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Functionality/Operation
GPRS Overview
GPRS Overview
This section summarizes the functional features of the General Packet Radio
Service, or GPRS, for the Test Set installed with Option 040.
Difference from HSCSD
A single user can establish a call on more than one timeslot for the data transfer
using a GSM data service called HSCSD, or High Speed Circuit Switched Data.
GPRS is an overlay for the current GSM system that requires only software and a
couple of new network components to work, and it allows users to transmit and
receive over more than one channel. Both schemes can achieve similar data
transfer rates, but the fundamental differences to move data are as follows:
GPRS:
Uses packet switching that transfers data in little chunks over
several virtual connections.
Applies only a loose relationship between the same number
uplink and downlink timeslot, and allows multiple users to share
a single timeslot.
HSCSD:
Uses circuit switching that transfers data in a single big block
over a dedicated point-to-point connection.
GPRS Network Topology
Focusing on one of the base transmission stations among other GPRS network the
typical functional structure is illustrated as follows:
Abbreviations in the illustration:
Base Station Controller
CSPDN:
Circuit Switched Public Data Network
GGSN:
Gateway GPRS Support Node
MSC:
Mobile-services Switching Center
PLMN:
Public Land Mobile Network
4. Functionality /
Operation
Chapter 4
BSC:
171