6. Speech and Channel Coding

6.1 Introduction

Here we will consider two forms of coding techniques used within the GSM system. Firstly
the process used to convert human speech into a digital equivalent and secondly the coding
processes for compressing and protecting the data for transmission over the air interface.
This section also covers the interleaving techniques by GSM to further protect the Air
Interface data from the effects of ‘bursty’ noise and radio interface modulation techniques.