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INTRODUCTION
GPRS stands for General Packet Radio
Service, and is a relatively low cost
technology that offers packet-based
radio service and allows data orinformation to be sent and received
across mobile telephone networks.
Designed to supplement the existingmobile technologies, like GSM, CDMA,
TDMA etc.
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It is a packet oriented mobile data service
It is available to all users having 2G communication system,as well as inthe 3G systems.
In 2G systems, GPRS provides data rates of 56- 114 kbit/second.
GPRS data transfer is typically charged per megabyte of traffic transferred.
2G cellular systems combined with GPRS are often described as 2.5G, thatis, a technology between the second (2G) and third (3G) generations ofmobile telephony.
GPRS is classified as a 2.5G technology because it builds upon existingnetwork infrastructure whereas with 3G networks it normally requires buildingan entirely new network.
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WHAT DOES GPRS DO?
GPRS provides a permanent connectionwhere information can be sent or receivedimmediately as the need arises, subject toradio coverage.
No dial-up modem connection isnecessary. This is why GPRS users are sometimes
referred to be as being anytime-anywhere"always connected".
The GPRS traffic structure is based on afixed cost, dependent on the quantity ofdata required.
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Services offered
"Always on" internet access
Multimedia messaging service (MMS)
Instant messaging
Internet applications for smart devices
through wireless application protocol
(WAP)
Point-to-point (P2P) service: inter-
networking with the Internet (IP)
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GPRS TERMINALS
Class A
MS supports simultaneous operation of GPRS andGSM services
Class A terminal can make or receive calls on twoservices simultaneously
Class B
MS able to register with the n/w for both GPRS &GSM services simultaneously. It can only use one ofthe two services at a given time.
Users can make or receive calls on either a packet ora switched call type sequentially, but notsimultaneously.
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Class C
MS can attach for either GPRS or
GSM services
a Class C terminal can make or
receive calls from only the manually
(or default) selected service
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GPRS ARCHITECTURE
GPRS Subscriber Terminals
GPRS BSS
GPRS Networks Node
GPRS Mobility Management
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GPRS SUBSCIBER TERMINALS
New terminals are required because existingGSM phones do not handle the enhanced airinterface, nor do they have the ability topacketize traffic directly.
A variety of terminals will exist, including ahigh-speed version of current phones tosupport high-speed data access.
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GPRS BSS
Each BSC will require the installation of oneor more PCUs (packet control unit) and asoftware upgrade. The PCU provides aphysical and logical data interface out of thebase station system (BSS) for packet data
traffic. The BTS (base transceiver site) may also
require a software upgrade, but typically willnot require hardware enhancement.
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GPRS NETWORKS NODE
In the core network, the existing MSCs arebased upon circuit-switched central-officetechnology, and they cannot handle packettraffic.
Thus two new components, called GPRSSupport Nodes, are added:
Serving GPRS Support Node (SGSN)
Gateway GPRS Support Node (GGSN)
BACK
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SGSN The SGSN can be viewed as a "packet-
switched MSC;" it delivers packets to mobilestations (MSs) within its service area
SGSN performs mobility managementfunctions such as mobile subscriber
attach/detach and location managementGGSN GGSNs are used as interfaces to external IP
networks such as the public Internet
GGSNs maintain routing information that isnecessary to tunnel the protocol data units(PDUs) to the SGSNs that service particularMSs
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GPRS MOBILITY MANAGEMENT
Mobility management within GPRS builds on the
mechanisms used in GSM networks.
As a MS moves from one area to another,
mobility management functions are used to track
its location within each mobile network.
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OTHER ELEMENTS
BG (Border Gateway) (Not defined within GPRS) Routes packets from SGSN/GGSN of one
operator to a SGSN/GGSN of an otheroperator
Provides protection against intruders fromexternal networks
DNS (Domain Name Server) Translates addresses from ggsn1.oper1.fi -
format to 123.45.67.89 format (i.e. as usedin Internet)
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OTHER ELEMENTS
Charging Gateway
Collects charging information from SGSNsand GGSNs
PTM-SC (Point to Multipoint -ServiceCenter)
PTM Multicast (PTM-M): Downlinkbroadcast; no subscription; no ciphering
PTM Group call (PTM-G): Closed or opengroups; Down/up -link; ciphered
Geographical area limitation
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HOW GPRS WORKS
GPRS provides packet data services (similar to the
Internet) using the GSM digital radio network. Eachvoice circuit in GSM transmits the speech on a secure
14kbps digital radio link between the mobile phone and
a nearby GSM transceiver station.
RADIO INTERFACE
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RADIO INTERFACE
Each transceiver uses TDM to deliver eightvoice circuits on one radio channel
The GPRS service joins together multiplespeech channels to provide higher bandwidth
data connections The radio bandwidth remains the same, it is
just shared between the voice users and thedata users
higher the data rate, the more power the
mobile device will use and the shorter thebattery life and the higher the transmitted RFpower
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GPRS ROAMING
Home Network Roaming - Here alldata is transmitted from wherever you
connect to a GPRS network to your
home GPRS network Local Network Roaming - Data is just
transmitted to a local Internet connection
point and will be subject to localconditions for security and performance.
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GPRS MOBILE DEVICES
The key use for GPRS is to send andreceive data to a computer application
To use GPRS, the service is 'dialed' at
which point the user is 'attached' and an IPaddress is allocated
The three standard methods to connectyour computer to GPRS mobile phone are:
1 Infrared2 Data-cable
3 Bluetooth
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GPRS SECURITY
The radio interface is considered to be
relatively secure being controlled by the GSM
network's security - (SIM card + HLR).
Security issues arise when data needs to
leave the GPRS network to be delivered to
either the Internet or a company LAN.
Internet connectivity is the cheapest andmost common - and here you can take charge
of security by encrypting sensitive data.
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NETWORK CONNECTIVITY
Three ways to connect to GPRS network
1. Internet
2. Leased Lines
3. Frame Relay
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NETWORK
CONNECTIVITY LEASED LINES
Leased lines provide the most securemethod of connecting to GPRS but are
traditionally expensive FRAME RELAY
If a frame relay connection is availablewith network suppliers then adding anaddition PVC (Private Virtual Circuit) toone of the GPRS networks will make acost effective solution
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DATA PACKET ROUTING
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Data Packet Routing
GGSN handles interaction with the external datanetwork.
routes external data packets to the SGSN
Three different routing schemes arepossible:
Mobile-originated message.
Network-initiated messages when the MSis in its home network.
Network-initiated messages when the MS has
roamed to another GPRS operators network.
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Data Packet Routing
GPRS operators will allow roaming through aninter-operator backbone network
GPRS operators connect to the inter-operatornetwork by a border Gateway (BG)
The main benefits of the architecture are itsflexibility, scalablity, interoperability androaming
The GPRS network encapsulates all data
network protocols into its own encapsulationprotocol, called the GPRS Tunning Procotocol(GTP).
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Data Packet Routing
The operation of GPRS is partlyindependent of the GSM network.However, some procedures share the
network elements with current GSMfunctions.
A mobile station has three states in theGPRS system:
Idle Standby
Active
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KEY USER FEATURES OF
GPRS
SpeedTheoretical maximum speeds of up to
171.2 kilobits per second are achievablewith GPRS
ImmediacyGPRS facilitates instant connections
whereby information can be sent orreceived immediately as the need arises
New applications, betterapplications
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KEY NETWORK FEATURES OF
GPRS
Packet SwitchingGPRS involves overlaying a packet based air
interface on the existing circuit switched GSMnetwork With GPRS, the information is split intoseparate but related "packets" before beingtransmitted and reassembled at the receivingend
Spectrum EfficiencyThe available radio resource can be concurrently
shared between several users. This efficient use ofscarce radio resource means that large numbers ofGPRS users can potentially share the samebandwidth and be served from a single cell.
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KEY NETWORK FEATURES OF
GPRS
Internet aware
File Transfer Protocol (FTP), web
browsing, chat, email, telnet- will be as
available over the mobile network
because of GPRS. Hence, web
browsing is a very important application
for GPRS. Supports TDMA and GSM
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THANK YOU