An upgrade to the Time Division Multiple Access (TDMA) cellular phone system. General Packet Radio Service (GPRS) uses packet switching instead of the existing circuit-switching technologies of TDMA systems to provide more efficient use of available bandwidth.
GPRS provides subscribers with up to eight separate 14.4-Kbps communication channels. In theory, GPRS has a maximum data transmission rate of 171.2 Kbps, but in practice the maximum rate is only about 44 Kbps downstream and 22 Kbps upstream because of the overhead of combining channels and the power limitations on the subscriber end. Implementation of GPRS requires that existing TDMA hardware be upgraded accordingly.
Some limited trials of GPRS began in 1999, with widespread trials set to begin in the summer of 2000. A number of European and Asian countries are piloting GPRS systems and have an edge over the United States in the arena of wireless communication systems running at more than 20 Kbps.
With its higher data rates, GPRS makes possible the kinds of wireless applications and services that have simply not been feasible on the existing Global System for Mobile Communications (GSM) circuit-switched data services, which are limited to 9.6 Kbps, or by using the existing Short Message Service (SMS), which is limited to a maximum of 160 characters of transmitted information. Possible uses for GPRS include services such as wireless mobile Web browsing, discussion groups, chat services, mobile commerce, and home automation through wireless remote control.
It is probable that GPRS upgrades will be easiest for carriers whose networks operate in the 1800-MHz or 1900-MHz frequency bands, because they usually have sufficient unused capacity to implement channel aggregation without having to upgrade their bearer equipment. Upgrading to GPRS is more expensive for carriers operating in the 800-MHz or 900-MHz bands because of the near-full capacity of those bands.
Another cost involved in the GPRS upgrade process is that of replacing the circuit-switched core network connecting existing base stations with an IP-based backbone network for interfacing between the wireless system and the Internet. You create an interface between a GPRS network and an Internet Protocol (IP) network by using a gateway GPRS support node (GGSN). You can also use GGSNs to connect GPRS networks with legacy X.25 packet-switching networks.
GPRS might have a short implementation lifetime if the International Mobile Telecommunications-2000 (IMT-2000) initiative from the International Telecommunication Union (ITU) gathers steam, because IMT-2000 upgrades will support data throughput speeds of up to 2 Mbps - much greater than what GPRS can provide.