Cooperative Communications: Hardware, Channel & PHY

3

Transparent Relaying Techniques

3.1 Introductory Note

3.1.1 Chapter Contents

Analyzing the physical layer performance of a wireless system is vital in understanding, optimizing and synthesizing system parameters. As of 2009, there are several hundreds of highly complex contributions on transparent PHY layer analysis and design available. This requires us to concentrate on some canonical techniques that can then be applied to other scenarios. For this reason, we proceed in this chapter with the following topics:

• transparent relaying protocols;
• transparent space–time processing protocols;
• distributed system optimization.

Transparent relaying protocols are realized by relays that transparently relay the received signal, either by simply amplifying it or performing some linear (analog) operations. For more general topologies, such as with several serial relaying stages or multiple parallel relaying branches, we will generally assume that these do not interfere. Distributed space–time processing protocols, on the other hand, facilitate distributed space–time transmission with the aid of one or several transparent relays. Note that for the below topologies we assume a sufficient degree of synchronization between nodes, since asynchronous transparent space–time processing protocols are not dealt with in this chapter. Finally, the system optimization includes issues pertaining to distributed power allocation as well as distributed relay selection.

This chapter is fairly short compared ...