Relay communication systems have recently been gaining momentum as an alternative to cellular architectures because of the ability to provide cost-efficient high spectral efficiency communications. The goal of this book is to investigate opportunistic relay communication strategies in various network configurations. We derive the outage probability of opportunistic two-hop multiple relay networks with nodes having single or multiple antennas. The challenge in the analysis of the outage probability are in incorporating realistic channel effects such as path loss, shadowing, and fast fading. We...