ABSTRACT
This chapter discusses the main characteristics of the wireless channels. It presents the different common diversity techniques in addition to an introduction to cooperative diversity. The chapter introduces the concept of relay channel which considers the basis for cooperative communications. It also discusses a general overview on the cooperative communications working principle. The chapter describes the different cooperative protocols concerned with the processing of received source information at the relay nodes. It examines the cooperative diversity based on relay selection. The chapter highlights some of the areas where the cooperative relaying strategies can be applied. Path loss, shadowing, and fading are the main impairments which affect the signal transmitted over wireless channels. The chapter explores these three impairments and their effect on the performance of wireless communication systems. Diversity can be achieved through user cooperation, whereby mobile users share their physical resources in order to create a virtual array. The chapter focuses on pros and cons of cooperation.
