Spread Spectrum Techniques

Abstract

In this chapter we will present the basic idea behind spread spectrum systems together with some of the most important issues regarding their design and implementation. We will start with a definition of spread spectrum systems and consider their advantages as well as their disadvantages, after which the different types will be described. The direct sequence spread spectrum principle will be covered into more detail including a short mathematical representation and the derivation of the optimum receiver, since UMTS relies on this technique. A following section will deal with the very important topic of synchronization and we will close with a short coverage of past and present applications together with some historical notes on the origins of spread spectrum techniques. In this chapter we of course do not intend to cover the topic of spread spectrum comprehensively. We just want to lay the theoretical background of spread spectrum for a sufficient understanding of the CDMA technology and its application within UMTS. As in the foregoing chapters we have included several references to enable the reader to cover topics of interest in more detail.