Cooperative communications is a new wireless networking paradigm that allows networking nodes to collaborate through distributed transmission and signal processing to implement spatial and time signal diversity to combat the effects of fading channels. These systems exploit the wireless broadcast advantage, where transmissions from an omnidirectional antenna can be received by networking nodes that lie within its communication range. Specifically, in cooperative relaying systems the source broadcasts a message to a number of cooperative relays, which in turn resend a processed version of the information to the intended destination nodes, emulating antenna array effects. The destination nodes combine the signals received from the collaborating relays, either to increase the capacity of communication links or to increase the reliability of transmissions between the source and the destination. This is accomplished with an approach similar to that used in recently introduced space-time coding techniques for multiple-input multiple-output (MIMO) communication systems.