Throughput Analysis of Cognitive MIMO System

In this paper, we consider a simple cognitive MIMO system, in which the cognitive link communicates using two transmission antennas and one receiving antenna. In order to ensure the primary link's transmission unaffected, the cognitive user has to detect the activity of the primary link, and transmit when it senses an idle slot. The maximum stable throughput of the cognitive link in this scenario is derived for a fixed throughput selected by the primary link. In particular, we consider two different scenarios: 1) the ideal system, which assumes that the detection is always correct; 2) the real system, in which detection error occurs due to channel fading. This analysis sheds some light on the research and application of cognitive MIMO technique.