GPRS General Packet Radio Service

Group members: Lee Chun Keat(A108613) Loo Pei Yee(A108958) Sit Mun Hon (A108941)

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Introduction

• Packet switched.

• Wireless communications service.

• Based on GSM communication.

• Known as GSM-IP.

• 2G cellular systems combined with GPRS is often described as “2.5G”.

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• Supports a wide range of bandwidths.

• Efficient use of limited bandwidth.

• Suited for sending and receiving small bursts of data.

• Speed – from 14.4Kbps(using 1 radio timeslot) up to 115Kbps(using amalgamating timeslots).

• Data transfer is typically charged of transferred data. 3

GPRS Network Components

BTS – Base Transceiver Station BSC – Base Station Controller SGSN – Service GPRS Support Node GGSN – Gateway GPRS Support Node DHCP – Dynamic Host Configuration Protocol RADIUS – Remote Dial-in User Service DNS – Domain Name System A view of the basic GPRS network components. The functions shown in boxes beneath the network show the different types of network services that are commonly used in a GPRS network. 4

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How does GPRS achieve high speed?

• GPRS uses the same radio channel as voice calls, a channel that is 200kHz wide. • This radio channel carries a raw digital radio stream of 271 kbit/s which, for voice calls, is divided into 8 separate data streams, each carrying approximately 34 kbit/second.

• After protocol and error correction overhead, 13 kbit/s is left for each voice connection or about 14kbit/s for data. 6

• GPRS can combine up to 8 of these channels, and since each of these can deliver up to 14kbit/s of data throughput, the net result is that users will be able to enjoy rates over 100 kbit/s.

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Advantages

End user

• Cost effectiveness – only charged when data is transmitted and not for the duration of the connection.

• Constant connectivity – GPRS enables instant connections and the ability to remain logged-on at all times (Internet or corporate virtual private networks (VPN)).

• Simultaneous voice and data communication – the user can receive incoming calls or make outgoing calls while in the midst.

• Support for leading internet communication protocol – internet protocol.

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Operators/ICPs (Integrated Communication Providers)

• Offer new and improved data services to residential and business markets to aid retention and loyalty.

• Increase revenues from data services.

• Opportunity to increase subscriber numbers.

• Offer innovative tariff based on new dimension such as the number of kilobytes or megabytes.

• Return on investment – investment in GPRS will be twofold since the new network infrastructure pieces will be used as part of the UMTS network requirements as well as GPRS.

• GPRS provides an upgrade path and test bed for UMTS.

• Control of large content portals.

• Access to the key member of the value chain – the customer. • Cost effectiveness through spectrum efficiency.

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• When GPRS packets are sent to a destination they are sent in all different directions - allowing for the potential for one or some of those packets to be corrupted or even lost altogether during the data transmission over the radio link. This is inherent in wireless packet technologies so data integrity and retransmission strategies are incorporated - which in turn result in potential transit delays. 11

• Although available radio resource can be concurrently shared between several users, An increase in the numbers of users will slow data services down for each user. 12

Application of GPRS

• Chat • Information services as test or graphics.

• Still images • Moving images • Web browsing • Document sharing and remote collaborative working • Audio reports • Job dispatch • Corporate email • LAN applications • Internet email • Vehicle positioning • File transfer 13