Automatic Modulation Classification: Principles, Algorithms and Applications

9Modulation Classification for Civilian Applications

9.1 Introduction

In previous chapters we have taken a theoretical view of modulation classification. The listed classifiers have mostly been developed based on general assumptions. The performance comparison in Chapter 8 gives a general impression of how each classifier performs in different scenarios.

In this chapter we visit some of the civilian communication systems with special AMC requirements that have not been covered previously. First, we investigate systems where higher-order modulations are deployed. Secondly, the application of modulation classifiers in link adaptation is revised with specific classifiers designed to exploit some of the properties of the system. Lastly, the case of blind modulation classification in MIMO systems is discussed.

9.2 Modulation Classification for High-order Modulations

In real world communication systems there are many instances where high-order modulations are employed for high data rate transmission. These systems mostly rely on wired transmission links to achieve ultrahigh spectrum efficiency. Among them, 64-QAM and 256-QAM are used for digital terrestrial television and its high-definition version. Broadband over power line (BPL) uses 1024-QAM and 4096-QAM modulations. To design a classifier for high-order modulation over wired channel, we need to understand the following characteristics of these systems.

First, the wired channel is relatively stable compared with wireless channels. ...