Sony Ericsson J200 Benutzerhandbuch

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White Paper 
J200
16
November 2004
General Packet Radio Services
The introduction of GPRS (General Packet Radio 
Services) is one of the key steps in the evolution of 
today’s GSM networks for enhancing the capabili-
ties of data communication. Data traffic is increas-
ing enormously (over both wired and wireless 
networks), with the growth in demand for Internet 
access and services paralleling that for mobile 
communications.
The demand for high-speed Internet access will be 
the key driver for coming generations of wireless 
services, and GPRS can deliver the necessary 
speed. GPRS allows creation of innovative serv-
ices, makes it possible to address new and previ-
ously inaccessible market segments and increases 
customer loyalty.
GPRS applications can be developed as both hori-
zontal and vertical. Vertical applications are spe-
cific, including those for operations such as 
reaching police and emergency, taxi, delivery or 
automated services (vending machines, supervi-
sion, vehicle tracking). Horizontal applications are 
more generic and include those for Internet access, 
e-mail, messaging, e-commerce and entertain-
ment. 
GPRS is able to take advantage of the global cov-
erage of existing GSM networks. Applications 
developed for GPRS can be deployed on a large 
scale and can reap the associated benefits. GPRS 
also provides a secure medium for connections to 
banking and financial services.
Using GPRS in the J200
Instead of occupying an entire voice channel for 
the duration of a data session, the J200 sends/
receives data in small packets, as needed, much 
like IP on the Internet. Because of this, the J200 
maintains a constant online connection, its data 
transmission abilities summoned by the application 
in use on an as-needed basis.
The GPRS specification includes four coding 
schemes – CS1, CS2, CS3 and CS4 – that allow 
data speeds of 9,050 bps, 13,400 bps, 15,600 bps 
and max 21,400 bps per slot, respectively. The 
J200 works with all four coding schemes, but data 
speed naturally varies according to network config-
uration. At the moment, CS-3 and CS-4 are not 
supported in any live network, i.e, present speed is 
limited to 53,600 bps.
The GSM system limits the ability to use all eight 
time slots, so the J200 uses up to four time slots 
for receiving data, and one slot for transmitting. 
This means the speed for receiving data is up to 
85,600 bps and up to 21,400 bps for sending data.
Using GPRS with the J200 has several advantages, 
for example:
Constant connection
High speed
Automatic access to increased bandwidth while 
downloading large files such as pictures and 
sounds
Cost efficiency
Use of transmission capacity only when needed 
to reduce cost
WAP over GPRS
Access to Internet via WAP at high speed and 
with a constant connection.
Provide settings
Receive GPRS configuration settings from the 
provider over the air, OTA, making manual con-
figuration unnecessary.
User controlled settings
Take advantage of full user control in the data 
connections menu, establishing multiple 
descriptions and accessing advanced settings 
for GPRS.
Interruption of GPRS data account
When the user is using WAP via GPRS on the J200, 
the GPRS connection is automatically discon-
nected when the user answers an incoming call. 
However, when the call has ended, the user is 
given the possibility to resume the WAP session.