GPRS, or General Packet Radio Service, is a best-effort packet-switching communications protocol for cellular networks.
GPRS was one of the first widely used data transfer protocols on cellular networks, first standardized in 3GPP's Release 97 in the first quarter of 1998. Commercial cellular networks began to support GPRS in 2000.
GPRS was originally a standard under ETSI but was eventually transferred to the 3rd Generation Partnership Project (3GPP) and published in 1998. As a standard, it is compatible with 2G, 3G and WCDMA networks via the GPRS Core Network.
GPRS is a packet-switching communications protocol, as opposed to other circuit-based switching protocols coming before it on 2G networks. Notably, this means that data delivery is best-effort; latency and deliverability will vary at times. Quality of Service (QoS) is not easily manageable with GPRS because it depends on the number of other users sharing the service.
Before GPRS, there were two commonly used protocols for data transfer: Circuit Switched Data (CSD) and High Speed Circuit Switched Data (HSCSD). While an improvement over previous data solutions (such as cellular modems), they worked in much the same manner as phone calls and were billed similarly by time.
GPRS was an improvement in efficiency and a feature boon for customers as well. Instead of the transmission schemes used in CSD, GPRS uses Time Division Multiple Access (TDMA) and Frequency Division Duplex (FDD) over shared channels to transmit data. It enables always-on internet access as well as Multimedia Messages and other advanced phone features. Additionally, the packet-based routing allows service providers to bill by volume instead of time active.
GPRS and other packet-based data protocols originally built on top of 2G networks earned informal names. Notably, GPRS is often called 2.5G and EDGE (a later, competing technology) is sometimes called 2.75G.
Traditionally, GPRS (2.5G) speeds are quoted over 2G networks; over 2G GPRS can theoretically transmit around 120 kilobits per second. Due to real-world conditions, you can usually expect 20 - 50 kbps. Latency will vary but often can approach .5 to 1 seconds.
EDGE (2.75G) speeds come closer to a 1 Mbit/sec rate, with real-world speeds closer to 150 - 400 kbps.
However, we do not recommend starting new development in the United States with GPRS or on 2G networks. 2G networks are being sunset, and we can't ensure long-term coverage or reliability on 2G networks. We suggest development on 4G.
While we don't currently suggest starting development on a GPRS-based hardware product, Twilio's Programmable Wireless has you covered for your connected device project. We can help take your contribution to the Internet of Things from Dream to MVP (and beyond). Get in touch, and we'll help you evaluate all the options - we can't wait to see what you build.