This figure shows the field structures of the normal burst used in the GSM system. This example also shows that some of the radio channel capacity is used to transfer voice (traffic) information and some of the radio channel capacity is used to transfer control messages. This diagram shows that a simultaneous two-way voice communication session requires at least one radio channel communicates from the base station to the mobile station (called the forward channel) and one channel communicates from the mobile station to the base station (called the reverse channel). This example shows that each radio communication channel is divided into 8 time slots (0 through 7). Each radio channel in the GSM system has a frequency bandwidth of 200 kHz and a data transmission rate of approximately 270 kbps.
This diagram shows that the GSM system uses a single type of radio channel. There are 31 explanatory diagrams in this book You will also discover how 2nd generation systems are gradually evolving into more. You will discover why mobile telephone service providers have upgraded from 1st generation analog systems to more efficient and feature rich 2nd generation GSM systems. This book explains the basic components, technologies used, and operation of GSM systems.