thiel 6-Apr-06
Radio Link, RRC Connection, Signaling Connection
RNS
RNC
RNS
RNC
Core Network
Node B Node B Node B Node B
Iu Iu
Iur
Iub IubIub Iub
UTRAN
UEradio link
RRC connection -> connected mode
signaling connection
SRNC
RRC connections and signaling connections are logical links
UMTS Networks 42Andreas Mitschele-Thiel 6-Apr-06
UE Modes and Mobility Management
Idle mode (no RRC connection; paging area is known; paging needed)– UE is identified by non-access stratum identities such as IMSI, TMSI
and P-TMSI. – UTRAN has no own information about the individual UEs in idle mode– UTRAN can only address e.g. all UEs in a cell or all UEs monitoring a
specific paging occasion
Connected mode (RRC connection, RNTI, cell or URA is known)– connected mode is entered when the RRC connection is established– RRC connection is established between UE and SRNC– UE is assigned a radio network temporary identity (U-RNTI and
possibly a C-RNTI) to be used as UE identity on common transport channels (RACH, FACH, PCH)
– connected mode does not require assignment of physical channel resources (cell_FACH or URA_PCH state)
UMTS Networks 43Andreas Mitschele-Thiel 6-Apr-06
Fundamental Difference Between CS and PS CommunicationConnection (e.g. voice, CS data) • clearly defined start and end • no burstiness
minutes
connectionsetup
connectionrelease
Packet session (e.g. web surfing, fleet management, location services)• start and end times are typically unknown to the UMTS system• traffic is highly bursty
hours
seconds
Differences requires different solutions to• mobility mgmt and• communication mgmt
UMTS Networks 44Andreas Mitschele-Thiel 6-Apr-06
Session Management: States of PDP Context
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
The PDP state indicates whether data transfer is enabled for that PDP address and TFT or not
Reference: 3G 23.060, ch 9
GPRS subscription
PDP address(IP address)
PDP context(QoS attributes)
PDP stateinactive
PDP stateactive
UMTS Networks 45Andreas Mitschele-Thiel 6-Apr-06
Deactivate PDP Context or MM state change to IDLE
or PMM-DETACHED
Activate PDPContext
PDP ContextINACTIVE
PDP ContextACTIVE
Inactive state:– no valid routing or mapping
information to process data related to PDP address
-> no data transfer-> no updates due to location
changes (even in GPRS-attached state)
PDP context activation (transition to active state):– MS-initiated PDP context activation– network-requested PDP context
activation
Session Management: States of PDP Context
UMTS Networks 46Andreas Mitschele-Thiel 6-Apr-06
Active state:– valid routing or mapping
information to process data relatedto PDP address (MS, SGSN, GGSN)
– requires PMM state PMM-idle or PMM-connected
-> data transfer possible-> updates due to location changes
PDP context deactivation:– PDP context deactivation procedure– MM state changes to PMM-
detached
PDP context modification, e.g. to modify QoS profile
Deactivate PDP Context or MM state change to IDLE
or PMM-DETACHED
Activate PDP Context
PDP ContextINACTIVE
PDP ContextACTIVE
Session Management: States of PDP Context
UMTS Networks 47Andreas Mitschele-Thiel 6-Apr-06
Session Management: PDP Context and MM
Relation between MM and PDP states:
• All PDP contexts of a subscriber are associated with the same MM context for the IMSI of that subscriber
• The MM state is independent of the number and state of PDP contexts for the subscriber
• In both the PMM-IDLE and the PMM-CONNECTED states, session management may or may not have activated a PDP context
GPRS subscription
PDPaddress
PDPcontext
PDP stateinactive
PDP stateactive
PDPcontext
PDPcontext
PDPcontext
SingleMM context
UMTS Networks 48Andreas Mitschele-Thiel 6-Apr-06
LA
Location-related AreasLocation Area (LA)– area in which a mobile
station may move freely without updating the VLR
Routing Area (RA)– area in which a mobile
station, in PS mode, may move freely without updating the SGSN
– a RA is always contained within a location area
RA
RA
RA RA
RA
RA RA
RA
RA
LA/RAUpdate
RAUpdate
RAUpdate
RAUpdate
LA/RAUpdate
Source: 3GPP 23.002-5.5.0
UMTS Networks 49Andreas Mitschele-Thiel 6-Apr-06
UTRAN Registration Area – URA
LA
RA
RA
RA RA
RA
RA RA
RA
RA
URA
URAURA
URA URA
URA
URAURA
URA URA
URA
URAURA
URA URA
URA
URAURA
URA URA
URA
URAURA
URA URA
URA
URAURA
URA URA
URA
URAURA
URA URA
URA
URAURA
URA URA
URA
URAURA
URA URA
• URA is known to theUTRAN only
• URA is established in RRC connected mode
• URAs may overlap
URA
URAURA U
RA
URA
URA
URA
URA
URA
URA
URA
UMTS Networks 50Andreas Mitschele-Thiel 6-Apr-06
hours
seconds
Resource Management for Packet Data
cell_DCH
URA_PCH
cell_FACH
idle
fast release slow release
UMTS Networks 51Andreas Mitschele-Thiel 6-Apr-06
RRC States and Resource Consumption
cell_DCH
URA_PCH
cell_FACH
idle
T3
T2
T1
• no resource usage
• radio resources• channel codes• HW resources
• signaling resources
• RRC state machine exists as two peer entities, one in the MS and one in UTRAN (SRNC)
• Apart from transient situations and error cases the two peer entities are synchronized
UMTS Networks 52Andreas Mitschele-Thiel 6-Apr-06
Selection of Timeouts – Tradeoffs
cell_DCH
URA_PCH
cell_FACH
idle
T3
T2
T1
fast release
slow release
+ small fixed cost– lots of transitions– call setup delay
– large fixed cost+ few transitions+ small mean call
setup delay
Optimal timeouts depend on traffic model (duration of pauses, traffic mix, mobility)available resources (radio, code, HW)call setup reqs.
UMTS Networks 53Andreas Mitschele-Thiel 6-Apr-06
ReferencesBooks:• Kaaranen, Ahtiainen, Laitinen, Naghian, Niemi: UMTS Networks –
Architecture, Mobility and Services. Wiley 2001• Walke, Althoff, Seidenberg: UMTS – Ein Kurs. J. Schlembach Fachverlag,
2001• Holma, Toskala: WCDMA for UMTS. Wiley, second edition, fall 2002
Central 3GPP Documents:• 21.101/21.102/21.103: List of standards for Release 3, 4 and 5,
respectively• 21.905: UMTS vocabulary and abbreviations • 23.002: UMTS network architecture (CN and AN entities) and procedures• 23.060: GPRS architecture• 25.401: UTRAN overview• 25.301: Radio link protocols (UTRA)• 25.931: UTRAN procedures