GPRSSYS ver 2.0

8/6/2019 GPRSSYS ver 2.0

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General Packet Radio Services

GPRS


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GPRS COURSE OUTLINE:

Introduction to GPRS Introduction to TCP/IP

GPRS Architecture

GPRS Air Interface

GPRS Traffic Management

Dimensioning of the GPRS Network Gb Detailed Planning

GPRS Parameters

Multimedia Messaging Services


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INTRODUCTION TO GPRS

CONTENTS:

Definition of GPRS

Relationship between GPRS and GSM

Difference between packet switching and circuit

switching Benefits of GPRS

Evolution of GSM towards 3G

Overview of GPRS network


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WHAT IS GPRS?

A technique for the mobile network to providemore efficient access to data network from

GSM

Technology which permits mobile datacommunication using packet switching techniques


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GPRS vs. GSM

GSM allows circuit switched (CS) data transfer Connection oriented Set-up connection as in modem Subscriber charged according to time connection

TS is held duration of connection

GPRS designed as an extension to digital cellularnetworks

Connectionless packet switched (PS) data service Radio resources shared between CS & PS data

New terminals are required


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Circuit Switchex. PSTN, GSM ISDN

Characteristics constant streams of bit

predictable at deterministic

rate short delay end to end connection

under-utilized resource

Circuit Switchex. PSTN, GSM ISDN

Characteristics constant streams of bit predictable at deterministic

rate short delay end to end connection

under-utilized resource

Application: voicevoice, speechApplication: voicevoice, speech

Packet Switchex. Internet, X.25, Frame Relay,

ATM

Characteristics

piece by piece unpredictable chaotic traffic

unpredictable delay no connection

shared resource

Packet Switchex. Internet, X.25, Frame Relay,ATM

Characteristics piece by piece

unpredictable chaotic traffic

unpredictable delay no connection

shared resource

Application: WWW, FTP, EmailWWW, FTP, EmailApplication: WWW, FTP, EmailWWW, FTP, Email


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Circuit Switched

Packet Switched


CIRCUIT SWITCH vs. PACKET SWITCH


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PSTN

GPRS

BackboneIP Network

Internet

Circuit Switched

Packet Switched

GPRS Core

BSC MSC

GGSN

SGSN

BTS

CIRCUIT SWITCH vs. PACKET SWITCH


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BENEFITS OF GPRS

For User new service

faster session

always connected

better charging method

For Operator resource utilization

more revenue

stay in competition

fast roll-out

smooth path to 3G


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EVOLUTION TO 3G

Circuit Data9.6 Kbit/s

Speech

HSCSD57.6 Kbit/s

GPRS171.2 Kbit/s

EDGE384 Kbit/s

3G2Mbit/s

Pre 1997 1997 1998 1999 2000 2001 2002

Functionality

andCapabilities


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GSM

Voice

InternetCorporate

Intranet

Radio Network AccessPoint

Shared GSM &GPRS

Infrastructure

GPRSInfrastructure

IP World

BSCBSCBTSBTSGPRS Core



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BSS

" GPRS brings packet-switched bearer to GSM "" GPRS brings packet-switched bearer to GSM "

GGS

N

SGSN

Radio AccessNetwork

GPRS CoreNetwork

DataNetwork

GPRS Bearer

Interne

t


GPRS NETWORK OVERVIEW


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SUMMARY Q & A

Differentiate Circuit Switch and Packet Switch

What are the benefits of GPRS?

Give the evolution path from GSM to 3G networks.



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Introduction to GPRS Introduction to TCP/IP

GPRS Architecture

GPRS Air Interface



GPRS Parameters




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CONTENTS

Comparison of Internet Protocol and OSI model

IP Address

Concept of Subnetting

Routing Table

Domain Name System DNS Query

INTRODUCTION TO TCP/IP


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??

??

IPIP

TCP/UDPTCP/UDP

HTTP, SMTP,

SMNP, FTP,

Telnet...

HTTP, SMTP,

SNMP, FTP,

Telnet...

PhysicalPhysical

DatalinkDatalink

NetworkNetwork

TransportTransport

SessionSession

PresentationPresentation

ApplicationApplication

OSI-Model TCP/IP

7.

6.

5.

4.

3.

2.

1.


IP AND OSI MODEL


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10101100 01000100 00000111 00000010

172 68 7 2. . .

128+32+8+4 64+4 4+2+1 2


IP ADDRESS

Dotted Decimal Notation


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192.168.0.0192.168.0.0

255.255.255.0255.255.255.0

192.168.0.1192.168.0.1

11000000.101010000.0000000.0000000011000000.1010100.000000000.00000000

11111111.11111111.11111111.0000000011111111.11111111.11111111.00000000

11000000.10101000.00000000.0000000111000000.10101000.00000000.00000001Address

Netmask

Subnetwork

Decimal Binary


SUBNETTING


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Destination Mask Next hop Interface

192.168.0.0 255.255.255.0 Ethernet 0192.168.1.0 255.255.255.0 Tokenring 0

192.168.2.0 255.255.255.0 192.168.0.5 Ethernet 0

0.0.0.0 0.0.0.0 192.168.1.5 Tokenring 0

192.168.1.0/24192.168.0.0/24

192.168.2.0/24

192.168.0.5/24

192.168.2.1/24 192.168.1.1/24

192.168.1.5/24

Internet

192.168.0.1/24

Router 2

Router 1

Router 3

Ethernet 0Tokenring 0


ROUTING TABLE


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IP addresses are 32-bit integers.

The dotted decimal notation representation is more human friendly.

However, long sequences of numbers are still difficult to remember.

There is a need for a higher level representation i.e. Names

Need also arises to translate back and forth between names and IP adds.

SOLUTION: DNSHierarchical NamespaceDecentralization through delegation (distribution)


DOMAIN NAME SYSTEM


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OFFICIAL INTERNET DOMAINS

com - Commercial organizations

edu - Educational institutes

mil - Military groups

gov - Government institutes

net - Major network support centers

org - Organizations (non-commercial)

int - International organizationsCountry domains e.g. India = in, Japan = jp,

Australia = au, Singapore = sg etc.



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HOST

Root DNS server

.com DNS server

nokia.com DNS server

ntc.nokia.com DNS server

gprs.ntc.nokia.com = 192.168.0.15

Local DNS Server

2.

3.

4.

5.

1. 6.

http://www.gprs.ntc.nokia.com 192.168.0.15

DNS QUERY


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Introduction to GPRS

Introduction to TCP/IP

GPRS Architecture

GPRS Air Interface



GPRS Parameters



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GPRS ARCHITECTURE

CONTENTS

GPRS network elements and their functions

GPRS network interfaces

Principle of GPRS Tunneling

GPRS Protocol Stacks


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BSS

GPRS

Core network

External packet

networks

Value added

services (WAP)

GPRS ARCHITECTURE


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Host155.222.33.55

Corporate subnetwork131.44.15.xxx

GPRS subnetwork155.222.33.xxx

Host

131.44.15.3

Router

Router

LAN

Internet

GPRS ARCHITECTURE


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BTS BSC SGSN = Serving GPRS Support NodeGGSN = Gateway GPRS Support NodeNMS = Network Management SystemBG = Border GatewayCG = Charging GatewayFW = FirewallLIG = Lawful Interception Gateway

NMS

GGSN

GGSN

LIG

DNS

FWInternet

BG

InterPLMNNetwork

SGSNCG

BillingCenter

GPRSBackbone

IntranetRouter

Server

LAN

Corporate

FW

OperatorServices

LAN

GGSN

GPRS ARCHITECTURE


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GPRS MS CLASSES

Class A:

Simultaneous GPRS and conventional GSM operation

Supports simultaneous circuit switched and GPRS datatransfer

Class B:

Can be attached to both GPRS and conventional GSMservices simultaneously

Can listen circuit switched and GPRS pages (via GPRS)

Supports either circuit switched calls or GPRS data transferbut not simultaneous communication

Class C:

Alternatively attached in GPRS or conventional GSMNo simultaneous operation

GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN

ChargingGateway (CG) Internet

Backbonenetwork

(IP based)

Intranet

Fire Wall(FW)

LIG

SGSN

Inter-PLMNnetwork

Domain Name Server(DNS)

Gp

HLR/AuCEIR/SMSC

PSTNNetworkMSC/VLR

IubBTS

BTS

BTS

BSC

BSC

Gb

Gi

Ga

Gn

PAPU

PCU

PCU

GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN


Backbonenetwork

(IP based)

Intranet

Fire Wall(FW)

LIG

SGSN

Inter-PLMNnetwork


Gp

HLR/AuCEIR/SMSC

PSTNNetworkMSC/VLR

IubBTS

BTS

BTS

BSC

BSC

Gb

Gi

Ga

Gn

PA

PU

PCU

PCU

GPRS ARCHITECTURE

GPRS ARCHITECTURE


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GPRS ARCHITECTURE

PCU FUNCTIONS

GPRS radio resource allocation and management

GPRS radio connection establishment andmanagement

Data transfer

Coding Scheme Selection

PCU statistics

GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN


Backbonenetwork

(IP based)

Intranet

Fire Wall(FW)

LIG

Inter-PLMNnetwork


Gp

HLR/AuC

EIR/SMSC

PSTNNetwork

MSC/VLR

IubBTS

BTS

BTS

BSC

BSC

PCU

PCU

Gb

Gi

Ga

Gn

PA

PUSGSN

GPRS ARCHITECTURE

GPRS ARCHITECTURE


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OMU

MCHU

PAPU Subunits

ET Cards

SMMU

GPRS ARCHITECTURE

SERVING GPRS SUPPORT NODE (SGSN)

GPRS ARCHITECTURE


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Mobility management Authentication (PAPU/SMMU) Ciphering & compression (PAPU) Protocol conversion

GTP tunneling to GGSN Interaction with HLR, MSC/VLR Charging & statistics NMS interfaces

SGSN FUNCTIONS

GPRS ARCHITECTURE

GPRS ARCHITECTURE


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PACKET PROCESSING UNIT (PAPU)

Protocol conversion from Gn to Gb interfaces:

mean packet switching capacity of 1.3 Mbit/s

peak packet switching capacity of 3 Mbit/s.

Interfaces:

1 100-BaseT Ethernet connection for Gn

up to 64 x 64 kbit/s Frame Relay links for Gb.

1000 routing areas.

Ciphering and compression functions available in the LLC andSNDCP protocols.

7500 connected subscribers. Collects CDRs and sends to MCHU for transmission to CG.

GPRS ARCHITECTURE

GPRS ARCHITECTURE


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SIGNALLING AND MOBILITY MANAGEMENT UNIT (SMMU)

Signaling Provides CCS7 interfaces to NSS network elements (max

24). Handles MTP, SCCP, TCAP, BSSAP+ and MAP protocols.

SMS forwarding.

Mobility management Visiting GPRS subscriber database can handle a

maximum of 30,000 subscribers. IMSI/GPRS attach detach, LA/RA updates, paging,

authentication, etc.

Storage of 10 triplets per attached subscriber.

GPRS ARCHITECTURE

GPRS ARCHITECTURE


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SGSN CHARGING

Three types of CDRs are generated by the SGSN

S-CDR (Session Management)

M-CDR (Mobility Management)

SMS-CDR (Short Message - MO & MT)

CDRs can be transferred to the CG using GTP protocolor can be saved to a ring file on the MCHU in the SGSN

GPRS ARCHITECTURE

GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN


Backbonenetwork

(IP based)

Intranet

Fire Wall(FW)

LIG

Inter-PLMNnetwork


Gp

HLR/AuC

EIR/SMSC

PSTNNetwork

MSC/VLR

IubBTS

BTS

BTS

BSC

BSC

PCU

PCU

Gb

Gi

Ga

Gn

PAPU

SGSN

GGSN

GPRS ARCHITECTURE

GPRS ARCHITECTURE


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Essentially a router Interfaces to external IP networks GTP tunneling to SGSN

Charging & statistics NMS interfaces

GATEWAY GPRS SUPPORT NODE (GGSN) FUNCTIONS

GPRS ARCHITECTURE


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GPRSBackboneLayers 1 & 2 Network layer

BTS BSC

SGSN

GGSNInternet

GPRSCore

Network

SS7

HLRMSC/VLR

TCP/UDP

IP

APP

L1

L2 PublicData NetworkLayers 1 & 2

Tunnelledpayload Network layer

Transport layer

Transport layer

GPRS tunnel

Application Layer

Server

L1

L2

IP

GTP

USERPAYLOAD

UDP

GGSN FUNCTIONALITY

GPRS ARCHITECTURE


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BTS BSC

SGSN

GGSNInternet

GPRSBackboneIP Network

FW

SS7

HLR

MSC/VLR

GTP tunneling to SGSN Interfaces to external IPnetworks Charging & statistics NMS interfaces

Authentication(triplets/SRES) GTP tunneling to GGSN Ciphering & compression Mobility management Interaction with HLR,

MSC/VLR Charging & statistics NMS interfaces

SGSNSGSN

GGSNGGSN

GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN


Backbonenetwork

(IP based)

Intranet

Fire Wall(FW)

LIG

Inter-PLMNnetwork


Gp

HLR/AuC

EIR/SMSC

PSTNNetwork

MSC/VLR

IubBTS

BTS

BTS

BSC

BSC

PCU

PCU

Gb

Gi

Ga

Gn

PAPU

SGSN

GPRS ARCHITECTURE


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Essentially a router similar to GGSN Provides a secure 'tunnel' for

transferring data on the inter-PLMNbackbone between different operators

Supports protocols like BGP-4

BORDER GATEWAY FUNCTIONS

GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN


Backbonenetwork

(IP based)

Intranet

Fire Wall(FW)

LIG

Inter-PLMNnetwork


Gp

HLR/AuC

EIR/SMSC

PSTNNetwork

MSC/VLR

IubBTS

BTS

BTS

BSC

BSC

PCU

PCU

Gb

Gi

Ga

Gn

PAPU

SGSN

GPRS ARCHITECTURE


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Standard IP device Converts domain names into IPaddresses Based on a hierarchical & distributed

model

DOMAIN NAME SYSTEM (DNS) SERVER

GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN


Backbonenetwork

(IP based)

Intranet

LIG

Inter-PLMNnetwork


Gp

HLR/AuC

EIR/SMSC

PSTNNetwork

MSC/VLR

IubBTS

BTS

BTS

BSC

BSC

PCU

PCU

Gb

Gi

Ga

Gn

PAPU

SGSN

Fire Wall (FW)


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GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN

InternetBackbonenetwork

(IP based)

Intranet

Fire Wall(FW)

LIG

Inter-PLMNnetwork


Gp

HLR/AuCEIR/SMSC

PSTNNetwork

MSC/VLR

IubBTS

BTS

BTS

BSC

BSC

PCU

PCU

Gb

Gi

Ga

Gn

PAPU

SGSN

ChargingGateway (CG)

GPRS ARCHITECTURE


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Collects charging data fromSGSN & GGSN Processes the charging data &

forwards it to the BillingSystem

CHARGING GATEWAY (CG) FUNCTIONS

GPRS ARCHITECTURE


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BorderGateway (BG)

GGSN


Backbonenetwork

(IP based)

Intranet

Fire Wall(FW)

Inter-PLMNnetwork


Gp

HLR/AuCEIR/SMSC

PSTNNetwork

MSC/VLR

IubBTS

BTS

BTS

BSC

BSC

PCU

PCU

Gb

Gi

Ga

Gn

PAPU

SGSN

LIG

GPRS ARCHITECTURE


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Intercepts user data, MM information,subscriber information etc.

Forwards it to Law Enforcement Agency (LEA

LAWFUL INTERCEPTION GATEWAY (LIG) FUNCTIONS

GPRS ARCHITECTURE


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IMPACT OF GPRS SYSTEM RELEASE 1 ONEXISTING GSM NETWORK ELEMENTS

SW Upgrade in

MSC/VLR andHLR (M9)

GPRScapableMS

NMS UpgradeT11.5/12 (SW andSNMP Server)

MSC

ISDN/PSTNNetwork

EIRHLR/AuC

SMSC

BSC

BTS

Um

HW and SW

Upgrade in BSC(S9+PCU)

SWupgradingin BTS(B12/DF5)

GPRS ARCHITECTURE


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GSM UPGRADE FOR GPRS RELEASE 1

Network Element Software HardwareBTS (2nd Gen) B12 No

BTS (Talk/Prime) DF5 No

BTS (MetroSite) CX2 (06/00) No

BSC S9 PCU (for each BCSU)

MSC M9 No

NMS T11.5 Server + Workstation

NMS T12 Upgrade to HW

Support forCS1 & CS2

GPRS ARCHITECTURE


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GGSN REDUNDANCY

Two GGSNs providing the same access point

Both GGSNs defined in the DNS for this access point

DNS gives the GGSN IP address in a round-robin fashion

If one GGSN fails, the other one remains up and provides the service

If no response from GGSN, try the other address

All PDP contexts in the failed GGSN are lost and deleted

Mobile needs to re-establish the context.

GPRS

Core

Network

Intranet

DNS

GGSN 1

GGSN 2

SGSN

GPRS TRAFFIC MANAGEMENT


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CHARGING GATEWAY REDUNDANCY

Redundancy principle is configurable (load sharing, N+1, 2N)

Each GSN has a list of CGs that it uses and one marked as

primary CG

When one CG is out-of-operation or busy, CDR traffic is

directed to another CG.

GPRS ARCHITECTURE


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Billing System DataflowPrimary CDR-flow

Secondary CDR-flow

Charging

Gateway 1

ChargingGateway 2

GGSN

SGSN

OperatorIP backbone

GGSN

SGSN

Primary CG 1

2 CG 2

3

n CG x

Primary CG 1

2 CG 2

3

n CG x

Primary CG 2

2 CG 1

3

n CG x

Primary CG 2

2 CG 1

3

n CG x

GPRS ARCHITECTURE


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NETWORK ELEMENTS SOFTWARE HARDWARESGSN SG1 DX PlatformGGSN G1 IP650/740Firewall Checkpoint IP650/740Ethernet Switch N/A

Cisco CatalystDNS HP-UX 11.00 HP 9000 A classCG HP-UX 10.20 HP K classBorder Gateway BGP4 IP650/740DHCP HP-UX 11.00 HP 9000 A class

GPRS ARCHITECTURE

GPRS NETWORK INTERFACES


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HLR

Air (Um)

GbGb

GsGr Gf

GnGn

GnGnInter-PLMN

GPRSBackbone

GpGp

Externalpacketnetwork

GiGi

SGSN

EIR

BSC

MSC/VLR

SMS-GMSC

Gd

GGSN

BG

Signaling and data

Signaling

GaGa

CGGc

Abis


GPRS ARCHITECTURE


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Gb - SGSN to BSS Gn - between GSNs (GTP) Gr - between SGSN and HLR (MAP) Gs - SGSN to MSC (BSSAP+)

Gi - GGSN to external data networks Gf - SGSN and the EIR (MAP) Gd - SGSN and the GMSC (SMSC) Gp - between GSNs of different PLMNs Ga - between xGSN and CG Gc - GGSN to HLR

GPRS ARCHITECTURE


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Userpacket

User

packetUserpacket Userpacket

SGSN GGSN

The stream of containersforming a tunnel.

User

packet

TUNNELLING

The user packets are transported andencapsulated using the GPRS Tunneling Protocol(GTP) over the GPRS backbone. The backbone isan IP network.

GPRS ARCHITECTURE


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GGSN

GTP

IP IP

IP

SGSNMS

IP

GTPTunnel

backbone data using private IP addresses

user data using 'public' IP addresses

TUNNELLING

GPRS ARCHITECTURE


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User packetTunnel ID:IMSI+NSAPI

THE GTP PACKETIP (+TCP/UDP)

Who is the user& what is thecontext?

xGSN IP-address

To which xGSN?

e.g. a TCP/IP packetcarrying e-mail

TUNNELLING

GPRS ARCHITECTURE


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Gateway GPRS Support Node (GGSN): acts as the interface between the GPRS network and externalnetworks

collects charging data and traffic statistics can allocate IP-addresses for users routes packets coming from external networks towards the correct

SGSN and vice versa

Serving GPRS Support Node (SGSN): converts protocols used in the IP backbone to protocols used in the

BSS and the MS takes care of authentication and mobility management routes data to the relevant GGSN when connection to an external

network is required collects charging data and traffic statistics.

GPRS ARCHITECTURE

GPRS PROTOCOL STACKS


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FrameRelay

GTP

Application

IP/ X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

LLC Relay

L2

L1

IP

L2

L1

IP

GTP

IP / X.25

Um Gb Gn GiMS BSS SGSN GGSN

FrameRelay

SNDCP = Sub Network Dependent Convergence Protocol

(Compression / Reassemble) LLC (Ciphering / Error Correction)

GPRS PROTOCOL STACKS

GPRS ARCHITECTURE


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GPRS PROTOCOL STACKS: SGSN-GGSN, SGSN-SGSN, GGSN-GGSN

Based on IP protocol Same protocol stack as for data transfer

UDP

L2

L1

IPL2

L1

IP

UDP

GnGSN GSN

GTP GTP

GPRS ARCHITECTURE


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PROTOCOL STACKS: SGSN-MS

Same lower layers (SNDCP, LLC, RLC, MAC,BSSGP, FR) is used as in data transmission

FrameRelay

L3MM

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

LLC Relay

Um GbMS BSS SGSN

FrameRelay

L3MM

GPRS ARCHITECTURE


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PROTOCOL STACKS: SGSN-HLR/EIR/AuC

For accessing HLR, AuC, EIR and handling SMSs

SCCP

MTP2

MTP3

MTP2

MTP3

SCCP

Gr

Gd

MAP-F

SGSN HLR/EIR/AuC/

GMSC

TCAP

MAP

TCAP

MAP

L1 L1

GPRS ARCHITECTURE


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PROTOCOL STACKS: SGSN-MSC/VLR

For interworking with GSM services (IMSI attach,Location update, CS paging)

SCCP

MTP2

MTP3

MTP2

MTP3

SCCP

GsSGSN MCS/VLR

BSSAP+ BSSAP+

L1 L1

GPRS ARCHITECTURE


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SUMMARY Q& A

Give one GPRS network element and its functions. Name the GPRS network interfaces.

What is GTP?

Give an example of GPRS protocol.



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Introduction to TCP/IP GPRS Architecture

GPRS Air Interface


Dimensioning of the GPRS Network

Gb Detailed Planning

GPRS Parameters


GPRS AIR INTERFACE


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CONTENTS

Difference between physical and logical channels

GPRS Air Interface logical channels and theirfunctions

Coding Schemes

GPRS timeslot usage

GPRS channel allocation process

GPRS AIR INTERFACE


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Interface between the MS and BSS

Major bottleneck in GPRS performance

Uplink Direction

Downlink Direction

MS

Um

GPRS network

GPRS AIR INTERFACE


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Lowest layer of the GPRS protocol stock Primary function is to provide services for information transferover a physical channel Physical Layer is split into 2 sub-layers

Physical RF layer

Physical Link layer

PHYSICAL LAYER

GPRS AIR INTERFACE


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Modulation of RF signals at the transmitter GMSK for GPRS (1 symbol per bit) 8 PSK for EGPRS (1 symbol per 3 bits)

Demodulation of RF signals at the receiver

PHYSICAL RF LAYER

GPRS AIR INTERFACE


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Framing: Placement of data into burst, frames, radioblocks, etc. Data coding for maximizing the data throughput Detection and correction of errors due to noise in themedium

Procedure for detecting the congestion on the airinterface Procedure for synchronizing MS and network Procedures for monitoring and evaluation of radio linkquality Procedure for cell re-selection Transmitter power control

PHYSICAL LINK LAYER

GPRS AIR INTERFACE


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In GSM, 25MHz spectrum is frequency dividedinto 124 * 200 kHz

Each 200 kHz band is time-divided into 8 timeslots (TS) Each TS is equivalent to aphysical channel in GSM Physical channel vs. Logical channel

It is possible to share a TS among many resources

Logical channel implies partial use of TS bymany sources Each physical channel contains a number of

logical channels Traffic channel vs. Control channel

Data and Voice are carried in traffic channel (TCH) Control signal are sent in common control channels

(CCCH)

WHAT IS A CHANNEL?

GPRS AIR INTERFACE

PHYSICAL CHANNEL


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25 MHz

C1 C2 C3 C124

0 1

TCHBCCH

7

Traffic and Control channel

1st TS of RF carrier in cell is reserved for CCCH

Remaining TS are used for TCH Unused TCH can be used for GPRS

Physical Channel

GPRS AIR INTERFACE

LOGICAL CHANNEL


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GSMFCCH

Frequency CorrectionChannel

SCH

Synchronisation ChannelBCCH

Broadcast Control Channel

GPRSPBCCH

Packet Broadcast ControlChannel

Broadcasts packet dataspecific

System Information messages

MS continuously monitors this

GSM BCCH can also be used

GPRS AIR INTERFACE

LOGICAL CHANNEL


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GSM

PCH

Paging Channel

RACH

Random Access Channel

AGCH

Access Grant Channel

GPRS

PPCH (Packet Paging Channel)Can be used for paging both CS & PS services.

GSM PCH can also be used.

PRACH (Packet Random Access Channel)

Used for uplink channel reservation & to obtain TA.

GSM RACH can also be used.

PAGCH (Packet Access Grant Channel)

Used for resource assignment during packet transferestablishment phase.

GSM AGCH can also be used.

PNCH (Packet Notification Channel)

Downlink only channel used for PTM-M notifications to agroup of MS before PTM-M packet transfer.

Only in GPRS Phase 2.

Dedicated Channels

LOGICAL CHANNEL

GPRS AIR INTERFACE


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GSM

SDCCH

Stand alone dedicated CCH

SACCH

Slow Accociated Control Channel

FACCH

Fast Associated Control Channel

TCH

EFR/FR/HR Traffic Channel

GPRS

PACCH (Packet Associated Control Channel) Bidirectional dedicated channel for transferrin

ack./power control or resource assignment/re-assignment messages.

PDTCH (Packet Data Traffic Channel) Bidirectional. Corresponds to the resource allocated to asingle

MS on one physical channel for user datatransmission.

PTCCH Packet timing advance Control Channel. Uplink dedicated (for transmission of randomaccess

bursts). Downlink common (for transmission of timing

advance information to several MSs).

GPRS AIR INTERFACE

GSM LOGICAL CHANNELS USED IN GPRS


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FCCH (Frequency Correction Channel)Initial synchronization with rough frequency and timing

SCH (Synchronization Channel)Network ID, Cell ID (BSIC), and Frame Number

BCCH (Broadcast Control Channel)System Information Parameters and Neighboring Cell listIndicates whether or not the Packet Switched Traffic is

supported( and, if yes, .the location of the PBCCH)

PCH (Paging Channel)MT Packet Transfer and SMS notification

RACH (Random Access Channel)MO Packet Transfer and SMS

Location Update and Routing Area UpdateCell Update generated by MS

TS 0 TS 1 TS 2 TS 3 (Frame 0) TS 4 TS 5 TS 6 TS 7

TDMA Frame

GPRS AIR INTERFACE


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Radio Block 0

PTCCH

Radio Block 3

Radio Block 4

Radio Block 5

PTCCH

Radio Block 9

Radio Block 10

Radio Block 11

Radio Block 1

Radio Block 2

IDLE

Radio Block 6

Radio Block 7

Radio Block 8

IDLE TS 3 (Frame 51)

1 Radio Block= 4 Frames

= 456 info. bits

PDCH multiframe

= 52 TDMA Frames

52 TDMA frames

GPRS AIR INTERFACE


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B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X

normal

burst

01 2 3 4 5 6 7 01 2 3 4 5 6 7 01 2 3 4 5 6 7 01 2 3 4 5 6 7

Radio Block

114 bits

456 bits

GPRS AIR INTERFACE


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GPRS PHYSICAL CHANNEL

The GPRS Physical Channel is called Packet DataChannel (PDCH).

The mapping of different GPRS logical channel to aPDCH is achieved by using a multi-frame structure.

"The 52 TDMA frameThe 52 TDMA frame" One multi-frame has

12 Radio Block (12 x 4 PDTCHs)

2 idle channels

2 Timing channels (PTCCH)

GPRS AIR INTERFACE


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The Up-link State Flag (USF) is assigned to the MS,telling which Radio Block

the MS can use in the up-link.

In the down-link, there is an identifier called

Temporary Flow Identity (TFI)

B11

GPRS AIR INTERFACE



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B0

B1B2

B3

B4

B5

B6

B7

B8

B9B1

0B1

1

USF=1

USF=3

USF=

2

USF=1:

B0- B4

B3

B2

B1

B0

USF=2:

B5- B9

B9

B8B7

B6

B5

B4

CS-19 05

CS-19 05

CS-2

GPRS AIR INTERFACE

CODING SCHEMES


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9.05Kbps

9.05Kbps

CS-315.6Kbps

CS-3

15.6Kbps CS-4

21.4Kbps

CS-421.4Kbps

CS-213.4Kbps

Bundling of up to8 Physical Channel

Bundling of up to8 Physical Channel

Net transmission rate up to171.2 Kbps (21.4 * 8)

Net transmission rate up to

171.2 Kbps (21.4 * 8)

Data Error Correction

GPRS AIR INTERFACE

CODING SCHEMES AND MULTIPLE TSL


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ChannelCodingScheme

CS1 CS2 CS3 CS4

Single TSLData Rate 9.05 kbps 13.4 kbps 15.6 kbps 21.4 kbps

3 TSL

Data Rate 27.15 kbps 40.2 kbps 46.8 kbps 64.2 kbps

8 TSLData Rate 72.0 kbps 107.2 kbps 124.8 kbps 171.2 kbps

Coding Scheme is dependent on the C/I As the MS approaches the BTS, higher CS is used

GPRS AIR INTERFACE


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Three types of timeslots are defined on the Um interface:

Dedicated TSL : Only used for GPRS traffic, does nothandle CS traffic

Default TSL : By default a GPRS TSL, can bedynamically changed CS if CS load is high

Additional TSL : CS TSL by default, can be dynamically

changed to GPRS if required.

GPRS AIR INTERFACE

GPRS TIMESLOTS


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CCCH TS TS TS TS TS TS TS

TS TS TS TS TS TS TSTSTRX 2

TRX 1

Territory border moves dynamically based on CircuitSwitch traffic load

DedicatedGPRS Capacity

Circuit

SwitchedTerritory

Packet

SwitchedTerritory

GPRS AIR INTERFACE

CHANNEL ALLOCATION


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MS Network

Packet Channel Request (1)

Packet Immediate Assignment + PDCH (2)

Packet Resource Request (4)

Packet Resource Assignment (5)

Data Transfer - PDTCH (3)

Need more?

(Optional)

(Optional)

PRACH or RACH

PAGCH or AGCH

PACCH

PACCH

PDTCH

Mobile Originated Packet Transfer

GPRS AIR INTERFACE

CHANNEL ALLOCATION


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MS in Ready State Network

Packet Resource Assignment (assign DL PDTCH)PACCH orPAGCH orAGCH

Mobile Terminated Packet Transfer

GPRS AIR INTERFACE

SUMMARY Q & A


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How many frames and radio blocks are there in aPDCH multiframe?

How many users can share the same PDCHtimeslot in UL / DL?

Which coding schemes does not use FEC?

Which logical channels can be used for resource

assignment?




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GPRS Architecture

GPRS Air Interface



GbDetailed Planning

GPRS Parameters



CONTENTS


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GPRS Connection Procedures

GPRS Mobility Management

GPRS Attach

Cell Update

Routing Area Update

SGSN MSC/VLR Interaction

GPRS Session Management

PDP Context Activation

PDP Context Deactivation

SMS Data Transfer

Roaming

Charging Process

LOCATION OF SUBSCRIBER RELATED DATA



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Identity

IMSI (SIM, HLR, VLR, SGSN, GGSN)

TMSI (VLR, SGSN)IP address (MS, SGSN, GGSN)

Location

VLR-address (HLR)

Location Area (SGSN, VLR)

Serving SGSN (HLR, VLR)Routing Area (SGSN)

Authentication data

Ki, algorithms (SIM, AC)Triplets (VLR, SGSN)


GPRS CONNECTION PROCEDURES


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GPRS Mobility Management (GMM) -Connection to GPRS network

Procedures that take care of the mobility of the user such as GPRS attach,updates about the location of the mobile & security. The GMM procedures aresimilar to the mobility management procedures for circuit switched users.

Session Management (SM) - Connection to IP network

Procedures that handle the GPRS MS connection management toexternal data networks. The process of assigning an IPaddress for becoming part of the IP- network is known as PDP contextactivation.An MM context must be established between the MS &the SGSN before any SM activities are possible.

GPRS MOBILITY MANAGEMENT STATES

Idl S



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Idle State

Subscriber is not attached to the GPRS networkNo valid MM context of the subscriber e.g. MS switched off

RA-1

VLR-1

HLR

SGSN-1BSC

IMSI 244...VLR

IMSILAISGSN ?

IMSI ?RA ?Cell ?

LA-1


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Standb State




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Standby State

Subscriber is attached to the MM contextLocation tracked at RA level If SGSN receives a packet for the MS, it pages in the RA.

A PDP context must be active.

Activation of PDP context possible. If the MS sends data,it moves to the ready state.

MS can receive paging for CS services (optional)The MS Reachable Timer starts ticking when the MS

enters the Standby state & the MS is detached (IDLEstate) upon its expiry (Implicit detach).

IDLE

IDLE

MS locationnot known.Subscriber is notreachable by theGPRS NW




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orREADY timer expireForce to STANDBY

MM State Model of MS

IDLE

READY

STANDBY

GPRS Attach

PDU transmission

Implicit Detach

orCancel Location

GPRS Attach

PDU reception

GPRS Detachor

Cancel Location

MM State Model of MS in PAPU

IDLE

READY

STANDBY

READY timer expiryor

Force to STANDBYor

Abnormal RLC condition

GPRS Detach

GPRS NW.

MS location known toRouting Area level.MS is capable ofbeing paged forPoint-to-Point data

MS location known tocell level.

MS is transmitting or hasjust been transmitting.

MS is capable of receivingPoint-to-Point data

Mobility Management - GPRS Attach (1)

HLR

SGSN-1



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SGSN-1

BSC

RA-1

LA-1

2a 2b

11

(1) MS requests GPRS attach

(2a) The MS is not known in the PLMN so the SGSN requests

subscriber identity (first time)

(2b) The MS sends its IMSI.

GPRS Attach (2) - Authentication

3a

3b HLR

SGSN-1



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3d

3a

RA-1

SGSN-1

BSC

LA-1

3c

(3a) SGSN requests triplets from HLR

(3b) The AC generates the triplets and hands them to the SGSN

(3c) The SGSN sends an Authentication Request to the MS

(3d) MS sends back the Authentication Response

The SGSN performs the authentication

GPRS Attach (3) - IMEI check

EIR4d



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SGSN-1

RA-1

BSC

LA-1

4a

4b

4c

(4a) SGSN asks for the MS IMEI

(4b) MS sends the IMEI

(4c) SGSN sends a Check IMEI message to the EIR

(4d) EIR replies with a Check IMEI ack that will include the list type

Mobility Management - GPRS Attach (4)

5b

SGSN-1

HLR

5a

5d



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RA-1

BSC

LA-1

5c

6a

6b

(5a) SGSN sends an Update location message to the HLR with the IMSI

(5b) The HLR responds by giving subscriber data to the SGSN

(5c) The SGSN acknowledges that it has received the subscriber data ok

(5d) The HLR ends the transaction with an Update Location acknowledge

(6a) The SGSN accepts the GPRS attach and sends the MS a new P-TMSI

(6b) The MS acknowledges that it has received the new P-TMSI

GPRS MOBILITY MANAGEMENTLocation Management



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Location Management

Location management procedures are a group ofmobility management procedures that are used tohandle the changing of a cell or a routing area

e.g. MS moving from cell to cell while transferring orreceiving packet data

MS moving from one Routing Area to the other inStandby state

Cell Update (Cell Reselection)

SGSN-1



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The MS performs a Cell Update when it changes cell within arouting area

in READY mode. This could be compared to a handover in GSM for CS connections

Cell update halts possible reception or sending of data (data isbuffered in SGSN or lost and has to be resent)

BSC-1

RA-1

Old cell New cell

Routing Area Update

SGSN-1



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When the MS changes cell between the different routing areas,it performs a Routing Area Update.

There are two types of routing area updates, the Intra-SGSN

Routing Area Update and the Inter-SGSNRouting Area Update

SGSN-1

BSC-1

RA-1

Old cell New cell

RA-2

Intra SGSN Routing Area Update (1)

HLR



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SGSN

BSC

LA-1

1New RA

MS is listening to information broadcast by cells

MS decides to select a new cell in a different Routing Area (1) Routing Area Update request message is sent by the MS to the SGSN

GGSN


HLR



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SGSN

BSC

LA-1

New RA

Authentication2a : Triplet2b : SRES

GGSN

2

a 2b


HLR



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(3) SGSN checks that the MS is allowed to attach to the RA & sends theRouting Area Update Accept message that may include a new P-TMSI

SGSN

BSC

LA-1

4

2

New RA

GGSN

3

(4) Routing Area Update Complete message



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PERIODIC ROUTING AREA UPDATE

If an MS stays a long time at the same place, the network has toreceive an indication that the MS is still reachable.

All the MSs attached to the GPRS network will perform a periodicRouting Area Update.

Inter-SGSN Routing Area Update

SGSN-1 SGSN-2



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BSC-1

RA-2

Old cell New cell

RA-3

BSC-2

GPRS TRAFFIC MANAGEMENTInter-SGSN Routing Area Update


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Most complex case is Inter-SGSN Routing Area update

MS sends Routing Area update request to new SGSN

New SGSN asks from old SGSN the context of the MS

New SGSN updates GGSNs

New SGSN updates HLRHLR cancels the context in old SGSN

HLR loads the subscriber data to new SGSN

New SGSN acknowledges to the MS

SGSN & MSC/VLR interaction

The optional Gs interface between SGSN & MSC/VLR enablesmore efficient use of network resources



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Combined GPRS/IMSI Attach and Detach

Combined RA/LA update

Circuit switched paging via GPRS network

Non-GPRS alerts : reporting activity of MS to MSC/VLR Identification procedure : SGSN may interrogate the MS on

behalf of VLR to collect some information (e.g. IMEI)

MM Information procedure : MM information (e.g. local timezone) may be passed to the MS via the SGSN

SESSION MANAGEMENT

PDP CONTEXT ACTIVATION



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Process of assigning an IP address for becoming a part of the IPnetwork

One or more addresses can be assigned to an IMSI (MS).

Contains mapping and routing information for transferring PDUsbetween MS and GGSN.

Information includes: IP address, Access Point Name, QoS, RadioPriority.etc.

Static addresses: address allocated by operator to an MSpermanently and this address is stored in the HLR.

Dynamic addresses: GGSN dynamically allocates and releases

addresses as PDP contexts are activated and deactivated.

PDP Context Tables



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PDP Type

PDP Address

IMSI

NSAPIAPN

SGSN Address

Charging ID

...

PDP Type

PDP Address

NSAPI

APN...

PDP TypePDP AddressIMSINSAPI

APNGGSN AddressCharging ID...

Mobile Station SGSN GGSN

PDP context activationOverview



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SGSN

RA-1

BSC

LA-1

3b GGSN

3a

12

4 1. Activate PDP context request

2. Auth. /IMEI check (optional)

3a. Create PDP context request

3b. Create PDP context response

4. Activate PDP context accept

PDP Context Activation - 1

HLR

1. MS sends "Activate PDP Context Request" to SGSN

Access Point Name

PDP Type (IP)

PDP Address (empty = dynamic)

QoS & other options



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BTS BSC

SGSN

GGSN

Intranet

GPRSCore

Network

SS7

HLR

DNS

Internet

APN="Intranet.Ltd.com"

1

2

AccessPoint

2. SGSN checks Subscription data Access Point NameDynamic / static IP address

PDP Context Activation - 2: Finding the GGSN

3. SGSN gets the GGSN IP address from DNS

APN maps to the GGSN IP address



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BTS BSC

SGSN

GGSN

GPRSCore

Network

DNS

Intranet

Internet

3

4

AccessPoint

4. SGSN sends "Create PDP Context Request" to GGPDP Type (e.g. IP)PDP Address (if empty=> dynamic address)Access Point NameQoS & other options

PDP Context Activation 3 Access Point Selection

Access Point Name refers to theexternal network the subscriberwants to use

Physical/logical interface in



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BTS BSC

SGSN

GGSN

GPRSCore

Network

DNS

Physical/logical interface in

GGSN Access Point configuration in

GGSN defines where to connectthe user

Intranet

Internet

APN="Intranet.Ltd.com"

PDP Context Activation 4 Context Activated

User authenticated OK (non-transparent case)

User dynamic IP address allocated by RADIUSserver, or DHCP server, or GGSN internal pool

5 GGSN d "C t PDP C t t R "



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BTS BSC

SGSN

GGSN

GPRSCore

Network

5. GGSN sends "Create PDP Context Response"back to SGSN

Intranet

Internet

5

6

6. SGSN sends "Activate PDP ContextAccept"

to the MS

SGSN now ready to route user trafficbetween

MS and GGSN

GPRS Attach



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MOBILITY MANAGEMENT PROCEDUREEstablishes a logical link between the MS and the SGSN.

Makes the MS available for SMS over GPRS, paging via SGSN,and notification of incoming GPRS data.

Transmission of user data is not possible

PDP Context Activation

SESSION MANAGEMENT PROCEDURE

IP address is assigned to the MS.

Makes the MS known in the corresponding GGSN.

PDP CONTEXT DEACTIVATION



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The MS or the network can deactivate a PDP context.

Every address can be deactivated separately, but performing a

GPRS Detach will automatically remove all the PDP contexts.

SMS data transfer

a) MSC addressb) SGSN address



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MSC

G-MSC

SGSN

HLR

SMSC

1) SMS

2)4a)

4b) 2). Send routing info. for Short Message(GMSC-HLR)

Send routing info. for Short Message resu(HLR-GMSC)

3b)

3a)

Roaming : Connection options

SGSNSingapore

GPRS



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Backbone

HOME

OperatorGPRS

BGBG

GGSNGGSN

Internet

GGSNGGSN

Embassy

Intranet

Inter-PLMNBackbone

BGBG

Gp

Gp

Gi

Gi

Roaming

Alternatives for data and signalling connectionsbetween operators when roaming (for Gpinterface)



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OPERATOR 2Packetnetwork

MoUoperatedInter-operatorbackbone

OPERATOR 1

OPERATOR 3

OPERATOR 4

OPERATOR 5

PacketnetworkINTERNET

BorderGateway

Firewall

SecureFirewall

DIRECT ROAMING:- OP1 - OP2- OP2 - OP5

- OP1 - OP5- OP5 - OP4- OP1 - OP3

ROAMING VIA TRANSIT NETWORK, e.g.:- OP3 - OP2 via OP1- OP1 - OP4 via OP5

BorderGateway

BorderGateway

BorderGateway

Border

Gateway

BorderGateway

BorderGateway

SecureFirewall

Firewall

Firewall

Firewall

Firewall

Router

Router

Router Router

Router

Router

Router

Roaming case 1

CLEARING

Visitor



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SGSN

GGSNAPN

Operator AIP backbone

GGSNAPN

Operator BIP backbone

Internet

Border Gateway

SGSNCG

CG

CCB CCB

HOME

NETWORKVISITINGNETWORK

CLEARING

Visitor

GPRS TRAFFIC MANAGEMENTRoaming case 2


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SGSN

GGSNAPN

Operator AIP backbone

GGSNAPN

Operator BIP backbone

Internet

Border Gateway

SGSNCG CG

CCB CCB

VISITINGNETWORK

HOME

NETWORK

Context Activation for a Roaming User (0)

DNS

DNSVisited Operator



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SGSNSGSN

HOMEOperator

GPRS

BG

BG

.GPRSDNS

Inter-PLMN

GPRSBackbone

GGSNDNS

HOME


DNS

DNSVisited Operator, Singapore

3



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SGSNSGSN

EmbassyIntranet

SingaporeGPRS

Backbone

HOMEOperator

GPRS

BG

BG

.GPRSDNS

Inter-PLMN

GPRSBackbone

GGSN

GSM OPERATOR, Finland

DNS

HOME

2

1


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DNS

DNSVisited Operator, Singapore



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SGSN

EmbassyIntranet

SingaporeGPRS

Backbone

HOMEOperator

GPRS

BG

BG

.GPRSDNS

Inter-PLMN

GPRSBackbone

GGSN

GSMOPERATOR, Finland

DNS

HOME

DNS

HOME

6

7


DNS

DNS

Visited Operator, Singapore

8



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SGSNSGSN

EmbassyIntranet

SingaporeGPRS

Backbone

HOMEOperator

GPRS

BG

BG

.GPRSDNS

Inter-PLMN

GPRSBackbone

GGSNGGSN


DNS

HOME

9

The Data Flow in a Roaming Case

Visited Operator, Singapore



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SGSN

EmbassyIntranet

SingaporeGPRS

Backbone

HOMEOperator

GPRS

BG

BG

Inter-PLMNBackbone

GGSN


Charging of GPRS services

Billi S t



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SGSN

OperatorIP backbone

GGSNBorder Gateway

Inter operatorIP network Internet

Billing SystemCharging gateway

Nokia GPRS Charging Gateway:

* receives CDRs generated bySGSN and GGSN

* consolidates and merges CDRsto a suitable format for BS

GTP'

GTP'


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SGSN CDR (PDP context data) : S-CDRStart collection:

- PDP context activationStop collection:

PDP conte t deacti ation

S-CDRs

M CDR

GPRS TRAFFIC MANAGEMENTGGSN Charging Functions


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- PDP context deactivationCollected information e.g.

- Traffic volumes uplink/downlink- QoS requested/negotiated- Duration- SGSN & GGSN address- Access Point Name

Mobility Management CDR : M-CDRStart collection:- GPRS activation / Incoming SGSNRA update

Stop collection:- GPRS deactivation / OutgoingSGSN RA update

Collected information- Location changes

CG

M-CDRsSMS-CDRs

Internet

GGSN

OperatorIP backbone

SGSN

MS BTS BSC SGSN GGSN

Attach Request

Channel Req

Immidiate Assignment

Press

G startsblinking

Set up Time



140/198


Attach Request

Attach Accept

Activate PDP Context Request

PDP Context Accept

DATA Transfer

Detach Accept

Detach Rerquest

Create PDP Cntxt Req

Create PDP Cntxt Accpt

G issteady

G is BOX

Antenna

Set-up Time

MS Res Time

GGSN Response Time

MessageSent


SUMMARY Q&A

What are the 2 GPRS connection procedures?

What are the 3 Mobility Management states?


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What are the 3 Mobility Management states?

Give an example of GPRS Mobility ManagementProcedure.

Give an example of GPRS Session ManagementProcedure.

Who can initiate GPRS Detach?




GPRS Architecture


142/198


GPRS Air Interface



GbDetailed Planning

GPRS ParametersMultimedia Messaging Services

CONTENTS

BSC Dimensioning

DIMENSIONING OF GPRS NETWORK


143/198


Gb Link Dimensionning

SGSN Dimensioning

BSC Dimensioning The objective is to define the number of active

PCUs per BSC

Gb Interface Link Dimensioning



144/198


Gb Interface Link Dimensioning The objective is to define the number 64 kbit/s

links required per BSC

SGSN Dimensioning The objective is to define the number of SGSNs

and their configuration level in terms of PAPUs

BSC

PCU

SGSN

Frame Relay

Gb

PAPUBSS GPRS

GPRS DIMENSIONING

Things we need to know before the Gb interfaceplanning:

Estimated subscriber volumeEstimated GPRS traffic



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Estimated subscriber volumeEstimated GPRS trafficEstimated number of TCHs/cell used by GPRS on

averageNumber os BSCs

The figures above are based on Busy Hourestimations

BSC is fully equipped with PCUs (=passive) for

redundancyOne PCU installed in each BCSU (8+ PCUs/BSC)

Certain number of the PCUs is activated according todimensioning criteria

Active PCUs are connected to SGSN over the Gbinterface

BSC Dimensioning

The objective is to define the number of active PCUsper BSC.


Th bj ti i t d fi th b 64kb li k



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The objective is to define the number 64kbps linksrequired per BSC.

SGSN Dimensioning

The objective is to define the number of SGSNs andtheir configuration level in terms of PAPUs.

BSC SGSN

BSS GPRS

Frame Relay

Gb

Dimensioning Criteria for the number of active PCUs:

1 Each BSC in GPRS coverage area has to contain at



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1. Each BSC in GPRS coverage area has to contain atleast one active requirement (minimum requirement)

2. PCU supports up to 256 TCHs in maximum 64 cells

* 64 cells supported, if there are 4 GPRS capable TCHs / cell

* 32 cells supported, if there are 8 GPRS capable TCHs / cell

* 1 cell supported, if there are 256 GPRS capable TCHs / cell( unrealistic )

3. PCU Data processing capacity 2 Mbps

3 BSC (with capacity of 128 TRXs)i i h h i ll fi i

T



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( p y ) Coverage area contains 60 BTS sites, each having 2+2+2 cell/TRX configuration,

2 TCHs/TRX used by GPRS on average Estimated GPRS traffic 15 Mbit/s + 16% Overhead = 17.4

1. Minimum requirement : 3 BSC => 3 PCUs required

2. 4 TCHs/cell used by GPRS => PCU supports 64 cells ( 256/4 )PCUs required : 180 / 64 = 2.8 => 3 PCUs required

3. GPRS traffic : 17.4 Mbit/s / 2 Mbit / s = 8.7 => 9 PCUs required

Take the biggest of the results above,I.e. 9 PCUs required in total

INPUT

CALCUL

ATION

S

R

ESULT


BSC Dimensioning

The objective is to define the number of active PCUsper BSC.


The objective is to define the number 64kbps links


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BSC SGSN

BSS GPRS

Frame Relay

Gb


SGSN Dimensioning

The objective is to define the number of SGSNs andtheir configuration level in terms of PAPUs.


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Gb Link Dimensioning

Dimensioning Rules

Dimensioning criteria for the number of 64 kbit/s links:

1. At least two 64 kbit/s channels per active PCU is



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/ p

recommended (due to bursty nature of data)

2. Dimensioning is based on estimated GPRS traffic

during the Busy Hour, + the estimated overhead

on the Gb interface traffic.

Total number of PCUs in BSCs : 9 PCUs Estimated total GPRS traffic during the BH : 15 Mbit/sT



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Estimated total GPRS traffic during the BH : 15 Mbit/s Overhead correction: +16%

Packet size of 400 bytes assumed15 Mbit/s * 16% = 17.4 Mbit /s

1. Two 64 kbit/s links per PCU ( 9 * 2 ) => 18 links2. GPRS traffic : 17.4 Mbit/s / 64 kbit/s = 271.9 => 272 links

Take the bigger of the results above,i.e. 272 links (a 64 kbit/s) required in total

(equals to 9 E1 PCM links)

INPUT

CALCULA

TION

S

RE

SULT

BSCAbis MSC / SGSN siteMUX T d MSC


Gb TOPOLOGY 1


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BSC

BSC

Gb Interface

FrameRelay

MUX Transcoder MSC

SGSN

Ethernet Switch

GGSN #2

GGSN #12 Mbps PCMAter +Frame Relay

BSCAbis

MSC / SGSN site

Transcoder MSC


Gb TOPOLOGY 2


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BSC

BSC

Gb Interface

FrameRelay

Transcoder MSC

SGSNEthernet Switc

GGSN #2

GGSN #1

Packet Data Network

FR switch

FR switch

BSCAbis MSC / SGSN site

Transcoder MSC


Gb TOPOLOGY 3


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BSC

BSC

Gb Interface

Frame Relay

SGSN

Ethernet Switch

GGSN #2

GGSN #1

2 M PCM Links

BSCAbis MSC / SGSN siteTranscoder MSC


Gb TOPOLOGY 4


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BSC

BSC

Gb Interface

/ MSC

SGSN

Ethernet Switch

GGSN #2

GGSN #1

Voice

2M E1PCM FR


BSC Dimensioning

The objective is to define the number of activePCUs per BSC.


The objective is to define the number 64kbps links


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BSC SGSN

BSS GPRSFrame Relay

Gb


SGSN Dimensioning

The objective is to define the number of SGSNsand their configuration level in terms of PAPUs.

SGSN DIMENSIONING

Data processing capacity of fully equipped SGSN :

h bj i i d fi h b f i



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The objective is to define the number of active PCUs per BSC.


The objective is to define the number 64kbps links requiredper BSC.

SGSN DimensioningThe objective is to define the number of SGSNs and theirconfiguration level in terms of PAPUs.

96-SS7 signaling link interfaces (a 64 kbit/s, 24 in each

SMMU)

12 Mbit/s30 000 subscriber

256 Gb IF (64 kbit/s)SGSN



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4 PAPUs, 1 SMMU

4 PAPUs, 1 SMMU

4 PAPUs, 1 SMMU

4 PAPUs, 1 SMMU24 Mbit/s60 000 subscriber512 Gb IF (64 kbit/s)

36 Mbit/s90 000 subscriber768 Gb IF (64 kbit/s)

48 Mbit/s120 000 subscriber1024 Gb IF (64 kbit/s)

Basic Unit

Extensionunits

Dimensioning Criteria for the number of SGSN :1 Subscriber capacity 120 000 subscribers



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1. Subscriber capacity : 120,000 subscribers

simultaneously

2. Data processing capacity : 48 Mbit/s

3. Capacity of 64 kbit/s Gb interfaces : 1024

Estimated subscriber volume : 80 000 subscribers

( simultaneously attached during the BH ) Estimated total GPRS traffic during the BH : 15 Mbit/s

PUT



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Estimated total GPRS traffic during the BH : 15 Mbit/s with the overhead correction : 17.4 Mbit/s Number of 64 kbit/s Gb links : 272

1. Subscriber capacity : 1 SGSN with Basic Unit + 2 Extension Units

2. Data capacity : 1 SGSN with Basic Unit + 1 Extension Unit3. Gb I/F capacity : 1 SGSN with Basic Unit + 1 Extension Unit

Take the biggest of the results above,

i.e. 1 SGSN with basic Unit + 2 Extension Units required

INP

CALCULA

TION

S

RESUL

T

Gb Interface Traffic Analysis

DATA

LLC

BSGGP

IP

SNDCP

IP

SNDCP

LLC

BSGGP

RFC 791

GSM 04.65

GSM 04.64

GSM 08.18

24

9

30

4

PROTOCOLHEADER

SIZE (oct) REFERENCE

Overheadgeneratedby theprotocol

layerson the Gb

Packet ofVariable size



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BSGGP

NS

FR

BSGGP

NS

FR

TOTAL

GSM 08.18

GSM 08.16

GSM 03.60

30

4

6

77

interface

E.g. 77 oct= 16 %

77 oct + 400 oct

Percentage of overhead in GPRS

traffic on the Gb interface

(as a function of Packet size)

100 200 300 400 500 750 1000 1250 1500

Packet length (octets)

Overhead(%)

50

45403530252015105

0


SUMMARY Q&A

What is the capacity of 1 PCU? What is Gb link?


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What is Gb link?

What is capacity of the SGSN rel. 1?




GPRS Architecture

GPRS Air Interface


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GbDetailed Planning

GPRS Parameters


Gb Transmission Topology


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Gb Transmission Topology


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Gb Detailed Plan Parameters


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Gb Planning Considerations


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Gb Planning Recommendations


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Basic Configuration


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NS-VC Link


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NS-VC Redundancy & Load Sharing


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GPRS Architecture

GPRS Air Interface



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GbDetailed Planning

GPRS Parameters


BSS Parameters

Parameter Name Range Smart Setting

1. Enabling of GPRS

BSC_GPRS_PARAM_ENABLED Y/N Y

GPRS ENABLE (GENA) Y/N YGPRS ENABLED TRX (GTRX) Y/N Y (2 TRX)

2. GPRS Territory


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y

GPRS Territory Update Guard Time (GTUGT) 0255 sec 5 sec

Dedicated GPRS Capacity (CDED) 0100% 1% - entire network

except Makati (2 GPRS

dedicated t imeslots)

Default GPRS Capacity (CDEF) 0100% 24% (cells with >1 TRX)

50% (1 TRX)

Prefer BCCH Frequency GPRS (BFG) Y/N N

3. Power Control

Binary Presentation Alpha (ALPHA) 010 GSM 900: 7

GSM 1800: 8

Binary Presentation Gamma (GAMMA) 010 GSM 900: 34

GSM 1800: 36

Transfer mode signal strength filter period (TFP) 025 13

Idle mode signal strength filter period (IFP) 025 9


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SGSN Parameters

Parameter Name Definition Smart Setting

IMEI check mode (ICHM) defines if IMEI check is performed by

SGSN

OFF


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SGSN

Authentication Mode (AUM) defines if Authentication is

performed by SGSN

ON

PTMSI Signature Mode (PSMO) defines the usage of PTMSI

signature

ON

Ciphering Mode in Use (CIPINUSE) defines if the data between MS andthe network is ciphered

ON

Ciphering Mode after system restarts defines whether ciphering is ON and

OFF after system res tarts

ON

SGSN Parameters

Parameter Name Definition Smart Setting

Ready State Timer (RTY) defines how long the MS and

SGSN MM context remain inready state.

44 seconds

MS Reachable Timer (MSRT) defines the timer for triggering a

t k i i t d d t h f th

60 minutes


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network originated detach for the

subscriber if no interaction with

the network is made.

Periodic RA Update (PRAU) defines the timer for the MS to

trigger periodic routing arae

update.

54 minutes

Force to Standby (FTS) defines whether the SGSN should

command the MS to change its

state to standby after mobility

management procedures.

Y

Detached Subscriber Storage Time defined as the time wherein the

data of the detached subscriber is

stored in the visiting subscriber

database of the SGSN

1 day


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What is MMS?

After SMS, MMS Multimedia Messaging Service, is supposed to be the nextbig thing for mobile phone operators.

Multimedia Messaging Service

T t bi d ith i h t t t


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Text combined with rich content types

Images (JPEG, GIF and Animated GIF)

Voice clips (AMR)

Audio clips (WAV, MIDI)

Video clips (future) (MPEG)

Subscriber addressing based on MSISDN or email address

Services

Person to Person Messaging (MMS to MMS)


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Person to Person Messaging

MMS Subscriber A will sendmultimedia message to MMSSubscriber B

MMS Subscriber A willtake a picture using hismobile phone

MMS SubscriberB receives MMS


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MMS MMS


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Internet

WAPGateway

MMSC

TerminalGateway

MSISDN-A

Press send.Initiate WAP session.



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GSM/GPRS

SMSC

MMS Terminal-B receives WAP PushSMS notification for receipt ofmultimedia message.

MSISDN-B

WAPPush

Retrieving

message

Hello,there!

Sending of multimedia messages to MMS capable phone

Internet

GSM/

WAPGateway

MMSC

TerminalGateway

MSISDN-A



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GSM/GPRS

MMS Terminal-B initiates automatic WAP

session via GPRS to retrieve multimediamessage located in the MMSC.

MSISDN-B

Hello, there!

Fetch msg. Initiate WAP session. SMSC

Hello,there!

Receiving of multimedia messages to MMS capable pho


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Services

Person to Person Messaging (MMS to Legacy)


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MMS Subscriber A will send

multimedia message toLegacy Subscriber B

MMS Subscriber A will take apicture using his mobilephone

Legacy Subscriber Breceives SMS notification



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MMS Legacy

Internet

GSM/

WAPGateway

MMSC

TerminalGateway

MSISDN-A

Hello, there!


Hello



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Sending of multimedia messages to a non-MMS capable

MMS Terminal-A sends multimediamessage to non-MMS Terminal-B.

GSM/GPRS

SMSC

MSISDN-B

Hello,there!

Internet

GSM/

WAPGateway

MMSC

TerminalGateway

MSISDN-A


Hello



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GSM/GPRS

MSISDN-B

SMSC

MMS Terminal-A sends multimediamessage to non-MMS Terminal-B.

Hello,there!


Internet

GSM/

WAPGateway

MMSC

TerminalGateway

MSISDN-A


Hello,



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GSM/GPRS

SMSC

SMSC send to Terminal-B legacy phonethe WAP Push SMS notification forreceipt of multimedia message.

MSISDN-B

WAPPush

Hello,there!


Internet

GSM/

WAPGateway

MMSC

TerminalGateway

MSISDN-A

Hello,



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GSM/GPRS

SMSC

MMS Terminal-B ignored the WAP pushSMS since it doesnt recognize themessage. MMSC retries sending theWAP push SMS and start timer.

MSISDN-B

WAPPush

there!


Internet

GSM/

WAPGateway

MMSC

TerminalGateway

MSISDN-A

Hello,

Hello,there!



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GSM/GPRS

SMSC

MSISDN-B

there!

No response from terminal withinpredefined time, which is set to 10minutes.

MMSC will now assume that theMSISDN-B is a legacy phone. MMSC willsend a copy of the MMS message toTGW.


Internet

GSM/

WAPGateway

MMSC

TerminalGateway

MSISDN-A

Hello,th !

Hello,there!



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GSM/GPRS

SMSC

MSISDN-B

Regular 160-char WAP push SMS

TGW will send SMS to Non-MMS terminalB containing URL, Username, Passwordfor Web retrieval.

MessageID +

Password+

URL

there!


Web Interface Support for Legacy Phone


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Viewing of multimedia messages via the Web

Subscriber will use URL received to go toSMARTs Multimedia Portal.

Using the username and passwordreceived from SMS Push, subscriber canlog-in to the portal.

Subscriber can now read multimediamessages received.

MessageID +

Password+

URL

Hi, there!

Thank You!


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Documents

GPRSSYS ver 2.0