Hybrid-MIMO receiver with both space-time coding and Spatial Multiplexing detections for Cognitive Radio networks

In Cognitive Radio (CR) network, the secondary users are required to sense the spectrum based on their environment and then they adapt the spectrum as well as the transmission scheme for CR services to the vacant channels. Multiple-Input Multiple-Output (MIMO) technique becomes an interesting option for CR networks because it can increase the spectrum efficiency and maintain the diversity benefits. In fact, there are two schemes of MIMO transmission including Spatial-Multiplexing (SM) and Space-time block coding (STBC) schemes. These schemes provide the different benefits according to the channel quality or user requirements. Therefore, base station or fusion center must have the capability of detecting both SM and STBC from each CR user at the same time. In this paper, the novel Hybrid-MIMO receiver has been proposed by merging the detection methods of both SM and STBC schemes. The simulation results confirm that the proposed system can improve the symbol error rate and still maintain the benefits of diversity.