Data in GPRS Networks

The General Packet Radio Service (GPRS) was the first step from European Telecommunications Standards Institute (ETSI) for improving cellular access for packet data networks, such as the Internet. The reason behind GPRS is to introduce packet switching in the GSM network and to optimize radio access for packet networks. GPRS was designed to reuse as many elements of the existing GSM infrastructure as possible, thus optimizing operators' investment in the existing GSM networks. GPRS also allows for later migration to the Enhanced Data for GSM Evolution (EDGE) and the Universal Mobile Telecommunications Systems (UMTS), thus making GPRS a long-term investment for operators.

The EDGE technology is very similar to the GSM technology. It allows data rates of up to 384 Kbps versus 171 Kbps in GSM by using eight time slots of a carrier frequency. The main difference from GSM is the modulation method. EDGE uses 8PSK modulation (3 bits per symbol) instead of GMSK (1 bit per symbol), resulting in increased user bit rates and the possibility for higher coding rates.

This chapter describes GPRS, which was introduced for GSM and is characterized by the Gb interface between the base station controller (BSC) and the core network (CN). This chapter discusses the system architecture, radio, and CN functionalities. It also explains how a GPRS network can be used to transport IP and applications that are based on IP from a user to an external data network.