General Packet Radio Service

Introduction

GSM standard included voice and circuit switched data service. In circuit switched data service, the bandwidth is dedicatedly allocated to a user before data transfer. With increasing user base, the demand for new and higher data rate non-voice services grew. A new switching technique had to be designed. For the same GPRS [General Packet Radio Service] standard with packet switched data functionality was introduced in GSM networks. Table 9.1 lists the significant differences between circuit switched data service of GSM and GPRS.

The development of GPRS standard, which is often referred to as 2.5 G, was started by ETSI/SMG in 1994. As the packet switched principle was employed, this network had the capability to easily communicate with packet-based protocols like IP and X.25. Some new network entities were added in the already existing GSM network to allow the GPRS users to remain connected to the network and on the basis of requirement enjoy the data service. This led to a change in charging principle employed in the GPRS system. Several channel coding schemes were also used to increase per user data rate. Although theoretical data rate for GPRS user is high, in practice, it is averaged around 56 kbps. This standard of wireless communication is often referred to as the first step towards third generation.

Both the subscribers and the service provider have benefitted by the introduction of GPRS services. Some of the noteworthy advantages offered to the subscribers are as follows:

• • Subscribers can enjoy services at higher data rate. Theoretically, the maximum achievable speed is 115.2 kbps. However, in practice, the maximum data rate enjoyed by the end-user is 56 kbps.