AP75 Level 2 Service Manual
Copyright © Siemens Pte Ltd.
Siemens Technical Support Centre
All Rights Reserved
COM D CCQ APAC PS
Page
4
of
28
Internal Use Only
2 Remark
All instructions given in this document are valid for AP75.
3 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.
