Siemens Gigaset S45, Руководство по обслуживанию

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GPRS
(General Packet Radio Services)
Overview
.
PRS 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.
G
Figure1. Example of GPRS data transmission
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Chapter
1
Example: Cell with 1 Frequency channel:
1 physical channel for signalling, 4 physical channels for Circuit switched
and 3 physical channels for Packet switched