Exploiting spatial spectrum holes in multiuser MIMO systems

In this paper, a modified spectrum sensing algorithm for Cognitive Radio is proposed for the detection of spatial spectrum holes. We consider two scenarios, namely, the static and the dynamic scenarios. In both scenarios, by exploiting a priori information about primary users (PUs) activity, a better sensing for spatial spectrum holes in MU-MIMO can be achieved. A Maximum A Posteriori (MAP) detector with relaxed constraints is considered where both the block sparsity structure of the signal being sensed and the knowledge of a priori information about the PUs activity are considered. In the dynamic case, the PUs activity is modeled as a two-state Markov chain.