GPRS

General Packet Radio Service (GPRS), also called 2.5G, is a mobile data standard that is part of the 2G cellular communication network Global System for Mobile Communications (GSM). Networks and mobile devices with GPRS started to roll out around the year 2001; it offered, for the first time on GSM networks, seamless data transmission using packet-switched data for an "always-on" connection, eliminating the need to dial up, providing improved Internet access for web, email, Wireless Application Protocol (WAP) services, Short Message Service (SMS), Multimedia Messaging Service (MMS) and others.

Up until the rollout of GPRS, only circuit-switched data was used in cellular networks, meaning that one or more radio channels were occupied for the entire duration of a data connection. On the other hand, on GPRS networks, data is broken into small packets and transmitted through available channels. This increased efficiency also gives it theoretical data rates of 56–114 kbit/s, significantly faster than the preceding Circuit Switched Data (CSD) technology. GPRS was succeeded by EDGE ("2.75G") which provided improved performance and speeds on the 2G GSM system.

The GPRS core network allows 2G, 3G and W-CDMA mobile networks to transmit IP packets to external networks such as the Internet. The GPRS system is an integrated part of the GSM network switching subsystem.

GPRS is a best-effort service, implying variable throughput and latency that depend on the number of other users sharing the service concurrently, as opposed to circuit switching, where a certain quality of service (QoS) is guaranteed during the connection. It uses unused time-division multiple access (TDMA) channels in the GSM system for efficiency. Unlike older circuit-switched data, GPRS was sold according to the total volume of data transferred instead of time spent online, which is now standard.

GPRS extends the GSM Circuit Switched Data capabilities and makes the following services possible:

If SMS over GPRS is used, an SMS transmission speed of about 30 SMS messages per minute may be achieved. This is much faster than using SMS over GSM, whose transmission speed is about 6 to 10 messages per minute.

As the GPRS standard is an extension of GSM capabilities, the service operates on the 2G and 3G GSM frequencies. GPRS devices can typically use (one or more) of the frequencies within one of the frequency bands the radio supports (850, 900, 1800, 1900 MHz). Depending on the device, location, and intended use, regulations may be imposed either restricting or explicitly specifying authorised frequency bands.

GSM-850 and GSM-1900 are used in the United States, Canada, and many other countries in the Americas. GSM-900 and GSM-1800 are used in Europe, the Middle East, Africa and most of Asia. In South Americas these bands are used in Costa Rica (GSM-1800), Brazil (GSM-850, 900 and 1800), Guatemala (GSM-850, GSM-900 and 1900), El Salvador (GSM-850, GSM-900 and 1900). There is a more comprehensive record of international cellular service frequency assignments