Briefing on the technical specification for
General Packet Radio Services (GPRS) and
Wideband Code Division Multiple Access
GPRS - The Basic Principle
General Packet Radio Service (GPRS) provides a means for a data connection to be maintained without
continuous transmission of signals except when data is being passed to or from the terminal. This is a
similar concept for data to discontinuous voice feature is for speech - but with fewer signals needed to
maintain the call during no-data periods.
A GPRS-enabled terminal operates in a similar fashion to a standard GSM terminal with a few basic
differences. Where a network base station carrier frequency is subdivided into eight Tx/Rx time slots and
these can be allocated to eight GSM terminals, a GPRS terminal has the ability to use multiple consecutive
time slots to achieve a greater data transmission or reception rate.
The theoretical limit on this would be to utilise eight time slots, however, this is not desirable from either
the terminal user’s perspective or the network operator’s. The mobile terminal would demand a high
power drain from the battery that could result in short battery life. A network operator may find it
difficult to offer a GPRS eight time slot service as this would require considerable excess capacity to be
distributed across the network to account for user demand.
Most current applications of GPRS are based around higher volumes of data being received by the
terminal than being sent by the terminal, e.g. web browsing and WAP type services. Thus the initial
terminal offerings on the market are based on one or two time slot transmit with a two to four time slot
receive allocation. However, some PC cards may have up to four time slot uplink capability subject to
support from the network.
Relevant GPRS Technical Standard
3GPP TS 05.02 V6.9.2 (2001-4)
GSM/GPRS equipment or mobile phone handsets (MS) are limited to the following maximum power
Nominal Max Power