Cognitive radio (CR) techniques improve the spectrum utilization by exploiting temporarily-free frequency bands (i.e., in the time domain). The spectrum utilization can be boosted further if CR nodes are equipped with multiple antennas to leverage communications in the spatial dimension. In this article, we consider the problem of maximizing the throughput of a multi-input multi-output (MIMO) cognitive radio network. With spatial multiplexing performed over each frequency band, a multi-antenna CR node controls its antenna radiation pattern and allocates power for each data stream by appropriately adjusting its precoding matrix. Our objective is to design a set of precoding matrices (one for each band) at each CR node so that power and spectrum are optimally allocated for that node (in terms of throughput) and its interference is steered away from other CR and PR transmissions. In other words, the problems of power, spectrum allocation and interference management are jointly investigat...
Diep N. Nguyen, Marwan Krunz