andrew j wilton director of applied research gsm systems division

GSM Systems Division

Andrew J WiltonDirector of Applied Research


GSM Systems Division AGENDA

Why Packet? GSM/GPRS Architecture

What is EDGE? Deployment Issues

Standards Terminal Classes

GPRS Applications

Agenda



What is EDGE? Deployment Issues Terminal Classes

Standards GPRS Applications

GSM Systems Division Why Packet?

Bursty Services

bit/s

t

WWW browsing exampleMean

• Many user actions are burstye.g. browsing WWW pages

• Internet has variable delays

• PSTN channel not used 100%

WWW pages

Circuit Data Utilisation

CircuitCapacity

33.6k

* 56.6 Kbits/s

Capacity (Mbytes) USED AVAILABLE* % USED

Email 0.99 9.7 10.2(Download)

Email 0.06 3.0 2.0(Browsing)

Web 0.23 4.2 5.5(browsing)

Why Packet

GSM Systems Division Why Permanent Virtual Circuits?

Modem Modem

Email Server

Auth. Server

InternetGSM PSTN

User

Email via GSM Email via GPRS Email Server

GPRS

User

Auth. Server

Internet

Authenticated path to Email server

Virtual GPRS Data Tunnel

INITIAL CALL PROCESS TIME (s)

• GSM Call 4• TrainModem 30• Login and Authenticate 11• Download mail 180

Total 3 min 45s

SUBSEQUENT CALL

• Repeat Above 3 min 45s

Mail Only When ConnectedMail Only When Connected

INITIAL CALL PROCESS TIME (s)

• GPRS Call 4• Login and Authenticate 11• Download mail 180

Total 3 min 15s

SUBSEQUENT CALL

• Not applicable - Virtual Cct 0min 0s

Mail Continuously DownloadedMail Continuously Downloaded

Permanent Virtual Circuits


* lower figure is data only

Saturated Voice Cell- 1 Carrier- 150 subscribers

Upgradeto

Data Saturated Voice Cell+ 15% Subs are Data Users @ 56kbit/s

Penetration GPRS HSCSD

3% 0 5*-12

15% 0 14*-21

New Timeslots Required 1

1 Conditions:Data - 1:10 duty cycle - 15 minute sessions

- 1 session/ 4 hours~ 10 mins worst case delay

Voice - 20mE - 1% blocking

GPRS - the Low Cost Data Upgrade





GPRS Applications

Agenda


GPRS GPRS RegisterRegisterH/VLRH/VLR

MSCMSC

BTSBTS BSCBSC

GMSCGMSC

HLR/AUCGPRS

RegisterMAP

A-bis

PSTPSTNN

‘A’

GSM Architecture


SGSNSGSN

GPRS GPRS RegisterRegisterH/VLRH/VLR

GGSNGGSN

SGSNSGSN

MSCMSC

BTSBTS BSCBSC

GMSCGMSC

Peer Elements

CircuitCircuitSwitchedSwitchedTrafficTraffic

PacketPacketTrafficTraffic

HLR/AUCHLR/AUCGPRSGPRS

RegisterRegister

A-bis

PCUPCUGb

Gi

Gn

MAP

MAP‘A’

GGSNGGSN

PSTPSTNN

Architecture - GSM with GPRS

Public Switched Public Switched Packet NetworkPacket Network


Routeing info

Intranet

HLR

SGSN

External Data DomainMobililty ManagementSession Management- QoS- Security- Attach/Detach

SGSN Internet

Servers

ClientGGSN

MAPSignalling

MAPSignalling(GGSN) (SGSN)

- Routing- Signalling - Resource Mgt.

Client

BSSPCU

BSSPCU

BSSPCU

BSSPCU

BSSPCU

What IS an SGSN/GGSN


RLC–Segmentation/Re-assembly–ARQ

MAC–Multiplexing (different mobiles)–Contention resolution (u/l) - QOS related–Scheduling/queueing (d/l) - QOS related

CCU

BSC GSNBTS

Abis Gb

PCU

RLCMAC Packet

SwitchingGPRS

Function

The Packet Control Unit (PCU)





GPRS Applications

Agenda


• A new modulation Scheme- 8PSK

• 200 KHz Channel spacing- unchanged

• Symbol rate unchanged- 270k symbol/sBUT- 3 bits/symbol

Rate Code RateCS1 9.05kb/s 0.5CS2 13.4kb/s 0.66CS3 15.6kb/s 0.75CS4 21.4kb/s 1.0

GMSK (1 bit/s/symbol)

GPRSGPRS

Rate Code RateMCS5 22.4 kb/s 0.37MCS6 29.6 kb/s 0.49MCS7 44.8 kb/s 0.76MCS8 59.2 kb/s 1.00

8-PSK (3 bit/s/symbol)

GMSK (1 bit/s/symbol)

Rate Code RateMCS1 8.8 kb/s 0.53MCS2 11.2 kb/s 0.66MCS3 14.8 kb/s 0.80MCS4 17.6 kb/s 1.00

EDGE = GMSK + PSK

EDGEEDGE

EDGE - Key AspectsEDGE - Key Aspects

Coding Rates for GPRS & EDGE


• Higher Date Rate Requires

- More RF Bandwidth

- More C/I

• For EDGE additional C/I

- 7 - 10 dB

= 1+log2 )(CB

SI

Shannon’s LawShannon’s Law EDGE Coverage Relative to Speech EDGE Coverage Relative to Speech 1,21,2

0

20

40

60

80

100

8.8 11.2 14.8 17.6 22.4 29.6 44.8 59.2

% Cell Area Covered

Data Rate / Time Slot

1 Interference Limited Case2 Conditions: • Speech Coverage 12dB C/I

• 4/12 Re-use• No SFH• 10 % Block Erasure Rate

EDGE - Coverage vs Data Rate


* Whole Carrier* Whole Carrier 1 4 time Slots1 4 time Slots 2 Interference Ltd2 Interference Ltd

PathPath StandardsStandards DelayDelay EquipmentEquipment SpectrumSpectrum B/WB/W CoverageCoverage 2

HSCSD 1

GPRS 1

EDGE 1

UMTS*

x4

x4

x20

x40

GSM Now

Now

Q1 ‘99

Q1 ‘00

Q1 ‘00

Evolution Paths for GSM





GPRS Applications

Agenda


• Assumes 4/12 reuse and speech coverage at 12 dB C/I (no SFH)

No Retransmission

0

20

40

60

80

100

8.8 11.2 14.8 17.6 22.4 29.6 44.8 59.2(kb/s)

Two Retransmissions

One Retransmission

Effect of ARQ


• Over Dimension Transmission Over Dimension Transmission - delay budget- delay budget

• QoS ManagementQoS Management

PSTN PPDN

MSCMSC

XCDRXCDR

GGSNGGSN

SGSNSGSN

GMSCGMSC

• TransmissionTransmission• MSC CostsMSC Costs• TranscodersTranscoders

• TransmissionTransmission• IP RoutersIP Routers• Media GatewaysMedia Gateways

? ?

Voice over Packet

Voice over Circuit

BTSBTS

BSCBSC PCU

CostCost Bandwidth vs DelayBandwidth vs Delay

20 ms*

x1

x10

2 ms*

Capacity

Average

bit/s

tVoice

Voice Voice packets packets

lostlost Data in spare voice B/W

Packet Switch

Voice Over IP


GSM SERVICE IMPLEMENTATIONGSM SERVICE IMPLEMENTATION

- MSC based- MSC based- Slow rollout (regression testing)- Slow rollout (regression testing)- Service lost on roaming- Service lost on roaming- New Service introduction- New Service introduction - potentially corrupts all services- potentially corrupts all services- Tied to MSC vendor- Tied to MSC vendor

PSTN PPDN

MSCMSC

XCDRXCDR

GGSNGGSN

SGSNSGSN

GMSCGMSC

BTSBTS

BSCBSC PCU

GPRS SERVICE IMPLEMENTATIONGPRS SERVICE IMPLEMENTATION

- - Client Server basedClient Server based- Very fast rollout- Very fast rollout- Multiple sources for Application - Multiple sources for Application developmentdevelopment- Each service is stand alone- Each service is stand alone - cannot corrupt others- cannot corrupt others- Matched to Web implementation- Matched to Web implementation

IP Address ServerServer

Phone (Client)Phone (Client)

The Service provider


5th Supplier5th Supplier - UMTS RAN- UMTS RAN

BSCBSC PCUPCU

PSTN

MSCMSC

XCDRXCDR

GGSNGGSN

SGSNSGSN

BTSBTS

GMSCGMSC

BSCBSC

XCDRXCDR

BTSBTS

RNCRNC

NODE BNODE B NODE BNODE B

UMTS RANUMTS RAN

IuGb

‘A’

4

22

11

55

33

ServerServerPPDNPPDN Single MSC/Single MSC/

+ BSS Supplier+ BSS Supplier

22ndnd Supplier Supplier- BSS- BSS

33rdrd Supplier Supplier- GPRS Core - GPRS Core NetworkNetwork

44thth Supplier Supplier- Service Framework- Service Framework

GPRS- Opportunities for Competition


UMTS UMTS

GSM

UMTS

• Islands of UMTS coverage- small cell size- demand driven

• Wide area coverage- GPRS or EDGE

• Dual mode UMTS/GSM handsets

ServerServer

GPRS/EDGE

UMTS

UMTS Service

• Services at edge of network- transport via GSM or UMTS

• Service Transparent to Transport- between operators- between media (copper, mobile etc.,)- A few services

- will run less well on GPRS/EDGE

CELLULAR COVERAGE CELLULAR SERVICE

Data

Data

Islands of Coverage


• Client/Server will be the Service Solution

• Opportunities for Competition

• UMTS Ready

• Large number of Application Developers

• Service Re-use on UMTS

• Sell Service on Value not Cost

- Speed of service deployment- UMTS will require for cost effective deployment- No disruption to speech service

- No longer ‘tied’ to switch vendor

- Re-use of GPRS core network

- Competition- Speed

GPRS Threats and Opportunities





GPRS Applications

Agenda

GSM Systems Division Standards Issues

PSTN

MSCMSC

XCDRXCDR

GGSNGGSN

SGSNSGSN

GMSCGMSC

RNCRNC

NODE BNODE B NODE BNODE B

UMTS RANUMTS RAN

Iu InterfaceGb

ServerServerPPDNPPDN

To GSM BSSTo GSM BSS

Upgraded MSCUpgraded MSCNetworkNetwork

GPRS CoreGPRS CoreNetworkNetwork

Iu - One Logical Interface

- Two Physical Interfaces





GPRS Applications

Agenda

GSM Systems Division GPRS Terminal Types

Type A: Can support circuit and packet calls concurrently.

Type B:This type of phone can support circuit or packet (not both together) and can be registered for both…i.e. an IP address and a PSTN number.

Type C:This type of phone can only be registered for packet OR circuit but not both.


Multislotclass

Maximum number of slots Type

Rx Tx1 1 1 12 2 1 13 2 2 14 3 1 15 2 2 16 3 2 17 3 3 18 4 1 19 3 2 1

10 4 2 111 4 3 112 4 4 113 3 3 214 4 4 215 5 5 216 6 6 217 7 7 218 8 8 219 6 2 120 6 3 121 6 4 122 6 4 123 6 6 124 8 2 125 8 3 126 8 4 127 8 4 128 8 6 129 8 8 1

Tx and Rxnotconcurrent

Tx and RxDuplex

Tx and Rxseparateframes

COMPLEXITY FACTOR

Low

Medium

High

GPRS Terminal - Multi-Slot Classes





GPRS Applications

Agenda


• Dual Slot Phones

• SIM Toolkit- some services now

• WAP,MExE- full network interaction- in the future

E-Commerce -Key Enablers

GSM Systems Division E-commerce

Dual-slot mobile phones(SIM Toolkit)

Retailers

Loyalty CardsBankingShoppingPromotions

Financial / Banking

FinanceBankingOn-line transactionsClearing House

Corporate / OperatorApplications

VPNe-mailCost controlIntranet

Certificate Authority

MerchantTransactions

MobileTransactions

Application Providers

ContentNewsWeatherSport

E- Commerce Over GPRS


The End

andrew j wilton director of applied research gsm systems division

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