Mobile Wireless technology

MobileWirelessMobile

Wireless

2N+I_2k © 2000, Peter Tomsu 01_mobile_wirel

Exponential Growth of World Wide GSM Data Users

Exponential Growth of World Wide GSM Data Users

Growth in mobile data is expected to be 70% p.a. in next 5 yrs (Merryl Lynch)

0102030405060708090

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

in m

illion

su

bscri

ber

early adaptors early majority Late majorityinnovators

~ 1%


Dramatic Increase of Mobile Data Volume

Dramatic Increase of Mobile Data Volume

0

5

10

15

20

25

30

35

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Mb

yte

s p

er

user

per

mon

th

UMTS study funded by the European Comission data will account for up to 75% of total mobile traffic by 2005 up to 40% of people in the EU will be using mobile phones

Today0.8 Mb/user/month


Wireless Data Network DriversWireless Data Network Drivers

• Information access

• PDAs

• Network computers

• Alpha paging, information distribution

• Web/WAP technology


DataApplications

Call Forwarding 37%

Paging 33%

Internet/E-mail 24%

Traffic/Weather 15%

Conference Calling 13%

News 3%

Call Forwarding 37%

Paging 33%

Internet/E-mail 24%

Traffic/Weather 15%

Conference Calling 13%

News 3%

Services Most Often RequestedServices Most Often Requested

Source: CTIA Web PagePeter D. Hart Research Associates, March 1997

After Basic Wireless Telephony Service


Data Services on CellularData Services on Cellular

• Standards for packet services on cellular are already defined

GSM: GPRS - GSM Packet Radio SystemGSM: GPRS - GSM Packet Radio System

CDMA: IWF and MobileIPCDMA: IWF and MobileIP

• Both utilize bandwidth over the backhaul/backbone to gateway devices

• A data network built for packet data transport can reduce the need to expand the backbone beyond voice requirements


Wireless Market SegmentsWireless Market Segments

Wireless Market Segments & Partners

Fixed Mobile

Broadband Multiservice2G+

Cellular3G

Cellular

Residential/Premise/ Campus

LMDSMMDS

Cisco/Bosch

DataServices

GPRSMobile IP

PacketData/Voice

UMTS


Residential WLANsResidential WLANs

• Found in office environment for wireless network access

• Either infrared or radio

• Standards are

Bluetooth

IEEE 802.11


Fixed WirelessFixed Wireless

• Provide high speed wireless link to connect remote sites

• Point-to-point or point-to-multipoint

• Line-of-sight or non-line-of-sight systems

• Two standards

LMDS – Local Multipoint Distribution System

MMDS


Mobile Wireless NetworksMobile Wireless Networks

• Usually digital cellular radion networks

• Provide voice and data services

• 1G – analog transmission

• 2G – digital cellular networks (like GSM)

Circuit switched

• 2G+

HSCSD (circuit switched bundeled timeslots)

GPRS (voice CS, data PS)

• 3G – like UMTS

Completely packet switched voice and data


GPRS and other Mobile Wireless Technologies

GPRS and other Mobile Wireless Technologies

GSM dataGSM data Circuit 9.6 kbits/sCircuit 9.6 kbits/s LowLow ETSIETSI Now Now

HSCSDHSCSD Circuit 56 kbits/sCircuit 56 kbits/s MediumMedium ETSIETSI 19991999--20002000

EDGEEDGE Packet 380 kbits/sPacket 380 kbits/s MediumMedium Ericsson Ericsson 2000-20012000-2001

GPRSGPRS Packet 150 kbits/sPacket 150 kbits/s MediumMedium ETSIETSI 2000-20012000-2001

UMTSUMTS Packet 2 Mbits/sPacket 2 Mbits/s High (radio)High (radio) ETSIETSI 20022002

HSCSDHSCSD …… High Speed Circuit Switched DataHigh Speed Circuit Switched DataEDGE EDGE … … Enhanced Data Rate for GSM EvolutionEnhanced Data Rate for GSM EvolutionGPRS GPRS … … General Packet Radio ServiceGeneral Packet Radio ServiceUMTS UMTS … … Universal Mobile Telephone ServiceUniversal Mobile Telephone Service

Technology Type Throughput Investment Std. Body AvailabilityTechnology Type Throughput Investment Std. Body Availability


GSM Packet Data Service OptionsGSM Packet Data Service Options

• Two services as part of "Phase 2+" of the GSM specification

High Speed Circuit Switched Data High Speed Circuit Switched Data

(HSCSD) (HSCSD)

General Packet Radio ServiceGeneral Packet Radio Service

(GPRS)(GPRS)


High Speed Circuit Switched Data (HSCSD)

High Speed Circuit Switched Data (HSCSD)

• allows the combination of multiple timeslots

• Channels can be multiplexed together to offer a data rate of up to 56 Kbit/s when using all four slots (14.4 Kbs/channel)

• because each time slot could carry a conventional conversation, the use of multiple slots restricts the capacity for speech traffic, resulting in the handset user specifying a minimum acceptable data rate and a preferred (and usually higher) data rate

• will prove particularly useful for applications with high-speed data requirements, such as large-scale file transfers, advanced fax services and mobile video communications


General Packet Radio Service (GPRS)

General Packet Radio Service (GPRS)

• available over GSM networks

• Data is packet switched - voice remains circuit switched

• may also be supported as part of other standards, such as DECT and TDMA

• based on the transportation and routing of packetized data

• Capacity limitation is hence in terms of the amount of data being transmitted rather than the time of connection

• reduces the time spent setting up and taking down connections

• works with public data networks using Internet protocol & X.25

• "bursty" applications such as e-mail, traffic telematics, telemetry, broadcast services, and Web browsing

• requires modifications to the GSM system architecture and has targeted commercial availability in the 1999 timeframe


HSCSD vs GPRSHSCSD vs GPRS

• HSCSD is a small market

• HSCD doesn’t do anything to ease spectrum capacity constraints that operators are facing

• GPRS benefits

ultimately, higher speed data

the packet data element is most important because it uses the spectrum in a better way

not tying up a whole channel end-to-end for one user


Enhanced Data Rate for GSM Evolution (EDGE)

Enhanced Data Rate for GSM Evolution (EDGE)

•GSM Standard bodies are defining data networking technologies which will build upon GPRS

•One such technology is Enhanced Data Rate for GSM Evolution (EDGE)

•EDGE will offer a theroretical rate of up to 384 Kbs.

•Beyond EDGE, 3G (UMTS) cellular systems will eventually offer data rates up to 2 Mbs


Universal Mobile Telephone Service UMTS

Universal Mobile Telephone Service UMTS

• 3G mobile system

• Developed within ITU-2000 framework

• Frequency bands

Terrestrial: 1885 – 2025 MHz and 2110 – 2200 MHz

Sattelite: 1980 – 2010 MHz and 2170 – 2200 MHz

• Data rates up to 2Mbps

• Inherent IP support

• Fully packet switched (data and voice)

• Concept of VME (Virtual Home Environment)


GSM Cellular Packet DataGSM Cellular Packet Data

BSCBSC

BSCBSC

MSCMSC

MSCMSC

EIREIR

AUCAUC

HLRHLR

VLRVLRGPRS SGSN and

GGSN provide packet data services

BTS

BTS

Backhaul

Internet

SGSNSGSN

GGSNGGSN

TransitNet

TransitNet

SSS

SSS … Switching SubsystemVLR … Visitor Location RegisterHLR … Home Location RegisterAUC … Authentication CenterEIR … Equipment Identity CenterMSC … Mobile Switching Center

BSS

BSS … Base Station SubsystemBSC … Base Station ControllerBTS … Base Transceiver Stations

GSN … GPRS Support NodeSGSN … Serving GSNGGSN … Gateway GSN


GSM Network AreasGSM Network Areas

BSCBSC

BS

BS

BS

MSC

HLR

EIR

VLR

Switching Subsystem

MSC Service Area

Location Area

Cell

AUC

Base StationSubsystem

Service Area 1

Service Area 2

Service Area n

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS


GSM Network AreasGSM Network Areas

• GSM network consists of geographical areas

Location Areas – LA

made up of a group of cells served by a BSC

BSC hndles inter cell signaling updates

Keeps track of the cell a user is located

MSC/VLR Service Areas

MSC administers several BSCs

handles signaling traffic of inter LA updates

Public Land Mobile Networks – PLMNs

BSCBSC

BS

BS

BS

MSC

HLR

EIR

VLR

Switching Subsystem

MSC Service Area

Location Area

Cell

AUC

Base StationSubsystem

Service Area 1

Service Area 2

Service Area n

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS


GPRS Logical ArchitectureGPRS Logical Architecture

• PS GPRS uses completely different network architecture as underlying GSM network

• Thus introduction of two new network nodes GPRS Support Nodes

SGSN … Serving GSN (GPRS Support Node)

GGSN … Gateway GSN (GPRS Support Node)

Gf

D

Gi

Gn

Gb

Gc

CE

Gp

Gs

Signalling and Data Transfer Interface

Signalling Interface

MSC/VLR

TE MT BSS TEPDN

R Um

GrA

HLR

Other PLMN

SGSN

GGSN

Gd

SM-SCSMS-GMSC

SMS-IWMSC

GGSN

EIR

SGSN

Gn


SGSN and GGSN FunctionalitySGSN and GGSN Functionality

• SGSN

Keeps track of user’s location

Performs security functions and access control

• GGSN

Provides internetworking functions with external networks

Simply a strong router with IP and X.25 capability

Gf

D

Gi

Gn

Gb

Gc

CE

Gp

Gs



MSC/VLR

TE MT BSS TEPDN

R Um

GrA

HLR

Other PLMN

SGSN

GGSN

Gd

SM-SCSMS-GMSC

SMS-IWMSC

GGSN

EIR

SGSN

GnGf

D

Gi

Gn

Gb

Gc

CE

Gp

Gs



MSC/VLR

TE MT BSS TEPDN

R Um

GrA

HLR

Other PLMN

SGSN

GGSN

Gd

SM-SCSMS-GMSC

SMS-IWMSC

GGSN

EIR

SGSN

Gn


Further Elements and EnhancementsFurther Elements and Enhancements

• SGSNs are connected to PCUs (Packet Control Units which are part of the BSC)

Via Gb interface – with FR links

• GSNs are interconnected over Gn interface via IP backbone

GPRS backbone or GPRS network

• HLR is enhanced with GPRS subscriber information

• SMS components are upgraded to support SMS transmission via SGSN

Gf

D

Gi

Gn

Gb

Gc

CE

Gp

Gs



MSC/VLR

TE MT BSS TEPDN

R Um

GrA

HLR

Other PLMN

SGSN

GGSN

Gd

SM-SCSMS-GMSC

SMS-IWMSC

GGSN

EIR

SGSN

GnGf

D

Gi

Gn

Gb

Gc

CE

Gp

Gs



MSC/VLR

TE MT BSS TEPDN

R Um

GrA

HLR

Other PLMN

SGSN

GGSN

Gd

SM-SCSMS-GMSC

SMS-IWMSC

GGSN

EIR

SGSN

Gn


Intra and Inter PLMN Backbone Networks

Intra and Inter PLMN Backbone Networks

• Gp interface

Connects two independent GPRS networks for message exchange

Message exchange done by BG (router)

• Gi interface

Connection between operator’s GPRS networks and external networks (Internet)

BG

SGSN

BG

SGSN

GGSN GGSN

SGSN

Intra-PLMN BackboneIntra-PLMN Backbone

Gi Gp Gi

PLMN A PLMN B

Packet Data Network

Inter-PLMN Backbone


GPRS Support NodesGPRS Support Nodes

• GSN is main element in GPRS infrastructure

Mobility router

Provides connection

Enables interworking with various data networks

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS

BSCBSC

BS

BS

BS

SGSN

SGSN

GGSN

GGSN

Internet

IntranetISP

SGSN

IP Backbone


GGSNGGSN

• Used to access external data network

• IP router containing all necessary routing info for attached GPRS users

• Routing info used to tunnel PDUs to MS’s current point of attachement (SGSN)

• Allocation of dynamic IP addresses

Either itself or external DHCP server


SGSNSGSN

• Serves MS in terms of packet data services

• SGSN establishes connection via GGSN to requested data network

• Maintains all data structures (contexts) for

Authentication

Routing process

• In case of roaming (SGSN and GGSN in different PLMNs) – interconnected via Gp interface

Provides security and others


PCUPCU

• Located in the BSC

• Acts as an interface to the SGSN

• Distinguishes data and voice

• Sends data over FR via SGSN into GPRS backbone

• Realized in SW or HW


APN APN

• Access Point Name

• Defined by ETSI in order to deal with huge number of IP networks to connect to

• Uniquely identifies the network a user wants to access

• L3 protocols defined are IPv4 and IPv6


Access Point Name (username)

Type (Ipv4, Ipv6, X.25)

Access mode (non/transparent)

DHCP local pool information

Accept network initiate PDP

create request

List of PDP contexts on the

APN

IP for DHCP, RADIUS …

IP for charging gateway

APNAPN

• Contains

Name of foreign NW

Network access mode

• Stored in HLR

• User may select APN by himself from the MS


GPRS ConceptsGPRS Concepts

• APN: targeted network (ISP, intranet)

• PDP context: session id

• 1) reach the SGSN (telecom part)

• 2) reach the GGSN serving the APN (GTP=moving tunnel)

• 3) reach the APN (dedicated link, tunnel)


GPRS PDN Interworking ModelGPRS PDN Interworking Model

• GGSN is access point for internetworking

Seen from outside as normal router

GPRS network seems to be normal IP subnet

Gi

IP

GGSN

GPRS Bearer

IP

L2

L1


GPRS Transmission PlaneGPRS Transmission Plane

Relay

NetworkService

GTP

Application

IP / X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

Relay

L2

L1

IP

L2

L1

IP

GTP

IP / X.25

Um Gb Gn GiMS BSS SGSN GGSN

NetworkService

UDP /TCP

UDP /TCP

Um … radio interfaceUses same PL coding as classical GSMThus no HW changesTE requires up to 8 slots / TDMA frame

GTP … GPRS Tunneling ProtocolSNDCP … Subnetwork Dependent

Convergence ProtocolBSSGP … Base Station System

GPRS Protocol


Gb InterfaceGb Interface

• Link layer is FR

• BSSGP (BSS GPRS) conveys routing and QoS info between BSS and SGSN

• SNDCP encapsulates IP traffic between terminal and SGSN

Multiplexing of L3 connections

Ciphering, segmentation, compression

Relay

NetworkService

GTP

Application

IP / X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

Relay

L2

L1

IP

L2

L1

IP

GTP

IP / X.25


NetworkService

UDP /TCP

UDP /TCP

Relay

NetworkService

GTP

Application

IP / X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

Relay

L2

L1

IP

L2

L1

IP

GTP

IP / X.25


NetworkService

UDP /TCP

UDP /TCP


Gn InterfaceGn Interface

• GTP (ETSI) tunnels IP packets between SGSN and GGSN

One tunnel per active TE

• Runs either over UDP or TCP

Relay

NetworkService

GTP

Application

IP / X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

Relay

L2

L1

IP

L2

L1

IP

GTP

IP / X.25


NetworkService

UDP /TCP

UDP /TCP

Relay

NetworkService

GTP

Application

IP / X.25

SNDCP

LLC

RLC

MAC

GSM RF

SNDCP

LLC

BSSGP

L1bis

RLC

MAC

GSM RF

BSSGP

L1bis

Relay

L2

L1

IP

L2

L1

IP

GTP

IP / X.25


NetworkService

UDP /TCP

UDP /TCP

DATAUDP GTPIP

Port #3386


MSMS

• MS could be

Only GPRS phone

User with NW connection via GPRS to his PC

Gi reference point

GPRS network 1

GPRS network 2

PDNs orother networksTE MT

Gp

UmR reference point

MS


Transparent Internet AccessTransparent Internet Access

• User who wants to get connected to internet

• MS is given an IP address out of the operators address space

Could be statically or dynamically allocated

May be public or private

• Authentication performed by SGSN via HLR

The GGSN is effectively a router

The GPRS network appears to the PDN as another IP subnet


Transparent Internet AccessTransparent Internet Access


Non Transparent AccessNon Transparent Access

• Allows user to select SPs of his choice

• Connection to intranet VPN for email access, intraweb, databases

• Has to request IP address and perform authentication in company network

• Realized by SGSN during PDP context activation via selected APN

• MS sends authentication request

• GGSN requests authentication and IP address from specified server (Radius, DHCP) of customers intranet

• Use of Ipsec and/or L2 tunnel for terminating private IP addresses at GGSN via Internet

L2TP & IPsec TunnelGPRS IP

Backbone

Firewalland NAT

GSM

Internet

Firewalland NAT

Corporate VPN

SGSN

GGSN


Interworking Between GPRS Roaming User’s

Interworking Between GPRS Roaming User’s

BGP (RFC 1771)


QoS on GPRSQoS on GPRS

BSCBSC SGSNSGSN GGSNGGSNFRFR TransitTransitNetNet

IPIPBTSBTS PSTNPSTNH.323H.323GWGW

H.323 client

IP QoS

CRTP

FR CoS

Priotities

IP QoS

CAR

WFQ

CRTP

IP QoS

WFQ

WREDIP QoS

H.323 Gateway


Quality of ServiceQuality of Service

Mapping between GPRS QoS and IP QoS levelsMapping between GPRS QoS and IP QoS levels

Delay Class Precedence Mean-Throughput Resulting “canonical” QoSClass

Best Effort any any Best Effort

1, 2, 3 low any Best Effort

1,2, 3 any Best Effort Best Effort

1,2, 3 normal specified Normal

1,2,3 high specified Premium

• Use of IP CoS mechanisms in GGSN/SGSN and in the Backbone: WRED, WFQ, CAR

• Admission Control (GGSN): traffic Total BW


Backbone IssuesBackbone Issues

• Leverage End-to-End Consistency

• WFQ, WRED, CAR

• MPLS (GGSN as edge router)

• Integrated management


IP Address ManagementIP Address Management

• GGSN can hold (local pool/DHCP):

– Operator’s public IP addresses

– Operator’s private IP addresses (NAT)

– Other’s public IP addresses (local pool)

– Other’s private IP addresses (local pool, dedicated I/F)

• configuration per APN


IP Address ManagementIP Address Management

• GGSN can allocate addresses:

– transparently (local pool using built-in DHCP server/DHCP)

– non-transparently (CHAP/IPCP processing, RADIUS/DHCP requests generation) through IOS built-in RADIUS/DHCP clients

• configuration per APN


GSM to UMTS EvolutionGSM to UMTS Evolution


Evolution TowardsUMTS

Evolution TowardsUMTS

• UMTS Backward compatibility to legacy systems

• Operators will try to use existing infrastructure as long as possible

• Development steps

1) MIP on top of GPRS

2) optimize existing routing mechanisms

3) SGSN and GGSN combined in one node

• In future UMTS will completely integrate PSTN

VSCs will replace all class 4 and class 5 switches

Calls will be routed over IP backbone

Questions ???Questions ???

Documents

Mobile Wireless technology