This research paper summarizes the principles and use of GPRS (General Packet Radio Service) as a 2.5G mobile data system and transition technology towards 3G networks. It describes how GPRS allows packet data transmission within existing 2G GSM infrastructure at moderate bit rates. It also discusses GPRS limitations and security aspects. Finally, it introduces EDGE as an enhanced version of GPRS that achieves higher speeds and concludes that GPRS/EDGE serves as an important transition technique towards 3G networks like UMTS since existing GSM infrastructure can be reused.

1. Research Paper # 1
ON THE WAY TO 3G NETWORKS:
“THE GPRS/EDGE CONCEPT”
Vasil P. Pribylov , Member ,IEEE, Ivan I.Rezvan
Siberia State University of Telecommunications & Informatics
Email: v.pribylov@ieee.org
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2. Abstract
 Describe Principles and use of GPRS.
 Main problems of transition towards the UMTS
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3. Introduction
 Growing interest in mobile data applications lead a cause of GSM to
GPRS
 GPRS a 2.5 G system allows the transmission of packet data at
moderate bit rates using random access channels within the 2G
infrastructure.
 Mobile applications contain several characteristics that enhance the
value to the customers Like
 mobility(constant voice & data services while on the move)
 immediacy (obtaining connectivity when needed, regardless of
location and without a lengthy login session).
 localization (allows subscribers to obtain information on
their current location) 3

4. Introduction cont….
 GPRS Protocol Stack is important as a migration step
toward third-generation (3G) networks.
 When GSM operators start to offer GPRS services, they
can use their existing networks and gradually assign
part of their resources from circuit-switched voice
services to packet-switched data services.
 This allows a smooth transition from voice-only to
multimedia service networks.
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5. GPRS BACKGROUND
 Enable new & existing applications onto GSM
 Enhancement of GSM’s functional & QoS parameter.
 GPRS shall support both connectionless & connection oriented
services.
 Offer flexible service at low cost to the user.
 Use scarce network resources as efficiently as possible
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6. GPRS BACKGROUND cont……
 Required to efficiently use network resources for packet mode
applications.
 New mechanisms are required in order to provide highly standardized,
feature rich services.
 Three types of service request were distinguished:
1-Broadcast:A point to multipoint message sent to “all service
subscribers” within an area defined by the service requester.
2-Multicast:A point to multipoint message sent to “”an identical
subset of all service subscribers” within the area defined by the
service requester.
3-Singlecast:A point to point message sent to “a unique subscriber”.6

7. GPRS BACKGROUND cont……
 The GPRS operator shall be responsible for
transferring data between the service access points
at the fixed side and at the mobile side. The flow of
data shall be possible in three scenarios.
1. Packets sent from a mobile access point to a
fixed network access point.
2. Packets sent from a fixed network access point
to a mobile access point.
3. Packets sent from a mobile access point to a
mobile access point via the GSM operator
infrastructure
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8. Principles of GPRS
 Users specifically need a mobile phone or terminal supporting GPRS ,
subscription to a network.
 GPRS network resources accessed only when data actually need to be
transmitted between the GPRS user and the network.
 Data are divided into packets and then transmitted via the radio & core
GPRS network.
 Packet switched traffic is separated from circuit switched traffic at
BSC & diverted to GPRS core network.
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9. Principles of GPRS (Cont.)
 GPRS use GMSK modulation scheme.
 Information is coded in the increase(+ve shift) or (-ve shift) of the
carrier phase.
 In GMSK ,initially signal passed through pre-modulation Gaussian
filter for pulse-shaping.
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10. GPRS NODES
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11. Link Layer Performance of GPRS Network
 Frequency reuse factor
 Error coding scheme(CS)
 Data packet delay
Strong channel coding: convolutional code recovers most of the
transmission errors. However , the effective throughput of data packets
is small due to the low code rate.
Weak channel coding: Each RLC block carries a high payload & the
whole RLC block has to be retransmitted.
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12. GPRS Limitations & Security Aspects
 Theoretical maximum GPRS data transmission speed only when a user
utilize eight timeslots without any protection.
 Bandwidth available to a GPRS user is severely limited.
 Misuse of their resources by unauthorized persons using manipulated
mobile stations.
 Eaves-dropping the information being exchanged on the radio path.
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13. GPRS Limitations & Security
 MS authentication: Protection of GPRS subscribers by denying
intruders the ability to impersonate authorized users
 Access Control: Network can support restrictions on access by or to
different subscriber e.g. location, screening lists etc.
 User Identity Confidentiality: User identity is not disclosed to
unauthorized individuals, entities or processes.
 User Information Confidentiality: the property that the user
information is not made available or disclosed to unauthorised
individuals, entities or processes. The purpose is to provide for
confidentiality of user data. 13

14. EXPERIMENT
 experimented with the Eriksson R580m mobile phone
 (using “4+1” time slots four slots in “downlink” for
receiving and one slot in “uplink” for requesting the
information
 GPRS connection with one of Novosibirsk GPRS
operators – Siberia Cellular Systems network of Russia.
 web-site www.nsk.mts.ru
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15. Result
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16. INTRODUCING EDGE
 EDGE is an enhanced version of GPRS
 using a different modulation technique, eight-level
Phase Shift Keying (8PSK), that has a spectral
efficiency of 3bits/s/Hz in comparison of GMSK’s
1bit/s/Hz.
 For this reason EDGE requires a hardware upgrade of
the RF part in the base stations.
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17. Conclusion and Future Work
 GPRS allows network operators to implement an IP-based core
architecture for data applications, which continues to be used and
expanded upon in 3G services for integrated voice and data
applications
 Speed is still not fulfilling the demand of customers.
 Advancement in GPRS system will be the use of improved coding
techniques.
 GPRS proves to be a testing & development area for new services &
application which will be used for 3G services.
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18. Conclusion and Future Work
 ,GPRS/EDGE acts as transition technique towards 3G
& a great need of UMTS/GSM dual-mode.
 But UMTS operators can not start planning from zero
 since the best solution is that the existing GSM base
station sites are to be the primary sites for UMTS base
stations.
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19. REFERENCES
 [1] GPRS Overview,
http://www.vocal.com/data_sheets/gprs1.html.
 [2] GSM World: GPRS Platform,
http://www.gsmworld.com/technology/gprs/index.sht
ml.
 [3] ETSI TR 101.186 V6.0.0 (1998-04): “General Packet
Radio Service (GPRS)”, 19 p.
 [4] Cellular System Solutions for GSM/GPRS Wireless
Terminals, 21 March 2003,
http://www.3g.co.uk/PR/March2003/5070.htm.
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20. Thank you
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