Cooperative Communications: Hardware, Channel & PHY

2

Wireless Relay Channel

2.1 Introductory Note

2.1.1 Chapter Contents

Channel models are of utmost importance in the designing process of wireless systems, because they influence power budget dimensioning, transceiver design, performance behavior, etc. Some of their impact will become evident in Chapters 3 and 4. As of 2009, however, there are only a few relaying and cooperative channel measurements and models available as compared to traditional cellular systems. Issues pertaining to channel modeling for cooperative systems will hence be dealt with in this chapter in the following order:

• general channel characterization;
• channel for regenerative relaying (decoupled channel);
• channel for transparent relaying (cascaded channel);
• distributed MIMO channel.

The properties of the regenerative relaying channel can be used to understand and quantify the performance of regenerative relaying protocols, such as the DF and CF protocols to be discussed in Chapter 4. Likewise, the properties of the transparent relaying channel can be used to understand the performance of transparent relaying protocols, such as the AF protocol to be discussed in Chapter 3. The aim of this chapter however is not to go into great channel modeling details but rather to indicate tendencies and issues that are important in modeling the cooperative relaying channel and which impact the performance of cooperative algorithms.

2.1.2 Choice of Notation

Concerning the notation, we will often but not always adopt the ...