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Introduction To GPRS & 3G

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Packet-switching technology

Transparent end-to-end data transport of data packets over a modified GSM network

Shares Radio Resources with GSM

New GPRS core network different from GSM

GPRS Features

Introduces new air interface coding schemes

Introduces Quality of Service (QoS) profiles

Supports low and high speed (9.6-171.2kbps) data

Supports multiple Packet Data Protocols (PDPs)

Supports SMS over GPRS

Allows for shared usage of GSM control functions

The GPRS Network Elements

USIM is UMTS Subscriber Identity Module (USIM): • subscriber-specific data • support of authorized access to network

Radio Network System (RNS): Provide access to the UMTS terrestrial radio interface

Radio Network Controller (RNC) •Radio mobility management • Management of radio resources

Base Station (Node B) • Radio coverage of cells • Physical layer processing

Mobile-services Switching Centre (MSC) An exchange performing all the switching and signaling functions (CS only) for mobile stations MSC controls mobile-originated and mobile-terminated CS calls


– call management, – mobility management (handling attach and authentication) – subscriber administration– maintenance of charging data (for radio network usage) – CS data services (FAX, modem)– supplementary call services (call forwarding, etc.) – SS7-based signaling

Main difference to an exchange in a fixed network: deal with mobility (e.g. location registration, handover)

Gateway MSC (GMSC) – Provides interconnection between the UMTS core network and external  PSTN/ISDN networks GSNs constitute the interface between the radio access network and the  fixed networks for packet switched services (similar to MSC for CS calls)

Serving GSN (SGSN)

– session management – mobility management – subscriber database management (interface with HLR) – maintenance of charging data (for radio network usage) – IP-based transport of user data between SGSN and the UTRAN– IP- or SS7-based signaling transport

Gateway GSN (GGSN)

– gateway for UMTS packet service to external data networks (e.g. the Internet) – IP interface towards SGSN – performs user data screening and security – maintenance of charging data (for external data network usage)

Home Location Register (HLR) and Visitor Location Register (VLR)

Authentication Centre (AuC) The AuC transmits the data needed for authentication and ciphering via the HLR to the VLR, MSC and SGSN which need to authenticate a mobile station

Equipment Identity Register (EIR) Logical entity storing the International Mobile Equipment Identities (Equipment is classified as

– white listed: serie number of equipment  – grey listed: equipment tracked by network – black listed: barred equipment – unknown to EIR)

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Base Station Subsytem (BSS) Modifications

BTS Requires software upgrade

Inclusion of a CCU in the BTS

BSC requires software upgrade and addition of PCUSN

PCUSN can contain multiple PCUs


Packet Control Unit Support Node (PCUSN)

CCU Functions:

– Data coding / decoding (CS1-4)

– CS 1-2 require software upgrade only

– CS 3-4 require hardware upgrade

– Forward error correction (convolution coding)

– Air interface interleaving

– Radio channel measurements (RxQual)

– Radio management


GPRS Core Network Elements

The following GSM network changes are required:

New GPRS entities:

– serving GPRS Support Node ( SGSN)

– Gateway GPRS Support Node (GGSN)

Modified GSM entities:




 ادامه مطلب و دانلود مقاله 


General Packet Radio Service (GPRS) For Engineers, Aircom International.

– Justin Champion, Mobile Computing Systems: UMTS, Staffordshire University, UK.

– Tony Sung, 3rd Generation WCDMA / UMTS Wireless Network, MC Lab, IE CUHK, 2003.

– Kari Aho,Wideband Code Division Multiple Access (WCDMA) for UMTS, Magister