TAS Strategies for Incremental Cognitive MIMO Relaying: New Results and Accurate Comparison

In this paper, we thoroughly elaborate on the impact different transmit-antenna selection (TAS) strategies induce in terms of the outage performance of incremental cognitive multiple-input multiple-output (MIMO) relaying systems employing receive maximum-ratio combining (MRC). Our setup consists of three multi-antenna secondary nodes: a transmitter, a receiver and a decode-and-forward (DF) relay node acting in a half-duplex incremental relaying mode whereas the primary transmitter and receiver are equipped with a single antenna. Only a statistical channel-state information (CSI) is acquired by the secondary system transmitting nodes to adapt their transmit power. In this context, our contribution is fourfold. First, we focus on two TAS strategies that are driven by maxim