General Packet Radio Service (GPRS) is a packet-data technology that allows GSM operators to launch wireless data services, such as e-mail and Internet access. As a result, GPRS provides operators with the ability to use data to drive additional revenue. GPRS is often called a 2.5G technology because it is a GSM operator's first step toward third generation (3G) and a first step in wireless data services.
Although GPRS is a data-only technology, it helps improve GSM voice capacity. When an operator deploys GPRS, it also can upgrade to a vocoder, a new type of voice coder that turns voice into digital signals before they pass across the wireless network. The vocoder uses Adaptive Multi-rate speech transcoding (AMR) technology, which can handle twice as many simultaneous voice calls as a network that uses the old vocoder. As a result, GPRS allows GSM operators to accommodate additional voice traffic without the expense of acquiring additional spectrum.
GPRS supports peak download data rates of up to 115 kbps, with average speeds of 40 to 50 kbps, which is comparable to other 2.5G technologies, such as CDMA2000 1x. GPRS speeds are fast enough for applications such as Multimedia Messaging Service (MMS) and a web browsing experience comparable to a wired dial-up modem. GPRS also allows customers to maintain a data session while answering a phone call, which is a unique and exclusive feature to GSM. GPRS also provides an always-on data connection, so users do not have to log on each time they want data access. The packet architecture also means that users pay only for the data itself rather than for the airtime used to establish a connection and download data.
GPRS is the most widely supported packet-data wireless technology in the world. Like GSM, GPRS supports international roaming so customers can access data services whether they are at home or abroad. When users travel to areas that have not yet been upgraded to GPRS, they still can access many data services via circuit-switched GSM.
The significant global operator and user adoption of GPRS has created a customer base that has attracted dozens of device manufacturers. As a result, thousands of models of GPRS phones and PC card modems are currently available. In fact, virtually all GSM model devices have GPRS.
GPRS builds on the GSM network platform, so operators can leverage their existing infrastructure, such as base stations and Mobile Switching Centers (MSCs). The GPRS core network is based on Internet Protocol (IP) standards, which make it ideal for providing wireless access to other IP-based networks, such as Internet Service Providers (ISPs) and corporate Local Area Networks (LANs). The GPRS core also serves as the foundation for all subsequent steps toward 3G. For example, when operators deploy EDGE and UMTS-HSPA, they reuse GPRS core elements such as Gateway GPRS Support Nodes (GGSNs); this design ensures that each step in the migration to 3G is smooth and cost-effective.