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OMQ000001 GPRS Principle

ISSUE 2.0

Internal Use

Internal Use

Internal Use4

GSM Development EvolutionGSM Development Evolution

57.6 kbps

115 kbps

384 kbps

2 Mbps

GSM

HSCSD

GPRS

EDGE

IMT-2000

9.6 kbps

2G

2.5G

3G

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General Packet Radio Service (GPRS)

is a packet oriented Mobile Data Service available to users of Global System for Mobile Communications (GSM) and IS-136 mobile phones.

It provides data rates from 56 up to 114 k.bit /s.

GPRS is a technology which is changing the present shape of mobile communication.

2G cellular systems combined with GPRS are often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony

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Technology of GPRSTechnology of GPRS

Splits data into Internet Protocol (IP) packets Transmitted in packet switching connection Objectives:

give support for bursty traffic use efficiently network and radio resources provide flexible services at relatively low costs possibility for connectivity to the Internet provide fast access time to have and support flexible co-existence with

GSM voice 

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What is GPRS?What is GPRS?

Bandwidth

share the same bandwidth

be served from a single cell

LIMITED IN REALITY

Speed

Theoretically, maximum speed ~ 144 kbps

Using all eight timeslots at the same time

SPEEDS MUCH LOWER IN REALITY

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Features of GPRSFeatures of GPRS

Key user features of GPRS

IMMEDIACY NEW APPLICATIONS,

BETTER APPLICATIONS

SERVICE ACCESS

Keynetwork features of GPRS

PACKET SWITCHING

SPECTRUM EFFICIENCY

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How is GPRS?How is GPRS?

Technology used by GPRSPacket-mode technique over GSM radio

networksOptimizes the use of radio and network

resources

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When is GPRS?When is GPRS?

Figure: GSM migration paths

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OpportunitiesOpportunities

Bridge of the gap for 3GSensible steeping-stone adoptionTest of higher bandwidth services to come

in 3GFirst time non-voice services to mass

market

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Which is GPRS?Which is GPRS?

Application VOICE MAIL SERVICES CHAT TEXTUAL AND VISUAL INFORMATION IMAGES WEB BROWSING DOCUMENT SHARING/ COLLABORATIVE

WORKING

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Which is GPRS?Which is GPRS?

Applications AUDIO CORPORATE EMAIL INTERNET EMAIL VEHICLE POSITIONING REMOTE LAN ACCESS FILE TRANSFER HOME AUTOMATION

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ApplicationsApplications

Personal Digital Assistant (PDA)

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Advanced Consumer Advanced Consumer ApplicationsApplications information on demand regarding weather,

traffic, entertainment, stock exchange, flight schedule etc.

bank transactions fast communication with the service

provider to receive administrative information such as statements, bill reminders, or new services

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Advanced Business Advanced Business ApplicationsApplications tracking of taxis and credit card validation for

customer payment control over the position of trucks for

transportation companies localization of stolen cars support of security and monitoring systems distribution of specific short messages to

selected groups of users in large corporations

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GSM ArchitectureGSM Architecture

BTSMS

BTS

BTS

MS

BSC

BSC

MSC

GMSC

MS

EIR

VLR

HLR

AUC

PSTNPDN

ISDN

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GPRS ArchitectureGPRS Architecture

BTS

BTSMS

BSC Gb

SGSN

Gf

GsGr

DEIR

MSC/VLR

HLR

Gc

Gn

GGSNGi

PDN

Gp GGSN

Other GPRS

PLMN

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Network interface types Network interface types

GPRS backbone network

SGSNSGSN

SGSNSGSNGGSNGGSNGn

IP interface

SS7 interface

BSS MSCSMS-GMSC

AUm

PDP network (IP/X.25)

Gi

TE

MT

MS

HLR

Gs

Gr

Gd

Gc

Gb

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Key Elements Of GPRS NetworkKey Elements Of GPRS Network

SGSN- Serving GPRS Support Node

GGSN- Gateway GPRS support Node

PCU Packet Control Unit

ADDITIONAL ELEMENTS OF THE GPRS CG ( Charging Gateway)

NMS ( Network Management Center)

BG (Border Gateway)

LIG (Legal Interception Gateway)

DNS

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BSS GPRS MODIFICATIONBSS GPRS MODIFICATION

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BTS Requires Software up gradation

Inclusion of CCU in the BTS

BSC requires software upgrade and addition of PCUSN

PCUSN can contain PCUs

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Packet Control Unit (PCU) Functions Packet Control Unit (PCU) Functions

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Provides physical and logical data interface out of the BSS for

packet data traffic

ARQ functions

Radio channel management

LLC layer PDU segmentation/reassembly

Packet data transfer scheduling

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CHANNEL CODING UNITCHANNEL CODING UNIT

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Channel Coding functions

FEC

Interleaving

Radio channel functions

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Position of PCUPosition of PCU

CCU

CCU

CCU=Channel Codec UnitPCU= Packet Control Unit

CCUPCU

BTS BSC GSN

AGb

Um

CCU

CCUPCU

BTS BSC GSN

B

CCUPCU

BTS BSC GSN

C

Abis

Gb

Gb

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Position of Huawei PCUPosition of Huawei PCU

CCU

CCU

BSCBTS

SGSN

Um

Abis

GbBSC

Pb

CCU

CCU

PCU

BTS

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GPRS(BSS side) upgrade to EDGEGPRS(BSS side) upgrade to EDGE

Upgrade BSC software

Upgrade PCU software

upgrade BTS software

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GPRS shares GSM database resources

Databases software upgrades required to accommodate new GPRS

functionality and parameters when interacting with GSM.

EIR/AuC will also require software upgrades for GPRS-specific

authentication/authorization

DATA BASES-VLR/HLRDATA BASES-VLR/HLR

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SGSN “ Packet Switching MSC – delivers packets to and received

packets from MTs

SGSN sends queries to HLR to obtain profile data of GPRS

subscribers.

An SGSN detects new GPRS in its service area, process registration

and authentication and manages ciphering between MTs and SGSN.

It also performs Mobility Management Functions i.e. GPRS location

Area (LA), attach and detach.

Serving GPRS Support Node SGSNServing GPRS Support Node SGSN

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Interface between GPRS back bone and external PDNs such as

the IP-based internet and X.25 networks.

The GGSN also translate between data formats , signaling

protocols and address information between the GPRS network

and differing external networks.

Address Mapping by using DNS

Supports multiple SGSNs

GGSNs maintain routing information

Gate Way GPRS Support Node (GGSN)Gate Way GPRS Support Node (GGSN)

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GPRS Coding SchemesGPRS Coding Schemes

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CS-1

CS-2

CS-3

CS-4

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Functions of CGFunctions of CG

Real-time collection of GPRS bills

Temporary storage and buffering of GPRS bills

Pre-processing of GPRS bills

Sending GPRS bills to the billing center

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Functions of BGFunctions of BG

BG enables the following protocols necessary for interworking

between operators

Security protocol: IPSec and firewall are recommended

Routing protocol: BGP is recommended

Billing protocol: determined by the operators with negotiation; BG

might be needed in collecting billing information

It is normally based on routers

It can be configured in combination with GGSN

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Functions of MSC/VLRFunctions of MSC/VLR

When Gs interface is installed, MSC/VLR can support Establishment and maintenance of the association between

SGSN and MSC/VLR.

GPRS combined mobility management procedure.

Combined IMSI/GPRS attachment/detachment.

Combined location area/routing area updating.

Circuit paging coordination function.

The wireless resource usage can be greatly improved.

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Functions of HLR/AUCFunctions of HLR/AUC

Saving and updating GPRS subscriber subscription data

User authentication

Providing location/routing information and processing needed

in mobility management and routing, for example:

Saving and updating user service SGSN number and address

GPRS user location deletion indication

Whether MS is reachable.

Subscriber tracing (optional)

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Functions of SMS-GMSC/SMS-IWMSCFunctions of SMS-GMSC/SMS-IWMSC

After Gd interface is installed, short messages can be sent via

GPRS, which reduces the occupation on SDCCH and cuts

down the influence on voice services by SMS services.

The operator can select to send SMS via MSC or SGSN.

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EDGEEDGE

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EDGE can also be known as extended version of GPRS therefore it is also called EGPRS.

EDGE is standardized by 3GPP as part of the GSM family, and it is an upgrade that provides more than three-fold increase in both the capacity and performance of GSM/GPRS networks.

introducing sophisticated methods of coding and transmitting data, delivering higher bit-rates per radio channel.

EDGE can be used for any packet switched application, such as an Internet connection. EDGE-delivered data services create a broadband internet-like experience for the mobile phone user.

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High bandwidth data applications such as video services and other multimedia benefit from EGPRS' increased data capacity.

EDGE was deployed on GSM networks beginning in 2003.

EDGE/EGPRS is implemented as a bolt-on enhancement for 2G and 2.5G GSM and GPRS networks, making it easier for existing GSM carriers to upgrade to it

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EDGE: TRANSMISSION TECHNIQUEEDGE: TRANSMISSION TECHNIQUE

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In addition to Gaussian minimum-shift keying (GMSK), EDGE uses higher-order PSK/8 phase shift keying (8PSK) for the upper five of its nine modulation and coding schemes.

EDGE produces a 3-bit word for every change in carrier phase. This effectively triples the gross data rate offered by GSM. EDGE, like GPRS, uses a rate adaptation algorithm that adapts the modulation and coding scheme (MCS) according to the quality of the radio channel, and thus the bit rate and robustness of data transmission. This increases the probability of correct decoding.

EDGE can carry a bandwidth up to 236.8 kbit/s (with end-to-end latency of less than 150 ms) for 4 timeslots (theoretical maximum is 473.6 kbit/s for 8 timeslots) in packet mode. This means it can handle four times as much traffic as standard GPRS.

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EDGE modulation and coding scheme EDGE modulation and coding scheme (MCS)(MCS)

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 Coding and modulation 

scheme (MCS)

 Bit Rate (kbit/s/slot)

 Modulation 

MCS-1 8.80 GMSK

MCS-2 11.2 GMSK

MCS-3 14.8 GMSK

MCS-4 17.6 GMSK

MCS-5 22.4 8-PSK

MCS-6 29.6 8-PSK

MCS-7 44.8 8-PSK

MCS-8 54.4 8-PSK

MCS-9 59.2 8-PSK

EDGE is four times as efficient as GPRS. GPRS uses four coding schemes (CS-1 to 4) while EDGE uses nine Modulation and Coding Schemes (MCS-1 to 9).

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