Telefónica Móviles España

GPRS(General Packet Radio Service)

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GPRS Characteristics• GPRS is a new technology that optimises the use of

network and radio resources:

– Users share radio resources.

– Only used when data are sent or received.

– Uses a packet-mode technique to transfer data and signalling in an efficient manner.

• GPRS data transfer is based on the Internet Protocol (IP). The packet data transmission is carried out on an end-to-end basis, including the air interface.

• GPRS operates on the same radio frequencies as the circuit-switched GSM system. Co-existence of GSM and GPRS networks.

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• Billing based on data volume, NOT on time.

• Data transfer rate depends on the load: number

of users (GPRS and non GPRS).

• GSM-GPRS network turns into a “Wireless LAN” with IP mobile devieces connected.

• Always-ON.

• Assignment divided into uplinks and downlinks.

Introducción

GPRS Characteristics

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What is?

Data transmission technology in mobility

A complement for GSM

Technological support for new services

New business model generator

2.5 G: a step forward 3G

What is NOT?

A substitute for WAP

A substitute for GSM

An alternative to UMTS

A new service

Multimedia services

ADSL for mobile phones

What IS and IS NOT GPRS?

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GSM Voice:GSM Voice: 1 conversation 1 channel1 channel for GSM data 9.6 kbps

1 2 3 45 6 7 8Radio Carrier:Radio Carrier: 8 channels

GPRS:GPRS: Use of until 8 channels per userDepending on the code algorithm, we can get several transmission rates: CS-1: 9.05 kbps/slot CS-3: 15.6 kbps/slotCS-2: 13.4 kbps/slot CS-4: 21.4 kbps/slot

Actually terminals support until 4+1 slots

Efficiency in resources use: until 8 users/channel.

GPRS rates

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GPRS Applications

• Burst Applications with high bandwidth:– E-mail, WWW, FTP

• Applications with low bandwidth: – Telemetry, Remote control, e-commerce.

• Multicast Services:– Metereological, Traffic or Corporate

Information.

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GPRS Architecture

BTS

BSC

MSC/VLR

SGSN

Backbone Network

GGSN

External X.25 Network

ExternalIP Network

AUCHLR

EIR

Traffic and signalling

Signalling

MSMS

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• GPRS is implemented on the GSM structure through the addition of two new network nodes:– SGSN (Serving GPRS Support Node) provides packet

routing to and from the geographical SGSN area.

– GGSN (Gateway GPRS Support Node) provides interworking with external packet-switched networks.

• BSC needs a SW and HW upgrade, the PCU (Packet Control Unit).

GPRS Architecture

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SGSN Main Tasks

• Packet routing towards the adequate GGSN.• Security over radio access: ciphering and

authentication.• Mobility management: keeps track of the MS

(Mobile Station) location.• Logical link management towards the MS.• Connection to GSM nodes: MSC, HLR, BSC,

SMS-C.• Charging data.

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• Interface with the external IP packet networks.

• Security functions toward the Internet (Radius client).

• GPRS session management on IP level; communication setup towards external network.

• Associating subscribers with the appropriate SGSN.

• Charging data.

GGSN Main Tasks

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PCU Main Tasks

• Multiplexing of GPRS traffic and circuit switched traffic.

• Handling of GPRS radio resources: allocating channels for GPRS connections.

• Distribution of packet data to the MS.

• Handling connections towards the SGSN.

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BTS & HLR

• BTS (Base Transceiver Station): Responsible for separating the MS originating circuit-switched (CS) calls from packet data communication before the BSC forwards:– CS calls to the MSC/VLR– PS data to the SGSN

• HLR (Home Location Register): The subscriber file must contain GPRS subscription data:– Address of the SGSN currently serving the subscriber– Addresses of GGSNs that will be contacted when activity

from MS is detected– Access Point Name (APN) describing the access point

to the external computer network

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GPRS security

• SGSN performs authentication and cipher setting procedures based on the same algorithms, keys, and criteria as in existing GSM.

• SGSN and GGSN use GTP (GPRS Tunnelling Protocol) in order to encapsule the packets. GTP is assembled over TCP/IP.

• Tunnelling: The information will be ciphered and additional data will be included to every packet to guarantee confidentiality.

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GPRS MoviStar Services

• e-moción GPRS: Mobile Internet Access Service. It uses WAP protocol over GPRS to access to different contents in e-moción.

• MoviStar Internet: Allows to surf to everywhere and everytime with only a laptop or PDA and a MoviStar GPRS mobile telephone. The customer has direct, generic and anonymous access to Internet without the need of an ISP.

• MoviStar Intranet: Allows direct access to LAN networks and corporate applications (Intranet, e-mail, databases, corporate directory, agenda) everywhere and everytime with only a laptop or PDA and a MoviStar GPRS mobile telephone.