GPRS (General Packet Radio Service) is a standard for wireless communication that improves data transmission for cellular networks. It allows faster data transmission than previous cellular data services. GPRS uses a packet-based transmission method which improves network capacity and efficiency. The core network elements include SGSN (Serving GPRS Support Node) and GGSN (Gateway GPRS Support Node). SGSN manages data transmission to and from mobile stations, while GGSN acts as an interface between the GPRS network and external packet data networks. GPRS supports bandwidth from 5-40kbps and introduces volume-based billing rather than charging by connection time.

1. GPRS
(General Packet Radio Service)
Presented By
P Vishal Narayan
(Reg. no. 19304026)
M. Tech ECE, I year.
Department of Electronics Engineering
Pondicherry University

2. Introduction
 From along time, wireless WANs have promised instant
access to information from anywhere.
 But the reality has been otherwise, existing cellular data
services do not fulfill the needs of users and providers.
 From the user's point of view;
1. Data rates are too slow, Connection speeds that have a
restriction at a maximum rate of 14.4Kbits/sec for most
networks.
2. The connection setup takes too long and complicated.
3. The service is too expensive

3.  From the technical point of view
1. The drawback results from the fact that current
wireless data services are based on circuit switched
radio transmission.
2. A complete traffic channel is allocated for a single
user for the entire call period and this results in a
highly inefficient resource utilization
3. In circuit switched services, billing is based on the
duration of the connection
 Packet switched bearer services result in a much
better utilization of the traffic channels.
1. A channel will only be allocated when needed and released
immediately after the transmission of the packets.
2. With this principle, multiple users can share one physical
channel.

4. What is GPRS?
 New service for GSM that greatly improves and
simplifies wireless access to packet data networks.
 Standardized by ETSI (European Telecommunications
Standards Institute).
 Networks based on the Internet Protocol (IP) and X.25
 Theoretically maximum rate is just 171. 2 Kbits/sec.
 A realistic estimation on transfer is between 5 and 40 kbps.
 It applies a packet radio principle to transfer user data packets in an
efficient way.
 This principle offers a more user-friendly billing than that offered
by circuit switched services.
 User can be "online" over a long period of time but will be billed
based on the transmitted data volume.

5. Main
Elements
GPRSSUPPORT
NODES
GatewayGPRS
SupportNode
GGSN
ServingGPRS
SupportNode
SGSN
GPRSMOBILE
STATIONS
MobileStation
is requiredto
accessGPRS
services
Wheneithervoice
ordatatrafficis
originatedatthe
subscriber
mobile,it is
transportedover
theairinterface
totheBTS
GPRS BASESTATION
SUBSYSTEMS ROUTINGAERA
Routingareais
similarto
LocationArea
inGSM,except
thatit
generally
containsfewer
cells
INTERNAL
BACKBONE
Theinternal
backboneis an
IPbased
networkused
tocarry
packets
between
differentGSNs

6. GPRS
SUPPORT
NODES
ServingGPRSSupport
Node(SGSN)
GatewayGPRSSupport
Node(CGSN)
GPRS Support Nodes

7. SGSN( Serving GPRS Support Node
)
 Routing the packet switched data to and from the mobile
station.
 Mobility management.
 Data management.
 Authentication and charging for cells.
 Stores the location information of the user.

8. GGSN ( Gateway SPRS Support
Node )
 Provides a gateway between GPRS and PDN (Packet Data
Networks).
 Converts data from SGSN to PDP format (Packet Data
Protocol).
 Stores the current SGSN address.
 Stores the location of user in it’s location register.
 Performs authentication and charging functions.

9. GPRS Subsystems
01
02
03
04
Base Station System
(BSS)
Network Sub-system
(NSS)
Gateway Sub-system
(GSS)
Radio Station Sub-
System
(RSS)

10. BASE STATION SYSTEM
(BSS)
● BSS needs enhancement to
recognize and send packet
data
● BSS includes BTS (Base
Transceiver Station) and
MS (Mobile Station)
● It consists of a number of
SGSN (Serving GPRS
Support Node)
● Also consists of a number of
MSC (Mobile-Service
Switching Center)
● Helps in authentication,
operation and maintenance of
subsystems
NETWORK SUB-
SYSTEM (NSS)

11. RADIO STATION SUB-
SYSTEM (RSS)
● Consists of a number of MS
(Mobile Station), BTS (Base
Transceiver Station) and
BSC (Base Station
Controller)
● Stores a CKSN (Cipher Key
Sequence Number - a
logical identity)
● Consists of SGSN
(Serving GPRS Support
Node) and GGSN
(Gateway GPRS Support
Node)
● Provides connections
to other networks
and PDA (Public Data
Network)
GATEWAY SUB-SYSTEM
(GSS)

12. GPRS Architecture

13.  A serving GPRS support node (SGSN) is responsible for
1. Delivery of data packets from and to the mobile stations
within its service area.
2. Packet routing and transfer Mobility management
(attach/detach and location management)
3. Authentication and charging functions. The location register
of the SGSN stores location information and user profiles (IMSI,
addresses used in the packet data network) of all GPRS users registered
with this SGSN.
 A gateway GPRS support node (GGSN) acts as an interface between
the GPRS backbone network and the external packet data networks.
1. It converts the GPRS packets coming from the SGSN into the
appropriate packet data protocol (PDP) format (IP or X.25) and sends
them out on the corresponding packet data network.
Architecture…

14. 2. In the other direction, PDP addresses of incoming
data packets are converted to the GSM address of the
destination user. The readdressed packets are sent to the
responsible SGSN. For this purpose, the GGSN stores the
current SGSN address of the user and his or her profile in its
location register.
3. Also performs authentication and charging
functions.

15.  When either voice or data traffic is originated at the subscriber
terminal, it is transported over the air interface to the BTS, and
from the BTS to the BSC in the same way as a standard GSM
call.
 BSC require a software upgrade, as well as the installation of a
new piece of hardware called a packet control unit (PCU) for
GPRS. The PCU directs the data traffic to the GPRS network and
can be a separate hardware element associated with the BSC.
How voice and data is separated ?

16. How voice and data is separated ? …

17. GPRS Mobility Management
 GPRS Attachment
 GPRS Detachment
 Location Management

18. GPRS Attachment Procedure
 Before a mobile station can use GPRS services, it must register with an
SGSN of the GPRS network. This procedure follows as ;
1. Attach request which includes IMSI which then processed by the
network to P-TMSI.
2. mobile is authenticated with the mobile's Home Location Register
3. SGSN does an update of the GPRS location
4. SGSN sends an "Attach Accept" message to the mobile
5. mobile responds with an "Attach Complete"

19. GPRS Detachment Procedure
 The disconnection from the GPRS. It can be initiated by the
mobile station or by the network (SGSN).
 In MS initiated one; MS informs that it wants to leave the system,
this is MS’s wish. If any contexts are active, network will clear
them. Afterwards MS’s location is not tracked anymore.
 In Network initiated one; Network wants to “get rid of the MS”
because of;
1. Immediate service termination (IST)(E.g. Bills are not paid)
2. Load new parameters (Configuration has been changed and
they should be taken into use)

20. Location Management
 Aim is to keep track of the user's current location, so that
incoming packets can be routed to his or her MS.
 If the MS sends update messages seldom, its location is
not known exactly, resulting in a significant delivery
delay.
 On the other hand, if location updates happen very often, the
MS's location is well known to the network, and the data
packets can be delivered without any additional delay. But,
quite a lot of uplink radio capacity and battery power is
consumed for mobility management.
 A MS can be in one of three states depending on its current
traffic amount; the location update frequency is dependent on
the state of the MS

21.  GPRS attach, the MS gets into READY state. With a GPRS detach it
may disconnect from the network and fall back to IDLE state. All
PDP contexts will be deleted.
 The STANDBY state will be reached when an MS does not
send any packets for a longer period of time, and therefore
the READY timer, which was started at GPRS attach, expires.
 In IDLE state, no location updating is performed, the current
location of the MS is unknown to the network.

22. An MS in READY state informs its SGSN of every movement to
a new cell(in GSM).
In GPRS, for the location management of an MS in STANDBY
state, a GSM location area (LA) is divided into several routing
areas (RA). In general, an RA consists of several cells. The
SGSN will only be informed when an MS moves to a new RA;
cell changes will not be disclosed. Whenever an MS moves to
a new RA, it sends a "routing area update request" to its
assigned SGSN. The message contains the routing area
identity (RAI) of its old RA.
1. In same SGSN routing area update
2. In different SGSN routing area update

23. GPRS Tariffing and Charging
There exists an extra charging gateway and billing system.
Charging gateway makes a log entry whenever there is network
activity such as data being transferred. The main functions of the
charging gateway are the collection of GPRS data records from
the GPRS nodes
GPRS may have many tariffing dimensions;
1. Number of packets transmitted Type of content
2. Value of content Number of messages
3. Number of mails sent and received
4. Mailbox size
5. Number of web pages hit Time of day
6. Location specific Uplink/downlink volume

24. GPRS Performance Categories
They are split into three basic categories according to their capabilities
in terms of the ability to connect
to GSM and GPRS facilities:
 Class A: - This class describes mobile phones that can be
connected to both GPRS and GSM services at the same time.
 Class B: - These mobiles can be attached to both GPRS and GSM
services but they can be used on only one service at a time. A
Class B mobile can make or receive a voice call, or send and or
receive a SMS message during a GPRS connection. During voice
calls or texting the GPRS service is suspended but it is re-
established when the voice call or SMS session is complete.
 Class C: - This classification covers phones that can be attached
to either GPRS or GSM services but user needs to switch
manually between the two different types.

25. Applications of GPRS
1. Textual and Visual Information
2. Still Images
3. Web Browsing
4. Document Sharing
5. Corporate Email
6. Internet Email
7. Vehicle Positioning
8. File Transfer

26. Advantages of GPRS
 Improves the utilization of the radio resources
1. Multiple users can share one physical channel
 Volume-based billing
 Higher transfer rates
1. Max 17 171.2Kbits/sec
 Shorter access times
 Simplifies the access to packet data networks

27. Conclusion
 GPRS Provides Efficient Access To Packet Data Networks
 Multi slot Operation In GPRS Leads To Efficient Channel
Utilization
 GPRS Is More Effective For Long Data Packet Transmission
Than Short Ones.

28. References
 www.google.com
www.wikipedia.com

29. Thank you