SIEMENS
A65 Level 2 Service Manual
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Siemenes Shanghai Technical Support Center
1.5 GPRS (GENERAL PACKET RADIO SERVICE)
GPRS is a new non-voice value added services that allows information to be sent and
received across a GSM mobile telephone network. It supplements today’s Circuit Switched
Data (CSD) and Short Message Services (SMS). GPRS involves overlaying a packet based
air interface on the existing circuit switched GSM network. This gives the option to use a
packet-based data service. The information is split into separated but related “packets” before
being transmitted and reassembled at the receiving end. Theoretically, maximum speeds of
up to 171.2 kilobits per second (kbps) are achievable with GPRS using all eight timeslots at
the same time. This is about 3 times as fast as the data transmission speed possible over
today’s fixed telecommunications networks and 10 times as fast as current Circuit Switched
Data services on GSM networks
.
Example: Cell with 1 Frequency channel:
1 physical channel for signaling, 4 physical channels for Circuit switched and 3 physical
channels
for Packet switched.
