Objectives

When you complete the reading in this chapter, you will be able to

• Describe the main components of a GSM network.

• Describe the mobile services.

• Understand how a mobile performs an attach or detach procedure in GSM.

• Discuss the modulation techniques used for GSM.

• Understand the access methods used.

• Describe the overall cellular operation of a radio network.

Welcome to an overview of the General Packet Radio Services (GPRS). GPRS is a radio service that was designed to run on Global Systems for Mobile (GSM), a worldwide standard for cellular communications. Data transmissions in the past were slow across the radio interfaces due to many propagation and reception problems. To create a broadband communications interface, GPRS was developed as a stepping-stone approach to other services like the Enhanced Data for a Global Environment (EDGE). Regardless of the names we place on these services, the real issues are how much (cost) and how fast (speed) we need to meet the demands for data transmission now and in the future.

Before delving directly into the GPRS systems and services, it is prudent to have common ground on the use of the radio-based systems. Therefore, a review (or introduction) of GSM is appropriate. After all, if GPRS is an overlay to GSM, we should at least understand how and why GSM works.

History of Cellular Mobile Radio and GSM

The idea of cell-based mobile radio systems appeared at Bell Laboratories in the early...