GPRS/EDGE

OVERVIEW

Course contents• GPRS Background and Evolution

• GSM/GPRS network

• GPRS Architecture

• IP Addressing in GPRS

• GPRS Air Interfaces

• MS types and Coding Schemes

• Mobility Management

• PDP Context Activation Sequence

• GPRS Roaming

• GPRS Charging

• Practical Demonstration of GPRS

GPRS

BACKGROUND AND

EVOLUTION

GPRS BACK GROUND• With Mobile penetration reaching its full potential, GPRS gives Mobile operators competitive edge and optimum use of the infrastructure.

•SMS is a good example of just how hungry users are for data services.

• The main Objective of GPRS is to offer the access to standard data networks, using protocols e.g. TCP/IP and X.25

• Transactions such as Credit Card checks and a variety of telemetric applications benefit from the fast session set-ups.

• GPRS enables efficient use of radio resources by allowing many data users to share the same interface on a statistical basis.•The main benefits of GPRS are that it reserves radio resources only when there is data to be sent

• Mobile users doesn’t have to connect to the network each time he wants to transfer the data, he can stay connected all day.

Evolution from GSM to 3G

The GSM Growth Phases

GSM2G

HSCSD

GPRS2.5G

EDGE

3G

GSM Evolution

GPRS200 KHz carrier115 Kbps peak data rates

EDGE200 KHz carrierData rates up to 384 Kbps8-PSK modulationHigher symbol rate

UMTS5 MHz carrier2 Mbps peak data ratesNew IMT-2000 2 GHz spectrum

GSM200 KHz carrier8 full-rate time slots16 half-rate time slots

GSM GPRS EDGE UMTS

3G2.5G2G

HSCSD

HSCSDCircuit-switched data64 Kbps peak data rates

MAIN ADVANTAGES FOR OPERATORS

• More Revenue :

By providing more than a mobile connection.

Also operator can charge on the basis of type and amount of content accessed.

• Huge Potential Market for Data Sevices :

Mobile Phone and Internet, both are fastest growing technologies and GPRS is the merger of two.

• Fast Roll-out and Continuous Network Expansion :

GPRS is an integral part of GSM.

• GPRS uses excess voice capacity for data :

GPRS Packets are transmitted in short, free periods between busy hour calls.

Free GSM Capacity

0

2

4

6

8

10

12

14

16

1:00 PM 1:15 PM 1:30 PM 1:45 PM

TCH

0

2

4

6

8

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03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

TC

H

GPRS packets can be transmitted in

the short free periods between busy

hour calls

2TRX = 14 Speech TS

2% blocking means

8 Erlang speech traffic

On average 6 TS free !

GPRS Vs GSM1. SUPPORTS BOTH CKT. Only circuit switched. SWITCHED as well as packet switched service.

2. MS Utilizes Automatic No re-transmission is retransmission (ARQ) at provided. data link layer to re-transmit error frames.

3. Multiple time slots can be Single time slot per user. allotted to a single user

4. One time slot can be allotted Single time slot per user. to several users.

5. Charging/ billing more complex Simple time-based billing. (Volume based, Q.O.S. based)

GPRS Vs GSM

* Communications- E-mail, fax, intranet/ internet access.

* Value added services - Information services, games, e-commerce.

* Location-based applications - Navigation, traffic conditions, airline/rail schedule, location finder.

* Vertical applications - Freight delivery, fleet management, sales-force automation

* Location sensitive A user nearing a cinema hall or Advertising - a restaurant receives flashes of advertisement

TYPICAL GPRS SERVICES

GPRS

NETWORK ELEMENTS

GSM NETWORK ELEMENTS

The Main elements of GSM are:

• NSS :•MSC•VLR•HLR (Includes Authentication Center and Equipment Identity Register)

• BSS :•BSC•BTS•Transcoder

• NMS•Fault Management•Configuration Management•Performance Management

• Network Element Software Hardware• SGSN SG1 DX Platform • GGSN G1 IP650• Firewall Checkpoint IP650• Ethernet Switch N/A Cisco Catalyst • DNS HP-UX 11.00 HP 9000 A class• CG HP-UX 10.20 HP K class• Border Gateway BGP4 IP650• DHCP HP-UX 11.00 HP 9000 A class

GPRS Network Elements

GPRS

ARCHITECTURE

GPRS Interface

HLR

Air (Um)

Gb

Gs Gr Gf

Gn

Gn Inter-PLMN

GPRS Backbone

Gp

External packet network

Gi

SGSN

EIR

BSC

MSC/ VLR

SMS- GMSC

Gd

GGSN

GGSN

Signalling and data

Signalling

• Authentication, Authorization

• GTP tunneling to GGSN

• Ciphering & compression

• Mobility Management

• Session Management

• Interaction with HLR, MSC/VLR

• Charging & statistics

• NMS interfaces

SGSN Role

GGSN Role

• Interface to external data networks• Encapsulate in GTP and forwards end user

data to right SGSN• Routes mobile originated packets to right

destination• Filters end user traffic• Collects charging and statistic information

for data network usage

GPRS

AIR INTERFACES

Different GPRS Capacity Types

TRX 1

TRX 2

CCCH TS TS TS TS TS TS TS

TS TS TS TS TS TS TSTS

CircuitSwitchedTerritory

PacketSwitchedTerritory

Territory border moves basedon Circuit Switched traffic load

GPRSCapacity

DedicatedGPRS

Capacity

TS TS

AdditionalGPRS

Capacity

TS TS

GPRS

MS CLASS &

CODING SCEMES

MS Class• CLASS A:

Supports simultaneous attach, simultaneous activation, simultaneous monitor, simultaneous invocation, and simultaneous traffic.

• CLASS B: Simultaneous traffic shall is not supported. The mobile user can make and/or receive calls on either of the two services sequentially but not simultaneously. The selection of the appropriate service is performed automatically

• CLASS C: Supports only non-simultaneous attach. Alternate use only.

• The status of the service which has not been selected is detached, that is, not reachable.

GPRS Channel Coding Schemes

GPRS

MOBILITY MANAGEMENT

Mobility Management State

Idle

Standby

Ready

PacketTX/RXSTANDBY

Timer Expiry

GPRSAttach / Detach

READYTimer Expiry

MS location known to SGSN level.

MS is capable of receiving Point-to-Multipoint data and being paged for Point-to-Point data

MS location not known.

Subscriber is notreachable by the GPRS NW.

MS location known to cell level.

MS is transmitting or has just been transmitting. MS is capable of receiving Point-to-Point data and Point-to-Multipoint data.

Routing Area

RAI = MCC+MNC+LAC+RAC

GPRS Mobility Management

Routing Area :

The RA is a new concept for tracing the MS location.

Cell =< RA =< LA served by one SGSN

RAI = MCC + MNC + LAC + RAC

Every time the MS sees the new RAI is has to initiate the RAupdate procedure.

Mobility Management States :

•The IDLE State is when the MS is not connected.

•The Standby State is when the MS is connected to the GPRS Network

•The Ready State is when the MS is ready to connect to the external IP Network.

Changing between states can be initiated from the MS, from the network and from the timers set.

GPRS Mobility Management

PDP CONTEXT

ACTIVATION

BTS BSC

SGSN

GGSN

Intranet

GPRS Backbone IP Network

SS7

HLR

DNS

• (1) MS sends "Activate PDP Context Request" to SGSN

•Access Point Name•PDP Type (IP)•PDP Address (empty == dynamic)

• Access Point Name = Reference to an external packet data network the user wants to connect to

Internet

APN="Intranet.Ltd.com"

1.

2.

AccessPoint

• (2) SGSN checks against HLR•Access Point Name•Dynamic / static IP address

PDP Context ActivationAccessing the HLR

SECURITY IN GPRS

• Authentication of the subscriber

• IMEI Checking

• User Identity Confidentiality (TMSI in GSM, P-TMSI in GPRS)

• Ciphering of the data traffic between MS and SGSN

• Private IP Addressing in the GPRS backbone.

• Ciphered links and authentication between nodes in the GPRS Backbone.

• Screening of packets coming from the external networks (Firewall).

(P-TMSI is used to derive the Temp Logical Link Identity (TLLI))

GPRS SYSTEM HAS INHERITED THE GSM PH-2 SECURITY FUNCTIONS

ADDITIONAL GPRS SECURITY FEATURES ARE

The Abbreviation

GPRS = General Packet Radio System

EGPRS = GPRS + EDGE modulation

EDGE – Provide 3G services today

• Provide 3G services with existing licenses

• New modulation optimized for wireless data services

• Link adaptation: Take highest possible rate

• Covered by existing GSM licenses

• Same channel structure, network infrastructure, frequency

planning and protocol as today’s GSM

M

SBTS

PUC

BSC MSC/VLR

HLR

SGSN GGSN

Backbone Network

ISP Network

CorporateNetwork

AUC

SMS G/IW MSC

Gb

Gd

Gs

Gn

Gr

Gn

GiEDGE TRU

M

S

Evolution to EDGE

voice voice voice voice voice

voice voicevoicevoice voice Free TS

DataFree TS

Standard GSM Transceiver

EDGE Transceiver

EDGE increases capacity

System upgrade for EDGE

B

S

C

BSC Software Upgrade

R

B

S

EDGE TRU

EDGE enabled RBS

What EDGE would mean to subscribers

• Streaming Applications

• Very high speed downloads

• Corporate Intranet connections

• Quicker MMS

• Video Phone

• Vertical corporate applications – Video

Conference, Remote presentations

Thank You!